Analysis On Soil Properties And Environment Effects Induced By Pipe Jacking

Pipe jacking construction disturbs soil inevitably,which would results in soil deformation and does harm to its surroundings. This thesis based on the pipe jacking construction project along Shiqiao Road in Hangzhou. By in-situ test,three dimention FEM numerical solution and theoretical analysis,a systematic research is made on the disturbance of soil,ground movements and the influence on underground pipelines induced by pipe jacking. Some useful conclusions are obtained in the thesis. The main content of the thesis is as follows:1. The disturbance of soil induced by pipe jacking is studied with theoretical method. Based on the former research,the disturbed soil is divided into different zones according to their degrees of disturbance,which is more accorded with fact. The disturbance mechanism and characteristics of soil and its influence extent induced by pipe jacking are studied. The variation of stresses and properties in the disturbed soil during jacking process is also analyzed. The disturbance of soil induced by injection is analyzed,include the injection mechanism,the seepage behavior of mud slurry on soil around pipe and the influence factors of injection effect.2. The in-situ monitoring is made on the disturbance of soil induced by pipe jacking construction. The in-situ testing includes surface deformations,sub-surface movements,earth pressures,pore water pressures,underground water levels,SPT,stresses of pipes and pipe-soil contact stresses. In addition,the total jacking forces,deviations in line and level of the pipe line and earth pressures in the earth pressure balance machines (EPBM) are also recorded. The results of field-testing are analyzed,and the variety of testing datum include earth pressures,pore water pressures and underground water levels during the course of the shield through it are studied.3. The reasons inducing the surface deformation and deformation mechanism during pipe jacking are studied. By analysis the results of in-situ monitoring in the process of pipe jacking,the law of surface deformation perpendicular to pipe axis and along pipe axis,the sub-surface movements perpendicular to the axis of pipe and along the axis of pipe are studied. In addition,the influence factors of sub-surface movements are also analyzed.4. The influence on its surroundings including neighborhood buildings,constructions,underground pipelines and roads induced by pipe jacking construction are investigated. The deformation of parallel buried pipelines and perpendicularly crossing buried pipelines induced by pipe jacking is analyzed by 3-D FEM. The displacement pattern of buried pipelines and its influence factors are studied. Themeasures for protecting neighborhood underground pipelines and relevantly controlling measures for minishing the ground movements during pipe jacking are advanced.