Research On Ground Surface Settlement And Control Induced By Double-line Tunnels Construction

Generally,urban subways are composed of two-line tunnels.The construction of double-line tunnels is different from that of single-line tunnels.The law of settlement change caused by excavation,based on the characteristics of the stratum and the surrounding environment,put forward practical and reasonable settlement control measures,which have a significant effect on the construction of the subway.In this paper,an in depth study of the excavation in xing-qing section has been carried out,The tunnel has a shallow depth and is constructed by mining method.The combined method of the theoretical calculation and numerical simulation is adopted to analyze the results of ground subsidence measurement and control measures caused by excavation of Xing-qing tunnel of Xi'an Metro Line 5.The following work has been done:(1)Combined with the excavation of the Xingqing section tunnel of Xi'an Metro Line 5,according to the difficulties and difficulties in the construction process,With the comprehensive consideration of engineering geological conditions,The reinforcement principle,advantages and disadvantages and applicable scope of various pre-reinforcement technologies are compared and analyzed,and the pre-reinforcement technology adopted by the project is compared and introduced.,and the control effects are discussed.(2)The MIDAS GTS NX software was used to establish a three-dimensional model of tunnel construction.According to the geological conditions and supporting structure,the material parameters were selected to calculate the ground settlement and the internal force changes of the supporting structure caused by tunnel construction under different excavation methods,different construction sequences and different sections,and the control measures were also discussed(3)The on-site monitoring data were grouped,and the lateral settlement monitoring points of each section were analyzed to study the effects of different section sizes and different construction methods on surface settlement.Comparing the numerical simulation with the field monitoring data,it shows that the numerical simulation has a certain guiding role in the construction,and through the simulation and optimization of reinforcement,it shows that the appropriate enlargement of the reinforcement scope can control the surface subsidence very well.It is found that under the existing pretreatment conditions,the maximum settlement of part of the section reaches 43.3mm,,and the maximum settlement of part of the section is 16.6mm,which is much smaller than the warning value of 30mm,Pre-reinforcement optimization is performed for sections exceeding the warning value to control settlementThis paper combines the construction of Xing-qing section tunnel of Xi'an Metro Line 5 Analysis of ground settlement and control measures caused by double-line tunnels construction.It has certain reference to the follow-up construction and stratum settlement control of Xi'an subway.