低液限粉质黏土最大主应力差与含水率关系特征研究

粉质黏土天然孔隙比大，压缩性高，盾构施工中，经常会遇到粘附刀盘和地表沉降过大等问题。研究粉质黏土最大主应力差与含水率的关系，对减小刀盘粘附和控制地表沉降具有重要的意义。试验研究了应力水平和应力路径对主应力差关系特征的影响，获得了不同围压条件下土的抗剪强度的变化规律。结果表明:土样破坏特征为明显的鼓型破坏；粉质黏土对于含水率的变化非常敏感，2%含水率的变化都会使粉质黏土的强度发生明显改变；拟合出可用于估算一般低液限粉质黏土最大主应力差的经验公式。

Study on the Relationship between the Maximum Main Stress Difference and Water Content in Low Liquid Limit Silty Clay

The silty clay has large natural void ratio and high compressibility. During the construction of the shield, silt clay often encounters such problems as adhering cutterhead and excessive settlement after construction. Therefore, it is significant to study the characteristics of the main stress difference of silty clay under different water content conditions. The influence of stress level and stress path on the characteristics of the principal stress difference was analyzed. The variation of shear strength under different confining pressures was compared. The results show that the damage characteristics of soil samples are obvious drum damage and no shear cracks appear. The stress-strain curve of silty clay can be divided into elastic-plastic phase and stress-relaxation phase. Silty clay is very sensitive to the change of water content. The change of 2% water content will change the strength of silty clay obviously. Through experiments, the empirical formula that can estimate the maximum principal stress difference of general low liquid limit silty clay can be fitted.