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The objective of this paper is to investigate the effects of spatial variability in coastal silty soil properties on the stability and failure probability of deep excavation. A super-large irregularly shaped deep excavation in the coastal area in Wenzhou, China, is considered. A numerical model is established based on the random field theory, finite difference method and Monte-Carlo simulation method. Focusing on the friction angle and cohesion, the effects of horizontal and vertical correlation distances and variation coefficients on excavation stability are systematically studied. Meanwhile, the reliability evaluation approach is also applied to systematically examine the impact of the correlation distance on the surface settlement and horizontal displacement of pile. The results show that the greater correlation distance leads to a larger dispersion degree of the ground settlement curve and the displacement curve of the diaphragm wall around. The influence of the horizontal correlation distance on land settlement is more significant. The horizontal and vertical displacements of the pile top are less affected by the correlation distance. Compared with the deterministic analysis, the random analysis results considering the soil spatial variability produce larger displacement.

The application of ductile rock bolts has been a crucial method for solving the problems of large deformations, energy absorption and stability control issues in deep rock masses. To study the anchoring mechanism of the key expansive structure, this paper proposes a novel type of bolt — the Ductile-Expansion bolt, and conducts research on anchoring mechanics, energy absorption characteristics, and failure modes of the bolt. In addition, this paper defines the concept of load-volume ratio of metal rock bolts and proves the Ductile-Expansion bolt is capable of better improving the unit volume bearing capacity of the bolt material. Furthermore, laboratory and field tests verify the Ductile-Expansion bolt had better anchoring effect than the traditional rebar bolt, with the expansion structure favorably enhancing the ductility and energy absorption performance of the bolt. Finally, this paper microscopically analyzes the crack propagation and distribution morphology of the bolts by establishing a 3D coupled numerical model based on FDM-DEM. Numerical results illustrate the interface at the variable diameter of the Ductile-Expansion bolt serves as the transition zone between high and low stress levels. The expansion structure can impose radial compression on the medium around the bolt, which can improve the bolt anchorage performance.

Abstract The influencing mechanism of impact loads on the pore morphology of high‐rank coal has been extensively investigated since mining safety is greatly determined by the ensuing state of gas occurrence. In this work, we propose a combined use of a scanning electron microscope and Image Pro Plus software to examine the impact‐induced changes in pore characteristics. Impact loads of 0, 28.46, 51.8, and 58.7 MPa were applied to the coal samples in various directions (parallel/vertical/45° oblique). The results show that the pore connectivity of coal samples is enhanced following the impact load, and the number and diameter of pores are significantly increased on the whole. Surface porosity and roundness of the coal body first rise and then fall as the impact load increases. Following the impact load, surface porosity and roundness of the coal body significantly increase in the vertical and oblique bedding directions, while decreasing in the horizontal bedding direction.

Abstract Background Papillary thyroid carcinoma (PTC) is globally prevalent and associated with an increased risk of lymph node metastasis (LNM). The role of cancer-associated fibroblasts (CAFs) in PTC remains unclear. Methods We collected postoperative pathological hematoxylin–eosin (HE) slides from 984 included patients with PTC to analyze the density of CAF infiltration at the invasive front of the tumor using QuPath software. The relationship between CAF density and LNM was assessed. Single-cell RNA sequencing (scRNA-seq) data from GSE193581 and GSE184362 datasets were integrated to analyze CAF infiltration in PTC. A comprehensive suite of in vitro experiments, encompassing EdU labeling, wound scratch assays, Transwell assays, and flow cytometry, were conducted to elucidate the regulatory role of CD36+CAF in two PTC cell lines, TPC1 and K1. Results A significant correlation was observed between high fibrosis density at the invasive front of the tumor and LNM. Analysis of scRNA-seq data revealed metastasis-associated myoCAFs with robust intercellular interactions. A diagnostic model based on metastasis-associated myoCAF genes was established and refined through deep learning methods. CD36 positive expression in CAFs can significantly promote the proliferation, migration, and invasion abilities of PTC cells, while inhibiting the apoptosis of PTC cells. Conclusion This study addresses the significant issue of LNM risk in PTC. Analysis of postoperative HE pathological slides from a substantial patient cohort reveals a notable association between high fibrosis density at the invasive front of the tumor and LNM. Integration of scRNA-seq data comprehensively analyzes CAF infiltration in PTC, identifying metastasis-associated myoCAFs with strong intercellular interactions. In vitro experimental results indicate that CD36 positive expression in CAFs plays a promoting role in the progression of PTC. Overall, these findings provide crucial insights into the function of CAF subset in PTC metastasis.

Hydrogen peroxide (H2O2) sensing has been widely investigated using various electrochemical methods, yet the challenge of finding an imaging technique capable of real-time, spatially resolved detection remains. Addressing this, we introduce a Prussian blue (PB) nanofilm-sensitized plasmonic electrochemical microscopy (PEM) technique that successfully visualizes the localized delivery of H2O2. The PB nanofilm was carefully characterized, and its sensing capability towards H2O2 was demonstrated in amperometric mode. Employing a precise micromanipulator system, we controlled a micropipette to create a localized concentration gradient on the sensor surface and monitored the gradient through the PB nanofilm-sensitized PEM. The accuracy of the obtained concentration values was further validated by numerical simulations based on finite-element methods. Our technique ensures dependable localized detection, and we anticipate that advancements in film uniformity will further improve the resolution. The potential applications of this technique are broad and significant, including the opportunity to investigate single-cell exocytosis with neurotransmitters like dopamine, thus offering a promising avenue for future biomedical research.

Abstract Wearable sensors hold immense potential for real‐time and non‐destructive sensing of volatile organic compounds (VOCs), requiring both efficient sensing performance and robust mechanical properties. However, conventional colorimetric sensor arrays, acting as artificial olfactory systems for highly selective VOC profiling, often fail to meet these requirements simultaneously. Here, a high‐performance wearable sensor array for VOC visual detection is proposed by extrusion printing of hybrid inks containing surface‐functionalized sensing materials. Surface‐modified hydrophobic polydimethylsiloxane (PDMS) improves the humidity resistance and VOC sensitivity of PDMS‐coated dye/metal‐organic frameworks (MOFs) composites. It also enhances their dispersion within liquid PDMS matrix, thereby promoting the hybrid liquid as high‐quality extrusion‐printing inks. The inks enable direct and precise printing on diverse substrates, forming a uniform and high particle‐loading (70 wt%) film. The printed film on a flexible PDMS substrate demonstrates satisfactory flexibility and stretchability while retaining excellent sensing performance from dye/MOFs@PDMS particles. Further, the printed sensor array exhibits enhanced sensitivity to sub‐ppm VOC levels, remarkable resistance to high relative humidity (RH) of 90%, and the differentiation ability for eight distinct VOCs. Finally, the wearable sensor proves practical by in situ monitoring of wheat scab‐related VOC biomarkers. This study presents a versatile strategy for designing effective wearable gas sensors with widespread applications.

BackgroundAn association between atmospheric fine particulate matter (PM2.5) exposure and Parkinson's disease (PD) has been suggested by previous studies, but the results of current epidemiological studies are still inconclusive. ObjectiveTo systematically evaluate the relationship between exposure to ambient PM2.5 and the risk of PD, as well as to explore potential influencing factors, aiming to provide scientific evidence for formulating early prevention strategies for PD. MethodsCochrane Library, PubMed, Web of Science, Medline, Embase, China National Know-ledge Infrastructure (CNKI), Wanfang Database, and VIP Chinese Science and Technology Journal Database were queried. The search terms included Parkinson's disease, particulate matter 2.5, and PM2.5 in both Chinese and English. Cohort studies examining the association between atmospheric PM2.5 exposure and the risk of PD were collected and searched from the inception of each database to June 26, 2023. The identified literature was screened, and the basic information of the included studies and their research subjects, outcome indicators, quantitative results of each study, as well as the information required by bias risk assessment were extracted. The Newcastle-Ottawa Scale was employed to assess the risk of literature bias. Meta-analysis, subgroup analysis, sensitivity analysis, and publication bias analysis were conducted in Stata 15.0 software. ResultsTwelve cohort studies were identified. A total of 17443136 participants with follow-up periods ranging from 3.5 to 22 years were included in the analysis. The meta-analysis, utilizing a random-effects model, revealed that PD risk was elevated by 6% after exposure to PM2.5 [HR=1.06 (95%CI: 1.02, 1.11), P=0.006]. The subgroup analysis demonstrated that exposure to PM2.5 increased PD risk by 6% in North America [HR=1.06 (95%CI: 1.00, 1.12), P=0.033] and by 17% in East Asia [HR=1.17 (95%CI: 1.02, 1.33), P=0.020]. However, the effect was not statistically significant in Europe. PD risk exhibited a 7% rise [HR=1.07 (95%CI: 1.02, 1.14), P=0.011] in individuals aged 60 years and older, which was different from that in individuals younger than 60 years. Exposure to various concentrations of PM2.5 was observed to associate with an elevated risk of PD. The inclusion of adjustments for PD-related comorbidities did not alter the conclusion that ambient PM2.5 exposure might elevate the risk of PD. The studies with a follow-up duration exceeding 5 years and reporting more than 1000 PD cases suggested a significant increase in the risk of PD due to ambient PM2.5 exposure [HR=1.06 (95%CI: 1.01, 1.12), P=0.012; HR=1.06 (95%CI: 1.01, 1.11), P=0.027, respectively]. Conversely, no significant association was identified between ambient PM2.5 exposure and the risk of PD within the cohorts with a follow-up duration of less than 5 years and reporting fewer than 1000 PD cases [HR=1.09 (95%CI: 0.95, 1.26), P=0.214; HR=1.12 (95%CI: 0.98, 1.02), P=0.092, respectively]. The sensitivity analysis showed that the results were stable. The publication bias analysis and the combined trim-and-fill method showed that the results were robust. ConclusionThe risk of PD could be increased by ambient PM2.5 exposure and influenced by age and area. The research results might be affected by the duration of follow-up and the quantity of PD cases reported.

Decrease in the cost of acquiring 3D point cloud data coupled with the rapid advancements in GPU computing power have resulted in an increased demand for 3D point cloud semantic segmentation in numerous 3D visual applications, including but not limited to autonomous driving, industrial control, and MR/XR, which further advances the development of deep learning methods in 3D point cloud semantic segmentation. Recently, many novel deep learning network architectures, such as RandLA-Net and Point Transformer, have been proposed and have achieved notable improvements in semantic segmentation accuracy while decreasing the computational load. However, previous research on 3D point cloud semantic segmentation methods has focused primarily on relatively early works, whose approaches have been gradually abandoned over the years and cannot accurately reflect the current research status. Moreover, the existing methods have been categorized based on their input data types, making it difficult to compare the segmentation performance of different techniques and not providing a comprehensive view of the relationship between methods using different network architectures. Therefore, this paper reviews the mainstream 3D semantic segmentation methods developed in the last three years using different deep learning network architectures and is organized into three levels. First, the two principal 3D point cloud data acquisition methods, including their customary datasets and metrics to evaluate model performance, are introduced. Second, a systematic review of 3D semantic segmentation methods based on different network architectures is organized, followed by a statistical analysis of the evaluation of performance between different models on two 3D segmentation datasets—S3DIS and ScanNet. The analysis of model performance on these two commonly used datasets includes model structure relevance, strengths, and limitations. Finally, an insightful discussion of the remaining methodological and application challenges and potential research directions is provided. This paper offers an extensive overview of the recent three-year research progress in 3D point cloud semantic segmentation and summarizes various network architecture pipelines, elucidates their fundamental operations, compares the model performance across multiple architectures, discusses their notable strengths and limitations, most importantly, concludes the current challenges and promising research directions for future investigations. Furthermore, this paper enables researchers to effortlessly identify the relevant research and research hotspots among different 3D point cloud semantic segmentation methods based on the analyses presented and aims to update the reviews on 3D point cloud semantic segmentation methods with a better viewpoint and highlight key properties and contributions of proposed methods, providing promising research directions for the main challenges.

Holes and joints are widespread and coexisting flaws in natural rock. The spatial distribution of combined flaw significantly affects the instability process of fractured rock. To study the influence of ligament length and joint angle on failure characteristics, uniaxial compression experiments are carried out on specimens containing hole-joint combined flaw assisted by acoustic emission (AE) and digital image correlation (DIC) technologies. As the ligament length increases, the mechanical parameter curves decrease first and then rise, showing a U-shape or V-shape. DIC results show that the hole performs a strong inhibition on the crack propagation from the inner joint tips, which will be weakened with the increase of ligament length. The driving displacement field of wing cracks and the type of cracks outside the joint are affected by joint angle variation. The cracks in rock bridge area are generally tensile-shear or shear type. According to AE analysis, the proportion of tensile signals decreased from the pre-peak failure stage to the post-peak stage, and the tensile signal is lower than 50% in the late loading stage, indicating that the shear crack dominates the final failure of specimens.

BackgroundThe World Health Organization has proposed a worldwide target of eliminating hepatitis C virus (HCV) by 2030. A better understanding of HCV, testing behaviors, and associated factors in the general population is essential. ObjectiveThis study aimed to assess HCV knowledge, self-reported HCV testing behavior, and willingness to undergo HCV screening in the general Chinese population. MethodsA cross-sectional online survey of the general Chinese population aged ≥15 years was conducted from November 2021 to May 2023. Participant characteristics were assessed based on their knowledge level and uptake of HCV testing. Participants ever having heard of HCV were recognized as being aware of HCV and asked additional HCV knowledge questions using a brief, validated 9-item scale. Participants with 0-3 points and who were unaware of HCV were categorized as having poor knowledge, and those with 4-6 points and 7 points were categorized as having fair and good knowledge, respectively. Participant uptake of HCV testing, testing results, reasons for undergoing or not undergoing HCV testing, and willingness to undergo HCV screening were collected through self-reports. Ordinal and binary logistic regression analyses were used to assess factors associated with the HCV knowledge level and the uptake of HCV testing, respectively. ResultsA total of 1491 valid participants’ questionnaires were included. Of these, 714 (47.6%) participants were aware of HCV. The proportion of participants with poor, fair, and good HCV knowledge was 63.4% (945/1491), 9.3% (139/1491), and 27.3% (407/1491), respectively. A total of 465 (31.2%) participants reported ever undergoing HCV testing, and 4 (0.9%) were anti-HCV antibody positive. Most participants were tested for HCV following blood donation (353/465, 75.9%). The most common reasons for not undergoing HCV screening were a lack of HCV awareness (665/1026, 64.8%), followed by a low self-perceived risk of infection (176/1026, 17.2%). Of 1026 participants who had never undergone HCV testing, 937 (91.3%) were willing to undergo HCV screening if universal screening was provided at no cost. The HCV knowledge level was positively associated with the HCV testing rate. Participants who were less educated, lived in rural areas, resided in West China, and were currently alcohol drinkers had lower HCV knowledge and reduced odds of having undergone HCV testing. In contrast, participants with a blood donation history and a family history of hepatitis B virus or HCV infection had higher HCV knowledge and increased odds of prior testing. Participants aged ≥60 years had lower knowledge, and women had reduced odds of having undergone previous HCV testing. ConclusionsThe general population of China has low HCV knowledge and testing rate. There is an urgent need for enhanced HCV awareness and scaled-up HCV screening and treatment. Individuals who are less well educated, reside in less-developed areas, currently drink alcohol, and are female should be prioritized for health education and interventions.

BackgroundIn order to improve the safety of lumbar puncture (LP), we designed a new type of LP needle, that is, an integrated and controlled LP needle, which can actively and accurately control the flow rate and retention of cerebrospinal fluid (CSF) during puncture, so as to achieve a controlled LP procedure.ObjectiveTo evaluate whether a controlled LP procedure can improve the comfort of LP and reduce the risk of complications associated with LP.MethodsPatients requiring LP (n = 63) were pierced with an integrated and controlled LP needle or a conventional LP needle. The differences in vital signs, symptom score, comfort, operation time, CSF loss, CSF pressure fluctuation and back pain before and after puncture were analyzed.ResultsAn integrated and controlled LP needle (n = 35) significantly improved patients’ headache symptoms before and after puncture. In addition, a controlled LP procedure significantly reduced the amount of unnecessary CSF loss (p

Guanine nucleotide exchange factors (GEFs) and guanine nucleotide-dissociation inhibitors (GDIs) regulate small GTPase proteins, which function as molecular switches in various signaling pathways, but their identification and functions in plants are not well understood. Using in-silico analysis and transgenic approaches, respectively, we dissected the evolutionary relationships and functions of all GEF and GDI genes in rice. Intron-exon distribution and phylogenetic analyses identified 30 GEF and 10 GDI genes in rice that shared close evolutionary relationships with other eukaryotes. Tissue-specific expression and co-expression analyses revealed that phylogenetically related genes had similar expression patterns. GEF and GDI genes were highly expressed in panicles, hulls, and stamens. Co-expression network analysis identified panicle and stamen-specific modules of co-expressed genes in both families. Mapping of these genes in known protein interactomes further identified two and one small G-protein sub-networks. A mutant library of GEF and GDI families was constructed by CRISPR knockout of each gene, and their genotypes and phenotypes were confirmed. Phenotype changes occurred with the mutation of only three genes (OsGEF5, OsGDI1, and OsGEF3). OsGEF5 and OsGDI1 single mutants exhibited significantly reduced height and longer and thinner grains, whereas OsGEF3 mutants had reduced grain length compared to the wild type. Haplotype and eGWAS analyses showed that natural variations in the three genes affected gene expression in reproductive tissues that were significantly associated with the phenotypic variation. BiFC assays demonstrated that GDI1 and GEF3 interacted with grain-size protein GS3, pointing to a role of these genes in the regulation of grain size and plant architecture connected to heterotrimeric G-proteins in rice.

Fractures and rock blocks are the essential components of rock mass, random fractured rock is the general manifestation of fractured rock mass, which is particularly significant in scale effect. To facilitate the tests, most of the previous studies on fractured rock mass were conducted on regular fractured rocks, which is not conducive to fully revealing the mechanical properties and failure characteristics of fractured rock mass. In this paper, the random fractured rock samples were produced with rock-like materials to investigate the fracture propagation and scale effect under compression-shear condition. Specifically, the samples were loaded by controlling the compression-shear angle to study the mechanical responses. In the test, speckle changes on the samples surface were recorded in real time, and the evolution of strain field was analyzed by digital image processing technology. Then, the internal relations among compression-shear angle, fracture distribution and crack propagation were discussed. Meanwhile, the failure modes of the random fractured samples with different compression-shear angles were summarized to reveal the influence of compression-shear angle on failure mode. Combined with PFC2D, the random fractured rock models of different scales were established to explore the mechanical characteristic variation, and the representative elementary volume of shear modulus was finally determined.

Artificial scent screening systems, inspired by the mammalian olfactory system, hold promise for fruit ripeness detection, but their commercialization is limited by low sensitivity or pattern recognition inaccuracy. This study presents a portable fruit ripeness prediction system based on colorimetric sensing combinatorics and deep convolutional neural networks (DCNN) to accurately identify fruit ripeness. Using the gas chromatography–mass spectrometry (GC-MS) method, the study discerned the distinctive gases emitted by mango, peach, and banana across various ripening stages. The colorimetric sensing combinatorics utilized 25 dyes sensitive to fruit volatile gases, generating a distinct scent fingerprint through cross-reactivity to diverse concentrations and varieties of gases. The unique scent fingerprints can be identified using DCNN. After capturing colorimetric sensor image data, the densely connected convolutional network (DenseNet) was employed, achieving an impressive accuracy rate of 97.39% on the validation set and 82.20% on the test set in assessing fruit ripeness. This fruit ripeness prediction system, coupled with a DCNN, successfully addresses the issues of complex pattern recognition and low identification accuracy. Overall, this innovative tool exhibits high accuracy, non-destructiveness, practical applicability, convenience, and low cost, making it worth considering and developing for fruit ripeness detection.

Incorporation of noncanonical amino acids into proteins holds great promise for altering structure and function of these proteins. Here the authors generate metabolically modified prokaryotic and eukaryotic cells that can biosynthesize sTyr and incorporate it into proteins in a site-specific manner.

Abstract We fabricated sulfur and nitrogen codoped cyanoethyl cellulose‐derived carbons (SNCCs) with state‐of‐the‐art electrochemical performance for potassium ion battery (PIB) and potassium ion capacitor (PIC) anodes. At 0.2, 0.5, 1, 2, 5, and 10 A g−1, the SNCC shows reversible capacities of 369, 328, 249, 208, 150, and 121 mA h g−1, respectively. Due to a high packing density of 1.01 g cm−3, the volumetric capacities are also uniquely favorable, being 373, 331, 251, 210, 151, and 122 mA h cm−3 at these currents, respectively. SNCC also shows promising initial Coulombic efficiency of 69.0% and extended cycling stability with 99.8% capacity retention after 1000 cycles. As proof of principle, an SNCC‐based PIC is fabricated and tested, achieving 94.3 Wh kg−1 at 237.5 W kg−1 and sustaining over 6000 cycles at 30 A g−1 with 84.5% retention. The internal structure of S and N codoped SNCC is based on highly dilated and defective graphene sheets arranged into nanometer‐scale walls. Using a baseline S‐free carbon for comparison (termed NCC), the role of S doping and the resultant dilated structure was elucidated. According to galvanostatic intermittent titration technique and electrochemical impedance spectroscopy analyses, as well as COMSOL simulations, this structure promotes rapid solid‐state diffusion of potassium ions and a solid electrolyte interphase that is stable during cycling. X‐ray diffraction was used to probe the ion storage mechanisms in SNCC, establishing the role of reversible potassium intercalation and the presence of KC36, KC24, and KC8 phases at low voltages.

Abstract Chemiluminescence (CL) imaging, as an excitation‐free technique, exhibits a markedly improved signal‐to‐noise ratio (SNR) owing to the absence of an excitation light source and autofluorescence interference. However, conventional chemiluminescence imaging generally focuses on the visible and first near‐infrared (NIR‐I) regions, which hinders high‐performance biological imaging due to strong tissue scattering and absorption. To address the issue, self‐luminescent NIR‐II CL nanoprobes with a second near‐infrared (NIR‐II) luminescence in the presence of hydrogen peroxide are rationally designed. A cascade energy transfer, including chemiluminescence resonance energy transfer (CRET) from the chemiluminescent substrate to NIR‐I organic molecules and Förster resonance energy transfer (FRET) from NIR‐I organic molecules to NIR‐II organic molecules, occurs in the nanoprobes, contributing to NIR‐II light with great efficiency and good tissue penetration depth. Based on excellent selectivity, high sensitivity to hydrogen peroxide, and long‐lasting luminescence performance, the NIR‐II CL nanoprobes are applied to detect inflammation in mice, showing a 7.4‐fold enhancement in SNR compared with that of fluorescence.

This paper investigates the bearing behavior of axially loaded rock socketed piles in limestone stratum embedded with a karst cavity beneath the pile. The pile foundation supporting a cross-river bridge located in a karst area in China is considered. Based on this project, three-dimensional finite element analyses are performed to capture the effects of pile length, pile diameter, limestone cohesion, and cavity roof thickness. Their impact on the bearing characteristics of the pile is comprehensively outlined through analysis of load-settlement curves, variations in pile bearing capacity, distributions of axial pile force and pile side friction, as well as contours of vertical ground and cavity roof displacement. It is found that the load-settlement curves exhibit the saltation type, based on which the pile-bearing capacity can be conveniently obtained. The pile bearing capacity increases nonlinearly with increasing the pile length, whereas almost linearly with an increase in the pile diameter, limestone cohesion, and cavity roof thickness. For the considered conditions, larger magnitudes of vertical ground displacements occur primarily surrounding the pile side in the pebble layer and at the pile bottom. This is attributed to the weakening effect of the karst cavity on the bearing capacity of the cavity roof. The achievements from this study are beneficial for the design optimization of rock socketed piles in karst areas.

Cracks affect the strength of rock masses and eventually threaten their stability in engineering. In order to study the fracture characteristics and mechanical properties of cracked rocks, uniaxial compression tests of pre-cracked granite samples with a central circular through hole were carried out by using MTS816 rock mechanics testing system. The inclination angles of different pre-cracks are 0°, 15°, 30°, 45°, 60°, 75°, and 90° respectively, and the influence of the crack stop hole near the crack tip on the failure behavior of pre-cracked samples is also considered. The results indicate that, compared with the intact sample, the peak strength of pre-cracked samples decreases significantly and is related to the pre-crack inclination angle. The failure mode of the sample varies with the pre-crack inclination angle, and the crack stop hole near the crack tip also has a certain influence on the crack growth to a certain extent. However, in terms of failure mode and its transformation law, the influence of central circular through hole and crack stop hole can be ignored. Generally speaking, the larger the inclination angle of the pre-crack, the more the total energy required for failure of the sample, and the more the stored elastic strain energy. Before the peak strength, the elastic strain energy of the sample is greater than the dissipated energy, after the peak strength, the dissipated energy gradually exceeds the elastic strain energy due to energy conversion. It is found that the pre-crack reduces the energy storage capacity of the sample, and the total energy is ultimately dominated by sample integrity. The dissipated energy rate increases first, then decreases, and finally increases again, the inflection points are the end of micro-crack closure and the peak strength, respectively. The crack stop hole changes the law of energy evolution to a certain extent, which can improve the ability of rocks to accumulate energy when designed at an appropriate position, so as to improve its load-bearing capacity in a certain range. The results display the mechanical properties of pre-cracked granite samples under uniaxial compression and are conducive to its application in engineering.

Deep excavations play an important role in the construction of urban infrastructures such as metro stations and high-rise buildings [...]

Hydrogels inevitably undergo dehydration, structural collapse, and shrinkage deformation due to the uninterrupted evaporation in the atmosphere, thereby losing their flexibility, slipperiness, and manufacturing precision. Here, we propose a novel bioinspired strategy to construct a spontaneously formed ‘skin’ on the slippery hydrogels by incorporating biological stress metabolites trehalose into the hydrogel network, which can generate robust hydrogen bonding interactions to restrain water evaporation. The contents of trehalose in hydrogel matrix can also regulate the desiccation-tolerance, mechanical properties, and lubricating performance of slippery hydrogels in a wide range. Combining vat photopolymerization three-dimensional printing and trehalose-modified slippery hydrogels enables to achieve the structural hydrogels with high resolution, shape fidelity, and sophisticated architectures, instead of structural collapse and shrinkage deformation caused by dehydration. And thus, this proposed functional hydrogel adapts to manufacture large-scale hydrogels with sophisticated architectures in a long-term process. As a proof-of-concept demonstration, a high-precision and sophisticated slippery hydrogel vascular phantom was easily fabricated to imitate guidewire intervention. Additionally, the proposed protocol is universally applicable to diverse types of hydrogel systems. This strategy opens up a versatile methodology to fabricate dry-resistant slippery hydrogel for functional structures and devices, expanding their high-precision processing and broad applications in the atmosphere.

The excavation of a super-large foundation pit is a greatly risky project in coastal water-rich silt strata, and it is of great significance to establish a numerical model to analyze and predict the stability of the foundation pit retaining its structure for safe construction. Based on a geological investigation report and key node monitoring data, the model parameters have been modified. Subsequently, the random field theory and numerical analysis were employed to proceed with deterministic analysis and uncertainty analysis, respectively. Using the uniform distribution method, Gaussian distribution method and the covariance matrix method to generate a random field model, finite difference software was applied to analyze the impact of spatial variability of cohesion and the internal friction angle on structural deformation. The study shows that the overall distribution of axial force is small on both sides and large in the center, and the axial force is larger near the shaped region. Due to the principle of “lever”, there is a tendency for the horizontal displacement of surrounding piles to partially rebound from the pit when the bearing platform pit is excavated. The spatial variability of the internal friction angle and cohesion has an important influence on the numerical value of the enclosure structure and surface deformation, and the variation pattern is basically unchanged.

Abstract A new concentrated ternary salt ether‐based electrolyte enables stable cycling of lithium metal battery (LMB) cells with high‐mass‐loading (13.8 mg cm−2, 2.5 mAh cm−2) NMC622 (LiNi0.6Co0.2Mn0.2O2) cathodes and 50 μm Li anodes. Termed “CETHER‐3,” this electrolyte is based on LiTFSI, LiDFOB, and LiBF4 with 5 vol% fluorinated ethylene carbonate in 1,2‐dimethoxyethane. Commercial carbonate and state‐of‐the‐art binary salt ether electrolytes were also tested as baselines. With CETHER‐3, the electrochemical performance of the full‐cell battery is among the most favorably reported in terms of high‐voltage cycling stability. For example, LiNixMnyCo1–x–yO2 (NMC)‐Li metal cells retain 80% capacity at 430 cycles with a 4.4 V cut‐off and 83% capacity at 100 cycles with a 4.5 V cut‐off (charge at C/5, discharge at C/2). According to simulation by density functional theory and molecular dynamics, this favorable performance is an outcome of enhanced coordination between Li+ and the solvent/salt molecules. Combining advanced microscopy (high‐resolution transmission electron microscopy, scanning electron microscopy) and surface science (X‐ray photoelectron spectroscopy, time‐of‐fight secondary ion mass spectroscopy, Fourier‐transform infrared spectroscopy, Raman spectroscopy), it is demonstrated that a thinner and more stable cathode electrolyte interphase (CEI) and solid electrolyte interphase (SEI) are formed. The CEI is rich in lithium sulfide (Li2SO3), while the SEI is rich in Li3N and LiF. During cycling, the CEI/SEI suppresses both the deleterious transformation of the cathode R‐3m layered near‐surface structure into disordered rock salt and the growth of lithium metal dendrites.

Abstract Background Infertility, an important source of stress, could affect sexual life. Extensive studies suggest that the incidence of sexual dysfunction is highly prevalent in infertile women. As the duration of infertility increases, the level of stress is also likely to increase even further, and this could aggravate psychological pain and cause sexual dysfunction. However, the effect of infertility duration on sexual health is unclear. Methods We conducted a case-control study in which 715 patients participated between September 1,2020 and December 25, 2020. We included patients diagnosed with infertility (aged between 20 to 45), who were divided into four groups according to their infertility durations: ≤ 2 years (Group I, n = 262), > 2 years but ≤ 5 years (Group II, n = 282), > 5 years but ≤ 8 years (Group III, n = 97), and > 8 years (Group IV, n = 74). A questionnaire survey on female sexual functions and psychological depression was administered to participants, and their female sexual functions and depression status were measured using the Female Sexual Function Index (FSFI) and Patient Health Questionnaire (PHQ-9), respectively. Results As the number of years of infertility increased, the PHQ-9 score as well as the incidence of psychological depression increased significantly (p < 0.05), but the total score of FSFI and those of its six domains/sub-scales were not significantly different among the four groups. An analysis of the relevant factors affecting sexual functions, using the multivariable logistic regression model, revealed that when the infertility duration was greater than 8 years, there was a significant increase in the incidence of sexual dysfunction [adjusted odds ratios (AOR) = 5.158, 95% confidence interval (CI): 1.935–13.746, P = 0.001], arousal disorder (AOR = 2.955, 95% CI: 1.194–7.314, P = 0.019), coital pain (AOR = 3.811, 95% CI: 1.045–13.897, P = 0.043), and lubrication disorder (AOR = 5.077, 95% CI: 1.340–19.244, P = 0.017). Conclusions An increasing infertility duration is a risk factor for the occurrence of sexual dysfunction. Hence, as the infertility duration increases, the incidence of female sexual dysfunction and psychological distress could also increase, especially when the infertility duration is more than 8 years.

Quercetin (QUE) is a component of the flavonoid family that shows various therapeutic properties, such as antioxidant effects. However, whether QUE affects porcine oocyte in vitro aging has not yet been investigated. Therefore, in this study, we applied various doses of QUE to freshly isolated porcine oocytes and found that 10 µM QUE improved the oocyte maturation rate in vitro, as reflected by the increased degree of cumulus cell expansion and first polar body extrusion. More importantly, we found that QUE reduced in vitro aging and improved the maturity level of porcine oocytes after another 24 h of culturing, accompanied by the upregulated expression levels of bone morphogenetic protein 15, growth differentiation factor 9, Moloney sarcoma oncogene, and cyclin-dependent kinase 2. In addition, we found that QUE treatment significantly reduced the intracellular reactive oxygen species levels, apoptosis, and autophagy and upregulated the expression levels of superoxide dismutase 2 and catalase in aged porcine oocytes. In addition, QUE restored impaired mitochondrial membrane potential and spindle assembly in aged porcine oocytes. Our findings demonstrate that QUE can protect porcine oocytes from in vitro aging by reducing oxidative stress and maintaining mitochondrial function.

The uplifting behaviors of existing tunnels due to overlying excavations are complex and non-linear. They are contributed to by multiple factors, and therefore, they are difficult to be accurately predicted. To address this issue, an extreme gradient boosting (XGBoost) prediction model based on Bayesian optimization (BO), namely, BO-XGBoost, was developed specifically for assessing the tunnel uplift. The modified model incorporated various factors such as an engineering design, soil types, and site construction conditions as input parameters. The performance of the BO-XGBoost model was compared with other models such as support vector machines (SVMs), the classification and regression tree (CART) model, and the extreme gradient boosting (XGBoost) model. In preparation for the model, 170 datasets from a construction site were collected and divided into 70% for training and 30% for testing. The BO-XGBoost model demonstrated a superior predictive performance, providing the most accurate displacement predictions and exhibiting better generalization capabilities. Further analysis revealed that the accuracy of the BO-XGBoost model was primarily influenced by the site’s construction factors. The interpretability of the BO-XGBoost model will provide valuable guidance for geotechnical practitioners in their decision-making processes.

To ensure the stability of the tunnel structure, this paper simulates the excavation process of shield tunneling in karst areas, and monitors the top of the arch, the bottom of the arch and the waist of the arch within the influence of the cave. It obtains the displacement and stress change laws under the influence of the upper cave and the lower cave. Finally, the main factors causing karst collapse in tunnels are explored through orthogonal tests. The results indicate that the displacement of the surrounding rock within the influence of the cave decreases and the stress increases. When the cavity and the tunnel reach the safety limit distance, the effect of the lower cavity on the stress around the tunnel is more obvious than that of the upper cavity. The results of the orthogonal test show that when the cavity is above the tunnel, the tunnel burial depth has the greatest influence on the stability of the surrounding rock; when the cavity is below the tunnel, the cavity height has the greatest influence on the stability of the surrounding rock.

The hydromechanical coupling behavior of rocks is widely present in the fields of rock mechanics and engineering studies. Analyzing and summarizing the relevant literature, the current status of experimental and coupling theory research on hydromechanical coupling is systematically described, the commonly used numerical simulation methods and their applications are briefly introduced, and the hydromechanical coupling problems in mining engineering, water conservancy, and hydropower engineering, slope engineering, tunneling engineering, and other fields are analyzed. Regarding the current status of studies on the hydromechanical coupling behavior of rocks, the test research aspect needs to further enhance the test studies on the triaxial shear permeability of rock material, and adopt a combination of macroscopic, fine, and microscopic methods to study the hydraulic coupling problems of rock materials from different scales. To couple theory, the traditional concepts are broken through, and new coupling theories and mathematical models are used to explain and solve the relevant practical problems. Meanwhile, the application of interdisciplinary approaches to solving coupling problems in the future is emphasized. In terms of numerical simulation and engineering applications, new large data algorithms are developed to improve the efficiency of simulation calculations. In addition, consideration should be given to the numerical simulation of coupling effects, the coupled rheological effects, and the coupled dynamic properties of rock masses under high-ground stress and high water pressure.

The settlement behavior of composite foundations plays an important role in the serviceability and stability of the subgrade or other infrastructures supporting the foundation. However, in water-rich flood plains, due to the complexity of the soft soil properties, the settlement behavior has not been well understood. The objective of this study is to investigate the effects of various key factors on the settlement behavior of composite foundations with deep mixed piles supporting highway subgrade in water-rich flood plains. The investigated subgrade is in operation, and the vehicle load is taken into account. The G347AH Project is considered in this study. Several typical models for predicting composite foundation settlements are discussed. By performing three-dimensional finite difference analysis, a comparison is made between the settlement behavior of the natural foundation and the composite foundation with deep mixed piles. Based on the single factor sensitivity analysis and the multi-factor orthogonal experimental design, the effects of pile length, pile diameter, pile spacing, pile elasticity modulus, cushion elasticity modulus, and cushion thickness on the composite foundation settlement are captured. It is found that among these factors, the degree of influence of pile length is superior. The composite foundation settlements predicted by the models agree well with the field-monitoring data, with the error being about 8.42% and 6.38%, respectively, at two monitoring sections. The research conducted in this paper can effectively reduce the probability of various settlement-related disasters occurring on highway subgrades in water-rich flood plains. Moreover, the research has important theoretical guidance for design optimization in terms of settlement control of highway subgrades in soft soil areas.

When large-scale wind power is connected to the power grid, the fluctuation and uncertainty in the wind power reduce the stability and accuracy of the grid's reactive voltage division results based on the electrical distance matrix and affect the grid's reactive power regulation. This paper proposes a grid reactive voltage partitioning method that considers the wind power stability and accuracy in a comprehensive manner. The wind power uncertainty and zoning results are characterized by the distribution of wind power forecast error intervals and changes in the zoning result nodes at different moments when the wind power is connected. Regarding volatility, according to the discretization of the probability distribution of the active power output at a certain time based on the wind power prediction, a calculation interval of the wind power output under a single cross-section is formed, and multiple sequential power flow sections within a long time scale are clustered and partitioned by an agglomeration hierarchical clustering method. Finally, an optimal zoning model of reactive voltage is established over a long time scale with the minimum comprehensive stability serving as the objective function. A simulation analysis of the improved IEEE39 node system shows that the partition combination can effectively increase the stability and accuracy of the reactive partitioning.

Accurate reactive load prediction can improve the accuracy and process of reactive power optimization for power grids and improve the control effect. The changes in the bus reactive load and active load are not synchronous, the base of the reactive load is small, nonlinear changes are abundant, and it is difficult to mine the inherent data trends. In view of the above problems, this paper proposes a method for predicting bus reactive loads based on deep learning. A bus reactive load prediction model is constructed based on a dual-input long short-term memory neural network to mine the detailed characteristics of active and reactive load data. Active and reactive loads are used as input and output data for the dynamic modeling of load time series data to form integrated forecasts of bus active and reactive loads. The experimental results show that this method can accurately predict the reactive power load of buses, and the prediction accuracy is better than that of time series and general long short-term memory neural network prediction models.

This paper describes recent advances in the effect of soil creep on the time-dependent deformation of deep braced excavation. The effect of soil creep is generally investigated using the observational method and the plain-strain numerical simulation method. The observational method is more applicable for deep braced excavations in soft clays constructed using the top-down method. The plain-strain numerical simulation method can be conveniently used for parametric analysis, but it is unable to capture the spatial characteristics of soil creep effect on lateral wall deflections and ground movements. The additional lateral wall deflections and ground movements that are generated due to the soil creep effect can account for as large as 30% of the total displacements, which highlights the importance of considering the effect of soil creep in deep braced excavations through soft clays. The magnitude of the displacements due to soil creep depends on various factors, such as excavation depth, elapsed period, unsupported length, and strut stiffness. Parametric analyses have indicated several effective measures that can be taken in practice to mitigate the detrimental effect of soil creep on the deformation of deep braced excavation. Based on the literature review, potential directions of the related future research work are discussed. This paper should be beneficial for both researchers and engineers focusing on mitigating the adverse effect of soil creep on the stability of deep braced excavations.

The rock or rock mass in engineering often contains joints, fractures, voids, and other defects, which are the root cause of local or overall failure. In response to most of the current constitutive models that fail to simulate the nonlinear fracture compaction deformation in the whole process of rock failure, especially brittle rocks, a piecewise constitutive model was proposed to represent the global constitutive relation of rocks in this study, which was composed of the fracture compaction empirical model and the damage statistical constitutive model. The fracture empirical compaction model was determined by fitting the expressions of fracture closure curves of various rocks, while the rock damage evolution equation was derived underpinned by the fracture growth. According to the effective stress concept and strain equivalence hypothesis, the rock damage constitutive model was deduced. The model parameters of the fracture compaction empirical model and damage statistical constitutive model were all calculated by the geometrical characteristics of the global axial stress–strain curve to guarantee that the models are continuous and smooth at the curve intersection, which is also simple and ready to program. Finally, the uniaxial compression test data and the triaxial compression test data of different rocks in previous studies were employed to validate the models, and the determination coefficient was used to measure the accuracy. The results showed great consistency between the model curves and test data, especially in the pre-peak stage.

As an advanced spatial technology, topography-sensing technology is comprehensive, macroscopic, and intuitive. It shows unique advantages for rock structure interpretation and has important guiding significance for the research of the shear performances of rock–mortar interface under cyclic load in rock mass engineering. In this paper, cyclic shearing tests combined with the shear surface topography-sensing technology are employed to investigate the evolution characteristics of the interface morphology and the strength deterioration of the rock–mortar interface. Primarily, mortar and three types of rocks are used to prepare different rock–mortar interfaces, which are then applied to cyclic shear loading under two constant normal stresses. Subsequently, the shear strength degradation and dilatancy characteristics of rock–mortar interfaces with varying shear times are discussed. In addition, on the basis of the non-contact three-dimensional topography-sensing technology, the apparent three-dimensional point–cloud coordinate information of rock–mortar interface before and after each shear loading is obtained, and the apparent three-dimensional topography parameters of rock–mortar interface are calculated, according to which the influences of normal stress and lithology on the topography of interface subjected to cyclic shearing loading are analyzed.

Under conditions of low or medium stress, rocks that are in the compression state exhibit perceivable nonlinear elastic characteristics. After a comprehensive review of the existing nonlinear elastic models of rocks and joints, we proposed a new unified nonlinear elastic model. This new model contains two parameters with clear definitions, namely, the initial elastic modulus Eni and the modulus change rate m. This model covers a variety of existing models, including the simple exponential model, BB model and two-part Hooke’s model, etc. Based on the RMT experimental system, a large number of uniaxial compression tests for dolomite, granite, limestone and sandstone were performed, and their nonlinear deformation stress‒strain curves were obtained and fit with the unified nonlinear elastic model. The results show that the rocks have obvious nonlinear elastic characteristics in their initial compression stage, and that the unified nonlinear elastic model is able to describe these phenomena rather well. In addition, an empirical formula for predicting the uniaxial compressive strength of the rock was constructed, corresponding to the unified nonlinear elastic model.

Recently discovered phase transition and elastic anomaly of compression-induced softening and heating-induced hardening (CISHIH) in group VB transition metals at high-pressure and high-temperature (HPHT) conditions are unique and interesting among typical metals. This article reviews recent progress in the understanding of the structural and elastic properties of these important metals under HPHT conditions. Previous investigations unveiled the close connection of the remarkable structural stability and elastic anomalies to the Fermi surface nesting (FSN), Jahn–Teller effect, and electronic topological transition (ETT) in vanadium, niobium, and tantalum. We elaborate that two competing scenarios are emerging from these advancements. The first one focuses on phase transition and phase diagram, in which a soft-mode driven structural transformation of BCC→RH1→RH2→BCC under compression and an RH→BCC reverse transition under heating in vanadium were established by experiments and theories. Similar phase transitions in niobium and tantalum were also proposed. The concomitant elastic anomalies were considered to be due to the phase transition. However, we also showed that there exist some experimental and theoretical facts that are incompatible with this scenario. A second scenario is required to accomplish a physically consistent interpretation. In this alternative scenario, the electronic structure and associated elastic anomaly are fundamental, whereas phase transition is just an outcome of the mechanical instability. We note that this second scenario is promising to reconcile all known discrepancies but caution that the phase transition in group VB metals is elusive and is still an open question. A general consensus on the relationship between the possible phase transitions and the mechanical elasticity (especially the resultant CISHIH dual anomaly, which has a much wider impact), is still unreached.

The risk evaluation indexes of goaf are multi-source and have complex mutual internal correlations, and there are great differences in the risk identification of goaf from different mines among the various influencing factors. This paper mainly focuses on principal component analysis (PCA) and the differential evolution algorithm (DE), while a multi-classification support vector machine (SVM) is adopted to classify the risks of goaf. Then, the K-fold cross-validation method is used to prevent the overfitting of selection in the model. After the analysis, nine factors affecting the risk identification of goaf in a certain area of East China were determined as the primary influencing factors, and 120 measured goafs were taken as examples for classifying the risks. More specifically, the classification results show that: (1) SVM has the useful ability of generalization, especially when solving the problems of overfitting, and it is easy to fall into the local minima under the conditions of small samples; (2) PCA is employed to realize the intelligent dimensionality reduction and denoising of multi-source impact indicators for goaf risk identification, which immensely improves the prediction accuracy and classification efficiency of the model; (3) after using the DE, the optimal solutions of the problems to be optimized are automatically obtained through the global optimization search mechanism, namely, the kernel function parameter, ‘γ’, and the penalty factor, ‘C’, of the SVM, which further verifies that the characteristics of clear logic, strong convergence, and good robustness can be found in the DE. As demonstrated, this method has the advantages of guiding significance and application value for goaf risk identification.

At present, the treatment of tailings is mostly carried out in the form of stacking in tailings ponds, resulting in a huge waste of mineral resources and a major threat to the environment and ecology. Using tailings instead of a part of the cement to make cementitious materials is an effective way to reduce the accumulation of tailings. In this paper, lead–zinc tailings-based cementitious materials were prepared by using lead–zinc tailings, fly ash, and ordinary Portland cement, and the effects of four factors on the mechanical properties of lead–zinc tailings, as well as fly ash content, cement content, and water–binder ratio were studied by orthogonal experiments. The corresponding relationship between the factors and the properties of cementitious materials was determined, and the optimization and prediction of the raw material ratio of lead–zinc tailings-based cementitious materials were realized. The test showed the ratio of raw materials to be at the lowest price ratio. Synchronously the ratio that meets the minimum strength requirements was predicted. When the proportion of fly ash:lead and zinc tailings:cement = 30:40:30 and the water–binder ratio was 0.4, the predicted compressive strength of the prepared cementitious material achieved 22.281 MPa, which meets the strength requirements, while the total content of lead–zinc tailings and fly ash was the highest at this time.

In this paper, model tests on a plain soil slope and a bamboo-rooted slope under slope top loading were carried out to analyze the slope surface displacement, the change in earth pressure, and the failure mode of the slope. Furthermore, the influence of rainfall on the deformation and mechanical properties of bamboo-rooted slope sliding was studied. The results show that: (1) the failure mode of the plain soil slope was block sliding failure, while the failure mode of the bamboo-rooted slope was progressive backward failure. (2) Under the slope top load, the slope displacement shows the rule that the top of the slope was large and the foot of the slope was small. The presence of bamboo rhizomes had a negligible effect on the slope displacement, but it significantly contributed to the sliding area’s increase. (3) Compared with the plain soil slope, the earth pressure in the area of the foot of the slope under the same level of the load was elevated more obviously by the bamboo-rooted slope, which indicates that bamboo rhizomes could play a specific role in reinforcing the slope. Still, the scope of its influence was limited and mainly concentrated in the shallow soil. (4) There was a significant increase in the displacement of the bamboo-rooted slope under rainfall conditions, and the magnitude of the upward slope earth pressure was small in the process of step-by-step loading. The test results may have important guiding significance for the in-depth study of the instability law and disaster prevention in bamboo forest areas.

Prussian blue is an iron-cyanide-based pigment steadily becoming a widely used electrochemical sensor in detecting hydrogen peroxide at low concentration levels. Prussian blue nanoparticles (PBNPs) have been extensively studied using traditional ensemble methods, which only provide averaged information. Investigating PBNPs at a single entity level is paramount for correlating the electrochemical activities to particle structures and will shed light on the major factors governing the catalyst activity of these nanoparticles. Here we report on using plasmonic electrochemical microscopy (PEM) to study the electrochemistry of PBNPs at the individual nanoparticle level. First, two types of PBNPs were synthesized; type I synthesized with double precursors method and type II synthesized with polyvinylpyrrolidone (PVP) assisted single precursor method. Second, both PBNPs types were compared on their electrochemical reduction to form Prussian white, and the effect from the different particle structures was investigated. Type I PBNPs provided better PEM sensitivity and were used to study the catalytic reduction of hydrogen peroxide. Progressively decreasing plasmonic signals with respect to increasing hydrogen peroxide concentration were observed, demonstrating the capability of sensing hydrogen peroxide at a single nanoparticle level utilizing this optical imaging technique.

The practice of deep-braced excavation in congested urban environments involves frequently buried pipelines, which can exert a significant effect on the performance of the excavation. The objective of this paper is to investigate the performance of a 12.5-m-deep-braced excavation spanned by two shallowly buried large-diameter pressurized pipelines. A suspension structure is installed within the excavation to protect the in situ pipelines during the construction. The excavation performance is investigated by performing a three-dimensional finite element analysis. The finite element method is verified based on the observations at the site. The results indicate that, as expected, the excavation support structures displace together with varying degrees of deformation toward the excavated area. The strut shear forces are found to be distributed axially in linear manners, while the strut bending moments are in symmetric manners. The benefit of using the proposed pipeline suspension structure is demonstrated. By using this structure, pipeline deformation can be well controlled, and the structural integrity and safety of the pipelines can be ensured. This benefit depends on the convenient operation in that the elevation of the cork base of the pipeline suspension structure is stably lowered during the construction process.

In this paper, a simplified prediction formula of ground settlement induced by deep foundation pit excavation is proposed, especially suitable for ground overloading near a foundation pit, such as embankment surcharge load, which is carefully considered via the means of load equivalence. The ground settlement induced by foundation pit excavation and embankment surcharge load is determined by the modified skewness prediction formula and the simplified Boussinesq solution, respectively, and it is assumed that no coupling effect exists between the two settlement sources. In addition, this paper improves the determination of the maximum settlement location by combining calculus and curve fitting, replacing the existing prediction formula which relies heavily on engineering experience to determine the maximum settlement point. The predicted value obtained using this method comes close to the measured value, and the deviation of the maximum surface settlement value is controlled within about 5% in the three cases introduced, of which the accuracy is higher than the existing prediction formula.

The escape of pedestrians in the subway station is hampered by floods created by heavy rain. In order to explore the critical flood level in a subway station so that pedestrians can escape safely, the case study of the Mingxiu Road subway station in Nanning, China, was conducted using numerical simulation techniques. In total, 30 groups of sample pedestrians with different walking speeds and numbers were randomly generated by the Monte Carlo method, and 3D simulation software was used for escape simulation. The simulated escape data were put into the SVM model, and the maximum pedestrian capacity and minimum speed of pedestrians were solved successfully with different conditions of the Mingxiu Road subway station. Then, a 1:1 contour model of the pedestrian was constructed to simulate the flood resistance of the pedestrian escaping at the minimum speed. The flood resistance and the friction force between the pedestrian and the ground were compared to calculate the critical escape flood level height, and the critical escape flood level height of an adult, child, and elder was 87.4 cm,75.5 cm, and 83.0 cm, respectively.

The cofferdam method is generally applied in the construction of underwater pier foundation in bridge engineering, and the pouring of bottom sealing concrete is one of the important links in the construction of the cofferdam. The bottom sealing concrete can prevent water seepage and balance the main body of the cofferdam, and its structural size and construction quality have a great influence on the above functions. Under the condition of large water level difference, it is difficult to determine the reasonable thickness of the bottom sealing concrete. There are few related studies in this field, and there is a lack of systematic summary of calculation theory. This work theoretically deduces the approximate solution of ultimate bending moment and ultimate stress of the bottom sealing concrete, introduces two different calculation methods, systematically summarizes the calculation methods of three kinds of ultimate stress, analyzes the calculation methods of ultimate bonding force, and uses ANSYS finite element software to simulate a specific bottom sealing concrete model, and compares it with the theoretical calculation results. The maximum stress obtained by the approximate solution is closer to the actual monitoring data than the traditional method, and the calculation method of the bonding force can be used to make a rough estimate.

In order to further explore the influence of reinforcement materials laying position on the dynamic characteristics of reinforced retaining walls, based on FLAC3D finite difference methods for solving nonlinear problems, established with the same size of the retaining wall in practical engineering, the reinforcement material’s relative position in the retaining wall for the normalized processing, under seismic load, and the panel under the conditions of different reinforcement arrangement were analyzed, and the horizontal displacement of slope, the vertical and horizontal earth pressures behind the wall, and the distribution of potential sliding surface were calculated. The relationship between the maximum horizontal displacement of the panel and the laying position of the reinforcement was fitted by MATLAB. The results show that the horizontal displacement of the panel is about 40% smaller when the upper layer of the reinforcement is arranged than that in the lower layer for step 1, and the horizontal displacement of the reinforcement in step 2 is about 30% lower than that in other conditions when the reinforcement is arranged at the top of the slope. The reinforcement arranged in the lower layer of step 1 and the upper layer of step 2 can minimize the wall top displacement. In step 1, the vertical earth pressure and horizontal earth pressure are 19% and 5% smaller than those in other conditions when the reinforcement is arranged near the middle and lower layer of the step. In step 2, the difference between vertical and horizontal earth pressure is not obvious, and the difference between the two conditions is controlled within 5%. At the same time, soil liquefaction and uplift occur under the action of earthquake. The position of sliding crack surface has no obvious regularity with the position of reinforcement, but the position of reinforcement at the step classification is obviously better than other conditions. The fitting formula can describe the relationship between the panel displacement and the position of the reinforcement well. The conclusions can provide a point of reference for practical engineering.

When a large amount of wind power is connected to the power grid, certain control methods need to be taken for wind turbines (WTs) so that WTs can respond to system frequency changes and maintain system frequency stability. Based on the frequency control method of a single doubly fed induction generator, a deloading power coordinated distribution method for frequency regulation by wind farms considering wind speed differences is proposed to better utilize the wind farm frequency regulation ability. A reasonable distribution of the deloading power of a wind farm for participation in grid frequency regulation to better utilize the wind farm frequency regulation ability. A quantitative calculation formula for the wind speed, total deloading power and single WT deloading power is established by using a variable parameter deloading power coordinated distribution coefficient based on the wind speed. The deloading power is distributed according to the wind speed of the WT units to adapt to the wind speed distribution differences between WTs in cluster wind farms and fully utilize the wind farm frequency regulation ability. A typical doubly fed induction generator (DFIG) wind farm is used as a simulation case. The experimental results show that the control strategy can distribute the output of each WT, improve the frequency response of the wind farm and enhance the frequency stability of the system.

This paper analyses the deformation and force behavior of a wood-piled island cofferdam based on the principle of equivalent bending stiffness. The horizontal deformation and bending moments in wood piles and the axial stress in tension bars on top of piles were both analyzed by the finite difference (FD) method. Except for the analysis of the cofferdam construction process, the influence of the pile length, the dam width, the tension bar interval, and the pile interval, among the commonly adopted parameters, were detailly examined in numerical simulations. In addition, a reinforced wood-piled cofferdam model by steel pipe piles has been established to quantify the effect of reinforcement. It was found that the dewatering inside the cofferdam was detrimental to cofferdam stability. The pile deformation reached maxima (roughly 0.6% of the pile length) at solidifying stage after dewatering. The changing trend of the cofferdam structure force within a safe district was consistent with the displacement. The dam width had a vital effect on the stability of the cofferdam, especially on the horizontal deformation. The steel pipe pile reinforcement scheme performed better in further deformation control, providing a new idea for island-type cofferdams with rigorous structural deformation control.