Current Issue

2025, Volume 39,  Issue 4

2025, 39(4): .
Abstract:
2025, 39(4): 1-3.
Abstract:
Review and Prospect
Research progress on hydraulic and mechanical properties of red beds
Gan Jizhong, Zhang Xuan, Chen Dun, Mu Yanhu, Mao Yuncheng, Zhang Wei, Zhang Kun, Ning Longqing
2025, 39(4): 475-486. doi: 10.20265/j.cnki.issn.1007-2993.2024-0436
Abstract:
The red bed is a red sedimentary rock composed of sandstone, conglomerate, shale and argillaceous rocks, which is widely distributed in the southeastern, southwestern, and northwestern China. Due to its characteristics of poor stress, easy weathering, poor water rationality and easy disintegration, its road performance is poor, which seriously threatens the long-term stability of founda tion engineering in red bed area. The water physical and mechanical properties of red beds are summarized through literature research. The water physical properties of red beds are introduced from the aspects of water swelling, disintegration, softening and permeability. The static characteristics of red beds are summarized through strength and deformation analysis. The research progress of red bed dy namics is summarized from the aspects of dynamic parameters, dynamic strength and cumulative deformation, and the development trend is prospected.
Technology Development and Innovation
Effect of crack surface slip and shear dilatation on damage and failure of rocks
Liao Zhiyi, Qi Chengzhi
2025, 39(4): 487-496. doi: 10.20265/j.cnki.issn.1007-2993.2024-0414
Abstract:
The current research on the impact of slip and dilatancy along fissure surfaces in discontinuously fractured rock masses on rock damage and failure is insufficient. This study improves the macroscopic damage model of rock masses in two aspects by employing fracture and damage mechanics. Initially, we considered that during slip under uniaxial compression, the irregular rough asperities on the fissure surface cause frictional energy loss. Secondly, based on the Bardon dilatancy model, we took into account the fact that closed sliding fissures generate certain normal dilatancy displacement, resulting in the loss of strain energy. Furthermore, using the Mohr-Coulomb rock micro-element strength criterion and assuming that the micro-element strength follows a Weibull distribution, a meso-damage model for the rock mass was constructed. Finally, based on Lemaitre's strain equivalence hypothesis, a macro-meso coupled damage model was developed, considering fissure slip and dilatancy. Comparison with experimental data shows that this model can show the uniaxial compression mechanical behavior of rock masses well. The analysis of parameter sensitivity of such parameters as the inclination, length, internal friction angle, and dilatancy angle of rock fissures demonstrates that considering slip and dilatancy along fissure surfaces is crucial for studying the uniaxial compression mechanical properties of rock masses. This research provides a reference for accurately explaining the physical and mechanical behavior of fissure surfaces in fractured rock masses under uniaxial compression.
Shape optimization of tunnel section based on the homogenization distribution of surrounding rock strain energy
An Xuexu, Guo Xintian, Huang Rongbin, Tao Lei
2025, 39(4): 497-503. doi: 10.20265/j.cnki.issn.1007-2993.2024-0283
Abstract:
The selection of tunnel section shape directly affects the stability of its surrounding rock. Based on the complex variable function theory and the mixed penalty function method, a shape optimization criterion was proposed that the maximum average strain energy of the tunnel reached the minimum from the perspective of the relationship between the strain energy distribution of the tunnel and its failure characteristics. Combined with the engineering geological data of the deep hard rock tunnel from Hanjiang River to Weihe River, the effects of the radial strain energy calculation range and ground stress on the optimized tunnel section shape were investigated. The results show that: when using the shape optimization criteria developed to optimize the deep horseshoe tunnel, the radial strain energy calculation range should exceed 2.0 times the maximum tunnel radius. For tunnels with limited section width, the criterion significantly improved the uneven strain energy distribution, and the lateral pressure coefficient exhibited a stronger influence on the optimized section shape and overall distribution of surrounding rock average strain energy. When the width and height of the tunnel section are limited, this optimization criterion has limited effect on improving the uneven distribution of the surrounding rock strain energy of the tunnel, and the lateral pressure coefficient has little effect on the optimized section shape, but has a greater impact on the overall distribution of the surrounding rock average strain energy.
Improved calculation method for settlement of rectangular pipe jacking based on random medium theory and Peck formula
Shen Qingsong, Chen Ye, Ye Shenghua, Ji Qiaowei, Wang Qiang
2025, 39(4): 504-510. doi: 10.20265/j.cnki.issn.1007-2993.2024-0214
Abstract:
The calculation of the settlement caused by pipe jacking has always been a critical aspect in the design of pipe jacking engineering. The commonly used Peck formula was summarized on the basis of a large number of circular pipe jacking, and there are some errors in the application of rectangular pipe jacking. The random medium theory, which is suitable for both circular and rectangular pipe jacked, only gives the integral formula without the final integral calculation result, which leads to the complex calculation process and is difficult to be applied in engineering design. This study improves the integrand function in the random medium theory, proposes a simpler approximation function, and derives the final integration result, which greatly simplifies the calculation process. The relative error between the calculated result of the improved method and the measured settlement value (except for some measuring points) is approximately 5%, which indicates that the improved method demonstrates reasonable accuracy. The improved method was used to analyze the influence of various factors on the surface settlement, which provides a reference for future engineering design.
Engineering Practice and Application
Mechanical performance of prefabricate RC foundation of high voltage substation frame considering foundation-soil-structure interaction
Pang Rui, Duan Meinan, Xiao Bo, Liu Yanghang, Dong Zhu
2025, 39(4): 511-522. doi: 10.20265/j.cnki.issn.1007-2993.2024-0108
Abstract:
To study the mechanical performance of prefabricated reinforced concrete (RC) foundation of substation frame, the foundation-soil-structure interaction (FSSI) model, the foundation-structure interaction (FSI) model, foundation-soil model and foundation fixed model were established by ABAQUS software. Considering the adverse wind conditions under the bearing capacity limit state, the structural responses of each component in the four models were compared and analyzed, and the simulation analysis method of the prefabricated foundation was optimized. The results show that under the unfavorable wind conditions, the stress and deformation of each component of the prefabricated foundation and the herringbone frame in the FSSI model are in the elastic stage, which meets the design requirements. Under the four model conditions, when the influence of soil is not considered, the stress distribution of the prefabricated foundation is uneven and the value is small, the vertical displacement and deformation are almost zero, the stress of the main control nodes of the herringbone frame is large and the displacement is small. When the synergistic deformation of the whole structure is not considered, the stress of the prefabricated foundation concrete and the steel bar is small; considering the foundation-soil-structure interaction, the stress, displacement and deformation of the prefabricated foundation increase, and the along-wind displacement of the herringbone frame increases. This analysis method is more in line with the actual stress and is conducive to the safety design of the prefabricated foundation. If the arrangement of the herringbone frame is consistent and the simplified modeling method of applying equivalent load is used to design the foundation, the reinforcement amount of the prefabricated three-column foundation and the double-column foundation should be increased by about 60% and 27%, respectively.
Numerical analysis of bearing capacity and conversion coefficient calculation of O-cell test of pipe pile in marine soft clay foundation
Zhang Junjing, Jiang Rui
2025, 39(4): 523-529. doi: 10.20265/j.cnki.issn.1007-2993.2024-0124
Abstract:
Compared with traditional methods, O-cell test has unique advantages for some special sites, especially in the offshore pile foundation testing. To study the load transfer characteristics of the O-cell method for testing piles in coastal soft soil foundation, and analyze the influence of pile parameters on the conversion coefficient, this paper established the pile-soil numerical model to simulate the O-cell and traditional pile testing processes. The finite element method and equal displacement method were combined to calculate the conversion coefficient and ultimate bearing capacity, and the influence of pile parameters on the conversion coefficient was discussed. The research results indicate that the error between the equivalent conversion ultimate bearing capacity calculated by introducing the equal displacement method into the O-cell pile-soil model and the calculation results of the surcharge method is within 0.5%, and the O-cell conversion coefficient can be accurately calculated. The increase of the length and diameter of the pipe pile will significantly improve the bearing capacity of the pile foundation, and the pile parameters have a significant impact on the O-cell conversion coefficient and the ultimate bearing capacity of the pile foundation.
Determination of the groundwater level for anti-floating in the Tianjin area
Du Zhanlei, Liu Xiaolei
2025, 39(4): 530-536. doi: 10.20265/j.cnki.issn.1007-2993.2024-0273
Abstract:
According to the long-term observation data of groundwater in the Tianjin area, the current situation and dynamic change law of groundwater level in the Tianjin area were systematically analyzed. The maximum groundwater level in the central urban area of Tianjin was predicted by using the GM (1,1) grey prediction model, and the variation of the maximum water level elevation in the Tianjin area and the recommended anti-floating level were given. The determination method of anti-floating water level in mountainous and hilly areas, accumulation plain areas, coastal intertidal zones, and special areas in northern Tianjin was quantitatively analyzed, and the regional empirical value of anti-floating water level was given. The results show that: (1) the maximum groundwater level elevation in Tianjin in 2023 is 1.0~7.0 m, and the buried depth is 1.0~3.0 m, which is consistent with the distribution range and trend of the maximum groundwater level from 2019 to 2023. (2) The variation trend of the predicted water level in the central urban area is consistent with the original observation water level, and most areas show a downward trend. The anti-floating water level elevation is generally 1.8~3.6 m, which is generally high in the northwest and southeast, and low in the northeast and southwest. (3) For areas with low elevation without data such as the surrounding area of Tianjin city, the anti-floating water level can be taken as 0.50 m below the designed outdoor floor elevation. For areas with low-lying terrain, high ground filling, and low ground excavation, the anti-floating water level should be taken as the designed outdoor floor elevation.
Stability and environmental restoration of informal construction landfills
Yang Yonghui, Liu Qingjuan, Gao Debin
2025, 39(4): 537-542. doi: 10.20265/j.cnki.issn.1007-2993.2024-0203
Abstract:
The remediation of informal construction-waste landfills is currently one of the important research topics for environmental restoration. Field investigations, surveying, drilling, and laboratory experiments were conducted in Xi’an Qingcaigou construction landfills, and the geological environment along with the morphology and deformation characteristics of the landfills were analyzed. FLAC 3D was used to analyze the stability of the slope under different conditions. The environmental risk of construction waste was also studied. A capillary barrier layer scheme for constructing landfills using recycled aggregates and waste soil from construction waste has been proposed, providing a scientific basis for environmental restoration and management of informal construction waste landfills.
Deformation characteristics of high-fill temporary storage yard foundation on complex soft soil
Wang Wenhui
2025, 39(4): 543-549. doi: 10.20265/j.cnki.issn.1007-2993.2024-0192
Abstract:
Based on a large-scale high-fill temporary storage yard project on a complex soft soil foundation in a coastal area, the consolidation and deformation characteristics of soft soil foundation under high-fill load were studied by conducting in-situ monitoring and finite element analysis of pore water pressure and deformation of soft soil foundation under the condition of adding drainage plates. The results indicate that during the high-filling process, the overall stability and deformation of the site meet the design control requirements; under the action of large-area high-fill pile load, the vertical and lateral deformations of the foundation soil are mainly concentrated within a depth range of 6.0 meters below the surface; the drainage plate has a significant dissipation effect on the excess pore water pressure, which can effectively reduce the lateral soil pressure and deformation of the foundation, thereby reducing the disturbance effect on the surrounding environment. Compared with the predicted results of theoretical calculation models, the measured deformation of foundation soil is only more significant within a certain depth range. The research results can provide a reference for similar projects.
Temperature and deformation monitoring analysis of rockfill ventilated roadbeds in plateaus freeze-thaw areas
Wang Zhengwei, Wen Liang, Liu Liqiang, Liu Jingquan, Ding Yanming, Huang Weirong, Ren Haisheng
2025, 39(4): 550-557. doi: 10.20265/j.cnki.issn.1007-2993.2024-0036
Abstract:
To clarify the characteristics of uneven settlement and deformation of rockfill ventilated roadbed in plateau freeze-thaw areas, relying on the new highway project of G219 in the Karakorum Mountain area of Xinjiang, the temperature change and settlement deformation of rockfill ventilated roadbed were monitored in real-time by temperature sensors and settlement monitoring. The results show that the rockfill ventilated roadbed hinders the heat transfer from the inside of the road, and with the increase of the filling height, there is an obvious temperature lag at the base of the ventilation roadbed, which reduces the overall settlement deformation of the roadbed and slows down the sunny-shady slope effect.
Cause analysis and comprehensive treatment of the Fengshushan landslide
Wang Xianneng, Wang Qinuo, Shi Yanghai
2025, 39(4): 558-566. doi: 10.20265/j.cnki.issn.1007-2993.2024-0162
Abstract:
The Fengshushan landslide is a traction landslide caused by a cutting slope of engineering construction. Through geological survey, drilling, well exploration, soil test, and comprehensive analysis, the development process of landslide, the basic characteristics of landslide, and the geotechnical characteristics of fault zone were found out, and the stability and deformation trend of landslide were systematically analyzed. Comprehensive treatment measures such as cutting slope and reducing load, setting up the anti-slide pile and anchor cable (anchor rod) frame beam combined support structure, drainage system improvement, and slope greening were put forward. The results show that the geological conditions in the study area are complex, faults are developed and groundwater is abundant in the tectonic belt. The mechanical properties of the silty clay formed from the weathering of the fault structural rock are weak, which are the important conditions for the formation of landslides. Excavation of slope feet and continuous heavy rainfall are the main inducement of landslides. The research results provide a reference for urban geological surveys and similar landslide engineering prevention.
Analytical study on the crack limitation theory of permeable lining of diversion tunnels under high internal pressure
Chen Jie, Wang Yanqiang, Le Ping, Dong Qinuan, Cao Yajun, Wang Wei
2025, 39(4): 567-575. doi: 10.20265/j.cnki.issn.1007-2993.2024-0317
Abstract:
Based on the theory of permeable lining, the design steps of permeable lining were determined, and the calculation formula for solving different crack widths of pressure tunnel lining concrete was given. The reinforcement scheme was obtained by combining with the actual project using the crack width calculation formula in the Chinese and U.S. codes. The results show that: (1) the reinforcing area obtained through the Chinese code is larger than the American code, and the stress of the reinforcement is smaller. (2) The major influencing factors affecting the width of concrete cracks are internal water pressure, reinforcement area, permeability coefficient and the thickness of the lining, which can be adjusted to control the cracking of the concrete by these different influencing factors.
Application of residual pile length detection method in shield or pipe-jacking area
Dong Jiaoshe
2025, 39(4): 576-582. doi: 10.20265/j.cnki.issn.1007-2993.2024-0256
Abstract:
Affected by the complex site conditions and the limitations of geophysical prospecting methods, the applicable detection methods for the length of residual foundation piles are limited within the influence range of shield tunnels or pipe-jacking pipelines in urban areas. Practice and research have proved that for concrete piles (reinforcement), the borehole magnetic gradient method combined with the low-strain elastic wave method is effective; For steel pipe piles or steel sheet piles, the effect of the borehole magnetic gradient method is good. The borehole magnetic gradient method has the characteristics of high precision, fast speed, and strong environmental adaptability. It is easy to damage the underground pipeline by using the conventional drilling method. The drilling technology using a new type of plastic drill bit is proposed, which can better solve the problem of difficult hole formation in the dense area of underground pipeline, and provide references for detecting the pile length of foundation pile by this method.
Excavation method and deformation control of surrounding rock in shallow water diversion tunnels
Xu Jingsuo, Hu Changjian, Shi Wenguang, Xu Zhikang, Hong Hao, Tang Hongquan
2025, 39(4): 583-591. doi: 10.20265/j.cnki.issn.1007-2993.2024-0349
Abstract:
In the coastal area, the excavation of shallow water diversion tunnels in the overlying water-saturated sand layer of strongly weathered rock strata is prone to accidents such as water and sand gushing and surface collapse. To ensure the safe and rapid construction of the tunnel, the optimal method of tunnel excavation and surrounding rock deformation control was provided in the strongly weathered granite stratum of a shallow water diversion tunnel Ⅵ surrounding rock section. Numerical simulation and on-site monitoring methods were used in this project. The results show that: the full section method is less effective in controlling the deformation around the surrounding rock, the CD method is the most effective, and the upper and lower step method and the reserved core soil method are equally effective. Considering that the upper and lower step method has fewer excavation surfaces, lower cost, and shorter construction period, it is taken as the excavation method of this project. Pipe shed and advanced small pipe grouting have the most obvious effect on reducing the settlement of the tunnel vault, and curtain grouting can significantly reduce the deformation of the surrounding rock. Surface curtain grouting supplemented by large pipe shed and advanced small pipe grouting and other combination measures can ensure the safe and rapid construction by using the up-and-down step method for the construction of class Ⅵ surrounding rock section of the shallow water diversion tunnel.
Activity characteristics and cause analysis of Gaoliying ground fissures based on comprehensive geophysical exploration technology
Liu Yan, Ge Zhiguang, Shang Xiaoxu, Lin Zhongwei, Zhang Boyuan, Lu Penglei
2025, 39(4): 592-598. doi: 10.20265/j.cnki.issn.1007-2993.2025-0018
Abstract:
Comprehensive geophysical exploration was conducted on ground fissures in Gaoliying, Shunyi District, Beijing using high-density electrical method and surface wave method. Combined with trenching construction, the development characteristics and causes of the ground fissures were analyzed comprehensively. The research results show that there are anomalies in resistivity and shear wave velocity within 20 meters underground in the area, indicating the presence of ground fissures. After trench exploration verification, it was revealed that the F1 and F2 faults are located on the northwest side of the Gaoliying fault zone, about 4 km away from the main fault zone, consistent with the characteristics of the Gaoliying section of the Huangzhuang-Gaoliying fault. It is inferred that the ground fissures are the latest activity of the Huangzhuang-Gaoliying fault and are a composite type of ground fissures caused by structural and ground subsidence factors.
Experimental Research
Large area construction squeezing effect of PST piles in deep soft soil sites based on CPTU testing
Zheng Jinhuo, Shen Minglong, Jiang Tao, Chen Huahan
2025, 39(4): 599-604. doi: 10.20265/j.cnki.issn.1007-2993.2024-0152
Abstract:
To analyze the soil squeezing effect during the large-scale construction process of PST pipe piles, the multifunctional high-precision pore pressure static penetration test (CPTU) technology was used to test the side wall friction resistance, excess pore water pressure, and dissipation process of the soft soil layer before, during, and after the construction of PST piles. The test results show that in the same layer of silt, the horizontal consolidation coefficient decreases continuously with depth, and the squeezing effect itself also intensifies the decrease in the consolidation coefficient of soft soil. When the pipe piles are longer, the time required to alleviate the squeezing effect is longer; The influence of pile group construction organization on the control of the soil compaction effect is significant, and the pore water pressure increment caused by construction away from the measuring point is only 29% of that caused by construction towards the measuring point; After the construction of PST piles, the strength of the soft soil on the site was reduced by disturbance, with a reduction of up to 40%. After about 120 days, the soil strength of the soft soil layer can recover to the level before construction. For shallow soft soil adjacent to the upper permeable layer, dynamic consolidation occurs after pile driving, and the long-term strength has improved compared to before construction.
Dewatering of high water content subsoil under the action of water absorber
Liu Yong, Wu Hongsheng, Cai Huimin, Li Bin, Wang Xiang, Wang Yuxi
2025, 39(4): 605-610. doi: 10.20265/j.cnki.issn.1007-2993.2024-0263
Abstract:
Most of the high water content subsoil dewatering treatment use methods such as adding flocculants to improve the dewatering performance, and the soil samples cannot be utilized after alkaline agent treatment. For this reason, a physical method of treating high water content subsoil was proposed using polymer water-absorbent resin SAP, and through the indoor water absorption test and mercury intrusion test, the mechanism of dewatering and deformation of high water content subsoil under the action of water-absorbent agent was studied, and the results show that: the water content of subsoil obtained by water-absorbing with polymer water-absorbent resin SAP reached the lowest under the overlaying pressure of 3 kPa. After water absorption, the pore volume and size of the subsoil reduced, and the pore structure became more complex and irregular. Under the action of polymer water-absorbing resin SAP, the free water in the mud was absorbed through the internal permeable channels, the particles were rearranged under the action of self-weight, the permeable channels between the particles were gradually reduced, and the subsoil shrinks and deforms.
Shear characteristics of jute fiber-reinforced sandy soil
Luo Xiaoqin, Li Wenyang, Gao Teng, Yang Kailong, Cheng Yuexin, Guo Hong, Jiang Hong
2025, 39(4): 611-616. doi: 10.20265/j.cnki.issn.1007-2993.2024-0331
Abstract:
To study the reinforcement mechanism and effect of ecological fibers on sandy soil, jute fiber-reinforced sandy soil was taken as the research object. Through a combination of indoor direct shear tests and discrete element numerical simulations, the influence of different jute fiber contents on the shear performance of reinforced sandy soil was analyzed. The research results show that the addition of jute fiber to sand can effectively improve the shear strength of sand. The overall trend is that the cohesion and internal friction angle of sand first increase and then decrease with the increase of fiber content. When the fiber content is 0.4%, the increase in cohesion is the most significant, reaching 20.8 kPa. When the fiber content is 0.2%, the increase in internal friction angle is the largest, with a value of 14.69%. This study provides a reference for the application of ecological fibers in sandy soil filling projects.
Compressive bearing performance of the helical pile embedded in silty clay
Li Zhigang, Li Yang, Wang Xiaofeng, Chai Xiandong, Ren Gang, Chang Honglin, Deng Tianyao
2025, 39(4): 617-623. doi: 10.20265/j.cnki.issn.1007-2993.2024-0127
Abstract:
The helical pile has advantages such as simple structure, convenient construction, and environmental friendliness, and is gradually being applied to the foundation of transmission line towers. Field tests on compressive bearing capacity of helical pile in silty clay foundation were carried out, and the applicability of different determination methods for ultimate bearing capacity was discussed. A three-dimensional model of the helical pile and soil was established using the finite element software ABAQUS. The axial force and lateral frictional resistance of the helical pile, and soil failure mode under vertical compression load were studied. The load sharing ratio of anchor rod and anchor plates under ultimate state was comparatively analyzed through code-based calculation and numerical simulation. The research results show that under vertical compression load, the load-displacement curve of the helical pile exhibits a typical linear-highly nonlinear-approximate linear trend. The lg P-s method and Reese & O’Neill method can be used to assist in determining the ultimate compressive bearing capacity. The upper region of anchor plate exhibits less lateral frictional resistance from the anchor rod, the vertical compression load is mainly resisted through the end resistance of the anchor plate and the lateral friction resistance of the anchor rod between anchor plates. Under ultimate load, soil displacement occurs through three anchor plates to form a relatively complete cylindrical slip surface. The maximum stress and plastic strain of soil under the bottom plate occur first, leading to shear failure. Under ultimate conditions, the load distribution among different parts of the helical pile is as follows: bottom plate > middle plate > top plate > anchor rod. The anchor plates collectively bear around 85% of the load.
Field simulated rainfall erosion test study on embankment bank-grade material
Wang Yantao, Zhang Wenwei, Gao Pingli, Jiao Guomu, Wang Zhanfei, Ma Peilun
2025, 39(4): 624-632. doi: 10.20265/j.cnki.issn.1007-2993.2024-0229
Abstract:
To verify the feasibility of railway embankment slope protection with bank-grade material by erosion test in Middle East region, a field simulated rainfall erosion test device was developed, and a field test method of simulated rainfall erosion on embankment slope was proposed. The reliability of the simulated rainfall device was ensured by quantifying the calibration test parameters. By clarifying the test guidelines, formulating the specific test procedure, and reasonably setting the test items, the erosion resistance of the embankment slope bank-grade material was quantitatively evaluated. By collecting the image data of slope in the process of erosion test, analyzing the development tendency of slope erosion, cross-proving the anti-erosion property of the bank-grade material was carried out to ensure the reliability of the test. Taking a project as an example, the test analysis show that Gatch material has low susceptibility of erosion properties as the embankment bank-grade material.