Study On The Influence Of Subway Transfer Station Construction On The Deformation Of Adjacent Existing Station And Control Measures

With the rapid development of China’s economy and the increasing urbanization rate,the problem of urban traffic congestion has become increasingly serious.As an efficient and convenient transportation mode in urban rail transit,subway has become an effective way to solve the problem of traffic congestion in major cities.Due to the long construction period of subway,the construction of different subway lines at the transfer station can not be completed at the same time.Inevitably,the foundation pit construction of new subway stations crosses the existing operating subway stations.Therefore,how to carry out reasonable risk analysis and take effective protection measures for the adjacent existing operating stations during the construction of new subway stations is an urgent problem to be solved at present.In view of this,this paper relies on the cross transfer foundation pit project between xinjianguoji Road Station of Zhengzhou Metro Line 4 and Salmonella station of existing line 2.Firstly,the intelligent robot automatic monitoring system is used to automatically monitor the track and side wall of the existing station during the foundation pit excavation of the new station,reveal the displacement change law and carry out risk analysis.Secondly,ABAQUS finite element software is used to simulate the construction process of Guoji Road Station of new line 4,and through parameter analysis,the influence laws of different construction schemes and different support structures on the existing metro station of line 2 and the surrounding environment are revealed.Finally,reasonable and effective protection measures are put forward.The main research contents are as follows:(1)Based on the field test,the intelligent robot automatic monitoring system is applied to explore the application value of the system in the field of the project.The three-dimensional real-time deformation data of the upper and lower tracks of the existing line 2 Salmonella station and the station side wall during the foundation pit excavation of the new station are collected in real time,the deformation law of the existing station is revealed,and the risk analysis is carried out.(2)Based on the numerical simulation,an overall analysis model considering the foundation pit excavation and support system of existing operating stations and new stations is established,and the horizontal and vertical deformation development law of the track and side wall of the upper and lower tracks of the existing line 2 Salmonella station and the surrounding surface settlement law are studied during the foundation pit excavation of Guoji Road Station of line 4.The field measured values and numerical simulation results are compared and verified to prove the accuracy of the model.On this basis,the deformation laws of the existing station and the surrounding environment are compared through three excavation schemes:first East and then West,first West and then east,and east-west synchronization.The results show that the East and west sides are excavated symmetrically at the same time,which has the least impact on the existing line 2 station.(3)Based on the analysis results of the above field test and numerical simulation,combined with the engineering example,through multi-element analysis,the influence law of different diaphragm wall thickness and support stiffness on the surface settlement of the existing station and the surrounding ground in the foundation pit excavation and support structure of Guoji Road Station of new line 4 is simulated.The results show that larger diaphragm wall thickness and higher support stiffness can significantly reduce station displacement and surface settlement and improve engineering safety,but there are also optimal diaphragm wall thickness and support stiffness.(4)Based on the above research,comprehensive control measures are proposed for the impact of foundation pit excavation on cross existing buildings and structures under such poor geological conditions,including the selection of reasonable foundation pit excavation mode,appropriate support structure form and reinforcement of existing stations.