主应力方向和中主应力系数对冻结黏土性状的影响

摘要

To study mechanical properties of frozen saturated clay(FSC)under complex stress path, a series of directional shear tests were conducted using dynamic hollow cylinder testing apparatus of frozen soils(FHCA-300). Impacts of major principal stress direction and coefficient of intermediate principal stress on the stress-strain property of FSC were investigated through the directional shear tests. The results indicate that the stress-strain curves of FSC all perform as strain hardening under directional shearing, and the torsional shear component dominates the generalized shear stress-strain curves. Under different major principal stress directions, stress-strain curves of FSC have different levels correspondingly.When the coefficient of intermediate principal stress is 0.5 or 1, the level of generalized shear stress-strain curves will decrease with increase of the direction angle of major principal stress. The coefficient of intermediate principal stress has slight influence on the stress-strain property of torsional shear component,but has great influence on axial component and generalized stress-strain property.%为研究复杂应力路径下冻土的力学特性,利用冻土空心圆柱仪对饱和冻结黏土开展了定向剪切试验,重点研究了大主应力方向和中主应力系数对饱和冻结黏土应力应变性状的影响.试验结果表明:定向剪切路径下饱和冻结黏土应力-应变曲线基本呈现应变硬化特征,且广义剪应力-应变曲线受扭剪分量的主导.不同大主应力方向下冻结黏土应力-应变曲线水平存在一定差异,当中主应力系数b为0.5和1时广义剪应力-应变曲线水平随着大主应力方向角α的增加而降低.中主应力系数b对冻结黏土扭剪分量的应力应变性状影响相对较小,而对轴向分量与广义剪应力应变性状影响显著.