有水压隧道工程丙烯酸盐喷膜防排水结构的水平卸压性能探讨

摘要

The effect of spray-applied acrylate waterproof membrane structure on the water-pressure level relieving performance of geotextile is analyzed and discussed based on porous medium model and level water-pressure relieving tests in the light of the features of spray-applied acrylate waterproof membrane structure and the environmental conditions of rich-water tunnel engineering. A conversion method for exerting lateral pressure in level drainage experiments, the bolt torque, is applied the first time in experiments, and the relationship between macroscopic variable ( hw ) and microcosmic variable ( q) is established in later analyses to, which demonstrate the hypothesis of porous medium model and providing guidance for quantitative selection of geotextile specifications. The analyses of porous medium model shows that the equivalent water-pressure relieving thickness hw is an important parameter which effects equivalent flow area directly and changes water pressure-relieving performance of the waterproof structure. The level water-pressure relieving experiments show that the effect of spray-applied acrylate waterproof membrane on the geotextile of low specification is greater than that on the geotextile of high specification. The effecting rate of hw reaches -30% ~-70% for geotextile of low specification ( 90 g/m2 and 110 g/m2 ) and the effecting rate of hw is less than-20% for geotextile of the specification of up to 230 g/m2 and 380 g/m2 .%根据丙烯酸盐喷膜防排水结构特点、富水区隧道工程的环境条件,基于多孔介质模型和水平卸压试验,分析和探讨丙烯酸盐喷膜防水层的施作对土工布排水层水平方向上卸压性能的影响。试验首次将螺栓扭矩———预紧力换算法用于防排水试验法向接触压力的施加,同时,在后期数据分析中建立防排水结构卸压过程中微观变量(等效卸压厚度hw )与宏观变量(单位压强卸压流量q)之间的线性关系,论证多孔介质模型假说,为喷膜后土工布规格的定量选取提供一定的设计指导。模型分析表明,等效卸压厚度hw 为重要参数,其直接影响结构等效过水面积,从而改变结构卸压能力；水平卸压试验结果表明,丙烯酸盐喷膜防水层的施加对低规格土工布(90,110 g/m2)的卸压能力影响较大,hw 值影响率达到了-30%~-70%,而当土工布规格达到230 g/m2和380 g/m2时,影响已经较小,hw 值影响率均在-20%以下。