泥石流拦砂坝坝基土颗粒级配对扬压力影响实验研究

颗粒级配是影响坝基渗透的重要因素,并影响扬压力的大小和分布特征。采用自制装置对不同颗粒级配的6种土样进行坝基渗透实验和竖向渗透实验,研究了细颗粒含量和最小粒径对坝基渗透和扬压力分布的影响,并建立了细颗粒含量与坝基渗透系数和扬压力之间的关系。研究结果表明:坝基土细颗粒含量530%P40%时,最不易发生沉降变形和渗透变形;不同颗粒级配下坝基扬压力沿中轴线均呈线性衰减;坝基土发生渗透变形前扬压力折减系数与渗透系数存在对数变化关系,与细颗粒含量呈线性负相关关系,渗透变形后,扬压力出现大幅波动。

Experimental study on the uplift pressure of a check dam with foundation soils of different grain compositions

Grain composition affects the permeability of foundation soils significantly and has considerable impact on the magnitude and distribution of uplift pressure. In order to study the permeability of the foundation soils and the uplift pressure of a check dam，the vertical and horizontal seepage devices were designed and six groups tests were performed on soils of different grain compositions. The relationships between the uplift pressure and the permeability coefficient/fine content of the foundation soils were established. The results show that the foundation soils are most stable when the content of fine particles(＜5 mm) is in the range of . The uplift pressure decreases linearly along the axis of dam base. Besides，the reduction coefficient of uplift pressure has a logarithmic relationship with the permeability coefficient k and has a negative linear correlation with the content of fine particle before the seepage failure. The uplift pressure varies dramatically when the seepage failure occurs.