灰岩冻融循环的劣化规律研究

Deterioration law of limestone freeze-thaw cycles

摘要:

基于岩石损伤理论推导了冻融循环作用下岩石的损伤劣化模型，并采用冻融循环试验方式测试了后崴子隧道灰岩岩样冻融循环后的物理力学特征变化规律，分析了其损伤劣化规律。获得了岩样的质量、纵波波速随冻融循环呈现先增后减的趋势，单轴抗压强度持续减小，弹性模量和峰值应变逐渐增大的结果。分析获得了冻融循环作用下灰岩总损伤变量与应变的关系，冻融和载荷的共同作用会使总损伤加剧，但损伤曲线表明耦合作用也可适当缓解这一影响，且灰岩应变值趋于一致，表明影响灰岩强度极限的主要因素可以不考虑冻融循环。

Abstract:

Based on the rock damage theory, the damage deterioration model of rock under the freeze-thaw cycle is derived. The freeze-thaw cycle test method is used to test the physico-mechanical characteristics of the Houwaizi Tunnel limestone rock sample, and analysis is made of its damage deterioration law. The results show that the rock mass and the longitudinal wave velocity of increase first and then decreases with freezing-thawing cycle, the uniaxial compressive strength decreases continuously with freezing-thawing cycle, and the elastic modulus and peak strain increase gradually with freezing-thawing cycle. Through analysis, the relationship between the total damage variable and strain of limestone under the action of freezing-thawing cycle is obtained. The combined action of freezing-thawing and load will aggravate the total damage, the coupling effect will weaken the total damage, and the limestone strain values tend to agree that the number of freeze-thaw cycles is not the main factor affecting the strength limit.