Assessment of experimental friction parameters and contact property of pipe string for the estimation and verification of a solution for pipe stuck in the China's first rock pipe jacking

摘要

The first rock pipe jacking project of China in Chongqing Guanjingkou encountered a pipe sticking problem soon following the abrupt increase of jacking force. It was essential for the direct shear test results and stresses acting normal to the outer periphery of the pipe strings to be relevant in the understanding of jacking forces for the pipe stuck. In this paper, direct shear tests were performed on the frictional characteristic between a dolomite and concrete specimen using the same test method in the earlier companion paper. The normal stresses of the pipe string were obtained through plane strain finite element modeling of the pipe-jacking under different engineering geological conditions, contact characteristics, overburden and contact areas, the threshold values of the normal contact stresses increased dramatically have also been achieved, simultaneously. Then the jacking force needed for stuck pipe strings has been predicted based on the frictional test results and the normal stress simulation in order to determine where the temporary intermediate jacking stations (TIJSs) should be installed. Finally, the pipe stuck problem is solved successfully using the TIJS method, this result provides excellent reference data for the similar engineering problems in the future.