Study On Safety Evaluation Of Adjacent Masonary Building Influenced By Shield Construction In Taiyuan Subway

In the 21st century,with the development of rail transit in China,subway has become the first choice for major cities to develop green transportation.It is inevitable that the construction of subway section tunnels will cause damage to them.In order to ensure the normal construction of the tunnel and minimize building damage,it is important to evaluate the safety of the subway tunnel section to pass through the building at a short distance and to formulate a unified deformation control standard.Realistic meaning.In this paper,relying on the typical project of super-close side-crossing brick-concrete structure in the first phase of the double-large section double-line tunnel of Taiyuan Rail Transit Line 2,using theoretical and empirical analysis,on-site measurement and numerical simulation,etc.,the subway section tunnel crosses the existing tunnel.Core issues such as the basic theory of the safety assessment of brick-concrete structures,the content of the assessment,the determination of deformation control indicators and standards are discussed in depth,and the main research results are as follows:（1）Explain the method and basis for evaluating the safety status of the tunnel adjacent to the building,emphasizing the importance of the current status of building components and material performance testing and foundation safety rating.The evaluation of each unit should be strictly in accordance with the "Civil Building Reliability Appraisal Standard"（GB50292-2015）and "Code for Design of Building Foundations"（GB50007-2011）and other standards and specifications.（2）Propose the procedures,contents and methods for the safety assessment of buildings in the neighborhood of shield construction: understand the environment of the new tunnel project and the profile of existing buildings in the neighborhood;investigate,detect and appraise the current state of building safety Evaluate and determine the remaining allowable deformation of the building;use Midas/GTS to establish a three-dimensional simulation model to predict the additional deformation that may be caused by the subway tunnel passing through the adjacent building,compare it with the remaining allowable deformation,find the balance between the two,and finally give the evaluation conclusion and Suggest.（3）Combining the special geological conditions of Taiyuan area,analyzing the mechanical mechanism and time-space relationship of brick-concrete structure failure,and comparing and discussing related documents and local data,it is concluded that the subway deformation control indicators in Taiyuan area are: maximum settlement and differential settlement.;It is recommended that the ideal area for the maximum allowable surface settlement of the Taiyuan subway shield construction without adjacent buildings is 30-37mm;when there is an adjacent brick-concrete structure,the ideal area for the maximum allowable surface settlement is 20-30 mm,and the settlement difference is 5-11 mm.（4）A detailed safety assessment was carried out on the family building of the public transportation company in the double-large section of Taiyuan Metro Line 2.The deformation of the attachment of the brick-concrete structure during the tunnel construction was simulated by Midas/GTS to be 41.2mm.Numerical simulation of grouting reinforcement is carried out in the project.The reinforcement area is 2m around the foundation and within 2m below the foundation.The results show that the additional deformation of the building during the construction period is 23.9mm,the actual measurement is 25 mm on site,and the effect is good.