关于大坝扬压力及其降低措施的几点思考

非洲某碾压混凝土重力坝最大坝高120m,坝顶长度1164m,混凝土总量353万m^3。该大坝基础地质情况复杂,河床坝段坝基为寒武纪辉绿岩,两岸坝肩为奥陶纪砂岩,地质条件复杂,导致大坝稳定性分析和基础处理难度均较大。在与国际咨询工程师讨论大坝抗滑稳定性问题过程中,深感双方在扬压力及其降低措施等观念上存在差异。文章重点阐述扬压力形成的原理和本工程对于不同地质条件降低扬压力所采用的措施。

The maximum height of a roller compacted concrete gravity dam in Africa is 120 m,the length of the top of the dam is 1164 m,and the total amount of concrete is 3.53 million m3.The geological conditions of the dam foundation are complex,the dam foundation of the riverbed dam section is Cambrian diabase,and the abutment of the dam is Ordovician sandstone,and the geological conditions are complex,which leads to the difficulty of dam stability analysis and foundation treatment.In the course of discussing the anti-sliding stability of the dam with the international consulting engineers,it is deeply felt that there are differences between the two sides in the concepts of uplift pressure and its reduction measures.This paper focuses on the principle of uplift pressure formation and the measures adopted in this project to reduce uplift pressure under different geological conditions.