Soluble Soils - (Gypsum Dissolution & settlement)

[farqy]

Hi,

I am aiding a collegue with the analysis of settlement caused by gypsum dissolution in granular soils.

We are currently in the early stages of our workings.

does anyone have any experience of this??

Currently i am looking through 'Soluble materials in civil engineering' by James, but i am unable to find a method which allows the quantification of settlement from voids created from gypsum dissolution. I have got as far as calculating the 'solution front' width, but unsure of where to go from here.

any hints, tips or recommended literature would be greatly appreciated.

Cheers

F

 

[emmgjld]

I know the problem and understand your problem.
I deal with this A LOT and have no good way to quantify the potential or even a good test method. I deal with sandy gravels and cobbles, which is too large for standard testing.

The problem is complicated as I am in an arid to semi-arid environment and the gypsum is actually as a cementing agent within the coarse soils. As the soils moisten, the gypsum will reach a point of yielding and the particles start to move around. I end up with a soil collapse and if water is continually added in sufficient quantities, solution occurs and more settlement occurs. The solution of the gypsum actually is a minor problem, as the structure or road section has already moved and repairs are in process.

You might check out some work done in the Colorado central mountains, in the Eagle, Glenwood Springs, Carbondale and Gypsum Area. The Colorado Geological Survey (

http://geosurvey.state.co.us/

) could probably direct you to some publications. You might try searching for Steve Pawlick as an author. I believe the more practical knowledge has not been published, as we consultants don't have a lot of time for such things.