Foundation Pit Monitoring And Numerical Simuiatiun Analysis For Jinjiang Station Of Chengdu Metro

Thesis combine One line of Chengdu metro specific project，, based on Study ofthe deep foundation ditch engineering both at home and abroad, make acomprehensive summarize of the present research situation of deformation control ofdeep foundation pit engineering,. and points out the basic law that more attentionshould be paid on horizontal displacement deformation when mining enclosure walland surface subsidence deformation after mining diaphragm wall during explore thelaw of deformation in Foundation Pit engineeringIt also introduces the design calculation theory of supporting structure offoundation pit, analyzes the advantages, disadvantages and applicability of variouscalculation methods, expounds the application of numerical simulation in foundationpit engineering, and gives a simple introduction to space-time effect principle and thetheory of inverse analysis. At last, this paper summarizes the characteristics of soilconsolidation coursed by precipitation，and describes basic equation and definiteconditions of seepage, deduces coupling equation of seepage field and stress fieldduring foundation pit dewatering according to finite-difference theory, calculationsteps of coupling analysis are also summarized.Based on long-term construction monitoring to the excavation of ChengduMetro Line1，and analyzing and dealing with the data on pile body horizontal shift,ground settlement, building settlement, horizontal displacements of the pile tops andthe axial force of steel prop through field observation, the deformation law ofenclosure structure and soil around deep excavation in the process of construction，aswell as the accumulative value and developing rate of these deformation was obtained.meanwhile, combined with construction condition of Chengdu area，analyzes thecause of larger displacement and ground Settlement of individual retaining pile，and discusses the measures for the foundation pit deformation control in metroconstruction，offers technical support for Chengdu metro construction.The study models respectively two simulated excavation process building by using finite difference software FLAC3D，and calculates considering two conditionsrespectively of precipitation consolidation effect or not，simulates excavation process，simulates the enclosure structure and the construction procedure in actual engineering，simulates site actual process of dewatering in excavation，analyzes seepage fieldcoupled with stress field，then the numerical calculation of excavation was carried outwhich gives a comprehensive consideration of excavation and precipitation as wellas other influencing soil strength and supporting structure stability factors. and finallygets the stress, deformation nephogram and eminence status of enclosure structureand soil under the different status of two models. By comparing to the measuredvalue，the degeneration law of enclosure structure and soil can be obtained，numericalsimulation calculation considering precipitation consolidation effect is more accordswith practical monitored results, dewatering construction is more helpful toimproving stability of foundation pit support structure.