Research On Reinforcing Soil Foundation Of The Existing Railway Field With A Shield Tunnel Under-acrossing

With the development of subway construction, tunnel's influence on surrounding environment is paid more and more attention to. To prevent shield-driven tunnel across existing railway affecting the safety of trains, reinforcement of existing railway becomes an important issue.Combined with the tunnel project located in tunnel section Honghuayan Station～Railway North Station～Renmin North Road in Chengdu, this paper analyzes the reinforcing effects of composite foundation when shield-driven tunnel across below and tries to find the regularity in soil foundation improvement under such conditions.The paper compares modified Peck settlement curve and numerical calculation curve with practically measured data, finds suitable parameters, and establishes piles-soil separation model and equivalent solid model using software FLAC in a finite difference way. In addition, research on influence of effective pile length, effective plate thickness, effective displacement ratio and train loads is carried out, based on which influencing regulation of pile length, plate thickness and displacement ratio on ground deformation under the condition of shield-driver tunnel excavation is analyzed. Moreover this can offer reference for similar projects to a certain extent.