US4508472A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for controlling moisture-expansive clay supporting building foundations
Assignee: Iowa State University Research Foundation Inc
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Filing: 1982-11-03
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Granted: 1985-04-02
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Expires: 2002-11-03
Abstract
Abstract A method for preventing or greatly reducing damage to building foundations resulting from the swelling of moisture-expansive clay beneath and about such foundations. The method includes the steps of first forming a trench about the foundation, the trench extending well below the basement or on-grade floor slab of that foundation, and then substantially filling the trench with an extrudable plastic mass of hydrated lime and water to help stabilize the moisture-expansive clay and to provide a yieldable buffer capable of being displaced upwardly to accommodate horizontal expansion of the clay beneath and about the foundation, thereby relieving lateral stresses and reducing upward forces against the floor slab.
Inventors
- 👤 Richard L. Handy
- 👤 James A. Murray
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 15:16
CPC Classifications
E; E02; E02D; E02D31/00; E02D31/10
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
131 words
A method for preventing or reducing the heaving of a floor slab and other damage to an existing building foundation that might result from the swelling of moisture-expansive clay beneath and about such foundation, comprising the steps of trenching along the sides of said foundation to form a vertical trench having a depth extending substantially below the floor slab of said foundation; and then substantially filling said trench with a mixture of hydrated lime and water to (a) help stabilize the moisture-expansive clay beneath and about said foundation and (b) provide a yieldable mass capable of upward displacement within said trench to accommodate horizontal expansion of the clay beneath and about said foundation, thereby allowing lateral expansion of the clay below said floor slab and reducing upward pressure on said slab.
Claim 2
Independent Claim
131 words
A method for preventing or reducing the heaving of a floor slab and other damage to an existing building foundation that might result from the swelling of moisture-expansive clay beneath and about such foundation, comprising the steps of trenching along the sides of said foundation to form a vertical trench having a depth extending substantially below the floor slab of said foundation; and then substantially filling said trench with a mixture of hydrated lime and water to (a) help stabilize the moisture-expansive clay beneath and about said foundation and (b) provide a yieldable mass capable of upward displacement within said trench to accommodate horizontal expansion of the clay beneath and about said foundation, thereby allowing lateral expansion of the clay below said floor slab and reducing upward pressure on said slab.
Claim 3
Dependent Claim
47 words
The method of claim 1 in which said mixture is prepared outside of said trench by mixing hydrated lime and water to form a thick homogeneous hydrated lime slurry; said hydrated lime and water then being introduced into said trench in slurry form during said filling step.
Claim 4
Dependent Claim
45 words
The method of claim 1 in which said mixture is prepared within said trench by individually introducing water and solid, finely-divided hydrated lime into said trench, and then mixing said lime and water in situ to form a thick hydrated lime slurry within said trench.
Claim 5
Independent Claim
26 words
The method of claims 2 or 3 in which said slurry comprises a mixture of hydrated lime and approximately 20 to 60 percent by weight water.
Claim 6
Dependent Claim
22 words
The method of claim 1 in which said trenching includes forming a substantially continuous trench about the perimeter of said building foundation.
Claim 7
Independent Claim
18 words
The method of claims 1 or 5 in which said trench is spaced substantially uniformly from said foundation.
Claim 8
Dependent Claim
26 words
The method of claim 6 in which said trench is uniformly spaced from said foundation a distance within the range of about 0.5 to 8.0 feet.
Claim 9
Dependent Claim
18 words
The method of claim 7 in which said spacing is within the range of 1 to 3 feet.
Claim 10
Dependent Claim
21 words
The method of claim 1 in which said trench has a width falling within the range of 2 to 12 inches.
Claim 11
Dependent Claim
20 words
The method of claim 9 in which said trench has a width within the range of 3 to 5 inches.
Claim 12
Dependent Claim
14 words
The method of claim 1 in which said trench is of substantially uniform depth.
Claim 13
Dependent Claim
24 words
The method of claim 11 in which said trench has a uniform depth at least 6 inches below said floor slab of said foundation.
Claim 14
Independent Claim
44 words
The method of claims 1 or 5 in which there is the further step of forming a second vertical trench parallel with and spaced outwardly from said first-mentioned trench, and then substantially filling said second trench with said mixture of hydrated lime and water.
Claim 15
Dependent Claim
29 words
The method of claim 13 in which said second trench is spaced uniformly outwardly from said first trench a distance within the range of approximately 2 to 8 feet.
Claim 16
Dependent Claim
25 words
The method of claim 14 in which the spacing between said first and second trench falls within the range of approximately 3 to 5 feet.
Claim 17
Dependent Claim
21 words
The method of claim 13 in which said second trench extends to substantially the same uniform depth as said first trench.
References Cited (Backward Citations)
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1988-04-01 | 1988-10-01 | 1989-04-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-04-01 | 1992-10-01 | 1993-04-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-04-01 | 1996-10-01 | 1997-04-02 | $7700.00 | Window Closed / Lapsed |