creeping flow of gypsum rock below driven piles

[Utica]

Hello,

I am designing driven piles, without sockets at this stage, 1500 mm in diameter or so, into natural gypsum rock to support a bridge. The project is in salt water environment. Ultimate strength in uniaxial compression is about 20-24 MPa. Is anyone aware of a risk of settlement of the piles by creep flow of the gypsum rock that may occur in response to the applied service loads? Case studies would be appreciated if any. Thank you in advance for your help,

 

[emmgjld]

The stress field in front of the pile toe will probably result in the gypsum flowing away from the toe. I have personally observed this condition, which has resulted in piling settlement of 50 to 200 mm. The condition is maximized if water flow through the gypsum/gyp bearing rock or soil is occurring.