Research On Theory And Application Of Waterproof And Drainage System Of Shallow Tunnels With Drilling And Blasting Method

ABSTRACT:Tunnel waterproofing and drainage is a key factor to constraint tunnel construction and operation security during underwater tunnel construction, due to its own characteristics and difficulties of underwater tunnel, tunnel waterproofing and drainage technology has drawn increasing concern of the engineering sector. Based on the field construction technology of Liuyang River tunnel,Xiamen Xiang’an harbour tunnel,Qingdao Jiaozhou bay tunnel, Xiangjiang tunnel and a large number of tests, the theory and technology of underwater tunnel have been studied in ditail, the main research results are as follows:(1) Based on extensive collection of waterproofing and drainage technology of underwater tunnels which have been built at home and abroad and waterproofing and drainage experience of mountain tunnel and the city subway tunnel in China, Proposed waterproofing and drainage technology of urban shallow underwater tunnel with drilling and blasting method should follow the principle of "blocking row combination, limited emissions".(2) Under the condition of water shutoff emission limitation, put forward the method of determining underwater tunnel allowed emissions which based on grouting and drainage costs balanced, and applied to the Xiangjiang tunnels, calculated allowing average emission of the underwater tunnel is0.34m3/m.d, which lower than0.43m3/m.d abroad emission level.(3) Qingdao Harbour Tunnel and Xiamen undersea tunnel as the basis, through field experiments, established three kinds of the classification target grouting technology of undersea tunnel,including Full-face target grouting, plugging the next row of the target grouting and behind the lining radial grouting. By numerical simulation and theoretical calculation method, determined the Xiamen undersea tunnel deep weathering slot full-face target grouting and Qingdao Harbour Crossing fault fracture belt blocking the bottom row grouting main objective of grouting parameters.(4) Tunnel waterproofing and drainage lining water pressure distribution model test showed:under conditions of full closure, lining behind the water pressure is increased with the increase of the external water pressure and beared all the construction of the external water pressure; under the conditions of pluggingemission limits, the lining behind the water pressure is decreased with increasing tunnel discharge. (5) Through indoor model test of the non-woven fabric impact on the water pressure distribution of tunnel surrounding rock and lining behind, showed that under the water shutoff emission limitation conditions, the laying of non-woven and water pressure behind the laying of the non-woven lining with tunnel discharge decreases, the laying of uniform distribution of water pressure in non-woven measuring point, lining less strain; under variable head conditions, non-woven lining behind the water pressure head is positively related to the laying of non-woven fabrics and laying headthe process of change, laying non-woven measured water pressure more focused, lining structure less strain.(6) Based on the the tunnel deformation joint is the weak link of the underwater tunnel waterproofing, through theoretical analysis, numerical simulation and on-site verification, the underwater tunnel cancelling deformation joint lining structure can meet safety requirements.(7) Created underwater tunnel blockage of the drainage system test platform, through a large number of experiments, the results show that:blind pipe and drain sediments accumulated quality and the growth gradually increased with time increased; due to the initial support impermeable properties and resistance to erosion, seawater plays role of filtering, the blind pipe sediment quality is more than the drain pipe and more easier to clogging; put forward the governance of tunnel drainage system that periodic inspection, periodic maintenance, regular cleaning and maintenance of the drainage system.