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基于SHPB装置,设计了岩石动静组合加载试验系统。根据SHPB装置的理论基础,即弹性杆中一维应力波传递及试件应力均匀化,系统阐述了基于SHPB装置岩石在动静组合加载下的适用性,并针对高放废物地质处置新疆预选区天湖地段的钻孔花岗岩岩芯,开展了一系列的动静组合加载试验。动静组合拉伸加载下,随着轴向静压的增大,岩石的抗冲击强度呈现出先增大的趋势。大约在静载抗拉强度的50%时,抗冲击拉伸强度达到最大值。并且,随着轴向静压的增大,岩石的动静组合拉伸强度亦随之快速增大,最大可达到静载强度的3倍,抗冲击动载的1.5倍。试验结果表明,在冲击破坏情况下,岩石组合加载破坏模式呈现拉伸破坏,与静态拉伸破坏及一般冲击下的劈裂破坏特征基本一致。通过系列的动静组合拉伸加载,能够得到不同轴向静压及不同冲击动载下,岩石承受的临界动载荷值,进而可以确定一个施加动载荷大小的安全范围,这对于深部地下工程的爆破开挖,具有一定的理论指导意义。
Based on the SHPB device, the rock static and dynamic loading test system is designed. According to the theoretical basis of the SHPB device, namely the one-dimensional stress wave propagation in the elastic rod and the homogenization of the specimen stress, the applicability of the SHPB device based on the combination of static and dynamic loading is systematically described. In addition, Borehole granite core lake, carried out a series of static and dynamic combination of loading test. Static and dynamic combination of tensile loading, with the increase of axial static pressure, the impact strength of rock presents a first increase trend. At about 50% of the static load tensile strength, the impact tensile strength reaches a maximum value. Moreover, with the increase of axial static pressure, the dynamic tensile strength of the rock also increases rapidly, up to 3 times the static load strength and 1.5 times the impact load. The experimental results show that under the condition of impact damage, the failure mode of rock loading shows tensile failure, which is basically consistent with the static tensile failure and the splitting failure under general impact. Through a series of dynamic and static tensile loads, the critical dynamic load values of rocks subjected to different axial static pressures and different impact dynamic loads can be obtained, so that a safe range of dynamic load application can be determined, which is of great value for deep underground engineering blasting Excavation has a certain theoretical significance.