Study On Surface Subsidence Control Of Shallow Buried And Undercutting Subway Tunnel In Xiamen Area

In the subway tunnel shallow buried construction,Especially in the surrounding surface or underground both buildings and facilities-intensive areas,Excavation process Surface subsidence control is the most common and most important risk control point.Because the tunnel excavation surface settlement is too large than the alarm value will lead to many very serious consequences,Such as the surface of the building tilt or even collapse,destruction of underground pipeline damage,both the road structure because of a large number of settlement damage and so on.Compared with the shield tunneling construction,the use of shallow burial is still not particularly popular,when the shallow buried excavation process encountered a variety of complex geological conditions and existing construction pipeline facilities,this time for the excavation process surface subsidence The study of control is particularly important.This paper mainly focuses on the settlement control of the shallow buried and deep excavation of the Zhongshan Park Station on the Metro Line 1 in Xiamen.The main contents of this paper are as follows:(1)Describes the theory of consolidation and settlement of the basic soil,and summarizes the basic law of the lateral longitudinal settlement of the shallow excavation.(2)According to the introduction of geological conditions in Xiamen area,the specific construction methods and monitoring points are introduced.According to the specific geological conditions,the model is assumed and simplified.The settlement value is obtained by the three-dimensional finite element numerical simulation.It is feasible to obtain the model by the actual engineering monitoring and the comparative trend analysis.(3)Based on the numerical simulation of the previous chapter,the main stages of subsidence are analyzed,and the influencing factors of surface subsidence in the main stage of settlement are discussed.Considering the increase of the stiffness,structure and initial support stiffness of the advance support structure,it is found that the effect of increasing the support stiffness on the settlement control of the surface is generally analyzed.The sedimentation curve analysis shows that the large amount of ground stress caused by excavation to the initial support time Settlement is larger.Finally,consider the grouting reinforcement grouting,so as to reduce the impact of excavation disturbance,and secondly to a large extent inhibited the excavation of the groundstress release,through the numerical analysis curve can be very intuitive to see the excavation To the completion of the support phase of the surface of the settlement value greatly reduced,indicating that through the excavation surface grouting reinforcement stability is indeed effective.Of course,a single rely on a control measure is far from enough,the need to rationally use a variety of measures to meet the requirements of surface subsidence control at the same time to do with the support structure with the use of cost savings.