The stability of soil-rock mixtures(SRMs) that widely distributed in slopes is of significant concern for slope safety evaluation and disaster prevention. The failure behavior of SRM slopes under surface loading condi...The stability of soil-rock mixtures(SRMs) that widely distributed in slopes is of significant concern for slope safety evaluation and disaster prevention. The failure behavior of SRM slopes under surface loading conditions was investigated through a series of centrifuge model tests considering various volumetric gravel contents. The displacement field of the slope was determined with image-based displacement system to observe the deformation of the soil and the movement of the block during loading in the tests. The test results showed that the ultimate bearing capacity and the stiffness of SRM slopes increased evidently when the volumetric block content exceeded a threshold value. Moreover, there were more evident slips around the blocks in the SRM slope. The microscopic analysis of the block motion showed that the rotation of the blocks could aggravate the deformation localization to facilitate the development of the slip surface. The high correlation between the rotation of the key blocks and the slope failure indicated that the blocks became the dominant load-bearing medium that influenced the slope failure. The blocks in the sliding body formed a chain to bear the load and change the displacement distribution of the adjacent matrix sand through the block rotation.展开更多
Centrifugal model testsare playing an increasingly importantrolein investigating slope characteristics under rainfall conditions. However, conventional electronic transducers usually fail during centrifugal model test...Centrifugal model testsare playing an increasingly importantrolein investigating slope characteristics under rainfall conditions. However, conventional electronic transducers usually fail during centrifugal model tests because of the impacts of limitedtest space, high centrifugal force, and presence of water, with the result that limited valid data is obtained. In this study, Fiber Bragg Grating(FBG) sensing technology is employed in the design and development of displacement gauge, an anchor force gauge and an anti-slide pile moment gauge for use on centrifugal model slopes with and without a retaining structure. The two model slopes were installed and monitored at a centrifugal acceleration of 100 g. The test results show that the sensors developed succeed in capturing the deformation and retaining structure mechanical response of the model slopes during and after rainfall. The deformation curvefor the slope without retaining structure shows a steepresponse that turns gradualfor the slope with retaining structure. Importantly, for the slope with the retaining structure, results suggest that more attention be paid to increase of anchor force and antislide pile moment during rainfall. This study verifies the effectiveness of FBG sensing technology in centrifuge research and presents a new and innovative method for slope model testing under rainfall conditions.展开更多
This paper introduces model test results of water pressure in a fault, which is located in a slope and 16 different conditions. The results show that the water pressures in fault can be expressed by a linear function,...This paper introduces model test results of water pressure in a fault, which is located in a slope and 16 different conditions. The results show that the water pressures in fault can be expressed by a linear function, which is similar to the theoretical model suggested by Hoek. Factors affecting water pressures are water level in tension crack, dip angle of fault, the height of filling materials and thickness of fault zone in sequence.展开更多
When transparent soil technology is used to study the displacement of a slope, the internal deformation of the slope can be visualized. We studied the sliding mechanism of the soil-rock slope by using transparent soil...When transparent soil technology is used to study the displacement of a slope, the internal deformation of the slope can be visualized. We studied the sliding mechanism of the soil-rock slope by using transparent soil technology and considering the influence of the rock mass Barton joint roughness coefficient, angle of the soil mass, angle of the rock mass and soil thickness factors on slope stability. We obtained the deformation characteristics of the soil and rock slope with particle image velocimetry and the laser speckle technique. The test analysis shows that the slope sliding can be divided into three parts: displacements at the top, the middle, and the bottom of the slope; the decrease in the rock mass Barton joint roughness coefficient, and the increase in soil thickness, angles of the rock mass and soil mass lead to larger sliding displacements. Furthermore, we analyzed the different angles between the rock mass and soil thickness. The test result shows that the displacement of slope increases with larger angle of the rock mass. Conclusively, all these results can help to explain the soil-rock interfacial sliding mechanism.展开更多
Stability of an ancient landslide in a reservoir area is analyzed by using centrifugal model tests, soil laboratory tests and numerical analysis. Special attention is paid to variation in water level, simulation of la...Stability of an ancient landslide in a reservoir area is analyzed by using centrifugal model tests, soil laboratory tests and numerical analysis. Special attention is paid to variation in water level, simulation of large-scale heterogeneous prototype slope, and strength reduction of sliding zone soils after slope sliding. The results of centrifugal model test show that reservoir impounding can reduce sliding resistance at the slope toe, followed by toe collapsing and front cracking of slope. Rapid drawdown can produce hydrodynamic pressure towards reservoir at the front of slope. Deformation is observed in the middle and upper slope, which reduces the slope stability further and forms the pull-typed landslide trend. Reinforcement of slope toe is effective for preventing the progressive failure. The results of laboratory test show that slope toe sliding will lead to the redistribution of soil density and moisture content, which will reduce the shear strength of soil in sliding zone, and the cohesion of immersed soil is reduced gradually and finally vanishes with time. The numerical results show that the strength reduction method used in finite element method (FEM) is very effective in capturing the progressive failure induced by reservoir water level fluctuations, and the evolution of failure surface derived from numerical simulation is very similar to that observed in centrifugal model test.展开更多
Surface wave generation due to body wave propagation near ground surface has been discussed in the literature.This phenomenon,typically occurring in topographic changing areas,along with its interaction with body wave...Surface wave generation due to body wave propagation near ground surface has been discussed in the literature.This phenomenon,typically occurring in topographic changing areas,along with its interaction with body waves(SV),decreases precision of formulas for evaluation of slope displacement.This signi fi cant fact caused the researchers not only to investigate the combined surface and SV waves motion pattern,but also to consider its effect on structures built on the slopes.In order to reveal the phenomenon,several fi nite element numerical studies have been performed by ABAQUS programme.Besides,two physical model slopes simulating the landslide occurrence have been constructed and tested by shaking table device.The results of induced and calculated accelerations obtained by two approaches have been compared and Rayleigh wave generation has been proved.Furthermore,the slope displacements have been calculated by various empirical methods and the results were compared with numerical ones.The results proved that in order to increase the precision of empirical formulas for displacement prediction,surface wave effect should be taken into account.Finally,a concept of'effective depth of sur fi cial ampli fi cation'is introduced and its effect on dynamic slope stability is analysed.展开更多
基金supported by National Key R&D Program of China(2018YFC1508503)
文摘The stability of soil-rock mixtures(SRMs) that widely distributed in slopes is of significant concern for slope safety evaluation and disaster prevention. The failure behavior of SRM slopes under surface loading conditions was investigated through a series of centrifuge model tests considering various volumetric gravel contents. The displacement field of the slope was determined with image-based displacement system to observe the deformation of the soil and the movement of the block during loading in the tests. The test results showed that the ultimate bearing capacity and the stiffness of SRM slopes increased evidently when the volumetric block content exceeded a threshold value. Moreover, there were more evident slips around the blocks in the SRM slope. The microscopic analysis of the block motion showed that the rotation of the blocks could aggravate the deformation localization to facilitate the development of the slip surface. The high correlation between the rotation of the key blocks and the slope failure indicated that the blocks became the dominant load-bearing medium that influenced the slope failure. The blocks in the sliding body formed a chain to bear the load and change the displacement distribution of the adjacent matrix sand through the block rotation.
基金supported by the National Natural Science Foundation of China (Grant Nos.41502299,41372306)Research Planning of Sichuan Education Department, China (Grant No.16ZB0105)State Key Laboratory of Geohazard Prevention and Geoenvironment Protection Independent Research Project (SKLGP2016Z007)
文摘Centrifugal model testsare playing an increasingly importantrolein investigating slope characteristics under rainfall conditions. However, conventional electronic transducers usually fail during centrifugal model tests because of the impacts of limitedtest space, high centrifugal force, and presence of water, with the result that limited valid data is obtained. In this study, Fiber Bragg Grating(FBG) sensing technology is employed in the design and development of displacement gauge, an anchor force gauge and an anti-slide pile moment gauge for use on centrifugal model slopes with and without a retaining structure. The two model slopes were installed and monitored at a centrifugal acceleration of 100 g. The test results show that the sensors developed succeed in capturing the deformation and retaining structure mechanical response of the model slopes during and after rainfall. The deformation curvefor the slope without retaining structure shows a steepresponse that turns gradualfor the slope with retaining structure. Importantly, for the slope with the retaining structure, results suggest that more attention be paid to increase of anchor force and antislide pile moment during rainfall. This study verifies the effectiveness of FBG sensing technology in centrifuge research and presents a new and innovative method for slope model testing under rainfall conditions.
基金This paper is supported by the Research Fund for the Doctoral Program of Higher Education of China.
文摘This paper introduces model test results of water pressure in a fault, which is located in a slope and 16 different conditions. The results show that the water pressures in fault can be expressed by a linear function, which is similar to the theoretical model suggested by Hoek. Factors affecting water pressures are water level in tension crack, dip angle of fault, the height of filling materials and thickness of fault zone in sequence.
基金funded by the Scholarship for Visiting Scholars of the Key Laboratory of New Technology for Construction of Cities in Mountain Areas, Chongqing University (Grant No. 0902071812102/011)the Major Project of the Provincial Science Foundation of Inner Mongolia, China (Grant No. 2012ZD0602)+1 种基金Ordos UEGE, China (Grant No. 18-8)the National Natural Science Foundation of China (Grant No. 51622803)
文摘When transparent soil technology is used to study the displacement of a slope, the internal deformation of the slope can be visualized. We studied the sliding mechanism of the soil-rock slope by using transparent soil technology and considering the influence of the rock mass Barton joint roughness coefficient, angle of the soil mass, angle of the rock mass and soil thickness factors on slope stability. We obtained the deformation characteristics of the soil and rock slope with particle image velocimetry and the laser speckle technique. The test analysis shows that the slope sliding can be divided into three parts: displacements at the top, the middle, and the bottom of the slope; the decrease in the rock mass Barton joint roughness coefficient, and the increase in soil thickness, angles of the rock mass and soil mass lead to larger sliding displacements. Furthermore, we analyzed the different angles between the rock mass and soil thickness. The test result shows that the displacement of slope increases with larger angle of the rock mass. Conclusively, all these results can help to explain the soil-rock interfacial sliding mechanism.
基金Supported by the National Natural Science Foundation of China (11072088)Guangdong Provincial Water Resources Science and Technology Project (ysk2009-01)
文摘Stability of an ancient landslide in a reservoir area is analyzed by using centrifugal model tests, soil laboratory tests and numerical analysis. Special attention is paid to variation in water level, simulation of large-scale heterogeneous prototype slope, and strength reduction of sliding zone soils after slope sliding. The results of centrifugal model test show that reservoir impounding can reduce sliding resistance at the slope toe, followed by toe collapsing and front cracking of slope. Rapid drawdown can produce hydrodynamic pressure towards reservoir at the front of slope. Deformation is observed in the middle and upper slope, which reduces the slope stability further and forms the pull-typed landslide trend. Reinforcement of slope toe is effective for preventing the progressive failure. The results of laboratory test show that slope toe sliding will lead to the redistribution of soil density and moisture content, which will reduce the shear strength of soil in sliding zone, and the cohesion of immersed soil is reduced gradually and finally vanishes with time. The numerical results show that the strength reduction method used in finite element method (FEM) is very effective in capturing the progressive failure induced by reservoir water level fluctuations, and the evolution of failure surface derived from numerical simulation is very similar to that observed in centrifugal model test.
文摘Surface wave generation due to body wave propagation near ground surface has been discussed in the literature.This phenomenon,typically occurring in topographic changing areas,along with its interaction with body waves(SV),decreases precision of formulas for evaluation of slope displacement.This signi fi cant fact caused the researchers not only to investigate the combined surface and SV waves motion pattern,but also to consider its effect on structures built on the slopes.In order to reveal the phenomenon,several fi nite element numerical studies have been performed by ABAQUS programme.Besides,two physical model slopes simulating the landslide occurrence have been constructed and tested by shaking table device.The results of induced and calculated accelerations obtained by two approaches have been compared and Rayleigh wave generation has been proved.Furthermore,the slope displacements have been calculated by various empirical methods and the results were compared with numerical ones.The results proved that in order to increase the precision of empirical formulas for displacement prediction,surface wave effect should be taken into account.Finally,a concept of'effective depth of sur fi cial ampli fi cation'is introduced and its effect on dynamic slope stability is analysed.