Experimental and numerical study on the size effect of miniature penetration strength in fluidized solidified soils

To investigate the influence of probe size on the miniature penetration strength ([Formula: see text]) of fluidized solidified soil, miniature penetration tests were conducted on fluidized solidified soil specimens with varying probe diameters ([Formula: see text]) and stabilizer contents ([Formula: see text]). The micro-mechanism of the size effect was subsequently revealed through DEM simulations, leading to the proposal of a [Formula: see text] prediction formula incorporating the size effect. Experimental results demonstrate that [Formula: see text] decreases rapidly at first and then more gradually as [Formula: see text] increases. This [Formula: see text]-dependency of [Formula: see text] is more significant in lower-strength specimens. For instance, the [Formula: see text] ratio between the 2mm and 5mm probes was 1.43 for specimens with [Formula: see text]=3% but only 1.28 for specimens with [Formula: see text]=18%. DEM simulations suggest that the normal stress acting on the probe tip is the primary component of [Formula: see text] and is nearly independent of [Formula: see text]. Conversely, the frictional force on the probe lateral surface, which is proportional to [Formula: see text], is identified as the source of the size effect. Furthermore, the zones of stress disturbance and cementation breakage induced by probe penetration extend approximately 0.5 [Formula: see text] from the probe shaft. Regardless of the stabilizer contents, the penetration stress can be predicted using an inverse proportional function with respect to [Formula: see text].