3D Engineering-Geological Modeling And Analysis To The Left Bank Slope And Foundation Treatment Project Of Jinping First-Level Hydropower Station

The stability of arch dam mainly depends upon the rock mass of the abutment, whose engineering-geological condition is very important to the dam. The left abutment slope of Jinping first-level arc dam is in a complex geological condition consist of such harmful geological structures as f42-9, f5, lamprophyre veins and fractured zone. Reinforcement treatment cavern group of the left abutment slope, as resistance rock of the arch dam, has the characteristics of huge quantity, intense arrangement, and large construction disturbance; if the construction can not be completed on schedule, the progress of pouring dam concrete will be delayed.Analysis to the geological condition and treatment measures is very important to the security and stability of the arch dam, and is of great significance to ensure the progress of dam construction.This paper researched in the problem of 3D engineering-geological modeling and analysis based on the left bank slope of Jinping first-level arch dam and foundation reinforcement engineering, the main research work and achievements are as follows:(1) Engineering-geological modeling of classification objects in the left bank slope and dam foundation treatment project. To establish high-precision engineering geological model, NURBS-based hybrid data structure was used in VisualGeo system, which is a three-dimensional geological modeling and analysis platform for hydraulic and hydroelectric engineering. Two classification objects' models were established, one was natural object models such as the DTM, rocks, faults, dykes, and the other was artificial hydraulic structure models such as the arch dam, concrete pedestal, excavation surface and reinforcement treatment cavern group. Rock mass quality classification model of the project area was established.(2) Based on the three-dimensional geological model which had been established, a series of three-dimensional geological analysis has been conducted, such as excavation geological analysis, possible sliding mode analysis of left slope, simulated excavation analysis, rock mass quality classification analysis and flat cutting analysis of reinforcement treatment cavern group.(3) Combined with the geological information exposed by excavation in the left bank slope and foundation treatment project, dynamically updated methods of the three-dimensional geological model was proposed, and its application methods in the dynamic design in the project has been further developed.Three-dimensional geological analysis for geological conditions and treatment measures of the left bank slope of Jinping first-level arch dam and foundation reinforcement engineering has been performed, whose results can provide support for engineering design and construction optimization, and can be used for references in similar projects.