梅林庙矿负温饱水红砂岩加卸载力学特性研究  

Mechanical properties of saturated red sandstone of Meilinmiao mine under loading and unloading at negative temperatures

作　　者：单仁亮[1] 杨昊[1,2] 张晋勋[2] 郭志明[1] 赵丁鸿 

机构地区：[1]中国矿业大学(北京)力学与建筑工程学院,北京100083 [2]北京城建集团有限责任公司博士后工作站,北京100088

出　　处：《采矿与安全工程学报》2016年第5期924-931,共8页Journal of Mining & Safety Engineering

基　　金：国家自然科学基金项目(41572270);国家自然科学基金委员会与神华集团有限责任公司联合资助项目(U1261126)

摘　　要：为研究冻结岩石在卸围压条件下强度特性、变形特性以及宏观破坏形态,以鄂尔多斯梅林庙矿风井冻结施工500～600 m处饱水红砂岩为研究对象,分别对其进行不同温度（10,-5,-10,-15℃）、不同围压（4,8,12 MPa）条件下的三轴压缩试验和三轴峰前、峰后卸围压试验。结果表明：1）饱水红砂岩峰前卸围压峰值强度大于单轴压缩强度,小于三轴压缩强度;峰后卸围压峰值强度近似等于三轴压缩强度,其值受人为因素和试验方案影响显著。2）峰前卸围压时,温度越低,试件变形对围压越不敏感,抗扰动性越强;初始围压越大,试件变形对围压越不敏感,抗扰动性越差;峰后卸围压时,温度对试件强度影响甚微,峰后强度大小取决于实时围压值。3）峰前卸围压破坏不同于三轴加载破坏和峰后卸围压破坏;峰前卸围压破坏实质为拉破坏,破坏形态取决于卸围压过程中裂隙的发育状态,峰后卸围压破坏形态取决于前期加载历程,与卸围压无关。This paper investigates the strength and deformation characteristics and macroscopic failure modes of saturated red sandstones at 500-600 m depths of airshaft frozen construction zone of Meilin- miao mine in Ordos. A series of triaxial compression, pre-peak and post-peak unloading tests have been performed at different temperatures （10, -5, -10 and -15 ℃） and various confining pressures （4, 8 and 12 MPa）. The results have shown that 1） The strength of sandstones in pre-peak unloading tests is greater than uniaxial compressive strength but less than triaxial compression strength; the strength in post-peak unloading tests is approximately equal to triaxial compressive strength, which is affected by artificial factors and experimental schemes significantly; 2） In pre-peak unloading tests, the lower the temperature is applied, the lower deformation sensitivity on confining pressure and the larger resistance to disturbance the rock has; while the larger initial confining pressure leads to the lower deformation sensitivity and antidisturbance; in post-peak unloading tests, the influence of temperature variation on strength is negligible, and it only depends on real-time confining pressure; 3） The failure modes in pre-peak unloading tests are different from triaxial compression and post-peak unloading tests. Tensile fail： ure governs in pre-peak unloading tests, which depends on the development of fractures within the rock at the stage of unloading. Conversely, failure modes in post-peak unloading tests are determined by loading history, which is irrelevant to unloading process.

关 键 词：卸围压试验 负温岩石 力学特性 饱水红砂岩 破坏形式 

分 类 号：TU457[建筑科学—岩土工程]