疏浚砂混凝土的压剪性能和破坏准则的试验研究

Experiments of compression-shear performance and failure criterion of dredged sand concrete

以长江下游疏浚砂为原材料,制备了4种不同疏浚砂掺量的混凝土试件,对疏浚砂混凝土试件的压剪复合性能进行研究。1)进行了5种不同轴压比下的压剪复合试验。试验结果表明:疏浚砂混凝土的压剪界面摩擦系数在疏浚砂含量较高时会下降,而试件内部黏聚力则随疏浚砂含量的增加而增加;同时试件压剪峰值位移随疏浚砂含量的增加呈现先增大后减小的趋势。2)对试件破坏界面进行SEM形貌分析,研究疏浚砂影响试件性能的微观机制。3)结合试验结果和已有文献研究,提出了基于八面体空间应力和基于Ottosen模型的破坏准则,并给出了准则方程中的拟合参数。试验数据与拟合结果吻合程度良好。

This paper selected dredged sand from the lower reaches of the Yangtze River as raw material and prepared four concrete specimens with different dredged sand contents to study the compression-shear performance of the concrete specimens.1)The paper carried out compression-shear tests under five different axial pressure ratios,and the test results show that the friction coefficient of the compression-shear interface of dredged sand concrete decreases when the dredged sand content is high,while the internal cohesion of the specimens increases as the dredged sand content improves.In addition,the peak value of the compression-shear displacement of the specimens increases first and then decreases as the dredged sand content rises.2)The paper analyzed the morphology of the damaged interface of the specimens through a scanning electron microscope(SEM)and studied the micro-mechanism of the dredged sand affecting the specimen performance.3)According to test results and existing literature,the paper proposed a failure criterion based on the octahedral spatial stress and the Ottosen model and presented fitting parameters for the criterion equation.Furthermore,the experimental data are in good agreement with the fitting results.