石英-绿帘石化的蚀变特征及工程特性研究  

ANALYSIS ON PROPERTY OF QUARTZ-EPIDOTIZATION ALTERATION AND ITS ENGINEERING CHARACTERISTICS

作　　者：苗朝[1,2] 沈军辉[3] 石胜伟[1,2] 

机构地区：[1]中国地质调查局地质灾害防治技术中心,成都611734 [2]中国地质科学院探矿工艺研究所,成都611734 [3]地质灾害防治与地质环境保护国家重点实验室(成都理工大学),成都610059

出　　处：《工程地质学报》2016年第5期907-914,共8页Journal of Engineering Geology

基　　金：国家自然科学基金项目(41572308)资助

摘　　要：针对大岗山水电站坝区石英-绿帘石化蚀变问题，在系统调研和室内试验基础上探讨了石英-绿帘石化蚀变带的地质特征、矿物学特征及物理力学性质。研究表明，花岗岩体中SN/E∠17°～26°缓倾角错动带常发育由动力变质作用形成的石英-绿帘石相蚀变，错动面常发育擦痕、阶步。蚀变产生了绢云母、绿泥石、绿帘石和方解石等软弱矿物，含量在18%左右，化学分析显示其成分变化不大。物理力学试验显示：蚀变岩石物理水理和强度特性有一定程度的弱化，天然和饱和抗压强度损失率为8.3%和5.9%。蚀变产生的石英和绿帘石对结构面的抗剪强度产生一定影响，现场直剪试验表明结构面抗剪（断）强度明显降低。研究成果具有一定创新性，对石英-绿帘石化蚀变的工程影响和处理提供参考。Quartz-epidotization alteration is an important geological problem in Dagangshan hydropower station. Taking into account the advantage of geological survey and laboratory experiment, this paper analyses its geological distribution, mineralogical and structural characteristics and physical and mechanical properties. The study reveals that ranite in SN/E∠17°-26° low-angle shearing belts often develops quartz-epidotization alteration formed by the dynamic metamorphism, which always grows scratches and order step. Alteration produces sericite, chlorite, epidote and calcite weak mineral content of about 18%. Chemical analysis shows little change in its composition. Physical and mechanical tests show that the physical and water properties and strength characteristics of altered rock have a certain degree of weakening, natural and saturated compressive strength loss rate of 8.3% and 5.9%. Quartz and epidote produced by alteration have an impact on the shear strength of the structure. In-situ direct shear tests show shear intensity decreases. Research has some innovative, can be a reference on engineering impact and process of quartz-epidotization alteration.

关 键 词：石英-绿帘石化 蚀变特征 工程特性 蚀变矿物学特征 物理力学特性 

分 类 号：P584[天文地球—岩石学]