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“5.12”汶川大地震和“4.20”芦山地震均触发了大量的崩塌、滑坡。实震资料显示,不同地震烈度区地震触发崩塌滑坡规模的整体分布规律会发生变化。这一统计层面的认知亟待得到物理试验的验证。在自组织临界状态理论的概念框架下,开展了振动台砂堆模型试验。试验表明:输入地震波峰值加速度(PGA)为0.075g~0.125g时,落砂量与发生频率的关系可用幂律描述;PGA增加到0.15g~0.25g时,该关系服从对数正态分布;PGA增加到0.35g~0.45g时,该关系具有正态分布特征。元胞自动机模拟试验结果表明,随扰动强度增加,砂堆模型的动力学特性也经历了幂律—幂律弱化—正态分布的演变过程。按照物理学中的普适性原理,汶川、芦山地震Ⅸ度区崩塌滑坡规模与出现频率之间所呈现负幂律分布的现象,以及汶川地震Ⅺ度区所呈现的对数正态分布,可能是具有普适性意义的规律。这些认识可望为不同烈度区地震触发崩塌滑坡灾势预测提供科学依据。
5.12 Wenchuan Earthquake and 4.20 Lushan Earthquake all triggered a large number of landslides and landslides. Real seismic data show that the overall distribution of landslides triggered by earthquakes in different seismic intensity areas will change. This statistical level of awareness needs to be verified by physical tests. Under the conceptual framework of self-organized criticality theory, a sand table model test of shaking table is carried out. Experiments show that when the peak seismic acceleration (PGA) is 0.075g ~ 0.125g, the relationship between the amount of falling sand and the occurrence frequency can be described by power law. When the PGA is increased from 0.15g ~ 0.25g, the relationship obeys lognormal distribution. PGA increased to 0.35g ~ 0.45g, the relationship has a normal distribution. The results of the cellular automata simulation show that with the increase of the disturbance intensity, the dynamic characteristics of the sand pile model also undergo the evolution of power law - power law weakening - normal distribution. According to the universality principle in physics, the phenomenon of negative power law distribution between collapse landslide scale and frequency of occurrence in Ⅸ degree area of Wenchuan and Lushan earthquakes, and the logarithm normal distribution presented in Ⅺ degree area of Wenchuan earthquake may be Is a universal significance of the law. These understandings are expected to provide a scientific basis for predicting the landslide disaster in different areas of intensity.