| 摘要: |
| 为研究空洞缺陷对混凝土楔入劈拉性能的影响，将空洞缺陷等效为相应纵向截面高度的损失量，并推导了含空洞缺陷混凝土楔入劈拉断裂参数的计算式，同时利用改进型测试装置进行了8组共32个试件的楔入劈拉性能试验，分析研究了空洞尺寸及其位置变化对试件楔入劈拉性能的影响规律。结果表明，起裂荷载、失稳荷载、起裂张口位移和失稳张口位移都随着空洞尺寸增大（直径0~120 mm）而降低，降幅分别为43.59%，23.75%，39.85%，54.50%；空洞缺陷对混凝土的起裂韧度影响较小，但却会明显降低混凝土失稳韧度，随着空洞尺寸增大，其降幅达到46.20%；空洞位置对混凝土断裂特性的影响跟裂纹扩展路径相关，当裂纹经过空洞时会降低相关参数，当其远离空洞区域时，则影响较小。 |
| 关键词: 楔入劈拉 空洞缺陷 混凝土断裂 性能分析 |
| DOI： |
| 分类号:TV331;TU317.1 |
| 基金项目:国家杰出青年科学基金资助项目(51325904)；水利部公益性行业科研专项经费项目(201501036) |
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| Experimental studies and performance analysis of wedge splitting for concrete specimens with cavity defects |
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HU Shaowei,HU Xin
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1.Nanjing Hydraulic Research Institute, Nanjing;2.College of Water Conservancy and Hydropower Engineering, Hohai University, Nanjing
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| Abstract: |
| In order to investigate the defects such as the cavity influences on the wedge splitting performance of the concrete, the cavity is made equal to a loss of the height of the longitudinal section and the calculation formulas for the wedge splitting fracture parameters of the concrete with cavity defects are derived. And then 8 groups including 32 specimens are designed for the wedge splitting tests using the improved testing instrument developed by our team. The influences of different sizes and locations of the cavity on the wedge splitting performance of the concrete are analyzed. The test and calculation results show that along with the increases of the cavity size (diameters from 0 to 120 mm), initial load, instability load, initial CMOD (crack mouth opening displacement) and instability CMOD are respectively reduced by 43.59%, 23.75%, 39.85% and 54.50%. The cavity defects have smaller effects upon the initial toughness of the concrete as their values are stable, but the cavity defects have greater effects on the instability toughness of the concrete, and the instability toughness decreases by 46.20% with a increase in the cavity size. The influences of the cavity location on the wedge splitting performance are relevant to a crack propagation path. When the crack passes through the cavity, the related fracture parameters are reduced; when the crack is far away from the cavity, it has a little effect. |
| Key words: wedge splitting cavity defect concrete fracture performance analysis |
