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Accurate determination of parameters for an advanced soil constitutive model highly relies on laboratory testing, even though it is notoriously difficult to obtain undisturbed samples for soft soils. This study explores the potential use of in situ tests, such as piezocone penetration tests (CPTU) and seismic dilatometer tests (SDMT), to estimate the constitutive model parameters. Based on a case history of a deep excavation adjacent to existing tunnels in silt/sand-dominated sediments, a calibration approach of a set of the HSSmall (Hardening Soil Model with small strain stiffness) model parameters is presented, and the derived parameters are used to numerically compute the interactive responses of tunnels and deep excavations. Several comparisons against field monitoring data indicate that the numerical model with the CPTU/SDMT-interpreted HSSmall model parameters adequately reproduces observed deformation responses of deep excavations adjacent to tunnels. However, in the considered case study, the use of laboratory tests with disturbed samples to estimate the stiffness parameters of the HSSmall model results in an overconservative solution. This finding supports the use of CPTU/SDMT to provide representative parameters for a range of soil layers, leading to the conclusion that tunnel linings may be beneficial to mitigate ground movements and wall deflections due to a "barrier" effect. [ABSTRACT FROM AUTHOR]

As a critical component in achieving the rock-breaking function during the operation of Tunnel Boring Machines (TBM), the cutterhead inevitably generates significant vibrations during the rock-breaking process. These vibrations can lead to localized damage to the cutterhead and cause the abnormal failure of key components, which, in turn, may compromise the overall tunneling efficiency of the machine. This study investigates the load and vibration characteristics of the cutterhead during the rock-breaking process, employing large-scale physical model experiments conducted at varying cutter spacings. Real-time acceleration data from the cutterhead can be obtained through the monitoring system integrated into the TBM (Tunnel Boring Machine) experimental platform. The whole time-domain curves are stepped and periodic, as demonstrated by the test results. During excavation, the monitoring curves vibrate suddenly if the cutter-head becomes stuck or if rocks begin to fracture. The cutter-head primarily exhibits vibrations in the 0∼3 Hz range, characteristic of low-frequency oscillations. To obtain the real-time mechanical properties of the cutter-head, transient dynamic analysis was employed, utilizing the collected data as driving parameters. According to numerical simulation results, the vibration pattern during excavation is the superposition of random vibrations generated by rock breaking and the unloading of the tunnel face. Moreover, it is important to monitor the wear of the edge cutters throughout the boring operation in real-world construction scenarios. To prevent and control cutterhead vibration, it is recommended that the cutter spacing be as small as possible during the tunneling process. At a smaller tool spacing, the cutterhead will exhibit higher structural integrity, which may lead to a delay in the response of mechanical vibration. The conclusions presented offer valuable insights for the study of the mechanical properties and stability design of TBM cutterheads. [ABSTRACT FROM AUTHOR]

Through analysing a significant number of case histories, ranges of applications of dewatering techniques for randomly fractured rock are proposed in terms of the rock mass permeability and the required drawdown. The cases analysed, which cover a wide range of construction activities and associated dewatering depths, provide one of the most comprehensive studies of dewatering techniques on randomly fractured rock to date. Comparison of the ranges suggested for dewatering in fractured rocks with those developed for excavations in soils is presented. To fit the construction dewatering systems in rock, a modification is proposed for the drawdown diagram that is widely used in practice for soils, and for the limited available general recommendations presented for chalk. Consequently, recommendations are made to improve the procedure of designing and executing these systems. In addition, a dewatering technique is proposed, which allows for construction to proceed in a wet condition, taking into account rock shear strength and the excavation geometry. [ABSTRACT FROM AUTHOR]

With the development of urban underground space, green and efficient excavation supporting structures are receiving increasing attention. Prefabricated recyclable supporting structures (PRSSs) have been developed for this reason. A deep circular excavation supported by PRSSs in low-plasticity clay (CL) was extensively instrumented to explore its deformation characteristics. Measurement results showed that the lateral displacement of the supporting piles (δhp) presented a typical cumulative pattern dominated by deep inward movement. The maximum lateral displacements of the supporting piles (δhpm) varied between 0.28%H–0.52%H (H is the excavation depth). The maximum lateral pile displacements mostly occurred above the excavation surface, ranging from H + 0.5 m to H − 7.0 m. The soils 3 m and 10 m from the excavation had the largest lateral displacement at the top and a cantilever shape. The ground surface settlements tended to follow a convex pattern. The maximum ground surface settlements (δvm) were normalised by the final excavation depth (He) on the east and south sides, and determined to be 0.43% and 0.50%, respectively. The ratio δvm/δhpm tended to increase as excavation and dewatering proceeded, with a value of 0.49–1.15. The ground surface settlement due to dewatering was 19% of the maximum settlement. [ABSTRACT FROM AUTHOR]

Earth pressure balance machine (EPBM) operation is sensitive to the properties of the excavated soil due to the requirements of proper soil conditioning and maintenance of necessary chamber pressure. However, soil properties are invariably only available at a limited number of borehole explorations and soil samplings conducted during the subsoil investigation. Thus, it is crucial to identify properties of the tunnel excavation face, such as clay-sand mixed conditions, grain size distributions, and clogging potential along the whole alignment beside the few borehole locations to attain optimally efficient EPBM operation. Therefore, this paper presents the development of machine learning prediction models (i.e., classifiers and regressors) to estimate the properties of the tunnel excavation face using EPBM operational data collected during the tunneling operation as input features. Geotechnical data collected from boreholes and soil samples can be used to validate prediction models and calibrate them. To develop such models, the Northgate Link Extension (N125) tunneling project, constructed in Seattle, Washington, the USA, is used to capture and identify the true ground conditions. The results indicate successful prediction performances by the models, providing indication that EPBM parameters are crucial pointers of the tunnel excavation face properties to help attain optimally efficient EPBM operation. [ABSTRACT FROM AUTHOR]

During the construction of deep and large foundation pits in floodplain areas, it is inevitable to cause stratum disturbance and endanger the safety of the surrounding environment. This paper focuses on the influence of deep foundation pit excavation on surrounding environment based on a soft soil deep foundation pit project in Nanjing floodplain area. A series of laboratory tests were conducted to obtain the parameters of the small strain hardening (HSS) model for the typical soil layers. Then PLAXIS 3D software is used to simulate the excavation process of the foundation pit. On the basis of field measurement and numerical model, the deformation characteristics of deep foundation pit and surrounding environment are analyzed. The HSS model and the appropriate model parameters can effectively simulate the deformation behavior during the excavation of the foundation pit. Aiming at the problem of excessive deformation of foundation pit and surrounding pipelines, the reinforcement effect of reinforced soil in active and passive areas under different reinforcement parameters is analyzed. The optimal reinforcement width and depth should be determined after reasonable analysis to obtain the best economic benefits. [ABSTRACT FROM AUTHOR]

Since the plasticity of soil and the irregular shape of the excavation, the efficiency and stability of the traditional local radial basis function (RBF) collocation method (LRBFCM) are inadequate for analyzing three-dimensional (3D) deformation of deep excavation. In this work, the technique known as the direct method, where the local influence nodes are collocated on a straight line, is introduced to optimize the LRBFCM. The direct method can improve the accuracy of the partial derivative, reduce the size effect caused by the large length-width ratio, and weaken the influence of the shape parameters on the LRBFCM. The mapping technique is adopted to transform the physical coordinates of a quadratic-type block to normalized coordinates, in which the deformation problem can easily be solved using the direct method. The stability of the LRBFCM is further modified by considering the irregular shape of 3D excavation, which is divided into several quadratic-type blocks. The soil's plasticity is described by the Drucker-Prager (D-P) model. The improved LRBFCM is integrated with the incremental method to analyze the plasticity. Five different examples, including strip excavations and circular excavations, are presented to validate the proposed approach's efficiency. [ABSTRACT FROM AUTHOR]

Research on the calculation method of deep-buried surrounding rock pressure is an important subject in engineering mathematics. The existing calculation methods are mainly the two-hole closely spaced tunnel, double-arch tunnel, three-hole closely spaced tunnel, and three-arch tunnel. The four-hole closely spaced double-arch tunnel has the characteristics of both the double-arch tunnel and closely spaced tunnel, and its surrounding rock pressure distribution is more complicated. In this paper, the research is carried out based on Protodyakonov's theory and the concept of process load. The influence of the post-construction tunnel on the supporting structure of the pre-construction tunnel is also considered. The calculation model of the surrounding rock pressure of the deep-buried four-hole closely spaced double-arch tunnel is established, and the calculation formula of the surrounding rock pressure is deduced and verified. Finally, the influences of the rock column parameters, excavation procedure, tunnel span, and middle partition wall on the surrounding rock pressure are analyzed. [ABSTRACT FROM AUTHOR]

Recently, there has been a growing interest in underground construction safety, during activities such as subway construction, underground mining, and tunnel excavation. While Internet of Things (IoT) sensors help to monitor these conditions, large-scale deployment is limited by high power needs and complex tunnel layouts, making real-time response a critical challenge. A delay-sensitive multi-sensor multi-base-station routing scheduling method is proposed for the IoT in underground mining. First, a mixed network topology of wireless and wired networks is formed based on the irregular distribution characteristics of multiple tunnels in the mine construction environment. Based on this topology, a multi-sensor and multi-base-station real-time routing scheduling problem is proposed, proving that the problem is NP-hard. Secondly, the corresponding solving algorithms are designed based on the greedy strategy and the heuristic strategy. Finally, an experimental platform is built, and the performance of the proposed algorithm is compared and analyzed. [ABSTRACT FROM AUTHOR]

Aiming at the crucial engineering challenge of the ambiguous excavation deformation mechanism of hard and brittle surrounding rock under high geos-tress conditions, with the right bank diversion tunnel at the dam site of the hydropower station as the research object, the deformation and failure characteristics of the surrounding rock and their formation mechanisms during the layered excavation of the diversion tunnel were investigated. The research findings show: (1) The main factors influencing the deformation of the diversion tunnel's surrounding rock are the high ground stress environment, the degree of fracture development in the rock mass, and the effectiveness of the support system. (2) Following the excavation of the first layer, extensive shallow damage predominates, with damaged blocks primarily exhibiting sheet-like and plate-like forms. After excavating the second and third layers, there is a significant reduction in confining pressure in this region, leading to a rapid deterioration in the extent of damage. (3) Layered excavation induces 'time-dependent' variations in the yield characteristics of the surrounding rock, while simultaneously being influenced by the location and extent of fracture development. The study results are expected to provide a theoretical basis for the excavation of underground caverns under high ground stress. [ABSTRACT FROM AUTHOR]

The excavation of the super-large cross-section tunnel portal section is prone to causing serious engineering distresses. The key factors to ensure the safe construction of portal section are to clarify the construction mechanic characteristics and select a reasonable construction scheme. In this paper, a bidirectional six-lane expressway tunnel in Southwest China was selected as an engineering case. Three excavation schemes, namely, the three-bench seven-step excavation method (TEM), the central diaphragm method (CDM), and the double side drift method (DSDM), were compared and analyzed. Findings revealed that due to the effect of the asymmetrically loaded and super-large cross-section, the surrounding rock deformation and supporting structure stress at the deep buried side were greater than those at the shallow buried side. The CDM and DSDM could reduce the tunnel span and provide temporary support in time, which could effectively control the surrounding rock deformation and improve the structural stress and the slope stability. According to the topographic condition, the excavation sequence of the DSDM was optimized. Excavating the shallow buried side drift first could alleviate the surrounding rock deformation and improve the slope stability in the early stage of construction. Finally, the optimal excavation scheme was successfully implemented. [ABSTRACT FROM AUTHOR]

Mine rock dynamics is a critical and challenging issue in ensuring mine safety, with significant engineering applications. In practice, the study of dynamic problems in mining environments, such as blast vibrations, mechanical excavation disturbances, and deep" three-high and one-disturbance" conditions, is crucial for safe production and disaster prevention in mines. This paper analyzes recent issues related to mine rock dynamics disasters and reviews progress in the field from 3 perspectives: the theoretical development and preliminary achievements of mine rock dynamics, research methods, and investigative tools. Key scientific challenges in the development of mine rock dynamics are identified, and future development trends are outlined. [ABSTRACT FROM AUTHOR]

Buckling failure is one of the common failure modes of rock mass after the excavation and unloading of deep-buried tunnels, which brings major safety risks to the construction of deep engineering. According to the force characteristics of slabbing rock mass, it is simplified to the bending failure of rock plate under multi-directional constraints. Multi-directional constraints buckling failure tests of single-layer plates (thickness 10 mm, 20 mm) and laminated plates were carried out, and the influence of plate thickness and interlayer contact pressure on buckling failure were analyzed. The results show that the bending stiffness and ultimate bearing capacity of the rock plate are affected by the thickness of the single-layer plates and the interlayer friction of the laminated rock plates. When the lateral pressure is small, with the increase of the lateral pressure, the plasticity of the three types of rock plates increases first and then weakens. The failure mode of the single-layer rock plates gradually changes from X-shaped failure to spalling failure, while the laminated rock plate is mainly X-shaped failure. The X-shaped cracks and spalling shape of the plates are controlled by the ratio of lateral pressure. When the lateral pressure and constraints of the upper and lower plates of the laminated rock plate are consistent, the deformation of the two plates is compatible. When the lateral pressure and constraints of the two plates are inconsistent, the two plates may be delaminated. Through numerical simulation, it can be seen that with the increase of the bending degree of the plate, the force mode of the laminated plate gradually changes from point load to circle load, and the contact pressure area between the layers also changes. Highlights: Buckling failure in deep-buried tunnels is simplified to the bending of thin plate under multi-directional constraints. Strength, deformation, and failure characteristics of single-layer and laminated plates are analyzed. Mechanism of strong–weak plasticity transformation of rock plates is explained. Evolutions of the rock plates buckling failure are analyzed by endoscope. Bending characteristics of the laminated rock plates under different constraints are obtained. [ABSTRACT FROM AUTHOR]

Background: Urban trees are commonly impacted by construction activities. Often, damage occurs below ground, as trenching, grading, and excavation activities disrupt tree root systems. Methods: In this study, 30 Acer rubrum L. were intentionally damaged by simulated trenching treatments. Treatments were randomly assigned at 1× (n = 10), 3× (n = 10), or 5× (n = 10) stem diameter away from the base of the tree. Root systems and severed roots were excavated, cleaned, and digitized using photogrammetry to assess losses in root volume. This measure, as well as changes in bending stress, were compared among the 3 treatments. Results: The 1× and 3× treatments exhibited the highest bending stress loss (%), correlating with the highest observed root loss. A positive relationship was noted between root volume loss and bending stress reduction (r2 = 0.5466). Conclusions: These results support previous studies that utilized similar trenching treatments on different tree species. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Architecture & Civil Engineering is the property of Chang'an Daxue Zazhishe and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Architecture & Civil Engineering is the property of Chang'an Daxue Zazhishe and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Pearl River is the property of Pearl River Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Taking the foundation pit of the Suzhou Chunshenhu Road Expressway Reconstruction Project as an example, the excavation process of the foundation pit was numerically simulated using a three-dimensional finite element method. The measured data and simulated data of the lateral deformation of the enclosure structure, surface settlement deformation of the ground outside the pit, and settlement deformation of the building were compared to analyze the impact of foundation pit construction on adjacent buildings. The influence of foundation pit floor and diaphragm wall thickness on wall displacement, building settlement, and foundation pit uplift was also discussed. The results showed the following: (1) Adding a foundation pit floor has a significant effect on reducing the lateral displacement of the diaphragm wall, settlement of the building, and uplift of the foundation pit. Increasing the thickness of the foundation pit floor has a limited effect on reducing the displacement, while increasing the thickness of the diaphragm wall has a small effect. (2) The displacement curve of the underground diaphragm wall increases with depth. It reaches a maximum at the excavation surface and then decreases gradually. (3) The surface settlement increases first and then decreases with distance from the foundation pit, showing a concave shape. As the depth of excavation increases, the settlement value increases. (4) Through analysis of the monitoring data of vertical displacement of buildings, it can be seen that during foundation pit excavation, buildings undergo five stages: initial slow descent, steep descent, mid-term slow descent, late steep descent, and stable deformation. The buildings are dominated by settlement deformation. [ABSTRACT FROM AUTHOR]

In soft soil foundations, the utilization of box-type retaining walls as a support method represents a novel approach. This study focuses on investigating the key factors influencing lateral wall deflection and ground settlement behind the wall in deep excavation projects supported by box-type retaining walls. Based on a practical engineering case in Shanghai, the large deformation Lagrangian numerical simulation software FLAC-3D is employed to simulate the displacement of box-type retaining walls as well as the surface settlement surrounding the excavation pit during the excavation process of deep-foundation pits. This research encompasses aspects such as the box size, the filling material within the box, and the constituent materials of the retaining wall. Ultimately, it is concluded that variations in the size of the box-retaining wall have a significant impact on wall deflection and surrounding ground settlement, while the filling material and constituent materials have relatively minor effects. This study provides a theoretical basis and scientific reference for the design and construction of box-type retaining walls in deep-foundation pit engineering. [ABSTRACT FROM AUTHOR]

With the further development of China's coal resources, mining operations are constantly transferred to the deep soft rock. As such, the mine roadway is under the action of high geostress, the surrounding rock body engineering properties are poor, the overall strength is low, the traditional support method struggles to meet the needs of safe production, and the surrounding rock control has become a major technical challenge. This paper relies on the actual project, analyzes the destabilization mechanism of the roadway, analyzes the deformation of the peripheral rock of the deep roadway, determines the physical and mechanical parameters of the peripheral rock through indoor tests, establishes numerical analysis model, proposes to adopt the joint support scheme of anchor rods + anchor cables + a 36U-type steel metal bracket + a laying net + a laying mat + filling behind the wall, and monitors the displacement of peripheral rock of the roadway on a regular basis by using the numerical display convergence meter, and then obtains the displacement of the peripheral rock of the roadway after excavation as well as under the influence of the quarrying movement. Under the influence of the roadway perimeter rock displacement, we evaluate the reasonableness of the support program, as well as the safe and effective control of the roadway perimeter rock, to achieve the ideal roadway perimeter rock support and control effect. [ABSTRACT FROM AUTHOR]

This study provides a theoretical foundation for optimizing tunnel boring machine (TBM) excavation parameters under diverse geological conditions, offering significant engineering value by enhancing construction efficiency and reducing costs. As the development of underground spaces advances, TBMs play a pivotal role in tunnel excavation. TBMs enhance safety in excavation by mechanically breaking rock, reducing the reliance on explosives, and the associated risks of blasts. The shield support minimizes surrounding rock collapse, advanced geological forecasting mitigates risks posed by complex geologies, and intelligent monitoring systems improve operational safety. To enhance TBM efficiency and safety, this study developed a 3D simulation model of rock breaking by disc cutters using the discrete element method. This study systematically examined the effects of excavation parameters, including disc-cutter diameter, cutter spacing, and penetration, on rock-breaking performance. The findings reveal, that as the disc-cutter diameter increases, the rolling force also increases, while the rock-breaking specific energy initially rises and then declines. The 19-inch disc cutter demonstrated a superior rock-breaking efficiency in conventional excavation operations. At a cutter spacing of 60 mm, the rock-breaking specific energy reached its lowest value, representing optimal efficiency. Furthermore, as the penetration increased, both the rolling force and rock fragmentation volume grew, whereas the specific energy decreased, further improving the rock-breaking efficiency. [ABSTRACT FROM AUTHOR]

Copyright of Railway Construction Technology is the property of Railway Construction Technology Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Railway Construction Technology is the property of Railway Construction Technology Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Railway Construction Technology is the property of Railway Construction Technology Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Railway Construction Technology is the property of Railway Construction Technology Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Railway Construction Technology is the property of Railway Construction Technology Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

A trajectory tracking control scheme is proposed in this paper to achieve unmanned underground construction of a new type of shaft boring machine. The body motion model is constructed, and the control relationship between the driving system and the body motion is deduced. MATLAB and Simulink simulate the joint of the track tracking process in the new shaft boring machine. The actual effect of the track tracking control scheme is validated by the track tracking field test of the new shaft boring machine. The results show that the new shaft boring machine can complete various complex track tracking tasks, with the maximum position error being less than 0.005 m. The running track and excavation areas of the boring machine are observed along with the track tracking field test of the new shaft boring machine, demonstrating that the track tracking control scheme makes the new shaft boring machine realize unmanned construction and verifies the co-simulation accuracy. The PID (proportional–integral–derivative control) algorithm can complete complex trajectory tracking tasks and promote the development of unmanned construction technology. [ABSTRACT FROM AUTHOR]

Taking the conducted model test by authors as the research object, this paper first carries out detailed numerical analysis and verifies the reliability of the established model. Furthermore, the test phenomenon is explained based on numerical analysis, while parameter analysis is carried out, which mainly includes soil deformation between piles and soil deformation inside and outside excavation. The research results show that when the inclination angle of the piles is small (such as 10°), all or most of the soil (the range of the pile top to 0.6L) between the piles is compressed in the horizontal direction, and the piles and the soil between the piles can be regarded as a whole. When the inclination angle of the piles is large (such as 20°), all or most of the soil (the range of the pile top to 0.6L) between piles is in a relaxed state in the horizontal direction, and the piles deform independently. The research results also show that the maximum displacement of the soil on the surface outside the excavation occurs around the retaining pile, and the displacement distribution patterns change with different types of retaining structures and inclination angle. [ABSTRACT FROM AUTHOR]

Vibration caused by shield tunneling construction have adverse impacts on surrounding environment. To ascertain the influence of shield tunneling construction on ambient vibration, based on the shield tunnel project of Zhijiang Road in Hangzhou, the on-site vibration tests were carried out on the deep soil and surface during the excavation, and the vibration characteristics and vibration attenuation law during shield construction were investigated. The results show that the main frequency of vibration near the vibration source is wide, and the response components can be observed at 0–100 Hz. Under the filtering effect of the surface-covering soil layer, the high-frequency components of the vibration response are significantly attenuated, and the surface vibration is mainly distributed within 40 Hz. In the shield crossing, the deep measurement point is 5 dB higher than the vibration level of the same position on the surface. After the shield is pushed forward 20 m, the average attenuation of the surface vibration response is 10 dB, and the average attenuation of the deep vibration response is 12 dB. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Henan University of Science & Technology, Natural Science is the property of Editorial Office of Journal of Henan University of Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Ground subsidence is one of geohazards, particularly in urban environment due to its negative impact to nearby buildings and civil infrastructures. This study investigates the amount and spatial distribution of ground subsidence in Incheon City, South Korea, where ground excavation was made. Interferometric Synthetic Aperture Radar (InSAR) was used to monitor surface deformation around the excavation site. The study analyzed subsidence during an excavation project using Sentinel-1b satellite data, and the InSAR results were compared with traditional leveling methods and field measurements. Notable subsidence during the early construction phase was identified, which demonstrates the effectiveness of InSAR in urban environment. The research contributes to understanding of the excavation-inducing ground subsidence due to the reclamation layer. [ABSTRACT FROM AUTHOR]

The advancement of urbanization has led to stricter requirements for the prediction and control of excavation-induced deformations. To achieve this goal, this study proposes a novel method that integrates a spatiotemporal graph attention network (ST-GAT) with a proportional–integral–derivative (PID) controller to proactively control wall deflections caused by excavation. The ST-GAT model improves wall deflection prediction by capturing spatial relationships between monitoring points near steel struts and dynamically assigning weights based on their importance. The interpretability of the model is greatly improved by generating a feature attribution map across various input features and visualizing the weight distribution between nodes in the GAT network. A proactive control method of wall deflections is proposed by replacing current monitoring values in the PID control system with predicted values for multiple steel struts using the ST-GAT model. Compared to the standard PID method, this approach can control wall deflections before significant deformations occur. A real excavation project equipped with a servo support system is used to validate the effectiveness of the proposed method. The results show that the ST-GAT model significantly outperforms other models, and its performance improves when utilizing spatial relationships from more monitoring points. With a reasonable combination of PID hyperparameters, the proposed ST-GAT-based PID controller can control wall deflections close to a target value. [ABSTRACT FROM AUTHOR]

When excavating tunnels in urban areas with shallow overburden in poor rock mass, the deformations are very pronounced, which can result in serious potential risks to the safety, costs and time of tunnel construction. In the Kobilja Glava tunnel, which will be part of the project connecting Vogošća with Sarajevo and connecting the city center of Sarajevo with the A1 motorway on Corridor Vc, monitoring of displacements was conducted in a specific section of the left tunnel tube over a length of 80 m, in terms of various distances between the top heading excavation and the primary invert in poorer rock mass with a defined RMR ranging from 27 to 32. The results indicate that displacements can be effectively controlled by defining the optimal distance between the excavation phases of the top heading and the primary invert. A detailed analysis of the collected data yielded a mathematical function relating displacement to the distance between the excavation of the top heading and the primary invert, which can serve as a tool for quick and straightforward correlation of displacements during tunnel excavation, considering the geological conditions present in the Kobilja Glava tunnel. [ABSTRACT FROM AUTHOR]

The "yield-resist" combined support measure is a widely employed control measure in soft rock tunnels for controlling large deformation, particularly in high geostress conditions. For strain-softening rock masses, the strength parameters in the plastic zone are coupled with the support reaction. Due to the complexity of the interaction mechanism between yielding support and strain-softening surrounding rock, the majority of current solutions are based on the plane–strain model. However, the advancement of the tunnel is a three-dimensional problem. Therefore, the longitudinal effect is worthy of discussion when analyzing the mechanical behaviors of strain-softening rock and yielding support. A new two-stage method is proposed to describe the interaction between strain-softening rock mass and yielding support based on the generalized Zhang–Zhu (GZZ) strength criterion. Firstly, a simplified mechanical model of the yielding support structure is suggested to describe the mechanical response of the surrounding rock and support. Subsequently, a semi-analytical solution to three-dimensional ground–support interaction is proposed, taking into account the longitudinal effect. The results of the proposed solution are compared with those of a finite element simulation, and a high degree of agreement is observed. Finally, the mechanical behaviors of different yielding supports are discussed. The findings indicate that postponing the support timing by means of yielding technologies is essential, as otherwise the support would bear a very large load. The second stage of support reaction can be significantly reduced by implementing the "control-yield-resist" (CYR) support. The research offers novel insights and methodologies for investigating the three-dimensional interaction between the surrounding rock and various tunnel supports in high geostress conditions. [ABSTRACT FROM AUTHOR]

This study presents an improved in-flight strutting system for centrifuge modelling. Based on the centrifuge model test data, the mobilizable strength design (MSD) method was revised. The modified MSD method extends to the prediction of three-dimensional (3D) deformations in retaining walls due to excavation activities. Initially, an improved in-flight excavation tool used in centrifuge tests was employed to investigate the impacts of staged excavation on the characteristics of wall displacement and ground settlement in two-dimensional (2D) braced excavation. Subsequently, 2D and 3D finite element analyses, calibrated against the centrifuge test data and considering the small strain effect, were conducted to assess the performance of wall displacement, ground settlement, and movement of the underground soil induced by the braced excavation. Moreover, this research proposes a straightforward predictive model based on the modified MSD, specifically for calculating the deformation along the length of retaining walls in 3D braced excavations. The insights and the modified MSD method given in this study may facilitate the design of foundation pit projects, especially when the 3D effects are an essential detail to be considered in these projects. [ABSTRACT FROM AUTHOR]

In view of the face stability of a shallow-buried shield tunnel excavation, this paper investigates the problem using an adaptive finite-element limit analysis combined with slip-line theory. First, a series of adaptive finite-element limit analyses are conducted to explore the passive failure mechanisms of the shallow-buried shield tunnel face. Based on the characteristics of the failure mechanisms, a funnel-shaped asymmetric boundary failure mechanism is proposed. Then, a mathematical computational model is established using the slip-line method, which considers the characteristics of the passive failure mechanisms and the stress state of the plastic region in the surrounding soil. The formula for calculating the limit support pressure for the passive failure of the shield tunnel face is derived using the finite-difference method, and the passive failure mechanisms of the face are analyzed. Finally, the calculated results of the model are compared with existing research results and the numerical results in this paper. The results show that the proposed computational model could accurately analyze the face stability of shallow-buried shield tunnels and might have wide applicability in the analysis of the limit support pressure and failure mechanisms of the face in shallow-buried tunnels. [ABSTRACT FROM AUTHOR]

The support pressure at a shield tunnel face is significant for the stability of the shield excavation and prediction of ground disturbance. This study presents an optimization measure that relies on the three-dimensional (3D) limit equilibrium method (LEM) to determine the reasonable support pressure of the shield tunnel face. The predetermined support pressure is subsequently incorporated into the finite-element (FE) model, and the ground disturbance that is induced by the shield excavation could be estimated by the FE simulation. The face support pressure that is obtained from the optimization measure aligns remarkably well with those derived from other methodologies, therefore confirming its efficacy. Furthermore, the numerical results demonstrate that the support pressure, as determined by the optimization measure, provides superior control on the ground disturbance. To further estimate the sensitivity of the tunnel buried depth and soil strength in relation to the ground disturbance, orthogonal testing is conducted. The outcomes of this orthogonal testing inform the development of a predictive approach for evaluating ground disturbances that are caused by the shield excavation, which is then validated by comparing it with previous works. The findings of this study serve as a valuable asset in facilitating the rapid prediction of ground disturbance that is induced by shield excavation. [ABSTRACT FROM AUTHOR]

During tunnel construction, the excavation face frequently encounters heterogenous weathered composite strata that considerably reduce tunnel face stability. To assess the stability of the tunnel face under such conditions, a 3D analysis model is established using the limit analysis approach. The model comprehensively assesses the failure of the entire tunnel face, incorporating the Hoek-Brown criterion to account for the nonlinear failure characteristics of rock. In addition, improvements are made to the shape of the sliding surface in the cover layer to consider the influence of the arching effect. The proposed model is validated by comparisons with existing theoretical methods and numerical simulation results. Further parameter analysis is conducted to investigate the influence of stratum parameters, stratum thickness and tunnel depth. The results indicate that tunnel face instability is more likely to occur when the rock mass quality of the higher layer is greater than that of the bottom layer. The rock mass in the bottom layer has the most remarkable impact on the tunnel face stability compared with the cover layer and higher layer. The stability of the tunnel face initially decreases and then increases with the tunnel depth due to the rock-arching effect. These research results can provide useful references for tunnel face support design in composite strata. [ABSTRACT FROM AUTHOR]

As coal mining depths increase, rockbursts pose a significant threat to the safety of coal mine operations. Addressing the challenge of safely and steadily advancing excavation faces amid rockburst hazards, this study assesses the current state of reinforcement support technology for rockburst-prone roadways. It scrutinizes the concept of roadway anti-rockburst hydraulic support, support design, and the integration with the surrounding rock mass. The research delineates key directions for enhancing support systems, including the mechanical mechanisms of anti-rockburst hydraulic support, integrated roadway and support design, the synergistic pressure-equalizing effect of primary supports and bolts(cables), and the development of robotic systems for roadway anti-rockburst hydraulic support reinforcement. We propose an integrated design approach that holistically addresses both primary and reinforcement support in rockburst-prone roadways. To tackle the challenge of handling hydraulic supports in confined spaces, we developed a gantry hydraulic support system capable of self-movement with mechanical arm assistance for anti-rockburst hydraulic support. Field trials demonstrate that this system enables cyclical support advancement and retraction, automating and intelligently managing the underground advanced support sector. This innovation significantly reduces worker numbers and labor intensity, enhancing operational safety and efficiency. Furthermore, the system facilitates permanent support via bolt drilling under hydraulic protection, effectively mitigating the risks associated with unstable temporary roadway support and unsafe working conditions without proper roof coverage, thereby ensuring the secure and efficient operation of mining face. [ABSTRACT FROM AUTHOR]

The development of transportation in large cities requires the construction of new structures subterranean in close proximity to existed structures subterranean. Finding the best appropriate position of the new structure subterranean will help to minimize the magnitude of movement there will be in soil surrounding the existing one. The purpose of this study is to involve assessing the immediate influences that will result from the new tunnel excavation in close proximity to existed tunnel at different angular positions ß (0° to 180°) relative to existing one, especially destabilization of the soil surrounding, including movements, displacements of soil mass and surface settlement, in addition to internal efforts generated in lining of old tunnel, and to provide a solution by selecting an ideal angular position for the tunnel that will be excavated relative to the existing one. This is a crucial factor when searching for a full solution to the problem of interactions between subterranean structures. This study uses numerical analysis to examine the movements and displacements of soil mass surrounding, the settlement and the internal efforts induced in the old tunnel's lining impacted by the new tunnel excavation. Several factors, such as the excavation technique, tunnel spacing, liner thickness, etc., had a favorable impact on diminishing the extreme values acquired at the critical angle position (ß =135°). A parametric study was conducted to minimize the maximum values obtained. As a result, these elements could affect planning and security objectives. [ABSTRACT FROM AUTHOR]

This study introduces the Passive Earth Reinforcement for Lateral Equilibrium Optimisation (PERLEO) methodology, a novel approach to enhancing stability in deep excavations. Aimed at addressing limitations in existing geotechnical practices, especially in reducing deformations and bending moments in retaining structures, PERLEO utilises soil–cement blocks as passive reinforcement. Employing comprehensive numerical analysis through PLAXIS 2D software, the research advances traditional methods with sophisticated computational modelling. This study thoroughly evaluates the effect of soil–cement blocks' geometrical configurations on the lateral displacement and bending moments of retaining walls. Key findings indicate that optimal dimensions of these blocks significantly mitigate wall deflection and bending moments, thereby enhancing the stability and the overall integrity of deep excavation projects. Additionally, this research introduces design charts, providing tools for engineers to determine the estimates for maximum lateral displacement and maximum bending moment, based on the specific dimensions of soil–cement block configurations and the depths of excavation and embedment. This methodology not only contributes to improved safety and efficiency in deep excavation works but also offers a more economical approach by reducing potential financial and temporal hazards associated with structural failures in complex geotechnical projects. [ABSTRACT FROM AUTHOR]

In this study, aiming at the practical application of additional layer excavation technology in the renewal and reconstruction of old urban communities, the influence of different excavation methods on the settlement behavior of existing structures is deeply analyzed through numerical simulation experiments. It is found that the frame columns show basin-type settlement in the block layered excavation, basin excavation and central island excavation. The cumulative settlement of the middle column is the largest, and the corner column is the smallest. The settlement phenomenon is mainly concentrated around the frame columns Z6, Z7, Z10 and Z11, and the change law of the cumulative settlement value conforms to the linear function distribution. By defining the cumulative settlement rate (a) as an index to measure the influence degree of the existing structure, it is found that the a value of the middle column is the largest, the side column is the second and the corner column is the smallest, and the a value of block layered excavation is the largest, and the central island excavation is the smallest. Considering the construction period, block layered excavation may be a more appropriate choice. The comparative analysis of the research results and the model experiment results confirms the feasibility of the improved model experiment, provides an important theoretical basis and practical guidance for the renewal and transformation of old urban communities and is of great significance for improving the utilization efficiency and safety of existing buildings. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Social Sciences Research / Sosyal Bilimler Arastirmalari Dergisi is the property of ODU Journal of Social Sciences Research and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Selçuk University Journal of Faculty of Letters is the property of Selcuk Universitesi Edebiyat Fakultesi Dergisi and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The double‐row capsule grouting (DRCG) is an innovative technique which can restrain the horizontal and vertical tunnel deformations induced by excavation simultaneously. The real‐time and active control capacity of DRCG can overcome the shortcomings in invariance and inefficiency of the traditional protective approaches. However, the performance of DRCG and the prediction method of control effectiveness have not been investigated. A numerical analysis using the hardening soil model with small‐strain stiffness (HSS model) is conducted to investigate the influences of the relative buried depth and the grouting volume of capsule on the control effect of DRCG in relation to the restoration ratio of horizontal deformation (Rh), and restoration ratio of vertical deformation (Rv). A polynomial relationship between parameters and restoration ratio is observed. Furthermore, a dimensionless formula, developed from hypothetical cases, shows a high conformity between predicted and numerical results. It can accurately predict the control effectiveness of DRCG. [ABSTRACT FROM AUTHOR]

This study introduces a local radial basis function collocation method (LRBFCM) to analyzing structural deformation in deep excavation within a two dimensional geotechnical model. To mitigate the size effect caused by a large length-to-width ratio, a technique known as the 'direct method' is employed. This method effectively reduces the influence of the shape parameter, thereby improving the accuracy of the partial derivative calculations in LRBFCM. The combination of LRBFCM with the direct method is applied to the deep excavation problem, which consists of both the soil and support structures. The soil is modeled using the Drucker-Prager (D-P) elastic-plastic model, while an elastic model is employed for the support structure. Elastic-plastic discretization is performed using incremental theory. The proposed approach is validated through four different examples, comparing the results with numerical solutions obtained from traditional finite element methods (FEM). This study advocates the use of the direct method to optimize the distribution of local influence nodes, particularly in cases involving large length-to-width ratios. The combination of LRBFCM with incremental theory is shown to be effective for addressing elastic-plastic problems. [ABSTRACT FROM AUTHOR]

A scientific and reasonable microseismic monitoring sensor network is crucial for the prevention and control of rockmass instability disasters. In this study, three feasible sensor network layout schemes for the microseismic monitoring of Sanshandao Gold Mine were proposed, comprehensively considering factors such as orebody orientation, tunnel and stope distributions, blasting excavation areas, construction difficulty, and maintenance costs. To evaluate and validate the monitoring effectiveness of the sensor networks, three layers of seismic sources were randomly generated within the network. Four levels of random errors were added to the calculated arrival time data, and the classical Geiger localization algorithm was used for locating validation. The distribution of localization errors within the monitoring area was analyzed. The results indicate that when the arrival time data are accurate or the error is between 0% and 2%, scheme 3 is considered the most suitable layout; when the error of the arrival time data is between 2% and 10%, scheme 2 is considered the optimal layout. These research results can provide important theoretical and technical guidance for the reasonable design of microseismic monitoring systems in similar mines or projects. [ABSTRACT FROM AUTHOR]

ABSTRACT Two‐dimensional analysis of tunnel design based on the convergence–confinement method, although commonly used in tunnel design, may not always be applied. For example, in squeezing grounds, if the support is installed very close to the tunnel face, three‐dimensional numerical modeling is required but is computationally expensive. Therefore, it is usually performed before or after tunnel excavation. A machine learning approach is presented here as an alternative to costly computations. Two surrogate models are developed based on synthetic data. The first model aims to assess the support pressure and the radial displacement at equilibrium in the lining and the radial displacement occurring close to the face at the installation distance of the support. The second model is intended to compute the extrusion of the core considering an unlined gallery. It is assumed a circular tunnel excavated in a Mohr–Coulomb elastoplastic perfectly plastic ground under an initial isotropic stress state. In particular, the bagging method is applied to neural networks to enhance the generalization capability of the models. A good performance is obtained using relatively scarce datasets. The modeling of the surrogate models is explained from the creation of the synthetic datasets to the evaluation of their performance. Their limitations are discussed. In practice, these two machine learning tools should be helpful in the field during the excavation phase. [ABSTRACT FROM AUTHOR]