双缝混凝土三点弯曲梁断裂性能试验
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摘要
为了研究双缝混凝土三点弯曲梁的断裂性能,分别对初始缝高比为0.4的单缝,主缝缝高比为0.4、次缝缝高比为0.2～0.4及主次缝间距为120 mm和160 mm的双缝标准混凝土三点弯曲梁,共24个试件进行了试验研究。基于双K断裂理论,分析了次缝缝高比及主次缝间距对实测的荷载-裂缝张口位移P-δ曲线的影响。结果表明:随着次缝缝高比的增大,试件的起裂荷载从4.65 kN增至7.12 kN,增大53.1%,最大荷载从7.37 kN增至8.22 kN,增大11.5%;随着主次缝间距的增大,试件的起裂荷载、最大荷载及其比值均同步先增大后减小,且当主次缝间距为80 mm时,均达到最大。相比单缝试件,次缝缝高比越大,实测P-δ曲线线性段的斜率越高,主次缝间距越大,P-δ曲线线性段的斜率越小。
To obtain the fracture properties of three-point bending concrete beam with double cracks, 24 specimens were tested in this paper. The initial crack-depth ratio of the specimens with a single crack is 0.4. For the specimens with double cracks, the initial crack-depth ratio of the main crack(MC) is 0.4 and it is 0.2～0.4 for the secondary crack(SC), while the distances between the SC and MC are 120 mm and 160 mm, respectively. Based on the double-K fracture theory, the effect of the crack-depth ratio of SC and the distance between SC and MC on the initial load, the maximum load, and the P-δ curve were studied. The results indicate that, with the increase of the crack-depth ratio of the SC from 0 to 0.4, the initial load of the specimens increased from 4.65 kN to 7.12 kN by 53.1%, and the maximum load increased from 7.37 kN to 8.22 kN by 11.5%. With the increase of the distance between SC and MC, the initiation load, the maximum load and the ratio of initial load to maximum load increased at first and then decreased. Meanwhile, values of them reached to the peaks when the distance was 80 mm. Compared to single crack specimens, the bigger the ratio of the SC, the larger the slope of the linear segment of measured P-δ curve; the larger the distance between SC and MC, the smaller the slope of linear segment.
To obtain the fracture properties of three-point bending concrete beam with double cracks, 24 specimens were tested in this paper. The initial crack-depth ratio of the specimens with a single crack is 0.4. For the specimens with double cracks, the initial crack-depth ratio of the main crack(MC) is 0.4 and it is 0.2～0.4 for the secondary crack(SC), while the distances between the SC and MC are 120 mm and 160 mm, respectively. Based on the double-K fracture theory, the effect of the crack-depth ratio of SC and the distance between SC and MC on the initial load, the maximum load, and the P-δ curve were studied. The results indicate that, with the increase of the crack-depth ratio of the SC from 0 to 0.4, the initial load of the specimens increased from 4.65 kN to 7.12 kN by 53.1%, and the maximum load increased from 7.37 kN to 8.22 kN by 11.5%. With the increase of the distance between SC and MC, the initiation load, the maximum load and the ratio of initial load to maximum load increased at first and then decreased. Meanwhile, values of them reached to the peaks when the distance was 80 mm. Compared to single crack specimens, the bigger the ratio of the SC, the larger the slope of the linear segment of measured P-δ curve; the larger the distance between SC and MC, the smaller the slope of linear segment.
引文
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[9]王璀瑾,董伟,王强,等.混凝土Ⅰ型裂缝扩展准则比较研究[J].工程力学,2016,33(5):89-96.(WANG Cuijin,DONGWei,WANG Qiang,et al.A comparative strudy on propagation crition of concrete modeⅠcrack[J].Engineering Mechanics,2016,33(5):89-96.(in Chinese))
[10]徐晓良,杨树桐.钢筋混凝土少筋梁断裂特性试验研究[J].工程力学,2017,34(增刊1):239-243.(XU Xiaoliang,YANGShutong.Experimental study on fracture behavior of lightly reinforced concrete beam[J].Engineering Mechanics,2017,34(Sup1):239-243.(in Chinese))
[11]徐世烺,熊松波,李贺东,等.混凝土断裂参数厚度尺寸效应的定量表征与机理分析[J].土木工程学报,2017,50(5):57-71.(XU Shilang,XIONG Songbo,LI Hedong,et al.Quantitative characterization and mechanism analysis on thicknessdependent size effect of concrete fracture[J].China Civil Engineering Journal,2017,50(5):57-71.(in Chinese))
[12]KACHANOV M.A simple technique of stress analysis in elastic solids with many cracks[J].International Journal of Fracture,1985,28(1):R11-R19.
[13]LI Y P,THAM L G,WANG Y H,et al.A modified Kachanov method for analysis of solids with multiple cracks[J].Engineering Fracture Mechanics,2003,70(9):1115-1129.
[14]SWARTZ S E,LU L W,TANG L D.Mixed-mode fracture toughness testing of concrete beams in three-point bending[J].Materials&Structures,1988,21(1):33-40.
[15]ZHANG Chuanchuan,YANG Xinhua,GAO Hu,et al.Heterogeneous fracture simulation of three-point bending plain-concrete beam with double notches[J].Acta Mechanica Solida Sinica,2016,29(3):232-244.
[16]徐世烺,周厚贵,高洪波,等.各种级配大坝混凝土双K断裂参数试验研究:兼对《水工混凝土断裂试验规程》制定的建议[J].土木工程学报,2006,39(11):50-62.(XU Shilang,ZHOU Hougui,GAO Hongbo,et al.An experimental study on double-K fracture parameters of concrete for dam construction with various grading aggregates[J].China Civil Engineering Journal,2006,39(11):50-62.(in Chinese))
[17]李晓东,董伟,吴智敏,等.小尺寸混凝土试件双K断裂参数试验研究[J].工程力学,2010,27(2):166-171.(LI Xiaodong,DONG Wei,WU Zhimin,et al.Experimental investigation on double-K fracture parameters for small size specimens of concrete[J].Engineering Mechanics,2010,27(2):166-171.(in Chinese))
[18]SWARTZ S E,REFAI T M E.Influence of size effects on opening mode fracture parameters for precracked concrete beams in bending[M].New York:Springer,1989:242-254.
[19]HU Xiaozhi,GUAN Junfeng,WANG Yusuo,et al.Comparison of boundary and size effect models based on new developments[J].Engineering Fracture Mechanics,2017,175(15):146-167.
[20]XU Shilang,REINHARDT H W.Determination of double-determination of double-K criterion for crack propagation in quasibrittle fracture Part I:experimental investigation of crack propagation[J].International Journal of Fracture,1999,98(2):111-149.
[2]章佺,许念增,龚安特.混凝土坝坝墩的断裂力学分析[J].工业建筑,1979,9(1):42-48.(ZHANG Quan,XU Nianzeng,GONG Ante.Fracture mechanics analysis of concrete dam pier[J].Industrial Construction,1979,9(1):42-48.(in Chinese))
[3]潘家铮.断裂力学在水工结构设计中的应用[J].水利学报,1980,11(1):47-61.(PAN Jiazheng.Application of fracture mechanics to the design of hydraulic structures[J].Journal of Hydraulic Engineering,1980,11(1):47-61.(in Chinese))
[4]于骁中,居襄.混凝土断裂韧性的研究[J].力学与实践,1980,2(4):69-71.(YU Xiaozhong,JU Rang.Research on fracture toughness of concrete[J].Mechanics in Engineering,1980,2(4):69-71.(in Chinese))
[5]徐世烺,赵国藩.混凝土结构裂缝扩展的双K断裂准则[J].土木工程学报,1992,25(2):32-38.(XU Shilang,ZHAOGuofan.A double-K fracture criterion for the crack propagation in concrete structures[J].China Civil Engineering Journal,1992,25(2):32-38.(in Chinese))
[6]XU Shilang,REINHARDT H W.Determination of double-K criterion for crack propagation in quasi-brittle fracture,Part II:Analytical evaluating and practical measuring methods for three-point bending notched beams[J].International Journal of Fracture,1999,98(2):151-177.
[7]中华人民共和国国家发展和改革委员会.水工混凝土断裂试验规程:DL/T 5332-2005[S].北京:中国电力出版社,2006.
[8]胡少伟,范向前,陆俊.强度等级对混凝土双K断裂参数的影响[J].水电能源科学,2012(9):77-81.(HU Shaowei,FANXiangqian,LU Jun.Influence of strength grade on double-K fracture parameters of concrete[J].Water Resources and Power,2012(9):77-81.(in Chinese))
[9]王璀瑾,董伟,王强,等.混凝土Ⅰ型裂缝扩展准则比较研究[J].工程力学,2016,33(5):89-96.(WANG Cuijin,DONGWei,WANG Qiang,et al.A comparative strudy on propagation crition of concrete modeⅠcrack[J].Engineering Mechanics,2016,33(5):89-96.(in Chinese))
[10]徐晓良,杨树桐.钢筋混凝土少筋梁断裂特性试验研究[J].工程力学,2017,34(增刊1):239-243.(XU Xiaoliang,YANGShutong.Experimental study on fracture behavior of lightly reinforced concrete beam[J].Engineering Mechanics,2017,34(Sup1):239-243.(in Chinese))
[11]徐世烺,熊松波,李贺东,等.混凝土断裂参数厚度尺寸效应的定量表征与机理分析[J].土木工程学报,2017,50(5):57-71.(XU Shilang,XIONG Songbo,LI Hedong,et al.Quantitative characterization and mechanism analysis on thicknessdependent size effect of concrete fracture[J].China Civil Engineering Journal,2017,50(5):57-71.(in Chinese))
[12]KACHANOV M.A simple technique of stress analysis in elastic solids with many cracks[J].International Journal of Fracture,1985,28(1):R11-R19.
[13]LI Y P,THAM L G,WANG Y H,et al.A modified Kachanov method for analysis of solids with multiple cracks[J].Engineering Fracture Mechanics,2003,70(9):1115-1129.
[14]SWARTZ S E,LU L W,TANG L D.Mixed-mode fracture toughness testing of concrete beams in three-point bending[J].Materials&Structures,1988,21(1):33-40.
[15]ZHANG Chuanchuan,YANG Xinhua,GAO Hu,et al.Heterogeneous fracture simulation of three-point bending plain-concrete beam with double notches[J].Acta Mechanica Solida Sinica,2016,29(3):232-244.
[16]徐世烺,周厚贵,高洪波,等.各种级配大坝混凝土双K断裂参数试验研究:兼对《水工混凝土断裂试验规程》制定的建议[J].土木工程学报,2006,39(11):50-62.(XU Shilang,ZHOU Hougui,GAO Hongbo,et al.An experimental study on double-K fracture parameters of concrete for dam construction with various grading aggregates[J].China Civil Engineering Journal,2006,39(11):50-62.(in Chinese))
[17]李晓东,董伟,吴智敏,等.小尺寸混凝土试件双K断裂参数试验研究[J].工程力学,2010,27(2):166-171.(LI Xiaodong,DONG Wei,WU Zhimin,et al.Experimental investigation on double-K fracture parameters for small size specimens of concrete[J].Engineering Mechanics,2010,27(2):166-171.(in Chinese))
[18]SWARTZ S E,REFAI T M E.Influence of size effects on opening mode fracture parameters for precracked concrete beams in bending[M].New York:Springer,1989:242-254.
[19]HU Xiaozhi,GUAN Junfeng,WANG Yusuo,et al.Comparison of boundary and size effect models based on new developments[J].Engineering Fracture Mechanics,2017,175(15):146-167.
[20]XU Shilang,REINHARDT H W.Determination of double-determination of double-K criterion for crack propagation in quasibrittle fracture Part I:experimental investigation of crack propagation[J].International Journal of Fracture,1999,98(2):111-149.
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