Dealing with subsidence due to groundwater overpumping

[genomty]

I'm dealing with a site located within a zone that is experimenting subsidence phenomenon, the subsidence ratio is about 1.5 inches per year. This movements are the result of an excesive extraction of ground water, it has been estimated that inflow defficit is about 239 millions of cubic meters per year. In consecuence, groundwater level has dropped about 110 meters during the past 50 years. Seismic movements of about 3.4 degrees in the Richter scale have been measured nearby the cracks when soils are settling. Nearest cracks to the site are located to abuot 150 meters.

Subsurface conditions consist of a layer of sany soils mixed with construction debris having a thickness of about 3 feet, followed by stiff to very stiff clays until about 17 feet. The alluvial deposits have a thicknes of about 1000 feet. I know that flexible foundations should be preferred over rigid foundations.

So, may questiion for this this scenario is:

Is there any guidelines, codes or recommendations to be followed to prepare a geotechnical recommendation in a situation like the above described?

 

[VAD]

Your best bet is to review Leonardo Zeevaert's text- Foundation Engineering For Difficult Subsoil Conditions. He did a lot of work re foundations in Mexico City which underwent significant subsidence due to well pumping. This may be a start, as well as there may be others on the forum who have been involved with this problem that may offer advice as well.

Regards

 

[BigH]

As well, read anything you can about Bangkok. Similar to that of Mexico City. Asian institute of Technology. Prof. Bergado.

 

[cvg]

subsidence is a problem in this area also due to the same reason. Some of the problems we experience are:

1) fissures - the latest opened up a couple of months ago during heavy rains and is 8 miles long and up to 25 feet deep

2) differential subsidence when you are near a bedrock high point

3) drainage channels reversing course due to differential subsidence

4) uniform subsidence is not so much of a problem