粗粒土渗透及渗透变形试验缩尺方法研究

Scale method for coarse soil seepage and seepage stability test

目前还未建立适用于粗粒土渗透及渗透变形试验的缩尺方法,遵循缩尺前后粒径小于d30(颗粒级配中质量百分含量30%所对应的颗粒粒径)以及粒径小于5 mm的颗粒含量及组成不变的原则,基于等量替代法,提出了一种粗粒土渗透及渗透变形试验缩尺方法:如果原级配中5 mm以下的颗粒含量大于等于30%,则根据试样允许最大粒径以下的大于5 mm的各粒组含量,按比例等质量替换超粒径颗粒;如果原级配中5 mm以下的颗粒含量小于30%,则根据试样允许最大粒径以下的大于d30的各粒组含量,按比例等质量替换超粒径颗粒。利用多组粗粒土渗透及渗透变形试验,论证了缩尺方法的可靠性。研究表明:提出的缩尺方法合理可行。缩尺后,土体渗透破坏型式未发生变化,渗透系数与原级配比较接近,渗透变形临界坡降和破坏坡降与原级配基本一致,缩尺级配的渗透及渗透稳定特性能够较好地反映原级配的渗透及渗透稳定特性。

At present,there is no suitable scale method for seepage and seepage stability test of coarse soil.Based on the equivalent alternative method,a new scale method for seepage and seepage stability test was proposed by keeping the particles finer than d30(the grain size corresponding to 30%finer in particle size distribution)and particles finer than 5 mm unchanged.If the particle content finer than 5 mm in the original particle size distribution is larger than or equal to 30%,the oversized particles are replaced by the particles ranging from the largest allowable particle of specimen and particles larger than 5 mm;if the particle content finer than 5 mm in the original particle size distribution is less than 30%,the oversized particles are replaced by the particles ranging from the largest allowable particle of specimen and particles larger than d30.A list of seepage and seepage stability tests on coarse soils was carried out to verify the proposed scale method.The results indicate that the proposed scale method is suitable and effective.The seepage failure mode does not change after scaling,the permeability of the coarse soils after scaling is also close to that of the original soils,and the critical hydraulic gradient and failure gradient of seepage instability are basically consistent with the original soils.Consequently,the seepage and seepage stability characteristics of the coarse soils after scaling can represent the original coarse soils.