On The Characteristic Of Stress Transferring In Stone Column By Experiment And Theory Analysis

This thesis studies the characters of the stress transferring in stone column composite foundation through experiments. Then the experiment results are analyzed by using the theory of mechanics of granular media. Finally, a 2-D model which describes the characters of the stress transferring in stone column composite foundation is built.We design the experiment equipments by ourselves, and carry out a series of experiments in laboratory. We combine the stone column research with the mechanics theory of granular media and study the character and failure model of stone column by measuring the pressure on the bottom of stone columns.By analyzing the experiment results of single column, we could get that the column length is one of the important factors which influence the stress transferring mode. Whether the length exceeds the critical length or not is the standard that differentiates the stress transferring modes. It also shows that the failure models are different in different stress transferring modes. The experiment results of multi-column show that the columns affect each other, which can minimize the critical length effectively and advance the arch structure's formation. The arch structure in multi-column is more stable than that in single column. Also, the effect among columns will affect the bottom pressure and the influence will be different corresponding to the different stress transferring modes.Based on the theory of "granary effect" by Janssen, we build a 2-D model about the character of the stress transferring in stone column composite foundation. Our 2-D model can describe the transformation of the pressure on the bottom of single stone column when the length exceeds critical length. But it doesn't suit the case when the length is shorter than critical length. Therefore, we need to do more research on this.At the end of this thesis, we offer some advices for engineering practices to assist stone column composite foundation design and construction.