大直径矩形顶管开挖面极限支护力计算方法

为进一步研究大直径矩形顶管开挖面稳定性,通过建立实际工程地质数值模型,对大直径矩形顶管发生主动极限破坏时开挖面前方土体的破坏区域进行简化；基于破坏模式,改进现有的楔形体计算模型,推导矩形截面主动极限支护压力的计算方法；将该方法得到的极限支护力值与实际工程计算结果进行对比验证合理性,继而进行影响因素敏感性分析。结果表明：提出的梯形楔形体计算模型与数值模拟结果相近,且优于等效截面计算结果,可见本项研究能够为大直径矩形顶管在土层中顶进时的确定合理的支护压力提供依据。

Calculation method of limit support pressure for large diameter rectangular pipe jacking tunnel face

In order to further study the stability of large diameter rectangular pipe jacking tunnel face, when active limit failure of large diameter rectangular pipe jacking occurred, the failure area of soil mass in front of tunnel face was simplified by establishing a practical engineering geological numerical model. Based on the failure mode, the existing wedge calculation model was improved, and the calculation method of active limit support pressure of rectangular section was deduced. The limit support force obtained by this method was compared with calculation results obtained by the actual engineering to verify the rationality, and then the sensitivity analysis of influencing factors was carried out. The results show that the proposed calculation model of trapezoidal wedge is close to the numerical simulation results, and it is better than the results calculated by equivalent section. Therefore, this study can provide help for determining the reasonable support pressure of large diameter rectangular pipe jacking in the soil.