Indian Patents. 254094:A METHOD OF PRODUCING A CAVITY FOR FORMATION OF ENGINEERED AGGREGATE PIERS

Title of Invention	A METHOD OF PRODUCING A CAVITY FOR FORMATION OF ENGINEERED AGGREGATE PIERS
Abstract	The invention relates to a method of producing a cavity for formation of engineered aggregate piers. In particulars, this invention relates to a method of reinforcing of a cavity by the step of soil stabilization.

Full Text	FIELD OF INVENTION This invention relates to a method of producing a cavity for formation of engineered aggregate piers. In particulars, this invention relates to a method of reinforcing of a cavity by the step of soil stabilization. BACKGROUND OF INVENTION It is generally known that a foundation system for supporting a superstructure may either be a deep or shallow system, the depth to width ratio generally defining said system. The choice of the foundation is dependant on the load and as to whether the soil can carry loads with adequate factor of safety with respect to shear and settlement. Normally, if the soil does not have adequate supporting capacity to withstand the load, a deep foundation system is preferred or ground improvement needs are followed even if the load is not too considerable. Thus, the choice of the foundation system is not dependant only on the load, but also on the supporting capacity of the soil with an adequate factor of safety. Deep foundations may be formed by driving a precast RCC or a steel pile. Alternatively, tube or casing may be driven into the soil, and whereby the soil is laterally displaced, and thereby resulting in a densification of the adjoining soil. A reinforcement cage is introduced into the tube or casing and, thereafter, concrete is poured into said tube or casing The casing or tube is slowly withdrawn by tamping with a hammer. Yet another method of forming a deep foundation system is to introduce an auger into the soil. However, in such a method, the soil is removed and a temporary casing is introduced so as to prevent a collapse of the wall of the formed cavity. Alternatively, bentonite slurry may be circulated within the cavity. After lowering the reinforcement cage, concrete is poured into the cavity to form cast in situ piles. Alternatively, precast piles may be introduced into said cavity followed by grouting. Shallow foundations are less complicated but have a limitation in withstanding the load, unless soil resistance is substantial. Shallow foundations normally comprise column footings or load bearing walls or raft foundations. Yet another method of forming a foundation has been disclosed in U.S. Patent No. 5,249892. In the method of U.S. Patent No. 5,249,g92, a cavity having a bottom and side walls is formed. The soil in the proximity of the base or bottom of the cavity is compacted so as to prestress and densify the adjacent soil. Such a step of compaction is of importance as the bottom portion of the cavity is required to withstand the forces exerted on the aggregates during the step of ramming. Such aggregates normally consisting of stone are introduced in a stepwise manner such as to form a plurality of layers disposed along the vertical axis to constitute an aggregate pier, each layer being formed by introduction of such aggregates and then subjected to a step of ramming by a tamping tool. As the force exerted by the tamping tool is eventually transferred to the lowermost layer, it would be apparent that if the adjoining and bottom soil of the lowermost layer is unable to withstand such a force, the adjoining soil within the cavity does not get stiffened. Thus, one of the important steps disclosed in U.S. Patent No. 5,249,892 is of compacting the soil in the vicinity of the bottom portion. Thereafter, a plurality of layers, each having a predetermined height is formed by introducing stone aggregates and then causing a compaction of each layer by a tamping tool. It would be apparent that the step of ramming with high energy level results in increase in lateral pressures with a limiting value being equal to passive pressure. The present invention is essentially concerned with a stabilization of the cavity. OBJECTS OF INVENTION An object of this invention is to provide a method of stabilization of the cavity for aggregate piers. Another object of this invention is to propose a method of stabilization of the cavity without imparting any additional force other than that known in the art. Yet another object of this invention is to provide a method for stabilization of the cavity which is efficient. DESCRIPTION OF INVENTION According to this invention there is provided a method of stabilizing the soil of at least the base of the cavity for formation of engineered aggregate piers which comprises in introducing with the aggregate forming the lowermost layer, introducing soil stabilizing agents such as calcium chloride, a solidifier/binder such as sodium silicate with or without calcium chloride, a tackifier such as chrome lignin, cement, lime, a mixture of lime and pozzolonic material such as flyash with or without calcium chloride, krilium and a carrier for said agents. Though the method of producing short aggregate piers is known from U.S. Patent No. 5,249,892, such a known process has the disadvantage of soil stability in the vicinity of the base of the cavity. As described hereinabove, such a stability particularly at the base of the cavity is of importance as the short aggregate piers disposed along the vertical axis are supported on the bed or base of the cavity and consequentially any subsequent displacement of the base or cavity wall forming the base portion can detrimentally affect the stiffness characteristics of piers and matrix soil. Such a disadvantage is obviated by the soil stabilization process of the present invention. The soil stabilization process of the present invention comprises in a chemical treatment of the soil with or without the known process of compacting the aggregates to densify and laterally prestress the adjoining soil of the lowermost layer and, if required, that of the walls of the cavity. In accordance with this invention, the chemical treatment consists in introducing the constituents individually or as an admixture. The constituents comprise soil stabilizing agents such as calcium chloride and present in an amount of 1-5% by weight of soil. The constituents further comprise a solidifier or binder such as sodium silicate with or without calcium chloride and present in an amount of 2 to 10%. Chrome lignin acts as a tackifier and present in an amount of upto 10% by weight of soil and preferably 2 to 10%. The constituents further comprise cement and/or hydrated lime which interacts with clay particles and binds the particles. Lime is present in an amount of 2 to 4% by weight of soil. In the instance of cement, it is present in an amount upto 15% by wt. of soil, and preferably 6 to 15%. Pozzolonic material, such as flyash and lime is added in an amount of 2 to 5% in combination or singularly with or without calcium chloride in an amount of 0.1 to 2%. Resins such as vinsol or formaldehyde, may be added also as a constituent and present in an amount of 1 to 10% by weight of soil. Such constituents are added individually or as an admixture. Reference is made herein to the constituents. Such constituents are introduced with a carrier comprising a particulate material such as sand. Besides being a carrier, sand has the additional advantage of filling the voids between adjacent aggregates and thereby increasing the strength properties. WE CLAIM: 1. A method of stabilizing the soil of at least the base of the cavity for formation of engineered aggregate piers which comprises in introducing with the aggregate forming the lowermost layer, introducing soil stabilizing agents such as calcium chloride, a solidifier/binder such as sodium silicate with or without calcium chloride and a tackifier such as chrome lignin, cement, lime, a mixture of lime and pozzolonic material such as fiyash with or without calcium chloride krilium and a earner for said agents. 2. A method as claimed in claim 1 wherein calcium chloride is present in an amount of 1 to 5% by wt of soil. 3. A method as claimed in claim 1 wherein said pozzolonic material comprises fiyash and lime present in an amount of 2 to 5% by wt. of soil in combination or singularly with or without calcium chloride. 4. A method as claimed in claim 1 wherein said cement is present in an amount of upto 15% and preferably 6 to 15% by wt. of soil. 5. A method as claimed in claim 1 wherein said carrier is sand. 6. A method as claimed in claim 1 wherein said cement and/or hydrated lime is present in an amount of 1 to 5% by wt. of soil. 7. A method as claimed in claim 1 wherein said binder or solidifier is present in an amount of 1 to 5% by wt. of soil. 8. A method as claimed in claim 1 wherein krilium is present in an amount of 0.1 to 2% by wt. of soil. 9. A method as claimed in claim 1 comprising resins such as vinsol or formal dehyde. 10. A method as claimed in claim 1 wherein said tackifier is chrome lignin and present in an amount of upto 10% by wt. of soil. 11. A method of stabilizing the soil of at least the base cavity for formation of engineered aggregate piers substantially as herein described. The invention relates to a method of producing a cavity for formation of engineered aggregate piers. In particulars, this invention relates to a method of reinforcing of a cavity by the step of soil stabilization.

Full Text

FIELD OF INVENTION
This invention relates to a method of producing a cavity for formation of engineered
aggregate piers. In particulars, this invention relates to a method of reinforcing of a
cavity by the step of soil stabilization.
BACKGROUND OF INVENTION
It is generally known that a foundation system for supporting a superstructure may
either be a deep or shallow system, the depth to width ratio generally defining said
system. The choice of the foundation is dependant on the load and as to whether the
soil can carry loads with adequate factor of safety with respect to shear and settlement.
Normally, if the soil does not have adequate supporting capacity to withstand the load, a
deep foundation system is preferred or ground improvement needs are followed even if
the load is not too considerable. Thus, the choice of the foundation system is not
dependant only on the load, but also on the supporting capacity of the soil with an
adequate factor of safety.
Deep foundations may be formed by driving a precast RCC or a steel pile.
Alternatively, tube or casing may be driven into the soil, and whereby the soil is
laterally displaced, and thereby resulting in a densification of the adjoining soil. A
reinforcement cage is introduced into the tube or casing and, thereafter, concrete is
poured into said tube or casing The casing or tube is slowly withdrawn by tamping with
a hammer.
Yet another method of forming a deep foundation system is to introduce an auger into
the soil. However, in such a method, the soil is removed and a temporary casing is
introduced so as to prevent a collapse of the wall of the formed cavity. Alternatively,
bentonite slurry may be circulated within the cavity. After lowering the reinforcement
cage, concrete is poured into the cavity to form cast in situ piles. Alternatively, precast
piles may be introduced into said cavity followed by grouting.
Shallow foundations are less complicated but have a limitation in withstanding the
load, unless soil resistance is substantial. Shallow foundations normally comprise
column footings or load bearing walls or raft foundations.
Yet another method of forming a foundation has been disclosed in U.S. Patent No.
5,249892. In the method of U.S. Patent No. 5,249,g92, a cavity having a bottom and
side walls is formed. The soil in the proximity of the base or bottom of the cavity is
compacted so as to prestress and densify the adjacent soil. Such a step of compaction is
of importance as the bottom portion of the cavity is required to withstand the forces
exerted on the aggregates during the step of ramming. Such aggregates normally
consisting of stone are introduced in a stepwise manner such as to form a plurality of
layers disposed along the vertical axis to constitute an aggregate pier, each layer being
formed by introduction of such aggregates and then subjected to a step of ramming by a
tamping tool. As the force exerted by the tamping tool is eventually transferred to the
lowermost layer, it would be apparent that if the adjoining and bottom soil of the
lowermost layer is unable to withstand such a force, the adjoining soil within the
cavity does not get stiffened. Thus, one of the important steps disclosed in U.S.
Patent No. 5,249,892 is of compacting the soil in the vicinity of the bottom portion.
Thereafter, a plurality of layers, each having a predetermined height is formed by
introducing stone aggregates and then causing a compaction of each layer by a tamping
tool. It would be apparent that the step of ramming with high energy level results in
increase in lateral pressures with a limiting value being equal to passive pressure.
The present invention is essentially concerned with a stabilization of the cavity.
OBJECTS OF INVENTION
An object of this invention is to provide a method of stabilization of the cavity for
aggregate piers.
Another object of this invention is to propose a method of stabilization of the cavity
without imparting any additional force other than that known in the art.
Yet another object of this invention is to provide a method for stabilization of the
cavity which is efficient.
DESCRIPTION OF INVENTION
According to this invention there is provided a method of stabilizing the soil of at least
the base of the cavity for formation of engineered aggregate piers which comprises in
introducing with the aggregate forming the lowermost layer, introducing soil stabilizing
agents such as calcium chloride, a solidifier/binder such as sodium silicate with or
without calcium chloride, a tackifier such as chrome lignin, cement, lime, a mixture of
lime and pozzolonic material such as flyash with or without calcium chloride, krilium
and a carrier for said agents.
Though the method of producing short aggregate piers is known from U.S. Patent No.
5,249,892, such a known process has the disadvantage of soil stability in the vicinity of
the base of the cavity. As described hereinabove, such a stability particularly at the base
of the cavity is of importance as the short aggregate piers disposed along the vertical
axis are supported on the bed or base of the cavity and consequentially any subsequent
displacement of the base or cavity wall forming the base portion can detrimentally affect
the stiffness characteristics of piers and matrix soil. Such a disadvantage is obviated by
the soil stabilization process of the present invention.
The soil stabilization process of the present invention comprises in a chemical treatment
of the soil with or without the known process of compacting the aggregates to densify
and laterally prestress the adjoining soil of the lowermost layer and, if required, that of
the walls of the cavity.
In accordance with this invention, the chemical treatment consists in introducing the
constituents individually or as an admixture.
The constituents comprise soil stabilizing agents such as calcium chloride and present
in an amount of 1-5% by weight of soil. The constituents further comprise a solidifier
or binder such as sodium silicate with or without calcium chloride and present in an
amount of 2 to 10%. Chrome lignin acts as a tackifier and present in an amount of
upto 10% by weight of soil and preferably 2 to 10%. The constituents further comprise
cement and/or hydrated lime which interacts with clay particles and binds the
particles. Lime is present in an amount of 2 to 4% by weight of soil. In the instance
of cement, it is present in an amount upto 15% by wt. of soil, and preferably 6 to 15%.
Pozzolonic material, such as flyash and lime is added in an amount of 2 to 5% in
combination or singularly with or without calcium chloride in an amount of 0.1 to 2%.
Resins such as vinsol or formaldehyde, may be added also as a constituent and present
in an amount of 1 to 10% by weight of soil. Such constituents are added individually or
as an admixture.
Reference is made herein to the constituents. Such constituents are introduced with a
carrier comprising a particulate material such as sand. Besides being a carrier, sand
has the additional advantage of filling the voids between adjacent aggregates and
thereby increasing the strength properties.
WE CLAIM:
1. A method of stabilizing the soil of at least the base of the cavity for formation
of engineered aggregate piers which comprises in introducing with the
aggregate forming the lowermost layer, introducing soil stabilizing agents such as
calcium chloride, a solidifier/binder such as sodium silicate with or without
calcium chloride and a tackifier such as chrome lignin, cement, lime, a mixture
of lime and pozzolonic material such as fiyash with or without calcium
chloride krilium and a earner for said agents.
2. A method as claimed in claim 1 wherein calcium chloride is present in an
amount of 1 to 5% by wt of soil.
3. A method as claimed in claim 1 wherein said pozzolonic material comprises
fiyash and lime present in an amount of 2 to 5% by wt. of soil in combination
or singularly with or without calcium chloride.
4. A method as claimed in claim 1 wherein said cement is present in an amount of
upto 15% and preferably 6 to 15% by wt. of soil.
5. A method as claimed in claim 1 wherein said carrier is sand.
6. A method as claimed in claim 1 wherein said cement and/or hydrated lime is
present in an amount of 1 to 5% by wt. of soil.
7. A method as claimed in claim 1 wherein said binder or solidifier is present in
an amount of 1 to 5% by wt. of soil.
8. A method as claimed in claim 1 wherein krilium is present in an amount of 0.1
to 2% by wt. of soil.
9. A method as claimed in claim 1 comprising resins such as vinsol or formal
dehyde.
10. A method as claimed in claim 1 wherein said tackifier is chrome lignin and
present in an amount of upto 10% by wt. of soil.
11. A method of stabilizing the soil of at least the base cavity for formation of
engineered aggregate piers substantially as herein described.

The invention relates to a method of producing a cavity for formation of engineered
aggregate piers. In particulars, this invention relates to a method of reinforcing of a cavity
by the step of soil stabilization.

Documents:

470-CAL-2001-(19-03-2012)-AMANDED CLAIMS.pdf

470-CAL-2001-(19-03-2012)-CORRESPONDENCE.pdf

470-cal-2001-abstract 1.2.pdf

470-cal-2001-abstract-1.1.pdf

470-cal-2001-abstract.pdf

470-cal-2001-amanded claims 1.1.pdf

470-cal-2001-amanded claims.pdf

470-cal-2001-cancelled pages-1.1.pdf

470-cal-2001-claims.pdf

470-cal-2001-correspondence 1.2.pdf

470-CAL-2001-CORRESPONDENCE 1.3.pdf

470-CAL-2001-CORRESPONDENCE-1.1.pdf

470-CAL-2001-CORRESPONDENCE.pdf

470-cal-2001-description (complete)-1.1.pdf

470-cal-2001-description (complete).pdf

470-CAL-2001-EXAMINATION REPORT.pdf

470-CAL-2001-FORM 1 1.2.pdf

470-cal-2001-form 1-1.1.pdf

470-cal-2001-form 1.pdf

470-cal-2001-form 18.pdf

470-cal-2001-form 2-1.1.pdf

470-cal-2001-form 2.pdf

470-cal-2001-form 3.pdf

470-CAL-2001-GRANTED-ABSTRACT.pdf

470-CAL-2001-GRANTED-CLAIMS.pdf

470-CAL-2001-GRANTED-DESCRIPTION (COMPLETE).pdf

470-CAL-2001-GRANTED-FORM 1.pdf

470-CAL-2001-GRANTED-FORM 2.pdf

470-CAL-2001-GRANTED-LETTER PATENT.pdf

470-CAL-2001-GRANTED-SPECIFICATION.pdf

470-CAL-2001-OTHERS.pdf

470-CAL-2001-PA.pdf

470-cal-2001-petition under rule 137.pdf

470-cal-2001-reply to examination report.pdf

470-cal-2001-specification.pdf

« Previous Patent

Next Patent »

Patent Number

254094

Indian Patent Application Number

470/CAL/2001

PG Journal Number

38/2012

Publication Date

21-Sep-2012

Grant Date

18-Sep-2012

Date of Filing

23-Aug-2001

Name of Patentee

DR. N. S. FOX

Applicant Address

4635 RIVEREDGE COVE, LITHONIA, GA 30058 UNITED STATES OF AMERICA

Inventors:

#	Inventor's Name	Inventor's Address
1	DR. K. K. MOZA	C/O. SIMPLEX CONCRETE PILES (INDIA) LIMITED, 12/1, NELLIE SENGUPTA SARANI CALCUTTA 700 087

PCT International Classification Number

E01D 22/00

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1			NA