Study On Disturbance Dffect And Control Of Shield Tunneling In Taiyuan Subway Tunnel

Urban subway tunnel shield construction on the surrounding soil disturbance caused in the process of strata displacement deformation,the movement of the strata in building foundation will produce additional internal force and deformation,leading to uneven settlement,tilt or structure damage,etc.,so the key research of shield construction on the surrounding soil and the structure of the impact mechanism,optimization of construction parameters and strengthening protection of adjacent buildings has important significance.Based on the engineering background of the double-large section shield tunneling in taiyuan metro line 2,this paper studies the disturbance effect of shield tunneling on buildings with different foundation forms by combining numerical simulation and field study,and proposes appropriate control methods.Combined with the engineering practical conditions in the region model,according to its basic building at the same time be divided into two types of deep and shallow foundation,pile raft foundation and separately represented and raft foundation is simulated research,the results show that the side wear of shield raft foundation building,whole building subsidence and tilt rate in decreases with the increase of side wear space,but because the engineering properties of miscellaneous fill soil bad aggravated soil and buildings,the disturbance effect of excavation unloading of overlying soil subsidence caused by explosion.With the continuous increase of the overlying soil thickNess,the scope of influence of shield tunneling is expanding,from the original one time of the outer diameter of the tunnel to about three times of the outer diameter,and when the horizontal spacing is the same,the building tilting rate increases gradually.Wear the pile raft foundation in shield side buildings,when the foundation pile length is divided into three kinds of circumstances,disturbance were not destroy the stability of the pile-supported raft foundation,and under the influence of disturbances in the construction,the building foundation,foundation subsidence and tilt rate of tunnel in the overlying soil subsidence several indicators,building subsidence and tilt are within the specification requirements,but the surface settlement and pile position shift,compared to the three largest long pile foundation;For side wear long pile foundation structure,level spacing and thickNess of covering two factors,along with the horizontal distance between the direction of increasing the overall level of building tilt rate but increase amplitude is small,the largest tilt rate is still within the specification requirements,the overlying soil and tunnel is affected by the weight of building subsidence decrease gradually,and in the process of covering thickNess increasing building tilt rate at 0.5 ‰ or so change,conform to the requirements of the specification,the surface subsidence increases gradually,the tunnel between the building and the subsidence of soil increased obviously.The double-large section raft foundation building was selected as the research object,and the shield tunneling parameters and partition method were studied in the control measures.It was considered that the shield tunneling parameters alone could not achieve the purpose of strengthening and protecting the adjacent buildings.Partition method for isolation of pile are studied,using the orthogonal experiment method to isolate setting position of the pile,pile length and pile spacing three factors were analyzed,and the various factors on the most foundation subsidence and tilt rate of the two indicators,the influence of the parameters of the isolation pile design optimization,and study the reinforcement effect of the isolation piles on the soil.