玄武岩-混凝土界面抗剪性能的影响因素及特征分析

Analysis on Effect Factors and Characteristics of Shear Propertiesfor Interfaces Between Basalt and Concrete

为研究玄武岩-混凝土界面抗剪性能的影响因素及特征,设计了一种用于测试该性能的试验装置。采用同一场地的玄武岩和C20、C30混凝土试件,开展30组试件岩-混柱形的界面室内模型剪切试验。根据试验获得的荷载-位移曲线,确定极限抗剪承载力,并计算获得了界面抗剪强度平均值。将试验结果归一化处理后,研究了接触面尺度因素、混凝土设计强度等级和龄期、岩石完整性对界面抗剪性能的影响。试验结果表明:该装置能够有效模拟并试验测试岩石与混凝土界面的抗剪性能;接触面积与模型剪切承载力呈正相关,但与剪切面的高度或直径相关性不大,岩样高度越大则强度试验统计变异系数越小;90%置信概率下,混凝土养护7 d后,混凝土设计强度等级与界面抗剪强度变化不明显;混凝土龄期不大于7 d时其对界面强度有一定的正向影响,龄期增大可降低剪切强度时的极限位移;岩石完整性越好,则岩石与混凝土界面抗剪强度越高。

In order to study effect factors and characteristics of shear properties for interfaces between basalt and concrete,a test device for testing properties was designed.Using basalt and C20 and C30 concrete from the same site,30 indoor specimens for shear tests of rock-concrete interface were conducted.According to the load-displacement curve obtained by the test,the ultimate shear bearing capacity was determined,and the mean value of the interface shear strength was calculated.After normalizing the test results,the effects of interface scales,strength grades and curing ages of concrete,and rock integrity on shear properties of interfaces were studied.The test results showed that the device could effectively simulate and measure the shear properties of interfaces between rock and concrete;the shear capacity of specimens was strongly positive correlative with contact areas,but was not obvious correlative with height or diameter of shear planes.The statistical coefficient of variation for measured strength values increased with the decrease in height of the rock specimens;after the curing age for 7 days,the design strength grade of concrete had an inapparent effect on the interface shear strength under 90%confidence probability;when the curing age of concrete was more than 7 days,the increase in curing age had a positive effect on the interface strength,the longer the curing age of concrete was,the smaller the displacement at the shear strength was.The more intact the rock was,the higher the shear strength of interfaces between rock and concrete was.