三轴冲击荷载作用下淤泥剪切性状的试验研究

Experimental Study of Shear Characters of Mucky Soils under Triaxial Impact Loading

使用SPAX-2000(改进型)静动真三轴,研究淤泥类超软土在较高冲击荷载频率(16Hz)等不同频率与不同围压下的剪切性状。研究表明:(1)静动力排水固结法可对深层软土起到加固作用,且效果更加明显(经过不同冲击频率作用的抗剪强度分别比原抗剪强度大29%、25%、36%);(2)在较高的中主应力下,试样均出现了应变软化现象,且其早期剪切强度都高于常规三轴的试件,有可能每一个固结比都对应一个最佳的冲击频率,并且在最佳频率的作用下,试件可以在Kc固结状态下通过静动力排水固结加固作用而不发生应变软化现象。

The shear strength characters of mucky excessive soft soils were studied by using an improved true triaxial device SPAX-200 under different a relative high impulse frequency（16Hz）with various confining pressures.The conclusions are presented in this paper：both the static and dynamic consolidation methods could have an obvious result of improving the soil shear strength.The results indicate that the soil samples with various impulse stress could have strength increase of 29%,25% and36%,respectively;2）the strain softening effect was observed with intermediate or high confining pressures and the shear strength at the initial stage is higher than the samples under the conventional triaxial confining pressure.An optimum impulse frequency might exist for each sample under each over-consolidation ratio.Under this optimum impulse frequency,shear strength of the soil samples that under the same over-consolidation ratio can be improved throughout the dynamic and static consolidation action without strain softening effect.