不同冲击频率与中主应力下细砂力学响应研究

使用SPAX-2000改进型真三轴试验系统对饱和细砂进行循环冲击动力固结试验，研究不同固结条件、不同冲击荷载作用频率与不同中主应力作用下细砂应力-应变关系等力学响应；并结合三轴剪切试验，分析对比了不同条件下冲击荷载作用后试样强度的变化特征。试验结果表明：中主应力增大，试样在冲击荷载的作用下更容易趋于密实，抗剪强度得到较大的提高；频率降低，在中主应力较小时动力固结后试样抗剪强度有明显的提高，而在中主应力较大时试样抗剪强度没有太大变化；表明了中主应力和冲击荷载频率是影响试样动力固结效果的重要因素。

Mechanical Responses of Fine Sand under Different Impact Loading Frequencies and Intermediate Principal Stresses

We carried out cyclic impact and consolidation tests with different intermediate principal stresses on saturated fine sand by using improved SPAX-2000 true triaxial testing system,and investigated the mechanical responses of the sand such as stress-strain relations and strength variation of specimen after the impact loading under different conditions.Results showed that: when intermediate principal stress increased,the specimen under impact loading was easily tend to be dense,and shear strength was largely improved;when the frequency of impact load was lower and the intermediate principal stress smaller,shear strength of the specimen increased significantly,while when the second principal stress was larger,shear strength of the specimen rarely varied.The results indicate that intermediate principal stress and frequency of impact load are important factors affecting the dynamic consolidation.