工程地质学报2024，Vol.32Issue(6)：2152-2165,14.DOI:10.13544/j.cnki.jeg.2023-0383
湖南福寿山蚀变花岗岩的工程地质特征及其蚀变程度评价
ENGINEERING GEOLOGICAL CHARACTERISTICS AND ALTERATION DEGREE EVALUATION OF ALTERED GRANITE IN FUSHOU MOUN-TAIN,HUNAN PROVINCE
摘要
Abstract
Granite is often selected as a foundation for dams due to its good physical and mechanical properties.However,hydrothermal alteration induces significant changes in the mineral composition,structure,texture,chem-ical constituents,and physico-mechanical properties of deep-seated rocks.Therefore,the study of hydrothermal al-teration characteristics in deep-seated granite holds paramount significance for hydraulic engineering constructions.The case of the Pingjiang Pumped Storage Power Station reservoir area in Hunan Fushou Mountain exhibits wide-spread exposure of Late Mesozoic granite.The main rock type is monzogranite.Surveys have indicated varying de-grees of argillization and chloritization within the granite,showing evident zonation of alteration intensity.In this re-search,an investigation is undertaken into the mineralogical composition,geochemical constituents,and mechani-cal indicators of granite rocks manifesting diverse degrees of hydrothermal alteration.The study reveals intense chlo-ritization of biotite in Fushou Mountain granite and feldspar altering into clay minerals,with the highest content reaching 30％to 40％,primarily consisting of kaolinite and montmorillonite.As the depth from the adit entrance in-creases,there is a discernible trend of diminishing weathering intensity in the granite.Moreover,the process of deep-seated rock alteration is primarily governed by the presence of structural planes,which subsequently gives rise to the development of alteration zones with a defined width on either side of these planes.The mechanical properties of highly weathered granite deteriorate significantly.With an increase in the depth of the adit,the mechanical prop-erties of the rock exhibit a strengthening trend with reduced weathering intensity.However,noticeable reductions occur within the hydrothermal alteration zones.Silicification enhances the point load strength of rocks while simulta-neously causing a considerable decrease in longitudinal wave velocity and rebound value.Field observation,scan-ning electron microscopy,and quantitative indices calculated by weight analysis were used to evaluate the alteration classification.The method used to evaluate the effect of alteration degree on Fushou Mountain granite provides a sci-entific basis for the construction of a pumped storage power plant.关键词
蚀变花岗岩/风化作用/热液蚀变/工程地质特征/蚀变程度评价Key words
Altered granite/Weathering/Hydrothermal alteration/Engineering geological characteristics/Alter-ation degree evaluation分类
天文与地球科学引用本文复制引用
任明浩,邓雅丽,袁广祥,董金玉,王洪建,赵菲,黄志全..湖南福寿山蚀变花岗岩的工程地质特征及其蚀变程度评价[J].工程地质学报,2024,32(6):2152-2165,14.基金项目
河南省重点研发专项(资助号:221111321500),国家重点研发计划项目(资助号:2019YFC1509704),国家自然科学基金项目(资助号:41803033),华北水利水电大学硕士创新能力提升工程项目(资助号:NCWUYC-202315081).This research is supported by the Key Research and Development Project of Henan Province(Grant No.221111321500),National Key R&D Pro-gram of China(Grant No.2019YFC1509704),National Natural Science Foundation of China(Grant No.41803033)and Master's Innovation Ca-pacity Enhancement Project of North China University of Water Resource and Electric Power(Grant No.NCWUYC-202315081). （资助号:221111321500）
