尾矿砂免烧砖砌体的破裂特征

Fracture characteristics of masonry structure with iron tailing baking-free brick

为了提高尾矿砂的综合利用率,采用自制等级Mu20的铁尾矿砂免烧砖与M5混合砂浆,砌筑了砖砌体并进行了砌体局部抗压加载试验.加载的同时,用非接触视频测量系统实时跟踪测试了受荷至破坏全过程位移场的变化.结果显示:尾矿砂砖砌体的破坏为脆性破坏,其荷载-位移曲线可分四个阶段,即:压密阶段、弹性变形阶段、裂缝稳定扩展阶段以及破坏阶段;尾矿砂砖砌体在局部受压过程中,当荷载小于破坏荷载的80%时,砌体未见宏观裂缝,但试件表面位移场的变化还是比较显著的,且个别点的位移变化与整体的趋势有所不同.在加载后期,试件的位移场数值变化较之前显著加快,且各观测点的位移方向趋同.

To enhance the multipurpose utilization ratio of mine tailings, the brick masonry was constructed with both self-made Mu20 grade iron tailing baking-free brick and M5 mixed mortar, and the loading experiments for the local compression-bearing capacity were conducted. With loading, the variation of displacement field during whole process from load-bearing to destroy was tracked and tested with the non-contact video measuring system. The results show that the fracture of tailings brick masonry is brittle failure, and the corresponding load-displacement curve can be divided into four stages, namely compaction stage, elastic deformation stage, stable crack propagation stage and failure stage. During the local compression-bearing process, no macro cracks are observed in the masonry structure when the load is less than 80% of failure load, while the surface displacement field of specimens significantly changes, and the change tendency of displacement at individual points is different from the overall trend. At the later loading period, the variation of displacement field obviously accelerates, and the displacement direction at each measuring point tends to be similar.