硬石膏岩膨胀特性试验及隧道抗膨胀衬砌设计

石膏质岩的膨胀机理复杂,膨胀时间漫长,其膨胀力对隧道支护结构破坏性极强。本文采用室内试验方法研究了硬石膏岩的膨胀力学特性,得出膨胀应力-应变曲线为凹形函数,膨胀应变-时间曲线为“S”型函数, 膨胀应力-时间曲线为指数型函数等规律。基于试验结果提出了可考虑时间效应的硬石膏岩膨胀变形计算公式,进而建立硬石膏岩隧道围岩膨胀变形、膨胀应力及时间的关系,用以描述隧道修建过程中膨胀应力应变的动态变化。并提出一种新型石膏质岩隧道抗膨胀衬砌设计,从主动和被动两个方面减缓石膏岩遇水致膨胀对衬砌结构的影响,为类似工程提供借鉴与思考。

Experiment on Swelling Characteristics of Hard Gypsum Rock and Design of Anti-expansion Lining for Tunnel

The expansion time of gypsum rock is long and the expansion mechanism is complicated. The expansion force of the gypsum rock is extremely destructive to the tunnel support structure. The swelling mechanics characteristics of anhydrite gypsum studied by indoor experiment. It is concluded that expansion stress-strain shows as concave function, expansion strain-time curve shows as “S” shape functionstress-time curve shows as the exponential function. Based on the experimental results, the calculation formula of the hardened gypsum rock expansion deformation considering the time effect is put forward, and the relationship the swelling deformation, the expansion stress and the time of the surrounding rock of the anhydrite channel is established. The calculation formula can be used to describe the dynamic changes of the expanding stress and strain in the process of tunnel construction. A newanti-expansion lining design,from active and passive aspects, is put forward to reduce the impact of gypsum water on the expansion of the lining structure.This paper provides reference and reflection for similar projects.