在役岩溶公路隧道模型试验研究

Study on Model Test of In-service Karst Highway Tunnel

以某高速公路某隧道为依托,在优选岩溶填充物、围岩和衬砌材料的相似材料的基础上,开展了几何相似比为1∶40的在役岩溶公路隧道室内相似模型试验,详细分析了对围岩土压力的分布规律和发展趋势,揭示了隧道岩溶处治后的隧道围岩和衬砌力学行为。试验结果表明:1重晶石粉、石膏粉、水泥按1∶12∶2的配比为胶结料,砂胶比3∶1,砂胶混合料水灰比1∶8,能较好的模拟Ⅴ级围岩;2在上覆岩层自重荷载作用下,以低于隧道围岩弹性模量的材料填充岩溶后,会导致填充材料产生比围岩更大的压缩变形,从而引起围岩土压力重分布和地表不均匀沉降;3当岩溶处在衬砌拱肩、拱腰和拱脚时,经处治后的岩溶仍对衬砌产生偏压的不利作用,需要引起高度重视。

This article,based on the Baishan Tunnel,optimized the selection from the simulation materials of karsts filler,surrounding rock and lining,took a study on indoor similar model test of in-service karst highway tunnel with the geometric similarity ratio of 1 /40. Then,the distribution law and development trend of surrounding rock pressure were revealed. After that,the mechanical behaviors of the surrounding rock and lining were studied after endowing some treatment to these caves in detail. The results show that： ①the Ⅴ surrounding rock can be properly simulated by the mixture of barite powder,plaster powder and cement with the proportion of 1 ∶ 12 ∶ 2; ②using smaller elastic modulus material（ compared to that of surrounding rock） to fill those caves,will lead to greater compression deformation with the dead load of upper rocks; ③when these caves were laid nearby spandrel,haunch and springing of the tunnel lining,karst caves will be harmful to cause unsymmetrical pressure to tunnel lining,although that caves have been filled by the test filler and should be attached great importance.