摘要
岩体赋水性评价是高放废物地质处置库场址评价的关键研究内容之一,通常采用钻探并进行钻孔水文试验以获得岩石渗透率、地下水含量及分布等水文地质参数,然而,常规钻孔水文试验不适宜大面积高频次地覆盖整个选址区。为此,采用可直接探测地下水的地面核磁共振法对新场花岗岩体3个已知水文钻孔进行了赋水性评价试验,结果表明:地下水水位埋深位置表现为相对高的自由水含量,且其上部同时表现为相对高束缚水含量;裂隙水发育位置表现为同时具有高自由水异常和高束缚水异常;由核磁共振信号反演计算得到的最大渗透系数与全孔抽水试验获得的平均渗透系数在同一数量级,且核磁共振探测获得的岩石单位体积含水率为岩体地下水赋水性评价提供了定量参考。本次地面核磁共振探测试验结果与钻孔水文地质试验结果一致性好,有效揭示了地下水水位埋深、岩石渗透率、水量大小及裂隙水发育位置,地面核磁共振方法可有效应用于花岗岩体赋水性评价,为经济、快速且无损地获得岩体关键水文地质参数提供了有效技术手段。
Aquosity evaluation is one of the key study contents in site characterization of high level radioactive waste disposal repository,hydrogeological parameters such as rock permeability,groundwater content and distribution are usually obtained by drilling and borehole hydrological tests.However,borehole hydrogeological test in high frequency is not suitable to cover the entire repository.We carried an experimental study on aquosity evaluation in three boreholes of Xinchang granite with surface nuclear magnetic resonance(NMR)method which can directly detect groundwater.The experiment results found three facts:1)content of free water is relatively high at the buried depth of groundwater level,and the upper part of it is relatively high bound water content;2)the position of fissure water shows superposition of high free water anomaly and high bound water anomaly;3)the maximum permeability coefficient obtained from NMR signal inversion is of the same order of magnitude as the average permeability coefficient obtained from full-hole pumping test.The unit volume water content of rock obtained by nuclear magnetic resonance detection provided quantitative reference for groundwater content evaluation of the batholith.The NMR experiment effectively revealed the groundwater depth,rock permeability,water content and the location of crevice water which are in good agreement with the results of borehole hydrogeological test.Therefore the surface nuclear magnetic resonance method can be effectively applied to evaluate the aquosity of granite batholith,and provides an effective technical means to obtain the key hydrogeological parameters of granite pluton economically,rapidly and nondestructively.
作者
万汉平
张明
WAN Hanping;ZHANG Ming(Beijing Research Institute of Uranium Geology,Beijing 100029,China)
出处
《世界核地质科学》
CAS
2023年第2期331-338,共8页
World Nuclear Geoscience
关键词
高放废物处置库
新场岩体
地面核磁共振法
赋水性评价
high-level radioactive waste disposal repository
Xinchang granite pluton
surface nuclear magnetic resonance method
aquosity evaluation
