高温三轴应力下石灰岩热膨胀特性演化规律  

Evolution of Thermal Expansion Characteristics of Limestone Under High-Temperature Triaxial Stress

作　　者：陈正男 冯子军[1,2] 阴伟涛 张超[1,2] CHEN Zhengnan;FENG Zijun;YIN Weitao;ZHANG Chao(College of Mining Engineering,Taiyuan University of Technology,Taiyuan,Shanxi 030024,China;Key Laboratory of In-situ Modified Mining Ministry of Education,Taiyuan University of Technology,Taiyuan,Shanxi 030024,China)

机构地区：[1]太原理工大学矿业工程学院,山西太原030024 [2]太原理工大学原位改性采矿教育部重点实验室,山西太原030024

出　　处：《矿业研究与开发》2023年第10期133-138,共6页Mining Research and Development

基　　金：山西省基础研究计划项目(202103021223071)。

摘　　要：石灰岩作为地下工程中常见的岩层,其热力耦合作用下热变形在核废料深层封存、煤炭地下气化、地热资源开发等高温地下工程中至关重要。利用伺服控制多功能三轴试验系统,研究了高温三轴应力状态下石灰岩热膨胀的演化规律。试验结果表明:高温三轴应力下实时升温过程中,三轴应力压缩裂隙闭合和抑制矿物颗粒膨胀,随着温度的升高微裂隙伴随不断的开闭竞争关系,石灰岩热应变曲线呈阶梯状,并随着静水压力的增大,热应变大小及阶梯波动逐渐减小。热力耦合作用下,由于石灰岩固体骨架在温度作用下发生热破裂和软化,高温阶段三轴应力对热膨胀系数抑制作用增强。500℃升温过程中石灰岩热膨胀平均系数存在阈值压力,当静水压力不小于25 MPa时,热膨胀系数显著衰减。Limestone is a common rock stratum in underground engineering,and its thermal deformation under thermal-mechanical coupling is very important in high-temperature underground engineering,such as deep storage of nuclear waste,underground coal gasification,geothermal resources development and so on.The evolution law of thermal expansion of limestone under high-temperature triaxial stress state was investigated by using servo control multi-function triaxial test system.The experimental results show that the triaxial stress compresses the fracture closure and inhibits the expansion of mineral particles during the real-time warming process under high-temperature triaxial stress,and the micro-fractures are accompanied by continuous opening and closing competition relationship with the increase of temperature,and the limestone thermal strain curve shows a step shape,and the thermal strain size and step fluctuation gradually decrease with the increase of hydrostatic pressure.Under the action of thermal-mechanical,the inhibition of thermal expansion coefficient is enhanced by triaxial stress at high temperature stage due to thermal fracture and softening of limestone solid skeleton under the action of temperature.There is a threshold pressure for the average coefficient of thermal expansion of limestone during the heating process at 500C.When the hydrostatic pressure is not less than 25 MPa,the coefficient of thermal expansion is significantly attenuated.

关 键 词：热力耦合 石灰岩 热膨胀 

分 类 号：TD315[矿业工程—矿井建设]