摘要
随着人工地层冻结工程施工深度和极地冰盖钻探深度的不断增大,早期无压冻结冰力学性质研究成果与现场实测数据之间的偏差逐渐增大。为探究卸载条件下深部高压冻结冰力学特性,开展了10,20,30和50 MPa冻结压力下冰试样卸围压试验研究,并对其宏、细观变形破坏机制进行了观测与分析。研究结果表明:卸围压条件下,各工况冰试样偏应力-轴向应变曲线均表现出较长的屈服平台,峰值偏应力与残余偏应力随冻结压力呈先增大后减小的趋势,20 MPa冻结压力具有临界特性;宏观层面,随着冻结压力的增大,冰体韧性增强,变形破坏后试样由裂纹交错状转为高透明状;细观层面,微裂纹和动态再结晶是冰体卸围压变形破坏后的两大典型组构特征,变形破坏过程随冻结压力的增大逐渐由微裂纹发育主导转化为动态再结晶主导。研究成果可为深部人工冻结工程中冻结壁设计和极地巨厚冰盖钻探工艺改进提供理论依据。
With the continuous increase in the construction depth of artificial ground freezing projec and the drilling depth of polar ice sheets,discrepancies between nearly y research findings on the mechanical properties of pressure-free frozen ice and field-measured data has gradually widened.Aiming at exploring the mechanical characteristics of deep high-pressure frozen ice under unloading conditions,this study conducted confining pressure unloading tests on ice specimens under freezing pressures of 10,20,30,and 50 MPa,and observed and analyzed their macro-micro deformation and failure mechanisms.The following research results were obtained:Under confining pressure unloading conditions,the deviatoric stress-axial strain curves of ice specimens under all test conditions present a relatively long yield platform.Both the peak deviatoric stress and residual deviatoric stress initially increase and then decrease with the rise of freezing pressure,20 MPa being the critical freezing pressure.Macroscopically,as the freezing pressure rises,the ice becomes more ductile,and the ice specimen transitions from an interlaced crack pattern to a highly transparent appearance after deformation and failure.Microscopically,microcrack development and dynamic recrystallization emerge as two dominant fabric characteristics of ice after confining pressure unloading deformation and failure.As the freezing pressure rises,the deformation and failure process gradually shifts from being dominated by microcrack development to being dominated by dynamic recrystallization.The research findings can provide a theoretical foundation for both the design of freezing walls in deep artificial freezing projects and the optimization of drilling techniques for thick polar ice sheets.
作者
张雨
杨维好
杨志江
丁莹
张宸毅
孙培鑫
王宝生
于庆博
邹成
ZHANG Yu;YANG Weihao;YANG Zhijiang;DING Ying;ZHANG Chenyi;SUN Peixin;WANG Baosheng;YU Qingbo;ZOU Cheng(School of Mechanics&Civil Engineering,China University of Mining and Technology,Xuzhou,Jiangsu 221116,China;State Key Laboratory of Intelligent Construction and Healthy Operation and Maintenance in Deep Undergroud Engineering,China University of Mining and Technology,Xuzhou,Jiangsu 221116,China;Shanghai Foundation Engineering Group Co Ltd,Shanghai 200082,China;College of Construction Engineering,Jilin University,Changchun,Jilin 130026,China)
出处
《采矿与安全工程学报》
北大核心
2025年第4期915-924,共10页
Journal of Mining & Safety Engineering
基金
国家自然科学基金青年基金项目(42302273)
江苏省自然科学基金青年基金项目(BK20231080)
中国博士后科学基金面上项目(2022M713367)
江苏省双创博士计划项目(JSSCBS20221529)
中央高校基本科研基金项目(2022QN1025)
国家重点研发计划项目(2016YFC0600904)。
关键词
高压冻结冰
卸围压
力学特性
人工地层冻结
极地冰盖钻探
high-pressure frozen ice
confining pressure unloading
mechanical properties
artificial ground freezing
polar ice sheet drilling
