Research and Application on Freeing from Pipe Stuck Technology of Large-diameter and Long-distance Pipe Jacking Construction in Complex Geology

Abstract

Pipe jacking technology is mainly applied to road-crossing place where excavation is not applicable. So far, there is no mature experience in domestic being appropriate for long-distance and large-diameter pipe jacking passing through mountainous area with complicated geology, where obstruction problem like pipe stuck often happens [1] . This thesis does analyses on the reason for long-distance and large-diameter pipe jacking in mountainous area getting stuck and does discussion on freeing from pipe stuck. Combining with engineering examples, these methods have been put into practical application, which achieves good effects and socioeconomic benefits. It also provides guidance and reference for similar projects. Introduction Pipe jacking construction is a kind of non-excavation construction methods, which achieves pipeline, lay with on excavation or less excavation. With the aid of jacking force from jacking device in working well, pipe jacking construction overcomes friction of pipeline and surrounding soil, jacking pipelines into soil according to the designed gradient and direction and carries away the earth [2] . After the first section of pipe is jacked into soil, the second would be continued jacking. These pipe sections are produced in prefabricated field, which would be transported to engineering field, hanged into working well and jacked into the rock. Simultaneously do pipe jacking and micro shield operations on tunnel face on the front end of pipe section. With propelling forward, muck would be taken outside the tunnel by slurry. For the sake of reducing pipe jacking resistance, inject thixotropic anti-friction slurry on the back of tunnel pipe section so as to form slurry jacket of certain thickness thus leading pipe jacking to continue in the slurry jacket and reducing resistance. At the present stage, pipe jacking technology has become the main measure for no-dig construction of urban underground pipeline, which has been widely utilized in fields like drainage, sewage treatment, power pipeline, places being inconvenient for excavation, etc. Along with constantly accelerating of urbanization in our country, people keep high requirements on beautiful life, ecological protection and green construction. Keeping features of low noise, low pollution and low impact, pipe jacking construction is leaded to develop toward complex direction with large diameter, long distance, thick covering soil and complex curve [3] . While long jacking distance leads pipes to cross different stratums. When pipes encounter the weak stratum, jacking becomes difficult and even pipe stuck happens. On the basis of it, this thesis analyzes the reason for pipe stuck in pipe jacking operation, discusses methods for freeing from pipe stuck and does practical application. This provides certain practical experience for technology of extricating pipe from stuck in pipe jacking construction with large diameter, long distance and complex geology.