两河口水电站库区特大桥边坡稳定性复核与治理  

Slope stability analysis and reinforcement of super river-crossing bridge in reservoir area of Lianghekou Hydropower Station

作　　者：李其虎 LI Qihu(Yalong River Hydropower Development Co.,Ltd.,Chengdu 610051,China)

机构地区：[1]雅砻江流域水电开发有限公司,四川成都610051

出　　处：《人民长江》2023年第2期159-164,共6页Yangtze River

摘　　要：两河口水电站库区哈格达沟特大桥建成后,经勘探复核发现右岸桥基边坡存在软弱破碎层面,电站蓄水后岸坡在库水反复升降浸泡软化及消落的作用下,存在蠕滑变形并局部失稳的风险。综合考虑岸坡岩体和桥梁基础在水库消落运行环境下的相互作用,构建了特大桥右岸边坡稳定性计算模型和设计工况,同时采用摩根斯坦-普莱斯法复核了该部位桥梁及岸坡稳定性。结果表明,蓄水后右岸边坡桥位区浅层卸荷松动岩体可能产生变形失稳。为了预防岩体变形失稳对桥梁墩台的影响,提出了“抗滑桩+锚索”“框格梁+锚索”的综合加固方案。经过处理后的哈格达沟特大桥经受住了近100 m的库水位抬升考验,各项监测数据均满足设计要求,边坡无明显变形,保障了复建道路在蓄水期、水库运行期安全稳定运行。该库区特大桥梁岸坡处理案例可为同类工程处理提供借鉴。After the completion of the Hagedagou Bridge in the reservoir area of Lianghekou Hydropower Station,a weak and broken layer was foundat the bridge foundation slope on the right bankthrough exploration.After the reservoir impounding,the bank slope has the risk of creep deformation and local instability under the effect of repeated drawdown and immersion softening of reservoir water.Considering the interaction between the bank slope rock mass and the bridge foundation under the environment of water drawdown,a slope stability calculation model and design conditions of the river-crossing bridge were constructed.At the same time,the stability of bridges and bank slopes was analyzed by the Morgenstern-Pryce method.The results show that the shallow unloaded loose rockmass in the bridge site of the right bank slope may produce deformation instability after reservoir impounding.In order to prevent the influence of rockmass deformation and instability on bridge pier platform,comprehensive reinforcement schemes of‘anti-slide pile+anchor cable’and‘frame beam+anchor cable’were proposed.The treated Hagedagou Bridge has undergone a reservoir water level uplift test of nearly 100 m.And there is no obvious deformation of the bridge and slope,and the monitoring data meet the design requirements,which has ensured the safety of the reconstructed highway during the reservoir impounding and operation period.This case can provide reference for similar engineering treatment.

关 键 词：边坡稳定性 库水位涨落 刚体极限平衡法 不良地质体 跨江特大桥 两河口水电站 

分 类 号：TV223[水利工程—水工结构工程]