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30 June 2026, Volume 40 Issue 3 Previous Issue   

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Key Methods for Risk Control of the Underground Excavation of a Large-Span Subway Transfer Gallery in Complex Environments NIE Ziyun, TAN Xiaobing, ZHU Zhanguo, FENG Gaofei, WANG Zhengsong, SHI Dan 2026, 40 (3):  387-392.  Abstract ( 98 )   Save Taiyuan Street Station on Shenyang Metro Line No. 4 is located in a dense commercial district. The station’s transfer gallery spans more than 10 m, with a minimum soil cover of only 4.5 m. The construction area is tightly surrounded by surface buildings, underground shopping streets, existing metro stations, regional rail lines, and multiple entrances and exits. This paper examines the challenges posed by such a large-span underground excavation and proposes targeted engineering measures. It focuses on key techniques for environmental risk control, right-angle turning excavation, and large-scale openings in existing side walls. Measures such as soil reinforcement and isolation pile installation are implemented to minimize the impact of excavation on the sensitive surroundings. A lateral docking scheme is adopted to reduce the risks typically associated with right-angle steering in large-span underground works. Segmental ring-beam casting is used to enhance the safety of opening existing side walls. Numerical simulations and monitoring data confirm the effectiveness of these technical strategies. The experience gained provides valuable reference for similar future projects. Related Articles | Metrics

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Impact of Deep Excavation in Soft Soil Areas on Adjacent Existing Subway Tunnels SHI Guanyu, QIN Xingfeng 2026, 40 (3):  393-397.  Abstract ( 66 )   Save Excavation-induced unloading in deep foundation pits can generate undesirble deformation in adjacent operational tunnels, posing risks to structural integrity and service performance. This study documents a commercial complex project constructed in close proximity to an existing subway tunnel. A three-dimensional coupled excavation-tunnel model was developed using finite-element analysis, incorporating the small-strain soil behavior of soft ground and simulating the staged excavation process. The model was used to quantify the evolution of tunnel crown deformation throughout construction. Complementary field monitoring captured horizontal tunnel displacement and the response of adjacent soldier piles. Results indicate that installation of a water-stop curtain effectively stabilized the hydraulic regime, with negligible variation in total head beneath the existing tunnel. Excavation activities produced substantially greater impacts on horizontal displacement, ground settlement, and tunnel deformation than subsequent backfilling or superimposed surface loads. The most significant effects were confined to the excavation influence zone, with maximum deformation occurring near the excavation centerline. Upon completion, measured soldierpile deflections and tunnel deformations remained within allowable limits, demonstrating that the adopted support system provided effective control of excavation-induced tunnel movements. Related Articles | Metrics

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Optimized Design of a Rigid-Flexible Combined Diaphragm Wall in a Super-Deep Excavation ZHOU Chong, YAN Changhong, LI Hui, XU Yuan, YU Liangchen, QI Lei, ZHANG Wenlong, XU Chenghua, LIU Gang 2026, 40 (3):  398-403.  Abstract ( 66 )   Save A rigid-flexible composite diaphragm wall system has been newly implemented in an ultra-deep excavation within the Yangtze River floodplain. In this system, the upper rigid diaphragm wall primarily controls lateral deformation, while the lower flexible section enhances seepage resistance by lengthening the groundwater bypass path, offering a cost-effective design strategy. This paper presents the engineering application of this system in a super-deep, large-scale excavation for a Nanjing metro station. Numerical analyses using PLAXIS 3D are conducted to investigate the support mechanism and optimize design parameters. Results indicate that, for a 70 m deep diaphragm wall, structural contribution below approximately 45 m is limited, allowing the use of lean concrete in the lower portion. The short-side diaphragm wall can safely extend to twice the excavation depth. For irregular wall geometries, the upper rigid section governs deformation control, whereas irregular long walls require increased rigid-section depth to satisfy safety criteria. Based on these findings, selected rigid walls were redesigned as rigid-flexible composite walls, achieving both deformation and seepage control while significantly reducing construction costs. The study provides valuable reference for similar ultra-deep excavation projects. Related Articles | Metrics

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Deformation Control Measures for Open Cut Tunnels Under a High Unloading Ratio Operation WANG Jinlong, SUN Xuebing, SONG Jianyu , WANG Bo, ZHANG Liren 2026, 40 (3):  404-409.  Abstract ( 61 )   Save The underground community-corridor project at Xiamen North Railway Station is situated directly above an operational open-cut tunnel of Xiamen Metro Line 1, with approximately 231 m of parallel overlap and a vertical clear distance of only about 3 m. The corridor excavation reaches a width of 64.5 m, producing a vertical unloading ratio of roughly 70%. To ensure deformation stability and operational safety of the underlying tunnel, it is essential to investigate the tunnel deformation patterns and corresponding control measures during excavation. A numerical simulation is conducted to analyze the deformation behavior of the operational open-cut tunnel under large unloading conditions. Two deformation-mitigation strategies are proposed: an inverted L-shaped anti-floating system and staged excavation with skipping compartments. Their effectiveness is verified through three-dimensional finite-element analysis and field monitoring. The inverted L-shaped anti-floating system—comprising a top-pressing pier, existing subway retaining piles, newly installed uplift piles, and longitudinal beams atop the uplift piles—effectively mitigates rebound deformation of the operational tunnel under ultra-long, close-proximity parallel conditions. During construction, staged excavation with skipping compartments leverages spatial effects to rapidly reconstruct the corridor’s main structure, generating counter-pressure on the underlying tunnel and significantly reducing vertical deformation. Results from numerical simulations and field monitoring confirm that combining the inverted L-shaped anti-floating system with staged excavation and compartment skipping successfully controls tunnel uplift within safe limits, ensuring structural stability and maintaining normal metro operations. Related Articles | Metrics

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Construction of Bored Cast-In-Place Concrete Piles in Deep Fill Strata for Lanzhou Metro MA Fengxue 2026, 40 (3):  410-414.  Abstract ( 48 )   Save The subway section between Yingmen Tan Station and Matan Station on Lanzhou Metro Line1 crosses the Yellow River at an upstream distance of 38~49 m from the Yintan Yellow River Bridge, with Matan Station located immediately adjacent to the riverbank. Influenced by upstream river turbulence and long-term sand-and-gravel excavation near the banks, several bored cast-in-place piles at the small-mileage end of the station were required to be constructed within deep artificial fills. Conventional bored-pile construction methods in these strata exhibited significant problems, including drilling-slurry loss, borehole instability, and related defects. This paper presents a case study of the enclosure-structure construction at the small-mileage end of Matan Station. The challenges associated with bored-pile installation in deep fills are summarized, and the underlying reasons for the difficulty in achieving stable pile formation in this soil layer are analyzed. Improvement trials were conducted to enhance pile-forming performance by adjusting slurry density, replacing the original slurry materials, and optimizing the drilling procedure. Results indicate that successful bored-pile installation in deep fills depends primarily on improving the self-stability of the fill layer while minimizing hydraulic connectivity between the borehole and surrounding ground. Finally, a soldier-pile installation scheme incorporating ground sleeve valve-pipe grouting reinforcement was successfully implemented. The engineering measures and practical experience obtained from this project provide valuable reference for similar underground works constructed under complex geological conditions. Related Articles | Metrics

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A Landslide Hazard and Slope Treatment in Wanning City CAO Wei 2026, 40 (3):  415-420.  Abstract ( 40 )   Save Wanning City, located on the southeastern flank of Hainan Island, has experienced rapid real-estate expansion driven by the province’s development as an international tourism destination. Intensive construction activities in mountainous terrain have resulted in large-scale slope excavation. Combined with the region’s humid maritime climate—characterized by annual precipitation exceeding 900 mm—these conditions have significantly increased the risk of landslides. Although engineered slope-support systems have been implemented in many developments, issues such as excessive structural displacement and localized support failure continue to occur due to construction deficiencies, design limitations, and adverse environmental factors. This paper presents a detailed case study of a mountain-slope support project in Wanning City. The investigation documents the landslide process, deformation characteristics of the support system, failure of ground anchors, and subsequent reinforcement measures. The findings provide practical insights and technical reference for similar slope-stabilization projects within Hainan Province. Related Articles | Metrics

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Construction Methods of Large Diameter Shield Structure Crossing Bridge Foundation of Parallel-Operated High-Speed Railway GE Zhaoguo 2026, 40 (3):  421-427.  Abstract ( 63 )   Save The control of ground settlement during shield-driven excavation has long been a critical technical challenge in tunnel engineering. This paper examines the Shanghai Rail Transit City Line Airport Liaison Line project as a case study. It focuses on the complexities associated with constructing an ultra-large-diameter shield tunnel in soft soil conditions, particularly where the alignment runs parallel to an operating high-speed railway with a very small clear distance and crosses beneath a river—conditions that impose stringent safety requirements. Two construction scenarios—unreinforced excavation and grouting-reinforced excavation—are evaluated. A refined three-dimensional numerical model is developed using the commercial finite-element platform MIDAS, and the simulation results are integrated with on-site monitoring data. This combined approach enables a systematic assessment of the deformation behavior of existing structures and the surrounding ground under the influence of the super-large-diameter shield excavation in soft strata. The findings indicate that rapid grouting and fast-setting slurry techniques effectively limit vertical deformation in the soil surrounding the shield tunnel. Additionally, the use of long-distance, large-area isolation piles significantly reduces soil disturbance within the pile zone, thereby controlling both differential and overall settlement of the high-speed railway bridge foundations. The specialized construction strategy—featuring tailored slurry properties, rapid grouting, and extensive isolation piling demonstrated to be both safe and appropriate for the project’s demanding conditions. Related Articles | Metrics

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Impact and Analysis of Subway Deep Excavation Construction on Nearby Buildings HU Weidong 2026, 40 (3):  428-431.  Abstract ( 68 )   Save The metro system greatly enhances urban development and daily travel, yet the excavation and construction required for underground station foundations inevitably influence the surrounding environment and nearby structures. To clarify how each stage of foundation-pit construction affects adjacent buildings, this paper examines the deep foundation pit project of Tianjin Metro Line No. 6 at Tianailu Station. Using on-site monitoring data, it evaluates the potential impacts of construction activities on nearby structures and proposes targeted control measures. The analysis shows that earthwork excavation, dewatering operations, and the installation of underground diaphragm walls can all contribute to settlement in surrounding buildings. Nevertheless, with well-designed and effectively implemented mitigation strategies, these negative effects can be substantially minimized, ensuring the safety and stability of nearby structural systems. Related Articles | Metrics

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Reasons for Deformation and Failure of Tower Foundation of a Transmission Line and Treatment Countermeasures ZHANG Hongbin, HU Xin, FAN Zhujun, LIU Zhiwei 2026, 40 (3):  432-436.  Abstract ( 40 )   Save To evaluate the deformation and failure of a transmission-line tower foundation and develop appropriate mitigation strategies, a comprehensive investigation was carried out using field measurements, surveys, subsurface explorations, and geophysical techniques. The study defined the extent of the foundation’s deformation, analyzed its underlying mechanisms, and identified the key contributing factors. Findings show that the deformation and failure resulted from creep-related sliding of the overlying permafrost in the slope direction, triggered by repeated freeze-thaw cycles. This represents a characteristic engineering-geological issue associated with special soil conditions in permafrost regions. Based on these results, two categories of countermeasures are recommended: rerouting the transmission line to avoid potential structural conflicts or implementing engineering treatments at the existing site to reduce frost heave and limit permafrost creep, thereby stabilizing the tower foundation. Related Articles | Metrics

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Aspects of Design and Construction of Large-Section Diversion Tunnels WEN Ping, ZHAO Yunlong, LIU Dahe, LI Gan 2026, 40 (3):  437-444.  Abstract ( 35 )   Save To overcome the challenges of low construction efficiency, high variability in surrounding rock conditions, and fault-induced water inrush risks in high-head, large-section diversion tunnels in Southwest China, a series of targeted technical innovations were developed. Three-dimensional geological modelling combined with real-time surrounding-rock classification enabled the creation of a graded equivalent elastic resistance coefficient system, which guided lining optimization. As a result, Class II/III floor lining thickness was reduced to 30 cm, and adjustments to reinforcement spacing—along with denser anchoring in Class V sections—achieved an 8% reduction in steel usage. Construction efficiency was significantly improved through new techniques, including a hydraulic lifting trolley (precision ±5 mm) and a bottom-arch sliding formwork system (flatness <5 mm), which together increased lining installation speed by 40%. Parallel excavation of the upper and lower tunnel sections further boosted monthly advance rates by 50%, shortening the overall construction schedule by three months. For the Fx1 fault zone, a double-layer pipe-shed system combined with high-pressure grouting reduced water inflow by 90%, while the use of a single-side-wall pilot tunnel method cut convergence by 80%, ensuring safe passage through the 214 m high-risk segment. Monitoring results show that surrounding-rock deformation has remained stable and lining stresses have stayed within safe design thresholds. These outcomes provide a strong technical reference for similar diversion-tunnel projects across Southwest China.  Related Articles | Metrics

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A Deep Excavation Support Design in Pebble and Red Sandstone Combined Strata TAN Yongwei, DI Guoen, 2026, 40 (3):  445-450.  Abstract ( 39 )   Save The geological conditions in the Lanzhou area are defined by a complex combination of large-particle, water-rich pebble strata and Tertiary hypabyssal red sandstone. A systematic evaluation was carried out to understand how the unfavorable characteristics of these formations-particularly the water-softening susceptibility of red sandstone and the high permeability and coarse particle size of cobble layers-affect support-system selection, groundwater control, and environmental protection. Corresponding engineering strategies were then developed to address these key technical challenges. Based on in-situ testing, a diaphragm wall was used for the first time in this region’s complex pebble strata. To prevent the traditional anchorage system from softening or disturbing the intact red sandstone outside the deep excavation, two 116 meter super-diameter ring bracing systems were implemented. A comprehensive groundwater-control scheme-centered on preventive, layered dewatering-effectively resolved issues related to the difficult dewatering of red sandstone and the protection of natural foundations. The successful completion of this project has significantly expanded the technical experience available for deep excavation engineering in Lanzhou and provides meaningful guidance for future projects in similar geological environments. Related Articles | Metrics

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Aspects of Remediation Design of a Municipal Roadway Slope Failure CAI Qing, LIU Baiqiang 2026, 40 (3):  451-455.  Abstract ( 44 )   Save This study examines a slopecollapse remediation project along a municipal roadway in Wuhan, focusing on failures driven by shallow sliding and archedfacing instability resulting from drainage system malfunction. To address these issues, a comprehensive treatment framework integrating slope stabilization, drainage optimization, and protective enhancement were developed. A combined reinforcement system—comprising grouted perforated pipes and reinforced-concrete vertical rib beams—was implemented to strengthen the collapsed soil mass and underlying cavity zones. This configuration significantly improved the mechanical integrity and global stability of the slope. Concurrently, interception and drainage ditches at the slope crest and intermediate platforms were rehabilitated and engineered to ensure effective diversion of surface runoff. Additional surface drainage holes were installed, forming a multi-layered waterproofing and drainage network that mitigates pore-water pressure buildup. The damaged arched facing was reconstructed and integrated with grid-grass vegetation, achieving a synergistic balance between structural protection and ecological restoration. Field monitoring indicates that the proposed approach effectively arrested slope deformation and ensured the long-term operational safety of the roadway. The findings provide valuable technical guidance and practical reference for similar urban road slope-collapse mitigation projects. Related Articles | Metrics

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Analysis of Geological Hazards Characteristics of Landslide in Sanxiyuan Village and Integrated Measures MAO Longdong, QIN He, XIA Kang 2026, 40 (3):  456-460.  Abstract ( 49 )   Save This study investigates the landslide hazard in Sanxiyuan Village through integrated on-site geological surveys and monitoring data analysis. The deformation characteristics, triggering mechanisms, and mitigation strategies of the landslide mass are systematically examined. Results indicate that the landslide is primarily distributed within interbedded sand-mudstone strata on 25°~40° slopes, exhibiting a dominant mode of traction sliding. During the June-September rainy season, the deformation rate increases markedly to 0.5~2 mm/d, approximately 3~5 times the rate observed in the dry season. The principal inducing factor is the significant rise in soil moisture following rainfall infiltration, with the maximum water content at the slope crest reaching 40.1% in July. Based on continuous monitoring, a combined mitigation system was implemented, including anti-slide piles, water-interception ditches, mixed locust forest ecological restoration, and a GNSS-based deformation monitoring network. After implementation, these measures reduced the maximum soil moisture content by 32.4%, 28.9%, and 27.1% (depending on slope position), decreased maximum horizontal displacement by 56.1%, and lowered maximum vertical settlement by 56.9%. The integrated engineering-ecological approach significantly enhances slope stability and provides a technical reference for landslide prevention and control in mountainous regions. Related Articles | Metrics

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Stability Analysis of Basal Heave of a Circular Foundation Pit ZHAI Gangjun, BAO Junji, WANG Yin 2026, 40 (3):  461-467.  Abstract ( 45 )   Save Basal heave analyses for circular foundation pits are commonly derived from two-dimensional upper-bound mechanisms that neglect three-dimensional spatial effects, resulting in failure surfaces that deviate from actual pit behavior. Building on the variable-mechanism upper-limit method and informed by numerical simulation, this study establishes a three-dimensional deformation mechanism for circular foundation pits subjected to backfill loading. A kinematically admissible velocity field is constructed to incorporate spatial effects, from which an upper-bound solution for the basal-heave safety factor is derived. Parametric analyses are conducted to evaluate the influence of pit radius, soil cohesion, and embedded-wall ratio on the basal-heave safety factor. Results indicate that incorporating three-dimensional effects significantly improves the accuracy of upper-bound predictions. The safety factor increases as pit radius decreases, reflecting the strengthening influence of spatial confinement; soil cohesion exerts a dominant, approximately linear effect; and excessive increases in embedded ratio yield diminishing returns in basal-heave resistance. A case study verifies the validity of the proposed formulation. The findings provide a more realistic theoretical framework for the design and construction of circular foundation pits, particularly where deformation control and basal stability are critical. Related Articles | Metrics

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Longitudinal Vibration of Large-Diameter Pipe Piles in Horizontally Isotropic Soil Layers ZHANG Wenxin 2026, 40 (3):  468-473.  Abstract ( 42 )   Save A longitudinal dynamic model for largediameter pipe piles is developed by integrating the constitutive behavior of horizontally isotropic materials with the viscoelastic motion equation for soil. To account for stratification effects and groundwater fluctuations, the surrounding soil is idealized as two layers: a horizontally isotropic single-phase medium and a horizontally isotropic saturated medium. The soil-plug response is represented using a Voigt model with added mass, while the lateral inertial effects of large-diameter piles are captured through the Rayleigh-Love rod formulation. Building on Novak’s thin-layer theory, saturated porous-medium theory, and existing analytical solutions for transversely isotropic single-phase soils, a coupled vibration equation is established for the pile-soil system comprising the pile (including soil plug), the single-phase soil layer, and the saturated soil layer. A closed-form theoretical solution for the pile-head dynamic response is subsequently derived. The analytical solution is implemented in MATLAB to perform pile-soil parameter analysis. Parametric studies reveal the governing influence of soil layering, saturation, viscoelastic properties, and pile geometry on the longitudinal vibration characteristics of large-diameter pipe piles. The findings provide a quantitative basis for evaluating dynamic pile behavior and offer guidance for engineering design involving layered and partially saturated ground conditions. Related Articles | Metrics

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Stress and Deformation Characteristics of Deep Excavation Adjacent to High Slope and Its Support System Design WAN Xin, ZHANG Jieqing, WANG Biao, LI Yidan, LUO Jin 2026, 40 (3):  474-478.  Abstract ( 50 )   Save This study investigates the coupled mechanical response of a super-high slope-deep excavation system in Huangpi District, Wuhan, using three-dimensional finite-element analysis to characterize stress redistribution and deformation evolution during staged excavation. Numerical results are compared with field monitoring data to evaluate the safety and reliability of the pile-anchor and pile-support system adopted for this project. Excavation-induced unloading alters the stress field of the adjacent slope, influencing its global stability, while the slope simultaneously imposes bias-pressure effects on the foundation pit. When the separation distance between the two is small, their deformation behaviors become strongly interactive: lateral displacement of the foundation pit exerts a pronounced traction effect on slope deformation. Engineering practice should therefore adhere to the principle of “stabilize the slope first, then strictly control foundation-pit deformation.” Project-wide monitoring and warning thresholds should be governed primarily by slope displacement criteria. Because the sidewall represents a rock-slope foundation-pit geological model, accurate investigation of rock mass structure, including weak interlayers and discontinuity orientations, is essential for both permanent and temporary support design. Qualitative geological assessment provides the fundamental basis for engineering judgment, while quantitative numerical analysis serves as a critical tool for comprehensive evaluation and design optimization. Related Articles | Metrics

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Influence Analysis of Material Parameters of Soil Reinforcement at the Launching End of Shielded Machine ZHANG Jiahe, WANG Chuang, MOU Jianhong, LI Pengfei, WANG Huinian, CUI Xiaopu, LIU Shurong, XIE Enlin 2026, 40 (3):  479-485.  Abstract ( 30 )   Save The study examines a shield-launching section in Baoding City and develops a three-dimensional stratigraphic numerical model using the finite-element platform ABAQUS. The model captures the evolution of vertical surface displacement during shield tunneling, and the simulated results show strong agreement with on-site monitoring data. Building on this validated model, a parametric sensitivity analysis is performed by increasing and decreasing the unit weight, elastic modulus, Poisson’s ratio, internal friction angle, and cohesion of the reinforced soil by ±20%. The corresponding changes in vertical surface displacement are then evaluated. The results indicate that variations in cohesion and Poisson’s ratio have minimal influence on surface deformation, whereas internal friction angle, elastic modulus, and unit weight exert significant effects. The relative sensitivity ranking is: internal friction angle > elastic modulus > unit weight. Based on these findings, an optimal parameter range for soil reinforcement is proposed. When the internal friction angle is 28°~32°, the elastic modulus is 95~105 MPa, and the unit weight is approximately 20 kN/m3, the excavation process demonstrates improved deformation control and enhanced construction safety. These results provide a useful reference for shield tunneling design in similar geological conditions. Related Articles | Metrics

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Influence of Plants on River Slope Erosion and Soil Strength LI Yang, ZHOU Jian, LI Yue 2026, 40 (3):  486-490.  Abstract ( 40 )   Save  With the intensification of global climate change and human disturbances, riverine ecosystems are increasingly threatened by severe slope-erosion processes. This study evaluates Magnolia multiflora and Cynodon dactylon as slope-protection species by examining their root-system development, tensile properties, and reinforcement effects on soil shear strength across distinct growth stages. The influence of rainfall on slope runoff velocity and sediment yield under each vegetation type is further assessed. Results demonstrate that the interwoven distribution of roots within clay soils markedly enhances soil shear strength, primarily through increased cohesion, with M. multiflora exhibiting a stronger strengthening effect than C. dactylon. Vegetated slopes covered by M. multiflora and C. dactylon reduce runoff velocity by 35.38%~45.53% and 45.11%~52.55%, respectively. Correspondingly, sediment yield decreases by 59.2%~94.33% under M. multiflora and 45.88%~86.82% under C. dactylon. While C. dactylon provides superior sediment-reduction performance, M. multiflora contributes more substantially to improving soil shear resistance. Both species exhibit strong potential for slope stabilization and erosion mitigation, indicating that vegetation selection in engineering applications should be guided by local climatic and hydrological conditions. Related Articles | Metrics

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Deformation Analysis of Double-Row Buttress Pit by MIDAS GTS NX Simulation LI Yanjun, LIU Honggu 2026, 40 (3):  491-494.  Abstract ( 60 )   Save Based on an engineering case study, a three-layer cross-brace support system with double-row piles was modeled using MIDAS GTS NX to analyze the behavior of the internal support structure. Numerical simulation results were compared with field monitoring data to identify the deformation characteristics of the retaining system. The findings show that horizontal displacement is concentrated in the central portion of the excavation, exhibiting a “small at both ends and large in the middle” pattern. At the initial stages, excavation depth and displacement are positively correlated; when the excavation reached 12.5 m, pile displacement peaked and subsequently decreased, reaching a minimum near the pile toe. The MIDAS numerical model predicted maximum lateral deflections of the front and rear pile rows that were 17.6% and 16% higher, respectively, than the measured values. The horizontal displacement of the front row piles was slightly greater than that of the rear row piles, likely due to soil deformation during excavation. The front row piles may experience greater compression and distortion, resulting in larger displacements compared with the rear row piles. Related Articles | Metrics

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Back Analyzed Shear Resistance and Reinforcement of Debris Slope 2026, 40 (3):  495-497.  Abstract ( 33 )   Save The determination of shear-strength parameters in geotechnical materials is crucial for analyzing slope stability and designing landslide reinforcement. The back-analysis method effectively compensates for the limitations of laboratory and in-situ testing and is therefore widely used due to its practicality and reliability. For gravelly soil slopes, stability and reinforcement analysis must focus on two key conditions: (1) the reduction in shear strength under water-saturated conditions, and (2) the need to adopt residual (post-peak) strength after sliding occurs. The variation of strength parameters under these conditions depends on factors such as gravel content and soil density, and no unified theoretical method currently exists. Thus, back-analysis can be used to determine these parameters. Based on an engineering case study, back-analysis was applied to quantify the reductions in cohesion c and friction angle φ after saturation, as well as the reduction from peak strength to residual strength. Results show that the shear strength of gravelly soil decreases significantly upon saturation, with cohesion exhibiting the largest reduction. After sliding deformation, the residual strength is approximately 75% of the peak strength. These findings provide useful guidance for the design and reinforcement of similar slopes. Related Articles | Metrics

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Influence of Borehole Drilling with Slurry on the Slope Stability YUAN Hang, LU Hao, LI Shuai 2026, 40 (3):  498-501.  Abstract ( 43 )   Save The influence of large-diameter slurry-supported bored-pile excavation on slope stability is investigated using a rapid-transit bridge foundation project as a case study. A numerical model is established to analyze the evolution of slope deformation and safety factors during different stages of pile-hole excavation. The results indicate that excavation in the early stages significantly reduces the safety factor of the slope above the pile-top platform, while the impact diminishes in later stages. When the pile hole is located near the rear edge of the slope and maintains sufficient distance from the slope crest, its effect on that slope grade is relatively small. Excavation may alter the failure mode or shift the weak zones of the slope, requiring dynamic control and appropriate monitoring during construction. In engineering practice, pile holes should be positioned away from the slope toe, and casing pipes should be embedded to pass through weak soil layers. When the pile hole is located at the rear edge of the slope, the distance between the hole and the slope crest should be at least three times the pile diameter. Related Articles | Metrics

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Impact of Deep Excavation on Adjacent Completed Basements SHI Haitao, HUANG Wenbin, LIU Dong, 2026, 40 (3):  502-506.  Abstract ( 44 )   Save The excavation of deep foundation pits has become increasingly common in urban development, and their influence on adjacent structures has emerged as a critical concern. Focusing on a deep excavation support project in Shenzhen located near an existing basement structure, a three-dimensional numerical model was established using finite-element analysis software to evaluate the impact of excavation on the adjacent basement. The study shows that as the support system deforms progressively during excavation, the nearby basement undergoes corresponding horizontal deformation and vertical deformation. Deformation reaches its maximum when the excavation reaches the final depth, with peak values occurring along the basement sidewall closest to the pit. Analytical results indicate that the deformation induced by this excavation remains within acceptable control limits. To further ensure deformation control, it is recommended to increase the stiffness of the support system in the central sections or enhance the mechanical properties of the surrounding soil. During construction, strict quality control, enhanced monitoring, and adaptive construction management are essential to maintain the safety of the adjacent basement. Related Articles | Metrics

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Influence of Deep Excavation on Deformation of Adjacent Building using Numerical Analysis LI Zhuangzhuang, JIANG Haiqing 2026, 40 (3):  507-511.  Abstract ( 39 )   Save Rapid urban development in China has led to an increasing number of high-rise and super-high-rise buildings, accompanied by a growing volume of deep excavation projects. The influence of foundation-pit excavation on adjacent structures has therefore become a critical concern. Based on the design, site investigation, and monitoring data from a foundation-pit support project in Shenzhen, a three-dimensional numerical model of the pit and surrounding buildings/structures was established using MIDAS/GTS. The model was used to simulate and analyze deformation and potential damage to nearby buildings, and the numerical results were compared with field monitoring data. The findings indicate that excavation induces varying degrees of displacement, settlement, and tilting in adjacent buildings. Greater excavation depth and shorter distance to the pit correspond to more pronounced building deformation. The numerical results satisfy relevant code requirements, and the data provide useful reference value for subsequent design, construction, and monitoring work. Related Articles | Metrics

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Correlation between Shield Tunneling Parameters and Granite Strata with Different Degrees of Weathering XU Nanjun, WANG Ruoying, LIANG Zhenbi, LIU Huaiyu, ZHOU Xiaowen 2026, 40 (3):  512-517.  Abstract ( 76 )   Save This study examines the shield tunnel between Xinyuan Road Station and Dongcheng South Station in Dongguan as the engineering background. Using field monitoring data and statistical analysis methods, it systematically investigates the correlation characteristics between six key EPB shield tunneling parameters and four categories of granite strata with different degrees of weathering. The results show that: (1) The degree of granite weathering is a major factor influencing shield tunneling parameters, and each stratum exhibits distinct parameter patterns. (2) Within granite formations, the total thrust of the shield machine shows a strong linear correlation with the reciprocal of cutterhead penetration; the advance rate and cutterhead penetration also exhibit a strong linear correlation; meanwhile, cutterhead torque and chamber pressure show no obvious correlation. The findings provide guidance for the reasonable selection and optimization of tunneling parameters for similar shield machines operating in granite residual soil strata. Related Articles | Metrics

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Parameter Optimization and Deformation Control of Integrated Double-Row Piles and Passive Zone Reinforcement in Soft Soil XIONG Zonghai, XIONG He, XIE Wujun, ZHANG Xiaohua, ZHANG Hongzhang 2026, 40 (3):  518-524.  Abstract ( 49 )   Save For the deformation-control challenges of deep excavations in the soft-soil regions of Wuhan, this study examines a residential project in Hongshan District as a case background. To quantify how passive-zone reinforcement parameters influence support deformation, PLAXIS finite-element software was employed. The Mohr-Coulomb and Hardening Soil constitutive models were used to represent the mechanical behavior of the reinforced soil mass and the surrounding soft soil. Through parametric analysis, the study systematically investigates how reinforcement width (2~14 m), height (2~12 m), and cross-sectional configuration (horizontal and vertical rectangles, as well as stepped forms at the top or bottom) regulate the lateral displacement of a double-row pile support system. Results show that increasing reinforcement width significantly suppresses pile lateral movement, with the displacement-reduction effect stabilizing once the width reaches approximately 8 m. Considering both control efficiency and economic performance, 8 m is identified as the optimal reinforcement width for this project. Reinforcement height performs best within the 6~8 m range; beyond 8 m, improvements diminish because deeper soil layers possess better inherent properties. Regarding reinforcement configuration, vertical rectangular sections outperform horizontal ones for the same reinforcement volume, stepped configurations are more economical than simple rectangles, and bottom-stepped reinforcement provides the most effective control. A combined reinforcement scheme—bottom-stepped configuration, 8.65 m width, and 6 m height—is proposed, which limits the maximum lateral displacement of the support piles within code-specified limits and satisfies overall deformation-control requirements. The findings offer quantitative guidance for passive-zone reinforcement design in deep excavations within similar soft-soil environments. Related Articles | Metrics

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Statistical Damage Constitutive Model for Rock under Triaxial Compression with Thermal Coupling XU Lantao, XIE Jinbo 2026, 40 (3):  525-530.  Abstract ( 39 )   Save Under the influence of external factors, micro-cracks and pores develop within rock materials. Continuous damage mechanics define these internal micro-defects and investigates the physical and mechanical behavior of rock under damaged states. Within the theoretical framework of continuous damage mechanics, and based on the Mohr-Coulomb criterion, a statistical damage model is established by coupling power-law and exponential damage formulations, and its applicability and accuracy are verified. The main work includes two aspects: first, the classical coupling form and the exponential coupling form are compared, and their respective abilities to characterize stress-strain curve features are analyzed. Second, a suitable random variable for the micro-element strength distribution is derived based on the Mohr-Coulomb criterion so that the probability function satisfies the domain requirements of the random variable. On this basis, a constitutive equation is constructed and subsequently validated. The results provide a solid theoretical foundation for further engineering applications of statistical damage-based research. Related Articles | Metrics

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Crack Evolution and Safety Assessment of Existing Cut-and-Cover Tunnel Lining under Slope Collapse ZHANG Hanghua, YAO Lei 2026, 40 (3):  531-534.  Abstract ( 36 )   Save During the construction of mountain tunnels, slope-collapse incidents above the tunnel portal and cut-and-cover sections occur with notable frequency. Using the cut-and-cover segment of a highway tunnel in a mountainous region as the engineering context, this study investigates a localized rockfall event that occurred on the southeastern side slope. A 1 m longitudinal equivalent finite-element model is developed to represent three representative conditions: (1)the pre-collapse state, (2)the instantaneous dynamic impact induced by the collapse, and (3)the post-collapse condition following debris removal and re-leveled backfill. The analysis systematically examines the crack-width distribution and the evolution of internal forces within the lining structure under each condition. The findings indicate that, under the original undisturbed condition, the cut-and-cover lining is governed primarily by axial compressive forces, with crack widths remaining small and locally manageable. The collapse-induced impact markedly increases tensile demand at the arch foot and arch crown, causing the maximum crack width to exceed the limits prescribed by relevant design codes and revealing a potential risk of brittle structural failure. After the backfill is re-leveled, a more stable uniformly distributed load is reestablished, resulting in a significant reduction in crack width and restoring compliance with code requirements. The structural stress state consequently returns to a stable condition. These results provide a valuable reference for the assessment and mitigation of similar engineering accidents. Related Articles | Metrics

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Analysis of the Impact of the Cross Channel Bridge Project on Slope Stability SUN Wanlin, HU Bo, QIU Jinwei 2026, 40 (3):  535-540.  Abstract ( 49 )   Save To address the influence of constructing the cross-Yinjiang-Jihuai super bridge on the stability of canal-section slopes, and in view of the complex engineering-geological conditions, a limit-equilibrium analytical framework was employed. During the excavation and backfilling of the main-pier foundation pit, the stability of the left and right canal slopes at the bridge-crossing location was evaluated under multiple loading scenarios, including bridge loads, vehicular loads, and seismic actions. The study systematically elucidates the mechanisms and extent to which bridge construction under complex geological conditions affects the stability of canal slopes composed of mudstone containing weak interlayers. Computational results indicate that, under existing stratigraphic conditions and the current construction plan, the safety factor of the canal slopes during the construction stage exceeds 1.2. However, if rainfall or other factors induce further softening of the mudstone, the safety factor may decrease to 1.109, demonstrating that the bridge construction exerts an adverse effect on slope stability and introduces potential safety hazards. A comparative assessment of the two canal banks shows that the left slope exhibits a lower safety factor than the right. This disparity is primarily attributable to geological factors: field investigations revealed that mudstone fracture surfaces on the left slope dip in the downslope direction, whereas those on the right slope dip counter to the slope. Related Articles | Metrics

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Effect of Lignin Fiber on Water Stability of Red Clay LIU Baochen, WANG Xiaobo, ZHOU Haofeng, YANG Bai 2026, 40 (3):  541-545.  Abstract ( 42 )   Save To investigate the influence of lignin on the water-stability performance of red clay, this study conducted indoor wetting-disintegration tests and performed a systematic analysis on lignin-fiber-reinforced red clay, from which corresponding disintegration curves were obtained. The results show that, without curing, the incorporation of lignin weakens the water-retention capacity of red clay and reduces its water stability. As the lignin content increases, the disintegration time of red clay exhibits a general increasing trend. For cured specimens, the disintegration amount decreases progressively with higher lignin-fiber content, and a relatively stable disintegration process is observed within the first two hours, although complete disintegration does not occur. The study further reveals that curing age has a significant effect on the water stability of red clay: with longer curing periods, the soil’s water stability improves and its resistance to disintegration increases. In uncured specimens, the average disintegration rate first increases and then decreases with rising lignin-fiber content. In contrast, after curing, the average disintegration rate decreases steadily as lignin content increases. An inverse relationship is observed between the average disintegration rate and curing age. Related Articles | Metrics

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Influence of Clay Content and Saturation on P-wave Velocity of Silt-Clay Mixture SHAN Yangyang, SHI Wei, MENG Xiangmei, YANG Zhongnian, XU Zhengyi , LING Xianzhang, 2026, 40 (3):  546-551.  Abstract ( 37 )   Save The study investigates the acoustic properties of siltclay mixed soils with different clay-particle contents (CC) from a geomechanical perspective through laboratory testing, focusing on how clay content and saturation influence P-wave velocity in the Yellow River Delta. The results show that increasing clay-particle content hinders P-wave propagation in the soil. Under fully saturated conditions, higher excitation frequencies correspond to higher P-wave velocities. When specimens are in a near-saturated state, the rate of change in P-wave velocity differs when clay contents reach 20% and 40%, and higher clay content produces a stronger influence on P-wave velocity. This phenomenon is related to porosity, which increases nonlinearly with clay content; at 20% and 40% clay content, the rate of porosity change also increases. Variations in porosity are associated with the distribution of clay particles within the pore space. The Thomas-Stieber model is used to analyze the spatial distribution of clay, providing a microscopic interpretation of how clay exists within pores at different clay-particle contents. Related Articles | Metrics

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Experimental Study on the Physical and Mechanical Properties of Red Clay Contaminated with Alkaline Solution (NaOH) LONG Yu, CHEN Yun, WANG Lianrui 2026, 40 (3):  552-558.  Abstract ( 29 )   Save To investigate in depth the influence of alkaline solution (NaOH) on the physical and mechanical properties of red clay, undisturbed red clay samples were immersed in six NaOH solutions of different concentrations and cured for varying durations. By testing the physical-mechanical indices of alkali-contaminated red clay and conducting indoor simulation experiments, the relationships among physical-mechanical behavior, alkali concentration, and curing time were established. The main findings are as follows: 1) Physical properties of alkali-contaminated red clay are primarily controlled by NaOH concentration. As concentration increases, dry density decreases, specific gravity increases, the liquid limit decreases then increases, and the plastic limit increases then decreases. 2) The mechanical properties exhibit a clear concentration effect. With increasing NaOH concentration, the shear strength first decreases, then increases, and finally decreases again. Before curing, the shear strength is lowest at 3.5%, indicating completion of reactions involving active cementitious substances. Further increases in concentration lead to strength recovery, but at 21%, shear strength decreases again. After 10 days of curing, shear strength increases across all concentrations, with the most pronounced improvement at 14%. 3) An optimal concentration range exists for shear strength of alkali-contaminated red clay: performance is worst at 3.5% and best at 14%. 4) Alkali-contaminated red clay requires a certain curing period to allow newly formed cementitious products to fill pores, thereby increasing density and strength. Related Articles | Metrics

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Laboratory and Field Shear Experimental Study on Completely Weathered Granite HU Ping 2026, 40 (3):  559-563.  Abstract ( 38 )   Save Completely weathered granite exhibits distinctive engineering behavior, making it difficult to obtain its shear-strength parameters using conventional methods. At present, most researchers determine shear strength through direct shear tests and triaxial shear tests, yet these approaches often overlook the influence of specimen size on geomaterial strength and weaken boundary effects. As a result, the derived shear-strength parameters tend to be higher than those under actual field conditions, which may compromise engineering safety. By comparing results from large-scale in-situ direct shear tests with those from conventional laboratory direct shear tests on undisturbed samples and further comparing direct shear results of remolded completely weathered granite specimens of different sizes, this study analyzes the discrepancies in shear-strength parameters obtained under various indoor and outdoor shear conditions. The test results indicate that cohesion c decreases with increasing specimen size, while the internal friction angle φ shows an increasing trend. Additionally, the strength of undisturbed samples is greater than that of remolded samples. These findings demonstrate that soil structure and specimen size exert significant influence on the shear strength of completely weathered granite. Related Articles | Metrics

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Experimental Study on Shear Mechanical Properties of Silt-Cement Soil Interface JIANG Xiaotian, WANG Hai, LI Xikai, LI Yonghui 2026, 40 (3):  564-569.  Abstract ( 37 )   Save To investigate the shear mechanical behavior at the siltcemented soil interface, a series of interface shear tests were conducted using a self-developed large-scale interface shear apparatus. The effects of multiple factors on the shear mechanical properties of the silt-cemented soil interface were analyzed. The results show that the interface shear stress-displacement relationship exhibits an elasto-plastic trend, but no residual stage appears when the silt is saturated. During interface shearing, the silt displays dilatancy, which becomes more pronounced under higher normal stress; increased interface roughness enhances dilatancy when the silt has a relatively low water content. Increasing normal stress, increasing interface roughness, and decreasing water content all contribute to higher interface shear strength. The interface shear failure conforms to the Mohr-Coulomb criterion. The study also clarifies the relationship between peak and residual interface shear strength under unsaturated conditions. These findings provide a useful reference for analyzing the stress and deformation behavior of cement-soil structures embedded in silt in practical engineering. Related Articles | Metrics

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Unconfined Compressive Strength Testing Study of Construction Sludge Solidified with Fly-Ash-Based Geopolymer ZHANG Lei, ZHANG Bohang, LIU Jing, HANG Yue 2026, 40 (3):  570-573.  Abstract ( 45 )   Save The study investigates the factors influencing the unconfined compressive strength (UCS) of geopolymer-stabilized construction spoil. Using fly ash as the primary raw material and NaOH as the alkaline activator, geopolymer binders were prepared to solidify spoil generated from foundation-pit excavation. The effects of alkali-activator dosage, curing temperature, and curing duration on the UCS of the stabilized soil were analyzed. The results show that the UCS of the stabilized soil increases rapidly at first and then more slowly—and may even slightly decline—as the activator dosage, curing time, and curing temperature increase. The greatest strength improvement occurs when the activator dosage is 19%, the curing time reaches 16 hours, and the curing temperature is maintained at 60℃. Hydration reactions between fly ash and the alkaline activator generate silicate and aluminate hydration products, which enhance the strength and stability of the stabilized soil through precipitation, adsorption, and pore-filling mechanisms. Related Articles | Metrics

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Experimental Study on Properties of Tensile Strength of High and Low Density Compacted Expansive Soil LV Huabing, QIN Guanhua, ZHANG Hongri, GUO Ou, WANG Lei, CHEN Zhi 2026, 40 (3):  574-579.  Abstract ( 32 )   Save To investigate the tensile-strength mechanical parameters of expansive soil and to clarify the mechanism governing tensile-strength variation under different compaction densities, a series of tensile tests was conducted on high and low-density compacted expansive soils using an improved strain-controlled triaxial apparatus. The mechanical characteristics of tensile strength were systematically examined. In addition, SEM testing was employed to analyze the microstructural mechanisms underlying the strength differences between high and low density expansive soils. The results indicate that, at a constant water content, the tensile strength of expansive soil first increases and then decreases with changing dry density. Under the same dry density, increasing water content produces a similar trend in tensile strength. Although high and low density expansive soils exhibit comparable patterns of tensile-strength variation, they differ significantly in strength magnitude and failure mode. High-density expansive soil predominantly undergoes brittle tensile failure, whereas low-density expansive soil exhibits ductile tensile failure. The observed variations in tensile-strength behavior arise from the combined effects of capillary pressure, cementation, seepage, shrink-swell behavior, and microscopic physical mechanisms. Related Articles | Metrics

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Tensile Strength of Expansive Soil Under Different Moisture Content LIN Haihua, HUANG Junhui 2026, 40 (3):  580-583.  Abstract ( 45 )   Save Investigating the tensile strength of expansive soil helps clarify its crack-evolution behavior and holds significant value for road engineering applications. Using a newly developed tensile apparatus, tensile-strength tests were conducted on Ningming expansive soil at a constant dry density but with varying water contents to examine in depth how moisture conditions influence tensile behavior. To further elucidate the swelling mechanism of Ningming expansive soil, scanning electron microscopy (SEM) was employed to observe the microstructure of the specimens. Test results show that the tensile strength of the soil increases markedly with rising water content; however, when w>10.53%, the rate of strength increase diminishes. The clay minerals in the soil exhibit a plate-like morphology, which greatly enlarges the specific surface area of soil particles and enhances their hydrophilicity. In addition, water filling the pores between the larger structural units formed by the interbedding of plateshaped clay minerals affects both the matric suction and capillary suction of the specimens. Related Articles | Metrics

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Application of Sand Fill Method in Determining of Degrees of Compaction of Highway Embankments YUAN Pengju, HAO Jiafu, QI Songsong, CHEN Longyang, ZHU Lumeng, LIU Peng 2026, 40 (3):  584-587.  Abstract ( 49 )   Save For the challenges associated with silty-soil subgrade—including difficulty in achieving adequate compaction and deviations in compaction-degree test results—this study examines a construction project involving a silty-soil embankment. Through particle-size analysis, light compaction tests, and related laboratory experiments, key parameters such as grain-size distribution, Atterberg limits, and maximum dry density were obtained. The sand-cone method was adopted as the in-situ testing technique for evaluating subgrade compaction. A systematic analysis was conducted on the application of the sand-cone method, covering its working principle, sand-cone apparatus, selection of calibration sand, and operational procedures. The method’s applicability and the actual compaction performance of the subgrade were verified using field test results. The findings indicate that the maximum particle size of the silty soil in the test section is less than 13.2 mm; therefore, a 10 cm diameter sand cone is appropriate for compaction testing. Calibration sand with a particle size of 0.15~0.3 mm yields the smallest dispersion in calibration results. As the number of roller passes increases, the degree of compaction also increases, though the incremental gain per pass gradually decreases. After sufficient rolling, the achieved compaction meets the requirements for subgrade performance. Related Articles | Metrics

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Analysis of Pore Structure Characteristics of Red Sandstone in Western Hubei Using NMR HUANG Qilong, BAI Wei, WANG Feng, CHEN Wenqiang, LI Tianguo, XI Xiaorui, 2026, 40 (3):  588-592.  Abstract ( 42 )   Save Red sandstone exhibits pronounced variability in strength and diverse disintegration behaviors, with its pore structure serving as a key factor governing macroscopic mechanical properties. To clarify the intrinsic relationship between pore structure and strength, red sandstones of different strength grades collected along the E’xi Xiangyi Expressway were selected as research objects. Nuclear Magnetic Resonance (NMR) was used to systematically characterize their pore features, and saturated uniaxial compressive strength tests were conducted to analyze how pore characteristics influence mechanical strength. The results show that red sandstone with the lowest porosity and smallest pore size exhibits the highest strength. When porosity is approximately the same, larger pore size corresponds to lower strength, indicating that pore size is also an important factor affecting the mechanical behavior of red sandstone. The findings provide essential data on pore characteristics across red sandstones of varying strengths and offer a useful reference for the design and stability evaluation of redsandstone subgrade engineering along the Xiangyi Expressway. Related Articles | Metrics