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The "regional advantage" hypothesizes that inference uncertainty/prediction error of geotechnical or geological properties at a target site (a site contains a group of records measured from different locations/depths using a variety of tests) can be smaller if we use a quasi-regional cluster (includes two or more database sites with geotechnical or geological properties similar to the target site) instead of the entire database. A tailored clustering enabled regionalization (TCER) framework has been proposed to verify this "regional advantage" hypothesis. TCER requires the target site should not be an outlier site relative to the database. However, it remains a challenge on how to detect an outlier site (or data group) from a database. In this paper, we modify the original TCER by introducing a novel outlier site detection step called maximum site similarity (MSS) into the original TCER. The capability of MSS is verified using synthetic and real examples. Additionally, three inference methods [e.g., probabilistic multiple regression (PMR), classical Bayesian model (CBM), and hierarchical Bayesian model (HBM)] are studied for the purpose of determining the optimal inference method for the modified TCER in terms of achieving the minimum inference uncertainty/prediction error with reasonable computational time. It is shown that the modified TCER with CBM outperforms other inference methods for the examples shown in this paper. • An efficient method that addresses a non-traditional class of outlier site detection problems is proposed. • The proposed outlier detection method is added to the original TCER framework for screening appropriate database. • A Shenzhen clay database named SZ-CLAY/7/3426 is compiled to validate the modified TCER framework. • Three inference methods are applied in the modified TCER framework and their inference uncertainties are compared. [ABSTRACT FROM AUTHOR]

This paper presents the slope dynamic response of jointed rock slopes containing three groups of typical joints and analyzes the effect of input harmonic frequency and joint density on the peak horizontal acceleration (PGA) of the slope surface under vertically impinging SV wave (shear vertical wave) excitation. First, the dynamic response of the slope surface of the bedding slope was investigated with a large-scale shaking table test, and the reliability of the numerical model was verified by the physical modeling. Then, a series of jointed rock slope models with different joint densities were established based on the three-dimensional discrete element software 3DEC. It is found that the natural frequency f n of the jointed slope decreases with the increase of joint density. The effect of excitation frequency f on the slope surface dynamic response of the jointed slope is stronger than that of joint density. The closer the f is to the f n , the stronger the slope surface and slope crest dynamic response is. Notably, taking f n as the critical value of f , the slope surface dynamic amplification mode of jointed slope can be divided into two types: when f ≤ f n , the acceleration amplification factor of X-direction (AAF-X) of the slope surface amplifies monotonically with increasing elevation; when f > f n , the AAF-X of the slope surface shows a fluctuated amplification pattern with the increase of elevation. The results of this paper show that in the seismic design of slope engineering, the influence of site conditions on the frequency spectrum characteristics of ground motion should be considered, and then the optimal design should be carried out. • Input frequency mainly controls the amplification effect on the slope surface. • Increase in joint density causes a decrease of the natural frequency of the slope. • Input frequency near the natural frequency makes the amplification effect strongest. • Input frequency divides seismic response of a jointed slope surface into two forms. [ABSTRACT FROM AUTHOR]

The construction of the deep-buried tunnels of the Sichuan-Tibet railway is facing severe rockburst disasters. Pressure relief boreholes and rock bolt support are effective methods for mitigating rockburst in hard rock. However, the mechanisms and differences in control effectiveness of these methods for different types of rockburst have yet to be revealed. This paper presents the results of two true triaxial unloading rockburst tests: Static-driven rockburst (static tests) due to excavation disturbance and dynamic-triggered rockburst (dynamic tests) due to adjacent tunnel excavation. The rockburst samples include intact granite, granite with a borehole (hole-granite), and granite with a negative Poisson's ratio bolt (bolt-granite). The mitigation mechanisms of the borehole and bolt were investigated in terms of rockburst intensity, failure patterns, and acoustic emission precursors. The results show that borehole and bolt inhibit the formation of a shear fracture plane during rockburst, with the bolt's inhibition effect being more pronounced. For static tests, borehole and bolt significantly reduce rockburst intensity, with the reduction being more significant for bolt-granite. The bolt mainly inhibits the propagation and penetration of shear microcracks. In contrast, the borehole promotes the propagation of shear microcracks. However, for dynamic tests, the rockburst intensity of bolt-granite is equivalent to that of intact granite, while the borehole enhances the rockburst intensity. The bolt inhibits the final buckling crack penetration in dynamic tests, while the borehole promotes slabbing. For static and dynamic tests, the borehole has little influence on precursor indicators, while the bolt increases the difficulty of precursor capture. Generally, the pressure relief borehole is more effective in controlling static tests, while bolt-reinforced support has advantages in dynamic test control. • Rockburst mitigation mechanisms using stress relief borehole and rock bolt support were revealed. • Static and dynamic rockburst tests were conducted on intact granite, hole-granite, and bolt-granite. • Pressure relief borehole is more effective in controlling static tests. • Boreholes and NPR bolts inhibit the formation of shear fracture during rockburst. • The borehole does not influence the optimal AE precursor, but the bolt increases the difficulty of capturing it. [ABSTRACT FROM AUTHOR]

Geomechanical studies of rock salt serve as the foundation for designing and ensuring the long-term stability of storage caverns. Research conducted in recent years has shown that rock salt exhibit highly variable mechanical parameters. Even macroscopically similar rock salt samples from the same formation have very different mechanical parameters in standard strength tests. In this paper, the effect of microfabrics on the mechanical behaviour of rock salt was studied using a uniaxial compression device with simultaneous observation under a microscope. The tests were carried out on rock salt samples, previously tested on standard uniaxial compression (UCS). Tested samples showed different strength values despite macroscopic similarity and similar anhydrite content. The tests revealed that the microfabrics, such as fluid inclusions and anhydrite crystals distributed along the halite grain boundaries, play a significant role in the strength of a rock salt sample. Four types of grain boundaries were recognized in both group of samples: (1) dominated by anhydrite crystals with a small number of fluid inclusions (FIs), (2) with FIs prevailing over anhydrite crystals, (3) only with FIs, and (4) without anhydrite crystals or FIs. The experimental uniaxial compression tests in microscale (mUCS) showed that the damage process is initiated by FIs activity at the halite grain boundaries and consists of three main stages. The samples dominated by anhydrite crystals at halite grain boundaries were characterised by the highest mUCS. Conversely, if FIs prevail at the grain boundaries the lowest mUCS values were registered. Therefore, anhydrite crystals located along halite grain boundaries influenced the mechanical behaviour and deformation process. On the contrary, anhydrite crystals dispersed within halite grains had no impact on failure and mechanical parameters. The experiment showed that apart from impurity content, the distribution of these impurities within halite grains should be examined during geomechanical evaluation of rock salt samples. Thus, the overall strength of rock salt samples determined in standard test results from the local variations of petrological features in micro- and macro scale. • Damage of rock salt is initiated on grain boundaries. • Strength of the rock salt is related to the type of the halite grain boundaries. • Anhydrite crystals located at the halite grain boundaries significantly increase rock salt strength. • Anhydrite crystals dispersed inside the halite crystals do not affect rock salt strength. • Fluid Inclusions located at the halite grain boundaries significantly decrease rock salt strength. [ABSTRACT FROM AUTHOR]

Co-seismic landslides can cause devastating consequences in seismically active mountainous regions. Rapid assessment of co-seismic landslides is essential in effective emergency response. A dilemma that hinders the assessment is the presence of a significant bias, either overestimating or underestimating the actual landslide hazard. To overcome this dilemma, this paper proposes a two-phase strategy that involves constructing a hierarchical Bayesian model augmenting data from a new earthquake with historical co-seismic landslide inventories. Our findings demonstrate that even with limited and evenly distributed co-seismic data from the new earthquake, it is possible to achieve an unbiased and accurate assessment. The two-phase strategy can facilitate the rapid and unbiased assessment of co-seismic landslides, thereby informing policy-making and resource allocation. • Co-seismic landslide assessment is often biased, either over- or underestimating landslide hazard. • A two-phase strategy is proposed based on the availability of co-seismic landslide data. • A hierarchical Bayesian model is implemented in the two-phase strategy. • The two-phase strategy enables unbiased and accurate co-seismic landslide assessment. • The rapid and unbiased assessment informs emergency response and resource allocation. [ABSTRACT FROM AUTHOR]

Geotechnical parameters required for estimating the maximum allowable annular pressure (P max) in horizontal directional drilling (HDD) are often empirically determined based on the results from the standard penetration test (SPT). Despite the benefits of SPT, its use in practice could be challenging as the geotechnical parameters determined based on SPT results vary largely depending on the choice made for SPT correlations. Such variability within the geotechnical parameters could result in a high degree of uncertainty within the estimates of P max in HDD. In this paper, an SPT-based algorithm is developed to study the variation in estimates of geotechnical parameters and P max due to the choice made for SPT correlation. Sensitivity analysis conducted using the SPT-based algorithm presents significant variations in both estimates of geotechnical parameters (relative ranges vary from 11% to 1516%) and P max (relative ranges vary from 10% to 1313%) for cases where the understanding of soil behavior and characteristics is insufficient. Error analysis conducted based on the errors in the geotechnical parameters determined using SPT correlations and the corresponding estimates of P max presents that the two types of errors are found closely related for most cases; however, exceptions also exist for the cases with the SPT correlations related to modulus of elasticity. Based on the results of the error analysis, suggestions for the use of SPT correlations are made for determining the input geotechnical parameters required for estimating the P max in HDD, and they are applied to a case study related to the hydraulic fracture experiments to demonstrate their usefulness in a real-world example. The case study presents high precision (R2 > 0.81) in the estimates of P max obtained by following the suggestions for the use of SPT correlations. In remark, the estimates of P max made based on some SPT correlations are found nearly equal to the measurements of annular pressure at hydraulic fracture, confirming that the SPT-based algorithm and the suggestions for the use of SPT correlations provided herein are reasonably reliable for estimating the P max in HDD. These results highlight the challenges with using empirically determined geotechnical parameters in the design of HDD and provide practitioners with valuable information for evaluating the stability of the HDD borehole. • Challenges with using empirical method for estimating P max in HDD is studied. • Sensitivity of P max estimate to the choice made for SPT correlation is analyzed. • An SPT-based algorithm for calculating P max is developed for the sensitivity analysis. • Errors in the SPT correlations and the corresponding estimates of P max are analyzed. • Based on the quantified results, suggestions for the use of SPT correlations are made. [ABSTRACT FROM AUTHOR]

Various predictive models for the seismically-induced displacement (D) of flexible slopes during shallow crustal earthquakes are available in the literature, but the model-to-model difference of predictions remains unclear. This paper conducts a comprehensive comparative study of ten representative D models based on scenario- and probabilistic-based displacement analyses. Explicit expressions are provided to implement the probabilistic displacement hazard approach, in which copula theory is utilized for deriving the joint occurrence probability of ground-motion parameters. A total of 6048 displacement hazard analyses are performed considering different earthquake and slope scenarios. It is found that the model-to-model difference generally becomes larger with increasing the natural period (T s) of a sliding mass, whereas the within-type difference among different coupled models is notably smaller than that of the decoupled models. The coupled-type models generally result in smaller total variability of D as compared to the decoupled-type models. Meanwhile, the coupled models tend to, on average, yield larger (or smaller) hazard-consistent D than the decoupled models for T s larger (or smaller) than an intersection period T s,inter , though the difference between the two model types diminishes as T s approaches zero. The effects of ground-motion model selection and ground-motion parameter correlation are also discussed. This study could hopefully provide insights into the displacement model selection for the seismic slope performance assessment and regional landslide hazard mapping. • Comparative studies of ten slope displacement models are conducted. • Copula-assisted probabilistic displacement hazard procedures are presented. • Models yielding lower- and upper-bound displacement hazards are identified. • Relative difference between decoupled and coupled predictions is closely related to T s. • Within-type difference among coupled models is smaller compared to decoupled models. [ABSTRACT FROM AUTHOR]

Plowing refers to the phenomenon by which a landslide displaces and pushes the path material forward. Despite its importance in shaping the dynamics of many rapid flow-like loess landslides, the mechanism of plowing is not fully understood. Therefore, this paper presents an improved numerical model based on the material point method (MPM). This model takes into account the interactions between the landslide mass and the path material. The reliability of this model was validated by simulating two granular column collapse experiments involving interaction with an erodible mass. The model was then applied to analyze the plowing dynamics of the Ximiaodian loess landslide in Jingyang County, Shaanxi Province, China. A series of well-designed simulations were conducted to investigate this specific landslide event, contributing to a deeper understanding of the plowing phenomenon in loess landslides. The simulation results show that our model can satisfactorily simulate the plowing process of the Ximiaodian landslide. The plowing process of a rapid-flow loess landslide is proposed to consist of four distinct stages: 1) the collision stage, when the landslide strikes the terrace, resulting in the bending of its strata; 2) the shear failure stage, characterized by significant plastic shear deformation within the bent strata, resulting in the formation of multiple shear failure planes; 3) the steady plowing stage, during which the deformation structure in the affected terrace stabilizes and plowing continues in a steady pattern; and 4) the stopping stage, when the propagation of the disturbed terrace gradually stops. Furthermore, the disturbed terrace zone exhibits three distinct deformation structures. In the rear part, a stable zone develops where the terrace layers are compressed. However, due to the compressive forces exerted by the overlying loess, no significant shear deformation is observed. The middle part is the shear failure zone, characterized by the formation of multiple shear failure planes. The front part is the upheaval zone, where the terrace layers are slightly bent and tilted. • An improved MPM model is proposed to simulate the plowing process of rapid flow-like landslides. • The plowing mechanism of a real loess landslide is analyzed by the MPM model for the first time. • The plowing process of a rapid flow-like loess landslide consists of four stages. • Three distinct deformation structures are formed in the disturbed terrace zone during the plowing process. [ABSTRACT FROM AUTHOR]

In this paper, a well designed experimental study comprising undrained cyclic triaxial and bender element tests was carried out on five sand-silt mixtures with three grain size ratios (R d) and three sand uniformity coefficients (C us). The results reveal that at given fines content (FC) and void ratio, the liquefaction resistance (CRR) of the mixtures decreases as R d increases from 9.7 to 27.8 or C us from 1.50 to 4.46, and the CRR of the mixture at the highest R d or C us becomes as low as nearly 50% of that at the lowest R d or C us. The equivalent relative density (D r *) based on the binary packing theory can be utilized to capture the coupled effects of host sand gradation and FC on the CRR of sand-silt mixtures. A novel finding is that a universal relationship exists between the liquefaction resistance and the shear modulus normalized by the minimum void ratio function of host sand (G N ') for different FCs, initial effective confining pressures, sample preparation methods (SPMs), and host sand gradations. Based on the comprehensive laboratory test data, the empirical CRR 15 - G N ' correlation is proposed and further adjusted for the field liquefaction triggering analysis based on the shear wave velocity (V s). Soil can be considered non-liquefiable when its equivalent shear wave velocity exceeds 225 m/s or the applied cyclic stress ratio (CSR) is below 0.088. Comparisons with the previously established liquefaction triggering boundary curves validate the applicability of the proposed curve for initial evaluation of the liquefaction resistance of sandy soils, indicating laboratory studies can complement in-situ investigations for V s -based liquefaction assessment. • CRR 15 decreases with the increasing R d or C us at given e and FC. • CRR 15 can be well characterized by D r * regardless of sand gradation and FC. • A unique CRR 15 - G N ' relation exists for varying FCs, σ 0 ', SPMs, R d , and C us. • The new V s -based field liquefaction triggering boundary curve is proposed. • Laboratory tests can complement the in-situ V s -based liquefaction assessment. [ABSTRACT FROM AUTHOR]

The migration of fluids, such as the dissociation of natural gas hydrates, can affect the stability of the seabed and even induce submarine geological disasters and change the marine environment. The migration of fluids in sediments depends on its permeability properties. Therefore, it is crucial to investigate the sediment permeability and its influencing factors. This paper investigates the particle size, porosity, pore size distribution, and permeability of surface clay-bearing sediments in the Shenhu Area of the South China Sea by physical property tests, computed tomography (CT) scanning tests, constant rate of strain (CRS) consolidation tests, and nuclear magnetic resonance (NMR) tests. The permeability of the surface sediments in the Shenhu Area ranges from 3.32 × 10−15–6.76 × 10−14 m2. The pore size mainly ranges between 10−5 and 10−1 mm, exhibiting a bimodal distribution with peaks from 10−4 and 10−2 mm. The increase in clay content leads to enhanced permeability due to the bimodal distribution of pore sizes, which will cause the enlargement of pores. As the pore size increases, the sediment permeability also increases. Sediment permeability linearly decreases with increasing effective axial stress and deformation due to compression of the pore space. Additionally, a new model for calculating permeability with different sediment properties is established, which improves the accuracy of permeability calculations for clay-bearing sediments compared to previous research. The findings of our study can provide a reference for exploring the influence of sediment parameters on fluid migration mechanisms in clay-bearing sediments. • The bimodal distribution of pore size affects the correlation between clay content and permeability. • Variation of permeability has linear relationships with deformation and effective axial stress. • A new model is established to more accurately calculate the permeability of clay-bearing sediments. [ABSTRACT FROM AUTHOR]

In this paper the use of ER measurements in soils in the context of biocementation, is investigated considering its use as an indicator of treatment efficiency measured trough the presence of biocement, or to provide information about the presence of chemical by-products during or after final washing operations. The electrical resistivity of a slightly biocemented sand was analyzed on a laboratory scale test conceived to reproduce field measurements conditions such as varying degrees of saturation and the presence of chemical by-products in the pore fluid. The results confirmed that, independently from the degree of saturation, the nature of the pore fluid was the parameter that affected most the electrical resistivity measurements, and the presence of calcium carbonate affecting soil structure was detected only after removal of the treatment by-products by a complete final soil washing using water. From a practical point of view this non-destructive technique is more adequate to be used mainly at the end of the treatment, to check that complete soil washing has occurred, rather than checking the presence of bio-cement specially if the amount precipitated is not very high as it was the case of the tests performed. • During the biocementation process by-products are generated (ammonium & chlorides). • By-products must be removed from the soil to ensure environmental sustainability. • ER measurements allow checking that all by-products were removed from the soil. • When removed, is possible to detect the effect of biocement on ER measurements. [ABSTRACT FROM AUTHOR]

The sealing of fine aperture fractures in geological repositories is an important consideration for long-term sealing integrity. Common grouting materials have some disadvantages, such as low sealing efficiency, environmental pollution, etc. Microbially induced calcium carbonate precipitation (MICP) has been proposed as a potential solution for sealing fine fractures. In this paper, the microbially mediated fine fracture mineralization sealing process was investigated by using a designed visual test device. The flow channel evolution and fracture transmissivity reduction during the sealing process were systematically monitored and analysed. Based on the experimental results, a sealing pattern of microbially mediated rock fracture mineralization was proposed. In addition, the influence of biomineralized floc particles formed by different bacterial concentrations on the critical sealing threshold of fracture was discussed. The results show that the sealing pattern can be divided into four stages: (a) flow channel formation; (b) preferred channel blocking; (c) finer channel blocking; (d) filtration zone formation. The four sealing stages correspond to different fracture transmissivity reduction trends, and the majority of transmissivity reduction occurs in stage III. However, the transmissivity decreases rapidly only after the preferred channels are blocked, which indicates that the critical threshold of sealing fracture is reached. The critical sealing threshold is mainly attributed to two factors: biomineralized floc particle size and fracture aperture. Larger floc particles and finer aperture are more likely to reach the critical sealing threshold, improving the sealing efficiency of fractures. It is crucial to further study the interaction between the biomineralized floc particle sizes and the fracture aperture at the critical sealing threshold to optimize the application of MICP-grouting in rock fine fractures. • The sealing process and mechanism of MICP-grouting on rock fine fractures were studied. • A sealing pattern of microbially mediated rock fine fracture mineralization was proposed. • The critical sealing threshold of the fracture is the key factor affecting the fracture transmissivity reduction by MICP-grouting. [ABSTRACT FROM AUTHOR]

The collapse of glacial, permafrost, and ice-rich moraine slopes in high-altitude mountainous areas not only threatens downstream residents and infrastructure but also displaces ice mass to lower and warmer elevations, accelerating glacial ablation to some extent. Despite being considered rare, ice-rich slopes collapse more frequently than commonly thought due to climate change. For example, two adjacent mountain glaciers in the Aru Range of the Tibetan Plateau, characterized by large volumes (68 × 106 m3 and 83 × 106 m3, respectively) and low surface slope angles (12.3° and 12.9°, respectively), collapsed surprisingly in 2016. While the mechanisms behind these collapses have garnered broad attention, the ability to quantitatively assess the instability of ice-rich slopes remains limited due to the complex interplay of multi-physical processes. Taking the Aru glacier collapses as reference cases, this paper presents a conceptual model, implemented through coupled thermo-hydro-mechanical simulation, to evaluate the stability of high-altitude ice-rich slopes due to climate change, rainfall and ice ablation. Results indicate that the methodology captures the effects of temperature change, rainfall and meltwater on the instability events well, demonstrating promising potential in evaluating potential collapse zones of ice-rich slopes similar to the Aru glaciers. Furthermore, the role of climate change in the well-known Aru events is demonstrated using a state-of-the-art global climate reanalysis dataset. Findings reveal that the increase in liquid water infiltrating the Aru glaciers since 2010 was a critical factor leading to the instability events. • A conceptual model is proposed to analyse the stability and collapse zones of ice-rich slopes. • The modelling elucidates the causes of twin collapses of the Aru glaciers. • Results contribute to ice-rich slope instability prediction and associated disaster risk management. [ABSTRACT FROM AUTHOR]

In this study, we introduce a novel method for estimating undrained shear strength (C u) by incorporating SPT depth. A comprehensive dataset of 328 data groups from locations in Alberta was employed to investigate the correlation between C u and various factors such as Atterberg limits, moisture content, sampling depth, and both field SPT numbers (N) and modified SPT numbers (N 60), utilizing Pearson Correlation Analysis. The performance of the new approach was evaluated using metrics such as mean absolute error (MAE), mean square error (MSE), root mean square error (RMSE), mean absolute percentage error (MAPE), and coefficient of determination (R2). Comparative assessments of the new approach were made with existing approaches for C u estimation. Furthermore, the proposed approach was applied to calculate C u based on borehole information and moisture content data from 702 projects in Alberta, and its validity was verified against published information. The results demonstrate that the new approach yields C u calculations with comparatively small discrepancies. This paper presents a reliable tool for estimating the average C u of clay till in Alberta in a preliminary design state, with potential applicability to other regions as well. • Propose an innovative approach to calculate Cu based on SPT, D and w n. • A large dataset was employed to evaluate the existing model and develop a new one. • Develop a map of Cu of clay till based on data from702 projects in Alberta. • Review and reevaluate the current soil classification matrix. [ABSTRACT FROM AUTHOR]

Seismic fragility analysis is one probabilistic method that represents the conditional probabilities of exceeding different predetermined damage states for various given earthquake hazard levels, which is the essential part of probabilistic seismic risk assessment. It has gained much popularity recently because much more comprehensive and richer results than traditional probabilistic methods can be provided. The classical seismic fragility analysis of slopes is always performed through analytical approaches. In the present study, a novel seismic fragility analysis framework combined with shaking table model test results is proposed for probabilistic seismic performance and risk assessment of slopes. The shaking table model tests of a rock slope reinforced by pile-anchor structures were firstly performed subjected to a suite of real earthquake records with different intensity levels. Subsequently, the seismic responses from shaking table model tests were then gathered for the optimal analysis to determine the optimal engineering demand parameter (EDP) and earthquake intensity measure (IM) for seismic fragility analysis of slopes. At last, the identified most appropriate IM and EDP were selected to construct the scalar-valued fragility curves, vector-valued fragility surfaces and fragility surfaces considering acceleration elevation amplification effect by the proposed framework. The results indicate that using single IM to construct scalar-valued fragility functions may result in different failure probabilities depending on the chosen earthquake IM. The vector-valued fragility surfaces provide more information than ordinary fragility curves, and lead to more proper and realistic evaluations of seismic hazard of slopes. The methods and results presented in this paper also provide the basis for the probabilistic seismic risk and loss assessment of earthquake-induced slope geological disaster. • A novel seismic fragility analysis framework of slopes combined with the data from shaking table model tests is proposed. • The optimal EDP and earthquake IM for scalar- and vector-valued fragility analysis of slopes are identified. • The fragility surfaces of a slope considering acceleration elevation amplification effect are constructed. [ABSTRACT FROM AUTHOR]

Rail and road embankments constructed on peatlands are subjected to significant challenges due to the high compressibility of peat. They are, therefore, susceptible to considerable settlement following construction. Accurate and timely monitoring of such embankments is important in order to enable proactive intervention strategies and to avoid failures. Multi-temporal Synthetic Aperture RADAR Interferometry (MT-InSAR) techniques applied to satellite-derived SAR data have been shown to be effective for remotely measuring and monitoring the deformation of civil engineering infrastructure. This paper presents a comprehensive approach, involving MT-InSAR supported by local geophysical and geotechnical information, for the detection and investigation of the movement of a railway embankment constructed on peatland. The Small Baselines approach, implemented in StaMPS (referred to as StaMPS-SB), was performed to measure long-term deformation of the embankment in vertical, horizontal east-west and satellite line-of-sight (LOS) directions. In this regard, a Sentinel-1 A/1B dataset composed of 362 descending images, acquired from 2015 to 2022, was analysed to measure LOS displacement. Also, 282 Sentinel-1 A/1B images of both ascending and descending tracks, collected from 2017 to 2022, were analysed to obtain vertical, horizontal and LOS displacements. According to the results, the maximum ground motion rate along the LOS direction was −29 mm/year for the period from 2015 to 2022. However, from 2017 to 2022, this value was about −25 mm/year and − 22 mm/year for descending and ascending tracks, respectively. During this period, the maximum motion rate obtained was −23.1 mm/year in the vertical direction. Moreover, horizontal movement up to −10 mm/year was observed in the westward direction and + 7 mm/year in the eastern direction. We used in-situ data to support corroborate and improve our interpretation of the InSAR results. In this context, peat thickness profiles, records of tamping activities and interpretations of the railway ballast base from ground penetrating radar data, were employed. The in-situ data revealed that the embankment section exhibiting the greatest vertical motion detected by InSAR corresponds closely to the thickest section of railway ballast, the zone of greatest number of tamping activities and the deepest section of peat. As such, this case study highlights how remote detection of embankment motion, coupled with targeted in-situ investigation, can underpin proactive intervention to improve safety. • Historic displacements of a railway embankment constructed on peat measured by StaMPS-SBAS InSAR technique. • Sentinel-1 A/1B data spanning several years were analysed to measure vertical, horizontal, and line-of-sight displacement. • Geophysical and geotechnical information supported and enhanced the interpretation of InSAR results. • Remote monitoring combined with in-situ measurements provided insight into differential settlement of the embankment. [ABSTRACT FROM AUTHOR]

Classical clustering (CC) normally divides a database into a predetermined number of fixed clusters before assigning each target site into one of these clusters to build a quasi-local model. Because the range of target sites is much larger than the range of clusters, it is possible that the identified cluster contains database sites that are weakly correlated to some assigned target sites, especially when these target sites are located near the cluster boundaries. The existence of weakly correlated sites in the cluster may make the quasi-local model less effective in predicting soil properties at the target site. This paper proposes a Tailored Clustering Enabled Regionalization (TCER) framework that can minimize the inference uncertainty at a target site. It mainly consists of two parts: (1) a site similarity measure to quantify the similarity between database sites and the target site and (2) a novel tailored clustering (TC) approach to identify the optimal cluster (called quasi-regional cluster) of database sites with the highest site similarity measures. In comparison to the traditional TC, the novel TC does not require users to specify a site similarity threshold that divides database sites into those within the cluster and those outside the cluster. Finally, a hierarchical Bayesian model is applied to the quasi-regional cluster (rather than the entire database) to infer geotechnical/geological properties at the target site. The capability of TCER is verified using synthetic and real examples. It is shown that the proposed TCER is computationally efficient and can reduce inference uncertainty. • An inter-dataset similarity measure is modified to make it suitable for comparing the similarity between two sites. • A novel clustering approach is proposed for identifying a cluster that is highly correlated to the target site. • A tailored clustering enabled regionalization framework is proposed for reducing inference uncertainty of a target site. [ABSTRACT FROM AUTHOR]

An accurate and reliable 3D engineering geological model (expressed herein as a 3D litho-stratigraphic model) is essential for designing slopes, underground structures, and tunnels to reduce the risk of failure. Due to budget constraints, subsurface investigations with traditional methods (e.g., boreholes and geophysical prospecting) are often limited in quantity. Insufficient investigation often leads to inadequate litho-stratigraphic data that can degrade the reliability of the developed 3D litho-stratigraphic models. To this end, LiDAR, which can collect topographic data more efficiently and economically, may complement traditional geological investigations for developing litho-stratigraphic models. However, the task of integrating the subsurface geological data and LiDAR data to create 3D litho-stratigraphic models for engineering applications is challenging. This paper proposes a methodology that combines LiDAR-derived geological data (Type I data herein) and borehole data (Type II data herein) to develop realistic 3D litho-stratigraphic models. To demonstrate the methodology, we took a 1.2 km × 1.2 km area with sedimentary rocks in northern Taiwan as the study area. Under the assumption that the strata are parallel, we first fitted Type I data to a surface regression model (a polynomial mathematical model). Then, we incorporated Type II data into the regressive process to develop the desired 3D model. Comparing the former model (based on Type I data) with the latter model (based on Type I + II data) through a Root-Mean-Squared-Error (RMSE) analysis, it was found that the RMSE of the latter model decreased significantly, indicating a decrease in the error between the developed litho-stratigraphic model and the 'ground truth.' To verify this finding, we compared the newly developed 3D model with the 'known' geological cross-section of the Qidu Tunnel constructed nearby. The results indicated that the distribution of the primary sandstone strata uncovered from the previous Qidu Tunnel project and those projected by the newly developed 3D model was highly consistent. Thus, this study demonstrates that LiDAR data combined with a few borehole data has the potential to create reliable and accurate 3D geological models, providing an effective solution for obtaining 3D geological information at the scale of engineering applications with limited boreholes. Finally, the proposed modeling approach is further demonstrated through two hypothetical engineering application cases. • 3D litho-stratigraphic modeling using LiDAR and limited borehole data. • Modeling in a dip-slope terrain was verified through ground truth along a tunnel. • Combination of LiDAR and borehole data can greatly improve the model reliability. • Precise borehole data and extensive range of LiDAR data complement each other. [ABSTRACT FROM AUTHOR]

This paper aims to develop an improved CRR - V s1 characterization model for soil liquefaction evaluation for binary mixtures via a series of DEM simulations of drained monotonic tests, undrained cyclic tests and shear wave velocity measurements. The contributions of different contact types to the mean effective stress of binary mixtures depend mainly on the coarse content and to a negligible extent on the confining pressure and particle size ratio. The threshold coarse content, denoting the mechanical behavior transition of binary mixtures, can be identified either by the macroscopic evolutions of critical state lines or the distributions of microscopic contact forces. The skeleton reinforcement factor m decreases approximately linearly with the increase of coarse content, while the skeleton supporting factor b exhibits a nonlinear decrease relationship with coarse content, both of which are influenced by particle size ratio. Under the condition of the same equivalent skeleton void ratio, a V s -correction function and a CRR -correction function are introduced to consistently describe the nonlinear coarse content effects on the shear wave velocities and liquefaction resistances of binary mixtures. The improved CRR - V s1 characterization model with consideration of coarse content is established by relating the shear wave velocity and liquefaction resistance of binary mixtures to those of the base fine or coarse matrix using the concept of equivalent skeleton void ratio. Application of the proposed characterization model to real geotechnical materials requires laboratory element tests to determine the V s -correction function and the CRR -correction function, together with the CRR - V s1 benchmark curve of the base fine or coarse matrix. • The threshold coarse content of binary mixtures is identified by DEM simulation. • The equivalent skeleton void ratio depends on coarse content and particle size ratio. • The CRR - N l curves for binary mixtures rotate clockwise due to the reinforcement effect of coarse particles. • The improved CRR - V s1 characterization model for liquefaction resistance evaluation of binary mixtures is proposed. [ABSTRACT FROM AUTHOR]

Desiccation cracks in soils pose risks to the serviceability and safety of geotechnical infrastructure worldwide. This paper aims to investigate the potential of superabsorbent hydrogels (SAH) as innovative soil amendment to mitigate soil drying effects and cracking. Laboratory tests were conducted on an initially saturated silty soil treated with different types and dosages of SAH. Desiccation cracking tests, shrinkage tests, and water retention tests were performed to analyse the cracking process, evaporation rate, and retention properties. The tests were integrated with micro-CT scan analyses to observe changes in soil fabric due to the SAH addition. The results indicate that SAH particles serve as internal water reservoirs, extending the normal shrinkage stage and maintaining higher suctions without significant desaturation, in comparison to untreated soil. The addition of SAH reduces the evaporation rate, particularly at a dosage of 0.1%. The progression of cracking occurs at suctions below the air entry value, and the inclusion of SAH reduces the rate of crack development. These findings highlight the need for additional research on SAH as a promising soil treatment for geotechnical applications. • Superabsorbent hydrogels (SAH) can delay soil desiccation cracking. • SAH contribute to maintaining higher suction without significant desaturation. • Addition of SAH reduces the evaporation and cracking rates. • Fabric changes induced by SAH cavities may influence cracking initiation. • SAH show potential as soil treatment to enhance soil response upon drought. [ABSTRACT FROM AUTHOR]

Effective detection of groundwater in landslide areas is crucial for landslide monitoring. The magnetic resonance sounding (MRS) method is a geophysical technique that can directly detect groundwater. However, its application in landslide groundwater monitoring is often hindered by the complex topography of landslides. This paper presents an MRS framework that accounts for the impact of landslide topography on groundwater detection. The framework includes the use of drone photogrammetry to obtain high-precision topography data and real-time kinematic equipment to acquire the coordinates of key points along the MRS coil. A three-dimensional finite element model is then constructed to calculate the alternating magnetic field generated by the MRS coil and the kernel function required for MRS inversion. Two typical landslide topography models—terrace and gully—are constructed and analyzed using numerical simulations. The results indicate that landslide topography significantly impacts the quality of groundwater information retrieved by MRS in both one-dimensional and two-dimensional inversions, affecting the accurate detection and identification of infiltration surfaces, sliding zone water, and bedrock surfaces. If accurate topography data are obtained and appropriate kernel functions are calculated, the accuracy of the inversion can be greatly improved. An example of using the MRS method to detect groundwater in a complex landslide in the Three Gorges Reservoir area of China is then presented. The MRS inversion results that consider landslide topography are confirmed using borehole data, electrical resistivity tomography detection results, and on-site drainage tunnel investigations. The water-content distribution inside the landslide body is obtained, providing information helpful to define sliding zones in multi-level landslides. The proposed landslide MRS detection framework makes it possible to apply MRS methods to the detection of landslide groundwater distribution, analysis of seepage fields, and discrimination of landslide geological structures. • Landslide topography significantly affects the quality of groundwater information retrieved by MRS. • Obtaining accurate topography data and calculating appropriate kernel functions improve MRS inversion results. • MRS field work on a complex landslide is validated by borehole data, ERT, and on-site drainage tunnel investigations. [ABSTRACT FROM AUTHOR]

Reservoir operations can induce massive landslides due to the regional hydraulic effects, where pile reinforcement is a widely used stabilization method. The 1-g physical modeling is one of the most common methods used to study reservoir landslides and their pile reinforcement, while some limitations have been presented in the method, slowed its development down, and adverse to novel results. This paper presents a systematic review and discussion of 1-g physical modeling relevant to pile-reinforced reservoir landslides. Various aspects, from the theoretical basis (i.e., principle of similitude) to experimental details (i.e., model construction, test technique, and data acquisition and interpretation), are investigated. The principle of similitude and application in the physical modeling of pile-reinforced reservoir landslides are discussed. Factors causing distortions in a 1-g physical landslide model are discussed, and measures for distortion control are proposed. The significance and limitations of the physical model construction and obtained data are analyzed, and some improvements are proposed. Based on previous work and our experience, the lessons learned in the technical aspects of 1-g physical modeling are presented along with recommendations for the physical modeling of landslides, especially those reinforced with piles. • A strategy of distortion compensation in 1-g physical modeling is provided as a supplement to the principle of similitude. • The lessons in technical aspects of 1-g physical modeling of reservoir landslides and pile reinforcement are discussed. • The displacement and pressure data limitations are analyzed and its improvements are proposed. [ABSTRACT FROM AUTHOR]

In geotechnical engineering, an appreciation of local geological conditions from similar sites is beneficial and can support informed decision-making during site characterization. This practice is known as "site recognition", which necessitates a rational quantification of site similarity. This paper proposes a data-driven method to quantify the similarity between two cross-sections based on the spatial variability of one soil property from a spectral perspective. Bayesian compressive sensing (BCS) is first used to obtain the discrete cosine transform (DCT) spectrum for a cross-section. Then DCT-based auto-correlation function (ACF) is calculated based on the obtained DCT spectrum using a set of newly derived ACF calculation equations. The cross-sectional similarity is subsequently reformulated as the cosine similarity of DCT-based ACFs between cross-sections. In contrast to the existing methods, the proposed method explicitly takes soil property spatial variability into account in an innovative way. The challenges of sparse investigation data, non-stationary and anisotropic spatial variability, and inconsistent spatial dimensions of different cross-sections are tackled effectively. Both numerical examples and real data examples from New Zealand are provided for illustration. Results show that the proposed method can rationally quantify cross-sectional similarity and associated statistical uncertainty from sparse investigation data. The proposed method advances data-driven site characterization, a core application area in data-centric geotechnics. • A novel method is proposed for quantifying 2D cross-sectional similarity of soil property spatial variability • An efficient formulation of 2D auto-correlation function is derived for a unified representation of 2D spatial variability • The challenges of sparse investigation data, non-stationarity, and inconsistent cross-sectional dimensions are tackled • The proposed method facilitates the quasi-regional clustering of geotechnical data [ABSTRACT FROM AUTHOR]

This paper proposes a new framework for discretizing the conditional random fields that combines the Hoffman method and Bayesian updating, where multiple types of geotechnical data can be utilized, such as the field monitoring data and the site investigation geological borehole data. The feasibility of the proposed method is demonstrated using a rainfall-induced slope example in spatially varying soils. Results showed that the proposed framework of incorporating Bayesian updating to Hoffman method can effectively reduce the uncertainty in site characterization and guarantee precise risk assessment of unsaturated slope stability. Otherwise, the slope failure probability and landslide sliding volume would be overestimated when only the Hoffman method is adopted for site characterization. Subsequently, the developed method is further used to estimate the probabilistic stability of Baishuihe landslide in the presence of rainfall infiltration and reservoir water level fluctuation. It is hoped that this study can provide a reference for risk assessment of the unsaturated slope stability in reservoir areas. • A novel conditional random field generation method is developed. • Site investigation and field monitoring data can be used for site characterization. • Effectiveness of the proposed method is verified via a rainfall-induced slope. • Baishuihe landslide is investigated under rainfall and reservoir water fluctuation. [ABSTRACT FROM AUTHOR]

The ink-bottle effect, resulting from the non-uniformity of pore structure, plays a significant role in the hydraulic behaviour of soils. In this paper, a series of laboratory tests including standard mercury intrusion porosimetry (MIP), intrusion-extrusion cyclic MIP (IEC-MIP), and scanning electron microscopy (SEM) were conducted on two soils (a Nanyang expansive clay and a Kaolin mixture) to examine the evolution pattern of ink-bottle effect in soils with different initial void ratios. To evaluate the impact of such evolution on the soil-water retention behaviour, the axis translation and vapour equilibrium techniques were utilised to measure the water retention curve of the tested soils (SWRC). A key part of the analysis involved a separation between pore bodies (or ink-bottle pores) and pore throats to facilitate a more thorough examination of the pore structure. The test results indicated that the reduction in soil volume during compression is mainly attributed to the reduction in pore body size, whereas the pore throat size remains relatively constant. Therefore, the ink-bottle effect would weaken with a decreasing initial void ratio, which will reduce the hysteresis potential of soils, manifesting as a contraction of the SWRC hysteresis loop. Additionally, under a fixed void ratio but with decreasing pore size, the ink-bottle effect will also weaken, which will reduce the distance between the drying and wetting curves with increasing matric suction. Finally, the mechanisms regarding how the evolution of ink-bottle effect during soil deformation influences water retention hysteresis were addressed. • Soil-water retention curves (SWRCs) of two soils under wetting-drying cycles were measured. • The ink-bottle effect was investigated using the intrusion-extrusion cyclic MIP test. • The weakening of the ink-bottle effect occurs as the initial void ratio of soils decreases. • Mechanisms for the contraction of SWRC hysteresis loop as the ink-bottle effect weakens are revealed. [ABSTRACT FROM AUTHOR]

The seismic stability assessment of anthropogenic cavities is a challenging issue for land and urban planning, particularly in areas of possible interaction with surface structures and infrastructures. The paper proposes a novel methodology for the preliminary assessment at urban scale of the safety level against roof collapse of underground cavities under seismic actions through seismic stability charts, SSCs. The SSCs are the result of extensive parametric two-dimensional FEM analyses focused on cavities excavated in soft rock, as it is frequent in many inhabited areas all over the world. The study is mainly oriented to the instability of shallow cavities, includingthe effects at the ground surface. The SSCs allow evaluation of stability conditions of a generic cavity through a factor of safety, calculated as the minimum ratio between the resistant and loading bending moment of the critical sections of the cavity roof during the whole earthquake duration. The method is applied to the case study of Sant'Agata de' Goti, a historical center in Southern Italy, rising on top of a volcanic tuff ridge. • Methodology to preliminary screen the seismic stability of underground cavities at urban scale. • Parametric 2D FEM analyses to calculate the cavity factor of safety during earthquake. • Analytical interpretation of cavity response under a seismic pseudo-static action. [ABSTRACT FROM AUTHOR]

Accurately predicting slope reliability under a rainfall/rainstorm event is an important prerequisite for preventing rainfall-induced landslide hazards. However, the predicted probability of slope failure under the rainfall/rainstorm event is often larger than the observed frequency of slope instability. The spatial variability of multiple soil parameters was rarely accounted for. To address this issue, this paper proposes an efficient sequential probabilistic back analyses approach for learning multiple spatially varying soil parameters using Bayesian Updating with Subset simulation (BUS) method. Two survival records of a real slope in India (i.e., the slope stays stable before the rainfall and the slope keeps stable after a 57-day weak rainfall) are successively used in the sequential probabilistic back analyses of soil parameters. The results indicate that the proposed sequential probabilistic back analyses approach can effectively update the distributions of multiple spatially variable soil parameters by the fusion of slope survival records. More accurate statistics of soil parameters can be obtained when additional slope survival records are used in the probabilistic back analyses. Furthermore, two slope failure records under a 3-day heavy rainfall event and a rainfall event ranging from May 1, 2016 to June 30, 2016 in Chibo, India are, respectively, used to predict the slope reliability and further validate the effectiveness of the proposed approach. The predicted probabilities of slope failure under the target rainfall events are well consistent with the actual observation frequency. The proposed approach can provide a powerful and versatile tool for determining the statistics of soil parameters and early warning of landslide hazards under the future rainfall events. • An efficient back analysis approach is proposed for learning multiple spatially variable soil parameters under rainfall. • The BUS method and surrogate models greatly facilitate the sequential probabilistic back analyses of soil parameters. • A real unsaturated slope is investigated to illustrate the effectiveness of the proposed approach. • The proposed approach can effectively update the distributions of soil parameters and slope reliability prediction. • The using of field observations can reduce the uncertainties of soil parameters and enhance the slope reliability prediction. [ABSTRACT FROM AUTHOR]