Study On The Rock Mass Structure Effect Of Large Rock Slope During Excavation

The rock mass structure is that the mode of combination and array of different kinds of rock mass structure units. The discontinuity and mass are the most basic units and key factors of rock mass structure. The rock mass structure controls the mechanical property, characteristic of deformation, failure etc. The function of the rock mass structure is far stronger than the function of the rock material. Therefore, the deformation of rock mass is not just the deformation of material, but more the deformation of the rock mass structure; the rupture of rock mass is not just the function of material, but more the function of the structure destruction. Once the rock mass is taken part in the engineering activity, the deformation of rock mass will occur corresponsive. This paper is based on a great lot of geological investigations of high slope no.4 in Xiaowan Hydropower Project on Lancang River of Yunnan. Meanwhile, this paper attach most important to the operation of rock mass structure , the deformation of rock mass and the mechanism of deformation corresponsive is researched while large and high rock slope is excavated.. Then the stability of high slope after excavation is evaluated reasonable. At last, the support measure is advised. The key contents and conclusions are as follows:1. Based upon excavation of slope, the rock mass structure of slope no.4 is researched completely. The researching consists of the generation analysis of different discontinuity, the geological classification of discontinuity, the investigation of different discontinuity, especially the low-angle dip discontinuity is done. At last, the mode of rock mass structure is established.2. Based on the failure traces of slope during excavation, considering the characteristic of rock mass structure, the mechanism of deformation and the mode of deformation is analyzed, meanwhile, the mode of deformation and failure is generalized.3. The typical stepladder failure mode is researched by numerical simulation. The dip and connectivity of the discontinuity of middle and low-angle dip is taken account of, to research the law of deformation and failure.4. By 3DEC DEM numerical simulation, the different characteristic and combination of discontinuity (â…¢,â…£,â…¤) is accounted especially ,to simulate the operation of rock mass structure during exaction. According to the characteristic of deformation, the support measure is advised, meanwhile the effect of supporting is simulated.5 By the limit equilibrium theory, the stability of slope no.4 is calculated and analyzed.