C.9 Rock bit types and sizes

See Figures C.11 and C.12 and Tables C.18 and C.19.

Figure C.11 — Three-cone milled tooth rock bit	Figure C.12 — Tungsten carbide button bit

C.10 Examples of core lifter and sample retainer design

Core lifters are used to break off the core sample at the end of a coring run and then to retain the sample within the corebarrel for return to the surface. Figure C.13 shows a few of the more common types used.

C.10.1 Typical corebarrel lifters

a) Plain	d) Internal slotted with basket fingers
b) Internal slotted	e) Internal slotted and serrated with basket fingers
c) Internal slotted and serrated

C.10.2 Typical samplerretainers

Sample retainers are used to retain the soilsample within the sampling tube as the sample tube is withdrawn to the surface. Figure C.14 shows a few examples of the most popular.

a) Basket retainer of plastic or steel	c) Basket retainer (heavy duty)
b) Spring retainer (light duty)	d) Flap valve

C.11 Sampling equipment

C.11.1 Thin wall sampler (Shelby tube)

See Figure C.15.

Key

• 1 sampler head with drill rod box connection
• 2 air relief port
• 3 grub screws (3) secure sample tube to head
• 4 thin wall Shelby tube
• 5 chamfered cutting edge

C.11.2 Hydraulic piston sampler

See Figure C.16.

Key

• 1 drill rod pin
• 2 1/4" BSP hose connection
• 3 outer conductor tube
• 4 inner conductor tube
• 5 oil port A
• 6 inner piston
• 7 oil port B
• 8 hydraulic cylinder (5 litre)
• 9 grub screw for securing sample tube
• 10 black plate with allen-cap screw
• 11 piston seal
• 12 piston head
• 13 aluminium sample tube

C.11.3 Stationary piston sampler

Figure C.17 shows a stationary piston sampler with a 50-mm diameter liner for taking samples in soft to stiff cohesive soils and silts (sampling category A).

a) sampler before punching	b) after releasing the lock;alternative with shutter	c) when pushing is finished and rod is released

Key

• 1 lock
• 2 brake
• 3 spring
• 4 plunger
• 5 ball
• 6 hardened ring
• 7 vent
• 8 wedges
• 9 springs
• 10 set screw
• 11 piston rod
• 12 sample tube
• 13 outer cylinder
• 14 cutting edge
• 15 release rod
• ^a To be adjusted based on the material.

Figure C.18 shows the different parts of a stationary piston sampler with a 50-mm liner.

A stationary piston sampler with a linerof 50 mm diameter for taking samples in soft to stiffcohesive soils and silts (sampling category A and B) is shown in Figure C.19. The samples are cut by rotating the inner rod system. This sampling principle is also used for taking samples in cohesionless soils with liners of 25 mm , 34 mm and 50 mm diameter (sampling category B).

C.11.4 U100 Sampler

See Figure C.20.

A) Standard system	B) Plastic liner system

Key

C.11.5 Standard penetration test (SPT) samplers

See Figure C.21.

Key

• 1 SPT rod
• 2 Top adaptor
• 3 Split spoon sampler
• 4 SPT shoe
• 5 SPT solid cone
• 6 SPT assembly complete
• 7 SPT solid rod

C.11.6 Typical automatic trip hammer

See Figure C.22.

Key

• 1 lifting eye
• 2 outer tube
• 3 lifting pawls with springs
• 4 drive weight
• 5 guide rod
• 6 anvil

C.11.7 Window and windowless samplers

Figure C.23 shows a window sampler for taking samples in cohesionless soils (sampling category C). The window is opened by rotating the rod system.

a) Window sampler	b) Window sampler with 35 mm and 50 mm diameter	c) Windowless sampler	d) Driving rod

Key

• 1 sample tube-window
• 2 shoe
• 3 sample tube
• 4 plastic liner
• 5 retainer