Abstract:

A stable soil arch between adjacent pipe jacks should be formed to prevent local collapse of the soil around the piperoof. Hence, the spacing of the pipe jacking should be rationally controlled. The soil arch between pipes formed at the top, middle and bottom of the fullface supported pipe curtain project is analyzed by soil arch theory based on supporting mechanism of piperoof;and the corresponding models of soil arch between pipes are established to analyze the force distribution of soil arch. The pipe jacking spacing control equation is obtained by using limit equilibrium condition of soil mass to check the stability of arch top and arch feet. The soil parameters of piperoof of Gongbei Tunnel of Hong KongZhuhaiMacao Bridge are analyzed to calculate the pipe jacking spacing, and the calculation result is 0.47 m, which is larger than actual value and indicates the rationality of the model mentioned above.

Key words: Gongbei Tunnel, piperoof method, soil arching effect, pipe jacking spacing, grouting reinforcement