碳化泥质板岩大断面隧道围岩松动圈测试研究

发布时间：2018-06-23 15:31

本文选题：大断面隧道 + 松动圈　；参考：《地下空间与工程学报》2017年04期

【摘要】：围岩松动圈范围是隧道、巷道及类似地下工程设计、施工和评价围岩稳定性的重要技术参数之一。针对吉图珲高速铁路小盘岭大断面碳化泥质板岩隧道在掘进过程中发生的地层变形大、频繁更换钢拱架以及隧道局部多次发生垮塌这一严重现象,采取多点位移计监测及超声波检测技术,对小盘岭隧道围岩松动圈范围进行测试。在此基础上,通过改变围岩壁后注浆深度,对比分析控制效果。现场测试表明,小盘岭隧道围岩松动范围大,平均达到约5 m,隧道开挖右侧松动圈范围大于左侧松动圈范围,原支护方案中锚杆长度仅为4.0 m,径向注浆管长度为3 m,初步判断施工步距大以及锚杆长度过短是造成隧道围岩失稳的重要因素。在后续的施工过程中,采取右侧及拱顶锚杆长度为6.5 m,左侧锚杆长度为6 m,围岩径向注浆管长度增加到5 m,经过优化后的锚杆长度参数明显改善了围岩的支护效果,监测表明隧道拱顶沉降及围岩收敛速率明显减小,拱架受力明显降低,降低了隧道施工风险,并为类似工程的设计及施工提供参考。
[Abstract]:The range of surrounding rock loose zone is one of the important technical parameters for the design, construction and evaluation of the stability of surrounding rock in tunnel, tunnel and similar underground engineering. In view of the serious phenomena of large deformation of stratum during excavation, frequent replacement of steel arch frame and local collapse of the tunnel in Xiaopanling large section of Jituhui high speed railway, the carbonized muddy slate tunnel occurred in the course of excavation. The range of surrounding rock loose circle of Xiaopanling tunnel was measured by multi-point displacement monitoring and ultrasonic detection technology. On this basis, the control effect is analyzed by changing the grouting depth behind the surrounding rock wall. The field test shows that the surrounding rock loosening range of Xiaopanling tunnel is large, which is about 5 m on average, and the range of the right side loose circle is larger than the left one. The length of anchor rod is only 4.0 m and the length of radial grouting pipe is 3 m in the original support scheme. It is preliminarily judged that the large construction step distance and too short length of anchor rod are the important factors that cause the instability of surrounding rock of tunnel. In the following construction process, the length of anchor rod on right side and arch roof is 6.5 m, the length of anchor rod on left side is 6 m, and the length of radial grouting pipe of surrounding rock is increased to 5 m. The optimized length parameter of anchor rod can obviously improve the supporting effect of surrounding rock. The monitoring results show that the settlement of tunnel arch roof and the convergence rate of surrounding rock are obviously reduced, and the stress of arch frame is obviously reduced, which reduces the risk of tunnel construction and provides a reference for the design and construction of similar projects.
【作者单位】：北京交通大学隧道及地下工程教育部工程研究中心;中铁十九局集团第五工程有限公司;中国科学院武汉岩土力学研究所;
【基金】：国家“973”项目资助(2010CB732102) 北京交通大学基本科研业务费(2011JBM078)
【分类号】：U452.12

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