采动应力下煤体渗透率模型构建及研究进展

首先对煤体渗透率的经典模型进行了简介，其次结合采动过程中煤体内的力学变化机制及渗透率的控制因素提出了采动应力下煤体渗透率模型构建过程中的关键问题，并就每个关键问题的研究进展进行了总结和分析。关键问题包括以下3个方面:采动煤体各向异性特征、采动煤体损伤破裂特征和煤体吸附解吸特征的表征方法。其中，各向异性特征的煤体渗透率模型可划分为有效应力变化和几何参数变化进行表征的两类，有效应力变化角度的建模结果基本为指数型函数、几何参数变化角度的建模结果多为3次方的幂函数;损伤破裂特征的煤体渗透率模型被归纳为本构方程中含损伤变量和渗透率表达式中含损伤变量的2类，本构方程中含损伤变量的模型具有更广的适用范围，渗透率表达式中含损伤变量的模型能够更加直观的表示渗透率和影响因素之间的数量关系;在煤体吸附解吸特征的表征方法中对基于吸附热力学而建立的煤体吸附应变表达式进行了总结，同时指出在煤体渗透率模型构建中Langmuir方程形式的吸附应变表达式应用最为广泛。然后，对采动应力下煤体渗透率模型的研究进展进行了介绍，将采动应力下煤体渗透率模型归纳为有效应力型、几何参数型和系数拟合型的3类，依次对3类模型中代表性成果的表达式及应用情况进行了概述。最后，从每个关键问题的角度对后续构建采动应力下煤体渗透率模型的研究进行了展望。

Development in modeling approaches to mining induced permeability of coals

The classical permeability models of coal were briefly introduced.Based on the mechanical mechanism of coal and controlling factors of permeability in mining,the key problems in the process of constructing permeability model of coal under mining were put forward.The key problems include the anisotropic characteristic of coal,the damage and fracture of coal under mining,and the treatment of sorption and desorption.Meanwhile,the development of each key problem was summarized and analyzed.Among the key problems,the anisotropic coal permeability models can be represented as the variety of effective stress or geometric parameters.The models based on the variety of effective stress are exponential function,but the models based on the variety of geometric parameters are almost the power function of the third power.The damaged coal permeability models were classified into two categories.One was damage variables in a constitutive equation,the other was damage variables in permeability expressions.The models whose damage variables are in constitutive equation have a wider scope of application.And the models whose damage variables are in permeability expressions can more intuitively express the quantitative relationship between permeability and influencing factors.In the treatment of sorption and desorption,the expressions of adsorption strain derived from adsorption thermodynamics were summarized.The expression of adsorption strain in the form of Langmuir equation was most widely used in the construction of coal permeability model.Moreover,the established permeability models of coal under mining were introduced.The permeability models of coal under mining were classified into effective stress type,geometric parameter type and coefficient fitting type.Then the expressions and applications of representative model in each type were introduced.The suggestions for further research on establishing the permeability models of coal under mining were proposed.