Stability Analysis Of Deep Excavation Based On Lighting Building In Chengde City

In Chengde area, water table is shallow, gravel bed is the main aquiferous layer and its penetrability coefficient is comparatively large, settlement radius caused by dewatering is large as well. The excavation process, the supporting processes and waterproof wall of the impact on the seepage field are being analyzed through the model of foundation pit which is established by numerical simulation method. Take Lighting Building in Chengde City an instance, the stress field and seepage field are analyzed respectively by SIGMA/W module and SEEP/W module of Geo-Studio software.Supporting method and water-control method are established on conditions of geology and hydrogeology with engineering investigation in the early stage. Mechanical parameters of supporting structure are calculated and ensured according to correlative national standardized document. Based on prophase data preparation with considering primary stress,soil constitutive model and load change in excavation process, finite element model is established by using of an eight-node isoparametric element. Then, on the basis of the model above, diagram of horizontal displacement and vertical displacement on pit wall and base is concluded and the deformation law is analyzed by diagram. Soil movements will cause supporting structure changes in stress state, meanwhile they are analyzed according to deformation curve of piles and anchor.Finite element model with seepage is established by two-dimensional seepage finite element theory, and it shows the effect of waterproof wall's change by modeling seepage field when waterproof wall is at different depths of base.Deformation of pit location and working conditions of supporting structure have been concluded by modeling stress field and seepage field, then the reliability of design result is confirmed.