波浪作用下水下岩质边坡的稳定性

The Stability of Underwater Rock Slope by wave impaction

摘要:

随着大型水利工程的建设，库岸的边坡稳定性问题将形成一个新的研究热点。本研究以探讨波浪冲击作用下水下岩质边坡稳定性和破坏机理为目的，按照常见的岩体结构形式，利用Ansys建立并数值模拟计算几种不同类型的水下岩质边坡模型，；同时还依据三峡水库实际的波浪参数，在波流水槽中进行了边坡模型的冲击试验。通过波浪作用下模型试验和Ansys数值计算的比对分析，水下岩质边坡临水面岩体根据波浪作用对应力影响的特征，可划分成三个区域，每个区域内应力变化规律相同；研究发现水下岩质边坡坡脚处应力集中最大，破坏始于坡脚，并由此产生的塑性区沿结构面逐渐向坡顶发展，这与一般边坡从坡顶逐渐向下发展的开裂破坏形式完全不同；同时得出波浪对水下岩质边坡结构面的影响，将随其倾角的变小而减弱。

Abstract:

With the constructions of large-scale reservoir projects, the problems of the stabilities of the reservoir banks have been becoming the research focus. To investigate the stability and failure mechanism of underwater rock slopes subjected to wave impactions, a finite element program Ansys was used to model and analyze some types of underwater rock slopes according to general rock structural types.Wave impaction tests were also conducted on two rock slope models with different angles in a wave tank which generated similar regular waves as those in three-gorge reservoir. By analyzing and comparing the results of the model tests and numerical simulations, three zones were divided to the rock slopes close to the water with stress changing similarly in each zone. The results show stress concentration occurs to the slope toe, where failure begins. Plastic zone develops upwards along the discontinuity, which is different from the downward failure mode happened to general slopes. It’s also concluded that the effect of the wave on the slope discontinuity decreases with the slope angle.