Research On Construction Technology Of Tunneling Through Fully Watered Mylonite Strata Below Susceptible Buildings

When the shallow tunnel is under construction,the tunnel is shallow and often crosses the surface constructio.In addition,the tunnel itself is under water-rich geological conditions,not only to control the amount of water inrush,to avoid the occurrence of water inrush and mud,and to ensure the stability safety of the tunnel,it is also necessary to control the amount of sinking of surface and surface sensitive buildings to avoid cracks or even collapses caused by uneven settlement.Taking the Shenzhen East Transit Expressway Link Project(referred to as the"East Link"project)to the bonsai world park section as the support project of this article,through field investigation,theoretical analysis,numerical simulation research methods have achieved a series of research results,Specifically,the following research work has been done:(1)This paper analyzes the key and difficult problems in the connection line project of the eastern transit expressway in Shenzhen.Through the numerical simulation,three excavation methods are studied:1 step method,2CRD method(crossing partition wall method),3 double side wall guiding method,The influence of the above three excavation methods on the stability of surface sensitive buildings is obtained,and the key processes of excavation of double-wall guide pit method are studied.The excavation area of key processes is optimized,and the stability of ground-sensitive buildings and tunnels is obtained.A more reasonable excavation method provides engineering reference for the actual project excavation.(2)Through numerical simulation,the influence of different thickness and different range of grouting reinforcement ring on tunnel seepage field and stress field is studied.The influence of surface and surface sensitive buildings is also analyzed.The research shows that the tunnel has reasonable grouting reinforcement ring thickness and reasonable grouting range.It provides a reference for the project to implement grouting reinforcement to control the settlement of surface buildings.(3)The monitoring measurement method is introduced.The field monitoring data and numerical simulation data are compared and analyzed.The analysis shows that there is a certain error between the numerical simulation and the field monitoring data,but the rules obtained by the two are consistent.The above research results guide the construction of the tunnel,the stability of the tunnel and the stability of the surface construction are well controlled.At the same time,the research results of this paper have played a good reference for similar projects.