Study On Calculating Single Pile's Bearing Capacity Considering Piles' Compaction Effect

In current foundation-designing theories, pile groups'compaction effect is rarely incorporated. As a result, single piles'bearing capacity differs sharply with the engineering data of static test or dynamic test frequently. How to calculate the effect of pile groups accurately, so as to create a more reasonable and sound theory, has become one of serious problems both in engineering and academia.At first, in this thesis, cavity expansion theory is introduced. Unified analytical solutions of cylindrical and spherical cavity expansion problems are proposed. The formulas of excess pore water pressure are thus gained.Secondly, according to the coordination of the void ratio of soil, a method is suggested in which pile groups'compaction effect can be studied by a hypothetical round-section-pile. Hypothetical radius is derived through combining the cavity expansion theory, elastic theory and Biot theory. Then the stress field and strength index of the soil in hypothetical radius are deduced. Take these as known numbers of the soil, pile groups'compaction effect can be carefully examined. The critical state is also evaluated, in the case of whether the pile groups'compaction effect is obviously present or not.Furthermore, based on the above equivalent analysis, a method of calculating single pile's bearing capacity is obtained. After that, by multiple experimental instances, the feasibility of the above-mentioned thoughts is substantiated.In the last section, following the research on pile group's compaction effects, we derived the formulas for calculating supplementary pile's bearing capacity, in which pile groups'compaction effect and supplementary pile's compaction effect are jointly considered. As the ending part, by an engineering experiment instance, the validity of this approach is strictly established.