Based on the results of static load test in-suit

a formulas for characteristic value of bearing capacity in cement-soil long-short piles composite foundation has been deduced in this paper.According to the dispalcement relationship of piles

soil and foundation

then

a method has been achieved after studing bearing mobilization coefficient of surgrade and suitable s/b for characteristic value of bearing capacity of single-pile composite foundation and long-short piles composite foundation.It has been revealed that pile will be destoried firstly before soil in long-short composite foundation is destoried.The s/b where pile is destoried is the upper limit for characteristic value of bearing capacity of composite foundation.The upper limit of s/b is 0.003 4 and the bearing mobilization coefficient of soil is 0.29 in composite foundtion when Ec is 100 MPa.