堰塞坝水力驱动溃滑过程模拟方法研究
Simulation Method of Hydraulically Driven Breaking-sliding Process for Landslide Dam
作者：王琳(西安理工大学 省部共建西北旱区生态水利国家重点实验室, 陕西 西安 710048)；段庆伟(中国水利水电科学研究院 岩土工程研究所, 北京 100048)；孙平(中国水利水电科学研究院 岩土工程研究所, 北京 100048)；张强(中国水利水电科学研究院 岩土工程研究所, 北京 100048)；刘立鹏(中国水利水电科学研究院 岩土工程研究所, 北京 100048)；王乃欣(中水北方勘测设计研究有限责任公司, 天津 300222)
Author：WANG Lin(State Key Lab. of Eco-hydraulics in Northwest Arid Region of China, Xi'an Univ. of Technol., Xi'an 710048, China)；DUAN Qingwei(Dept. of Geotechnical Eng., China Inst. of Water Resources and Hydropower Research, Beijing 100048, China)；SUN Ping(Dept. of Geotechnical Eng., China Inst. of Water Resources and Hydropower Research, Beijing 100048, China)；ZHANG Qiang(Dept. of Geotechnical Eng., China Inst. of Water Resources and Hydropower Research, Beijing 100048, China)；LIU Lipeng(Dept. of Geotechnical Eng., China Inst. of Water Resources and Hydropower Research, Beijing 100048, China)；WANG Naixin(BeiFang Investigation, Design and Research Co. Ltd., Tianjin 300222, China)
收稿日期：2019-03-12 年卷（期）页码：2019,51(4):37-46
期刊名称：工程科学与技术
Journal Name：Advanced Engineering Sciences
关键字：堰塞坝;滑裂面;有效应力法与总应力法;溃滑过程
Key words：landslide dam;slip surface;the effective versus total stress analysis;breaking-sliding process
基金项目：国家重点研发计划项目（2017YFC1501103）；陕西省自然科学基础研究计划（2019JQ-577）
中文摘要
为评估堰塞坝安全，需要分析其受水力驱动溃滑导致的溃决变化过程。传统的分析方法或没有运用极限平衡法，或认为溃滑过程中其滑裂面倾斜角度不变，或没有考虑孔隙水压力。实际中，堰塞坝水力驱动溃滑过程是一个需要由极限平衡理论解决的问题。通过采用岩土工程中圆弧形式的边坡稳定分析方法，考虑孔隙水压力影响，运用总应力法和有效应力法模拟堰塞坝不断溃滑的过程（包含溃口横向的不断扩展过程及其垂直下切过程）；开发DBS-IWHR的电子表格分析堰塞坝溃滑过程，该电子表格已被耦合到溃决洪水分析电子表格DB-IWHR，用于分析其受水动力驱动溃滑导致的溃决洪水变化过程。结果表明：1）DBS-IWHR提出确定堰塞坝水力驱动溃滑过程的模拟步骤：确定特定圆弧滑面的安全系数FS；在各种可能的滑裂面中，确定与最小安全系数Fm相关的临界滑裂面；确定与Fm=1相关的坡脚失稳的临界深度；连续溃滑过程的模拟。以上过程只需手动4步即可进行溃滑过程模拟，基于VBA编制的程序具有良好的交互性，利于读者和使用者进行矫正和二次开发。2）选取唐家山案例，分析了水动力驱动溃滑过程及溃决洪峰流量过程，其洪峰为6 500 m3/s，溃口宽度为150 m；预测的溃决洪峰流量为7 610 m3/s，溃口宽度为139.6 m。预测值与实测值的误差在允许范围内，验证了改进的水力驱动溃滑过程模拟方法的可靠性。
英文摘要
Valuating breach flood of landslide dam is usually through analyzing the breach process caused by hydraulically driven breaking-sliding process.The traditional analytical method does not use the limit equilibrium method, or the slope angle of the slip surface is not changed during the collapse process, or the pore water pressure is not considered. In fact, the hydraulically driven breaking-sliding process is a problem that needs to be solved by the limit equilibrium. An approach to determine the critical slip surface by analytical method with circular slip surfaces, the effective and total stress methods dealing with different dam materials, and a procedure to model the stepped failures of the breaking-sliding process due to continuous toe cutting were proposed. A spreadsheet entitled DBS-IWHR was developed to the breaking-sliding process analysis. This spreadsheet was incorporated into another spreadsheet entitled DB-IWHR for the calculation of flood hydrograph caused by hydraulically driven breaking-sliding. Research indicated that DBS-IWHR proposed a simulation step to determine the hydraulically driven breaking-sliding process of the dam, which included finding the factor of safety for a specific circular slip surfaceFS; among a variety of possible slip surfaces, determining the critical one associated with the minimum factor of safetyFm; determining the critical depth of toe cutting associated withFm= 1; modeling the stepped breaking-sliding process. The simulation of the collapse process could be performed in four steps manually. The spreadsheets are transparent and self-explanatory, easy for practitioners to understand and check for secondary development through the web. The developed approach was tested by back analysis of the Tangjiashan landslide dam breached in 2008 with a flood peak of 6 500 m3/s, breach width of 150 m. The predicted flood peak is 7 610 m3/s and the breach width is 139.6 m. The calculated results of the final breach base level and the peak discharge were in good agreement with the field data. Further, the results were shown to verify the reliability of the improved hydraulically driven breaking-sliding process simulation method.
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