sampler,open drive sampler, piston sampler, rotary sampler

sampler,open drive sampler, piston sampler, rotary sampler
vedio link
https://youtu.be/MoXp98jFodc

1. TawiEngineering College
TOPIC-TYPES OFSAMPLERS
FoundationEngineering
Presented
by
Sanjeev singh
Part -6

2. Three types of sampler.
1.Open drive
sampler
2.Pistonsampler
3.Rotarysampler

3. Undisturbed samples are obtained from boreholes by opendrive
samplers.
Opendrivesamplersconsistofthinwalledtubeswhichare
pushedordrivenintothesoilatthebottomoftheholeandthen
rotateddetachthelowerendofthesamplefromthesoil.
Most soft or moderately stiff cohesive soil can be sampled
without extensive disturbance in thin walled seamless steel
tubes having diameter not less than 50mm.
The lower end of the tube is sharpened to form a cutting edge and
the other end is machined for attachment to the drillrods.
The entire tube is pushed or driven in to the soil at the bottom of
the hole and is removed sample withinside.
The two ends of the tube are then sealed and sample shifted to
the laboratory.

5. Inside
diameter,
mm
38 70 100
Outside
diameter, mm
40 74 106
Minimum
effective length,
cm
30 45 45

6. Piston sampler consists of twoparts-
SamplerCylinder
Pistonsystem
The piston fits tightly in the samplercylinder.
Good quality undisturbed samples are obtained from
pistonsamplers which use thin –walled sampling tubes
with a pistoninside.
Thetubeisbeingloweredtothebottomofthedrillhole,
thepistonrodsandpistonareheldatthebottomofthe
samplerbymeansofadrillrodwhichrisestothetopofthe
borehole.
Thepresenceofthepistonpreventsexcesssoilfrom
squeezingintothetubeandthus,maintainstheintegrity
ofthesample.

8. A Rotary Sampler is a double –walled tube sampler withan
inner removableliner.
The outer tube or the outerbarrel is provided with a cutting bit.
Theouter barrel isrotates and cut into the soil.
The inner tube which is stationary, slides over the cylindrical
sample cut by the outer rotating barrel. The sample is collected
in the innerliner.
Rotary samples are useful for sampling in firm to hard cohesive
soils and particularly in rocks