Model And Computational Method For Interaction Between Passive Piles And Surrounding Soil

Studied the interaction between passive piles and surrounding soil, aiming at an approximate method based upon a more clearly understanding for the mechanism of passive piles. Adopted arching effects and correlated production, as well as theories addressing the problem. Concerning that analysis relies heavily upon the model for interaction between passive piles and soil, firstly analyzed the validities of the generally used models. Abstracted five classes of assumptions that frequently employed to simplify the situation for modeling. These assumptions, including calculating boundary, contact mechanism, the simplification of plane strain, initial weight stress and pile rigidity assumption, were evaluated for their influences on the computational results for passive piles. Started this evaluation with a familiar model for the analysis for arching effects between passive piles, using Finite Element Method(FEM) to study the principle of load transfer within the surrounding soil. Based on the foregoing studies, as well as data from one experiment for "trap door" by other researchers, discussed the definition of arching effects, which already used and treated as load transfer around passive piles or interaction between passive piles and surrounding soil herein. Furthermore, five kinds of methods to simulate the normal contact and Coulomb friction were cited, and results from FEM simulations were compared to assess their rationalities. After that, plane strain, with magnitude of its error, as a wildly referred assumption within pile-soil interaction was also discussed with the help of FEM. Upon the base of the three above-mentioned studies on assumptions relating to two-dimensional model, obtained an approximate method for calculating ultimate lateral force for passive piles. By extending and modifying a wildly referred theory of plastic deformation, educed a new method. Then proved its result to be in considerably agreement with the original one, plus more rigorous method in point. For practical application, additionally discussed the pile spacing, taking into account the assumptions for educing. Eventually imported three-dimensional model to study the other two assumptions, that is pile rigidity and initial stress. Suggested several affects resulted from three-dimensional model, which may be failed to be considered in plane stain model. In addition, made suggestion for formly proposed method while considering the fact that not all parts of soil mass enter plastic ultimate state at the same time indicating soil failure, and other subordinate effects. Proposed mobilized factors for some given operation conditions based on simulation results. Provided an equation for pile-reinforced slope when taking into account the passive piles for practical use.