含水量对顺层坡风化界面剪切特性试验研究

Experimental Study on Shear Properties of Water Content for Bedding Slope Weathered Interface

顺层坡风化界面常为顺层坡破坏的潜在滑动面。为指导边坡防护设计,利用直剪试验探究含水量对顺层坡风化界面剪切特性的影响。结果表明:风化界面的剪切存在剪切软化特征,应力越大,风化界面的应变软化的特征越明显。风化界面以13.2%含水量为界,黏聚力和内摩擦角先增大后降低,25.4%的含水量时,风化界面剪切过程中存在流态特征。设计人员应设计措施使土体含水量保持在最优含水量,增强边坡自身稳定性;另一方面,设计防护支挡应充分考虑土体黏聚力和内摩擦角随含水量增大而表现出的参数弱化,使边坡在界面参数弱化后依然保持稳定不滑塌。

The weathered interface of bedding slope is the potential dangerous sliding failure usually. To guide the protection designing of the slope,the shear properties characteristics of bedding slope weathered interface in different water content have been conducted in direct shear tests. It shows that the failure of weathering interface performs the characteristic of shearing strain-softening,the greater the stress,the more obvious the strain softening characteristics. The water content of 13. 2% plays a dividing role during these tests,the cohesion and internal friction angle increases when the water content is smaller than 13. 2%,and decreases when the water content is bigger than 13. 2%. The failure of weathering interface performs the fluid characteristic when the water content is 25. 4%. The significances of these tests for designers are that some measures should be designed to maintain the weathered interface at the optimum water content to strength the stability of the bedding slope. On the other hand,the weakening of cohesion and internal friction angle increases should be taken full account to design the protection retaining,so that the bedding slope would keep stable even the weathered interface parameters are weakling.