原状黄土割线模量变化规律试验研究

Experimental research on variation laws of secant modulus of original loess

土体的变形与强度一直是岩土力学领域的两大主题,土体破坏的宏观表现就是变形。因此,在外荷载等因素作用下,土体的变形特点与过程也可以从宏观上反映土体强度变化的本质。基于对陕西杨凌原状Q3黄土进行不同剪切速率下的三轴固结不排水剪切试验研究,发现其割线模量随应变的增大而呈幂函数减小。在临界剪切速率的前后,割线模量随应变的增大而减小的幅度变小。在同一初始含水率下,围压越大,弹性模量值也越大;初始含水率越大,不同围压下的割线模量随轴向应变的变化曲线越稀疏。高含水率下的曲线变化趋势比低含水率下的曲线变化趋势要平缓。

Deformation and strength of soil have always been the two main themes in the geotechnical research,and the destruction is shown by the soil macro-deformation.Therefore,under the influence of external factors such as load,the characteristics and process of soil deformation can also reflect the nature of soil strength variation.Based on consolidated undrained triaxial shear test on the original Q3 loess in Yangling area of Shaanxi Province under different shear rates,it is found that secant modulus decreases with the strain increasing in the manner of power function.Before and after the critical shear rate,the decreasing amplitude of secant modulus with strain increasing tends to decrease;under the same initial moisture content,the greater the confining pressure is,the greater the elastic modulus value is;the greater the initial moisture content is,the more sparse the curves of secant modulus and axial strain under different confining pressure are.The variation trend of the curve is gentler under high moisture content than that under low moisture content.