Experimental study of failure mode and mechanism of stable gentle soil slope triggered by small mass of gas and water

Abstract The combination of small mass of pressurized gas and water is a strong external triggering factor for landslides, but the corresponding failure mechanism and failure mode of the landslide are less studied. This paper presents a laboratory model experiment to investigate the landslide triggered by the combination of pressurized gas and water in a gentle soil slope. The triggering is achieved by the injection of H 2 O 2 solution into the dry cement powder core covered by an impermeable layer in the slope. The injected H 2 O 2 can be decomposed into small mass of gas (0.23% of slope soil mass) and water (1.16% of slope soil mass). The test results show the overall failure mode of the gentle slope in the test is upheaval-penetration-rupture-settlement-slide. The soil upheaval and pressurized fluid mixture penetration are unique feature behaviors of the landslide triggered by the pressurized gas and water. The pressurized gas triggered by impenetrable soil layer can increase the active sliding force and decrease the resistance by reducing the normal effective stress. The penetration of the fluid mixture through the interface between sliding soil and sliding base can further reduce the sliding resistance. In addition, mechanical models are established to perform dynamic analysis of the soil upheaval and slide. A calibration test for the decomposition of H 2 O 2 in cement powder is further carried out to verify the generated gas can give enough pressure for the mechanical model.