Geotechnical Engineering Simulations

A collection of interactive 3D visualizations and simulations to help you master concepts in geotechnical engineering.

Soil Composition - Theory & Concepts

Understanding the three-phase system of soil: solids, water, and air, and their volumetric and weight relationships.

Soil Phase Diagram (Three-Phase System)

Input Parameters

Volume of Solids (Vs)1.00

Volume of Water (Vw)0.50

Volume of Air (Va)0.20

Specific Gravity (Gs)2.65

Adjusting volumes changes the Void Ratio ( $e$ ) and Porosity ( $n$ ). Adjusting water changes Saturation ( $S$ ) and Water Content ( $w$ ).

Calculated Ratios

Void Ratio (e)Vv / Vs

0.700

Porosity (n)Vv / Vt

41.2%

Degree of Saturation (S)Vw / Vv

71.4%

Water Content (w)Ww / Ws

18.9%

Unit Weights (kN/m³)

Moist Unit Wt (γ)

18.18

Dry Unit Wt (γd)

15.29

Saturated Unit Wt (γsat)

19.33

Soil Classification - Theory & Concepts

Systems for categorizing soils based on particle size and plasticity, including USCS and AASHTO.

Aggregate Gradation Curve

Loading chart...

Interpretation:

A well-graded soil has a good representation of particle sizes over a wide range. This leads to high density and stability as smaller particles fill the voids between larger ones. Best for structural fill and base courses.

Soil Compaction - Theory & Concepts

Methods to increase soil density, including Proctor tests and field compaction control.

Consolidation Acceleration with PVDs

Clay Thickness,

H

(m): 10

C_v

(m²/yr): 2.0

Install Prefabricated Vertical Drains (PVD)

PVD Spacing,

s

(m): 1.5

Time to 90% Consolidation (

t_{90}

)

0.0 months

Accelerated via radial drainage!

Without drains, water must travel vertically through the entire clay layer (slow). Prefabricated Vertical Drains (PVDs) shorten the drainage path to half the spacing distance, converting vertical flow to rapid radial flow. Notice how settlement time drops from years to months.

Flow Nets and Seepage Analysis - Theory & Concepts

Graphical representation of groundwater flow through soil media using flow nets.

Flow Net Calculator under Sheet Pile

Number of Flow Channels (

N_f

): 4

Number of Potential Drops (

N_d

): 10

Total Head difference

H

(m): 15

Permeability

k

(cm/s): 5.00e-3

Shape Factor ( $N_f / N_d$ )

0.40

Total Seepage ( $q$ )

0.0300

cm³/s per cm of wall

Effective Stress - Theory & Concepts

The principle of effective stress and its importance in soil strength and deformation.

Effective Stress Profile

Parameters

Water Table Depth (m)5.0

Layer 1 Unit Weight (kN/m³)16.0

Layer 2 Unit Weight (kN/m³)19.0

Layer 1: 0-4m (Sand)
Layer 2: 4-10m (Clay)
Observe how raising the water table increases pore pressure ( $u$ ) and decreases effective stress ( $\\sigma'$ ).

Compressibility and Consolidation - Theory & Concepts

Soil settlement analysis, one-dimensional consolidation theory, and time rate of settlement.

Interactive Consolidation Lab

Clay Layer Thickness,

H

(10 m)

Drainage Condition

Double (Sand Top & Bottom)Single (Rock Bottom)

Install Prefabricated Vertical Drains (PVDs)

Time to 90% Consolidation ( $U=90\\%$ )

0.00 years

Excellent! Construction can proceed quickly.

Sand / Fill (Drainage)

SOFT CLAY

Sand (Drainage)

Shear Strength - Theory & Concepts

Mohr-Coulomb failure criterion, shear strength parameters, and laboratory testing methods.

Mohr-Coulomb Failure Criterion

Stable

Major Stress (σ₁)100

Minor Stress (σ₃)40

Cohesion (c)10

Friction Angle (φ)30 °

If the circle touches or crosses the red failure envelope, the soil fails in shear. The radius of the circle represents the maximum shear stress ( $\\tau_{max} = (\\sigma_1 - \\sigma_3)/2$ ).

Soil Exploration - Theory & Concepts

Site investigation methods, boring techniques, and field testing (SPT, CPT, PMT).

SPT N-Value Correction Calculator

Field Blow Count,

N_{field}

: 15

Hammer Efficiency,

\\eta_H

(%): 60

Rod Length (m): 5

Test Depth,

z

(m): 5

Soil Unit Weight,

\\gamma

(kN/m³): 18

Energy-Corrected Blow Count

N_{60}

= 0.0

Accounts for hammer efficiency and rod length.

Overburden Correction Factor

C_N

= 0.00

Normalizes to 100 kPa effective stress.

Fully Corrected Blow Count

(N_1)_{60}

= 0

Used for design correlations (e.g., relative density, bearing capacity).

The Standard Penetration Test (SPT) involves dropping a 140 lb hammer 30 inches. Different hammers transfer energy differently. The $N_{60}$ normalizes this to 60% theoretical free-fall energy. $C_N$ adjusts for depth, because soil at greater depths appears artificially stronger due to confinement.

Lateral Earth Pressure - Theory & Concepts

Calculation of lateral forces on retaining structures using Rankine, Coulomb, and Culmann theories.

Gravity Retaining Wall Stability

Wall Height, H (m): 5

Base Width, B (m): 3

Soil Friction,

\\phi

(deg): 30

FS Overturning

0.00

Target: ≥ 2.0

FS Sliding

0.00

Target: ≥ 1.5

The red dashed line represents the Rankine failure plane. The red arrow represents the active earth pressure ( $P_a$ ), which tries to overturn and slide the wall. The blue arrow represents the weight ( $W$ ), which provides resistance.

Retaining Walls - Theory & Concepts

Design and stability analysis of gravity, cantilever, and sheet pile retaining walls.

Gravity Retaining Wall Stability

Wall Height, H (m): 5

Base Width, B (m): 3

Soil Friction,

\\phi

(deg): 30

FS Overturning

0.00

Target: ≥ 2.0

FS Sliding

0.00

Target: ≥ 1.5

Slope Stability - Theory & Concepts

Analysis of slope failure mechanisms using infinite slope and method of slices.

Slope Stability Calculator

FS = 1.04

Gravity

Normal

Friction

Slope Angle (β)30 °

Friction Angle (φ)25 °

Cohesion (c)10 kPa

Soil Density (γ)20 kN/m³

Depth to Failure (z)5 m

Resisting Stress45.0 kPa

Driving Stress43.3 kPa

Bearing Capacity - Theory & Concepts

Estimation of the ultimate bearing capacity of shallow foundations using Terzaghi's and general equations.

Bearing Capacity Simulator (Square Footing)

Width, B (m): 2

Depth, Df (m): 1

Friction Angle,

\\phi

(deg): 30

Cohesion, c (kPa): 10

Ultimate Bearing Capacity

0.0 kPa

Calculated using Terzaghi's formula for square footing.

The red dashed lines represent the potential shear failure surface in the soil. As $\\phi$ increases, the failure surface extends further outward, mobilizing more soil resistance.

Design of Shallow Foundations - Theory & Concepts

Design considerations for isolated, combined, and mat foundations, including structural design and settlement checks.

Shallow Foundation Sizing & Pressure

Axial Load,

P

(kN): 1000

Overturning Moment,

M

(kN·m): 0

Allowable Bearing,

q_{all}

(kPa): 150

Required Square Width (

B

)

0.0 m

Maximum Soil Pressure (

q_{max}

)

0.0 kPa

Eccentricity (

e = M/P

)

0.00 mLimit

B/6

: 0.00 m

The simulator automatically increases the footing width ( $B$ ) until the maximum soil pressure ( $q_{max}$ ) is below the allowable bearing capacity. When a moment is applied, the pressure becomes trapezoidal. If eccentricity ( $e$ ) exceeds $B/6$ , tension develops at the heel (shown as $q_{min} = 0$ ).

Deep Foundations - Theory & Concepts

Introduction to pile foundations, load transfer mechanisms, and pile capacity calculations.

Single Pile Capacity Estimator

Pile Length, L (m): 10

Pile Diameter, D (m): 0.5

Friction Angle,

\\phi

(deg): 30

Total Capacity (

Q_u

)

0 kN

Skin Friction (

Q_s

)0 kN

Tip Resistance (

Q_p

)0 kN

Using Beta Method for skin friction and Nq method for tip resistance.

Blue arrows represent skin friction resistance ( $Q_s$ ) acting along the shaft. The red arrow represents point bearing resistance ( $Q_p$ ) acting at the tip.

Soil Improvement - Theory & Concepts

Techniques for enhancing soil properties, including preloading, grouting, and reinforcement.

Interactive Consolidation Lab

Clay Layer Thickness,

H

(10 m)

Drainage Condition

Double (Sand Top & Bottom)Single (Rock Bottom)

Install Prefabricated Vertical Drains (PVDs)

Time to 90% Consolidation ( $U=90\\%$ )

0.00 years

Excellent! Construction can proceed quickly.

Sand / Fill (Drainage)

SOFT CLAY

Sand (Drainage)

Soil Dynamics and Liquefaction - Theory & Concepts

Understanding the behavior of soils under dynamic loading and the phenomenon of liquefaction.

Soil Liquefaction Potential Simulation

Earthquake Peak Ground Acceleration (PGA): 0.20 g

Relative Density index (proxy): 1.50

Lower values = looser sand, Higher values = denser sand.

Analysis Results

Cyclic Stress Ratio (CSR) $\\approx$ 0.20

Cyclic Resistance Ratio (CRR) $\\approx$ 0.30

Factor of Safety (FS) = 1.54

Safe: No Liquefaction expected.

Building

Geotechnical Engineering Simulations

Soil Composition - Theory & Concepts

Soil Phase Diagram (Three-Phase System)

Input Parameters

Calculated Ratios

Unit Weights (kN/m³)

Soil Classification - Theory & Concepts

Aggregate Gradation Curve

Soil Compaction - Theory & Concepts

Consolidation Acceleration with PVDs

Flow Nets and Seepage Analysis - Theory & Concepts

Flow Net Calculator under Sheet Pile

Effective Stress - Theory & Concepts

Effective Stress Profile

Parameters

Compressibility and Consolidation - Theory & Concepts

Interactive Consolidation Lab

Time to 90% Consolidation (U=90U=90\\%U=90)

Shear Strength - Theory & Concepts

Mohr-Coulomb Failure Criterion

Soil Exploration - Theory & Concepts

SPT N-Value Correction Calculator

Lateral Earth Pressure - Theory & Concepts

Gravity Retaining Wall Stability

Retaining Walls - Theory & Concepts

Gravity Retaining Wall Stability

Slope Stability - Theory & Concepts

Slope Stability Calculator

Bearing Capacity - Theory & Concepts

Bearing Capacity Simulator (Square Footing)

Design of Shallow Foundations - Theory & Concepts

Shallow Foundation Sizing & Pressure

Deep Foundations - Theory & Concepts

Single Pile Capacity Estimator

Soil Improvement - Theory & Concepts

Interactive Consolidation Lab

Time to 90% Consolidation (U=90U=90\\%U=90)

Soil Dynamics and Liquefaction - Theory & Concepts

Soil Liquefaction Potential Simulation

Analysis Results

Time to 90% Consolidation ( $U=90\\%$ )

Time to 90% Consolidation ( $U=90\\%$ )