Centrifuge model study on settlement of strip footing subject to rising water table in loess

Abstract

Owing to man-made activities and natural conditions, the groundwater table experiences considerable changes in Lanzhou. Centrifugal model tests were performed to investigate the settlement of strip footings on loess subject to rising water table under different foundation pressures. The air-fall method was employed to reconstitute the artificial loess samples. The applicability of the air-fall prepared samples was evaluated against the parameters of the undisturbed loess samples obtained from the same location. The results of centrifuge tests reveal that the footing settlement increases significantly with increasing foundation loading pressure or increasing rising water table. However, the rate of increase in ultimate footing settlement under combined rising water level and footing pressure is established to be more intriguing. A simplified method for predicting the ultimate footing settlement on collapsible loess due to rising water table height is proposed. The proposed formulation is verified, as there is a good agreement between the test results under various loading pressures and rising water heights and the predicted ultimate footing settlements. A discussion on the ultimate settlement of strip footings subjected to rising water table against conventional bearing capacity safety factors is presented to provide some basis for the foundation design consideration under rising water scenario.