玛尔挡水电站泄洪雾化数学模型研究

Study on mathematical model of flood discharge atomization for Maerdang Hydropower Station

玛尔挡水电站地处高山峡谷地区、两岸岩体地质情况较差,挑流泄洪雾化可能对两岸边坡及交通安全产生不利影响。为准确预测泄洪雾化水流的影响范围和程度,结合蒙特卡罗方法考虑环境风和地形因素的随机喷溅数学模型,对玛尔挡水电站在水舌风和汛期最不利自然风两种情况下3个典型工况的雾化情况进行了计算和分析。研究结果表明:泄洪雾雨主要沿边坡竖向爬升,只考虑水舌风时,下游雾化降雨范围最远到达坝下1 021 m,横向左扩散至3 190 m高程,横向右扩散至3 160 m高程。水舌风和自然风共同作用时,各泄洪组次雾化范围沿自然风向偏移,左右岸影响范围收窄。根据暴雨分布范围,建议适当增加下游两岸边坡的防护长度和高程。雾化降雨对省道S101没有影响,但左岸导流洞出口导墙段区域和右岸进厂交通洞口位于薄雾降雨区,泄洪时应禁止通行。

As Maerdang Hydropower Station is located in an alpine-gorge area with poor geological conditions on both the banks,an adverse impact is possibly produced from the atomization caused by the trajectory bucket flood discharge on the slope stabilization and traffic safety therein. In order to accurately predict the impacting range and extent of the atomized flow from the flood discharge,the atomization statuses of three typical operation conditions of Maerdang Hydropower Station under two situations of both the nappe-wind and the most unfavorable natural wind in flood season are analyzed and calculated under the consideration of the environmental wind and topographic factors in combination with the Monte-Carlo method. The study result shows that if only the nappe-wind is considered,the atomized rain caused by the flood discharge mainly climbs up vertically along the side slope,while its downstream range reaches as far as 1 021 m from the dam with the left transverse diffusion to the elevation of 3 190 m and the right transverse diffusion to the elevation of 3 160 m. Under the common effect of both the nappe-wind and the natural wind,the atomization ranges of all the group-sets of flood discharge are deflected along with the direction of natural wind,and then the impacted ranges on both the banks are narrowed. In accordance with the distribution area of rainstorm,it is suggested to appropriately increase the length and the elevation of the slope protection for both the downstream banks. The atomized rainfall has no any impacts on the provincial highway S101,however,as the area of the guide-wall section at the outlet of the left bank diversion tunnel and the portal of the powerhouse traffic tunnel at the right bank are located within the area of thin atomized rainfall,the traffic therein must be prohibited during flood discharge.