Hi All,
I am dealing with concrete sleeper design for pipeline crossings. The soil i'm dealing with is really weak, its soft silty clay with very low undrained shear strength of order 1.5kPa. My concrete sleeper whatever size it is, is failing in bearing. I have very limited soil data, to be precise only shear strength of soil at the top surface and one value of 9kPa at the bottom (2.1m). Could I linearly interpolate the strength of soil with depth? My first perspective is, it is not correct. But thats the only way I can make this soil strong enough to bear the structure. I have attempted to provide skirts, but it gives unreasonable depth of skirt required. Any expert advice/suggestions would be greatly appreciated. Thanks in advance.

Cheers,
Uday