Sampling and Testing Loess Soils
Sampling and Testing Loess Soils
(OP)
I am trying to evaluate the collapse potential due to wetting of soils in the southeast California desert. I am currently planning a geotech. investigation for a lined canal and am looking for advice on how to sample and test the soils.
Some of the areas are in sand dunes so I am thinking the soils will be very easily disturbed and therefore difficult to determine the collapse potential. The more clayey soils could likely be sampled with short pushes of a shelby tube, but the silty and sandy soils will be more difficult to obtain an undisturbed sample. I plan to run single and double odometer tests once I obtain the samples.
Any experience out there on sampling the sandy and silty loess, or on other means of insitu evaluation of collapse potential, possibly from CPT testing?
Thanks
Some of the areas are in sand dunes so I am thinking the soils will be very easily disturbed and therefore difficult to determine the collapse potential. The more clayey soils could likely be sampled with short pushes of a shelby tube, but the silty and sandy soils will be more difficult to obtain an undisturbed sample. I plan to run single and double odometer tests once I obtain the samples.
Any experience out there on sampling the sandy and silty loess, or on other means of insitu evaluation of collapse potential, possibly from CPT testing?
Thanks





RE: Sampling and Testing Loess Soils
Here's an easy field test procedure I used on one of the Orange County toll road projects (tie-in between SR 91 and the east toll road at Bee Canyon):
Dig a trench and stair-step one end so that you can run nuclear densities every 2 feet of depth. After you complete the densities, observe the backfill and measure the size of the depression. At Bee Canyon, we dug a 15 ft trench and were left with a 6 ft depression - a 40% loss of volume without the influence of water!
Please see FAQ731-376 for great suggestions on how to make the best use of Eng-Tips Fora. See FAQ158-922 for recommendations regarding the question, "How Do You Evaluate Fill Settlement Beneath Structures?"