Dry-wet Circulation Under The Action Of Pile Soil Interface Shear Properties Research

As a kind of deep foundation structure form, pile foundations has many goodcharacteristics: high bearing capacity, small and more uniform foundation settlement,good stability and seismic behavior, it can also adapt to all kinds of complicatedgeological conditions, etc. As a result, it is widely used in engineering application. Soas to guarantee that the upper structures and buildings have enough strength andstability, and then achieve the purpose of pile foundation optimization design, theultimate bearing capacity of pile foundation and the relative displacement betweenpile and soil have to be deeply researched; the key is how to determine the interfaceshear characters between pile and soil.Nowadays, many experts and scholars have researched the interface shearcharacters problems between pile and soil at home and abroad, also made someachievements. However, they often consider the influence factors are more unilateral;also the pile-soil system theory is not perfect enough. Due to the change of the rainfallcondition, surface water infiltration or the lifting of underground water level make thesoil around pile in the dry-wet cycle environment. The soil may happens irreversiblefine structure destruction under repeated effect of dry-wet cycle, and in macro viewsome softening characteristics, will easy lead to the bearing capacity of the pilefoundation causing hidden danger. Considering the dry-wet cycle repeated effect hasimportant influence on the soil around pile, and then linking to the frictional softeningcharacteristics of pile-soil interface, this paper focuses on the change law of interfaceshear characters affected by the dry-wet cycle between single concrete pile and clay,and carries out many studies. Firstly, softening deformation mechanism of the soilaround pile is researched by direct shear apparatus in this paper. Then, using thehomemade pile-soil interface shear characters test device, simulated pile-soil interfaceshear and slip process under the action of dry-wet cycle, and deals with the test data toanalysis the related law. Secondly, theory of the pile-soil system load transfer andcalculation model are studied via the load transfer analysis method. Finally, based onthe pile-soil interface shear test results, the curves between the performance of theultimate interface traction and the soil depth in the role of dry-wet cycle is discussed,and combined with the pile foundation engineering example tests data, distribution ofthe side friction of pile is further analyzed.