巷道岩爆红外辐射前兆特征实验研究

Infrared radiation portentous characteristics of rock burst in roadway

以美国Therma CAM SC3000红外热像仪为观测手段,选取含孔花岗岩进行不同水平应力下巷道岩爆模拟实验,并结合数值模拟,对岩爆过程中应力分布和红外辐射温度变化特征进行了实验研究。结果表明:1)轴向应力与水平应力比值随着水平应力的增大而减小,水平应力越高,岩爆发生的最大主应力值也相应提高。2)岩爆发生的红外前兆时空演化特征:主破裂前,孔洞左右两侧平均红外辐射温度表现为突然升温型或略降转升型,对应的破裂机制分别为压剪破裂和先张拉后压剪的复合破裂形式;主破裂沿孔洞左右两侧高温异常条带扩展。3)岩爆过程中,孔洞上、下区域增温幅度比左右两侧低,增温较为稳定,孔洞上边区域AIRT均比孔洞下边区域高。4)水平应力越大,孔洞周围平均红外辐射温度越高。

Selecting the infrared thermal imager CAM SC3000 produced by America as observation method, an experiment was carried out to simulate roadway rock burst under different horizontal stress by using the granites with hole. Combined with numerical simulation, the stress distribution and infrared radiation temperature characteristics were studied during the process of rock burst. The results show that the ratio of axial stress and horizontal stress decreases with the increase of horizontal stress, and the greater the horizontal stress is, the higher the maximum principal stress of rock burst is. The average infrared thermal temperature（AIRT） in the left and right sides of the hole suddenly increase or slightly decrease and then transfer to increase, and the corresponding fracture mechanism is the compressively-sheared fracture form and the composite form with early tensile fracture and late compressively-sheared fracture. The main fracture zone extends along the high temperature abnormal stripe on the left and right sides of the hole. During the rock burst process, the increasing extent of temperature above and below the hole is lower than that in the left and right sides of the hole, that is, the temperature increasing extent above and below the hole is relatively stable. Meanwhile, the AIRT above the hole is higher than that below the hole. Moreover, the greater the horizontal stress is, the higher the average infrared radiation temperature around the hole is.