Study On Seepage Mechanics Characteristics And Sectional Waterproofing And Water-Drainage Of Underwater Tunnel By Mining Method

Currently, underwater tunnels of our country is in flourish development. However, constructions of underwater tunnels is very different from common mountain tunnels. The lack of techniques on construcing underwater tunnels by mining method, and researches on sectional waterproofing and water-drainage tecnique are little both at home and abroad. Therefore, it is urgent for practical constructions to research seepage mechanics characteristics in construction period and sectional waterproofing and water-drainage of underwater tunnels by mining method.With the help of finite difference software FLAC3D, based on the theory on the fluid-mechanical interaction, combined with the Xiamen-Xiang'an subsea tunnel, and Liuyanghe underwater tunnel, the thesis mainly implements research on seepage mechanics characteristics in construction period and sectional waterproofing and water-drainage of underwater tunnels by mining method. The contents and the conclusions are listed as following:1. Introduced mechanical effects of high hydraulic pressure on underwater tunnels, fluid-mechanical interaction principia, equivalent continuum mathematical model of fluid-mechanical interaction. This thesis adopted equivalent continual material to study the relevant contents.2. Based on the fluid-mechanical interaction principia, the thesis researches on pore-water pressure acted on secondary lining on condition of limited drainage, and the results reveal the relationship of discharge of water and average pore-water pressure on secondary lining. Meanwhile, the thesis also make a research on structural internal forces on condition of complete-drainage, and the results reveal the effects of grouting circle on mechanical behavior of secondary lining.3. Based on the fluid-mechanical interaction principia, the thesis also makes a comparative analysis to some underwater tunnel by mining method which employes different drainage boundaries, and the results reveal seepage mechanics characteristics of surrounding rocks and supporting structures in construction period of underwater tunnel by mining method.4. The thesis also makes a research on pore-water pressure acted on the outer boundaries of supporting structure and cushion, and on the distribution regularity of seepage field of surrounding rocks, when the technology of sectional waterproofing and water-drainage is employed in underwater tunnel. Thereafter, the thesis researches on effects of the permeability coefficient of cushion in transitional section on pore-water pressure acted on surpporting structure and cushion, and on the discharge of water in drainage section. Finally, the thesis analyzes the pore-water pressure acted on primary lining when the calculation is not in convergency, and the result tells us the positions in which water accumulates easily on process of convergency.