不等高三连拱隧道衬砌变形分析及控制措施

为找出不等高三连拱隧道衬砌变形的原因和特点,提出相应的施工对策。以京石线DK278+824～DK279+389里程段明挖施工的不等高三连拱隧道为工程依托,针对跨高不相等的特殊结构形式,分析其受力情况,指出该段不等高三连拱隧道衬砌变形的原因及特点。结果发现:高跨隧道混凝土衬砌受到覆土压力及侧向土压力的扭转,衬砌有逆时针整体转动的趋势,隧道底部通过换填片石混凝土可以有效地控制隧道衬砌的竖向位移。通过数值模拟计算,证实了该控制措施的可行性。

Analysis on Deformation of Lining of Triple-arch Tunnel at Different Altitudes and Its Control Technologies

The tunnel from DK278＋824 to DK279＋389 on Beijing-Shijiazhuang railway is a triple-arch tunnel,with the tunnel tubes being at different altitudes.The loading conditions of the triple-arch tunnel are analyzed and the causes and features of the deformation of the triple-arch tunnel are studied.The results show that,due to the overburden pressure and the lateral soil pressure,the lining of the tunnel tube at higher altitude tends to turn in anticlockwise direction;the vertical displacement of the lining of the tunnel tube at higher altitude can be brought under effective control by means of backfilling rubble concrete at the tunnel floor.The numerical simulation proves that the displacement control technology is feasible.