高放废物地质处置阿拉善预选区巴彦诺日公地段目标深度岩体质量预测

Prediction of Rock Mass Quality at Target Depth for the Bayannuorigong Section of the Alxa Pre-Selected Region for Geological Disposal of High-Level Nuclear Waste

高放废物地质处置阿拉善预选区巴彦诺日公地段位于阿拉善地块东部,主要由二叠纪花岗岩构成,地壳次稳定。通过踏勘,确定了2个钻孔,布置了若干条物探剖面。以这2个钻孔为中心,在17km×17km范围内进行了工程地质测绘,获得了地表结构面分布特征。地表岩体质量以Ⅲ级岩体为主,地表以下3m^4m处多为Ⅰ级和Ⅱ级岩体。根据钻孔岩心编录和力学试验数据,对岩心质量进行评价,岩心整体质量较好,以Ⅰ级和Ⅱ级岩体为主。对比岩体质量和测井数据,发现岩体质量与岩体的物理参数具有明显的相关性。通过和CSAMT剖面上对应位置的对比,建立了岩体质量与电阻率的关系。结合地表岩体质量、钻孔岩心质量和物探剖面,对目标深度岩体进行了预测:目标深度(600m深左右)岩体质量以Ⅰ级岩体为主,局部有Ⅱ级岩体和Ⅲ级岩体。

The Bayannuorigong section of the Alxa pre-selected region for geological disposal of high-level nuclear waste is located in the eastern Alxa block,where the crust consists of Permian granite with sub-stability. According to reconnaissance,two boreholes and some geophysical survey lines were deployed. And engineering geological mapping was carried out in a 17km×17km range to probe the distribution of discontinuities. The surface rock mass is dominated by grade Ⅲ,and 3~4m below the surface is mostly grades Ⅰ and Ⅱ. According to core logging and mechanical tests,the drill cores are categorized as types Ⅰ and Ⅱ. Comparison of rock mass quality and well logging data shows an obvious correlation between quality and physical parameters of the rock mass. Therefore,the relationship between rock mass quality and resistivity can be established. Combining with the quality of surface rock mass and drilling cores and geophysical prospecting profiles,the quality of rock mass at the target depth has been predicted:rock mass is dominated by grade I,and some are of grades Ⅱ and Ⅲ.