【摘要】 盾构施工过程中地质条件变化、刀盘旋转切割土体、停盾拼装管片等因素会造成开挖面推力的波动,从而在开挖面前方产生超孔压,此超孔压对开挖面稳定性的影响需进行分析。首先通过建立分层土分析模型,结合太沙基固结理论,得到开挖面前方超孔压的计算方法;进而采用楔形体模型,给出超孔压对开挖面稳定性影响的计算方法。计算结果显示超孔压将显著降低开挖面的安全系数,因此在开挖面最小支护力的计算中需考虑推力波动变化的影响。最后通过参数分析给出了不同工况下产生的超孔压及其对开挖面安全系数影响的大小,为盾构施工参数的制定提供了参考。更多还原

【Abstract】 In shield tunnlling there are many factors can affect the stability of the thrust force such as the changes of geology conditions,soil cutting by the cutter head,and the regular stop of the shield for segment assembly. The excess pore water pressure caused by the fluctuations force can be accumulated so large that the stability of the tunnel face could be affected. The layered soil analysis model was established at first and the calculation method of the excess pore water pressure near tunnel face was obtained by combining the Terzaghi?s one-dimensional consolidation theory. Then the calculation method of the effect of the excess pore water pressure on the tunnel face stability was given out using the wedge analysis model. From the calculation result it can be concluded that the safety factor of tunnel face can be reduced by the excess pore water pressure. So the effect of the fluctuations thrust force should be considered in the calculation of the minimum support face pressure. At last the excess pore water pressure and the decreasing coefficient of safety factor with different construction conditions were given out through parameter analysis.更多还原