基于混凝土软化理论的灌孔砌体受压本构关系研究

Research on constitutive relationship of grouted masonry in compression based on concrete softening theory

文章通过文献对比与试验验证,提出普遍存在于灌孔砌体内的工字受力单元,以混凝土受压软化理论为基础,推导出适用于具有该种受力单元的灌孔砌体受压应力-应变本构关系,表达式考虑了孔洞率、砌块与灌芯混凝土的强度比及软化系数的影响。计算结果表明:文中提出的公式对文献资料与试验实测的峰值点都给出了较为准确的预测,切线模量的退化较好地反映了与灌孔砌体受力破坏过程中的3个阶段,计算曲线与实测曲线契合程度较高。试验现象表明:以工字受力单元为基础构造的受压试件出现与文献资料记录类似裂缝开展规律和破坏特征,试验中观察到明显的三阶段破坏过程;工字受力单元具有较高的合理性,文中公式预测结果与文献资料及试验数据吻合良好,对具有相同内部结构的灌孔砌体有比较高的适用性。

Based on the literature comparison and experimental verification,it is found that the I-shaped mechanical unit commonly exists in grouted masonry.In this paper,a compressive stress-strain constitutive relationship based on concrete softened theory is proposed,which is applicable to the grouted masonry with I-shaped internal structure.In the expression,hollow ratio of masonry,strength ratio of block and grouted concrete,softening coefficient are taken into account.Calculation results show that the peak point is very close to that in documentary records and verification test results.The degradation of tangent modulus agrees well with the three stages in the process of failure,and the calculated curve is in good accordance with the measured one.The test phenomenon shows that the crack development and failure characteristics of specimens with I-shaped mechanical unit are similar to those recorded in the literature,i.e.three stage failure process during the test.I-shaped mechanical unit is reasonable and the prediction result is in good agreement with the literature and experimental data.Therefore,the theory has high applicability to the grouted masonry with I-shaped internal structure.