Weight-Volume Relationships
Prepared by: aidsalma@feng.unimas.my
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Introduction
• Soil is a three-phase material consisting of a skeleton of solid particles. • The solid particles encompassing voids filled with water & air. • It is necessary that the constitution of the solidswater-air mixture can be expressed quantitatively in terms of some standard physical properties. • Soil water is commonly known as pore water • If all voids are filled with water = soil is saturated, otherwise will be known as soil is unsaturated. (not all voids are filled with water) • If all voids are filled with air = soil is dry Prepared by:aidsalma@feng.unimas.my 2
At the end of lecture, students should be able to:
• Determine the proportions of the main constituents in a soil • Determine particle size distribution in a soil mass • Classify soils • Determine index properties of soils
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Definition of Key Terms
• Water content (w) is the ratio of the weight of water to the weight of solids • Void ratio (e) is the ratio of the volume of voids to the volume of solids • Porosity (n) is the ratio of the volume of voids to the total volume of soil • Degree of saturation(Sr) is the ratio of the volume of water to the volume of voids • Bulk unit weight (γbulk) is the weight density, the weight of a soil per unit volume • Saturated unit weight (γsat) is the weight of a saturated soil per unit volume • Dry unit weight (γdry) is the weight of a dry soil per unit volume • Effective unit weight (γ') is the weight of soil solids in a submerged soil per unit volume
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Weight-volume relationships
• Soil can be idealized in 3 phases as shown in Fig.1. • The physical properties of soils are influenced by the relative proportions of each of these phases.
Solids
Va Void Air Wa
V
Vw
Water
Ww
W
Vs
Solids
Ws
Fig. 1
idealization
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