Calculation Method Of Geogrid-encased Stone Columns’ Bearing Capacity And Settlement Based On Cavity Expansion Theory

With the rapid development of the economy of our country,the treatment of soft soil foundation under large-scale heaping of factory buildings,docks,embankments and large oil tanks has become a more and more common problem in engineering construction.The force mechanism of the reinforced hoop crushed stone piles are subject to the concern of many scholars for the good effect of its foundation treatment.Compared with the ordinary gravel pile composite foundation,the research on the composite foundation of the crushed stone pile is still at the initial stage,neither the theoretical research nor the related experiment has formed a mature system.On the basis of existing research,this paper combines with the National Natural Science Foundation of China,"the hoop crushed stone pile composite foundation bearing mechanism and design calculation method"(project number:51208191)and "traffic under the load of rigid pile composite foundation(51478178).Through the theoretical analysis and the indoor model test,the stress deformation mechanism and the design calculation theory of the crushed stone pile composite foundation are studied and discussed.First of all,a detailed understanding of the various types of composite foundation with gravel pile composite foundation,and a brief introduction to the research status of the composite foundation of the hoop crushed stone pile,and the existing deformation deformation mechanism are described fully.Then,according to the theory of Vesic circular hole expansion,it is reasonable to assume that the effective earth pressure of the single pile is the static earth pressure,and then the Lame formula can be used to study the deformation of the hoop casing pile composite foundation,and then based on the assumption of pile-soil interface,the pile foundation settlement calculation method of the composite foundation of the hoop crushed-stone pile is analyzed and studied.At the same time,the indoor large scale model test of the composite foundation of the hoop crushed stone pile is designed,and the method is validated and analyzed from the mechanics of the deformation of the ordinary gravel pile composite foundation and the results of the existing laboratory tests.The optimum reinforcement depth of crushed stone pile is discussed.At last,the engineering examples of soft soil foundation treatment by using the composite foundation with tendons and crushed stone pile are selected,and the relevant parameters of the deformation of the crushed stone pile are discussed and analyzed.On the basis of the circular hole expansion theory,The rationality of the calculation method of bearing capacity and settlement of gravel pile is verified again.