Research on model tests of bearing capacities for composite pile foundation under static and cyclic loading in sand

With the wide application of pile foundation,there are more and more researches on the bearing mechanism between the pile and soil.According to the contact between pile and soil,a large proportional pile-soil model test was adopted,and in order to simulate the friction effect of pile and soil better,the pile material was improved in the test,and a set of loading and measuring apparatuses were developed to adapt the vertical static and cyclic loading.The tests of vertical static and cyclic loading were taken on the composite pile foundation in sand,and the pile top settlement,the axial force and lateral friction resistance of pile,pile bottom reaction force were analyzed.The experimental results show that the pile performances are enhanced with the increasing of the loading numbers:the pile top settlement being improved by 29.6%,the axial force being improved by 40.4%,lateral friction resistance being decreased,pile bottom reaction force being increased by 50%,and the pile ultimate bearing capacity being increased by 25%,which provides a reference for the study of interaction between pile and soil under different loading conditions for the serviced pile foundation in the future.