摘要
火烧迹地火后泥石流灾害频发,不同地层岩性区火烧迹地发生的火后泥石流在形成条件、起动模式、成灾演变过程等方面存在着显著差异,国内不同岩性区火后泥石流发育特征研究还较为缺乏。通过对2014—2021年横断山脉东缘的四川省甘孜州和凉山州发生的12次森林火灾火烧迹地进行火后不同阶段野外跟踪调查、现场试验,查明不同岩性区火烧迹地地质环境条件、土壤性质差异、泥石流物源类型、物源补给方式及冲淤特征,揭示不同岩性区火后泥石流成灾特点的差异性。结果表明:火后变质岩区具有土壤性质变化最大,灰烬泥沙层厚3~7 cm,火后泥石流具有发生频繁、规模大等特点。变质岩区首个雨季泥石流冲出总规模是沉积岩区的4~8倍,是火成岩区的4~6倍。沉积岩与火成岩区,火灾后土壤性质改变程度较低,灰烬泥沙层仅1~3 cm厚,火后泥石流规模相对较小。研究成果深化了火后泥石流成灾机理,可有效指导不同岩性区火后泥石流防治工程设计。
The frequency of post-fire debris flow events in burned areas has increased significantly following wildfires.In different bedrock class regions,post-fire debris flow has significant differences in the formation conditions,initiation modes,and evolution characteristics.There is currently a research gap regarding the development characteristics of post-wildfire debris flows in various rock types within the domestic context.This study follows the 12 forest fires in different lithological zones in the Sichuan province of China,located on the eastern edge of the Hengduan Mountains,from 2014 to 2021,through a tracking investigation and field test at different stages in burned areas.The geological and environmental conditions of the burned area,the discrepancy in soil properties,the material sources of debris flow,the material erosion of debris flow initiation processes,and characteristics of scouring siltation of post-fire debris flow were identified.Then the variability of post-fire debris flow evolution characteristics in different lithological zones was revealed.The results indicate that the burned areas in the metamorphic rock area are characterized by the greatest changes in soil properties,thicker ash sediment layer(3-7 cm),and the highest frequency and largest scale of post-fire debris flow.The total volume of the first rainy season post-fire debris flow in metamorphic areas is four to eight times larger than in sedimentary rocks and four to six times larger than in igneous areas.In contrast,sedimentary and igneous rock areas show less pronounced changes in soil properties,thinner ash layers(1-3 cm),and comparatively smaller debris flow events.These findings advance the understanding of post-fire debris flow and provide effectively guidance for the design of post-fire debris flow prevention and control projects in different bedrock class regions.
作者
周永豪
胡卸文
曹希超
何坤
周瑞宸
龚学强
胡亚运
ZHOU Yonghao;HU Xiewen;CAO Xichao;HE Kun;ZHOU Ruichen;GONG Xueqiang;HU Yayun(Faculty of Geosciences and Engineering,Southwest Jiaotong University,Chengdu,Sichuan 611756,China;State-Province Joint Engineering Laboratory of Spatial Information Technology for High-Speed Railway Safety,Chengdu,Sichuan 610031,China;Zhejiang Engineering Survey and Design Institute Group Co.Ltd.,Ningbo,Zhejiang 315012,China)
出处
《水文地质工程地质》
北大核心
2025年第5期172-183,共12页
Hydrogeology & Engineering Geology
基金
国家自然科学基金项目(42377170)
西南交通大学博士研究生创新基金项目(CX2025YB25)。
关键词
火后泥石流
地层岩性
孕灾环境
成灾特点
物源
post-fire debris flows
bedrock class
environment of disaster
characteristics of disasters
source material
