利用静、动三轴试验机对大骨料混凝土预先施加三轴压荷载历史，之后对经历荷载历史的试件进行同应变率的单轴受压试验，研究了大骨料混凝土的动态受压性能与所经历的加载速率(应变率为10-5~10-2 s-1)和应力比荷载历史的关系.所有试验的三轴压荷载历史中σ3均加载至2.8fc ，且未达到材料的极限强度，但是大部分试件已产生了微裂缝和不可恢复的变形.试验表明：在单轴受压试验中，大骨料混凝土破坏会沿着已有的裂缝继续发展，破坏形态不同于单轴抗压的柱状破坏，而与三轴压荷载下的斜剪破坏极为相似.经历三轴压荷载历史后的大骨料混凝土的抗压强度随着侧压力的增加而降低，随着应变率的提高而提高.强度损失随着应变率的增加而减小，随着侧压力的增加而增加.%The experiments of dam concrete under the dynamic uniaxial compression are carried out after the triaxial compression loading history with the same strain rate by static and dynamic triaxial test equipment.The influence of loading history of strain rate (ranging from 1 0-5 to 1 0-2 s-1 )and stress ratio on the dynamic strength of dam concrete is analyzed.Theσ3 in the triaxial compression loading history is up to 2.8fc,and does not achieve the ultimate strength,but there are slight cracks and the unrecoverable deformation on the specimens.The experimental results show that the failure mode of dam concrete continues to develop along the existing cracks under dynamic uniaxial compression,and it is different from the column failure under uniaxial compression,but similar to the skew shear failure under triaxial compression.After triaxial compression loading history,the strength of dam concrete under uniaxial compression decreases with the increase of confined compressive stress,and increases with the increase of strain rate;the strength damage of dam concrete decreases with the increase of strain rate,and increases with the increase of confined compressive stress.
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