STUDY ON SUPPORT DESIGN FOR SUBSEA TUNNEL
Abstract Supports characteristics and supports design of Jiaozhow Bay subsea tunnel, which is the second self-building tunnel in China, are studied in this paper. The rock cover of Jiaozhow Bay subsea tunnel is relatively thin, so tunneling in unfavorable geologic bodies requires some special considerations, since misjudgment in support design results in costly failures. Numerical method is taken to study the influence of stress filed on seepage field and the effect of the changes of surrounding rock permeability coefficient, water level, permeability coefficient and thickness of grouting ring to seepage field are analyzed. According to the research, the pore water pressure and water inflow induced by tunnel excavation can be hardly affected by arching effect. If keeping the water level above horizontal plane fixed, the distribution of pore water pressure will not change with permeability coefficient of surrounding rock. The water inflow increases with the increase of permeability coefficient of surrounding rock or water level height above surrounding rock. The decrease of permeability coefficient and the increase of thickness of grouting ring can both reduce ground water inflow, but there exists an optimal value in grouting parameters. In practice the decision should be made carefully between economy and water plugging effect to confirm the optimal grouting parameters. Probabilistic numerical approach is adopted for the design of subsea tunnel supports, using hyperstatic reaction method. From the calculation result it is possible to obtain the probabilistic distribution of the support safety factors and then design the support for Jiaozhow Bay subsea tunnel on the basis of the given probabilistic curve. Whole process optimization for Jiaozhow Bay subsea tunnel is put forward, which includes optimized support parameters acquisition, design variable sensitivity analysis and evaluation of the optimal design. According to the characteristics of subsea tunnel in Jiaozhow Bay, optimization method mentioned above is used to make optimization analysis. This study can provide instructional references for both design and construction of the Jiaozhow Bay subsea and it can be also useful for similar projects.
subsea tunnel physical modeling water pressure probabilistic design optimization design
FANG Qian ZHANG Dingli LIU Yan LI Pengfei
Tunnel and Underground Engineering Research Center of Education Ministry,Beijing Jiaotong University,Beijing 100044,China
国际会议
香港
英文
1-6
2009-05-19（万方平台首次上网日期，不代表论文的发表时间）