摘要
不分横缝、整体浇筑拱坝是近年来推动堆石混凝土拱坝快速发展的新型筑坝技术,非均质堆石混凝土材料的等效参数取值是全拱坝温度仿真前亟待解决的问题。本文依托风光拱坝工程开展了施工期原型温度监测试验,并通过分析堆石与自密实混凝土的温度演化规律,进行了等效均质堆石混凝土温度仿真研究。试验结果发现,入仓的堆石体对下层已浇筑的堆石混凝土存在“保温效应”;自密实混凝土浇筑后会引起下层已浇筑堆石混凝土二次温升,但影响深度不会超过每仓厚度;气候温和地区冬季,堆石体入仓温度比日平均气温高约2.0~4.0℃。结合仿真计算发现,堆石混凝土早龄期温度是从非均匀场向均匀场演化的过程,自密实混凝土入仓时会迅速与堆石进行热交换,水化反应开始后堆石会不断吸收自密实混凝土水化热,经过约48 h达到温度峰值后,两种材料的温度场接近均匀分布。采用均质模型及等效入仓温度、加权导热系数、等效绝热温升,考虑拱坝上下游预制块模板与防渗层等结构开展施工期温度仿真,能较好地模拟堆石混凝土水化过程的等效均匀温度场。拱坝体型相对较薄、散热快,筑坝材料堆石混凝土实测水化温升低(冬季仅约6℃),有力支撑了整体浇筑堆石混凝土拱坝的可行性。
The integrally-poured arch dam without transverse joints is an innovative construction technique that has promoted the rapid development of rock-filled concrete(RFC)arch dams in recent years.The determination of the equivalent parameters for heterogeneous RFC is an urgent issue to be solved before conducting temperature simulations of full-scale arch dams.In this study,based on the Fengguang arch dam project,on-site temperature monitoring experiments were conducted during the construction period,to analyze the temperature evolutions of the rockfill and self-compacting concrete(SCC).Additionally,a homogeneous RFC numerical model was proposed and simulated using the finite element method(FEM)to further investigate the temperature behaviors.The experimental results showed that the pre-laid rocks have a“thermal insulation effect”on the poured RFC beneath.After pouring of the fresh SCC,a secondary temperature rise occurs in the lower-layer poured RFC,but the influence depth does not exceed the thickness of each lift.In mild climate regions during winter,the estimated placement temperature of the rockfill body is about 2.0 to 4.0℃higher than the daily average air temperature.Combining the on-site findings with the FEM simulation results,it was observed that the early-age temperature of the RFC evolves from a non-uniform field to a uniform field.Once the SCC is poured,it quickly exchanges heat with the surrounding rocks.After the hydration reaction begins,the rockfill continuously absorbs heat from the SCC.Approximately 48 hours later,it reaches a temperature peak,and the temperature fields of the two materials approach a homogeneous distribution.The homogeneous RFC model was generated considering the structures of the precast concrete block formworks on the upstream and downstream surfaces,as well as the upstream SCC impermeable layer.The FEM numerical simulations were then conducted by considering equivalent parameters,including the equivalent placement temperature,weighted thermal conductivity,and equivalent adiabatic temperature rise.This model accurately simulated the equivalent homogeneous thermal field during the hydration and temperature decline process.Overall,the arch dam,with its relatively thin profile and rapid heat dissipation,exhibits a low measured hydration rise(only approximately 6℃in winter)owing to the RFC damming material.This strongly supports the feasibility of the construction technology for integrally-poured RFC arch dams.
作者
徐小蓉
余舜尧
金峰
梁婷
罗键
XU Xiaorong;YU Shunyao;JIN Feng;LIANG Ting;LUO Jian(School of Water Resources and Hydropower Engineering,North China Electric Power University,Beijing 102206,China;Astronautics Times Feihong Technology Company Limited,Beijing 100094,China;State Key Laboratory of Hydroscience and Engineering,Tsinghua University,Beijing 100084,China;Yalong River Hydropower Development Company Limited,Chengdu 610051,China;Zunyi Survey and Design Institute of Water Conservancy and Hydropower Co.Ltd,Zunyi 563002,China)
出处
《水利学报》
EI
CSCD
北大核心
2023年第12期1404-1414,共11页
Journal of Hydraulic Engineering
基金
国家自然科学基金重点项目(52039005)
清华大学水沙科学与水利水电工程国家重点实验室开放基金项目(sklhse-2022-C-03)
中央高校基本科研业务专项(2023MS071)。
关键词
堆石混凝土
整体浇筑拱坝
非均质材料
热传导
温度仿真计算
rock-filled concrete
integrally-poured arch dam
heterogeneous material
thermal conduction
temperature field simulation
作者简介
徐小蓉(1990-),讲师,硕士生导师,主要从事大坝温度仿真、颗粒介质力学研究。E-mail:xxrong@ncepu.edu.cn;通信作者:金峰(1966-),教授,博士生导师,主要从事堆石混凝土技术、高坝抗震等研究。E-mail:jinfeng@tsinghua.edu.cn。
