球面波传播特性和围岩动态裂纹产生的数值试验研究

利用非线性动力有限元分析程序,对于半无限岩土介质中的洞室,研究了球面波在围岩中的传播特性和动态裂纹的产生过程,比较了球面波在毛洞和锚杆加固洞室围岩中的衰减规律和动态裂纹形态的差别。结果表明:围岩动态裂纹是自由面产生的反射拉伸波及其相互叠加以及加固区与未加固区相互错动剪切的综合作用造成的;球面波强度在毛洞围岩中的衰减速度比在加固洞室中的快;锚杆加固洞室的破坏程度比毛洞轻一些;将模拟所得加固洞室围岩破坏形态与相应模型试验的结果进行了比较,发现洞室破坏形态及规律较为一致,说明了数值分析结果是可信的。研究结果对球面波的认识和防护工程的加固设计具有较好的参考价值。

Numerical test study on spherical explosive wave propagating characteristics and dynamical crack production in wall rock

By the nonlinear dynamic finite element program, spherical explosive waves propagating characteristics and process of dynamical cracks production are studied for semi-infinite rock and soil medium which contains an underground cavern. The differences of spherical explosive waves’ attenuation law and forms of dynamical cracks of unreinforced and reinforced zones by rock bolts underground cavern are compared respectively. The results indicate that the dynamical cracks of wall rocks are caused by synthetical actions which contain the tensile waves and their superposition reflected by free plane and the unreinforced and reinforced zones’ shear. The attenuation speed of spherical explosive waves of unreinforced underground cavern is faster than that of reinforced underground cavern. The reinforced underground cavern’s failure degree is lighter than that of unreinforced underground cavern. The forms of the dynamical cracks of numerical simulation are compared with the corresponding results of the model test. Some parts of the model tests data are compared with the results of numerical analysis.The forms and laws of the dynamical cracks of underground caverns are consistent between numerical analysis and model test. This shows the results of numerical simulation are credible. This numerical test results have good reference values for understanding of the spherical explosive waves and the reinforced design of protective engineering.