Study On Equivalent Mechanical Parameters Of Granite Fracture Rock Mass

In natural world, there are a lot of joints in rock mass. These joints weaken the rock mass, so there are big differences of the mechanical properties between the rock mass and the rock. In practical engineering, it is often needed to know the equivalent mechanical parameters of the rock mass, it is usually unrealistic to test the rock mass properties by on-site measurements. How to acquire the equivalent mechanical parameters of the rock mass through the rock test is very important to guide the actual project, which is the main content of this study.This thesis uses granite joint rock mass as a background. After the systematic review of the researches and results in rock joints three-dimensional network simulation techniques filed, new ideas and methods was proposed:first investigate the joints of the rock, then obtain useful information by Processing the photos of the joins, third calculate the basic parameters of the rock mass, fourth understand the size effect of the rock mass by using finite element simulation and determine the equivalent mechanical parameters of joint rock mass through the representative elementary volume (REV).Though the actual survey of the outcrop joints in field area, the tendency of the joints, dip of the joints, the position of the joints, the corresponding rebound value and picture of joint trance was got. We progress the pictures to obtain the joint roughness coefficient of the fracture and use Barton formula to calculated Shear Strength. By statistical analysis, the fracture of the joint rock mass was grouped, and then we get the statistic parameter of the fracture in this field area.Then, make the finite element modeling based on stochastic discrete fracture network and rock and fracture parameters according statistics. The rock was modeled used damaged plasticity model for brittle material and fractures were modeled by frictional interface elements. In this process, it is needed to establish many Abaqus models in different size and calculate the compressive strength of each of them to determining the REV by analysis these parameters. Last, calculate the equivalent mechanical parameters of the rock mass based on REV.