摘要
滑坡碎屑流的冲击是一个持续的,由大量粗细不均匀的碎屑岩粒及粗大块石共同作用的复杂力学冲击过程,冲击压力的大小和分布范围呈现一定的规律变化。以室内物理模型试验的数据为依据,运用三维离散元素法,提出滑体等效冲击力和等效冲击作用位置,探讨不同级配条件下,滑坡碎屑流冲击力的分布特征。结果表明,滑体冲击挡墙的过程可划分为动态冲击阶段和准静态堆积阶段。动态冲击过程中,滑体细颗粒组分摩擦耗能显著,导致滑体冲击力及其作用高度减小;粒径为20mm及以上粗颗粒间的碰撞作用促进了滑体内部的能量传递,导致滑体冲击力及作用高度增加,峰值冲击力呈分散性分布,峰值冲击力沿竖直高度方向的集中趋势不显著。准静态堆积阶段,挡墙所受接触力主要为后续滑体颗粒冲击能量的碰撞传递及重力分量的累积。滑坡碎屑流滑动带两侧场地条件基本相同的情况下,滑体等效冲击力的水平分布位置主要集中于迎流面中轴线附近,受颗粒级配条件影响较小。
The impact of landslide debris flow is a continuous and complicated mechanical process caused by a large number of debris particles with uneven size gravels and coarse boulders.In the process of movement and impact,the sliding bodies with different particle sizes and compositions occur internal collision,friction,jumping and so on,resulting in a certain regular change in the magnitude and distribution of impact force of landslide debris flow.Therefore,this research has important scientific significance to make up for the deficiencies in the research of landslide debris flow impact structure and to improve the design of impact-resistant structures.Based on the data of indoor physical model tests,the equivalent impact forces and the equivalent impact positions of landslide debris flow were proposed in terms of a three-dimensional discrete element method,and then it discussed the distribution characteristics of impact forces of landslide debris flow under different grading conditions.The results showed that the processes of sliding impacts on retaining wall could be divided into dynamic impact stage and quasi-static accumulation stage.During the dynamic impact process,the friction energy consumption of the fine particle components of a sliding body was significant,resulting in the reduction of impact forces and their acting height.The collisions between coarse particles with a particle size of 20 mm or more promoted the energy transfer inside the sliding body,resulting in the increase of impact force and acting height of a sliding body.The peak impact force was distributed dispersedly,and the concentration trend of the peak impact force along the vertical height direction was not significant.In the quasi-static stacking stage,the contact forces on the retaining wall were mainly the collision transfer of the impact energy of the subsequent sliding particles and the accumulation of gravity components.Under the condition that the topographical conditions on both sides of sliding zones were basically the same,the horizo
作者
李天话
樊晓一
姜元俊
LI Tianhua;FAN Xiaoyi;JIANG Yuanjun(School of Civil Engineering and Architecture,Southwest University of Science and Technology,Mianyang 621010,China;Shock and Vibration of Engineering Materials and Structures Key Laboratory of Sichuan Province,Mianyang 621000,China;Institute of Mountain Hazards and Environment,Chinese Academy of Sciences,Chengdu 610041,China)
出处
《山地学报》
CSCD
北大核心
2018年第5期740-749,共10页
Mountain Research
基金
国家自然科学基金项目(41877524)
中国科学院"率先行动"百人计划资助
西南科技大学研究生创新基金资助(18ycx088)~~
关键词
滑坡碎屑流
离散元素法
颗粒级配
冲击力分布
landslide debris flow
discrete element method
particle gradation
distribution of impact force
