喷膜防水衬砌在渗流场作用下的力学性能研究

Mechanical Properties of Spray-Applied Waterproofing Lining Under Seepage Fields Effect

喷膜防水衬砌结构在防水膜黏结作用和渗流场作用下的衬砌受力变形规律不明,影响了喷膜防水衬砌结构的使用与推广。为解决该问题,以某高速车行横洞为研究对象,首先,结合试验测得的界面法向、切向参数,采用FLAC3D有限差分软件内置的界面单元模拟不同防水衬砌结构的防水层形式;然后,通过内置的渗流模式赋予围岩渗流场与衬砌渗透属性;最后,对不同衬砌结构的力学性能和界面特性进行对比分析,模拟得到不同渗流场作用下的喷膜防水衬砌力学性能。研究结果表明:1)防水层对衬砌受力的影响显著,防水膜结构可以提高衬砌混凝土的协同受力能力,但也导致衬砌背后水压聚集;且在长期围岩荷载和高水压作用下,防水层对衬砌受力的影响更显著。2)高水压条件下喷膜防水衬砌与传统复合式衬砌的结构受力不同,应关注喷膜防水衬砌内力与安全系数变化。3)为了在保证隧道运营安全的条件下提高经济性,建议对可能出现高水压力的施工段采取排水设计和衬砌结构优化等措施。

The law of bonding and deformation of spray-applied wagterproofing lining under seepage field is unclear,which affects the application and popularization of spray-applied waterproofing lining structure.To address this problem,a high-speed cross tunnel is taken as the research object.First,the varied forms of waterproof layers for different waterproof lining structures are simulated using the built-in interface elements of FLAC3D finite difference software based on tested interface normal and circumferential parameters.Then,the surrounding rock seepage field and lining permeability performance are given attributes through the built-in seepage modes,and the mechanical properties and interface characteristics of different lining structures are compared and analyzed.Finally,the mechanical properties of spray-applied waterproofing lining are obtained under different seepage fields.The results indicate the following.(1)The waterproof layer has a considerable impact on lining stress.Adopting an appropriate waterproof membrane structure can improve the collaborative stress capacity of the lining concrete;however,it causes an accumulation of water pressure behind the lining.This effect is more significant under long-term rock loading and high water pressure.(2)Under high water-pressure conditions,the structural stresses of the spray-applied waterproofing lining differ from those of the traditional composite lining;in particular,the changes in internal force and safety factors should be examined.(3)The economy of the lining should be improved under the condition of the safety of tunnel operation.For the construction sections in which high water pressure is likely,adopting measures such as drainage design and lining structure optimization is recommended.