山西垣曲抽水蓄能电站上水库粘土质砂岩工程特性研究

Engineering Characteristics of Clay Sandstone in Upper Reservoir of Yuanqu Pumped-storage Power Station in Shanxi Province

在山西垣曲抽水蓄能电站上水库勘察过程中,多个基岩钻孔出现砂状岩芯,出露深度不一,厚度不等,初期给地质人员对地层岩性认识造成了较大困扰.经过钻孔声波测试、孔内数字成像观察、矿物成分、化学成分分析和地表地质测绘层位对比等多种手段,确定砂状岩芯原岩为含高岭石赤铁矿胶结砂岩(粘土质砂岩),成层分布,有一定的抗压强度,但强度较低.该粘土质砂岩对工程影响较大,勘察过程中分析了砂状岩体的成因及存在的工程地质问题,类比南方红层软岩的研究成果,并通过声波数据估算其单轴抗压强度,为工程设计提供合理的建议.

During the investigation of the upper reservoir of Yuanqu Pumped Storage Power Station in Shanxi Province, sandy cores appeared in many bedrock boreholes with different outcropping depths and thicknesses.It has caused great trouble to geologists in their understanding of stratigraphic lithology in the early stage.Through borehole acoustic testing, borehole digital imaging observation, mineral composition, chemical composition analysis and surface geological mapping horizon comparison and other means, it is determined that the original rock of sandy core is kaolinite-bearing hematite cemented sandstone(clayey sandstone).It has a certain compressive strength, but the strength is low.The clayey sandstone has a great influence on engineering. In the process of investigation, the causes of sandy rock mass and its engineering geological problems are analyzed, and the research results of red beds soft rock in south China are analogized. The uniaxial compressive strength of the sandstone is estimated by acoustic data, which provides reasonable suggestions for engineering.