拦挡桩群对滑坡碎屑流挡流效果的离散元模拟  

Discrete element simulation of retaining effect of retaining piles on debris flow of landslide

作　　者：陈古华 韩培锋[1,2,3] 王月明 田述军[1] 邱洪志[4,5] CHEN Guhua;HAN Peifeng;WANG Yueming;TIAN Shujun;QIU Hongzhi(Southwest University of Science and Technology,Mianyang 621010,China;Guangxi Key Laboratory of Geotechnical Mechanics and Engineering,Guilin 541004,China;Engineering Technology Research Center for Prevention and Control of Mountain Torrents,Ministry of Water Resources,Wuhan 430010,China;School of Architecture and Civil Engineering,Chengdu University,Chengdu 610106,China;Key Laboratory of Mountain Hazards and Surface Processes,Chengdu Institute of Mountain Hazards and Environment,Ministry of Water Resources,Chinese Academy of Sciences,Chengdu 610041,China)

机构地区：[1]西南科技大学土木工程与建筑学院,四川绵阳621010 [2]广西岩土力学与工程重点实验室,广西桂林541004 [3]水利部山洪地质灾害防治工程技术研究中心,湖北武汉430010 [4]成都大学建筑与土木工程学院,四川成都610106 [5]中国科学院水利部成都山地灾害与环境研究所山地灾害与地表过程重点实验室,四川成都610041

出　　处：《铁道科学与工程学报》2022年第1期129-140,共12页Journal of Railway Science and Engineering

基　　金：国家自然科学基金资助项目(41971214);广西岩土力学与工程重点实验室开放研究基金资助项目(20-Y-KF-03);水利部山洪地质灾害防治工程技术研究中心开放基金资助(CKWV2019759/KY);四川省科技计划项目(2019YJ0667);西南科技大学研究生创新基金资助项目(20ycx0043)。

摘　　要：碎屑流灾害在西南山区较普遍,且碎屑流级配变化较大,对范围内的建筑构筑物和人民生命财产安全造成不容忽视的恶劣影响。其工程防治措施是近年来的研究热点问题,而采用桩群进行拦挡的形式更是新颖,因而弄清碎屑流颗粒级配对拦挡桩群的冲击响应特征将为其治理工程结构优化与防护提供参考。基于此,采用离散元软件Discrete Element Method(DEM)定量分析碎屑流颗粒级配、桩群拦挡距离双因子对碎屑流冲击桩群过程中的速度、堆积范围和轮廓形状、堆积区域质量分布及桩群所受冲击力的影响,进一步探究不同拦挡距离下桩群的挡流效果和冲击效应特征,并从能量角度阐述其冲击响应特征机理。模拟结果表明:1)碎屑流达到其平均速度峰值的时间与小粒径颗粒含量成反比;且冲击过程中出现明显的颗粒反序现象。2)碎屑流平均速度峰值、静止堆积体质量极值分布区域与坡脚的距离同大粒径颗粒含量成正比;碎屑流在堆积区域堆积面积与拦挡距离成正比,在滑槽中堆积面积与大粒径颗粒含量成反比。3)大粒径颗粒"跳动"现象明显且对桩群的瞬时冲击作用显著,因此针对大粒径颗粒含量较大的级配体建议采用适当增大拦挡距离的方式进行拦挡。4)桩群的拦挡效应是导致碎屑流动能变化的主要原因,而碎屑流颗粒之间的摩擦、碰撞是碎屑流最终静止堆积的重要影响因素。Debris flow disasters are common in mountainous areas,and the gradation of detritus flow varies greatly,which has a serious impact on the safety of buildings and people’s lives and properties within the range.Its engineering prevention and control measures have been a hot research topic in recent years,and the form of using piles for blocking is even more novel.Therefore,clarifying the impact response characteristics of the debris flow particle gradation pair blocking piles will provide structural optimization and protection for its treatment engineering.Based on the condition,the discrete element software Discrete Element Method(DEM)was used to quantitatively analyze the impact of the debris flow particle gradation and pile blocking distance on the velocity,accumulation range and contour shape,and the quality of the accumulation area during the impact of the debris flow on the pile group.The distribution and the impact of the pile group were affected by the impact force.The flow blocking effect and impact effect characteristics of the pile group under different blocking distances were further explored,and the impact response characteristic mechanism was explained from the energy point of view.The results are as follows.(1)The time for the debris flow to reach the peak of its average velocity is inversely proportional to the content of small particles.And there is an obvious reverse order of particles during the impact process.(2)The average velocity peak of the debris flow and the distance between the mass extreme value distribution area of the static accumulation body and the toe of the slope are proportional to the content of largesize particles.The accumulation area of the debris flow in the accumulation area is proportional to the blocking distance.The accumulation area is inversely proportional to the content of large particles.(3)The“jumping”phenomenon of large-size particles is obvious and the instantaneous impact on the pile group is significant.Therefore,it is recommended to appropriately increase

关 键 词：滑坡碎屑流 颗粒级配 拦挡距离 桩群 挡流效果 DEM 

分 类 号：P694[天文地球—地质学]