Analysis and prediction of thrust in using slurry pipe jacking method

Abstract

Pipe jacking is a name for a method to excavate a tunnel by pushing pipe into the ground from an especial pit. Size of tunnels in this method is different from under 900mm (microtunneling) to more than 3000mm. Method of excavation is also different from hand digging to use of any kind of tunnel boring machines such as slurry and earth pressure balance (EPB) machines. Slurry pipe jacking was firmly established as a special method for the non-disruptive construction of the underground pipelines of sewage systems. Pipe jacking, in its traditional form, has occasionally been used for short railways, roads, rivers, and other projects. In particular, for construction work near existing facilities; underground tunnels that are excavated by slurry pipe jacking are being increasingly employed in order to avoid problems such as subsidence. This method utilizes mud slurry that is formed around the pipes in order to stabilize the surrounding soil, reducing friction and increasing jacking distance. During the pipe jacking and microtunneling process, the jacking load is an important parameter, controlling the pipe wall thickness, the need for and location of intermediate jacking station, selection of jacking frame and lubrication requirements. The main component of the jacking load is due to frictional resistance. This paper discusses the method of prediction thrust during a slurry pipe jacking construction based on the upgrade of the last equations that submitted by Shimada and Matsui in 1998. In new equations effect of pipe weight was included and the conclusions compared with the real data and shown good relation. In this study ideal situation of jacking was considered. For the effect of influence of cutters through the soil, stoppages, unforeseen events as boulders in the way and misalignment an increase of 20% for calculated thrust in both methods are recommended. (A). Reprinted with permission from Elsevier. For the covering abstract see ITRD E124500.