渗流问题是直接影响大坝改扩建后运行安全的关键问题, 为此, 利用三维渗流场的仿真研究, 合理评价大坝改 扩建设计渗控的合理性和有效性是十分必要的。采用无压渗流场仿真计算理论和有限元方法, 在设计渗控措施下, 对某水库加高加固后土坝的三维渗流问题进行仿真计算, 并定性、定量分析了土坝坝区浸润线、水头分布、渗透坡降 及渗漏量等渗流参数的数值规律。结果表明, 混凝土预制块、复合土工膜、防渗帷幕等组成的坝体防渗体系, 可以有 效地截断通过土坝的渗流, 但水库水位的抬高也增加了土坝连接部位的绕渗、渗透坡降等不利渗流的安全问题。

Seepage is the key technical pro blem fo r the eart h dam extension pr oject, and the reasonable ev aluatio n of the r ationali2 ty and validity of seepag e co nt ro l desig n scheme is needed. In this paper, the unconfined seepag e field theo ry and finite element met ho d w ere used t o simulate the thr ee2dimensional seepag e of the ear th dam in a reservo ir after reinfor cement and heightening under t he desig n scheme of seepage co nt ro l. T he char acteristics of the seepag e parameter s, such as infilt ratio n, head distr ibution, seepage g radient, and leakage, w ere analyzed qualitativ ely and quant itativ ely . T he results showed that seepag e thro ug h the dam can be effectiv ely inter cepted under the seepag e co nt rol measures of precast co ncr ete blocks, composite geomembr ane, and seep2 ag e pr evention curtain; how ever, t he unfav orable seepag e safety pr oblems o f by pass seepage and seepag e g radient in the dam junction occur when the r eser vo ir w ater level increases.