五盂高速公路顺层岩质边坡变形破坏模型试验

为揭示开挖和降雨对顺层岩质边坡稳定性的影响,以山西五盂高速公路顺层岩质边坡为对象,通过大型物理模型试验研究了含软弱结构面顺层岩质边坡在开挖及降雨条件下的变形机理.研究结果表明:降雨条件下,含单层软弱结构面边坡主要表现为沿软弱结构面的多级牵引式滑动破坏;含双层软弱结构面顺层岩质边坡滑动破坏受降雨的诱发作用更为明显,其中软弱结构面作用主要表现为两方面,一方面为雨水对结构面本身的软化使其强度降低从而形成滑带,另一方面为软弱结构面的存在减弱了雨水向下层岩体的入渗,导致其上覆岩体迅速饱和,强度急剧降低,上覆破碎岩体沿滑动面发生大规模的整体破坏.可见强降雨是此类边坡破坏的主要诱发因素也是重要的致灾因素.

Model Tests Study of Deformation and Failure of Bedding Rock Slope, a Case Study in Wuyu Expressway

Landslide caused by bedding bedrock is a geological hazard in the construction of highway and other projects in mountains area and hilly area. In order to reveal the influence of excavation and rainfall on the stability of bedding rock slope, taking the bedding rock slope of Wuyu expressway in Shanxi Province as an object, the deformation mechanism of bedding rock slope with weak structural plane under the conditions of excavation and rainfall was studied by using large-scale physical model test. The method of combining SAA array displacement meter, 3D laser scanner, photogrammetric technique and artificial deformation measurement is used to monitor the displacement of the bedding rock slope model.The results show that the deformation mechanism of the slope with single layer of weak structural plane is mainly the multi-stage traction sliding failure along the weak structure plane. The induced effect of rainfall on the sliding failure of the bedding rock slope with double layers of weak structural planes is particularly obvious. Weak structural plane function mainly for two aspects, on the one hand to the softening of structural plane itself for rain eventually make its development into the overall sliding failure of sliding zone, on the other hand, the existence of weak structural plane make it to abate the infiltration of rain to the lower level of rock mass. As a result, the overlying rock mass quickly becomes saturated and its strength decreases sharply. When the rainfall reaches a certain degree, the overlying fractured rock mass will have a large-scale overall failure along the sliding surface.It can be seen that heavy rainfall is the main inducing factor of slope failure and also an important factor of disaster.