Study Of The Uplift Capacity And Deformation Of Tension Piles

With the development of municipal engineering, lots of underground structuresare built. More and more researchers are aware of the importance of resisting theuplift load. Tension piles are widely used to resist the uplift load, but theories abouttension piles are far behind of engineering practice. This paper mainly study ultimatebearing capacity and displacement of tension piles, gained some beneficial conclusion.The studies of the thesis consist of the follow contents:1. The paper gived the methods to predict the ultimate bearing capacity of single andgroup tension pile. The methods of analyzing the ultimate bearing capacity ofgroup tension pile can involve the effect of the interactive of pile and soil.2. The paper gives the methods to predict the displacement of tension piles andunder-reamed piles. The relation between uplift load and elastic displacement isdiscussed. Moreover, the non- linear displacement of tension piles can beachieved with the method of assort with deformation.3. It is impossible that the Q-s curves in the different actual engineering are the same.The parameters are selected to change the different curves to the single curve.The single curve is modeled by the regression formula. We can use the formulato predict the displacement of tension piles.4. The displacement of tension pile can be analyzed by the modified variationalapproach, the paper presents a simply approach so that the deformation oftension pile groups can be solved by calculating a 2×2 array.5. The paper applies the P-s curves to the analysis of the displacement of grouptension piles. Piles are modeled as interacting nonlinear springs. The nonlinearbehaviour of pile-soil interaction can be matched by the hyperbola function. Theinteraction between piles is analyzed by interaction factors.6. Based on the theory of equivalent pier, the nonlinear displacement of tension pilescan be deduced. The equivalent pier with surrounding soil by means of thehyperbola function is considered. The load-displacement response of the equivalent pier can be calculated using solutions for the response of single pile,but to take into account the group action due to pile-pile interaction.