| 降雨诱发深层老滑坡复活变形的动态作用机制 |
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| 引用本文： | 宋琨,陈伦怡,刘艺梁,易庆林,董志鸿.降雨诱发深层老滑坡复活变形的动态作用机制[J].地球科学,2022,47(10):3665-3676. |
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| 作者姓名： | 宋琨 陈伦怡 刘艺梁 易庆林 董志鸿 |
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| 作者单位： | 1.三峡大学防灾减灾湖北省重点实验室, 湖北宜昌 443002 |
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| 基金项目： | 国家自然科学基金项目42077239国家自然科学基金项目41702378 |
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| 摘 要： | 强降雨易引发大型深层老滑坡的复活变形，研究其作用机制对建立滑坡变形破坏的降雨阈值，实现滑坡灾害的预警预报具有重要意义.以三峡库区秭归县谭家湾大型深层老滑坡为例，在地表宏观裂缝时空分布规律的精细描述基础上，结合15年的人工监测和2年的实时监测数据，分析了老滑坡的复活变形特征和发展过程.通过滑坡阶跃阶段的位移与降雨（当前降雨和前期降雨）的相关性分析，提出了降雨对深层滑坡复活变形演化过程的动态作用机制.谭家湾滑坡的7次“阶跃”变形与强降雨相关，但累积位移增量与累积降雨量无明显正相关关系，水平位移增量基本相同时，累积降雨量明显不同.引起第一次阶跃变形的累积降雨量和最大日降雨量均明显大于后续阶段，可能受控于强降雨的作用机制由“孔隙渗流”为主，逐渐转变为“渗透性增加的孔隙渗流+裂隙优势流”的综合渗流模式.这对进一步深入研究强降雨诱发深层老滑坡阶跃变形的内在机理与灾害预警具有一定的理论意义和参考价值.
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| 关 键 词： | 深层滑坡 阶跃变形 降雨滑坡 入渗机制 相关性分析 工程地质 |
| 收稿时间： | 2022-03-03 |
Dynamic Mechanism of Rain Infiltration in Deep-Seated Landslide Reactivate Deformation |
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| Abstract: | Heavy rainfall is a main factor for reactivating the deformation of large deep-seated landslides. Understanding the infiltration mechanism is of great significance to obtaining the rainfall thresholds for landslide reactivation and hence facilitating early warning. Tanjiawan landslide is a well-studied large-scale and deep-seated reactivated landslide in Zigui County of the Three Gorges Reservoir Area. It is therefore considered as a typical example in this study, and the spatiotemporal distribution of surface cracks with time series were described and analyzed herein. 15 years of manual monitoring data and 2 years of real-time monitoring data were employed to analyze the deformation process of the landslide. By exploring the correlation between the displacement and the cumulative as well as antecedent rainfall in the stepping stage, a dynamic mechanism of infiltration was proposed for the reactivated deformation evolution in the deep-seated landslide. It is demonstrated that the 7 stages of step-like deformation were related to the heavy rainfall of the Tanjiawan landslides, but the cumulative horizontal displacement increment had no obvious positive correlation with the cumulative rainfall. Moreover, even when the increment of horizontal displacement is similar, the accumulate rainfall can still be quite different. The cumulative rainfall and maximum daily rainfall that caused the first step deformation were much greater than those in the subsequent stages, and the analysis indicated that it may be controlled by the dynamic mechanism of infiltration. Furthermore, the infiltration has transformed from pore seepage to coupled pore seepage with larger permeability and crack preferential flow. It has a theoretical significance and reference value for further study of the mechanism and early warning of deep-stead landslide reactivation induced by heavy rainfall. |
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