| 火烧迹地土壤团聚体稳定性原位快速测定方法 |
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| 引用本文： | 周永豪, 胡卸文, 金涛, 段雯超, 龚学强, 席传杰, 曹希超. 火烧迹地土壤团聚体稳定性原位快速测定方法[J]. 中国地质灾害与防治学报, 2023, 34(6): 97-104. doi: 10.16031/j.cnki.issn.1003-8035.202209022 |
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| 作者姓名： | 周永豪 胡卸文 金涛 段雯超 龚学强 席传杰 曹希超 |
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| 作者单位： | 西南交通大学地球科学与环境工程学院，四川 成都 611756 |
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| 基金项目： | 国家自然科学基金项目（42377170） |
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| 摘 要： | 森林火灾后因火烧迹地土壤斥水性，导致坡面径流和土壤可蚀性增强，提高了火后泥石流易发性，而土壤团聚体稳定性是影响土壤入渗能力和侵蚀敏感性的关键指标。目前常用于火烧迹地土壤团聚体稳定性测定的水滴冲击测定方法（counting the number of water drop impacts，CND），不适用于原位测定且耗时较长（滴定一组团聚体需要数小时）。因此文章提出一种基于冲击振荡破坏效应的团聚体稳定性测定方法（shock and vibration damage method，SVD）。充分考虑容重、有机质含量和斥水性对土壤团聚体稳定性的影响，通过室内火烧模拟试验，制备了13种类型的土壤团聚体。采用自制的试验仪器进行SVD法正交试验测定土壤团聚体质量损失率，并与传统CND法测得的破坏团聚体的水滴数量进行对比。结果表明：SVD法的测定MT-6方案（冲击高度1 m、容器容水量40%、冲击5次、测定团聚体20颗）与CND法的测定结果具有很强的一致性（Kendall系数=0.797）和相关性(R2=0.634)，测定时间较短（测定一组团聚体约5 min），且测定结果区分度较好（约62%的团聚体MLR位于区分度良好的40%～60%区间），将其作为SVD法的最优测定方案。此外，SVD法试验装置结构简单、便携易拆卸，可用于原位快速且定量地区分火烧迹地不同火烈度下土壤团聚体稳定性水平，对火烧迹地土壤侵蚀、水土流失治理以及火后泥石流起动机理研究具有重要指导意义。
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| 关 键 词： | 土壤团聚体稳定性 火烧迹地 质量损失率 冲击振荡破坏 火后泥石流 |
| 收稿时间： | 2022-09-16 |
| 修稿时间： | 2022-11-29 |
An in-situ method for assessing soil aggregate stability in burned landscapes |
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| ZHOU Yonghao, HU Xiewen, JIN Tao, DUAN Wenchao, GONG Xueqiang, XI Chuanjie, CAO Xichao. An in-situ method for assessing soil aggregate stability in burned landscapes[J]. The Chinese Journal of Geological Hazard and Control, 2023, 34(6): 97-104. doi: 10.16031/j.cnki.issn.1003-8035.202209022 |
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| Authors: | ZHOU Yonghao HU Xiewen JIN Tao DUAN Wenchao GONG Xueqiang XI Chuanjie CAO Xichao |
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| Affiliation: | Faculty of Geosciences and Environment Engineering, Southwest Jiaotong University, Chengdu, Sichuan 611756, China |
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| Abstract: | Due to soil repellency in burned areas, slope runoff and soil erodibility escalates following forest fires, increasing the vulnerability to post-fire debris flows. Soil aggregate stability is a critical determinant of soil infiltration capacity and erosion susceptibility. The prevalent method of assessing soil aggregate stability in burned areas, the counting the number of water drop impacts (CND) method, is time-intensive and impractical for in-situ measurements. In response, this study introduces a novel technique based on the shock and vibration damage (SVD) effect for evaluating soil aggregate stability in burned areas. Thirteen distinct soil aggregate types were meticulously prepared for indoor simulated fire testing, with due consideration to factors such as bulk weight, organic matter content, and water repellency, which influence stability of soil aggregates. Employing a custom-built test apparatus, the mass loss rate (MLR) of soil aggregates was determined through orthogonal experiments using the SVD method and compared against the standard CND technique's quantification of water droplet-induced aggregate destruction. The findings demonstrated that SVD method, employing Test Scheme 6 (testing 20 aggregates, 1-meter impact height, 40% water content, and five impacts), exhibits excellent agreement (Kendall coefficient = 0.797) and correlation (R2 = 0.634) with CND method outcomes. This testing scheme, characterized by rapid determination and effective discrimination, is identified as the optimal testing approach. The SVD testing apparatus is straightforward, portable, and easily disassembled, rendering it suitable for on-site use. It can be used to distinguish the stability level of soil aggregates swiftly and quantitatively under various fire intensities in burned areas in situ, which is an important guiding significance for the study of soil erosion, erosion control, and post-fire debris flow initiation mechanism in burned areas. |
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| Keywords: | soil aggregates stability burned area mass loss rate shock and vibration damage post-fire debris flows |
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