Theoretical And Experimental Researches Of Pile Foundation Self-anchored Static Loading Test Technology

As a new technology, pile foundation self-anchored static loading test technology that was based on under-pile anchoring technology, whose design theories and experiment analysis were still in blank currently. Integrating with trasportation technology project of Hunan province (No. 200609), sufficient researches and analysis about pile foundation self-anchored static loading test technology was done in this thesis in order to improve and develop such technology. Main contents were listed as following:Firstly, pile properties under vertical loading were thoroughly analyzed and calculated. By building multi-broken line model that on conditions of pile-surrounding soil settlement was considered, and integrating pile energy finite difference equation that was based on energy principle, pile properties calculation program was compiled. Then, load coordination method and minimum potential energy coordination method, as well as their corresponding convergence procedure were proposed. At the same time, when settlement of pile-surrounding soil caused pile negative friction, pile properties numerical caculation method was presented. Also, pile properties under vertical loading were calculated basing on a specific project.Secondily, under-pile anchor properties in self-anchored static loading test were deeply analyzed and calculated. Starting from load transfer method, using anchorage body energy finite difference equation, and basing on a specific project, tensile anchor and pressure type anchor were studied respectively. Furthermore, P-s curve of pressure-dispersive anchor bearing unit properties was calculated. Then, properites of pressure-dispersive anchor under different stretching procedures could be obtained.Thirdly, as key medium between pile and anchor in pile foundation self-anchoring static loading test, its theory deduction and calculation method of solving displacement was given. Basing on earth pressure calculation under different conditions, sheering stress in various depth and deformation was also brought out. According to energy principle, soil energy finite difference equation as well as soil displacement calculation programme in a finite sapce were proposed. Through analyzing influencing factors on soil displacement, helpful quantitative conclusions for practical projects could be obtained.Furthremore, calculation metheod of pile properties in self-anchored static loading test were developed, which was based on theories and program implementation methods of pile, anchor and soil. Combining with a calculating example, settlement influencing factors on pile foundation in self-anchored test system were also analyzed. Meanwhile, through data analysis, inverse analysis methods of loading transfer between pile and soil in self-anchored test system, as well as data conversion method from self-anchored static loading test to gereral static loading test, were established.For further exploring working mechanism of pile foundation self-anchored static loading test, and interactions among pile, soil and anchor, a specific laboratory model test was introduced in detail, and its model data were also sorted and analyzed.Finally, all data from laboratory model test were thoroughly analyzed for verification. Above all, through analyzing model pile data, efficiency of loading transfer model and accuracy of pile properties calculation program was evaluated. Subsequently, basing on loading transfer behavior of model anchor, dynamic broken line model was established. By comparing with testing data, accuracy of anchor calculation program of dynamic broken line model and pile calculation program in self-anchored test was measured. According to inverse analysis method of loading transfer between pile and soil in self-anchored test, its model pile testing data were analyzed. Through comparing with testing data on the same conditions, feasibility and accuracy of data conversion method from self-anchored static loading test to gereral static loading test was also verified.