滑坡速度计算及涌浪预测方法探讨

Discussion on method of landslide velocity calculation and surge prediction

滑坡滑动速度的计算是涌浪预测的基础。在考虑滑坡入水条块受水阻力的基础上,对计算滑速的美国土木工程师协会推荐公式和运动方程方法进行改进,并以三峡库区秭归县下土地岭滑坡为例,计算了滑坡下滑过程中的平均速度及各条块的加速度、速度,对比分析了考虑水阻力前后加速度、速度大小、变化规律,并计算了滑坡下滑激起的初始涌浪高度。结果表明,考虑滑坡入水条块所受的水阻力,更符合滑坡运动过程中的实际受力情况。且水阻力对于滑坡运动的加速度、速度有较大影响,没有考虑水的阻力时,随着入水条块的增多,加速度先增大后减小,且变化趋势不会反弹;考虑水阻力后,由于水阻力大小和滑坡速度及坡面的迎水面积均相关,在两种因素综合作用下,加速度有可能在出现减小趋势后再增大。

The calculation of sliding velocity of landslide is the basis of surge prediction.On basis of considering the resistance of water,the formulas advised by The American Society of Civil Engineers and movement equation method are improved.Taking the Xiatudiling landslide in the Three Gorges Reservoir of Zigui county for example,the average velocity and each slice’s acceleration,velocity in the process of sliding are calculated;the comparative analysis about the value and change law of acceleration,velocity is made between pre and post considering the water resistance;and then,the height of initial surge evoked by the landslide is calculated.It is concluded that considering the water resistance to slices entering water is more coincident to practical force condition.The water resistance has great influence on the acceleration,velocity of landslide.When the water resistance is not considered,with the increasing of numbers of slices entering water,the acceleration of landslide increases firstly,then it decreases,and the tendency will not rebound.When the water resistance is considered,the value of water resistance is related with velocity of landslide and area of slope surface;under the comprehensive effect of these two factors,the acceleration of landslide may increase after its decreasing tendency.