干湿冻融循环对土体渗透系数的影响研究

Study on the Influence of Dry-wet and Freeze-thaw Cycles on Soil Permeability Coefficients

以青海湖区域典型粉土为研究对象,基于室内干湿循环、冻融循环及渗透试验,研究干湿、冻融循环对粉土渗透系数的影响规律,并利用有限元软件MIDAS/GTS分析不同渗透系数对路基沉降的影响规律。研究结果表明,干湿循环与冻融循环均会导致土体渗透系数增大,其中干湿循环对增大土体渗透系数的作用更大;经历5次干湿循环和冻融循环后,干湿循环和冻融循环对土体渗透系数的影响已较小,渗透系数趋于稳定;土体渗透系数越大,越有利于土中孔隙水的排出,增加土体的瞬时沉降,有利于加速超孔隙水压力的消散,减小地基的工后固结沉降,但不会改变地基总的沉降。

Based on the indoor dry-wet cycles,freeze-thaw cycles and infiltration tests,the influence law of dry-wet and freeze-thaw cycles on the infiltration coefficient of silt is studied with the typical silt in Qinghai Lake area,and the influence law of different infiltration coefficients on the settlement of roadbed is analyzed with the finite element software MIDAS/GTS.The research results show that both dry-wet cycles and freeze-thaw cycles will lead to the increase of soil permeability coefficient,among which the dry-wet cycles have a greater effect on the increase of soil permeability coefficient.After five dry-wet cycles and freeze-thaw cycles,the effect of dry-wet cycles and freeze-thaw cycles on soil permeability coefficient has been smaller,and the permeability coefficient tends to be stable.The larger the soil permeability coefficient is,the more it is conducive to the discharge of pore water in the soil,accelerating the transient settlement of the soil,accelerating the dissipation of pore excess water pressure,reducing the post-work consolidation settlement of the foundation,but it will not change the total settlement of the foundation.