单轴压缩下冻融灰岩力学特性及裂纹扩展机理研究  

Study on Mechanical Properties and Crack Propagation Mechanism of Freeze-thaw Limestone under Uniaxial Compression

作　　者：王伟 任韬哲 候超 李达 杨光 WANG Wei;REN Taozhe;HOU Chao;LI Da;YANG Guang(Pumped Storage Technology and Economic Research Institute of State Grid Xinyuan Holdings Co.,Ltd.,Beijing 100030,China;School of Civil Engineering and Architecture,Henan University of Science and Technology,Luoyang 471000,China;State Key Laboratory of Shield Machine and Boring Technology,Zhengzhou 450001,China)

机构地区：[1]国网新源控股有限公司抽水蓄能技术经济研究院,北京100030 [2]河南科技大学土木建筑学院,河南洛阳471000 [3]隧道掘进机及智能运维全国重点实验室,河南郑州450001

出　　处：《金属矿山》2024年第10期61-68,共8页Metal Mine

基　　金：盾构及掘进技术国家重点实验室开放课题(编号:SKLST-2024-01);国网新源集团(控股)有限公司科技项目(编号:SGXYKJ-2022-050)。

摘　　要：为研究冻融灰岩的物理力学特性及受载破裂过程,基于单轴压缩和电镜扫描试验,获得了冻融环境下灰岩基本力学参数和微观形貌演化规律,并结合PFC2D颗粒流程序,分析了冻融灰岩在荷载作用下的微裂纹扩展和最大主应力场演化规律。结果表明:随着冻融次数的增加,灰岩的峰值强度和弹性模量均呈指数型递减,而损伤变量呈指数型递增;单次冻融循环作用下灰岩峰值强度和弹性模量的平均损伤率分别为0.58%和0.53%,对应的半生命周期分别为111.13和120.79次。灰岩受单向压缩荷载时拉—剪微裂纹占比最高,其次为拉伸和压—剪微裂纹,微裂纹演变趋势可分为无裂纹阶段、微裂纹缓慢发展阶段和微裂纹快速发展阶段。随着冻融次数的增加,微裂纹起裂应力、最大拉应力和压应力均呈指数型递减,表明试样的受载能力降低。研究成果有助于从多尺度认识冻融环境下灰岩的损伤特性和渐进破坏过程,为寒区岩体工程稳定性分析与控制提供理论依据。To study the physical and mechanical properties and loading fracture process of freeze-thawed limestone,the basic mechanical parameters and microscopic morphology evolution of limestone under freeze-thaw environment were obtained through uniaxial compression and scanning electron microscopy tests.Combined with the PFC2D particle flow program,the microcrack propagation and maximum principal stress field evolution of freeze-thawed limestone under loading were analyzed.The results show that as the number of freeze-thaw cycles increases,the peak strength and elastic modulus of limestone both decrease exponentially,while the damage variable increases exponentially.Under a single freeze-thaw cycle,the average damage rates of the peak strength and elastic modulus of limestone are 0.58%and 0.53%,respectively,with corresponding half life cycles of 111.13 and 120.79,respectively.When limestone is subjected to unidirectional compression load,the proportion of tensile-shear microcracks is the highest,followed by tensile and compressive-shear microcracks.The evolution trend of microcracks can be divided into no cracking stage,slow development stage of microcracks,and rapid development stage of microcracks.With the increase of freeze-thaw cycles,the initiation cracking stress,maximum tensile stress,and compressive stress decrease exponentially,indicating a decrease in the load-bearing capacity of the sample.The research results contribute to a multi-scale understanding of the damage characteristics and progressive failure process of limestone in freeze-thaw environments,and providing a theoretical basis for the stability analysis and control of rock and soil engineering in cold regions.

关 键 词：冻融环境 灰岩 损伤特性 数值模拟 裂纹扩展 

分 类 号：TD315[矿业工程—矿井建设]