Analysis on Deformation and Stability of Circular Pipe-jacking Shaft Foundation Pit Based on Strength Reduction Method
The design method of circular pie-jacking shaft foundation pit is the plane elastic fulcrum method in the current specification.Considering the arch effect of supporting structure of ring foundation pit and the soil arch effect of surrounding soil body under 3D space,the result of plane calculation is more conservative than the actual one.Therefore,based on the strength reduction method,the 2D and 3D finite element models of ring pipe-jacking shaft foundation pit are established to obtain the safety coefficient and deformation of foundation pit The computed result is analysed and compared with the standard method.The analysis shows that when the depth to diameter ratio h/r was larger than 0.9,the soil at the bottom of the pit is uplifted to deform When the depth to diameter ratio h/r is less than 0.9 and gradually decreases,the circular sliding surface appears at the bottom of pit.The soil failure is in the overall sliding mode.Under 3D model,the arch effect of building envelope will obstruct the influence of the pit-side overload on the distribution of the circular sliding surface The soil arch effect of the surrounding soil reduces the ground settlement and the envelope deformation The safety factor of foundation pit based on strength reduction method is 2～3 times of the anti-uplift safety factors at the pit bottom in the standard method.
circular pipe-jacking shaft foundation pitstrength reduction methodstability analysisfinite element analysisdepth to diameter ratio
NETL
NSTL
万方数据
