压实填土一般为典型的非饱和土,广泛存在于各类工程中,其物理力学性质受填土含水状态的影响。因基质吸力测量困难,非饱和土强度理论难以在压实填土工程中应用。研究含水状态变化对压实土抗剪强度影响的大小,寻找一种简化实用的非饱和压实土抗剪强度确定方法。从非饱和土理论出发,对含水状态影响压实土抗剪强度的机制进行了分析,重新整理并分析了5种压实土的非饱和三轴试验结果,对一些压实土工程资料中的直剪试验强度指标进行了收集和整理。分析表明,基质吸力对压实填土抗剪强度的贡献占有相当大的比例;含水率变化对压实填土抗剪强度的影响是非常显著和不容忽视的。工程资料中压实土饱和度对数值与黏聚力指标有良好的线性相关关系,提出了一个考虑饱和度影响的压实填土抗剪强度简易计算方法。
Compacted soil,which widely exists in many sorts of engineering projects,is commonly unsaturated soil;and its physico-mechanical characteristics are influenced by soil moisture.Because of the difficulty in matric suction measurement,it is hard to apply the unsaturated soil strength theory to compacted soil projects.This paper aims to research how much influence on shear strength of compacted soil when soil moisture varies,and tries to find an easy and useful way in determining the shear strength of unsaturated compacted soils.Research works start from the theory of unsaturated soil,and the mechanism,with which soil moisture affects shear strength of compacted soil,is analyzed.Triaxial shear test results of five sorts of unsaturated compacted soils are rearranged and analyzed;and strength parameters of direct shear test are collected and arranged from data of some filled and compacted soil projects.Analysis shows that matric suction contributes a considerable portion of shear strength in the compacted soils;and the influence of soil moisture on shear strength of compacted soil is obvious and can not be neglected.A fine linear relationship between logarithmic saturation and cohesion of compacted soil is found in project data;and a simple method for calculating shear strength of compacted soil,which can take saturation degree influence into account,is presented.