不同含水量顺层坡风化界面剩余下滑力研究及工程防护意义

研究了含水量对顺层坡风化界面剩余下滑力的影响。以贵州高速公路某段顺层坡填方路基为背景,将室内试验与剩余下滑力计算结合进行研究。结果表明:黏聚力在最优含水量附近存在着极大值。黏聚力c随含水量增大先增大后减小。内摩擦角φ在最优含水量附近时也有极大值,呈现同样的规律先增大后降低。随着含水量增加,下滑段先变短后增长,抗滑段先增长后变短。最优含水量时,桩板墙所承受的剩余下滑力最小。分析认为含水量的增大一方面加速了顺层坡泥质成分的软化,加速了层面的破坏。另一方面降低了风化界面的力学参数,抗剪强度降低,剩余下滑力增大。因此,对于该段路基边坡设计而言,应在左幅坡体挖盲沟进行排水,减少流入路基的地下水;同时防治排水沟渗漏水进入路基;路基内部应设置盲沟,降低地下水的长期集聚对风化面的侵蚀软化。

Investigation on Residual thrust of Bedding Slope Weathered Interfaceof Different Water Content and Significance for Engineering Protection

To investigate the influence of water content for residual thrust of bedding slope weathered interface. The roadbed slope in Guizhou highway has been cited as the geology background, shear tests and analysis of residual thrust has been combined in this paper. It shows that there is a great cohesion value when the water content in the optimal water content. C is increase first and then decrease before and after the optimal water content. There is a same law for internal friction that increase first and then decrease before and after the optimal water content. The decline segments become longer before the optimal water content and become shorter after the optimal water content. The residual thrust of the piles is minimal when the soil is at optimum water content. The muddy of bedding slope would be accelerated when the water content increases. C and would decrease; residual thrust would increase on the other hand. For the design of roadbed slope, the blind ditch on the left slope must be dug to drainage the water so that the groundwater would be decreased of flowing from the left slope to the roadbed. The drainage ditch must be prevented the leakage of water from flowing to the roadbed. The Blind ditch in the roadbed slope must be constructed to decrease the softening erosion of groundwater for the weathered interface.