爆炸荷载作用下模型介质裂纹扩展试验与分析

为研究爆炸载荷作用下裂隙介质裂纹扩展规律,以含人工裂隙的有机玻璃薄板为介质,分别以炮孔中心到人工裂隙垂直距离L和人工裂隙长度D为变量,采用单发雷管爆炸加载试验模型进行试验。试验结果表明,爆炸荷载作用将使裂隙介质形成径向裂纹、翼裂纹、层裂裂纹和似层裂裂纹;人工裂隙能够阻隔径向裂纹的扩展,径向裂纹的扩展对距离L比长度D更敏感;翼裂纹是爆炸绕射波或绕射波与压缩应力波共同作用产生的,翼裂纹的长度随距离L增加而降低;入射压缩应力波与反射拉伸应力波叠加形成的净拉伸应力拉裂介质形成层裂效应、引起径向裂纹弯曲形成似层裂效应,层裂裂纹和似层裂裂纹几乎平行于人工裂隙。研究结果可为裂隙岩体爆破设计、冲击矿压防治和结构工程防护等提供理论依据。

Experiment and Analysis of Crack Propagation of Model Medium Subjected to Blasting Load

In order to study the crack propagation in pre-fractured medium subjected to blasting load,taking organic glass sheet with prefabricated artificial fracture as test medium,taking the vertical distance from blast hole center to artificial fracture L and the artificial fracture length D as variables,using single detonator,blasting load experiment was carried out.Experimental results show that radial cracks,wing cracks,spalling cracks and quasi-spalling cracks are formed due to blasting load;radial crack propagation is blocked by the artificial fracture and is more sensitive to the distance L than the length D;wing cracks are produced by blasting diffracted wave or combined action of diffracted wave and compression stress wave;wing cracks become shorter with the distance L increasing;pure tensile stress which is formed through superposition of incident compression wave and reflected tensile stress wave forms spalling effect by tension fracture in pre-fractured medium and causes radical cracks to be curved to form quasi-spalling effect;spalling cracks and quasi-spalling cracks almost parallel to artificial fracture.Above results provide a theoretical basis for fractured rock mass blasting design,rock burst prevention and structural engineering protection,etc.