摘要
本文用Duncan非线性模型和笔者建议的双屈服面弹塑性模型(简称南水模型),分析了黄河小浪底水库大坝设计断面住施工和蓄水过程中的有效应力和变形状态。按Duncan模型计算的竣工期变位,显著大于按弹塑性模型的计算结果,但所计算的孔隙压力却较低。此外,Duncan模型计算的施工期斜墙的水平位移很大,这是上游坝体在雨水浸透情况下稳定性不够的反映。两种模型的最大差别反映在蓄水期计算结果上。按Duncan模型,蓄水将使坝顶显著地向下游水平位移,且有相当大的上抬;按弹塑性模型,坝顶向上游移动,其垂直变位为下沉。两种模型的计算结果均表明,防渗墙顶部及附近土体中无水力劈裂的迹象,但水库运行初期淤积体内有相当高的超静孔隙压力,50年后则大部分消散。计算的施工期防渗墙垂直应力不大,但水库蓄水后有显著增加。
In this paper the Duncan's nonlinear model and a double hardening model newly developed by the first author have been used to predict the movement and pore pressure responses of 157m high Xiaolangdi dam during construction, reservoir impounding and deposition which will be erected in the main stream of Yellow River in the near future. The movements predicted with Duncan's model are considerably larger than those predicted with the author's model, but oppositely, the construction pore pressure predicted with former is somewhat lower. The horizontal movement of sloping core at the end of construction predicted with Duncan's model is particularly large, and this may be explained by its low stability when fully saturated in the rainy season. For the stage of the reservoir impounding the Duncan's model predicts considerably large downstream and upward movement of dam crest, while the author's model predicts a moderate downstream and yet downward movement. Both models predict no possibility of hydraulic fracture of cort material near the top of diaphragm wall but there does exist high pore pressure in the reservoir deposition remaining undissipated in many years. The vertical stress in diaphragm wall is not so high at the end of construction, but will increase considerably after reservoir impounding.
