不同饱和度的高边坡黏土抗剪强度分析

Analysis of Shear strength of High Slope Clay with different Water saturation

采用直剪仪对不同饱和度下的高边坡重塑黏土在不同固结压力下进行固结不排水试验。结果表明,含水量对重塑黏土的抗剪强度有很大影响。较低垂直压力会使得试样孔隙水压力在短期固结过程中消散不完全,使有效应力处于较低的水平,致使硬化及软化现象明显,在饱和度大于80.23%后,试样粘聚力明显减小。在受外力作用下,随着饱和度的增加,土样小孔隙的水会流入大孔隙中。因此,在降雨过后,不应在坡面堆载。当雨水渗入量接近土的塑限值时应尤为注意,进行高边坡稳定性分析时,充分结合含水量对土壤抗剪强度的影响,按最不利情况分析。工程应结合地区降雨情况,时做好排水措施,避免雨水的过多入渗。

In this paper,the consolidated undrained tests of the remolded clay samples of a high slope under different water content were performed under different consolidation pressures(50,100,200 and 400 kPa).The results show that the water content has a significant influence on the shear strength of the remolded clay.The lower vertical pressure will make the pore water pressure in the sample dissipate incompletely in the short-term consolidation process,resulting in a lower effective stress,resulting in obvious hardening or softening.When the degree of saturation is more than 80.23%,the cohesion of the sample decreases obviously.In addition,combined with nuclear magnetic resonance analyzer,the pore water distribution in soil samples with different degrees of saturation is analyzed.It is proved that the water in the small pores will flow into macropores under external load,which provides evidence for the sudden decrease of cohesion in the direct shear test.