基于矿井物理模型构建的煤岩体相似材料物性参数分析

Analysis of physical parameters of materials similar to coal and rock mass based on geophysical model construction of mines

为研究煤岩层地质异常体的地球物理响应特征,本文基于矿井工作面煤岩层结构,构建煤岩隐蔽致灾异常体实体物理模型,并进行相似材料模拟实验。通过均质设计和正交设计方法,用煤粉、砂子和水泥对山西某矿区的煤层、顶板、底板、陷落柱和断层的相似材料配比及其波速、电阻率、介电常数等物性参数进行了实验测试。研究结果表明材料对物性参数的影响规律如下:相比于煤粉和砂的含量,水泥含量是影响波速的主要因素;介电常数与电阻率受材料含水性的影响较高,含水率越高电阻率及介电常数呈降低趋势,实验测得的地质结构物性参数响应特征与其实际地球物理响应规律基本一致。实验数据、煤岩样和原位探测结果对比分析可知,各地质结构单元的最佳充填配比如下:煤层配比选用煤粉、砂和水泥含量为61.11%、11.11%和27.78%;顶板选择砂胶比2:1,石膏水泥比2∶8;底板选择砂胶比3:1,石膏水泥比4:6;断层选用砂75%、石膏10%、水泥15%;陷落柱选用砂66.7%、石膏6.67%、水泥26.6%。本次重点研究了各种地质构造物理模型的材料配比及其物理性质,可为后续模型构建提供数据支撑,对地球物理方法的应用及技术示范提供了良好的实验平台。

This paper constructs a geophysical model of hidden disaster-causing anomalies in coal rock for simulation experiments based on the structural design of coal rock seams at the mine working face to study the geophysical response characteristics of geological anomalies in coal rock seams.The material ratio and petrophysical parameters of the coal seam,roof,floor,collapse column,and fault in a mining area in Shanxi were tested using homogeneous and orthogonal test methods,and their petrophysical parameters,such as Vs,Vp,resistivity,permeability,and dielectric constant,were obtained.The coal dust and sand–cement contents are the main factors affecting the wave velocity,whereas the dielectric constant and resistivity are highly influenced by the water content of the material.The response characteristics of the petrophysical parameters of various types of geological structures measured via experiments are consistent with the corresponding geophysical responses of actual geophysical exploration methods.The experimental data were comparatively analyzed with the original coal rock samples and field in-situ probing results,and the best construction ratios of each geological structural unit were as follows:coal seam ratios of 61.11%,11.11%,and 27.78%were selected for coal dust,sand,and cement content,respectively;sand–cement and gypsum–cement ratios of 2:1 and 2:8,respectively,were selected for the roof;and sand–cement and gypsum–cement ratios of 3:1 and 4:6,respectively,were selected for the floor.The optimal ratios of 75%sand,10%gypsum,and 15%cement were chosen for the fault;those for the collapse column were 66.7%sand,6.67%gypsum,and 26.6%cement.This study focuses on the ratios of various geotectonic physical models and their physical properties,it provides data support for subsequent model construction and a good experimental platform for the demonstration of various geophysical exploration methods and techniques.