静力压缩下煤岩组合体的裂前宏观弹性模型

煤岩组合体在静力压缩下的宏观变形受界面效应影响，与煤、岩单体存在显著差异。在岩石单体材料的有效介质模型基础上进行改进，考虑了煤岩组合体的构成特征，提出一种适用于不同类型的煤岩组合体的裂前宏观弹性模型。模型参数基于轴向裂纹应变确定，均可从试验曲线获得，方法简单方便。通过现有文献的数据验证，表明了模型的合理性、有效性和普适性。对模型参数进行讨论，结果表明：（1）在煤岩组合体的裂前阶段，煤岩组合体裂纹差异可以忽略；（2）模型通过对煤岩组合体基质进行解耦，反映了界面效应对煤岩组合体弹性性能的影响；（3）模型中岩体基质的有效占比随着煤体比例的提高显著下降；（4）存在岩体与煤体弹性模量的最佳比值，使岩体基质的有效占比最大。模型可为矿井支护方案设计与材料选择提供一种新的思路。

A macroscopic elastic model of coal-rock combined body under static compression before cracking

Affected by the interface effect, the macroscopic pre-cracking deformation of coal-rock combined body under static compression is significantly different from the coal and rock single body. Based on the effective medium model of rock-like material, this paper considers the composition characteristics of the coal-rock combined body, and proposes a pre-cracking macro-elastic model suitable for different types of coal-rock combined body. The parameters obtained from the test curve are determined by the axial crack strain, which is simple and convenient. The data verification of the existing literature shows the rationality, validity and universality of the model. Moreover, the model parameters are discussed and the following conclusion are obtained: (1) The micro-crack difference can be ignored in the pre-cracking stage of coal-rock combined body. (2) By decoupling the matrix of the coal-rock combined body, the model reflects the impact of interface effect on the elastic modulus of the coal-rock combined body. (3) The effective proportion of the rock matrix decreases significantly with the increase of the coal proportion. (4) There is an optimal ratio of elastic modulus of rock body to coal body, which maximizes the effective proportion of rock matrix. This model can provide a new perspective for mine support scheme design and material selection.