Heave Failure as a Fourth Type of Seepage-Induced Internal Instability Problems Associated With Granular Soils

Internal instability problems associated with granular soils involves washing out of the fine grains within the voids of the coarse grains. This movement may involve one or more of the following, mass loss, volume change, and permeability change. Leading to the occurrence of one of these possible cases, namely, suffusion (involves mass loss with no volume change), suffusion (involves mass lose with volume reduction), fluidization (involves volume change without mass loss). These three cases are well defined in the literatures; however the authors of this paper have found a fourth case (heave failure) was not taken in consideration. Heave failure involves both mass lose and increment in volume of the granular soil. Deep understanding of this case will prevent failure of geotechnical and hydraulic structures. Here in this paper the conditions that lead to the occurrence of heave failure are defined and illustration is made based on some experimental studies. Also it is found that the applied stresses on the soil can change the mode of internal instability failure from suffusion to suffusion / suffusion failure mode. editor