This document discusses soil structure and its types. It describes four main types of soil structure: single grained, honey-comb, flocculated, and dispersed. Single grained structure refers to loosely or densely packed soil grains. Honey-comb structure occurs in fine-grained soils that form particle-to-particle contacts bridging voids. Flocculated structure involves clay particles with attractive interparticle forces forming edge-to-face orientations. Dispersed structure involves repulsive forces between clay particles forming face-to-face orientations. The document also introduces the three-phase diagram used to represent the solid, liquid, and gas components of soil.

1. MGMU’s JNEC Civil Engineering Department Faculty Name A S Pawar Subject Geotechnical Engineering Date 01-01-2024
SOIL STRUCTURE

2. MGMU’s JNEC Civil Engineering Department Faculty Name A S Pawar Subject Geotechnical Engineering Date 01-01-2024
 It is geometrical arrangement of soil particles in a soil mass. The behavior of
soil depends on the soil structure.
 The soils in nature have different structures depending upon the particle size
and the mode of formation.
 There are four types
• Single grained structure
• Honey-Comb structure
• Flocculated structure
• Dispersed structure

3. MGMU’s JNEC Civil Engineering Department Faculty Name A S Pawar Subject Geotechnical Engineering Date 01-01-2024
• Cohesion less soils, such as gravel and sand,
are composed of bulky grains.
• When deposition occurs, the particles settle
under gravitational forces and take an
equilibrium position.
• If particles are assumed as spheres, the
loosest and densest packaging are shown
aside.
SINGLE GRAINED STRUCTURE
Looseststate
Denseststate

4. MGMU’s JNEC Civil Engineering Department Faculty Name A S Pawar Subject Geotechnical Engineering Date 01-01-2024
• It is possible for fine sands or silts.
• The soils are deposited such that the particles when setting develop a particle-to-
particle contact that bridges over large voids in the soilmass.
• The honeycomb structure usually develops when the particle size is between 0.002 mm and
0.02 mm.
• Under vibrations and shocks the structurecollapses
and large deformation takes place.
HONEY-COMB STRUCTURE

5. MGMU’s JNEC Civil Engineering Department Faculty Name A S Pawar Subject Geotechnical Engineering Date 01-01-2024
• If the inter particle force are attractive, then particles want to come together, making
flocculated clay.
• If the edge charges are positive, most likely, theedges are attracted to the flat surface of
other clay particles.
• Formed when there is a net attractive force between the particles.
• Edge to face orientation.
• Has high shear strength, low compressibility and
high permeability.
FLOCCULATED STRUCTURE

6. MGMU’s JNEC Civil Engineering Department Faculty Name A S Pawar Subject Geotechnical Engineering Date 01-01-2024
• It occurs in remolded clays
• Face to Face orientation
• Formed when there is net repulsive forces between particles.
• Has low shear strength, high compressibility and low permeability.
DISPERSED STRUCTURE

7. MGMU’s JNEC Civil Engineering Department Faculty Name A S Pawar Subject Geotechnical Engineering Date 01-01-2024
• Soil consist of solid particles which
form a porous structure.
• The voids in the soil mass maybe filled
with air, with water or partly with air and
partly with water.
• The three constituents are blended to
form complex material.
CONSTITUENTS OF SOIL

8. MGMU’s JNEC Civil Engineering Department Faculty Name A S Pawar Subject Geotechnical Engineering Date 01-01-2024
• For convenience, all solid particles are
segregated and placed in the lower layer
of the three-phase diagram.
• Three phase diagram also known as block
diagram.
• It is used for easy understanding and
convenience in calculation
THREE PHASE DIAGRAM OF SOIL

9. MGMU’s JNEC Civil Engineering Department Faculty Name A S Pawar Subject Geotechnical Engineering Date 01-01-2024
• When soil is dry, the water phase disappears.
• When soil is fully saturated there is no air
phase.
• Phase diagram is a simple diagrammatic
representation of real soil.
TWO PHASE DIAGRAM OF SOIL

10. MGMU’s JNEC Civil Engineering Department Faculty Name A S Pawar Subject Geotechnical Engineering Date 01-01-2024
Va = Volume of air
Wa = Weight of air (negligible or zero)
Vw = Volume of water
Ww = Weight of water
Vv = Volume of voids
Wv = Weight of material occupying void space
Wv = Ww
THREE PHASE DIAGRAM OF SOIL
Vs = Volume of solids
Ws = Weight of solids
VT = Total volume of soil mass
WT = Total weight of solid mass

11. MGMU’s JNEC Civil Engineering Department Faculty Name A S Pawar Subject Geotechnical Engineering Date 01-01-2024
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