首页|黄土堆填场地转化为泥石流物质过程——以兰州市碱水沟为例

黄土堆填场地转化为泥石流物质过程——以兰州市碱水沟为例

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黄土地区人工堆填场地是近几年兰州市拓展城市用地空间的一个新举措,在场地边缘形成较多堆填边坡,成为参与泥石流的潜在物质.以兰州市碱水沟"4·19"泥石流灾害为例,结合粒径分析试验、扫描电镜图像及野外入渗试验,探讨其特征及运行模式,并提出相应的治理建议.结果表明:1)黄土地区人工堆填体颗粒粒径＜1.000 mm的物质约占11.4％～55.2％,有利于泥石流启动;2)以2个相距170 m的泥位调查断面做比较,下游断面流量增加2.5倍,说明入渗引起的黄土湿陷能促进泥石流物质的转化率;3)入渗试验表明:黄土堆填场地渗透性强,低水头条件下8 min左右达到稳定入渗状态,高水头条件下12 min左右达到稳定入渗状态,能在较短的时间内使土壤软化,影响人工堆填场边坡稳定,提高泥石流物质转化速度;4)黄土地区人工堆积体场地诱发的泥石流流动模式复杂、多变,兼具波状流和间歇流的特点.在此基础上,笔者提出过程管理和重点防护相结合的防治模式.
Debris flow disaster induced by artificial accumulation site in loess area:An instance of Jianshui valley,Lanzhou city
[Background]The artificial accumulation site in the loess area is a new measure for Lanzhou city to expand the urban land space in recent years.It is inevitable to form more artificial landfill slopes at the edge of the site,which may become a potential material to be involved in debris flow.[Methods]This paper took the"4·19"debris flow disaster in Jianshui valley of Lanzhou city as an example.Combined with grain size analysis experiment,SEM image and field infiltration experiment,this paper discussed its characteristics and operation mode,and proposed corresponding treatment suggestions.[Results]1)Materials with grain size＜1 mm in the loess area accounted for 11.4％-55.2％,which was conducive to the initiation of debris flow.2)Compared with two mud level survey sections with a distance of 170 m,the flow of the downstream section increased by 2.5 times,indicating that the loess subsidence caused by infiltration promoted the conversion rate of debris flow material.3)The infiltration experiment showed that loess accumulation site had strong permeability.It basically reached a stable infiltration state in about 8 min under low water head conditions,and basically reached a stable infiltration state in about 12 min under high water head conditions.It caused soil softening in a short time,affecting the slope stability of artificial landfill site,and thus improved the material conversion rate of debris flow.4)The flow pattern of debris flow induced by artificial accumulation site in the loess area is complex and changeable,which has the characteristics of wavy flow and intermittent flow.[Conclusions]On this basis,authors propose a prevention model that combines process management and key protection.

artificial accumulation siteJianshui valleyloess collapsibilitydensity of the accumulationwavy flow and intermittent flowprevention model

刘兴荣、张连科、董耀刚、宿星、王喜红

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甘肃省科学院地质自然灾害防治研究所,730000,兰州

人工堆积场地 碱水沟 黄土湿陷 密实度 波状流和间歇流 防治模式

国家自然科学基金甘肃省2021年度重点人才项目兰州市科技局年度科技计划项目甘肃科学院科技产业化项目甘肃科学院应用研究与开发项目

420670662021RCXM0662019-1-22CY082021JK-07

2024

10.16843/j.sswc.2021129

中国水土保持科学
中国水土保持学会

中国水土保持科学

CSTPCD北大核心
影响因子：0.902
ISSN：1672-3007
年,卷(期)：2024.22(2)
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