【作者】 姜广辉； 左建平； 马腾； 魏旭；

【Author】 Jiang Guanghui;Zuo Jianping;Ma Teng;Wei Xu;School of Mechanics and Civil Engineering, China University of Mining and Technology;State Key Laboratory of Coal Resources and Safe Mining, China University of Mining and Technology;

【机构】 中国矿业大学(北京)力学与建筑工程学院； 中国矿业大学(北京)煤炭资源与安全开采国家重点实验室；

【摘要】 岩石受热前后物理力学性质变化的研究对地下仓库选址和地热资源开采等工程具有重要意义。本文以取自马峦山隧道的花岗岩为研究对象,经过不同温度处理后进行了质量、波速、渗透率的测量。从力学、声学、宏观、细观以及渗透性等各方面对高温对岩石特性的影响进行了分析研究。得到以下结论:(1)随着温度的升高,岩石的质量不断减小,岩石质量随温度的变化主要与岩石中的不同形态的水的逸出相关。(2)随着温度的升高,岩石的纵横波速逐渐降低。根据不同温度波速的变化情况将热开裂分为四个阶段:a.裂纹起始阶段,b.微裂纹加速发育阶段,c.裂纹转化阶段,d.裂纹继续发育阶段。(3)随着温度的升高渗透率在不断增加,且温度越高渗透率增加速度越快。(4)变异系数在波速各向异性的研究中的物理意义是反映裂隙结构特征的变化。裂隙结构在300℃前后发生了变化。300℃前以微裂纹结构全面发育为主;300℃以后以微裂纹联通扩展为宏观裂纹为主。(5)动弹性模量、动体积模量、动剪切模量、动泊松比等动态力学参数均随温度的升高而降低。(6)利用改进的波速-孔隙度的经验公式计算了不同温度下的孔隙度,孔隙度随温度的升高而增加。进一步通过Kozeny-Carman方程和改进的波速-孔隙度公式,建立了波速-渗透率模型,发现温度的变化改变了岩石的几何因子和颗粒粒径。最终对裂隙发育情况的分段分析,将温度变化引起的波速、变异系数和渗透率等的变化做了合理解释。更多还原

【Abstract】 Understanding the change of physical and mechanical property of rock before and after heating is of great significance for site selection of mattamore and exploitation of geothermal resources. In this paper, mass, wave velocity and permeability of granite specimen from Maluanshan tunnel were measured after high-temperature processing. The effect of temperature on rock properties in terms of mechanics, acoustics, macro-perspective, meso-perspective and permeability were measured and analyzed. The main conclusions are as follows:(1) The mass of granite decreases continuously with increase in temperature.(2) Both P and S wave velocities of granite decrease with temperature and thermal cracking occurs in three stages: cracks stabilization development stage, cracks accelerated development stage, cracks shift stage and cracks continued development stage.(3) The permeability of granite increases with increasing processing temperature.(4) The change of cracks structural feature in the study of wave velocity anisotropy can be correlated with coefficient of variables.(5) Parameters such as dynamic elasticity modulus, dynamic bulk modulus, dynamic shear modulus and dynamic Poisson’s ratio decrease with increasing temperature.(6) Porosity of granite under different temperatures are calculated using modified wave velocity-porosity empirical formula, and to show an increase with temperature. Furthermore, a new wave velocity-permeability model is established according to Kozeny-Carman equation and modified wave velocity-porosity empirical formula. The geometric factor and partial diameter of granite were found to be also affected by the processing temperature. This paper also carries out piecewise analysis on effect of development condition of cracks inthe change of wave velocity, coefficient of variation and permeability with temperature reasonably.更多还原