泥岩层面抗剪强度室内大型剪切试验研究

Large-Scale Laboratory Shear Test and Study on Shear Strength of Mudstone Layer

对三峡库区多条高速公路边坡工程的调查发现,目前无论在边坡稳定性计算还是在其治理工程设计方面,控制性软弱结构面的参数选取依据不充分,天然抗剪强度和饱和抗剪强度的取值差异性不大。采用大型室内试验,研究库区典型珍珠冲组地层中泥岩结构面(密闭型)的抗剪强度。试验研究结果表明:试验获得的峰值抗剪强度与采用Barton和Choubey经验公式的计算值相当;室内试验获得的干燥条件下泥岩层面的峰值抗剪强度与饱和工况下的残余抗剪强度有显著差别,与目前工程上采用的不同,这些认识对岩质边坡治理设计参数的获取具有参考价值。

The investigation on the side slope projects of a number of expressways in the Three Gorges Reservoir Area shows that at present,in aspects of both slope stability calculation and treatment engineering design,the parameter selection of the controllable weak structural plane has no sufficient basis,as the values for natural shear strength and saturated shear resistance have no necessary difference.After a large-scale laboratory test and study on the shear strength of mudstone structure（ airtight type） in the typical pearl formation in the reservoir area,the results show that the peak shear strength obtained from the test is equivalent to that calculated by Barton and Choubey empirical formulas.The peak shear strength of mudstone under drying conditions obtained from laboratory tests is significantly different from the residual shear strength under saturated conditions.Different from the current engineering practice,this understanding is referential to obtain design parameters for the treatment of rock slope.