Study On Settlement Standard And Construction Measures Of Shield

With the development of China’s society and economy,the degree of urban modernization construction has been continuously improved,and the development and utilization of urban underground space has gradually become the key development direction of urban construction.As the main aspect of the construction of underground engineering,subway not only relieves the pressure of urban traffic,but also improves the utilization of urban space.However,it brings the negative impact of the environment.With the excavation of the subway tunnel,the deformation and stress redistribution of the strata leads to the uneven settlement of the surface,which has caused some disturbance to the surrounding environment.Especially for the existing buildings,often small deformation and settlement will bring greater harm,and then affect the safety,stability and the use of function of the structure.Therefore,it is very important to study the influence and control of shield construction of urben metro on the surface buildings.This paper,based on the investigation of the relevant domestic at home and abroad,which through theoretical analysis and finite element simulation,taking the shield tunnel adjacent wear the surface buildings for Shijiazhuang Metro Line 3project section as the project example.This paper studies the structure safety and the settlement control standard of the shield tunneling adjacent wear the existing building.The main contents include:(1)According to the characteristics of shield tunneling method,this paper analyzes the reasons,mechanism and development process of the stratum settlement caused by metro shield construction,discusses the influencing factors of the shield tunnel adjacent wear under the building,and contrasts the displacement of soil under the condition of natural ground and existing buildings.(2)In this paper,the main failure modes and deformation features of building structures are described,and the deformation and internal force of the structure are analyzed.Based on the frame structure,masonry structure,steel structure of the threekinds of typical structure as an example,their characteristics of sedimentation failure and resistance to deformation are analyzed,and the criterion of structural damage is studied.(3)In order to put forward the most non parameter condition of the settlement control of the building,this paper studies the sensitivity of the parameters,such as the depth of the tunnel,the diameter of the tunnel,the location of the tunnel and the buildings and so on.(4)With the shield tunnel construction on the analysis of building deformation and stress,in this paper,the maximum absolute settlement and the maximum differential settlement are the main control objectives,and the settlement rate and the crack width are the auxiliary control targets,to determine the structural stability of the deformation control indicators and construction safeguards.At the same time the practical engineering case analysis of Huaianqiao-Xisanjiao interval for Shijiazhuang Metro Line 3 verify and perfect this view.On the basis of the above research results,the appraisal system of shield construction to the control standard for building settlement is established,which is expected to be applied in the practical engineering of Shijiazhuang metro tunnel adjacent wear the building.