Abstract:

During the construction of underground works by pipe jacking method, surface deformation is often caused by construction disturbances, and there is a great safety risk during the construction process. Therefore, it is of great significance to study the law of surface deformation in the process of pipe jacking, and explore the surface deformation control technology for ensuring the safety of the pipe jacking. The surface deformation influencing factors, i.e. thickness of covering soil, soil loss during construction and effect of smallspacing tunnel construction on adjacent tunnel, are analyzed by taking a rectangular pipe jacking project constructed by structural cut and convert （CC） method for the first time in China for example. The analytical results show that: (1) The surface deformation has been brought under effective control by controlling excavation speed, soil chamber stress, grouting amount, mucking amount and pipe attitude. (2) The surface deformation varies with thrusting, and it becomes stable by adjusting soil chamber stress and supplementary grouting. (3) The effectiveness and necessity of the deformation control measures are verified by deformation monitoring data analysis.

Key words: rectangular pipe jacking, shallow cover, small spacing, boring speed, soil chamber press, boring attitude