Study On The Interaction Of Parallel Pipe Jacking

With the rapid development of economy and society,the construction of parallel pipe jacking is more and more wide.The research of this paper is mainly aimed at the interaction of parallel pipe jacking.The concrete contents are as follows:(1)The mechanism of parallel pipe jacking has been studied in detail,including the interaction between the first pipe,soil and the rear pipe during the parallel pipe jacking;the stress state change of the soil after disturbed;and the influence of different construction factors on the settlement of soil during the construction of parallel pipe jacking,etc.(2)Summarize the Peck formula of soil settlement caused by parallel pipe jacking and discuss the causes of soil settlement.(3)The finite element software Midas/GTS NX is used to simulate the parallel pipe jacking process,and analyze the stress and strain state of the soil during the construction.At the same time,the variation law of soil settlement curve under different conditions is analyzed,such as pipe spacing,pipe depth and pipe diameter,and the following conclusions are drawn:(1)During the parallel pipe jacking process,the rear pipe is disturbed by the first pipe so that the soil loss of the rear pipe is larger.And the axis of the final surface settlement curve is close to the first pipe;(2)With the increase of pipe spacing of the parallel pipe jacking,the settlement curve of soil of earth’s surface is changed from "V" to "U",and then gradually to "W".(3)With the increase of pipe depth of the parallel pipe jacking,the maximum settlement value of surface soil is getting smaller and the surface settlement curve is widened,and the shape of “narrow and deep” is turned to “Wide and shallow” continuously,but the symmetry of the formation of the displacement cloud image is not affected;(4)With the increasesof the pipe diameter of the parallel pipe jacking,the soil loss and the grouting area around the pipe is larger and larger.The axis of the soil settlement curve is closer to the larger diameter side of the pipe,and the speed of the axis movement is related to the difference in size(ratio)of the diameter.(4)Combining the soil settlement data of the parallel pipe jacking by monitoring,the Peck formula and Midas/GTS NX numerical simulation are carried out respectively and compare them.Verify the Correctness of Peck Formula and Threedimensional Numerical Simulation.