Dynamic impact properties of deep sandstone under thermal-hydraulicmechanical coupling loads  

作　　者：CAO Chunhui DING Haonan ZOU Baoping 

机构地区：[1]School of Civil Engineering and Architecture,Zhejiang University of Science and Technology,Hangzhou 310023,China [2]Zhejiang-Singapore Joint Laboratory for Urban Renewal and Future City,Hangzhou 310023,China

出　　处：《Journal of Mountain Science》2024年第6期2113-2129,共17页山地科学学报（英文）

基　　金：supported by the Science and Technology Commissioner Project of Zhejiang Province(2023ST04);the supporting funds for scientific research launch of Zhejiang University of Science and Technology(F701104M11).

摘　　要：The deep rock mass within coal mines situated in a challenging environment are characterized by high ground stress,high geotemperature,high osmotic water pressure,and dynamic disturbances from mechanical excavation.To investigate the impact of this complex mechanical environment on the dynamic characteristics of roof sandstone in self-formed roadways without coal pillars,standard specimens of deep sandstone from the 2611 upper tunnel working face of the Yongmei Company within the Henan Coal Chemical Industry Group in Henan,China were prepared,and an orthogonal test was designed.Using a self-developed geotechnical dynamic impact mechanics test system,triaxial dynamic impact tests under thermal-hydraulicmechanical coupling conditions were conducted on deep sandstone.The results indicate that under high confining pressure,deep sandstone exhibits pronounced brittle failure at low temperatures,with peak strength gradually decreasing as temperature and osmotic water pressure increase.Conversely,under low confining pressure and low temperature,the brittleness of deep sandstone weakens gradually,while ductility increases.Moreover,sandstone demonstrates higher peak strength at low temperatures under high axial pressure conditions,lower peak strength at high temperatures,and greater strain under low axial pressure and high osmotic water pressure.Increases in impact air pressure and osmotic water pressure have proportionally greater effects on peak stress and peak strain.Approximately 50%of the input strain energy is utilized as effective energy driving the sandstone fracture process.Polar analysis identifies the optimal combination of factors affecting the peak stress and peak strain of sandstone.Under the coupling effect,intergranular and transgranular fractures occur within the sandstone.SEM images illustrate that the damage forms range from minor damage with multiple fissures to extensive fractures and severe fragmentation.This study elucidates the varied dynamic impact mechanical properties of deep sandstones under the

关 键 词：Deep sandstone Thermal-hydraulicmechanical coupling Dynamic impact STRESS-STRAIN Failure Modes Polar analysis 

分 类 号：TD313[矿业工程—矿井建设]