Experimental Study on the Impact of Filter Layer Permeability on Revetment Stability Under Wave Action

Abstract

In the design of revetment engineering under wave action, to resist the wave action, the pattern of Top layer - Filter layer – Core(subsoil) is often adopted. In general, the structure of top layer is usually single discrete blocks, typically accropode blocks, four-leg square hollow blocks and barrier boards, and also acropode, riprap, paved rock blocks or concrete slabs where with smaller waves. Such top layer has been provided with many research findings on its stability and is widely used in engineering. Setting a filter layer between the top layer and the lower dike core mainly has two functions: (1) giving certain permeability, to minimize the hydrodynamic load directly acting on the lower foundation soil; (2) giving certain hydraulic tightness, to prevent fine sediment of the lower foundation soil being rushed out. This paper is focused on a special filter layer with geotextile as its upper structure and coarse aggregate as its lower structure. By simulating geotextile with different permeability and coarse aggregate with different size, The pressure of top of cover layer and the down side of the geotextile is tested under wave actions, and compared with theoretical analysis, in this way, how the permeability of geotextile impacts the stability of top layer is studyed. The research shows that when the lower coarse aggregate under the geotextile has high permeability and the geotextile's permeability get poorer, the uplift force to the top layer will be increased under wave action, which will cause damage to the top layer when it si greater than the vertical component force of the block gravity under the water.