冰充填裂隙对冻结岩体压缩破坏特征的影响研究  

Study on the effects of the ice-filled fissure on the failure features of frozen rock mass

作　　者：赵涛[1] 冯云枫 贾海梁[1] 唐丽云[1] 李国玉 ZHAO Tao;FENG Yunfeng;JIA Hailiang;TANG Liyun;LI Guoyu(College of Architecture and Civil Engineering,Xi’an University of Science and Technology,Xi’an 710054,China;Northwest Institute of Eco-Environment and Resources,Chinese Academy of Sciences,Lanzhou 730000,China)

机构地区：[1]西安科技大学建筑与土木工程学院,陕西西安710054 [2]中国科学院西北生态环境资源研究院,甘肃兰州730000

出　　处：《冰川冻土》2024年第4期1246-1258,共13页Journal of Glaciology and Geocryology

基　　金：国家自然科学基金项目(42271148)资助。

摘　　要：冻结岩体的力学性质是决定冻结地层工程施工与运营安全的核心因素,而冻结岩体的力学性质由裂隙结构和冻结温度等条件决定。本文在常温和冻结条件下开展了含预制裂隙砂岩的力学实验,通过高速摄影技术对试样表面的裂纹起裂和扩展过程进行了监测,基于实验结果着重讨论了冰充填裂隙对冻结岩体压缩破坏特征的影响机制。结果表明:(1)冻结没有改变试样强度随裂隙倾角的变化趋势,随裂隙倾角的增大,试样的强度均呈先减后增的趋势。强度最小值出现在裂隙倾角α=60°时,最大值出现在α=90°时;(2)在冻结状态下,试样的起裂模式随裂隙倾角的增加整体呈现“拉伸起裂→剪切起裂→拉伸起裂”的变化趋势,此外,相同裂隙倾角的试样在冻结状态下起裂的应力水平均高于在常温状态下;(3)冻结裂隙砂岩的力学性质受冻结作用和裂隙倾角双重控制。并进一步分析了冰填充裂隙对冻结岩体压缩破坏特征的影响,认为冰均起到了支撑、填充和黏结作用。在裂隙倾角较小时(0°~30°),裂隙冰的法向压力较高,强化效应主要来源于冰的支撑作用;当裂隙倾角较大(45°~75°)时,裂隙冰上的法向压力较低,强化效应主要来源于冰-岩界面黏结作用;裂隙倾角(近90°)与加载方向平行时,裂隙冰的法向应力变为拉应力,强化效应主要来源于冰-岩界面黏结作用。With the promotion of the Belt and Road initiative,strategic corridors are being developed in the western cold regions,necessitating numerous tunnel and slope projects in frozen rock formations.The mechanical properties of frozen rock are pivotal for ensuring the safety of construction and operation in such environments,influenced by factors like fracture structure and freezing temperature.However,the impact of fracture structure on the mechanical behavior of frozen rock masses remains poorly understood,particularly the role of fracture ice during rock mass failure.This study aims to elucidate the effects of fracture structure on the mechanical properties of frozen rock masses and the mechanism of ice fractures in the failure process.We selected medium and coarse-grained saturated yellow sandstone as our research subject and conducted uniaxial compression failure tests on sandstone samples with varying fracture dip angles(α=0°,15°,30°,45°,60°,75°,90°)at freezing(-10℃)and room temperature(25℃)conditions.We analyzed the variation in mechanical properties of frozen sandstone under different fracture dip angles and discussed the influence mechanism of fracture dip angle on crack propagation based on the principle of ice-rock interaction.The findings indicate that:(1)Freezing does not change the trend of strength and elastic modulus variation with fracture inclination.Both parameters show a decreasing-then-increasing pattern as the fracture angle increases,with minima atα=60°and maxima atα=90°.(2)The initiation pattern of samples follows a“tensile cracking→shear cracking→tensile cracking”trend at both room temperature and frozen states,with higher stress levels required for crack initiation in the frozen state.(3)The mechanical properties of frozen fissured sandstone are governed by both freezing effects and fracture inclination angles,with changes in fracture angle altering the stress state at the fissure tips and ice-rock interactions affecting fracture initiation and propagation.(4)At smalle

关 键 词：冻结岩体 夹冰裂隙 起裂与扩展 冰-岩界面 冻结强化 

分 类 号：TU45[建筑科学—岩土工程] P642.14[建筑科学—土工工程]