抽水蓄能电站内加强月牙肋岔管围岩分担内水压力设计
[摘要] 埋藏式岔管国内外基本按明管设计，围岩分担内水压力仅作为一种安全储备。西龙池抽水蓄能电站岔管PD值远超过国内已建工程规模，在国内首次采用考虑围岩分担内水压力设计。本文重点介绍西龙池岔管考虑围岩分担内水压力设计成果。首先通过三维有限元结构分析，较系统研究岔管围岩分担内水压力的规律，并初步提出埋藏式岔管的设计原则；通过1:2.5比尺的现场结构模型试验验最终确定埋藏式岔管设计参数和验证有限元计算成果。 ［关键词］抽水蓄能电站 西龙池 内加强月牙肋岔管 围岩分担内水压力设计 Design of Assuming Surrounding Rock to Share Internal Water Pressure for Escher-Wyss Wyepiece at Xilongchi Pumped Storage Power Station WANG Zhiguo [Abstract] Buried bifurcated pipes have been designed normally as exposed ones,in which,sharing internal water pressure with surrounding rock is taken as a safe reserve only.With a PD Value of far more than those in the existing domestic projects,this project adopts firstly the design assuming surrounding rock to share internal water pressure.This paper describes mainly the design results.In this paper,Law of sharing internal water pressure with surrounding rock is investigated systematically by means of 3D finite element structural analysis to give preliminary design principles for buried bifurcated pipes,and through the testing on a 1:2.5 site structure model,the design parameters are determined finally and the calculated results of EFM are demonstrated. [Key words] Xilongchi pumped storage power station, Escher-Wyss wyepiece,Design of assuming surrounding rock to share internal water pressure 西龙池抽水蓄能电站岔管PD值达3552.5m2，远超过国内已建工程规模，在世界上也位于前列，如按传统方法即明管设计，管壳和肋板较厚，将会使岔管制造、安装难度较大，为此考虑围岩分担内水压力设计。国内外埋藏式岔管基本按明管设计，围岩分担内水压力仅作为一种安全储备。对于大PD岔管考虑围岩分担内水压力，减小钢板厚度的意义不仅在于节约钢材用量，更重要的是降低岔管制安难度。以往有些工程也不同程度地考虑围岩分担内水压力的潜力，如以礼河三级电站斜井式调压井的分岔结构、渔子溪一级电站三梁岔管等，这些经验作法纳入《水电站压力钢管设计规范（试行）》(SD144-85)，通过提高10%～30%允许应力来间接地反映围岩分担内水压力的作用。在岔管的实际运行状态下，内水压力是通过变形协调，实现围岩与钢岔管共同分担的。通过对已建工程岔管的原型观测资料分析发现岔管应力并不高，证明围岩分担内水压力的作用是明显的。关于岔管围岩分担内水压力设计国内外尚处于探索阶段，如何考虑围岩分担内水压力的作用，还没有较成熟的方法。目前仅有日本的奥美浓电站的内加强月牙肋岔管，进行了围岩分担内水压力设计尝试，由于是首次尝试，缺乏经验，设计时围岩分担率限制在15%以下［6］，而原型观测结果表明，围岩分担率远大于15%，围岩分担作用是相当明显的。 下载全文： |
