人工砂云母含量对高海拔寒冷地区特高混凝土拱坝温控防裂影响研究

Study on the influence of artificial sand mica content on temperature control and crack prevention of ultra-high concrete arch dams in high-altitude cold regions

摘要

为研究人工砂云母含量对混凝土结构温控防裂的影响，针对不同人工砂云母含量混凝土，试验测定所有的温控防裂计算参数(徐变除外),并在此基础上进行高海拔寒冷地区特高拱坝温控防裂数值模拟分析。结果表明，云母含量对结构最大应力影响在0.1 MPa左右，对温度峰值影响在0.7℃左右。人工砂云母含量在6.5%~2.9%范围内，云母含量的变化对结构安全系数有较大影响；人工砂云母含量在2.9%以下时，云母含量的变化对结构安全系数影响很小。在设计允许的温控标准内，即使是高海拔寒冷地区特高混凝土拱坝，人工砂云母含量4.5%的混凝土也可以满足规范建议的2.0安全系数。系统性论证了人工砂云母剔除技术可有效提高混凝土拱坝的安全系数，避免人工砂中云母对拱坝的温控防裂造成危害，为保障拱坝安全和增加料原的选择提供支撑，对后续工程的建设有较大的参考价值。

Abstract

To study the effect of artificial sand mica content on temperature control and crack prevention of concrete structures, for concrete with different artificial sand mica contents, all temperature control and crack prevention calculation parameters(excluding creep) were experimentally measured, numerical simulation analysis of temperature control and crack prevention for ultra-high arch dams in high-altitude cold regions was carried out. The research result indicate that the mica content has an impact on the maximum stress of the structure at around 0.1 MPa and on the temperature peak at around 0.7 ℃. The content of artificial sand mica ranges from 6.5% to 2.9%, and changes in mica content have a significant impact on the structural safety factor; When the content of artificial sand mica is below 2.9%, the change in mica content has little effect on the structural safety factor. Within the allowable temperature control standards in the design, even for high-altitude and cold areas with ultra-high concrete arch dams, concrete with an artificial sand mica content of 4.5% can meet the recommended safety factor of 2.0 in the specifications The artificial sand mica removal technology can effectively improve the safety factor of concrete arch dams, avoid the harm of mica in artificial sand to the temperature control and crack prevention of arch dams, provide support for ensuring the safety of arch dams and increasing the selection of raw materials, and have great reference value for the construction of subsequent projects.

关键词

人工砂 / 云母 / 含量 / 混凝土

Key words

artificial sand / mica / content / concrete

Author summay

夏 勇(1984—), 男, 高级工程师, 总工, 硕士, 主要从事水利水电工程研究。E-mail: [e-mail]