On The Characteristic Of Stress Transferring In Gravel Pile

Through this article we studies the pressure on the bottom changes with the pressure on the top in gravel pile though the experiment, numerical simulation and theoretical calculation. And analyze the character of stress transferring in gravel pile via the changing in pressure. From the study we get gravel pile failure model by the stress transferring modes. We obtain the following conclusions:We get the gravel pile exist a critical aspect ratio (no matter what square pile or circular pile about5) effects by three-dimensional experimental, that is a critical pile length. We also get the shape of the pile has little effect on the stress transferring mode.We get the gravel pile exist a critical aspect ratio (two-dimensional is5-7, three dimensional is about7) effects by two-dimensional and three-dimensional numerical simulation. Two-dimensional simulation get the loading form has little effect on the stress transferring mode. Three-dimensional simulation get the friction coefficient is also a factor that affects of the stress transferring model, that is greater the friction coefficient than the lower efficiency of the pressure passed down.We get the gravel pile exists a critical aspect ratio (about7) effects by three-dimensional theoretical calculation.Regardless of experiment results, numerical simulation results and theoretical calculation results we can also get the similar conclusions, that gravel pile has critical length. The length exceeds the critical length and not has different stress on transferring modes, and it also means that it has different failure models between long pile and short pile. When the pile length less than the critical length, the stress chain passed to the bottom more, the stress passed to the bottom of the pile. The failure of the short pile is induced by the pile plunging into the bottom soil. When the pile exceed of the critical length, the stress chain diffusion on both sides of the pile, the stress chain sets up the step on the soil around the pile. That is formed the arch structure in the top of the pile, support pressure, and pressure passed down less, trued to the round of pile. The failure of the long pile is caused by the shear failure in a triangle region of the lateral soil which induces the swelled failure of the top arch structure.The study shows that we must use different ways to create formulas long pile or short pile.