软化砂砾岩上的拱坝新结构

Arch dam design for soft sandy gravel foundation

为在砂砾软岩上经济、快速地修建拱坝,针对软岩强度低、变形大的特点,分析了水压和累积自重作用下软岩上的拱坝受力和变形规律,提出了以下工程策略:上游坝面周边设置人工拱面缝释放岩石拉应力,缝端用槽钢止裂;下游布置推力墩增强坝肩,限制变位;扩大基础均化坝体由自重产生的压应力集中。结果表明:在软岩上采取上游面设置人工拱面缝释放拉应力,下游面设置推力墩限制变位的措施后,拱坝及其周边岩石能够满足内应力及承载力要求。

The design of arch dams sited on sandy-gravel foundations was analyzed to determine methods to ensure dam stability. The soft foundation is weak and easily deformed which will affect the stress distribution and the deformation of the arch dam structure. Several remedial measures that will stabilize the structure include building artificial arch face short joints around the upstream perimeter to reduce the tensile stress concentration in the rock with the stability of the edges secured by the steel rods. Concrete piers at both sides of the downstream dam will strengthen the abutment and minimize displacement. The bottom of the dam should also be enlarged to reduce the compressive stress concentration near the upstream heal of the dam due to the dam weight. With these measures, the interior stresses and the bearing capacity of the dam and its peripheral rock will be within sofe limits.