Chapter 4 Geosynthetics materials for soil improvement .pptx

Geosynthetics are synthetic polymeric materials used in geotechnical, transportation, environmental, and hydraulic engineering applications to enhance the performance of soils. They are widely used because of their durability, versatility, and cost-effectiveness in improving the engineering properties of weak or problematic soils.

1. www.huawei.com Geotechnical Engineering Design - I I Chapter 4 Geosynthetics By: Fenta Nebiyou (MSc. in Geotechnical Engineering) 1

2. 1. Introduction Geosynthetics are polymeric (plastic) man-made products used to solve geotechnical problems in construction projects . Geosynthetics are derived from two words, those are: Geo: Soil, Rock or other Geotechnical material Synthetic: Man made Polymeric material Geosynthetics = human made materials (polymers) used with soil, rock, earth or other geotechnical materials as an essential part of a project, structure or system. 2

3. 3. Properties of Geosynthetics a . Physical The physical properties are important to assess the nature and type of geosynthetics product. Those are: Thickness , Specific Gravity, Mass per unit area, Porosity , Percent open area, Apparent opening size. 43

4. b . Chemical The chemical properties are important to assess the nature and type of geosynthetics product. Those are: Polymer type, Filler material, Carbon black percentage, Plasticizers and additives, Manufacturing process. 44 Properties of Geosynthetics

5. c. Mechanical The strength and deformation characteristics of the geosynthetics are investigated through mechanical properties. These properties help to understand the performance of geosynthetics under different loading conditions without tearing, yielding, puncturing, and slipping at the soil- geosynthetic interface. Those are: Tensile strength, Compressibility , Elongation , Tear/impact/puncture resistance, Burst strength, Seam strength, Fatigue resistance, Interface friction with soil. 45 Properties of Geosynthetics

6. d. Hydraulic Hydraulic properties are useful in quantifying the amount of water that can flow through the geosynthetics through the in-plane and cross-plane directions. Those are: Permittivity (cross plane permeability), Transmissivity (in plane permeability), and Clogging potential. 46 Properties of Geosynthetics

7. e. Endurance Endurance properties suggest that the creep behavior and construction survivability of geosynthetics . Those are: Tear/impact/puncture resistance, Abrasion resistance, Creep . 47 Properties of Geosynthetics

8. f. Degradation Degradation properties are useful for assessing the change in performance of geosynthetics with time (for example, exposure to oxidation or ultra-violate rays in sunlight for longer duration may affect its performance). Those are: Ultraviolet radiation, Temperature , Oxidation , Aging , Chemical and Biological reactions. 48 Properties of Geosynthetics