注芯混凝土砌块砌体各向异性强度变化规律试验研究

与普通混凝土材料相比,混凝土砌块砌体由于构成材料的性质迥异、规则性布置方式以及块体自身具有的各向差别而表现出明显的各向异性。本文在宏观层次上,将各组成相材料的影响视为整体的平均表观性能,把具有实际尺寸大小的宏单元体作为基本研究对象,采用唯象方法,进行宏单元体在平面应力状态下强度试验,利用各向异性破坏准则和坐标转换公式把注芯砌块砌体平面应力状态的强度和方向性联系起来,对砌体材料各向强度作了初步探讨。从结果可以看出,主应力沿与材料主轴成20°~70°左右作用的单轴抗压强度比与材料主轴重合情况降低近40%,这种强度的差异随两主应力大小的接近而逐渐减小,当双轴等压时强度几乎不受主应力与材料主轴夹角变化的影响而趋于常值。

Experimental study of anisotropic strength characteristics of grouted concrete block masonry

Compared with plain concrete material, concrete block masonry exhibits distinct directional characteristics on account of the different properties of the anisotropy of the block, its component materials and the regular topology pattern. In this paper, the effect of any component is not distinguished and is treated as a whole. By the phenomenological approach, test on the macro-element with macroscopic dimension was conducted for different principal stress ratios under in-plain loading. By the classical anisotropic failure criteria and coordinates transformation, the laws have been achieved by expressing them in terms of principal stresses and orientation of principal stress to material axis. The strength of uniaxial compression inclined to the material axis 20°- 70° reduce nearly to 60% of the strength with coincidence of principal stress direction and material axis. The difference gradually diminishes with the two stresses closing to each other. And the orientation of principal stress to material axis has little influence on the compressive strength when the two stresses approach equality.