巴彦诺日公地段花岗岩微裂隙发育特征研究  

DEVELOPMENT OF THE GRANITE MICROCRACKS IN BAYANNUOERGONG,ALXA,INNER MONGOLIA

作　　者：董艳辉[1] 宋凡 周鹏鹏[1] 王礼恒[1] 魏亚强[1] 童少青 段瑞琪 DONG Yanhui;SONG Fan;ZHOU Pengpeng;WANG Liheng;WEI Yaqiang;TONG Shaoqing;DUAN Ruiqi(Institute of Geology and Geophysics,Chinese Academy of Sciences,Beijing100029;Information Center（Hydrology and Water Resources Monitoring and Forecasting Center）,The Ministry of Water Resources of thePeople s Republic of China,Beijing100053;Hydrology and Water Resources Monitoring and Evaluation Center（National Groundwater Monitoring Center）,The Ministry ofWater Resources of the People s Republic of China,Beijing100053）（4.University of Chinese Academy of Sciences,Beijing100049)

机构地区：[1]中国科学院地质与地球物理研究所,北京100029 [2]水利部信息中心(水利部水文水资源监测预报中心),北京100053 [3]水利部水文水资源监测评价中心(水利部国家地下水监测中心),北京100053 [4]中国科学院大学,北京100049

出　　处：《工程地质学报》2018年第3期572-582,共11页Journal of Engineering Geology

基　　金：国防科工局高放废物地质处置研究开发项目"内蒙阿拉善高放废物地质处置备选场址预选及评价研究"资助

摘　　要：花岗岩是高放射核废料地质处置库的主要围岩之一,其水力学特征优劣直接决定了花岗岩体能否有效地阻隔地下水对处置库中核废物的侵袭。围岩微裂隙结构和化学风化程度是水力学特征的直观表现,微裂隙结构量化和化学风化程度计算对高放射核废料地质处置库埋藏深度的比选有一定的科学意义。本文以阿拉善某600 m的花岗岩钻孔内不同深度的岩芯作为研究对象,得到大量的微裂隙显微照片;通过测网法和图像处理技术,获得岩芯数字化的裂隙空间分布图像,并从中提取了微裂隙特征参数(裂隙条数、隙宽、裂隙率、裂隙面密度参数等);然后,对微裂隙特征参数进行了统计分析,描述了裂隙空间分布变异性。花岗岩样品的化学风化程度评价指标有:天然含水率、CIA。同时,利用SEM-EDS探测裂隙部位形貌特征及元素含量等数据。最后,对花岗岩完整性与核废料处置库适宜性进行综合评价。通过本研究,得到了以下结论:(1)研究区的花岗岩微裂隙发育情况随深度增大逐渐变弱。(2)花岗岩受外力作用后微裂隙首先发育在石英中,其次是在长石和黑云母中。(3)临近破碎带,裂隙率、平均隙宽、裂隙条数均增大,同时受后期热液填充的影响,CIA也会表现出高值。(4)破碎带的发育,对周边完整岩体的微观破裂影响距离可以超过10.6 m,后期热液对下方完整岩体的侵染蚀变影响距离可以超过50.27 m。(5)通过综合评价,来自该钻孔不同深度的7个样品中,取自地下598.8 m处的样品所代表的位置最适宜作为核废料处置库深埋区。Granite is a kind of surrounding rock in high-level radioactive waste geological repository. Hydraulic characteristics of the surrounding rock directly determine whether or not it can effectively block the groundwater tothe direction of nuclear waste repository. The micro cracks structure and chemical weathering is the performance of hydraulic characteristics in surrounding rock. So a quantitative analysis of granite micro cracks and chemical weathering analysis has the certain scientific significance for comparison of the buried depth of high-level radioactive waste geological repository. In this study,seven core samples in different depth of the granite drilling within 600 meters were taken as the research object. The borehole is located in Alxa,Inner Mongolia,China. Using survey grid method and image processing technology,micrographs were translated into binaryzation image of micro cracks. Then,geometric parameters of the micro cracks（ such as quantity,width,cranny ratio,etc） were analyzed to describe the spatial distribution the micro cracks characteristics. The morphology characteristics and element content of micro cracks were analyzed by scanning electron microscopy energy dispersive X ray analysis（ SEMEDS）. The natural moisture content and CIA are two important parameters of chemical weathering in this study.Finally,Comprehensive evaluation was used to analyze granite integrity. The results show：（ 1） The complete granite samples＇ micro cracks development have a general trend from high to low as the sampling depth from shallow to deep in this study area.（ 2） Fissures are inclined to develop among feldspar and biotite. On the contrary,fissures are more commonly developed in quartz grains.（ 3） Cranny ratio,average gap width,fracture number and CIA become larger near broken zones.（ 4） The distance of fracture zone influence on the complete granite can be more than 10. 6 m.And the late hydrothermal seepage distance can be more than 50. 27 m.（ 5） Through comprehensive evaluation,

关 键 词：巴彦诺日公 花岗岩 微裂隙 发育特征 

分 类 号：P584[天文地球—岩石学]