承受高内、外水压力的隧洞结构设计建议

Design Recommendations for Tunnel Structure Withstanding High Internal and External Water Pressure

隧洞常采用的预应力钢筋混凝土衬砌需承受高内水压力,常规有粘结或无粘结预应力钢筋混凝土衬砌需耗费大量预应力钢材、锚具和普通钢筋,而且应力分布不均匀,施工麻烦,针对这些缺点提出外加预应力衬砌法,即在围岩和衬砌混凝土之间安装一种圆环形扁千斤顶设备,根据需要人为地给隧洞衬砌施加某一数值和均匀分布的反向荷载,即外加均布荷载,用以抵消内水压力所产生的拉应力。针对高外水压力的治理,建议首先采用固结灌浆封堵,然后再将渗漏过来的水采用抽排水系统排走以有效减小外水压力。

The pre-stressed reinforced concrete lining often used in tunnels is subject to high internal water pressure.Conventional pre-stressed reinforced concrete linings usually require a large amount of pre-stressed steel, anchor and ordinary steel bars, and the stress distribution of lining are uneven and the construction is also trouble. The external pre-stressed method is proposed to solve these problems, which is achieved by installing a circular flat jack device between surrounding rocks and lining concrete. The jack device can artificially apply a uniform compressive stress on the outside of tunnel lining, which can counteract the tensile stress generated by internal water pressure. As for the high external water pressure, it is recommended that the consolidation grouting is firstly used, and then the leaked water is drained through pumping drainage system to eliminate the effect of external water pressure.