Analysis Of Single Pile Stress State In Permafrost Region

About 1/4 area of world land is permafrost, the distribution of permafrost in our country is also extensive, up to 2.15 million square kilometers. So we can't avoid building foundation in the permafrost region in order to construct the roads, bridges, irrigation works, municipal works, and so on. At the same time, the existent construction has already be effected. Accordingly, bridge substructures in the permafrost area are usually influenced by the abominable environment. Traffic transport in permafrost area is also seriously influenced by the deformed bridges, its serious desease problem demands us to solve urgently. So, analysing the stress state of single pile foundation in permafrost area has realistic meanings. The thesis presents the properties of the single pile and the frozen soil, the constitutive behavior of the frozen soil, the permafrost engineering characteristic, single pile load transfer and single pile destruct pattern, then, the interaction mechanism, and the stress distributing are introduced in detail. On the basis of the finite element theory and contact theory, by using the large-scale finite element software ANSYS, the thesis accomplishes the simulation of the testing pile using the Willam-Warnke destruction criterion for concrete and the Drucker-Prager yield criterion for frozen soil. It simulates the reinforced concrete by Solid 65 element, using the D-P material for frozen soil. The result of finite element model created by ANSYS which is verified by the single pile experiment in Kun-Lun Mountain permafrost zone confirms the feasibility to the model of pile and frozen soil. Subsequently, this thesis mainly consummates the analysis of the stress state by the stress contour of pile and soil, the datasheete and the correlative graph, and it analyses the effect of the parameter of contact element in ANSYS. These parameters include the elastic modulus, the diameter of the pile, and the distribution of the soil around the pile. The research result has important reference value to pile foundation design in permafrost area.