残积土及全风化层土原位水平推剪试验研究

The Research of In-situ Horizontal Push-shear Test of Residual Soil and Completely Weathering Layer

水平推剪试验是测定土的抗剪强度指标的大型原位试验,以厄瓜多尔德尔西水电站工程区广泛分布的残积土及全风化层土为研究对象,通过开展大型原位水平推剪试验,取得该类土石混合体的抗剪强度参数c、φ值,并对其变形破坏特征进行研究。试验结果表明,土石混合体的抗剪强度指标与其含石率、材料强度、结构联接强度均有一定程度的关系,其力学特性介于土体和岩体之间,试验后推剪应力—应变曲线有明显的阶段性,能反映土石混合体的变形特征。相比于室内试验,在原位进行水平推剪试验取得的成果更能代表残积土及全风化片麻岩的抗剪强度特性。

The horizontal push-shear test is a large in-situ test to measure the shear strength index of soil. This article used the residual soil and completely weathering layer that widely distributed in Ecuador Delsi hydropower station as the research object,through conducting large in-situ horizontal push-shear test,the shear strength parameters c,φvalue of rock-soil aggregate can be obtained,and deformation and failure characteristics of it are studied. The test shows that there is a certain degree of relationship between the shear strength parameters of rock-soil aggregate and its stone content,material strength,structural connection strength,the mechanical properties between soil mass and rock mass,the pushing shear stress-strain curve shows obvious periodicity,can reflect the characteristics of deformation of rock-soil aggregate. Compared with the indoor experiment,the result of in-situ horizontal push-shear test can better represent the shear strength properties of residual soil and completely weathered gneiss.