摘要
针对传统水库工程地质勘察方法存在的周期长、成本高的问题,在拉院水库工程地质勘察中,创新采用了“物探先行,钻探验证”的勘察思路。采用激发极化法勘察库区左岸山脊的地下水分布状况:首先根据测区出露泉点的高程,标定供电极距与探测深度的关系为H=AB/5;随后依据视电阻率剖面图判定含水层岩体视电阻率总体小于500Ω·m;再通过半衰时数据曲线确定含水层岩体半衰时参数大于1100 ms;最后根据含水异常曲线特征确定地下水位深度。应用大地电磁测深法勘察库区岩性分布状况,结果显示不同岩性地质体的视电阻率差异显著:砂泥岩及河床处含水率较高的岩体视电阻率总体小于200Ω·m,而灰岩和侵入岩的视电阻率总体大于200Ω·m;其中灰岩视电阻率呈团状不连续分布,侵入岩视电阻率则表现出深部宽、浅部尖的特征。在物探成果基础上针对性布设勘探钻孔,并利用钻探验证物探效果。通过对比钻孔揭示的地下水位及地层岩性分布,认为激发极化法对地下水位的识别能力较强,大地电磁测深法在地层岩性勘察方面效果显著。该综合物探成果为精细化布孔提供了可靠依据,显著节约了钻探成本,缩短了勘察周期,表明综合物探技术在水利工程地质勘察中具有广阔的应用前景。
This work attempts to address the issues of long cycles and high costs associated with traditional reservoir engineering geological investigation methods.Taken the Layuan reservoir as a case study,an innovative investigation approach of"geophysical prospecting first,drilling verification second"was adopted in the engineering geological investigation of the Layuan Reservoir.The induced polarization method was applied to investigate the groundwater distribution in the left bank ridge of the reservoir area.First,based on the elevation of exposed spring points in the survey area,the relationship between the supply electrode distance and the detection depth was calibrated as H=AB/5.Subsequently,based on the apparent resistivity profile,it was determined that the overall apparent resistivity of the aquifer rock mass was less than 500Ω·m.Then,through the half-decay time data curves,it was confirmed that the half-decay time parameter of the aquifer rock mass was greater than 1100 ms.Finally,the groundwater level depth was determined according to the characteristics of the water-bearing anomaly curves.The magnetotelluric sounding method was applied to investigate the lithology distribution in the reservoir area.The investigation results show that the apparent resistivity of different lithological geological bodies differed significantly.The overall apparent resistivity of sandstone-mudstone and rock masses with high water content at the riverbed was less than 200Ω·m,while that of limestone and intrusive rocks was greater than 200Ω·m.Among these,the apparent resistivity of limestone rock mass exhibited a clustered and discontinuous characteristic,and that of intrusive rock mass exhibited a characteristic of being broad at depth and sharp shallowly.Based on the geophysical prospecting results,exploration drill holes were strategically placed,and drilling was used to verify the geophysical prospecting effect.By comparing the groundwater level depth and stratigraphic lithology distribution revealed by the drilling,it is inferred that the induced polarization method has strong capability in identifying groundwater levels,and the magnetotelluric sounding method has significant effectiveness in investigating stratigraphic lithology distribution.These integrated geophysical prospecting results provide a reliable basis for refined drillhole deployment,and greatly save drilling investigation costs and shorten the investigation cycle.It is indicated that the integrated geophysical prospecting method has broad application prospects in hydraulic engineering geological investigation.
作者
高正
米健
罗安华
李德春
李靖
朱加兵
王连培
胡涛涛
GAO Zheng;MI Jian;LUO Anhua;LI Dechun;LI Jing;ZHU Jiabing;WANG Lianpei;HU Taotao(Yunnan Water Resources and Hydropower Survey and Design Institute Co.,Ltd.,Kunming,Yunnan 650051;Yunnan Institute of Water&Hydropower Engineering Investigation Design and Research,Kunming,Yunnan 650051)
出处
《地质与勘探》
2025年第5期1025-1032,共8页
Geology and Exploration
关键词
大地电磁测深
激发极化法
电阻率
半衰时
侵入岩
拉院水库
magnetotelluric sounding
induced polarization method
resistivity
half-decay time
intrusive rock
Layuan reservoir
作者简介
第一作者:高正(1990年-),男,2019年毕业于昆明理工大学,矿产普查与勘探专业获硕士学位,工程师,主要从事水利水电工程地球物理勘察工作。E-mail:349502136@qq.com;通讯作者:米健(1982年-),男,2007年毕业于武汉理工大学,岩土工程专业获硕士学位,正高级工程师,主要从事水利水电工程地质相关研究工作。E-mail:mijian2000@qq.com。
