Study On Excavation Deformation Characteristics Of Deep Foundation Pit In Soft Soil

When the foundation pit project is carried out in the soft soil area,attention must be paid to the deformation of the foundation pit and changes in the surrounding structures,municipal pipelines,and the surrounding ground surface settlement.Therefore,it is necessary to predict the possible unfavorable deformation of the foundation pit before excavation.On the one hand,it can be used as a reference for the foundation pit support design;on the other hand,it can be pointed out that unsafe factors and locations in the construction of layered excavation in foundation pits.The paper uses the method of numerical simulation combined with field measurement results.Taking the soft foundation deep foundation pit project of Wuhan China Nuclear Times Square as the engineering background,the deformation characteristics of deep foundation excavation in soft soil are analyzed and summarized.The main research contents are as follows:(1)According to the geological survey data,the engineering characteristics,surrounding environment and support structure selection of the deep foundation pit in Wuhan Nuclear Times Square were analyzed,and the calculation method for deep foundation pit deformation was discussed.(2)The author selects the typical profile of deep foundation pit in soft soil,uses the modified Cambridge model,establishes a two-dimensional model,makes a prediction of the excavation deformation of the foundation pit without internal support,and analyzes the simulation results.(3)The author analyzes the deep soil horizontal displacement of deep foundation pit in soft soil,the stress of supporting steel bars in foundation pits,the horizontal displacement and settlement of locking beams,the settlement of pillar piles,the settlement of surrounding ground,the settlement of surrounding soil,and settlement varied with the excavation process of pipelines.(4)A three-dimensional numerical model is established based on the supporting structure and the depth of excavation of the support + cast-in-place pile in the foundation pit,and the simulation results are analyzed.Then,comparing the two-dimensional simulation results,on-site monitoring data and three-dimensional simulation results,the deformation characteristics of deep foundation pit excavation in soft soil are analyzed.