关键词: 粗粒土, 渗透变形试验, 缩尺方法, 渗透稳定

Abstract:

A series of scaling methods for oversize particles in geotechnical test of coarse-grained soil are proposed based on equivalence of dry density, shear strength, deformation and permeability, however the treatment to oversize particle in seepage stability test is not clear. Various scaling methods were used to perform seepage deformation tests on gap-graded coarse-grained soils with different seepage stabilities. As a comparison to these treated materials test results, some original-gradation materials tests were also carried out in order to analyze the applicability of different scaling methods to seepage stability test. The test results illustrate that for the gap-graded soil with gap-graded size below 5 mm the seepage failure type and hydraulic condition of piping or flowing type soil treated by the equivalent alternative method is the same as original-gradation materials, because of unchanged pore volume of skeleton and filling degree of fines. The similar grading method would make a proportional decrease to soil particle as well as characteristic particle size D20 that reflects pore size of coarse particle, thus resulting in piping type soils transformed to transition failure. The similar grading method would not change flowing type soils′ seepage failure type, but can reduce the critical damage gradient due to increase of soil discrete level. The equivalent alternative method can get better scaling effect than the similar grading method.

Key words: coarse-grained soil, seepage deformation test, scale method, seepage stability