Analysis On Compacting Effect Of Pipe Piles Based On Structure Damage Of Soil

Pile sinking in soft soils causes a lot of problems such as disturbance and damage of soils which change engineering properties of soils. Due to such problems and the widely application of pipe piles, researches on the compaction effects of them become an important and urgent issue. It has both theoretical and practical values. Based on the previous researches of compaction effects, the concept of structure damages in soft soils is introduced to cylindrical cavity expansion theory and mechanism research of c ompaction effects o f pi pe piles based on t he c oncept o f s tructure da mage is conducted in this paper.Firstly, th e a pplication superiority of p ipe p iles and t heir e nvironmental influences during pile sinking is discussed and the important value of the solution to this issue is proposed. The previous researches on compaction effects are reviewed and the basic methods of traditional cylindrical cavity expansion theory are introduced. Based on that, the concept of structure damage in soft soils is brought into this paper. The calculation and analysis methods of modified cylindrical cavity expansion theory to solve this problem are proposed. And the rationality of these methods is explained.Secondly, according to different situations of stress and strain, the soils around piles are divided into different districts. The field of stress, strain and displacement, ultimate expansion p ressure a nd ul timate expansion r adius are s olved i n use of three-fold-line strain softening model and four-fold-line strain softening model. Based on that, the influence by different parameters to the pressure and radius are analyzed.Thirdly, c ombining a s pecific e ngineering case, t he p ore water pressure a nd lateral displacement are monitored and their laws are analyzed. Aimed at this problem, the measures in design and construction are given to reduce the compaction effects.Both t est a nd t heoretical methods a re a pplied in this pa per i n w hich the mechanism analysis i s conducted based on the concept of structure damage. The solution of cylindrical cavity expansion theory in soft soils is given and comparative analysis of different parameters is conducted. By research and analysis of a specific engineering case, t he measures t o r educe the c ompaction e ffects a re given. The research results can be applied in soft soils as a meaningful reference.