Analysis Of Influence Of Lanzhou Subway Shield Tunnel Construction On Adjacent Buildings

Permitted to be constructed in the near future Lanzhou Metro Line1should adapt theshield construction due to the intensive buildings and utilities, increasingly complextraffic,and the range of the tunnel is located in the sandy loess and coarse round gravel soilbased, however shield construction is still inevitably has a disturbance impact on thesurrounding soil and buildings. Therefore combined with specific engineering practice tostudy the impact of subway construction on surrounding environment has great practicalsignificance for reasonable arrangements of subway construction, shield design and protectionof environment.This article relies on the planning and construction of the Lanzhou subwayproject, analyzes the disturbance of Shield Tunneling Method in subway constructionproducing on adjacent buildings. During the analysis, a three-dimensional finite elementmodel considering the buildings as well as shield construction process is established.The ruleof surface deformation,foundation settlement,the force of buildings and the stress of shieldtunnel segment is emphatically studied under the conditions that the adjacent buildings are ofdifferent distance from tunnel axis.Some meaningful conclusions are obtained in the study;the following aspects of the work are undertaken in this paper:1) Summarize and sort out the researches of related fields, analyze the influencingfactors and mechanism of surface settlement caused by shield construction, and calculationformula of soil deformation caused by the main factors is deduced.2) Introduce some basic theory on Finite Element, shield excavation as well as soilconstitutive relation, give a detailed description on how to use numerical simulation methodsto achieve the dynamic simulation of shield excavation.3) Establish a three-dimensional model considering the buildings as well as shieldconstruction process by numerical software ANSYS for specific engineering. Make a detailedintroduction to the entire modeling process, including the calculation of the size of the modeland the determination of parameters as well as the simulation steps of the constructionprocess.4) During the simulation and calculation, the ground settlement with shield tunnel wasstudied in this paper and the case of injection pressure and the thrust of tunnel face was alsoconsidered.The foundation settlement of buildings and force acted on buildings are mainlystudied under the conditions that the buildings are of different distance from tunnel axis (L/D),besides, stress acted on tunnel segment are also studied under the conditions that he buildingsare of different distance. Through the corresponding analytical research work, somemeaningful conclusions are drawn.5) Give an introduction on the protection level of the existing buildings, as well as theallowable surface settlement based on the foundation settlement control, and finally aiming at Lanzhou Metro Line1, put forward some control measures on how to reduce the impact ofshield construction on buildings.6) Make the prospects for further work. Besides, the results obtained in the papers can beused as a reference for similar engineering.