复杂卸荷条件下卤水流量对盐岩溶解损伤特征研究  

Effect of brine flux on damage and dissolving characteristics of rock salt under the condition of complex stress unloading

作　　者：张军伟[1,2] 姜德义 陈结[1,3] 赵云峰[1] 程艳飞[1] ZHANG Jun-wei JIANG De-yi CHEN Jie ZHAO Yun-feng CHENG Yan-fei(State Key Laboratory for the Coal Mine Disaster Dynamics and Controls, Chongqing University, Chongqing 400044, China Chongqing Construction Engineering Municipal Traffic Engineering Co., Ltd., 430021 Institute of Rock and Soil Mechanics, Chinese Academy of Sciences, Wuhan, Hubei 430071, China)

机构地区：[1]重庆大学煤矿灾害动力学与控制国家重点实验室,重庆400044 [2]重庆建工市政交通工程有限责任公司,重庆400021 [3]中国科学院武汉岩土力学研究所,湖北武汉430071

出　　处：《岩土力学》2017年第3期640-648,655,共10页Rock and Soil Mechanics

基　　金：中央高校基金(No.106112016CDJZR245518);国家自然科学基金(No.51574048;No.41672292;No.51604044)~~

摘　　要：为了解水溶造腔过程中盐腔围岩在应力-溶解耦合作用下的溶解损伤机制,利用高温三轴盐岩溶解特性试验机,开展了复杂卸荷条件下(即卸围压的同时增加轴压)不同卤水流量对盐岩的溶解损伤特征研究。研究发现,盐岩的应力和溶解作用相互影响,共同决定盐岩试件在卸荷溶解过程中的变化特征。表现为:卸荷过程中偏应力越大,盐岩溶出速率越大,而且出水口卤水浓度随卸荷溶解时间呈现显著的二次函数关系;盐岩在溶解作用下其力学强度降低,变形能力不断增强,而且流量越大,变化趋势越明显。通过对盐岩卸荷溶解过程中有效溶解面积构成的分析,建立了盐岩卸荷溶解作用下的有效溶解面积模型,分别得到了各有效溶解面积随溶解时间和应力水平的变化方程,并在此基础上构建了盐岩卸荷溶解损伤演化方程,为进一步开展盐岩的损伤-溶解机制研究提供了理论和试验基础。To understand the dissolution damage mechanism of the salt cavity surrounding rock in the process of water-soluble cavitation, the high-temperature triaxial dissolution testing machine is applied to conduct tests on salt rock specimens under complex unloading conditions（i.e. unloading confining pressure, increasing axial compression） with different brine flux. It is found that the stress and dissolution influence on each other, and the damage and dissolving characteristics of salt specimens are mutually decide in the process of unloading tests. It is shown that the higher the deviatoric stress is, the greater the amount of dissolved salt rock per unit time is. The outlet concentration of brine exhibits a significant quadratic function relation with the dissolving time. The mechanical strength of salt rock is constantly reduced and its capability of deformation is enhanced under the effect of dissolving. The greater the flux is, the more obvious change trend is. Then, a model of effective dissolving area under the coupled action of stress unloading and water dissolving is set up based on the analysis of effective dissolved area in unloading and dissolution of salt rock. The variation equations of the effective dissolution area with the dissolving time and stress level are obtained respectively. An unloading and dissolving damage evolution equation is established based on the effective dissolving area. The results can provide an important theoretical and experimental basis for further analysis of damage and dissolving mechanism of salt rock.

关 键 词：盐岩溶解 卸荷 卤水流量 有效溶解面积 损伤演化 

分 类 号：U456.31[建筑科学—桥梁与隧道工程]