黏土岩饱和过程中水分运移规律试验研究  

Experiment on moisture migration in saturation process of clayey rock

作　　者：陈卫忠[1,2] 雷江[1,3] 于洪丹 李翻翻[1,3] 马永尚 闫宪洋[4] CHEN Wei-zhong;LEI Jiang;YU Hong-dan;LI Fan-fan;MA Yong-shang;YAN Xian-yang(State Key Laboratory of Geomechanics and Geotechnical Engineering,Institute of Rock and Soil Mechanics,Chinese Academy of Sciences,Wuhan,Hubei 430071,China;Geotechnical and Structural Engineering Research Center,Shandong University,Jinan,Shandong 250061,China;University of Chinese Academy,CAS,Beijing,100049,China;Dongtan Coal Mine,Yanzhou Coal Mining Company Limited,Zoucheng,Shandong 273500,China)

机构地区：[1]中国科学院武汉岩土力学研究所岩土力学与工程国家重点实验室,湖北武汉430071 [2]山东大学岩土与结构工程研究中心,山东济南250061 [3]中国科学院大学,北京100049 [4]兖州煤业股份有限公司东滩煤矿,山东邹城273500

出　　处：《岩土力学》2019年第9期3327-3334,3343,共9页Rock and Soil Mechanics

基　　金：国家自然科学基金资助项目（No.51879258）;国家自然科学基金创新群体（No.51621006）;中国科学院青年创新促进会项目~~

摘　　要：黏土岩作为高放废物地质处置库的备选介质,目前得到世界各国的高度重视。黏土岩地质处置库巷道施工过程中,一方面,围岩因开挖损伤生成裂隙使得渗透性增强,对核素的阻滞作用降低;另一方面,在应力和水的耦合作用下,黏土岩良好的裂隙渗透损伤自修复能力使得围岩的渗透性逐渐恢复接近于原始状态。基于电阻率测试,首先开展了黏土岩试样在不同条件下的饱和过程试验研究,得到了黏土岩试样饱和过程中等效电阻率的变化规律,分析了不同损伤程度试样、盐溶液对等效电阻率的影响,进而揭示黏土岩饱和过程中水分运移规律。试验结果表明:(1)等效电阻率随着含水率增加而逐渐减小,并逐渐趋于一个稳定值;(2)等效电阻率的大小不仅与含水率有关,试样内部裂隙的存在也会影响等效电阻率分布,这一发现为电阻率法可以探测试样中裂隙的存在提供了依据;(3)水流在黏土岩中扩散,内部裂隙成为优先通道,水流在裂隙中的快速扩散加快了黏土岩的饱和速度。同时,随着黏土岩中水分与黏土矿物的水化膨胀反应,内部裂隙有一定程度闭合,加深对裂隙闭合机制认识,通过电阻率测试可以有效地揭示这一过程。Clayey rock, an alternative medium for the geological disposal of high-level waste, is highly valued by many countries. For the clayey rock underground disposal repository, the excavation of the gallery damages the host rock and further induces the propagation of the internal fractures. During this construction process, on the one hand, the permeability of the host rock increases, which reduces its capacity for retaining radionuclides. On the other hand, due to the hydro-mechanical coupling effect, the internal fractures are gradually sealed as the clayey rock has good self-sealing properties. Then the fracture permeability may recover slowly until close to the original rock state after an extremely long time span. In this paper, the experimental studies are carried out to investigate the saturation process of clayey rock under different conditions by means of the resistivity measurements. The effects of damage degree and the saline solution on the saturation process of clayey rock are studied by measuring the equivalent resistivity. The results show that:(1) The equivalent resistivity decreases gradually with the increase of the saturation and finally tends to a steady value.(2) The equivalent resistivity is not only closely related to the saturation but also the internal structure of the clayey rock. The relation between the fissures and the resistivity distribution provides guidance to detect the fissures in the clayey rock by using the resistivity method.(3) The fracture becomes the preferential channel for the water flow in the clay rock. Due to the hydration expansion reaction between water and clay minerals, the fracture seals to a certain extent, which can be indirectly reflected by the resistivity test.

关 键 词：黏土岩 水分运移 裂隙闭合 电阻率法 

分 类 号：TU411[建筑科学—岩土工程]