Analysis Of Soil Disturbance Caused By Pipe Jacking With Large Diameter And Shallow Overburden

Pipe jacking,also known as ground shield machine,is an important method in the field of underground space development in our country.But the pipe jacking construction will inevitably cause the disturbance of the surrounding soil,especially to the environment of the subsurface soil layer.Therefore,it is urgent to study the soil disturbance caused by pipe jacking under the condition of shallow overburden.In this paper,the analytical solution of initial stress isotropy for soil disturbance theory is derived.Secondly,based on the analysis of initial stress isotropy,the perturbation theory of initial stress isotropy soil is analyzed.Considering the influence of cohesive force,seepage field and other factors,the analytical solutions of plastic disturbed zone radius and stress-strain field of soil are established,and the relationship between the radius of disturbed zone and the reaming pressure is analyzed,the general law of soil disturbance under initial stress isotropy and anisotropy is obtained.At the same time,the lateral horizontal distance of soil disturbance is obtained based on the radius of plastic disturbance zone.The main conclusions of the study are as follows:1.In the theoretical analysis of initial stress isotropic soil disturbance,the influence of cohesive force and seepage force on the stress field and the radius of soil plastic disturbance zone are considered respectively.It is found that the larger the cohesion,the smaller the radius of plastic disturbed zone,the lower the degree of soil disturbance,and the reaming pressure decreases with the increase of seepage force,the influence of seepage force can not be ignored.2.In the theoretical analysis of initial stress anisotropy soil disturbance,the soil structure disturbance degree is evaluated by sensitivity.The results show that the radius of plastic zone increases with the increase of sensitivity,so the influence of structural disturbance on the disturbed range of soil can not be ignored.3.By comparing the results of initial stress isotropy theory analysis and initial stress anisotropy theory analysis,it is found that the perturbation radius solution of initial stress anisotropy soil is more in line with the practice of pipe jacking construction with shallow cover soil.4.According to the field test data,the specific values of the horizontal disturbance range are obtained,which verifies the feasibility of the theoretical calculation.The results show that the soil pressure and pore water pressure will be affected by pipe jacking,and the soil disturbance near pipe jacking will change obviously.Figure [38] Table [39] Reference [58]...