Sand-asphalt : Cohesion and Friction Angle

[AjaxBE]

Hi everyone,

I am working on an oil-storage tank. The bottom of the tanks was protected against corrosion (underneath the bottom plate of the tank, between bottom plate and soil foundation) with 5cm thickness of mixed sand-asphalt layer. The problem is there was a local rupture of the sand-asphalt along the circumference of the tank causing the high edge settlement (or Deflection).

I would like to model this in LimitState:GEO but I don't know what are the properties for mix sand-asphalt (Cohesion and friction angle). Could anyone help me for this one?

Thanks.

 

[Ron]

First of all, the "rupture" of the asphalt did not likely cause the settlement. The settlement was likely caused by something else, probably one or more soil strata beneath the tank.

Second, a sand-asphalt mix has rheological properties that you will not find in soil materials alone. It's strength and stability are functions of the mix characteristics and temperature. Sand-asphalt mixes can range from being a semi-solid to a viscous liquid, depending on temperature. In most instances it will be somewhere between and will deform based on loading.

If I were analyzing the settlement of the tank, I would ignore the asphalt contribution and start the analysis at the bottom of the asphalt, not at the top of the asphalt.