基于钻孔雷达与数字摄像的深部岩体精细探测基础研究

The core drilling is now the main method in geotechnical engineering surveying and detecting rock mass structure of underground, but cannot meet surveying and researching requirements on deep underground rock mass in major state construction projects with disadvantages of heavy workload, taking long time, high costing, single means and single logging data. Nowadays, the detailed detection and description on rock mass structure in target area are the key issue of construction security in major geotechnical projects and newly developing industries, such as underground energy development and storage, underground storage of carbon dioxide. Development of a more effective, accurate and integrated technique testing and analyzing underground rock structural features will be great engineering significance. The two most advanced methods today, borehole radar and digital panoramic borehole camera system will be combined and applied to engineering geological exploration in this project, to research the interpretation, processing and analysis methods jointing borehole radar signals with digital panoramic borehole image data, to research the image features of virtual core and the geometric parameters and spatial distribution of discontinuities, the rock quality evaluation method based on the virtual core, and the extension and the connectivity of discontinuities based on the borehole radar and digital imaging, the dielectric constant estimation and analysis methods involving different engineering geological survey methods. Test the feasibility and applicability of the method and extend the method to the practical engineering applications to enhance utilized ability of ground penetrating radar and to form a fast, accurate, advanced detection means of deep underground rock mass.

岩土工程地质勘察、地下深部岩体结构探测主要以机钻为主，工作量大，时间长，费用高，手段和信息单一，不能满足地下深部区域岩体调查与研究需要；而目前一些重大岩体工程和新兴行业，如地下深部能源开采与储藏和二氧化碳地下深层埋藏等，都要求对目标区域内的岩体结构进行精细探测与描述，传统钻探技术和方法已不能满足复杂地质结构精细探测要求；发展更为有效、精确的地下岩体综合探测分析技术有重大工程意义。 本项目研究拟将钻孔地质雷达与钻孔数字成像相结合应用于工程地质勘察，围绕基于钻孔雷达与数字摄像的深部岩体精细探测基础研究关键理论和技术问题，开展复杂地下岩体结构探地雷达图像信号特征、虚拟岩芯的图像特征、岩体结构面连通性和延展性，以及基于虚拟岩芯的岩石质量评价方法和介电常数估算分析方法等几个方面的研究，为构建综合精细探测技术奠定理论技术基础。

本项目针对虚拟岩芯的图像特征及其结构面的分布、产状、正弦曲线形态、基于虚拟岩芯的岩石质量评价方法、岩体结构面连通性和延展性等几大研究目标，研究了典型虚拟岩芯图像及判释方法，结合钻探获得的实际岩芯，归纳这些以往工程项目中常见的虚拟岩芯图像在岩石颜色、纹理特征、颗粒大小和排列方式方面的表现。研究了相邻钻孔数字图像的岩体结构面延展性问题，推导了两两相邻钻孔结构面连通所应满足的条件，研究了结构面深度位置相关性的计算方法，并提出通过结构面两侧岩石颜色、纹理特征、岩石颗粒大小和排列方式等岩石特征以及结构面形态和充填情况，来判断是否为同一岩体结构面的延伸。研究了基于虚拟岩芯结构面几何参数变化的修正岩石质量评价方法。分析了面状不良地质体钻孔雷达反射截面特征，提出了基于钻孔地质雷达与数字钻孔摄像的岩土介电常数估算方法。通过数值实验和物理试验方法，研究了纹理结构面对岩体力学性质的影响。