These should be collected as drilling or digs proceed, where possible attempting to preserve the in situ water content; disturbed samples are mainly required for soil identification and for classification and quality test; or tin, or plastic bags
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| Split spoon sampler |
2. Undisturbed samples
In which the structure and water content is preserved, as far as possible, to truly represent site conditions; undisturbed samples are required for test of shear strength, consolidation and permeability; these are usually obtained by a suitable coring method
3. ROCK CORING
When a rock layer is encountered during a drilling operation, rock coring may be necessary. To core rocks, a core barrel is attached to a drilling rod. A coring bit is attached to the bottom of the barrel (Figure ). The cutting elements may be diamond, tungsten, carbide and so on. The coring is advanced by rotary drilling. Water is circulated through the drilling rod during coring, and the cutting is washed out.
