Mechanical Deformation Parameter Study On The Rock Mass In The Deep Tensile Fracture Zone Of Left Abutment And Above For Jinping I Hydropower Station

The large project of Jinping I Hydropower Station was the first step of 5 steps of planning stations from Kala to Jiangkou in the downstream field along Yalongjiang main stream. In researching zone, there were complex geolocial conditons, precipitous bank slope and intense epigenetic reformation. So the stability problem of high slop was remarkable. Deep tensile fracture rock mass had been focused on by people since the stage of dam site selection, which was the key to the whole project safety.Based on geological environment and field investigation, the structure feather of deep tensile fracture rock mass was summarized. By the analysis on deformation phenomena on-site, monitoring data of deformation, simulation of FLAC3D, the parameters of deep tensile rock mass were back analyzed with orthogonal test method. Study contents and achievements were mentioned below:(1) Based on the geological conditions, and the early excavation of slopes and adits, the structure characteristics of deep tensile fracture rock mass of left abutment and above were fully studied, which included characteristics of lithology and lithological association, and characteristics of engineering geology and combination of structural planes. Further, the subarea of rock mass structure and classification of rock mass quality were done, and the rock mass structure model of the slope was established.(2) By the analysis and analogy on the data of rock mass deformation test and acoustic wave test at the stages of feasibility study and construction, rock mass parameter range of inverse model and deformation parameter range of deep tensile rock mass were given.(3) By the analysis on early deformation data and monitoring data, the controlling structural planes were fully understood, which provided foundation to the generalizability of geological model, and provided important reference to parametric inversion.(4) Based on the overall analysis on rock mass structure, and controlling structural planes for the left abutment and above, 3D numerical model was established. By use of simulation analysis of FLAC3D, forward simulation was done 25 times according to different parameter combination. Further more, using the method of orthogonal design, the sensitivity of deformation parameters was analyzed. At last, suitable deformation parameters range to the project was made sure. Modulus of deformation ranged from 1.8 to 2.3, and Poisson ratio ranged from 0.3 to 0.32. A group of parameter combination was selected for the simulation analysis of FLAC3D. It was proved that inversion parameters were in accord with fact as a whole.