基于高密度电阻率成像法的基岩裂隙网络原位识别试验研究

摘要

对于以低渗透性基岩为处置围岩的核废物地质处置库来说,基岩中的裂隙网络是地下水进入处置库和放射性核素从处置库向外界环境迁移的主要通道.因此,研究基岩内裂隙网络的空间分布特征,对核废物的地质处置是否安全具有十分重要的意义.本文以花岗岩为例通过野外试验,分析研究了利用高密度电阻率成像法(ERT),对处于不同状态条件下的基岩中裂隙网络进行三维原位识别的效果及能力.结果表明在以高阻值为主要电特性的基岩中,利用ERT对基岩中三维裂隙网络进行原位识别是可行的,并且裂隙的电阻率特征能较好的反映出裂隙的空间分布位置和形态,但对裂隙网络识别的效果与测线方向有关.%The fractures network in the bedrock are the main pathways for the ground water getting in and the radioactive nuclides escaping from the nuclear waste repository which was built in the low-permeability bedrock. So, it is very important to study the characters of the fractures networks to ensure the safety of the nuclear waste repository. The article analyzed the effects and abilities for using high-density Electrical Resistivity Tomography (ERT) to indentify the three-dimensional fractures networks in the different states bedrock in-situ, by the field experiments which were done in the granite. The results indicate that it is feasible to identify the fractures networks in the bedrock for which the electrical property is high-resistivity. And the resistivity around the fractures can reflect the positions of spatial distribution and the shapes of fractures very well. But the effects and abilities of recognizing the fractures networks are related to the measurements-direction.