Within The Pile Soil Nailing Support Joint Supporting Structure By Numerical Simulation

Composite retaining of cement-soil pile and soiling nailing (CRCSPSN), as a new mode of composite nailing structure, has the technical effects of transmitting strength through friction, waterproofing, nailing and retaining soil. It also performs well in saving resources, and reducing field displacement, improving the quality of self-reliance of the construction site, protecting the surrounding environment and shortening project execution time. These effects have been widely verified in practice.Researchers have executed a series of researches on the computational model and working mechanism of CRCSPSN and made great achievements. The increment method is an effective way developed to measure the force of soil-nail and pit deformation.This thesis reviewed the previous studies of CRCSPSN and analyzed the stability, working mechanism, mechanics of strength transmission and state of deformation of CRCSPSN by combining the research methods of theoretical investigation, case study and numerical simulation. The main content of this thesis is as following:(1) Summarizing the developmental history of soiling nailing structure, with special emphasis attached to its stability, and introducing different failure forms of soil nailing wall and composite soil nailing wall and their corresponding force bearing mechanism.(2) Analyzing the working mechanism of the cement-soil pile of cement soil mixing CRCSPSN which includes transmitting strength through friction, waterproofing, antedisplacementing dominant sliding surface and making the construction site more self-reliant.(3) Introducing and summarizing the increment method of measuring the force of soil-nail and pit deformation and testing it through project cases.(4) Using FLAC3D to establish a three-dimensional numerical model of the CRCSPSN pit and provide a dynamic simulation of the construction process and finally obtaining the changing patterns of the forceof soil-nail as the project process through increment method. Moreover, the variation laws of vertical displacement and horizontal displacement of the pit are gathered and showed to be consistent with previous researches.