喷射混凝土早龄期徐变的试验研究及预测

EXPERIMENTAL RESEARCH AND PREDICTION ON SHOTCRETE CREEP AT EARLY AGE

  • 摘要: 为了掌握隧道初期支护喷射混凝土的早龄期徐变性能,以地铁和公路隧道最为常用的两种配合比的喷射混凝土为研究对象,模拟施工环境,对喷射混凝土的早龄期徐变性能进行试验研究,完成了不同龄期试件的强度、收缩和受压应变测试,分析了早龄期喷射混凝土徐变特点。将试验值与B3模型和GL2000模型预测值进行比较后,分析了造成试验值与模型预测值之间存在较大偏差的主要原因,有针对性的对GL2000模型的关键项进行了修正,提出了适合于早龄期喷射混凝土徐变度的预测模型。

     

    Abstract: In order to grasp the creep performance of the early-age shotcrete used for the primary lining of a tunnel, creep experiments have been carried out with two different concrete mixes that are mostly used in tunnels of subway and highway respectively by simulating a typical construction environment. The strengths, shrinkage strains and compressive strains of specimens loaded at different ages are measured and the behavior of shotcrete creep at early age is investigated. The comparison between experiment results and predictive values of GL2000 and B3 are made and the main reasons for deviations between the experimental values and predictive values are analyzed. Finally, the pertinent modifications of the key parts of GL2000 are done and a new prediction model of shotcrete creep at early age is proposed.

     

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