Type of Soil UD Samplers

[struggle67]

Hi Everyone,

Good Morning

I am new to geotechnical engineering.

My SI company told me that they won't take any UD for hard soil as their equipment hydraulic pressure is not high enough and their normal Shelby thin wall sampler is not suitable for hard soil. They also didn't use the cleaning bucket to clean the base, they said water pressure is aldy good enough to clean base before taking the sample. Is that a problem?

My understanding of samplers

(1) Shelby thin wall sampler - Suitable for soft soil and use hammering or hydraulic pressure to push sampler into the soil.
(2) Thin wall piston sampler - Suitable for soft soil and hydraulic pressure to push sampler into the soil. can get better samples compared to normal thin wall samplers due to the suction developed.
(3) Rotary sampler - Suitable for hard soil but do we still use the same equipment used for drilling to rotate the cutting bit?
(4) Mazier sampler - Same as a rotary sampler?

Do you guys usually do lab tests on hard soil? Will it be too much if I insist my SI contractor to do it?

Thanks

 

[GeoEnvGuy]

If by "hard" you are referring to a material that has a unconfined compressive strength of > 400 KPA or undrained shear strength of > 200 KPA, than it is not typical to test this as soil. It is typical to diamond core this material and test it as a low strength concrete.

 

[geomane]

Research pitcher sampler or Denison sampler

 

[struggle67]

Thanks, Guys

GeoEnvGuy

If by "hard" you are referring

"by hard" SI company was referring to soil with SPT > 30 blows which should correspond to undrained shear strength about 150 kPa.

Thanks