直立岩质切向边坡岩体原位直剪试验研究

Study on in-situ shear test of rock mass tangential erect rock slope

针对岩质切向边坡发生剪切破坏时其剪切面难以预测,同时在强风化作用下造成岩体性质差异使得岩体强度参数难以准确获得的问题,本文以遵义市花台坡高边坡为工程背景,开展直立岩质切向边坡岩体原位直剪试验研究.得出切向边坡岩体剪切过程受到走向与坡向垂直的结构面控制,剪切面首先沿此方向上的节理裂隙扩展,硬岩剪切过程中剪切面呈现“台阶”型破坏面,粗糙度小;较硬岩剪切破坏面呈现“波浪”型,起伏剧烈,粗糙度大;软岩发生整体剪断,剪切面较为平整;而含贯通性倾坡外结构面的岩体则沿结构面发生剪切破坏,剪切面顺直平滑.与室内三轴试验对比后发现,现场原位直剪试验结果很好地反映了工程实际情况,特别是对于薄层软硬相间的岩体,能提供更为准确的岩体强度参数.

When the shear failure of rock tangential slope occurs,the shear plane is difficult to predict,and the difference in rock mass under strong weathering makes it difficult to accurately obtain the rock mass strength parameters.In this paper,based on the high slope of Huataipo in Zun Yi City,the in-situ direct shear test of upright rock tangential slope rock mass is carried out.The results show that the in-situ direct shear test of the tangential slope is controlled by the stnictural plane perpendicular to the slope direction,and the shear plane first expands along the joint fissure in this direction.During the hard rock shearing process,the shear surface is"stepped”failure surface with small roughness.The softer rock shear failure surface is"wave”type,with undulating undulation and large roughness.The soft rock has an overall shear and the shear surface is relatively flat.However,the rock mass with structural planes is sheared and destroyed along the stnictural plane,and the shear surface is straight and smooth.Compared with the indoor triaxial test,the on-site direct shear test results reflect the actual situation of the project,especially for the thin-layer soft and hard rock mass,which can provide more accurate rock mass strength parameters.