Numerical Analysis of Seepage Failure Modes of Sandy Soils within a Cylindrical Cofferdam

Soil seepage failure within cofferdams is a dangerous phenomenon that always poses difficulties for designers and builders of excavations in zones with high water levels. When the hydraulic head difference H between upstream downstream sides reaches critical height, soil occurs. Depending on properties, soil-wall interface characteristics, cofferdam design, different modes can be observed: heaving, boiling, liquefaction, or by reduction passive earth pressure. In literature, there are differences, sometimes very large, value loss Hc/D inducing given several methods proposed stability verification. Then, complex cases generally approached using simplifying assumptions adopting large safety factors to take account uncertainties. practice, geotechnical engineers deal many kinds shapes cofferdams, such as rectangular, square, circular, which generate three-dimensional (3D) flow conditions. Axisymmetric through circular often used model 3D flow. this paper, numerical code FLAC, simulations carried out axisymmetric groundwater conditions analyze cohesionless sandy soils cylindrical cofferdam. The effects radius, internal friction, dilatancy, friction mode studied. numerically obtained presented discussed various scenarios. present results, illustrated both tables graphs, show significant decrease Hc/Dinducing failure, radius. They also indicate sensitivity As well, new terms designations based view deformation. Doi: 10.28991/CEJ-2022-08-07-06 Full Text: PDF