自重与初次蓄水对特高拱坝应力的影响

以小湾拱坝为例,对不同自重施加方式及初次蓄水条件下大坝的应力进行了三维数值仿真分析。对不同施工方案的应力对比研究结果表明,自重施加方式、封拱灌浆过程及初次蓄水均对坝体应力分布有较大影响,自重全部由梁承担过小地估计了坝体上游拉应力,而整体施加自重、水压时,计算得到的拉应力偏大,从计算精度考虑,小湾拱坝应力计算按10次以上的分期浇筑、分期封拱及分期蓄水过程模拟为宜。

Influence of Construction and Impounding Process on the Stress of Super High Arch Dam

The 3D digital simulation of the stresses of Xiaowan arch dam under different self-weight exaction ways and initial impoundment process has been done.The comparison and research on the stresses under different construction schemes showed that self-weight exaction ways,closed-arch grouting and initial impoundment all greatly affected the stress distribution of dam body.If self-weight is considered to be borne by beam,the upstream tensile stress of dam body will be estimated on the low side but when whole self-weight and water pressure are considered,the calculation value of tensile stress will be on the high side.Therefore viewed from the calculation accuracy,the stress calculation of Xiaowan Arch Dam should be done according to more than ten placements by stage,close arch by stage and impoundment by stage.