充填体与围岩组合模型剪切破裂红外辐射特征研究

Research of Infrared Radiation Characteristics of the Combined Model of Backfill Body and Surrounding Rock During Shear Rupturing

根据充填矿山实际,设计了充填体与围岩的组合模型。以德国Image IR8325红外成像系统和美国VIC-3D非接触全场应变测量系统为监测手段,对不同条件下的模型进行了剪切破裂试验,并对剪切破裂过程中模型的变形特征和红外辐射变化特征进行了研究。结果表明:在一定范围内,随着灰砂比的减小,充填体AIRT变化幅度越来越小。随着法向应力的增加,所选区域AIRT增加幅度越来越小,剪切过程中更不容易形成剪胀效应而造成AIRT多次的下降。围岩AIRT与充填体AIRT曲线的在临近应力峰值之前的小幅下降,以及模型的红外热像图中温度异常点的出现都可以作为判别组合模型破裂的前兆;法向应力的影响大于灰砂比的影响。在一定范围内,随着灰砂比的增加,剪切力的最大值呈逐渐增大的趋势。法向应力越大,剪切破裂峰值应力越大,V场位移也越大,破坏后的残余强度则越高。模型的破坏模式多呈现雁形剪切破裂,孔洞两侧围岩是应力最薄弱区域。

According to the actual condition of the filling mine, the combined model of backfill body and surrounding rock was designed. Selecting the infrared imaging system ImageIR8325 produced by German and VIC - 3D non - contact full field strain measurement system produced by America as observation method, the shear failure experiment was carried out under different conditions on the model, the deformation characteristics and infrared radiation characteristics of the model were studied during the process of rock burst. The results showed that within a certain range, with the decreasing of cement sand ratio of backfill body, the changing range of AIRT of backfill body was smaller and smaller. With the increasing of normal stress, the increasing extent of AIRT of selected areas was smaller and smaller. The shear process was not easy to formed the effect of the shear expansion, resulted in AIRT＇ s multiple declined. The slight decrease of the AIRT curves of surrounding rock and the filling body were in the proximity of the stress peak value and the appearance of temperature abnormal points in the infrared thermal image of the model could be used as the precursor of the rupture of the combined model; Influence of normal stress was greater than the influence of cement sand ratio. Within a certain range, with the increasing of cement sand ratio, the maximum value increased with the shear stress. The larger the normal stress, the greater the peak stress of the shear rupture, the greater the field displacement, the higher the residual strength after failure. The Failure of the combined model was mostly presented goose fracture mode. The surrounding rock of the hole was the weakest area of stress.