黄土连拱隧道支护结构力学特性现场试验

发布时间：2018-08-11 17:25

【摘要】：为研究黄土连拱隧道支护体系力学特性,文章以某黄土连拱隧道为依托,采用钢弦式传感器,对围岩压力、锚杆轴力、钢支撑内力以及二次衬砌受力等进行系统测试与分析。结果表明:(1)在中墙墙顶与拱部的结合处以及在墙底与仰拱的结合处,围岩压力的波动比较大,最大压力值分别为195 kPa、115 kPa。位于围岩级别过渡段的隧道仰拱中心处的压力值较大,最大值为267 kPa,隧底出现较大底鼓趋势。围岩压力整体呈"双马鞍形"分布;(2)深埋段竖向围岩压力实测值与《公路隧规》中按连拱隧道半跨计算的结果比较接近。浅埋段按不同围岩压力计算公式得到的压力值均大于实测值,采用太沙基公式得到的压力值与实测值相对接近;(3)该黄土连拱隧道的初期支护与二次衬砌的荷载分担比例为47.66%和52.34%,二次衬砌处于明显的承载状态;(4)锚杆轴力较小,呈"鱼肚形"分布。钢拱架承受的荷载较大,在钢拱架强支护的作用下,锚杆发挥的作用有限;(5)中墙扭矩的存在,验证了黄土隧道中纵向效应的存在,在设计与施工的过程中应该加以重视。
[Abstract]:In order to study the mechanical characteristics of the supporting system of the Loess multi-arch tunnel, a steel wire type sensor is used to measure and analyze the surrounding rock pressure, the axial force of the bolt, the internal force of the steel support and the secondary lining force. The maximum pressure is 195 kPa and 115 kPa, respectively. The maximum value is 267 kPa at the center of the inverted arch of the tunnel at the transition section of the surrounding rock grade, and there is a large floor heave tendency at the bottom of the tunnel. The calculation results of the half span of the double-arch tunnel are close to each other. The pressure values of the shallow section calculated by different formulas of surrounding rock pressure are all greater than the measured values, and the pressure values obtained by the Terzaghi formula are relatively close to the measured values. (3) The load sharing ratio of the primary support and the secondary lining of the double-arch tunnel is 47.66% and 52.34%, and the secondary lining is 47.66%. The masonry is in an obvious bearing state; (4) the axial force of the bolt is small and the bolt is in the shape of "fish belly". The load of the steel arch frame is large, and the bolt plays a limited role under the strong support of the steel arch frame; (5) the existence of the middle wall torque verifies the existence of the longitudinal effect in the Loess tunnel, which should be paid attention to in the process of design and construction.
【作者单位】：长安大学公路学院;
【基金】：国家自然科学基金(51008029) 交通运输部西部交通建设科技项目(2007 318 000 18)
【分类号】：U451.5

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