盾构隧道始发与到达段环间纵向压力空间分布规律研究

现场实测数据表明,盾构隧道始发与到达段各断面纵向压力较小,可能导致环缝漏水。为解决此问题,通过求解描述隧道变形特征的微分方程,获得隧道始发与到达段纵向力的分布规律;并以此为依据,提出纵向拉结构件的设计方法。研究结果表明： 1)在不采用拉结措施的情况下,进出洞口附近纵向力最小,接近于0; 2)距离洞口越远的断面,其纵向力越大; 3)采用纵向拉结措施可以有效地增大始发与到达段断面纵向力。在对纵向拉结构件进行设计时,其最小横截面积由隧道刚度和环缝止水垫闭合压力决定,其最小长度由隧道和地层之间的切向黏结刚度决定。

Study on Spatial Distribution Law of LongitudinalPressure betweenLaunching and Reaching Sections ofShield Tunnel

The field monitoring data demonstrate thatlongitudinal pressure of each cross section between launching andreaching sections of shield tunnel is very small, which would lead to waterleakage. As a result, the distribution of longitudinal stress is proposed bysolving differential equations describing tunnel deformation characteristics,and based on which, the design method of the longitudinal tie component isproposed. The results show that: (1) The longitudinal stress near the tunnelportal is the smallest(close to zero) without longitudinal tie. (2) Thelongitudinal stress increases with the distance from tunnel portal increase.(3) The longitudinal stress can be effectively increased between the launchingand reaching sections by adopting longitudinal tie. The minimum cross sectional area of longitudinal tie component is determined by thetunnel stiffness and the closure pressure of the annular joint waterstopgasket, and the minimum length is determined by the tangential bondingstiffness between the tunnel and stratum.