土石混合体介质具有高度非均质性、显著的结构效应与尺寸效应等特点,这使其物理力学特性及其复杂。本文针对土石混合体在剪切过程中剪切带的变形性状与影响因素,采用自主研发的RSM–1000型电机伺服控制大型土工抗剪强度试验系统,考虑不...土石混合体介质具有高度非均质性、显著的结构效应与尺寸效应等特点,这使其物理力学特性及其复杂。本文针对土石混合体在剪切过程中剪切带的变形性状与影响因素,采用自主研发的RSM–1000型电机伺服控制大型土工抗剪强度试验系统,考虑不同含石量(0,30%,50%,70%)、上覆压力(50,200,300,400 k Pa)、块石尺寸(L1,L2,L3)3个主要结构控制因素,进行土石混合体剪切变形试验,通过在试样内部钻孔设置铝丝与干灰的方法,监测剪切带特征变化规律。研究结果表明:当含石量小于30%时,块石对试样的变形影响较小,强度主要依赖于砂土强度;当含石量达到50%时,试样内已形成骨架结构,变形受块石的影响突显,强度由块石和砂土共同作用;当含石量达到70%时,试样内已形成块石架空结构。在高含石量与大粒径块石条件下,含贯穿剪切面的块石试样随剪切变形发展,块石发生挤压、翻转现象;剪切面附近分布块石的试样,随剪切变形发展,块石以剪胀作用为主,块石发生挤压、棱角剪断与错动重分布。试样的剪切变形现象可类比由后向前变形的推移式滑坡或由前后向中间变形的复合式滑坡的破坏特征,即后缘坡顶在主动土压力作用下产生裂隙,随之下沉挤密、失稳起滑;前缘坡脚蠕滑变形推移;坡中岩土体发生剪切错动至滑动面渐进扩展破坏,最终剪切面贯通,形成整体破坏。该研究成果对揭示土石混合体滑坡剪切带形成演化规律、破坏模式及土石混合体滑坡的防灾减灾具有重要意义。展开更多
The past decade has been characterized by the development of infrastructure in the main cities in West Africa.This requires more comprehensive studies of geotechnical properties of the soil in the region with an aim o...The past decade has been characterized by the development of infrastructure in the main cities in West Africa.This requires more comprehensive studies of geotechnical properties of the soil in the region with an aim of creating sustainable development.This paper examined the performance of the soil in Benin(West Africa).In this research,three objectives have been adopted in-depth on the performance characteristics of West Africans soil and aim to(i)accessing characteristics of soil types in the region;(ii)assessing the performance of these soils with 2%,3%and 5%of lime and(iii)characterizing landslide to evaluate the damage and potential instability.The methods used to examine these objectives are experimental tests according to standard French test.The particle size test,Proctor test,and Atterberg limits test which are physical tests and the mechanical tests such as dynamic penetration test,direct shear test,and oedometer test,were used to assess the first objective.The Proctor test and California bearing ratio test were examined for the second objective and geological,environmental,social and safety study of the river bank slide were evaluated for the third objective.This paper firstly reveals the unstable and stable areas in southern Benin(West Africa)with the presence of clays soil and gives an equation for predicting the unstable and stable area,and secondly shows that the proportion of percentage lime leading to the best performances varying between 2%and 3%.Finally,this paper shows that the sliding of a bank could be the consequence of the sudden receding water recorded in a valley.展开更多
文摘土石混合体介质具有高度非均质性、显著的结构效应与尺寸效应等特点,这使其物理力学特性及其复杂。本文针对土石混合体在剪切过程中剪切带的变形性状与影响因素,采用自主研发的RSM–1000型电机伺服控制大型土工抗剪强度试验系统,考虑不同含石量(0,30%,50%,70%)、上覆压力(50,200,300,400 k Pa)、块石尺寸(L1,L2,L3)3个主要结构控制因素,进行土石混合体剪切变形试验,通过在试样内部钻孔设置铝丝与干灰的方法,监测剪切带特征变化规律。研究结果表明:当含石量小于30%时,块石对试样的变形影响较小,强度主要依赖于砂土强度;当含石量达到50%时,试样内已形成骨架结构,变形受块石的影响突显,强度由块石和砂土共同作用;当含石量达到70%时,试样内已形成块石架空结构。在高含石量与大粒径块石条件下,含贯穿剪切面的块石试样随剪切变形发展,块石发生挤压、翻转现象;剪切面附近分布块石的试样,随剪切变形发展,块石以剪胀作用为主,块石发生挤压、棱角剪断与错动重分布。试样的剪切变形现象可类比由后向前变形的推移式滑坡或由前后向中间变形的复合式滑坡的破坏特征,即后缘坡顶在主动土压力作用下产生裂隙,随之下沉挤密、失稳起滑;前缘坡脚蠕滑变形推移;坡中岩土体发生剪切错动至滑动面渐进扩展破坏,最终剪切面贯通,形成整体破坏。该研究成果对揭示土石混合体滑坡剪切带形成演化规律、破坏模式及土石混合体滑坡的防灾减灾具有重要意义。
基金Project(41627801)supported by the National Major Scientific Instruments Development Project of ChinaProject(41430634)supported by the State Key Program of National Natural Science Foundation of China+1 种基金Project(2016YJ004)supported by the Opening Fund for Innovation Platform of ChinaProject(2016G002-F)supported by the Technology Research and Development Plan Program of China Railway Corporation
文摘The past decade has been characterized by the development of infrastructure in the main cities in West Africa.This requires more comprehensive studies of geotechnical properties of the soil in the region with an aim of creating sustainable development.This paper examined the performance of the soil in Benin(West Africa).In this research,three objectives have been adopted in-depth on the performance characteristics of West Africans soil and aim to(i)accessing characteristics of soil types in the region;(ii)assessing the performance of these soils with 2%,3%and 5%of lime and(iii)characterizing landslide to evaluate the damage and potential instability.The methods used to examine these objectives are experimental tests according to standard French test.The particle size test,Proctor test,and Atterberg limits test which are physical tests and the mechanical tests such as dynamic penetration test,direct shear test,and oedometer test,were used to assess the first objective.The Proctor test and California bearing ratio test were examined for the second objective and geological,environmental,social and safety study of the river bank slide were evaluated for the third objective.This paper firstly reveals the unstable and stable areas in southern Benin(West Africa)with the presence of clays soil and gives an equation for predicting the unstable and stable area,and secondly shows that the proportion of percentage lime leading to the best performances varying between 2%and 3%.Finally,this paper shows that the sliding of a bank could be the consequence of the sudden receding water recorded in a valley.
