软弱地基上的碾压混凝土拱坝应力与位移分析

Analysis of stresses and displacementfor roller compacted concrete archdam on a weak foundation

某工程在软弱基础上修建的碾压混凝土拱坝坝高大于100m,基础软弱,应力和位移大,尤其是坝肩向下游位移大。提出设置推力墩新结构来增强拱座受力,限制其变形。示例对水压荷载作用下坝体的应力和位移进行三维仿真分析,表明仅设置30m长的推力墩能消减50％的坝体下游面(水压荷载)拱向拉应力;位移减小20％;坝肩基岩几乎处于微压状态,水压应力向推力墩转移,加大坝基底面减小坝体沉陷。由于推力墩结构减小了拱跨度,增强了拱坝的整体性,分担了主要的坝肩荷载,可使拱坝应力得到改善,位移得到控制。

A roller compacted concrete arch dam is over 100m high and the foundation is weak, the deformation and stresses in the arch dam were much larger than normal, especially the abutment displacement downstream. A 30 m long stift pier was added to reinforce the abutment and reduce the deformation. Three-dimensional analyses of the stresses and displacement due to the hydraulic pressure showed that the downstream tensile stresses in the arch dam were reduced by 50% and the deformation was reduced by 20%. The stresses in the foundation near the dam abutment were transmitted mainly through the pier, which enlarged the dam foundation and reduced the sinkage. Since the pier reduces dam span and improves its rigidity, the piers share the load on the dam abutment which reduces the stresses so the deformation is controlled.