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(北京工業(yè)大學(xué)城市減災(zāi)與防災(zāi)防護(hù)教育部重點(diǎn)實(shí)驗(yàn)室， 北京 100124)

［摘要］應(yīng)變率效應(yīng)和尺寸效應(yīng)是混凝土力學(xué)領(lǐng)域重要的基礎(chǔ)科學(xué)問(wèn)題。以強(qiáng)度為代表的力學(xué)性能指標(biāo)隨應(yīng)變率增大而提高、隨結(jié)構(gòu)尺寸增大則存在劣化的趨勢(shì)。目前，對(duì)應(yīng)變率效應(yīng)的研究多采用試驗(yàn)觀測(cè)的經(jīng)驗(yàn)方法，現(xiàn)有表征應(yīng)變率效應(yīng)強(qiáng)弱的動(dòng)力增大因子計(jì)算模型多基于有限數(shù)據(jù)擬合，參數(shù)缺少物理意義，因此不利于工程實(shí)際應(yīng)用；尺寸效應(yīng)方面已存在幾類(lèi)基于不同理論框架的模型分析方法，但仍存在較大分歧。結(jié)合前期研究工作中建立的具有實(shí)際物理意義參數(shù)的混凝土抗拉強(qiáng)度動(dòng)力增大因子計(jì)算模型和考慮混凝土材料配合比參數(shù)的全局尺寸效應(yīng)模型，提出了同時(shí)考慮應(yīng)變率效應(yīng)與尺寸效應(yīng)影響的普通混凝土名義抗拉強(qiáng)度理論預(yù)測(cè)方法。研究可為基于性能的大體積混凝土配合比設(shè)計(jì)方法及其動(dòng)態(tài)強(qiáng)度預(yù)測(cè)方法提供理論依據(jù)。 

［關(guān)鍵詞］混凝土；應(yīng)變率效應(yīng)；尺寸效應(yīng)；動(dòng)態(tài)強(qiáng)度；動(dòng)力增大因子 

中圖分類(lèi)號(hào)：TU398-7 文獻(xiàn)標(biāo)識(shí)碼：A文章編號(hào)：1002-848X(2021)17-0122-07

Theoretical prediction method for nominal tensile strength of ordinary concrete considering strain rate effect and size effect 

LI  Dong,  DU  Xiuli,  JIN  Liu 

(Key Laboratory of Urban Security and Disaster Engineering of Ministry of Education, Beijing University of Technology, Beijing 100124， China) 

Abstract: Strain rate effect and size effect are important basic scientific problems in the field of concrete mechanics. The mechanical properties represented by strength increase with the increase of strain rate and deteriorate with the increase of structure size. At present, the empirical method of experimental observation is mostly used to study the strain rate effect. The existing calculation models of dynamic increase factor, which represents the degree of strain rate effect, is mostly based on the fitting of limited data, and the parameters lack physical significance. Therefore, it is not conducive to the practical application of engineering. Several types of model analysis methods have been established based on different theoretical frameworks in terms of size effect, however, large differences are apparent. Based on the calculation model of concrete tensile dynamic increase factor with parameters of actual physical significance and the global size effect model considering the design parameters of concrete mix proportion in the previous work, theoretical prediction method for nominal tensile strength of ordinary concrete considering both strain rate effect and size effect was proposed. The research can provide theoretical basis for performance-based mix proportion design method and dynamic strength prediction method of mass concrete. 

Keywords:concrete； strain rate effect； size effect； dynamic strength； dynamic increase factor

*國(guó)家重點(diǎn)研發(fā)計(jì)劃專(zhuān)項(xiàng)（2018YFC1504302）。

 作者簡(jiǎn)介：李冬，博士，研究員，博士生導(dǎo)師，Email: dong.li@bjut.edu.cn；通信作者：杜修力，博士，教授，博士生導(dǎo)師，Email: duxiuli@bjut.edu.cn。