不同库水位升降速度对大坝边坡稳定性的影响研究

Study on impactfrom various reservoir water level fluctuation rates on dam slope stability

为了提高水库的安全管理水平,以极限平衡为理论基础,使用GEO-SLOPE软件中的SEEP/W模块和SLOPE/W模块,分别计算了某水电站水库右岸边坡土体在不同水位升降速度情况下边坡稳定安全系数的变化规律。结果显示:在正常蓄水状态下,边坡稳定安全系数曲线变化趋势是先降低,然后升高,随后曲线趋于稳定。水位上升速率越快,边坡土体稳定安全系数越高,边坡越趋于稳定。但当蓄水速度超过一定数值时,边坡稳定性会降低。当库水位降低时,边坡稳定安全系数先降低,到达极小值之后再平稳上升。因此,为了保证大坝边坡的稳定,在建设水库中,水库在蓄水和排水过程要随时监测边坡内部的结构面状况;在水库运行调度中,应合理控制水位升降的速度。

In order to enhance the safety management level of reservoir,the changing law of the slope stability safety factor of the soil mass on the right bank of the reservoir for a hydropower station under various water level fluctuation rates are calculated with the modules of SEEP/W and SLOPE/W in the software of GEO-SLOPE respectively on the basis of the limit equilibrium theory.The result shows that under the normal storage condition,the changing trend of the curve of the slope stability safety factor is to be lowered at first and subsequently raised,and then tends to be stable.The quicker the water level raising rate is,the higher the slop stability safety factor is to be and the more stable the slope is to be.However,when the storage rate surpasses a certain value,the slope stability is to be lowered.During the lowering of the reservoir water level,the slope stability factor is lowered at first and then stably raised after reaching its minimum value.Therefore,for ensuring the dam slope stability during the construction of the reservoir,the status of the structural plane inside of the slope must be monitored at all time during the storage and discharge of the reservoir,while the water level fluctuation rate must be reasonably controlled during the operation of the reservoir as well.