雅鲁藏布大峡谷水电开发对边坡稳定性的影响

Effects on Slope Stability of the Yarlung Tsangbu Grand Canyon under Future Hydropower Development

雅鲁藏布大峡谷蕴藏着十分丰富的水能资源,未来水电开发对满足国内能源需求和应对气候变暖都具有重要的战略意义,但可能对其边坡稳定性产生不利影响。野外调查发现,基岩河床下切促使大峡谷内崩塌、滑坡、泥石流等地质灾害频繁发生,大峡谷内巨大水流能量与河床结构消能保持微弱的临界平衡状况,河床结构(瀑布和阶梯深潭系统)的消能作用对维持边坡稳定性起至关重要作用。针对梯级高坝和引水隧洞的两种水电开发方案分析表明,两种方案对边坡稳定性均会产生不利影响,且前一种方案的影响更强烈。只有充分认识未来水电开发对大峡谷边坡的影响,才能将水电工程的不利影响减少到最小。

Yarlung Tsangbo Grand Canyon in southeastern Tibet of China possesses very abundant hydropower resources, where future hydropower development is of strategic importance to meet domestic energy demand and response climate warming, but may adversely affect the slope stability of the canyon. Field investigations indicate that bedrock incision of river bed prompted too many avalanches, landslides and debris flow occurring frequently in the canyon. The interaction between huge flow energy and riverbed structures （e. g. cascades and step-pool system） maintains the weak critical balance to hold the stability of the canyon. Two hydropower development schemes which include several steps hydropower plants and long distance diversion tunnels may have direct adverse effects on the canyon stability. Only fully understanding the impact of future hydropower development on the slope stability of the canyon, the adverse effects of the hydropower projects can be reduced to a minimum.