含水率对非饱和压实土抗剪强度影响试验研究

Experimental Study on Influence of Moisture Content on the Shear Strength of Unsaturated Compacted Soil

对压实土进行不同含水率直剪试验,得到其抗剪强度;利用接触滤纸法测量土基质吸力,得到其土水特征曲线;基于吸引力强度理论,探讨了在最优含水率附近的重塑土的基质吸力、黏聚力与含水率的关系。研究表明:基质吸力与含水率的关系曲线呈内凹双曲线形态,与含水率关系是单调递减的;黏聚力与含水率的关系曲线呈抛物线型,且在最优含水率处最大;转化率随基质吸力的增加而逐渐降低,高基质吸力下土体含水率偏低,基质吸力难以有效转化为吸应力,故而黏聚力偏小。

The shear strength of the compacted soil is obtained by direct shear experiments with different moisture content;the soil matrix suction is measured by the contact filter paper method,and the SWCC of the compacted soil is obtained;and the relationship between the matrix suction,cohesion and water content of the remolded soil near the optimal water content is studied based on the strength of attraction theory.The research results show that the matrix suction and moisture content curve is in the form of concave hyperbola,and the relationship with moisture content curve is a monotonous decreasing curve,the relationship between cohesion and moisture content is approximately parabolic,and the optimal moisture content corresponds to the cohesive force of the matrix is the largest;the conversion rate of matrix suction into suction stress gradually decreases with the increase of matrix suction.The soil moisture content in the high suction section is low,and the matrix suction is difficult to effectively transform into suction stress,leading to small cohesion.