AS 1289.1.3.1:2015 pdf download.Methods of testing soils for engineering purposes Method 1.3.1: Sampling and preparation of soils- -Undisturbed samples- -Standard method.
3 APPARATUS
3.1 Sampling apparatus
3.1.1 General
The sampling apparatus to be used will depend upon the soil being sampled and the amount of disturbance permitted in the soil. This method does not define the criteria for the selection of sampler types.
All samplers shall have space into which excess material can pass if the sampler is overdriven or if there is some undetected loose material present. For routine testing of undistributed soils, the following nominal sample tube sizes are preferred: 75 mm diameter. 63 mm diameter. 50 mm diameter. 38 mm diameter.
3.1 .2 General definitions
The proportions of a sampler may be specified by its area ratio, inside clearance, outside clearance (see Figure 1) and internal length.
3.1.3 Open-drive samplers
3.1.3.1 General
An open-drive sampler shall consist of an open-ended tube of sufficient rigidity to enable the tube to be pushed into the soil being sampled. Escape ports to permit escape of water or air shall be fitted to the top of the tube and shall have an area of not less than 25% of the cross-sectional area of the sample. A non-return valve shall be fitted to the escape ports to remove the water load from the top of the sample.
The sampling tube shall be capable of being fitted with a sampler head which will permit the penetration of the sampling tube. The attachment of the sampler head shall be concentric and coaxial to the tube to assure uniform application of the force to the tube by the insertion equipment. The attachment of the sampler head to the sample tube shall also permit the rotation and extraction of the sample tube.
3.1.3.2 Thin-walled sampler
A thin-walled sampler consists of a tube with a bevelled cutting edge machined directly on to the tube. The sampler shall meet the following requirements:
(a) The area ratio shall not exceed 10%.
(b) The cutting edge shall be machined with the bevel on the outer edge of the tube making an angle not exceeding 15° to the axis of the tube with a land not wider than 0.5 mm at the cutting edge. The inside clearance shall not exceed 1% of the diameter at the cutting edge. The internal length of the sample tube shall not exceed 10 sample diameters. The inside of the tube shall be smooth and free from pitting.
3.1 .3.3 Composite samplers
A composite sampler shall consist of a hardened cutting shoe screwed on to the lower end of the sampling tube. The area ratio shall not exceed 25% and the inside clearance shall be not greater than 2% of the diameter at the cutting edge.
3. 1 .4 Piston samplers
This device consists of an open-drive sampler fitted with a piston which slides inside the
sample tube. Two types of piston samplers are normally used as follows:
(a) Stationary type piston sampler—the piston is connected by rods which extend to the surface so that the position of the piston and sampling tube are controlled independently.
(b) Floating type piston sampler—the piston is initially locked to the sampler hut after release the piston floats on the top of the sample.
3.1 .5 Air injection samplers
An air injection sampler is an open-ended sampling tube which is fitted with a small diameter (about 3 mm) hollow tube attached to the outside of the sampler and inserted into the sample tube through a hole about 25 mm from the bottom. The upper end of the attached tube is connected to an air supply at the surface by flexible tubing.
3. 1 .6 Rotary coring samplers
3.1.6.1 General
This consists of a non-rotating tube which is forced into the soil whilst a rotating device on the outside of the tube removes the cuttings as the tube is advanced. The cutting edge of the non-rotating sample tube shall project beyond the rotary cutters and shall be spring loaded so that the shoe retracts as resistance to penetration increases. The spring loading mechanism shall ensure that the cutting edge retracts only as far back as the level of the cutting edges to facilitate the removal of cores, the inner tube may be fitted with a removable liner.
NOTE: The spring-loading mechanism should be sufficiently stiff so that the cutting shoe will not reach the level of the cutting edge until a vertical force equivalent to 75% of the capability of the drilling machine is applied to the sampler.AS 1289.1.3.1 pdf download.