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工程科学与技术:2021,53(4):140-148
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基于运动波壤中流理论与无限边坡稳定分析理论的滑坡预测模型
(1.福州大学 土木工程学院,福建 福州 350108;2.台湾海洋大学 河海工程学系,台湾 基隆 20224)
Integrating Kinematic Subsurface-wave Approximation with Infinite-slope Stability Analysis for Landslide Predictions
(1.College of Civil Eng., Fuzhou Univ., Fuzhou 350108, China;2.Dept. of River and Harbor Eng., Taiwan Ocean Univ., Keelung 20224, China)
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投稿时间:2020-07-31    修订日期:2021-06-18
中文摘要: 滑坡往往发生在强降雨时期的陡峭山坡区域,建立滑坡预测模型是山坡地防灾重要策略之一。结合山坡运动波壤中流理论与无限边坡稳定分析理论,构建了降雨型浅层滑坡的预测模型。首先,根据运动波壤中流理论对坡面进行产汇流计算得到出口断面径流过程线及土壤蓄水量随时间与空间变化过程;然后,研究坡面出口处饱和水位随时间的变化特性;最后,根据无限边坡稳定分析理论计算坡面平均安全系数变化过程,对坡面稳定性进行分析。将模型应用于台湾高雄市那玛夏区达喀尔努瓦里,研究发现,在莫拉克台风期间滑坡发生的预测位置与卫星影像图所得到的结果一致,率定的土壤参数物理意义明显,说明此模型具有一定的可靠性。同时,分析了双峰降雨过程中坡面安全系数的变化规律。随着降雨量增大,壤中流流量快速增大,出口处饱和水位快速上升,坡面安全系数快速减小;当降雨量减少时,土壤排水速率大于降雨强度,饱和水位缓慢下降,安全系数缓慢增大至天然状态条件下的安全系数。在此基础上,进一步分析对称双峰降雨条件下表层土壤厚度对坡面稳定性的影响,结果显示,坡面安全系数随着土壤厚度增大而减小,在先小后大的降雨条件下土壤汇集的水量较多,发生滑坡的可能性增大。上述土壤蓄水机制的研究,可以为滑坡预测模型提供物理依据。
Abstract:Landslides often occur in steep mountain areas during heavy rainstorms. Establishing landslide prediction models is one of the essential strategies for disaster prevention in mountain areas. The kinematic subsurface-flow approximation and the infinite-slope instability analysis were used to develop a rainfall-induced shallow landslide prediction model. Firstly, the runoff hydrograph and the temporal variation of soil water storage were obtained by calculating the runoff yield and concentration of slope according to the theory of the kinematic subsurface-flow approximation. Then the temporal variation characteristics of saturated water level was studied. Finally, based on the theory of the infinite-slope instability analysis, and the analyzed slope stability the temporal variation of factor of safety was calculated. The Namasia District in Kaohsiung of Taiwan was chosen as a studied area to test the applicability of the model. It was found that the predicted location of landslide occurrence during Typhoon Morakot is consistent with those obtained from satellite images, and the values of the calibrated model parameters are consistent with physical meanings, which shows that the physically based model has good reliability. Moreover, the variation of the slope factor of safety was analyzed by applying double-peak design hyetographs with different rainfall peaks. The result showed that when the rainfall increases, the subsurface flow, and the saturated water level raise quickly to result in the decreasing of factor of safety value. On the contrary, while the rainfall decreases, the rate of subsurface outflow is higher than rainfall intensity, the saturated water level would drop slowly. Hence, the slope factor of safety is increasing and gradually returns to its natural state. Moreover, the influence of soil thickness on slope stability was further studied during the rainstorms. The results showed that factor of safety is reduced as the increasing of the soil thickness. It also reveals that if a low-peak rainfall occurs and followed by a high-peak rainfall, it would result in a higher possibility of landslides. It was expected that this study can give a clear physical explanation for the landslide occurrence and provide a useful tool for landslide prediction.
文章编号:202000637     中图分类号:TV121+.3;P641    文献标志码:
基金项目:福建省自然科学基金项目(2016J01734)
作者简介:第一作者:金保明(1970-),男,高级工程师,博士.研究方向:水文水资源.E-mail:jbm720@126.com
引用文本:
金保明,林鹏,李光敦.基于运动波壤中流理论与无限边坡稳定分析理论的滑坡预测模型[J].工程科学与技术,2021,53(4):140-148.
JIN Baoming,LIN Peng,LEE Kwantun.Integrating Kinematic Subsurface-wave Approximation with Infinite-slope Stability Analysis for Landslide Predictions[J].Advanced Engineering Sciences,2021,53(4):140-148.