Core Sampling in all kind of Soil
Soil Sampling
The purpose of geotechnical studies and field investigations is to determine the properties of soil to identify its behavior. This is determined based on the results of borehole drilling, field tests, and laboratory tests. Therefore, soil samples must be obtained and sent to the laboratory for testing. An important point in soil sampling is that the desired sample must represent the actual conditions of the soil at the site. Therefore, the sampler characteristics, sampling method, and storage and handling of the sample are very important.
Based on compatibility with field conditions, sample types can be divided into two categories:
- Disturbed sample
- Undisturbed sample
Disturbed Sample
In a disturbed sample, the field structure, void ratio, and moisture content of the soil change, but the particle sizes remain intact. Tests that can be performed on disturbed samples include Atterberg Limits, shrinkage limit, and particle size distribution. For granular soils, obtaining an undisturbed sample is very difficult. Therefore, the sample is compacted to the field density. This type of sample is called a remolded sample. It should also be noted that remolded samples cannot be prepared for cemented granular soils, as it destroys the cementation.
Figures 1 to 3 show disturbed samples obtained by Baran Khak va Pey Engineering Consultants.
Figure 1: Disturbed sample packaging by Baran Khak va Pey Engineering Consultants.
Figure 2: Disturbed sample packaging by Baran Khak va Pey Engineering Consultants.
Figure 3: Disturbed sample packaging by Baran Khak va Pey Engineering Consultants.
The storage method for disturbed samples depends on project requirements. If required, the moisture content is maintained by wrapping the sample in foil. Figures 4 to 8 show some disturbed soil samples obtained and packaged by Baran Khak va Pey Engineering Consultants
Figure 4: Disturbed sample packaging by Baran Khak va Pey Engineering Consultants.
Figure 5: Disturbed sample packaging by Baran Khak va Pey Engineering Consultants.
Figure 6: Disturbed sample packaging by Baran Khak va Pey Engineering Consultants.
Figure 7: Extracting sample from sampler by Baran Khak va Pey Engineering Consultants.
Figure 8: Sampling using double Core Barrel by Baran Khak va Pey Engineering Consultants.
Undisturbed Sample
In an undisturbed sample, all soil parameters are identical to the in-situ conditions for testing purposes.
Thin wall tube or Shelby tube samplers obtain undisturbed samples, with small ratios of outer to inner diameters, pushed into the soil.
Figures 9 to 13 show the Shelby tube sampling process used by Baran Khak va Pey Engineering Consultants. After sampling, the ends are sealed with wax to retain moisture and isolate the sample. Information including project name, borehole, depth, top, bottom, and other details are attached. The sample is carefully placed in a PVC liner, capped at both ends, with a duplicate information tag, for protected transportation to the laboratory.
Figure 9: Sealed Shelby tube sample by Baran Khak va Pey Engineering Consultants.
Figure 10: Sealed Shelby tube sample by Baran Khak va Pey Engineering Consultants.
Figure 11: Sealed Shelby tube sample by Baran Khak va Pey Engineering Consultants.
Figure 12: Sealed Shelby tube sample by Baran Khak va Pey Engineering Consultants.
Figure 13: Shelby tube sample encapsulated in PVC liner, ready for laboratory transportation, by Baran Khak va Pey Engineering Consultants.