| Calculation of uplift resistance of foundation pit is an important part of the foundation engineering design,especially for deep excavation in soft soil is very important.The bottom heave stability analysis method can not fully consider many factors affecting pit stability,analysis method in practical engineering application is not flexible,reduce the accuracy of the evaluation results of the basal heave stability.In this paper,Considering the reinforcement effect on heave supporting engineering of pile and soil in the passive area,based on the present situation of the research on the stability analysis of foundation pit at home and abroad.The calculation method of excavation against heave stability to carry out further research.The main work includes the following aspects:(1)Research status analysis of basal heave stability analysis,the mechanism and main factors of foundation pit heave destruction,The calculation formula of deficiency ofsafety coefficient recommended by the proposed classical calculation method and the current standard,the influence of the depth of the support structure and the soil reinforcement in the passive zone on the stability of the foundation pit is not considered.(2)The analysis method of bearing capacity of foundation pit based on limit analysis,the failure mechanism of foundation pit,bracing engineering pile depth consideration,put forward safety factor of foundation pit stability calculation formula.This can be considered supporting engineering pile's stiffness and strength,different depth of soil effective stress changes,retaining wall and soil friction,the soil behind the wall vertical shear resistance of the factors such as uplift of the favorable effect.(3)Combined with an example,the influence of different factors on the stability safety factor is analyzed,The supporting pile's stiffness and strength,different depth of soil effective stress changes,retaining wall and soil friction,the vertical shear wall soil after considering factors such as formula,the result is more reasonable,safe,applicable,to a certain extent verified the applicability this paper chooses the method of modifying.(4)Based on the analysis method of circular arc sliding resistance of foundation pit,considering the influence of soil reinforcement in passive zone,the calculation formula of safety factor.(5)Combined with example,further analysis of reinforced soil section against influence of heave stability safety coefficient,the results showed that the reinforcement of soil around pile bottom supporting engineering over the sliding surface in the case of resistant heave stability safety coefficient increases obviously,on this basis,considering the economy,further put forward the variable cross-section pit soil reinforcement method. |
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