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在我国西部山区,由高速远程滑坡碎屑流导致的群死群伤事件时有发生,对滑坡碎屑流的高速远程机制研究迫在眉睫。以汶川地震触发的文家沟高速远程滑坡碎屑流为研究对象,利用其堆积物中出露的冲沟对碎屑流堆积物的堆积结构进行研究,结果表明,碎屑流堆积物具有明显的反序结构;进一步利用环剪试验对碎屑流流动过程中不同深度处碎屑颗粒的长距离剪切过程进行模拟,结果显示,颗粒破碎是滑坡碎屑流堆积物反序结构形成的主要原因之一,碎屑流流动过程中由于底部颗粒所受正应力最大,因此破碎越彻底,而向上碎屑颗粒所受正应力逐渐减小,破碎程度也逐渐减小,因此形成反序结构;而底部碎屑颗粒破碎导致碎屑流剪切强度降低,进一步导致碎屑流底部与地面之间摩擦阻力降低,是滑坡碎屑流能够高速远程的主要原因之一。研究成果能够为西部山区高速远程滑坡碎屑流的致灾范围预测提供科学依据,具有一定的理论和实际意义。
In the western mountainous area of China, the mass extinction and mass anomalies caused by the high-speed remote landslide debris flow occur frequently, and the research on the high-speed remote mechanism of landslide debris flow is imminent. Wenchuan earthquake triggered Wenchuan high-speed remote landslide debris flow for the study, the use of its deposits exposed gully on the debris flow debris accumulation structure research results show that the debris flow deposits have obvious The cyclic shear test was used to simulate the long-distance shearing process of debris particles at different depths in the flow of debris flow. The results show that the particle fragmentation is the main formation of the reverse structure of landslide debris flow deposits One of the reasons is that in the process of debris flow, the normal stress of the bottom particle is the largest, so the more complete the fracture, and the upward normal stress of the detrital particles gradually decreases and the degree of fragmentation gradually decreases, thus forming reverse order structure; However, the crushing of the debris at the bottom causes the shear strength of the debris flow to decrease, further reducing the frictional resistance between the bottom of the debris flow and the ground, which is one of the main reasons for the high speed and remoteness of the debris flow in the landslide. The research results can provide a scientific basis for predicting the disaster range of high-speed remote landslide debris flow in western mountainous areas, which has a certain theoretical and practical significance.