莫尔-库仑准则的单位化及其在棱柱体测混凝土抗压强度中的应用

Unitization Transformation of Mohr-Coulomb Criterion and Its Application to Prism Concrete Test Blocks Subjected to Compression

以混凝土抗压强度测试中棱柱体的破裂形态为切入点,分析了端面强约束边界条件下棱柱体的破裂面倾角,并基于单位化后的莫尔-库仑准则,借助于混凝土强度试验数据,反算了不同等级混凝土剪切破坏时真实的破裂角范围和最危险破裂角。结果表明:3倍高宽比是最危险破裂面不受边界条件影响的临界值;边界条件通过改变破裂路径影响了强度,破裂路径的改变才是产生形状效应的根本原因;不同高宽比时其破裂面不同,考虑边界条件对破裂路径的影响时,可以建立强度形状效应的解析式。

On the basis of the fracture morphology of the prism in the test of concrete compressive strength,the azimuth of fracture surface of the prism subjected to uniaxial compression was analyzed when the boundary conditions of prism end face were strongly constrained,and then the fracture angle range and the most dangerous rupture angles were studied by means of laboratory tests and the unitization transformation of classical Mohr-Coulomb criterion.The results show that:The 3:1 height-width aspect ratio is the critical value as the most dangerous fracture surface is not affected by the boundary conditions;The boundary condition influences the strength through changing the fracture path,and the passive migration of the rupture path is the root cause of the shape effect;The fracture surface is different with different height width ratio,so the analytical formula of the strength shape effect can be established when considering the influence of boundary conditions on the crack path.