高阻尼橡胶用于岩石动载冲击防护的吸能特性试验研究

Experimental study on energy absorption of high damping rubber for rock under dynamic loads

为了有效控制和减少深部高应力岩体冒落、硐室失稳及岩爆等工程动力灾害,借助于高阻尼橡胶材料在抗冲击、抗剪及能量吸收等方面的优越性能,拟研发带有高阻尼橡胶材料的深部新型硬岩小应变吸能锚杆,其吸能效果主要取决于高阻尼橡胶材料性能,为了系统评价高阻尼橡胶用于岩石冲击防护的吸能特性,文中利用φ50 mm分离式Hopkinson冲击压缩试验系统,对高阻尼橡胶、花岗岩–花岗岩组合试件以及高阻尼橡胶–花岗岩组合试件开展不同加载速率条件下的冲击试验,探讨对比高阻尼橡胶的吸能规律及其吸能效果。研究结果表明:高阻尼橡胶吸收的能量随入射能增加呈线性增加,说明吸收的能量占入射能的比例恒定;花岗岩与花岗岩组合试件分形维数增长速度比橡胶花岗岩组合试件快5.5倍,反映高阻尼橡胶在外荷载激振下具有良好的吸能特性;不同厚度的高阻尼橡胶材料存在最佳吸收能量,入射能在200~250 J范围内橡胶最佳厚度为15~20 mm,研究成果将为吸能锚杆的研发提供理论和数据支撑。

In order to control and reduce rockfall,chamber instability,rockburst and other engineering dynamic,a new energy absorbing bolt is developed,taking advantage of the excellent properties of high damping rubber such as resisting impact effect,resisting shearing and absorbing energy. In this paper,to evaluate the energy absorbing characteristics of high damping rubber on impact protection of rock,a series of impact tests were conducted by SHPB system of φ50 mm. The energy absorbing characteristics of rubber samples,granite samples and rubber-granite samples under different loading rates were obtained. Results shows that the energy absorbed by high damping rubber increases linearly with incident energy,which indicates that the energy absorbing rate is nearly constant. For granite samples,the growth rate of fractal dimension is 5.5 times that of rubber-granite samples,which reflects good energy absorbing characteristics of high damping rubber under dynamic loading. In addition,the optimal relationship between rubber thickness and absorbed energy is confirmed. When the incident energy is between 200–250 J,the recommended rubber thickness of rubber is 15–20 mm. The research results can provide design guidance and theoretical foundation for the development of energy absorbing bolts.