砌体剪压复合强度的试验研究

Experimental Investigation of Masonry Shear Strength Under Compression

为避免现有砌体结构剪压复合作用下较为繁琐的双向控制强度测试模式,采用一种以单向加载替代传统双向加载的改进试验装置,借助试件角度旋转获取了不同应力比下砌体剪切滑移破坏、受拉破坏、受压破坏3种破坏形态;通过数值分析对试验现象进行对比验证,揭示了不同剪压复合应力状态下砌体抗剪强度的破坏规律;以0.2和0.6为界限采用三段式剪压相关曲线构建出不同应力条件下剪压复合强度破坏准则,以0.2为界限提出了砌体剪压复合受力状态下材料应力应变关系.结果表明:改进试验方法简捷高效误差小,理论计算与试验结果之比的均值为1.07,变异系数为0.180;试验结果丰富了砌体材料本构关系,可为砌体结构破坏准则的完善与数值分析模型的构建提供理论依据.

To avoid the relatively cumbersome strength-testing methods for the existing masonry structures under the combined action of shear and compression,an improved test device substituting uniaxial loading for biaxial is provided to test masonry shear-compression strength under different stress ratios by means of angular rotation of specimen.Comparing the experimental phenomena and numerical analysis results,sliding failure,tensile failure and compression failure of masonry are presented and the failure criterion of shear-compression strength under different stress conditions is established by means of the three-stage shear compression correlation curve with turning points of 0.2 and 0.6,and the stress-strain relationship with turning points of 0.2 under the shear-compression state is proposed.Results show that the improved testing method is simple,efficient and small in error.The mean value of the ratio of theoretical calculation to test result is 1.07,and the coefficient of variation is 0.180.The testing results enrich the constitutive relationship of masonry material,which can provide a theoretical basis for the improvement of masonry failure criterion and the construction of numerical analysis model.