Dome Supports for Expansive Soil Foundation Stability

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Existing methods for supporting lightly loaded structures on highly expansive soils are either expensive, time-consuming, or ineffective, particularly in developing countries where resources and expertise may be limited, and current solutions fail to adequately address the swelling pressures that cause structural damage.

Innovation Solution

A device comprising a plurality of domes with convex and concave sides, where the concave side faces the soil to create a void for expansion and the convex side supports the structure, using split PVC pipes to increase pressure exerted by the structure on the soil, thereby minimizing disturbance from soil swelling.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If soil removal and replacement is performed to support lightly loaded structures, then foundation stability is improved, but construction time and cost increase significantly

Engineering Contradiction:

Improvefoundation stabilityVSAvoidconstruction time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The foundation support system is segmented into multiple individual dome elements distributed across the foundation area. Each dome independently manages soil expansion in its local zone, allowing parallel construction and eliminating the need for extensive soil removal and replacement while maintaining overall foundation stability.

Inventive Principle:

Principle #1Segmentation

2Strength

If post-tensioned concrete slabs are used to resist swelling pressures, then structural strength is improved, but construction complexity and cost increase

Engineering Contradiction:

Improvestructural strengthVSAvoidconstruction complexity

Core Design Contradiction:

StrengthVSDevice complexity

Solution Approach 1:

The invention uses simple, inexpensive dome elements made from readily available materials such as concrete or metal. These domes are straightforward to install and do not require specialized post-tensioning equipment or expertise, making them suitable for developing countries and small projects while providing adequate structural support.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

3Reliability

If ribbed beam or waffle slab foundations with void boxes are constructed, then resistance to soil heave is improved, but material consumption and labor cost increase

Engineering Contradiction:

Improveresistance to soil heaveVSAvoidconcrete and steel consumption

Core Design Contradiction:

ReliabilityVSQuantity of substance

Solution Approach 1:

Instead of creating extensive void spaces throughout the foundation, the invention places dome elements with concave sides at specific locations where soil expansion occurs. This localized approach provides heave resistance only where needed, reducing overall material consumption while maintaining effectiveness.

Inventive Principle:

Principle #3Local quality

4Stress or pressure

If cardboard split-tubes are used to reduce contact area with soil, then swelling pressure resistance is partially improved, but the contact area reduction is insufficient for high swelling pressures

Engineering Contradiction:

Improveswelling pressure resistanceVSAvoideffectiveness in high swelling soils

Core Design Contradiction:

Stress or pressureVSReliability

Solution Approach 1:

The invention uses dome-shaped elements with curved surfaces that provide optimal geometry for resisting soil expansion. The concave side of each dome creates an air gap that accommodates soil movement, while the convex side distributes loads effectively. This spherical geometry is more effective than flat or segmented rectangular forms in managing multidirectional soil expansion forces.

Inventive Principle:

Principle #14Spheroidality (Curvature)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The solution effectively counters the swelling effects of expansive soils by increasing the pressure exerted by the structure on the soil, reducing damage to the structure and providing a cost-effective and feasible method for supporting lightly loaded structures in areas with high swelling pressures.

Implementation Method 1

Clays and claystone materials that contain montmorillonite or illite minerals have been known to swell when they absorb moisture and shrink when moisture is extracted

Methodology Applied

Scientific EffectSoil expansion:

Implementation Method 2

The soil contact ends provide a small contact area with the soil so as to increase the pressure exerted by the lightly loaded structure

Methodology Applied

Scientific EffectPressure increase:

Data Source

PatentUS8807876B2Method and device for supporting lightly loaded structures and pavements on highly expansive soils

Publication Date: 2014.08.19 AFFI LIIBAN

AI summary

A device and method for supporting lightly loaded structures on highly expansive soils. A plurality of domes is positioned between the lightly loaded structure and the soil. Each of the domes has a convex side and a concave side. The convex side faces upward against the lightly loaded structure and the concave side faces downward against the soil. The concave side provides a void area for expansion of soil. Each dome also has two soil contact ends. The soil contact ends provide a small contact area with the soil to increase the pressure exerted by the lightly loaded structure at the soil contact area to overcome the swelling effects of expanding soil. In a preferred embodiment each dome is fabricated from PVC pipe.