Physical Model for Sintered Gypsum—Clay End-Bearing Piles in Sand

This paper examines the scopes for using soft clay and sintered gypsum in end-bearing earthen piles (EPs). Clay is stabilised with 5–20 wt.% sintered gypsum at three sintering temperatures (0, 600, and 1100 °C) and two curing periods (7 and 28 days). Stabilised clay samples are reconstituted at dry unit weights of 15.0 and 17.5 kN/m3 and subjected to physiomechanical tests, followed by a programme of physical modelling of EPs in sand using a shake table. Under dynamic conditions, excess pore water pressure in sand can create breakaway gaps beneath foundations, causing periodic water movement and foundation rotation. For shallow foundations and earthen piles (EPs), rotation dampens cyclic energy but increases settlement, particularly under light structures. Heavier structures experience reduced rotation due to higher contact pressures, leading to lower settlements. Under static conditions, EPs experience limited settlement as they gain lateral support through sand densification. While rapid densification may induce negative skin friction, it does not significantly affect EP capacity due to their end-bearing nature.