摘要
中西部矿井常采用冻结法施工技术,冻结壁中的裂隙会影响其力学特性使施工过程中产生透水等安全隐患。为掌握冻结裂隙砂岩破坏机理,进一步分析冻结法凿井施工过程中冻结壁稳定性,以冻结砂岩为研究对象,开展7种裂隙倾角α=0°,15°,30°,45°,60°,75°,90°及3种裂隙长宽比β=10∶1,5∶1,2∶1的单轴压缩试验,分析强度及弹性模量的变化特征,并通过高速摄影机记录试样裂纹的起裂和破坏过程。结果表明:冻结砂岩强度随裂隙长宽比β的增大而增大,随裂隙倾角α的变化趋势呈抛物线型与线性2种类型。当裂隙长宽比β大于2时,其弹性模量在α=45°时取得最大值,在α=60°取得最小值。β=2时弹性模量随α增大而增大,在α=75°取得最大值。冻结裂隙砂岩的破坏模式以张拉及混合破坏模式为主,压剪破坏模式出现在α=45°及α=60°的试样中。试验结果有助于预测富水深层矿井冻结壁裂纹演化规律,为中西部地区矿井变形及稳定性提供理论参考。
The freezing construction technology is often used in mines in the Midwest,and the fissures in the frozen walls can affect their mechanical properties resulting in safety hazards such as water penetration during construction.To explore the damage mechanism of frozen fractured sandstone and further analyze the stability of frozen walls during the construction of frozen well drilling,this paper takes frozen sandstone as the research object and carries out uniaxial compression tests with seven fracture inclination angles of α=0°,15°,30°,45°,60°,75°,and 90°and three fracture aspect ratios of β=10∶1,5∶1 and 2∶1 to analyze the characteristics of strength and elastic modulus change.The process of crack initiation and damage of the specimens was recorded by a high-speed camera.The results indicate that:Frozen sandstone strength increases with increasing of fracture aspect ratioβ.The trend in strength with fracture dip angleαis parabolic and linear.When the gap aspect ratioβis greater than 2,the modulus of elasticity reaches a maximum value atα=45°and a minimum value atα=60°.The modulus of elasticity increases withαatβ=2 and reaches a maximum atα=75°.Frozen fractured sandstone damage modes are dominated by tension and mixed damage modes.Crush shear damage patterns occur in specimens withα=45°andα=60°.The test results help to predict the evolution law and mechanical characteristics of freezing wall cracks in water-rich deep-level mines and provide theoretical reference for the deformation and stability of mines in the central and western regions.
作者
赵涛
乔煜哲
冯云枫
ZHAO Tao;QIAO Yuzhe;FENG Yunfeng(College of Civil and Architectural Engineering,Xi'an University of Science and Technology,Xi'an 710054,China)
出处
《西安科技大学学报》
CAS
北大核心
2023年第2期342-351,共10页
Journal of Xi’an University of Science and Technology
基金
陕西省重点研发计划项目(2019SF-264)。
关键词
单裂隙岩体
裂纹扩展
单轴压缩
冻结砂岩
破坏模式
single fissure ock mass
crack extension
single axis compressi on
frozen sandstone
destruction mode
