Material, preparation, and cycle dependence of pressure behavior in a slowly plunged granular column

Pressure transmission and drag force fluctuation in a slowly plunged granular column are measured with various sample preparations, grains shapes, and cyclic penetration tests. First, we slightly modify the nonlinear scaling laws for drag force and pressure transmission, which have been reported in Katsuragi [2012. Nonlinear wall pressure of a plunged granular column. Phys. Rev. E 85, 021301]. Next, we find that the modified scaling relations are almost independent of details of grains and sample preparations, particularly in vertical direction. By ten times cyclic penetration tests, we reveal that the first penetration is quite particular than other successive ones. After the second penetration, the work to penetrate into the granular column becomes independent of the cycle number. Namely, there are two groups, such as the first penetration and others. From the drag force fluctuation analysis, we find that the fluctuation is almost proportional to the square root of the size ratio between grains and the intruder. ► The relations between slow drag force and transmitted wall pressures are investigated with various grains and preparation methods. ► Cyclic penetration effect is evaluated for the granular penetration. ► Granular drag force fluctuation is related to the effective grains size.