水泥-磷石膏改良泥炭质土动力特性研究

Dynamic Characteristics of Cement-Phosphogypsum Improving Peaty Soil

为了研究水泥-磷石膏的综合改良对昆明滇池地区泥炭质土动力特性的影响效果,基于前期已有的室内试验成果,对掺入不同含量水泥和磷石膏的改良泥炭质土进行室内动三轴试验,重点研究了其动力响应和强度特性在不同围压、加载频率、掺量、固结比、动应力幅值条件下所受的影响,分析了N=6振级下的滞回曲线变化规律以及XRD测试结果。研究表明,经改良后的泥炭质土动力特性有极大的变化。在仅掺入水泥作为主改良剂的基础上,刚度和弹性得到一些提升。之后加入磷石膏作为外加剂,二者综合作用下的提升效果更加明显,抗变形能力显著提升,土体能量消散能力降低,滞回曲线有明显向纵坐标轴偏转的趋势。由此说明相较于水泥的单一作用,水泥-磷石膏的复合作用对改良泥炭质土的土体刚度和弹性有着更加显著的提升作用,极大地提升了抗震性能,改良后的泥炭质土可以更好地应用于相关的实际工程。

In order to study the effect of cement-phosphogypsum comprehensive improvement on the dynamic characteristics of peaty soil in Dianchi area of Kunming,the laboratory dynamic triaxial test of improved peaty soil with different content of cement and phosphogypsum was carried out based on the previous laboratory test results.The effects of dynamic response and strength characteristics under different confining pressures,loading frequencies,dosages,consolidation ratios and dynamic stress amplitudes were mainly studied.The hysteresis curve change law at N=6 vibration level and the results of XRD test were analyzed.The results show that the dynamic characteristics of improved peaty soil change greatly.On the basis of separately adding cement as the main modifier,the stiffness and elasticity have been slightly improved.After adding phosphogypsum as an admixture,the combined effect is more obvious,the deformation resistance is improved significantly,the energy dissipation ability of soil is reduced,and the hysteresis curve has an obvious tendency to deflect to the longitudinal axis,which indicates that compared to the single action of cement,the composite action of cement-phosphogypsum has a more significant improvement effect on the soil stiffness and elasticity of the improved peaty soil,greatly improving the seismic performance.The improved peaty soil can be better applied to relevant practical engineering.