The Test Study On The Loading Transfer Mechanism Of Model Piles With Branches And Plates

There were three different model piles named model pile of NO. 1, model pile of NO.2 (with one branch), model of NO.3 (with two branches). Four model tests had been designed. Firstly, three model tests had been practiced, six times circulating loading tests to every pile including four times repeated and fast circulating loading tests in unsaturated silt. The last model test had been practiced in saturated silt, six times circulating loading tests to NO.3 pile including four times repeated and fast circulating loading tests. By studying the data from different model pile tests to testify that the project performance of piles with branches and its loading transfer mechanism are different from common piles, the pressure of model pile had changed suddenly near the branches. Pile with branches and plates sufficiently increases the bearing of the two plates, and the load at the end of the pile is small, so the total bearing capacity of the pile with branches and plates could be advanced. Meanwhile, its settlement is very small. After four times repeated and fast circulating loading tests, the total settlement of the pile with branches and plates are smaller than the common piles, so that under repeated and fast load pile with branches and plates are better than common pile in stability. The compaction of the silt had been enhanced after five times circulating loading tests, consolidated silt has larger capacity while its deformation is small, so pile with branches and plates could bear higher load in the sixth time test. The compaction of silt has direct ratio with its water content. By comparing the third with the last model test, it was proved that the project performance pile with branches and plates had in saturated silt is advanced than in saturated silt, in addition, it was also proved that the pile with branched and plates is much more suitable for the soil which has high compaction. But no matter in unsaturated or saturated silt, it was showed that there were relationship between every part of the total bearing capacity of the pile with branches and plates, especially the complex relationship between the bearing of the upper plate and the skin friction of the silt. So the total bearing capacity of the pile with branches and plates is not the simple amount of the ultimate bearing capacity of each part, coefficients should be introduced to consider the relationship mentioned above, besides, a rational distance between two plates is important to the performance of pile with branches and plates. In addition to the change of the loading transfer mechanism, the area of the stress in silt had changed so in the practice, a suitable distance should be settled between two piles to consider the efficiency of pile groups.