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岩体阻尼是岩体的重要动力学参数。块体激振试验法是目前现场岩体阻尼测试最主要的方法,但这种测试方法耗费较大。通过爆破激振来测求岩体的阻尼比是一种相对简便、高效的方法,该方法需要扣除因能量的几何扩散而产生的几何阻尼的影响。为此按黏弹性阻尼模型推导出通过面波衰减计算岩体阻尼比的公式,并在海阳核电厂分别采用单孔和多孔爆破激振进行岩体阻尼试验,对得到的试验数据采用小波包进行分析。为检验该测试方法的测试效果,在同一场地按照规范进行激振试验测试,测试结果表明:通过爆破激振法测得的岩体阻尼比略大于通过块体激振法测得的岩体阻尼比,爆破激振法测得的岩体阻尼比随着爆源距的增加而减小,爆破激振的振动频率对测得的岩体阻尼比有一定影响。测试的对比结果表明利用爆破激振产生的岩体振动信号中的信息来计算岩体阻尼比具有一定的可行性。
Rock mass damping is an important dynamic parameter of rock mass. Block body vibration test method is the most important method of on-site rock mass damping test, but this test method is more expensive. It is a relatively simple and efficient method to determine the damping ratio of rock mass by blasting excitation. This method needs to deduct the influence of geometric damping caused by geometric diffusion of energy. Based on the viscoelastic damping model, a formula for calculating the damping ratio of rock mass by surface wave attenuation is deduced. The rock mass damping test is carried out in Haiyang NPP by using single-hole and multi-hole blasting excitation. The experimental data obtained are wavelet packet Analyze. In order to test the test results of the test method, the vibration test was carried out according to the specifications at the same site. The test results show that the damping ratio of the rock mass measured by blasting vibration method is slightly larger than that of the rock mass damping measured by the bulk exciter method The damping ratio of rock mass measured by blasting vibration method decreases with the increase of explosive source distance. The vibration frequency of blasting vibration has some influence on the measured damping ratio of rock mass. The test results show that it is feasible to calculate the rock mass damping ratio by using the information of rock mass vibration signals generated by blasting vibration.