Speeding up the consolidation process Speeding up the consolidation process jjsim (Civil/Environmental) (OP) 31 Oct 17 01:05 Looking at ways to quicken up the consolidation process of a 20ha land overlain with very soft clay and sand layers with SPN less than 10. Any novel ideas? I know the conventional way is adding surcharge and installing vertical drains. Any faster way? RE: Speeding up the consolidation process Okiryu (Civil/Environmental) 31 Oct 17 08:13 Not a novel method but it is not commonly done: http://www.ad-hzm.co.jp/trr/hazama/2006/pdf_file/0... RE: Speeding up the consolidation process EireChch (Geotechnical) 31 Oct 17 08:55 there is a reason surcharge and installing vertical drains is the conventional way. Its probably the best, most economical way... RE: Speeding up the consolidation process fattdad (Geotechnical) 31 Oct 17 16:13 If you can accurately depict the sand layers you may find you don't even need the vertical drains! Jam a piezo cone in the ground and see what you can clearly define. Then I'd calculate the magnitude of consolidation and figure out what U% I'd need to mitigate the problem. Calculate the time for that U% and see whether you need a surcharge? f-d ípapß gordo ainÆt no madre flaca! RE: Speeding up the consolidation process oldestguy (Geotechnical) 1 Nov 17 23:49 I'd run a test fill. You might surprise yourself as compared to running lab consolidation tests. In my experience most recent surcharge jobs take only 1 month max and some only a week per location with a rolling surcharge. These are 10 ft high with 10 ft wide windrow suface. RE: Speeding up the consolidation process JHeisenberg (Geotechnical) 3 Nov 17 16:21 As you already know, surcharge and drains would be the most common method. Much more expensive but we have used soil mixing techniques to mitigate large settlements when we did not have time to wait for the drains and surcharge to do their thing. RE: Speeding up the consolidation process HENRYZAU (Geotechnical) 5 Nov 17 00:15 JJ, I would suggest you do CPTu tests and take a few good quality samples for 1-D consolidation tests to have a better understanding of the permeability and yield stress, compressibility. Depending on the outcome and the expected final stress level, you may or may not need surcharge or wicks or both. If test results suggested low Ch and high Cc/1+e0 and low yield stree, and soft clay is thick then both wicks and surcharge is required. If time is the primary concern, and the owner is willing to spend extra to buy time, think about lime column or concrete injection column (CIC). Good luck Henry RE: Speeding up the consolidation process fattdad (Geotechnical) 6 Nov 17 13:09 Just recall that Cv is usually about 2 to 4 times lower than Ch. If there are PVDs the time for consolidation is informed by Ch. You will not get Ch from a consolidation test. f-d ípapß gordo ainÆt no madre flaca! RE: Speeding up the consolidation process HENRYZAU (Geotechnical) 6 Nov 17 21:06 Fattdad, CPTu dissipation test will give a reasonable estimate of Ch. Agree that Cv from oedometer test could be a few times lower than that in the field. RE: Speeding up the consolidation process fattdad (Geotechnical) 7 Nov 17 12:31 Yes, Henryzau. That was the intent of my first post. f-d ípapß gordo ainÆt no madre flaca! RE: Speeding up the consolidation process jjsim (Civil/Environmental) (OP) 16 Nov 17 11:11 JHeisenberg, what are the soil mixing techniques? Examples? RE: Speeding up the consolidation process Okiryu (Civil/Environmental) 16 Nov 17 14:37 We use deep soil mixing as typical soil improvement method..