饱和黏性土静止土压力系数变化规律探讨

Discussion on change rule of earth pressure coefficient at rest of soft saturated clay

采用英国GDS公司生产的应力控制式三轴仪,对珠三角地区的软土进行了K_0固结试验,分析了K_0在加载、卸载过程中的变化规律,总结了K_0随内摩擦角及超固结比的变化特点,并将试验结果与经验公式的计算值进行了对比。得出土体在超固结状态下,加载及卸载阶段K_0系数变化规律相反,前者迅速减小,稳定于正常固结阶段K_0值,后者与超固结比呈幂函数关系逐渐增大接近初始值。文中所测试验数据拟合的n值与有效内摩擦角正弦值呈良好线性关系,且n值与规范建议值极为接近,基于此提出计算n的新公式。

We carried out K0 consolidation tests on the soft soil in the Pearl River Delta area based on the stress-controlled triaxial apparatus which is generated by Britain GDS company, analyzed the transformation law of K0 during the loading and unloading stage, summarized the variation characteristics of K0 with the internal friction and over-consolidation ratio, and compared the experimental results with the calculated values of the empirical formulas. It is concluded that, the change rule of K0 coefficient is opposite when the sample is loaded and unloaded during over-consolidation stage. The former one decreases sharply and become stable in the normally consolidated stage K0 value. The latter one has a power function relationship with the over-consolidation ratio, and gradually increases close to the initial value. The relationship between fitting value of n basing on experimental data and sine value of effective angle of internal friction is linearity, and the value of n is very close to suggestive value of standard. Then the new formula for calculating n is proposed.