砂质泥岩在低温环境中的物理力学特性和损伤破坏对于西部富水深部竖井工程建设有重要的研究意义。依托内蒙古鄂尔多斯梅林庙矿区工程,选取深约690m的砂质泥岩为母材,研究3种温度(26℃,-10℃,-20℃)下砂质泥岩在巴西劈裂试验中的力学特性,并运用声发射仪,选取声发射能量、幅度以及峰值频率参数,分析其在不同温度试验中的变化规律。结果表明,温度对于砂质泥岩的劣化影响明显,-20℃时砂质泥岩的劈裂强度较常温及-10℃时分别减少了37.47%和29.2%。常温下砂质泥岩加载初期存在裂隙压密过程。声发射3个参数在试验过程中的变化相互验证,可以描述岩石破坏的全过程。基于累计声发射能量的损伤演化较好反映了岩石内部裂隙产生-扩展-汇集-贯通-破坏的过程,为人工冻结工程中损伤程度的评估以及预防冻结过程中渗水淹井问题提供了新的思路。
The physical-mechanical properties and the damage mechanism of frozen sandy mudstone in the low temperature are significant to the deep shaft construction in water-rich western China. Based on Meilin Temple mining projects in Ordos of Inner Mongolia, sandy mudstone in depth of more than 690 meters is selected to study Brazilian splitting tests under three different temperatures. Furthermore, acoustic emission apparatus is utilized to monitor the changes of AE energy, acoustic emission(AE) amplitude and peak frequency during the tests with the increase of load. The results show that temperature is critical to the degradation effect of sandy mudstone, and the splitting tensile strength of -20℃ sandy mudstone reduces by 37.47% and 29.2%, compared with samples at room temperature and -10 ℃, respectively. The phenomenon of crack compaction is found in early loading period at room temperature, and the changes of three different kinds of AE parameters verifies each other during the tests and the whole damage process of sandy mudstone can be described. The damage evolution based on cumulative AE energy reflects the process of internal fracture generation-propagation-transfixion -failure, which is used to evaluate the damage degree of frozen sandy mudstone and to afford a new thought for the real problems of seepage and mine flooding in actual artificial freezing engineering.