干密度对定向剪切下重塑黄土力学特性影响研究

Effect of dry density on mechanical properties of remolded loess under directional shear stress path

为研究不同干密度对定向剪切下重塑黄土力学特性的影响,采用英国GDS空心圆柱扭剪仪(HCA)对青海重塑黄土进行一系列定向剪切试验。试验保持平均主应力、中主应力系数和大主应力方向角不变,重点探讨干密度的变化对定向剪切条件下重塑黄土强度和变形的影响。试验结果表明:重塑黄土在定向剪切路径下破坏强度随着干密度的增大而增大;重塑黄土的八面体剪应变和主应变的开展模式受到初始干密度的显著影响;重塑黄土的归一化强度随干密度的增大呈现出近似线性增长的趋势;重塑黄土在剪切破坏后期的大主应力方向和应变方向不一致,存在明显的非共轴现象;在干密度为1.72 g/cm^(3)时,重塑黄土剪切破坏时的非共轴角超过12°。

To investigate how different dry densities affect the mechanical properties of remolded loess under directional shear stress,a series of tests were carried out using a GDS hollow cylinder torsional shear apparatus on Qinghai remolded loess.The focus was on understanding how changes in dry density affect the strength and deformation of remolded loess when the average principal stress,intermediate principal stress coefficient,and principal stress direction angle remain constant.The results show that the failure strength of remolded loess increases as dry density increases under the directional shear stress.Furthermore,the initial dry density significantly affects the development patterns of octahedral shear strain and principal strain.The normalized strength of remolded loess shows an approximately linear increase with higher dry densities.During the later stages of shear failure,the principal stress direction and strain of remolded loess become inconsistent,showing an obvious non-coaxial phenomenon.Notably,at a dry density of 1.72 g/cm^(3),the non-coaxial angle at shear failure exceeds 12°.