66_CEG 4012 Notes Fall 2011 CEG 4012 Notes Fall 2011

66_CEG 4012 Notes Fall 2011 CEG 4012 Notes Fall 2011 - much...

Info iconThis preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
Wire rope or light chaiD Locking pin Overshot Foil chambers Holding ring ""----". .-- Groove and wedges (or rasteDina of steel (oils Sampling Brass liner Sampling r-"t-_JUl. . tube Spcar--i-0 head Thbe (a) X7 to break sample at bottom before removal. Leading edge usually sharpened and slightly pressed inward for side relief «1%). Although the tubing is thin and easily damaged the area ratio is a little high (10-15%). Sample may be extruded or cut out. Common sizes: 2" 00 w/0.049" wall (18 gage), 3" 00 w/O.065" wall (16 gage), 5" 00 w/0.120" wall (11 gage), lengths 36"-54". Tubes are coated to inhibit corrosion, may be stainless also. o Piston Samplers are inserted closed (piston at mouth of sampler) down to borehole bottom and then the sampler is pushed around the piston into the soil. Piston may fixed (held in place) during the push, floating (allowed to free float), or be held in place by a fixed pressure. Piston helps minimize expansion disturbance, but too
Background image of page 1
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: much load on piston may compress sample during push. These samplers can be very expensive & complicated (e.g. foil sampler). Shelby tube modifications sometimes include a piston. Can get very high quality samples (e.g. Osterberg sampler). (Figure from Bowles, 1996) u.rFiud piston Thin-walled sampling tube Beainoina operation Thin-walled Top piston is (ully advanced and sample (e) tube can be recovered Typic:aI pl~ton ~plers. ~a) Sta~onary piston sampler for recovery of "undisturbed" samples of . . cohesive SOI~. Piston rcmams stationary on soil and tube is pushed into the soil; piston is then clamped and sample IS recovered; (b) Swedish foil sampler; (e) Osterberg piston sampler. (Hl'onlev (/949))....
View Full Document

{[ snackBarMessage ]}

Ask a homework question - tutors are online