小浪底土石坝三维地震反应分析

Three-dimensional Analysis on Earthquake Response of the Xlaolangdi Earth-Rockfill Dam

根据小浪底斜心墙堆石坝坝基砂砾石以及有关坝料在循环荷载作用下的孔隙水压增长模型以及残余变形模型，对该坝进行二维地震反应分析。地震加速度时送线是根据世界银行咨询专家为小浪底提出的地震反应谱经过人工合成得到的。分析结果表明，在地震作用下，虽然坝踵砂砾石地基以及上游淤积土表层均有一定范围的液化破坏区，但由于坝唾液化区离大坝坝体较远，因而只影响到坝踵压戗的局部；上游反滤层局部区域有破坏的可能，但由于区域较小，与渗透性良好的堆石体相邻，对坝体不构成威胁。

ccording to the model of pore water pressure growth under cyclic loading for gravel and relevant materials in the dam foundation and the model of permanent deformation, a threedimensional earthquake response analysis was performed for the sloping core earth-rockfill dam of the Xiaolangdi Multipurpose Dam Project. The curve of earthquake accleration process was composedsynthetically from the earthquake response spectrum provided by the consulting experts of theWorld Bank. An analysis indicates that even though Liquefaction zones exist in the gravel base of;the dam heel and the surface layer of the deposition at the upstream, these zones are at a distancefrom the main dam body. Therefore. the influence will be limited to part of the rockfill buttress atthe dam heel. Possible failure may also be induced in some upstream regions of the filter layer.Nevertheless, the failure area is minimal and its location is adjacent to the rook fill zone. which hasa good permeability. Thus, the dam body is not in danger.