软土盾构法隧道纵向应力松弛规律的实测分析

发布时间：2018-01-26 00:30

本文关键词： 盾构法隧道纵向应力松弛松弛机理及效应现场实测　出处：《岩土工程学报》2017年05期 　论文类型：期刊论文

【摘要】：为研究软土盾构法隧道的纵向应力松弛特性,对钱江隧道典型断面的管片体、衬砌环面的纵向应力松弛特性和环间纵向连接螺栓轴力的时变特性进行了长达两年的现场实测。结果表明,软土盾构法隧道管片体的纵向应力松弛将经历周期性剧烈波动、动态稳定、逐渐衰减、趋于稳定四个阶段的演变,其纵向应力平均值由3 MPa逐渐松弛为1.2MPa,在达到稳定前至少需要1 a时间;与此同时,衬砌环缝面上的接触应力松弛也经历上述4个阶段的演变,其接触应力平均值由2 MPa逐渐松弛为1 MPa,在达到稳定前至少需要18个月;隧道环间连接螺栓轴力先减小、然后暂时稳定、最后增大,且在经历了2 a的显著波动后仍未稳定表明隧道纵向应力松弛导致接触状态仍处于复杂的演变过程之中,其最终稳定需要更长时间。软土盾构法隧道的纵向应力松弛是衬砌环间接触调整、土体隧道结构接触调整和螺栓体松弛三大要素的时变性及其共同作用的结果,可导致隧道环面接缝刚度降低、环间抗剪承载力下降、环间接缝的防水密封性能弱化等,应引起工程界重视。
[Abstract]:In order to study the longitudinal stress relaxation characteristics of soft soil shield tunnel, the segment body of typical section of Qianjiang tunnel is studied. The longitudinal stress relaxation characteristics of lining ring surface and the time-varying characteristics of axial force of longitudinal connection bolt between rings have been measured in the field for up to two years. The results show that. The longitudinal stress relaxation of soft soil shield tunnel segment body will undergo periodic violent fluctuation, dynamic stability, gradual attenuation, and tend to the evolution of the four stages of stability. The average longitudinal stress relaxes gradually from 3 MPa to 1.2 MPA, and it takes at least 1 year before reaching stability. At the same time, the contact stress relaxation on the annular surface of the lining also experienced the evolution of the above four stages, and the average contact stress gradually relaxed from 2 MPa to 1 MPa. At least 18 months before stabilization is reached; The axial force of the connecting bolt between the rings of the tunnel first decreases, then stabilizes temporarily, and finally increases. And after two years of remarkable fluctuation, it is still not stable, which indicates that the longitudinal stress relaxation of the tunnel leads to the complex evolution of the contact state. The longitudinal stress relaxation of soft soil shield tunnel is the adjustment of contact between lining rings. The time variation of contact adjustment and bolt relaxation of the tunnel structure and the results of the joint action can result in the decrease of the stiffness of the tunnel ring joint and the decrease of the shear bearing capacity between the rings. The waterproofing sealing performance of ring joint is weakened, which should be paid attention to by engineering circles.
【作者单位】：同济大学地下建筑与工程系;同济大学岩土与地下工程教育部重点实验室;中铁第四勘察设计院集团有限公司;
【基金】：国家重点基础研究发展计划(“973”计划)项目(2015CB057806) 国家自然科学基金项目(51378389) 山东省自然科学基金项目(ZR2016EEQ13,ZR2014EEQ28)
【分类号】：U455.43
【正文快照】： 3.中铁第四勘察设计院集团有限公司,湖北武汉430063)软土盾构法隧道在施工过程中受到盾构千斤顶推*通讯作者(E-mail:menyanqing@126.com)力作用向前延伸,使得隧道在全长范围及相当长时间内存在明显的纵向预压应力,这种纵向应力对衬砌环间渗漏水防治和纵向变形控制等至关重要[1

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