Study on the Stability of Adjoining Rock and the Liner Structure of the Tunnel under the High External Waterpressure and High Geostress
|Course||Hydraulic Structure Engineering|
|Keywords||DEEP TUNNEL Support reinforcement High external water pressure Nonlinear finite element Highland stress Simulation Analysis Stability of surrounding rock Load-bearing structures|
In recent decades, to meet the needs of rapid economic and social development, the rapid construction and development of a variety of purposes in the world, the tunnel project, its manifestations, and the trend is increasing tunnel length and depth of the growing. Great depth will enable Tunnel in encounter, such as high external water pressure and high-pressure water gushing, Highland stress and rock burst Highland temperature, high gas harmful gases, such as a series of geological disasters, this rapid development constraints deeply buried tunnel construction The main factors. The average length of 16.625km, four diversion tunnel of Jinping Hydropower Station Maximum depth of about 2525m tunnel line elevation at the to stress maximum principal stress value of 54MPa, the project belonged to the Highlands stress zone. Early 4km long exploratory tunnel construction process has several larger gushing, the largest single point of gushing water amounted to 4.91 m to 3 / s long exploratory tunnel closure after water pressure up to 10.22Mpa high external water pressure in the project area issues outstanding. Such a great depth, high external water pressure on the tunnel project under construction in the Highlands stress is still rare can learn from similar projects, and research in this area is also rare. This makes the construction of the tunnel project is facing great challenges. This article is in the surrounding rock as the main load-bearing structure, support and surrounding rock modern tunnel design theory based on the study of high external water pressure and highland tunnel surrounding rock stability under stress and supporting structural safety. First, seepage control scheme for the external water pressure grouting reinforcement ring and lining on how reasonable allocation problem. Then, on the the basis of in-depth research project area high external water pressure and highland stress distribution law and the rock mass characteristics, establish a high stress, high external water pressure tunnel surrounding rock structure nonlinear finite element simulation model, and then consider the tunnel excavation process, the role of water load history derived by computational analysis different Diameter different the different grouting Circle permeability coefficient and the grouting circle depth and different excavation process and surrounding rock and supporting structure stress displacement and plastic zone. The results show that, if it makes Jinping engineering diversion tunnel grouting circle surrounding rock has a good anti-seepage performance, high external water pressure control outside the grouting circle, together with water permeability is relatively good support structure and drainage measures, grouting circle surrounding rock become the main load-bearing structure, and the lining and grouting circle co-hosts, can guarantee the structural safety of the surrounding rock stability and support. Finally, the surrounding rock as the main load-bearing structure design thinking as a tunnel support design principles, reinforced concrete wall rock and supporting structure design, and the successful practice of blocking construction through specific long exploration adit, further on the surrounding rock as the main load-bearing structure of the design ideas been proven.