关键词: 单剪, 莫尔圆, 主应力, 主应力轴方向, 影响因素

Abstract:

The changing process of stress Mohr circle in simple shear is analyzed in detail. In the analysis, the process is regard as a components of some incremental step in equal; and two variables are difined: one is the difference between two minor principal stresses corresponding to a random shear stress state and the initial state, another is the difference between two major principal stresses corresponding to a random shear stress state and the initial state; Then the ratio value of the two variables is proved to be constant, which can be got by the Mohr circle in initial state and failure state. Furthermore, expressions of the principal stresses and the corresponding axis directions related to a random shear stress in simple shear are deduced. The influence of soil character parameters and normal stress on the principal stress axis directions is discussed. The relationship between principal stress and shear stress is also evaluated. Studying shows that under the same soil character parameters, the direction of principal stress axis are only decided by the stress ratio; for constant normal stress and shear stress, the rotation angle of principal stress axis increases with the decrement of internal friction angle of the soil, the principal stresses change slowly at the beginning of shearing, change sharply with the increament of shear stress, and keep constant in the failure state.

Key words: simple shear, Mohr circle, principal stress, principal stress axis direction, influence factor