渡槽混凝土早期受冻劈裂抗拉声发射特性  

Tensile Acoustic Emission Characteristics of Aqueduct Concrete During Early Freezing Splitting

作　　者：屈春来[1] 高月坤 胡宝文[1,2,3] 李磊 林镕鹏 QU Chun-lai;GAO Yue-kun;HU Bao-wen;LI Lei;LIN Rong-peng(College of Water Conservancy and Hydropower,Hebei University of Engineering,Handan 056038,China;Beijing Key Laboratory of Urban Underground Space Engineering,Beijing 100083,China;Hebei Key Laboratory of Inelligent Water Conservancy,Handan 056038,China)

机构地区：[1]河北工程大学水利水电学院,河北邯郸056038 [2]城市地下空间工程北京市重点实验室,北京100083 [3]河北省智慧水利重点实验室,河北邯郸056038

出　　处：《水电能源科学》2022年第8期153-156,共4页Water Resources and Power

基　　金：河北省高等学校科学技术研究项目(BJ2019023);河北省自然科学基金项目(E2019402256)。

摘　　要：为研究渡槽混凝土早期受冻劈裂抗拉过程的声发射特征,对不同起冻时刻、不同冻结温度的混凝土试块进行劈裂抗拉试验,分析了不同工况下混凝土的劈裂抗拉力学性能,重点研究了混凝土破坏过程中的声发射振铃计数率、累计振铃计数及声发射b值特征,并基于累计振铃计数建立声发射活跃性方程。结果表明,混凝土劈裂抗拉强度损失程度从大到小依次为4.0、1.5、8.0、24.0 h、未冻,劈裂抗拉强度随着冻结温度降低而降低;4.0 h起冻的混凝土加载初期振铃计数率和b值最大,加载全程的累计振铃计数最少,b值峰值最小,受冻结影响最严重;由声发射活跃性方程得出未冻混凝土试件的声发射活跃性最强,此时参数a_(1)的值最小,参数b_(1)的值最大。In order to study the acoustic emission characteristics of the early freezing and splitting tensile process of the aqueduct concrete,the splitting tensile test was carried out on the concrete specimens with different freezing moments and freezing temperatures,and the splitting tensile mechanical properties of the concrete under different working conditions were analyzed.The acoustic emission ringing count rate,cumulative ringing count and acoustic emission b-value characteristics in the process of concrete failure were studied,and the acoustic emission activity equation was established based on the cumulative ringing count.The results show that the degree of splitting tensile strength loss of concrete is 4.0 h,1.5 h,8.0 h,24.0 h,and unfrozen;The splitting tensile strength decreases as the freezing temperature decreases;The ringing count rate and b value are the largest at the initial stage of concrete loading for 4.0 h starting to freeze,the cumulative ringing count during the whole loading process is the smallest,and the b value peak is the smallest,which is the most severely affected by freezing;The acoustic emission activity of the unfrozen concrete specimen was obtained from the acoustic emission activity equation.At this time,the value of parameter a_(1) is the smallest,and the value of parameter b_(1) is the largest.

关 键 词：早期受冻 混凝土 声发射特征 声发射活跃性方程 

分 类 号：TV431[水利工程—水工结构工程]