冬奥会延庆赛区造雪引水工程潜在泥石流灾害模拟与对策研究

NUMERICAL SIMULATION AND COUNTERMEASURES OF POTENTIAL DEBRIS FLOW DISASTERS IN YANQING COMPETITION AREA OF OLYMPIC WINTER GAMES BEIJING 2022

2022年北京冬奥会延庆赛区造雪引水工程是赛区重要的配套工程,担负着为赛区造雪系统提供储水及供水的任务。受工程功能和场区地形地貌条件约束,工程场区主要水工设施面临较高的泥石流风险。针对目前利用泥石流动力学数值模拟方法难以考虑多种降雨条件下泥石流启动厚度以进行多情景泥石流灾害模拟预测的问题,基于雨洪法,本文提出了考虑多降雨重现期泥石流沟平均产水厚度和物源平均产石厚度两个指标及计算公式,并结合无人机精细测量、遥感解译、现场调查、Massflow等手段工具,开展了冬奥会延庆赛区造雪引水工程在不同降雨重现期下潜在泥石流灾害的模拟预测。结果表明:不同高程处的水工构筑物(塘坝和泵站)在不同降雨重现期(20 a、50 a、100 a)下受泥石流威胁的程度存在差异,其中1050塘坝泥石流风险最高,面临淤埋和冲击双重破坏;900塘坝和1290蓄水池泥石流风险次之,前者以淤埋破坏为主,后者以冲击破坏为主;900泵站和1050泵站泥石流风险较低。结合模拟分析和现场调查,建议在1050塘坝上游修建拦砂坝,在900塘坝库尾设置沉砂池,在1290蓄水池东侧修建导流槽,以保障水工设施长期安全运行。

In Yanqing Competition Area of Winter Olympic Games Beijing 2022,the snow making and water diversion project is an important supporting project,which is responsible for water storage and water supply in the competition area.Due to engineering functions and topography conditions,the engineering site area is a favorable geological environment for debris flow disaster,and the main hydraulic facilities are faced with high risk of debris flow.At present,it is difficult to use debris flow dynamic numerical simulation method to simulate and predict sediment erosion thickness under multiple rainfall conditions.In terms of this issue,we propose two indexes:the mean thickness of water yield in debris flow gully and the mean thickness of stone produced by source under different rainfall recurrence periods.And we simulate and predicte the potential debris flow disaster in engineering area with UAV measurement,remote sensing interpretation,field investigation and Massflow.The results show that hydraulic facilities(damp and pumping stations)at different elevations face different debris flow threats,under different rainfall recurrence periods.The debris flow risk of 1050 dam is the highest,facing the double damage of siltation and alluvial,followed by the debris flow risk of 900 pumping station and 1290 reservoir.The former is mainly siltation damage,the latter is mainly alluvial damage.The risk of debris flow is low at pump station 900 and pump station 1050.Based on simulation analysis and field investigation,it is suggested to build a sand dam upstream of 1050 reservoir,a diversion channel on the east side of 1290 reservoir,and a sand settling basin at the end of 900 reservoir to ensure long-term safety operation of hydraulic facilities.