Influence factor analysis of load-bearing character of long-short piles for composite foundation

By using the finite element software ABAQUS,the effects and laws of cushion modulus,cushion thickness,short pile modulus,pressure of cap-padding on the stress ratio of long pile to soil,short pile to soil,long pile to short pile,settlement of cap are analysed respectively.Numerical analysis results indicate: The existence of cushion increases the settlement of foundation,so as to adjust the assignment stress between piles and soils.Pile body stress of long pile is increased;while that of short pile is fallen with the increasement of cushion modulus.Settlement of composite foundation is decreased with the increase of short pile rigidity.The stress ratio of pile to soil and difference of displacement are raised with the increasement of load on the top of foundation.Based on the in-situ measurement of pressures by static loading tests of a practical engineering in Wuhan,load mechanics of long pile and soil,short pile and soil,long-short piles are analyzed.The numerical analysis results and in-situ tests will provide references for future design and construction of this kind of composite foundation.