注浆整治盾构隧道横向大变形下地层响应现场试验研究

    Field test insights on mechanical behaviors of ground around a large deformed shield tunnel rehabilitated by grouting

    • 摘要: 微扰动注浆技术在整治盾构隧道的横向大变形方面已得到广泛应用,但针对注浆过程中周边地层力学响应的研究仍相对缺乏。依托上海地区某微扰动注浆整治盾构隧道横向变形的案例,在现场选取了一环管片衬砌作为测试环,于该测试环对应的注浆孔两侧布设了压力传感器,监测其土压力及孔隙水压力的变化。据此分析了注浆过程中该注浆孔附近地层的附加土压力、超孔隙水压力及有效应力的变化规律,并进一步分析了后续3个邻近注浆孔在注浆过程中引起该测试位置地层的力学响应规律。在此基础上,结合注浆期间的附加土压力变化,修正了现有注浆效率计算式中的浆液分配系数,为定量表征注浆体于二维平面上的不确定性以及注浆参数工程实践设计提供了新思路。

       

      Abstract: At present, light-disturbance grouting technology has been widely applied in controlling and rehabilitating the transverse deformation of existing shield tunnels. However, there is a lack of corresponding research on the stratigraphic mechanical response during the minor-disturbance grouting process. This paper relies on a case study of transverse deformation rehabilitation of shield tunnels treated with minor-disturbance grouting in Shanghai. A lining ring is selected as a test ring at the site, with pressure sensors installed on both sides of the grouting hole to monitor the variations in earth pressure and pore water pressure. Based on this, the variations of the additional earth pressure, excess pore water pressure, and effective stress near the grouting hole during the grouting process are analyzed. Furthermore, the mechanical response of the ground at the test location induced by the grouting process of three adjacent grouting holes is further analyzed. On this basis, the slurry distribution coefficients in the existing grouting efficiency equations are corrected in conjunction with the additional earth pressure variations during grouting, and this provided a new idea for quantitatively characterizing the uncertainty of the grouting body in a two-dimensional plane and the design of grouting parameters in engineering practice.

       

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