巴东新城区典型库岸深部稳定性分析

Deep stability analysis of typical reservoir bank in Badong county

为了分析巴东新城区库岸斜坡蓄水后的深部稳定特征,首先,选择巴东新城区扇形斜坡中轴线的白土坡库岸作为典型库岸,以深300余米深部监测钻孔岩芯资料为依据,根据软弱带分布、岩体完整性及岩性特征对深部岩体结构分带;然后,基于各带内岩体的地质强度参数GSI,应用Hoek-Brown准则估算岩体强度参数;最后,采用FLAC数值模拟方法分析了库岸斜坡蓄水后的稳定性特征。结果表明:随着水位的上升斜坡稳定性有下降趋势,但下降值并不明显,白土坡库岸斜坡处于整体稳定状态;当强度折减值至极限状态时,剪应变增量值集中区位于6~10层软弱带集中分布的岩层内,受地震作用时剪应变增值集中区向斜坡深部发展,斜坡潜在滑动面顺层发育;斜坡失稳的前提是前缘向斜反倾段完全塑性贯通。

In order to analyze the deep stability characteristic of bank slopes in new Badong county after reservoir storage,firstly,the Baitu slope whicn is on the medial axis of sector of Badong new county is selected as a typical slope,based on the monitoring data of drilling which is more than 300 meters deep the zonation of deep rock structure is done according to the distribution of weakness zone,rock and integrality,lithologic characteristics.Then,based on the geological strength index GSI,the Hoek-Brown rule is used to estimate the rock strength parameter.Finally,the FLAC numerical simulation is applied to analyze the stability characteristic of the bank slope after reservoir storage.It is concluded that the stability appears to decrease with the rising of water level,but it is not obvious,Baitu slope is in integral stable status.When the strength reduces to limit state,the shear strain increment zones locate in the sixth to tenth weakness zone,when the earthquake effect is considered,the shear strain increment zones expand to the deep part of slope,the potential sliding surface develops consequently to layers.The precondition of failure is the plasticity transfixion of anti-dip part in the front of slope.