基于一种新强度理论的非饱和土边坡稳定性分析

非饱和土强度及其边坡稳定性一直是工程界和理论界的一个重要课题.Bishop和Fredlund提出的抗剪强度公式虽被广泛接受,但应用工程仍存诸多不便.针对于此,作者提出了一种有效应力与土水特征曲线发展成的一种新的非饱和土强度公式.该公式不需多组的非饱和土剪切试验,便于工程应用.基于此强度公式,采用VB语言,结合Bishop法,编写了非饱和土边坡稳定性的计算程序,讨论了强度分层的影响,还分析了裂隙对非饱和土边坡稳定性的影响.研究结果表明,对于膨胀土边坡,强度的分层是合理的,也是必要的.

Study on shear strength of the unsaturated soil and slope stability analysis

Shear strength and slope stability of unsaturated soils are always important problems.Shear strength expresses put forward by Bishop and Fredlund have widely been accepted.However,due to the parameters,the equations have some difficulties in applying to engineering.In view of that,a kind of effective stress and soil-water characteristic curve have been used to develop a new shear strength.The shear strength is advantageous to engineering owing to not requiring many triaxial tests of unsaturated soils.On the basis of the formula,the paper utilizes Bishop's simplified method to develop the computing program for calculating the safety factor of unsaturated soil slopes by Visual Basic.The effect of shear strength stratification on the slope stability is discussed.The paper also analyzes effects of cracks and fissures on the safety factor of unsaturated soil slopes.The researches point out that stratification of shear strength is rational and indispensable for expansive soil slopes.