摘要
我国高放废物地质处置库首选预选区位于甘肃北山南缘,区内分布有多条大型非活动断裂构造,这些断裂很可能成为未来放射性核素迁移的主要通道。断裂在向地表延伸过程中,受第四系覆盖等因素影响,造成关键构造部位隐伏地下而难以识别。本文以北山地区新场地段南部红旗山和前红泉断裂为研究对象,采用土壤中氡气测量方法,探讨了大型断裂构造中隐伏段落的识别及其指示的水文地质意义。结果表明:土壤中氡气测量对于识别北山南缘隐伏断裂具有很好的指示意义,是传统地质调查方法的一种重要补充;红旗山和前红泉断裂裂隙系统整体开启性均较差,裂隙系统不发育,影响范围较小,不具备形成较大规模储水空间的可能性。不同断裂带土壤氡浓度背景值差异较大,可根据土壤氡浓度累积频率分布图确定背景值;土壤氡浓度等值线分布图对判断隐伏断裂位置具有一定的指示作用。对于压剪性断裂而言,主断裂多沿氡气高异常与低异常边界分布或表现为氡气中等异常,而两侧的次级断裂表现为氡气高异常。
The preferred area for high-level radioactive waste(HLW)geological disposal repository in China is located in the southern margin of the Beishan area,Gansu Province.There are many large-scale non-active faults in the area.These faults likely provide the dominant pathways for groundwater(GW)flow.In the process of extending to the surface,some key parts are hidden underground and difficult to identify due to Quaternary coverage and other factors.In order to identify the hidden parts in large-scale faults and its hydrogeological significance,experimental sites were selected located in the south of Xinchang site in the Beishan area,namely the Hongqishan and the Qianhongquan faults.The soil radon concentrations were obtained in both these faults.The results suggest that measuring radon concentrations in surface soil is useful for identifying the hidden faults in this region,and is an important supplement to the traditional geological survey method.The opening of the fracture networks of the two fault zones is undeveloped,and the damage zone is small.There is a high possibility of forming large-scale GW storage space.The background values of soil radon concentration in different fault zones are quite different,which could be due to the cumulative frequency distribution of soil radon concentration.The contour distribution map of soil radon concentration can indicate the location of hidden faults.For the compression shear faults,the main faults are mostly distributed along the boundary between high and low radon anomalies or show medium anomalies,while the secondary faults on both sides show high anomalies.
作者
李杰彪
周志超
云龙
苏锐
郭永海
LI Jiebiao;ZHOU Zhichao;YUN Long;SU Rui;GUO Yonghai(CAEA Innovation Center for Geological Disposal of High-Level Radioactive Waste,Beijing Research Institute of Uranium Geology,Beijing 100029,China)
出处
《地质学报》
EI
CAS
CSCD
北大核心
2022年第6期2240-2250,共11页
Acta Geologica Sinica
基金
高放废物地质处置(编号[2017]1405号)资助的成果。
关键词
氡气测量
隐伏断裂
水文地质
高放废物地质处置
北山地区
radon measurement
hidden fault
hydrogeology
high-level radioactive waste geological disposal
Beishan area
