Pile tip failure for mini-ICP during penetration in NE34 sand in calibration chamber. (a) Tip stresses q_b measured by Yang et al. (2010) plotted against penetration depth S, compared with predictions from ALE FE modelling with crushable grain model by Zhang et al. (2013). (b) Failure system and particle breakage zoning observed by Yang et al. (2010). (c) Particle breakage pattern predicted around tip by Zhang et al. (2013)