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利用SPAX-2000(改进型)静动真三轴系统,针对淤泥类超软土进行静动力排水固结试验,研究包括较高频率在内的各冲击荷载频率(1、8、16 Hz)与不同围压(200、250、300 k Pa)作用下淤泥的力学响应;此外,结合三轴剪切试验研究不同固结条件对淤泥不排水强度的影响。试验结果表明:(1)在相同冲击频率作用下,试样抗剪强度随着围压增大而提高;围压增大,使得球应力增大,体应变随着增大,有效地促进试样排水固结。(2)相同围压作用下,存在着一个冲击荷载频率阈值,当冲击频率低于这一阈值时,随着冲击荷载频率的提高,轴向应变量逐渐变小,反之逐渐变大。(3)冲击瞬间,体应变为负值,表现为体胀,这与原位试验夯击瞬间的孔隙水压力变化曲线一致,从而验证了高含水率淤泥在冲击作用下的孔压负增长现象。
Based on the static and dynamic triaxial system of SPAX-2000 (improved), the static and dynamic drainage and consolidation tests of silt super soft soil are carried out to study the effect of each impact load frequency (1,8,16 Hz) The mechanical response of silt under different confining pressures (200, 250 and 300 kPa) was studied. In addition, the influence of different consolidation conditions on the undrained strength of silt was studied by triaxial shear tests. The experimental results show that: (1) Under the same impact frequency, the shear strength of the specimen increases with the increase of confining pressure; as the confining pressure increases, the ball stress increases and the volume strain increases with the increase of the confining pressure. Drainage consolidation. (2) Under the same confining pressure, there is an impact load frequency threshold. When the impact frequency is lower than this threshold, the axial strain becomes smaller as the impact load frequency increases, otherwise it becomes larger. (3) At the moment of impact, the body strain becomes negative, which manifests itself as body bulge. This is consistent with the curve of pore water pressure at the instant of tamping in situ test, which verifies the negative growth of pore pressure under the impact of high water content sludge.