地下水库人工坝体强度损伤演化特征试验研究

Experimental study of damage evolution of artificial dam strength of underground reservoir

在我国西部生态脆弱矿区,地下水库储水技术已成为煤水资源共采技术的重要组成部分,其中人工坝体的稳定性是评价地下水库能否构建并长期安全使用的关键因素之一。为研究地下水库人工坝体在吸水-失水、采动及矿震等循环作用下强度变化规律,以大柳塔矿地下水库人工坝体所使用的C30混凝土试样为例,开展了超声-回弹综合测强、循环加载和单轴压缩声发射试验研究。研究结果表明:超声-回弹综合测强公式可以对水作用下混凝土试样强度进行预测;循环加载影响下试样强度最大下降比例约17%,而水作用下的循环加载试样强度最小下降比例达26%;并结合声发射振铃计数研究了混凝土试样受载下的损伤演化特征。由此可知,循环加载(采动及矿震)和水(吸水-失水)共同作用下,对地下水库人工坝体稳定性影响较大。

Water storage technology via underground reservoirs has become a crucial component of water coal joint mining in ecologically fragile mining area of Western China. Stability is one of the critical factors for the construction of underground reservoirs and its long term utilization. To investigate the impacts of repeating water absorption and dr ying,mining and rock burst on the change of strength,the authors took C30 concrete as an example which was used in building artificial dam of underground reservoirs in Daliuta colliery. Strength test via ultrasonic rebound comprehensive method,cyclic loading test and acoustic emission（AE）uniaxial compression test were employed in this study. The re sults showed that the formula of ultrasonic rebound comprehensive strength could predict the concrete strength under water intrusion. Also,the strength of concrete had a maximum fall by 17% affected by cyclic loading,while the figure for concrete with water intrusion showed a minimum decrease by 26%. The damage evolution characteristics of con crete specimens subjected to loading were investigated by AE counts. In summary,the authors found the co effects of cyclic loading（mining and rock burst）and water had a significant impact on the stability of artificial dam of under ground reservoirs.