Research And Application Of Key Anti-seepage Parameters After Pipe Jacking Through Embankment

Pipe jacking technology is widely used in the development of underground space and has many advantages,but it will inevitably disturb the original soil during the construction of pipeline crossing,affecting its compactness and permeability.Especially when crossing the embankment,it may also cause a series of problems such as ground subsidence,collapse,pipe surge,etc.,and even contact leakage along the pipeline under different geological conditions,which will adversely affect the seepage safety of the embankment.Based on the background of the water intake pipeline crossing the Huaibei embankment project of Mao Ji waterworks in Huainan City,this paper analyzes the development status of grouting technology and impermeable wall technology at home and abroad,and uses ABAQUS numerical simulation software to study:(1)the influence of the pipe before and after crossing the embankment on the seepage field of the embankment;(2)the influence of the anti-seepage wall on the seepage field of the embankment after the pipeline crosses;(3)the influence of different press-tight grouting ranges on the seepage field of the embankment after the pipeline crosses;(4)The influence of the combination of anti-seepage wall and press-tight grouting on the seepage field of the embankment.By comparing and analyzing the seepage flow rate of the embankment under various working conditions,the height of the escape point on the backwater side of the embankment and the seepage flow rate of the escape boundary,the main research results obtained are as follows:(1)Numerical simulations were conducted using ABAQUS finite element software before and after the pipe was pushed through the embankment.The results showed that the elevation of the escape point on the back water side was 22.35 meters before the pipe was pushed through the embankment.In the velocity vector diagram,due to the high permeability coefficient of the sand layer,the larger velocity is mainly concentrated in the sand layer.(2)After the top pipe passes through the embankment,the seepage velocity of the embankment body changes,and there is a clear phenomenon of seepage around the pipeline,causing the flow velocity inside the embankment body to be mainly concentrated near the pipeline and at the end of the pipeline.(3)After using ABAQUS finite element software to simulate and analyze the two anti-seepage measures of anti-seepage wall and pressure grouting,it was found that the anti-seepage wall and pressure grouting have a certain effect on reducing the height of the escape point and infiltration line on the back water side of the embankment,but the antiseepage effect of the anti-seepage wall is more significant.(4)When the depth of compaction grouting exceeds a certain range,the reduction of the height of the escape point appears weak,but it has a good effect on improving the seepage phenomenon around the pipe.So if we want to better control the seepage phenomenon around the pipe and the seepage velocity at the end of the pipe,we should expand the grouting range in the horizontal direction instead of continuing to increase in the depth direction.Figure [64] table [6] reference [61]...