Visual and Lab Based Soil Classification.pptx

geotechnical Investigation: Visual and Lab Based soil classification according on ASTM 2488-17 & 2487-17

1. Visual & Lab-Based Soil Classification System Sizia Amaral

2. Agenda Introduction Type of Soil Visual Soil Classification Unified Soil Classification System (USCS) Conclusion Questions

3. Introduction A soil classification System It is the arrangement of different soils with similar properties into group and subgroups based on their application or to their probable engineering behavior It provides a common language to briefly express the general characteristic of soils, which are infinitively varied without detailed descriptions.

4. Textural Classification Soil classified based on grain size as: Boulders Cobbles Gravel Sand Silt Clay Trace Particles are Present but estimated to be < 5% Few 5% to 12% Little >12% to <30% Some >30% to <50% Mostly >50%

5. Visual Soil Descriptions (ASTM 2488-17) Soil Description: Color (Red, Brown, Grey, Green, White, Black) Odor (If Organic Soil or Unusual) Moisture Condition (Dry, Moist, Wet) HCl Reaction (Weak, Moderate, Strong) Angularity (Angular, Sub-Angular, Rounded, Sub-rounded) Shape (Flat, Elongate) Consistency (Very Soft, Soft, Firm, Hard & very Hard)

6. Field Soil Descriptions (ASTM 2488-17) Angularity Shape

7. Unified Soil Classification System (ASTM 2487-17) UNIFIED SOIL CLASSIFICATION SYSTEM (USCS) USCS is a Laboratory-based soil classification system for mineral and organic soils that use series of flowchart based on grain size distribution, Liquid Limit and Plastic Index test result. There are two major soil divisions for soil passing the 75 mm sieve: Coarse Grain Soil (Sand, Gravel, Cobble and Boulders) Fine Grain Soil (Silt/Clay)

8. Coarse grain soil Coarse grain soil divided into 2 group: Gravel (G) Sand (S)

9. Fine Grain Soil Fine grain soil have more than 50% or more particles passing a No. 200 sieve or 0.075 mm sieve and are classified according to Atterberg Limit. Based on Casagrande's Plasticity Index distinction is made between soil with LL less than 50% (Symbol L), equal or Greater than 50% (Symbol H), Above the A-Line (Clay symbol C) or below the A-Line (Silt, Symbol M). PI between 4 and 7 above the A-line, and PI less than 4 to clarify the fine-grained soil as five groups: Lean Clay, Silty Clay (CL – ML) Silt (ML), Fat Clay (CH) and Elastic Silt (MH).

10. Fine Grain Soil

11. Conclusion SUMMARY OF UNIFIED SOIL CLASIFICATION SYSTEM (USCS) AND SYMBOLS

12. Conclusion LABORATORY CLASSIFICATION CRITERIA

13. Challenges in Soil investigation Site Accessible Issues (Remote or congested area & Traffic and restriction (City) Unexpected ground condition Groundwater Safety and environmental assessment Logistic and equipment Human error and data accuracy

14. Thank you

15. Question & Answer?