邢坦 胡文才 王振红

摘 要：与常态混凝土坝相比，碾压混凝土坝温控防裂措施相对简单，但在气候干燥、温差较大和太阳辐射强的西藏高海拔地区建设碾压混凝土坝将面临着较大的温控压力。针对这一问题，把常态混凝土坝温控防裂的思路和方法应用于碾压混凝土坝的温控防裂，经过方案的优化组合和仿真计算，得到适合高海拔地区大坝施工期温控防裂的目的。该方法以西藏地区某陡坡坝段为例，用三维有限单元法研究其温控情况，筛选出实时合理的温控防裂措施，实际应用效果良好。该方法和措施对类似地区同类工程的建设具有重要指导意义。

关键词：重力坝;碾压混凝土;温控防裂;浇筑温度;水管冷却

中图分类号：TV315 文献标志码：A

doi：10.3969/j.issn.1000-1379.2020.02.028

Abstract：Compared to the normal concrete dam， temperature control methods for cracking prevention of roller compacted concrete （RCC） dam are quite simpler， however， great challenges still exist for the dam construction in Tibetan area with high altitude， dry climate， large daily temperature difference and intense solar radiation. Based on the temperature control methods applied for normal concrete dams， an optimized temperature control and cracking prevention for RCC dams at high altitude areas was proposed. A steep slope dam segment in Tibet was taken as an example to verify the optimized method. Three-dimensional finite element method was employed to investigate the cracking sensitivities of dam segment under different temperature control methods and suitable temperature control measures were recommended and applied for actual dam construction. The effectiveness of these methods had been confirmed by the on-site inspection. The method and measures have important guiding significance for the similar projects in similar areas.

Key words： gravity dam; roller compacted concrete; temperature control and crack prevention; casting temperature; water pipe cooling

1 前 言

从美国的胡佛大坝开始，如何防止混凝土坝裂缝的产生已受到工程建设者的重视，并做了大量工作防止裂缝产生，特别是防止温度裂缝的产生[1-2]，取得了不少成就[3-6]，胡佛大坝的水管冷却技术至今仍然被广泛应用。但到目前为止，国内外的混凝土坝依然会或多或少地产生裂缝[7-9]，危害性裂缝影响结构的承载力、防水性、耐久性和使用寿命，而且裂缝的处理将是一件既费时又耗资的事。施工前做好混凝土裂缝的预防对于确保工程质量非常重要[10-11]。

随着科学技术的发展，碾压混凝土坝越来越被广泛采用，因其良好的性能和经济的投资得到了大家的青睐[12-14]。随着工程建设者要求的提高，碾压混凝土中水泥掺量越来越多，掺合料也越来越多，不同部位的混凝土配合比差距比较明显，而简单的施工方法和简化的温控措施是建设者所期望的。……