Study on Time Effect of Bearing Characteristics of XCC Rigid Pile Composite Foundation in Soft Soil
XCC rigid pile composite foundation is a new type of rigid pile composite foundation developed to deal with soft soil foundation.Compared with the traditional rigid pile composite foundation,it has the advantages of high bearing capacity and good economic benefits.But at present,most studies have not considered the influence of pile,soil and cushion changing with time.In order to solve this problem,the model test of bearing time of XCC rieid pile composite foundation in soft soil was carried out,with emphasis on measuring and analyzing the variation law of surface settlement,excess pore pressure dissipation,vertical earth pressure distribution of embankment,grid strain,pile-soil stress ratio and pile axial force with time,and analyzed the difference of test results between XCC rigid pile and circular rigid pile composite foundation under different pile arrangement.The results show that the section shape and pile arrangement have no effect on the consolidation rate of rigid piles,while XCC rigid piles and plum blossom shaped piles reduce the settlement depth;after the load is applied,the vertical earth pressure of embankment of different rigid pile composite foundation sharply increases to the maximum,then gradually decreases with time and tends to a stable value,and the soil arch height gradually increases with the increase of time and load and then tends to be stable.Under the same conditions,the soil pressure at the top of XCC rigid pile are larger than those of circular pile,the soil pressure of plum blossom shaped pile are slightly smaller than that of rectangular pile,the strain of grid above pile top is obviously larger than that of soil between piles,and the strain growth rate decreases gradually with time,and the grid strain of XCC rigid pile and rectangular fabric piles pile is relatively larger.The variation curves of pile-soil stress ratio with time and load of different types of rigid pile composite foundation increase at first and then decrease and tend to be stable,and the pile-soil stress ratio of XCC rigid pile is about 25％higher than that of circular pile.The axial force of rigid pile gradually increases with time until stable,and with the increase of time,the pile side friction increases gradually,and the position of neutral point gradually moves down.
subgrade engineeringrigid pile composite foundationscale model testtimelinesssoil arch effect
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