| With the development of urban construction and underground space, the shield tunneling, due to its advantages of well geological adaptability and rapid operation as well as weak disturbance to surroundings, becomes the preferred construction method of subway, river-crossing and water-delivery tunnels, which is also verified by quantities of successful cases. Quite a lot of latest construction techniques of shield tunneling are demonstrated to meet the requirements of particular underground projects. Currently in China, it is urgent to solve the various problems encountered in the construction and exploit new techniques of shield tunneling. To develop the construction techniques of shield tunneling combined with engineering practice is a significant research subject in China.Based on the shield tunnel between Fanshen Station and Lingzhi Station of Shenzhen metro line 5, this paper studies the key technical issues of shield construction beneath buildings and structures, joint waterproofing, transportation organization and shield construction in tunnel section by mining method, along with the potential negative effects. Integrated with the practical situation of this project, the corresponding construction solutions are proposed.(1)Since the excavated position of shield tunnel is regarded as the key influence factor, the impact of shield construction on the adjacent buildings and structures(pile group), with different buried depth and horizontal distance to piles, is studied by the methods of theoretical calculation and numerical simulation. And the solutions to ensure construction safety are put forward.(2)According to the investigation and survey of shield tunnel projects in China, in the aspects of joint structure, the waterproofing parameters and material of elastic rubber gasket, the joint waterproofing measures which is appropriate for this project are proposed based on the engineering practice.(3)The influence factors of transportation efficiency and the problems encountered in transportation organization of Earth Pressure Balance(EPB) shield are analyzed. By the selection and consumption estimate of main construction materials, the transportation equipment and organization scheme are determined. The corresponding optimization measures are worked out by improving transportation capability of equipment and proper organization scheme.(4) Aiming at the risks, such as difficult shield attitude control, stuck shield, joint water leakage as well as segment cracking and uplift, of shield construction in tunnel section by mining method, the technical solutions are put forward to reduce the construction duration and costs and effectively lower the risks.Integrated with the practical situation of shield tunnel between Fanshen Station and Lingzhi Station of Shenzhen metro line 5, aiming at the problems in construction process with special geological condition, this paper proposes the comprehensive construction solutions of EPB shield, which completes the safety control techniques of shield tunneling and reduces the negative influence of inappropriate measures on the tunnel structure in operation. The construction solutions put forward in this paper guarantees the engineering safety and obtains good efficiency both in social and economic aspects, providing the similar projects with reference. |
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