介绍当前地球物理测井技术在煤矿岩体工程勘察领域的应用现状,剖析GSR的基本原理和分析方法,指出GSR是以声波测井数据为基础,并从地质力学的角度考虑各种因素(如矿层、裂隙等)对波速的影响;强调GSR不是要评估岩体的强度,相反,它是提供一种对岩体性质进行定量、综合的评估方法。使用的测井类型分别为声波测井、伽玛测井和密度测井。工程实践表明,地球物理测井方法在识别岩体内部的性质及变化规律方面,有其自身的优势,尤其是在软岩区域圈定、关键层识别、底板突水危险区勘察方面,具有直观、定量表述的优越之处:GSR与单轴抗压强度的对比结果证明,“单一岩体强度指标反映岩体性质”有一定的局限性,GSR的结果更符合现场情况;三维地震勘探与GSR的耦合分析方法,为对钻孔之间的“盲区”探查提供了有益的帮助,是原位探测隔水关键层的有效方法。最后提出基于地球物理技术的“矿山岩体性质原位研究”的基本思路,即利用测井技术对矿山岩体性质进行开采前的三维“静态定量”描述;借助于微震、电磁辐射等监测技术,在煤矿开采过程中对岩体破坏规律的三维“动态定量”描述。
The current application of geophysical logging technique to the investigation of rock mass engineering in coal mine, especially the geophysical strata rating(GSR), is introduced. GSR is mainly based on sonic logging data(density and gamma logs are used simultaneously): and the formulation relies on a geomechanical understanding of the factors(bedding or fracture) that influence sonic velocity, and does not attempt to estimate rock strength, rather to provide a method for estimating the quality of rock mass quantificationally and comprehensively. Engineering practice indicates that geophysical logging technique with its innate ability has been playing a helpful role in quantitatively identifying the rock mass quality and changes in rock mass, such as delineating the range of soft rock, recognition of key strata, and exploration of potential regions of water inrush. It also comes to the conclusion by comparison that GSR is more reliable than uniaxial compressive strength which is used only in quantitative description of sedimentary rock. Seismic prospecting is also employed to bridge the gap among boreholes and is helpful to understand what is going on there. A new academic thought of geophysically quantitatively describing rock mass quality, namely, it is possible to statically quantitatively describe the rock mass with geophysical logging technique before mining, and dynamically quantitatively describe the rock strata movements associated with mining during retreating with microseismic monitoring or electromagnetic radiation.