Study On The Settlement Of Ground Surface And The Technology Of Control Deformation In Shenzhen Metro Construction

The tunnel of Shenzhen metro Line 5 cross the silty clay,completely weathered and highly weathered hormfels and granit. The underground water of this area is abundant. The geological conditions are very complicated in the tunnel. The geological hazards like the gushing water and sand and the collapse of tunnel may happen during construction period. That will lead to the settlement of ground Surface. The settlement of ground surface is very important to the safety of ground structures, so we must pay more attention to it. This paper refers the case project of Shenzhen Metro Line 5, researches the settlement of ground surface and the technology of control deformation during construction. The main contents of this paper were listed as follows:1. Based on the studies on the settlement of ground surface and the technology of control deformation, the main influencing factors of the ground surface settlement and technology of control deformation during construction are analyzed.2. In this paper MIDAS/GTS software is used to analyse the tunnel of Bid 5305 Section. A detailed comparision is made between the actual and calculated values, Values of ground surface settlement during pump water occupy total settlement values more than 50% in the construction3. The numerical analysis of No.l shaft of bid 5305 section.of is performed using FEM based on total stress theory and elasto-plastic fluid-solid coupling theory,and is compared with actual measurement value. It has been showed that it is adequate to estimate the ground surface subsidence in the course of tunnel construction with FEM based on elasto-plastic fluid-solid coupling theory.4. Based on the studies on preservation techniques of ground structures and the technology of control deformation, the norms of the ground subsidence for tunnel construction allowed by ground structures are studied.5. Based on actual data, the paper illustrates the law of deformation of the ground surface settlement on the course of the tunnel crossing the dormitory building. futher more thispaper discusses the importance of technology of control Deformation during construction6. Based on the project practice of the air channel of the Shenzhen Metro, the design and built process of the horizontal rotating-jet grout pile is introduced, the result of the reinforcement is simulated by MIDAS/GTS. After comparing actual data, the conclusion is that the reinforcement of the the horizontal rotating-jet grout pile were adopted with rather satisfactory results.