丹江口大坝右岸转弯坝段“反向”变形的分析及对策  

Analysis of "reverse" deformation of curved dam section of Danjiangkou dam

作　　者：李贻祖 成振铎 王述圣 

出　　处：《人民长江》1995年第6期11-16,共6页Yangtze River

摘　　要：丹江口水利枢纽混凝土坝右岸１～右３等４个坝段向上游折转６０°，称右岸转弯坝段，在平面上呈向下游凸出的反拱形。运用初期，发现这几个坝段水平变形与其它直线坝段变形方向相反。其后增设监测项目、提高观测精度，全面监测坝体变形、坝基扬压力和坝踵接触面开合情况，经分析表明：转弯坝段＂反向＂变形并非全年发生，每年３～５月仍为正常变形，５～９月坝体升温，与两侧直线坝段热胀撑挤，产生了向下游的挠曲变形，与其他直线坝段相反，这一＂反向＂挠曲９月达最大值，同时坝踵基岩接触面有微小开裂，帷幕前扬压力加大。９月至次年２月热胀挤压力逐渐减小，变形又回复原状，坝踵裂缝逐渐闭合，扬压力降低。为消除坝体长期反复撑挤变形，避免坝踵周期性开裂，保证坝基防渗质量，今后当大坝加高时，应针对＂反向＂变形产生的原因进行有效的处理。建议对初期坝顶附近的灌浆横缝采用锯缝（钻成空缝）处理，下游坡加厚及坝顶加高新浇筑混凝土横缝填软垫层，以消除热胀撑挤作用，进行坝基渗控补强处理，并继续加强安全监测。For the Danjiangkou concrete gravity dam, the dam axis of the right bank dam section composed of the dam block 1￣3 is a curve protruding downstream, and the dam axes of the dam sections composed of other dam blocks are straight line. During the early period of operation, it was observed that the direction of the horizontal displacements of the curved section is opposite from that of the straight dam section. then,additional and more accurate observation works were carried out totally to monitor the displacement of the dam body, the uplift pressure in the dam foundation and the opening/closing of the joint at dam heel between dam and rock foundation. The analysis of observed data shows that the 'reverse' displacement of the curved dam section does not occur in a whole year, and occurs only during the period from June to September, and reaches its maximum value in September, accompanied with micro opening of the joint at dam heel between dam and rock foundation and increased uplift pressure in front of the seepage proof curtail. And, during the period from October to February, the 'reverse' displacement gradually draws back and disappears, accompanied with closing of the joint at dam heel and decreased uplift pressure. During the period from March to May, the direction of the dam displacement of the curved dam section is in agreement with that of the straight dam section. The reason of causing the 'reverse' displacement is the effect of temperature rising in dam body. Thermal expansion of the straight dam sections located at both sides of the curved dam section makes the curved dam section displace downstream. When the Danjiangkou dam is heightened in the future, the improved measures should be taken so as to eliminate such a long-term repeated displacement, avoid the cyclical opening/closing of the joint at dam heel, and ensure the quality seepage prevention in the dam foundation. To be specific, the following improved measures may be taken: (1) to cut the old grouted transverse joints in the vicinity of the cre

关 键 词：坝段 变形观测 安全监测 丹江口 水利枢纽 

分 类 号：TV698.11[水利工程—水利水电工程]