摘要
在严寒地区修建混凝土拱坝,超低极端气温、超大年内温差和冬季突发寒潮等环境温度荷载是造成混凝土结构拉裂破坏的重要因素,因此开展长期保温防裂措施的研究意义重大。采用等效原理,提出了保温层-混凝土复合材料的热传导等效模拟概念,建立了有限元数值仿真中不同厚度混凝土与表面保温层等效单元;利用严寒地区长期实测资料和同类工程经验,选定结构数值仿真的气温、水温和材料热力学参数,开展温降工况下不同保温层厚度的坝体温度场及应力场数值计算与分析。结果表明:严寒地区坝体在无保温层时的坝体表面混凝土温度变化规律与气温基本相同,采取保温措施后保温层对坝体表面的保温效果较为明显,保温效果随保温层厚度的增加而增强;无保温层时上下游坝面出现大面积的拉应力区,增加保温层后坝体的拉应力区有所减小且应力随保温层厚度的增加而逐渐减小。
To build concrete arch dam in severely cold regions,the influences of environmental temperature loads,such as extreme cold tem perature,huge year temperature difference and sudden cold wave in winter,are considered as key factors for tensile failure of concrete struc tures.Thus,it is of great significance to carry out long term thermal insulation and crack prevention research.In this paper,the equivalent u nit of different thicknesses concrete and surface insulation layer in finite element numerical simulation was established by using the equivalent principle.The calculation method of unit equivalent heat release coefficient was proposed.The temperature,water temperature and material thermodynamic parameters of the structural numerical simulation were selected by using the long term measured data and similar engineering experience in the severely cold area.The numerical calculation of the temperature field and stress field of the dam body with different thick ness insulation layer under temperature drop conditions was carried out.The analysis results show that the change of concrete temperature on the surface of the dam body without insulation layer in the cold area is basically the same as the temperature.After the insulation measures are taken,the effect of the insulation board on the surface temperature of the dam is obvious,and the effect depends on the thickness of the insu lation board.When there is no insulation layer,a large area of tensile stress area appears on the upstream and downstream dam surface.After the insulation layer is increased,the tensile stress area of the dam body is reduced and the stress value decreases with the increase of the thickness of the insulation layer.The research results provide reference for the insulation of similar projects.
作者
黄丹雏
何明明
黄梓莘
罗舜
HUANG Danchu;HE Mingming;HUANG Zishen;LUO Shun(College of Water Conservancy and Hydropower Engineering,Hohai University,Nanjing 210098,China;State Key Laboratory of Hydrology Water Resources and Hydraulic Engineering,Hohai University,Nanjing 210098,China)
出处
《人民黄河》
CAS
北大核心
2020年第4期148-151,160,共5页
Yellow River
基金
国家自然科学基金重点资助项目(U1765204)。
关键词
严寒地区
混凝土拱坝
等效放热系数
保温层
温度应力
severely cold
concrete arch dam
equivalent exothermic coefficient
thermal insulation layer
temperature stress
