西南某水电站厂房上游侧后坡变形体稳定性研究

Stability of Upper-river Slope Deformation Body behind Some South-West Hydro electric Station Powerhouse

电站厂房上游侧后坡受施工排水、边坡开挖等综合因素的影响,形成了规模巨大的变形体,其稳定性直接威胁了厂址的安全,为此对变形体进行了地质钻探、物探、地面三维变形监测和稳定性计算等研究.结果表明:变形体为整体推移式、局部牵引式的蠕变滑移;从成因和机理分析,施工排水和降雨是诱发形成的最主要因素;其天然稳定性随着降雨量的变化而呈周期性变化,雨季的稳定性差,旱季有所提高,但在饱水或地震条件下,存在失稳的可能.

The large scale deformation body has formed at the upper-river slope behind some south-west hydroelectric station powerhouse,influenced by construction drainage and slope excavation.Its stability threatens the safety of powerhouse lo cation directly.Therefore,geological drilling,geophysical prospecting,3D mon itoring at surface and stability calculation have been carried on for the deform ation body.The results show that the deformation body takes on whole processing and local traction creep sliding.As far as the forming causes and mechanism is concerned,construction drainage and rainfall are key factors.The stability of deformation body presents seasonal variety with the change of rainfall.Its sta bility is bad in monsoon and better in dry season.While its stability will be bad on the condition of saturated water and earthquake,even be unstable.