Studying The Optimization And Dynamic Construction Technology In Subway Construction With Complex Condition

With the engineering background of the 202 section of the Dalian metro station and the shield section,the geological conditions of the construction area are very complex,the groundwater is rich and the karst cave is developed,and the surrounding rock presents a typical"soft,hard,hard,hard and hard unequal state".The undercut station is located under the shallow pile elevated bridge.The shield construction needs to pass through the risk buildings such as the ancient river road,which has the existing road,railway and"V type".In order to solve the above problems,the advanced FLAC^3D numerical simulation technology is used to optimize the construction scheme,as well as to strengthen the strengthening measures,and correct the construction parameters by using intelligent monitoring and parameter reverse analysis technology,then the dynamic construction is carried out.FLAC^3D numerical simulation technology is able to simulate the three-dimensional structure of soil,rock and other materials and analyze the plastic flow.The application of FLAC^3D numerical simulation technology in the construction of the dark excavation station successfully carried out the comparison of the large section shallow buried air duct step method,the CD method and the CRD method,determined the advantages of the CRD method in controlling the horizontal convergence and the surface settlement,and found the weak link of the CRD work method in the stratified and step excavation construction.At the same time,the construction method of CRD fast excavation for big arch foot is put forward and innovated.Aiming at the problem of excavation crossing shallow pile elevated bridge,the stress system model of pile foundation,rock soil and tunnel is set up.The numerical simulation of the stress structure of the bridge system by tunnel excavation is carried out,and the protection system of single and double row and multi faced steel pipe isolation pile is compared.For the settlement control analysis,the double row and three sides isolation pile protection scheme was first identified and applied.The settlement of the pile foundation caused by the tunnel excavation was successfully controlled.Aiming at the problem of stability of the shield tunnel face in the rich water area,by FLAC^3D simulates the stress state of the shield machine in all weathered rock layers,"upper soft and hard"and all hard rock,and establishes the stability criterion of the stability of the element state stability index of the fluid and solid coupling,and realizes the stability analysis.Aiming at the uncertainty problem of geological condition,the dynamic information management system is constructed based on the method of combining parameter identification with dynamic adjustment of construction scheme.On the basis of monitoring multiple information data,based on the three-dimensional numerical simulation,the orthogonal test scheme is designed for numerical calculation.The sensitivity analysis of the surrounding rock parameters is carried out,and the multi information joint anti analysis technology is established.The mechanical parameters of the layer are back analyzed,and the parameters of tunnel excavation support and shield tunneling are optimized.Finally,the verification,prediction and analysis are carried out with examples,which provide reference and reference for similar projects.