U.S. patent number 3,808,822 [Application Number 05/280,087] was granted by the patent office on 1974-05-07 for process and system for increasing load-bearing capacity of soil.
This patent grant is currently assigned to Bolt Associates, Inc.. Invention is credited to Stephen V. Chelminski.
United States Patent |
3,808,822 |
Chelminski |
May 7, 1974 |
**Please see images for:
( Certificate of Correction ) ** |
PROCESS AND SYSTEM FOR INCREASING LOAD-BEARING CAPACITY OF SOIL
Abstract
Improved air gun energy source adapted to be submersible in
water, sand, gravel, soil, marshland, concrete slurry or the like
for repeatedly suddenly discharging pressurized air into the
surrounding material including means providing a flushing venting
of pressurized air from the operating cylinder into the release
cylinder during the time when the operating piston is unseated from
its stop to prevent the entry of grit into the release cylinder
when the discharge port is opened by the release piston. The
flushing venting air flow is shown passing around the release
piston.
Inventors: |
Chelminski; Stephen V. (West
Redding, CT) |
Assignee: |
Bolt Associates, Inc. (Norwalk,
CT)
|
Family
ID: |
26829919 |
Appl.
No.: |
05/280,087 |
Filed: |
August 14, 1972 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
|
131919 |
Apr 7, 1971 |
3707848 |
Jan 2, 1973 |
|
|
Current U.S.
Class: |
405/271; 181/119;
222/195; 239/291; 261/65; 405/248 |
Current CPC
Class: |
E02D
5/385 (20130101); E02D 15/04 (20130101); E02D
3/106 (20130101); E02D 3/103 (20130101); G01V
1/137 (20130101) |
Current International
Class: |
E02D
5/34 (20060101); E02D 3/10 (20060101); E02D
5/38 (20060101); E02D 15/04 (20060101); E02D
3/00 (20060101); E02D 15/00 (20060101); G01V
1/137 (20060101); G01V 1/02 (20060101); E02d
003/10 (); G10k 011/00 (); F15b 015/22 () |
Field of
Search: |
;61/63 ;181/.5H ;15/405
;261/65 ;222/195 ;239/291 ;116/27 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Shapiro; Jacob
Attorney, Agent or Firm: Bryan, Parmelee, Johnson &
Bollinger
Parent Case Text
This application is a division of application Ser. No. 131,919,
filed Apr. 7, 1971, and which issued as U.S. Pat. No. 3,707,848 on
Jan. 2, 1973.
Claims
I claim:
1. In an air gun energy source adapted to be submersible in
material such as water, mud, sand, gravel, soil, marshland,
concrete slurry or the like having a discharge port and also having
release means, said release means being movable between a closed
position in which the discharge port is blocked by said release
means and an open position in which the discharge port is open for
releasing pressurized air from the source through the discharge
port into the surrounding material, the improvement comprising the
inclusion of means for providing a flushing venting of pressurized
air about the release means and flowing toward the port to prevent
the material surrounding the submerged source from working its way
into the source and release means moving parts, in which the
release means comprises a piston having a shaft, said shaft passing
through a bore opening in a wall between a plurality of chambers
for containing a charge of pressurized air in the energy source,
said shaft being positioned in said opening such that a small
passage is provided between the shaft and the bore opening whereby
pressurized air from one of the chambers is permitted to pass
through said passage to provide an air bleed around the release
member and out of the discharge port when the release means is in
its open position, in which the clearance is formed by providing a
plurality of axially extending vent channels in the inside surface
of the bore around said shaft.
2. In an air gun energy source adapted to be submersible in
material such as water, mud, sand, gravel, marshland, soil,
concrete slurry or the like and having a discharge port and also
having release means, said release means being movable between a
closed position in which the discharge port is blocked by said
release means and an open position in which the discharge port is
open for releasing pressurized air from the source through the
discharge port into the surrounding material, the improvement
comprising the inclusion of means for providing a flushing venting
of pressurized air about the release means and flowing toward the
port to prevent the material surrounding the submerged source from
working its way into the source and release means moving parts, in
which the release means comprise a piston having a shaft passing
through a bore opening in a retainer wall means located between a
plurality of chambers for containing a charge of pressurized air in
the energy source, said retainer wall means containing a plurality
of vent passages therein extending between the two chambers to
provide a continuous air bleed around the release member and out
the discharge port when the release member is in its open
position.
3. In a gas gun energy source adapted to be submersible in material
such as water, mud, sand, gravel, soil, concrete, slurry, and the
like, and having a discharge port and also having release piston
means, said release piston means being movable between a closed
position in which the discharge port is blocked by said release
piston for containing a charge of pressurized gas in the source and
an open position in which the discharge port is open for suddenly
releasing pressurized gas from a pressure release chamber in said
source through the discharge port into the surrounding material,
the improvement comprising the inclusion of means for providing a
gas bleed around the perimeter of said release piston and out
through the discharge port when the release piston is in its open
position whereby any of the material surrounding the submerged
source is prevented from entering the port and working its way into
the energy source moving parts.
4. In a gas gun energy source for abruptly releasing pressurized
fluid such as air or gas or the like, and adapted to be submerged
in environmental material such as water, mud, sand, gravel, soil,
liquid concrete mix and the like, and having at least one discharge
port with a release piston located in a release cylinder suddenly
movable in said release cylinder between a closed position in which
said release piston blocks said port and an open position in which
said port is suddenly unblocked for suddenly releasing the
pressurized fluid through said port, said gas gun also having an
operating piston connected by a piston shaft to said release
piston, said operating piston being located in an operating
cylinder and engaging a firing seal when said release piston is in
its closed position, and said gas gun having a firing chamber which
is separated from said operating cylinder when said operating
piston engages said firing seal, the improvement comprising means
defining a passage extending from said firing chamber into said
release cylinder, said passage communicating with said release
cylinder on the opposite side of said release piston from said
port, whereby upon firing of said gas gun, pressurized fluid flows
from said firing chamber into said release clinder and around the
perimeter of said release piston and out through said port for
inhibiting the entry of such environmental material through said
port.
5. In a gas gun energy source for abruptly releasing pressurized
fluid as claimed in claim 27, the further improvement comprising a
gland surrounding said piston shaft and defining said passage
extending from said firing chamber into said release cylinder.
6. In an air gun energy source adapted to be submersible in
surrounding material such as water, sand, gravel, soil, marshland,
concrete slurry, or the like, for repeatedly abruptly releasing
pressurized air into the surrounding material, and having a
discharge port and also having a movable shuttle therein including
a pressurized air release piston and an operating piston with a
shaft interconnecting said pistons, said release piston being
movable in a release cylinder between a closed position in which
the discharge port is blocked by the release piston and an open
position in which the discharge port is opened by the release
piston, said operating piston being movable in an operating
cylinder to a seated position in which the operating piston is
seated against a stop for holding the release piston in its closed
position and being movable to an unseated position in which the
operating piston is spaced from the stop for moving the release
piston to its open position for abruptly releasing pressurized air
from the source through the discharge port into the surrounding
material and said operating piston being movable in said operating
cylinder back to its seated position for returning the release
piston to its closed position, the invention comprising means
providing a venting passage from said stop extending into said
release cylinder for providing a flushing venting of pressurized
air from said operating cylinder into said release cylinder during
the time when the operating piston is unseated from said stop to
prevent the entry of grit into the release cylinder when the
discharge port is opened by said release piston.
7. In an air gun energy source adapted to be submersible in
surrounding material such as water, sand, gravel, soil, marshland,
concrete slurry, or the like, the invention as claimed in claim 6,
in which said shaft interconnecting said release piston and said
operating piston passes through a bore opening in wall means
positioned between said release cylinder and said operating
cylinder, said means providing a venting passage being an enlarged
bore in said wall means defining a communicating space between said
release cylinder and said operating cylinder when said operating
piston moves away from said stop.
8. In an air gun energy source adapted to be submersible in
surrounding material such as water, sand, gravel, soil, marshland,
concrete slurry, or the like, the invention as claimed in claim 7,
in which said bore in said wall means has a diameter several
thousandths of an inch larger than said shaft.
Description
The present invention relates to an improved air gun energy source
submersible in water, sand, gravel, soil, marshland, concrete
slurry and the like.
In many areas of the world, the construction of buildings and other
structures must be carried out in places where the soil is not firm
enough to support the weight of the intended structure. For
instance, marshland or coastal land where the ground is soft are
examples of locations where this problem is often encountered.
In many of these locations having unfirm soil conditions, it is
sufficient to drive piles down into the ground beneath the place
where the structure is to be erected. The pile is driven down until
the cumulative friction along the length of the inserted pile is
sufficient to enable it to support its share of the structural
load. Alternatively, the piles may be driven until they hit a layer
of earth, or of rock, which in itself is firm enough to support the
intended structure, providing that enough of the piles can be
driven down until they reach engagement with such a firm layer.
There are, however, a number of places or conditions where piles
alone are not suitable to support the intended structure and,
therefore, it is necessary to improve the load-bearing ability of
the soil beneath the site where the structure is to be built.
In use of the invention, in one of its aspects, a densely compacted
column of granular material, for example, such as sand or gravel,
is produced extending down into the soil to the desired depth. A
number of these densely compacted granular material columns are
produced beneath the site for the intended construction project.
These columns serve to stabilize the soil, and they provide a
load-bearing capability for supporting the structure to be
built.
For producing each column of compacted granular material, a long
hollow tubular member, such as a hollow steel pipe, having a
diameter, for example, from about siz inches up to about five feet,
is positioned in the soil such that the lower end of the hollow
member is approximately at the depth at which the lower end of the
load-bearing granular material column is to be located. Then, the
granular material is fed down through the hollow member toward its
lower end, and pressurized air is abruptly released near the lower
end of the hollow member to produce a powerful impulse which can be
repeated as often as desired by the operator. These repeated
powerful impulses of the abruptly released pressurized air impel
the granular material outwardly from the lower end of the hollow
member into the surrounding region in the soil.
When sufficient granular material has been distributed and
compacted in this first region, the hollow member is withdrawn an
increment of distance, for example, such as one to four feet to
re-position its lower end a short distance above its original
position. Additional granular material is then fed down through the
hollow member, and the powerful impulses of abruptly released
pressurized air are repeated for impelling the additional granular
material outwardly into a second region in the soil above and
adjacent to the original granular material. When sufficient
granular material has been distributed and compacted into the
second region, the hollow member is again withdrawn an increment,
and the steps are repeated to produce a column of compacted
granular material of the desired height extending from the first
region upwardly toward the surface of the earth.
A plurality of these columns of compacted granular material are
produced by this process, and they collectively provide a greatly
enhanced load-bearing capability for the site involved.
In use of the present invention, in another of its aspects,
granular material is compacted at the lower end of the desired
load-bearing column, in the soil, and then poured concrete is
impelled outwardly by the repeated impulses of abruptly released
pressurized air from an air gun in a region immediately above the
compacted granular material to create a mass of concrete resting
upon the compacted granular material. After sufficient poured
concrete has been distributed to provide a footing, the lower end
of the hollow member may be left inserted down into the poured
concrete, so as to create a hollow pile embedded in a concrete
footing. If desired, the interior of the hollow member can also be
filled with poured concrete to any desired depth so as to create a
steel encased solid concrete pile.
In accordance with the present invention, in yet another of its
aspects, a system is provided in which a novel air gun energy
source adapted to be operated while inserted into the soil is
connected to the lower end of a long string of piping. This string
of piping has a smaller diameter than the hollow member such that
the string can be inserted down into the hollow member to form a
removable inner pipe assembly. The hose line to supply highly
pressurized air and the electrical "firing" line for the air gun
extend down to the air gun through the bore of the inner pipe
assembly. The air gun is "fired" repeatedly as desired to produce
powerful impulses for distributing and compacting granular
material, poured concrete and the like. In addition, the powerful
impulses from the air gun can be used to advantage to facilitate
the initial insertion of the hollow member in the soil. This
insertion is accomplished by flowing water down through the hollow
member and repeatedly firing the air gun to impel outwardly the
soil, thus removing the soil from below the lower end while
compacting the soil in a generally cylindrical region spaced around
the outside of the hollow member. By virtue of this radial
compaction effect, the soil is enhanced in its ability to provide
lateral support for the load-bearing column to be produced.
Columns of more coarsely granular material may be produced in the
soil to enable the ground water to percolate up out of the soil to
the surface through these columns. The ground water is released by
the intense impulses created by the repeated firing of the air gun.
By virtue of the compaction of the surrounding soil, the
load-bearing ability of the surrounding soil is increased.
The various objects, aspects and advantages of the improved
submersible air gun energy source for producing load-bearing
columns in the soil of the present invention will, in part, be
pointed out and, in part, will become more fully understood from a
consideration of the following detailed specification when taken in
conjunction with the accompanying drawings, in which:
FIG. 1 is an elevational view illustrating the process and system
using the present invention for producing load-bearing columns in
the soil. A portion of FIG. 1 is shown in cross section. For
clarity of illustration, that part of FIG. 1 which is directly
associated with the soil is shown greatly enlarged as compared with
the crane and associated equipment which is located above ground
level. The hollow member is shown in its initial position in FIG.
1, and a removable inner pipe assembly is shown positioned within
the hollow member, with an air gun located at the lower end of the
inner pipe assembly for generating powerful impulses by abruptly
releasing pressurized air from the air gun;
FIG. 2 is similar to FIG. 1, but it shows an intermediate stage in
the sequence of steps, with the load-bearing column having been
partially produced, and with the hollow member having been raised
to a position substantially above its initial position. Also, FIG.
2 shows more details of the automatic loader and conveyor mechanism
for continuously introducing the granular material into the upper
end of the hollow member;
FIG. 3 is an illustration generally similar to FIG. 1, but FIG. 3
shows a composite load-bearing column being produced in which the
lower end is compacted granular material, and poured concrete is
being impelled outwardly and compacted immediately above the bed of
granular material;
FIG. 4 is similar to FIG. 3 and shows a later stage in the
production of a composite load-bearing column. The removable
interior pipe assembly with the air gun at its lower end has been
removed from the hollow member, and the hollow member has been
filled with concrete, so as to reinforce the hollow member, forming
an encased solid concrete column;
FIG. 5 shows the adapter assembly and loading unit at the upper end
of the hollow member in which the granular material and/or poured
concrete can be introduced and also showing the upper end of the
removable interior pipe assembly;
FIG. 6 shows the inner pipe assembly on enlarged scale. Portions of
FIG. 6 are in section to show the electrical control cable and the
high-pressure hose and their connections for supplying the
pressurized air to the air gun at the lower end of the inner pipe
assembly;
FIG. 7 is a top plan view of the upper end of the inner pipe
assembly, this view being taken along the plane 7--7 in FIG. 6,
looking downwardly;
FIG. 8 is a longitudinal sectional view of the air gun and lower
end of the inner pipe assembly;
FIG. 9 is a cross section taken along the line 9--9 in FIG. 8;
FIG. 10 is a cross section similar to FIG. 9 showing a modified
embodiment; and
FIG. 11 is a cross section similar to FIGS. 9 and 10 showing
another embodiment.
As shown in FIG. 1 of the drawings, when it is desired to increase
the support capability of the soil 18 by producing a load-bearing
column of granular material, such as shown dotted at 20, a hollow
tubular member 22 is inserted down into the soil. This hollow
member 22 is usually a length of steel pipe having a diameter, for
example, from about six inches up to about five feet. The hollow
member 22 may have any desired length from about 10 feet up to more
than 100 feet, depending upon the conditions and characteristics of
the soil 18 and depending upon the weight and size of structure
intended to be supported by the column 20 and by other similar
nearby columns (not shown) to be produced in the soil 18.
Removably positioned within this hollow member 22 is an inner pipe
assembly 24, having an air gun energy source 30 secured to its
lower end, as shown in greater detail in FIG. 6. The inner pipe
assembly 24 includes a lower pipe section 26-L, an upper pipe
section 26-U, and between these two pipe sections 26-L and 26-U is
an intermediate pipe section 26-I having a length such that the
total length of the entire assembly 24 is commensurate with the
desired length of the hollow member 22. The lower and intermediate
pipe sections 26-L and 26-I are releasably coupled together by a
lower pipe coupling 27, which is threaded onto the lower and
intermediate pipe sections and is permanently welded to the lower
section by a weld at 31. Similarly, the upper pipe section 26-U and
intermediate section 26-I are coupled together by an upper pipe
coupling 28, which is threaded onto both the upper and intermediate
pipe sections and is permanently welded to the upper one by a weld
at 32. In this way, the inner pipe assembly 24 can conveniently be
disassembled by unscrewing the intermediate pipe 26-I to be
replaced by a shorter or longer pipe section as required by the
particular job site.
To the lower end of the inner pipe assembly 24 is secured a novel
soil-submergence air gun 30 which is supplied with pressurized air
through a high pressure hose line 34 (FIG. 6) and is controlled by
electrical signals through wires located within an insulated
electrical cable 36 extending within the pipe sections 26.
As an alternative to firing the air gun in response to an
electrical signal, it can be arranged to be automatically
self-firing, for example, to fire every so many seconds. Electrical
firing apparatus for an air gun and also arrangements for making
the air gun automatically self-firing at intervals are disclosed in
U.S. Pat. No. 3,379,273 which issued Apr. 23, 1968.
A convenient manner of inserting the hollow member 22 into the soil
18 is to pump a jetting flow of water downwardly through the
annular space 38 (FIG. 1) surrounding the inner pipe assembly 24.
This flow of water is provided by a pump 40 (FIG. 1) driven by an
engine 42 with an in-take line 44 extending from the pump 40 over
to a suitable nearby source of water, shown as a body of water 46.
The water is drawn into the line 44 through a strainer 47 to
prevent sand and grit from entering the pump 40. A control valve 48
can be used, if desired, to regulate the flow through a jetting
water supply line 49 connected into the head adapter unit 50 (FIG.
5) which is attached to the upper end of the hollow member 22.
In order to produce a forceful downward flow of water in the
annular space 38 (FIG. 1), is indicated by the flow arrows 51 in
FIG. 5, the upper end of the head adapter unit 50 is temporarily
shut off by a manually operable valve mechanism 52 containing a
plurality of large ports 54 which can be closed by means of a
movable disc 53 which can be turned relative to a fixed disc 55, so
that ports in both discs align or not. The movable disc is operated
by a control handle 56. With the ports 54 closed, the water being
supplied through the line 49 is forced down through the annular
space 38, so as to issue with a jetting action from the lower end
58 (FIG. 1) of the hollow member 22. In this way the jetting water
action in the vicinity of the lower end 58 dislodges and erodes the
soil, so as to aid in inserting the hollow member 22 down into the
earth.
As the emplacement of the hollow member 22 is being carried out, it
is sometimes advantageous to "fire" the air gun 30 from time to
time. The result of firing the air gun 30 is that pressurized air
is abruptly released in all directions simultaneously through its
multiple discharge ports 60 (FIG. 6) serving to forcefully impel
the soil away from the lower end 58, thus enhancing the ability of
the entire assembly to penetrate down into the earth. Also, the
radial compaction of the surrounding soil enhances its load-bearing
ability.
Among the advantages of using the water jetting action aided by
repeated firing of the air gun 30 to emplace the hollow member 22
into the earth, is that the method utilizes components of the same
system of equipment which will be used to produce the load-bearing
column 20.
An alternative way in which the hollow member 22 can be positioned
into the earth is to drive it down by a pile driver, with the inner
pipe assembly 24 having been removed before the hollow member 22 is
driven down. Then after the hollow member 22 is in place, a water
jet pipe (not shown) is pushed down through the interior of the
hollow member 22 to flush out any soil material within the member
22. Then, this water jet pipe is removed, and thereafter, the inner
pipe assembly 24 is lowered into position within the hollow member
22. The spacing struts 64 (FIG. 1) near its lower end serve to keep
the inner pipe assembly 24 centrally positioned, in concentric
relationship within the hollow member 22. As shown in FIG. 5, there
are radial struts 65 which interconnect the upper pipe section 26-U
to the head adapter unit 50. There are multiple large set screws 62
which releasably secure the unit 50 to the upper end of the hollow
member 22 after the inner pipe assembly has been lowered into
position.
In order to raise or lower the hollow member 22 or the inner pipe
assembly 24, an operating and control vehicle 66 is provided having
a crane mechanism 68 with a lifting cable 69 attached to a sling
chain 70 (FIG. 5) secured to the upper end of the head adapter unit
50. A similar sling chain 71 (FIG. 5) is secured to a connector
assembly 72 at the upper end of the inner pipe assembly 44.
The vehicle 66 also includes a high pressure air supply 74
including multiple stage air compressor and a suitable tank or
receiver for storing the compressed air produced. This compressed
air may be stored at any suitable pressure from approximately 500
to approximately 3,000 pounds per square inch, depending upon the
desired operating pressure for the air gun 30. At the output from
the high pressure air source 74 is an adjustable
pressure-regulating valve (not shown) and a shut-off valve 76
connected to the high pressure hose line 34. Also, contained on the
vehicle 66 is an electrical control circuit (not shown) which
produces the signal that is sent through the cable 36 (FIG. 6)
whenever it is desired to fire the air gun 30. There is a solenoid
operated valve 78 (FIG. 6) mounted upon the air gun 30 and
connected to the electrical cable 36 which is actuated by the
electrical firing signal and serves to trigger the firing of the
air gun.
This solenoid valve 78 is described in detail and claimed in the
copending patent application of Anthony J. Delano and myself, Ser.
No. 855,667, filed Sept. 5, 1969.
After the hollow member 22 and inner pipe assembly 24 are
positioned as far down in the soil 18 as desired, it is sometimes
desirable to create a cavity about the lower end 58 because this
cavity is sometimes helpful to facilitate the initial stages of
introduction of the granular material into the soil. Such a cavity
may be initially generated in the soil in the region surrounding
the lower end 58 by providing a flow 51 (FIG. 5) of water down
through the annular space 38 with the large ports 54 closed and by
repeatedly firing the air gun 30 while the water flow is occurring.
These interacting steps compact the soil in the region of the
bottom end 58 and create a cavity by flushing out the loose,
light-weight and fine material there.
The steps which are carried out when it is desired to produce the
load-bearing column 20 of granular material are as follows:
In order to start producing this load-bearing column 20, the water
flow 51 is stopped, the firing of the air gun 30 is stopped, and
the large ports 54 are opened. The desired granular material 82 is
now fed into the hopper funnel 80 (FIG. 5) on the head adapter
unit, so as to feed down through the ports 54 and down through the
annular space 38 into the region near the lower end 58 of the
hollow member 22.
The firing of the air gun 30 is now carried out repeatedly to
forcefully impel the granular material 82 outwardly and distribute
it in the initial region 84 at the lower end of the desired column
20, as shown in FIG. 1, while compacting it and the soil 18 about
the region 84 being filled by the granular material 82.
The granular material 82 is now fed as needed into the hopper
funnel 80 (FIG. 5) by means of a conveyor belt 86 (FIG. 2) having a
sequence of upstanding slats 87 at spaced intervals along the belt
86 to prevent the material 82 from sliding back down. The belt 86
is supported by a plurality of rollers 88 mounted upon a boom truss
90. The upper end of this truss 90 is removably pivotally connected
at 91 to the head adapter unit 50. Its lower end is removably
pivotally connected at 92 to the chassis of a loader cart 94 (FIG.
2) having a large hopper 95 with an outlet 96 which continuously
supplies the granular material 82 to the conveyor belt 86. The
desired type of granular material 82, such as sand, gravel, crushed
stone, small rocks, or the like, is dumped into the hopper 95. The
loader cart 94 has wheels so that when the hollow member is
withdrawn by increments from the earth, as shown in FIG. 2, and the
truss 90 and conveyor 86 incline upwardly, the cart 94 rolls over
toward the member 22 a distance to accommodate the changing
inclination of the truss 90 and conveyor 86.
The repeated firing of the air gun 30 serves to distribute and
compact the granular material 82 and the surrounding soil 18 in the
initial region 84, as discussed above. The annular space 38 is now
full of the granular material, advantageously providing a dense
heavy weight in the nature of a "hydrostatic" head bearing down
upon the material in the region 84 being compacted. The repeated
firing of the air gun 30 shakes the hollow member 22, and causes
the material 82 in the annular space 38 to shake and to slump and
to continue to feed downwardly. Water can be fed into the annular
space 38 from the supply line 49, if desired, to facilitate the
downward feeding of the material in the annular space 38.
After suitable amount of the granular material has been compacted
into the initial region 84, the hollow member 22 is withdrawn an
increment of distance, for example, such as from one to four feet
to reposition the lower end 58 a short distance above its initial
position, which was as shown in FIG. 1.
An advantageous way to determine when a suitable amount of the
granular material 82 has been compacted into the initial region 84
is to observe the rate at which the material 82 has been feeding
down through the hopper funnel 80. When this feed rate has slowed
to an insignificant amount, it means that the initial region 84 has
become so fully loaded and compacted with the granular material 82
that it is refusing to accept any more. Accordingly, the hollow
member 22 and the inner pipe assembly 24 with the air gun 30 are
now raised the increment distance discussed above to reposition its
lower end 58.
The repeated firing of the air gun 30 abruptly releasing powerful
impulses of high pressure air in its re-positioned location impels
additional granular material outwardly into a second region 98
indicated dotted in FIG. 1 surrounding the re-positioned end 58, so
that this additional material 82 is adjacent to and above the
material in the initial region 84.
When sufficient granular material has been distributed and
compacted into this second region 98, the hollow member 22, inner
pipe assembly 24, and air gun 30 are raised another increment of
distance and the steps are repeated, as above described, to produce
the load-bearing column 20.
FIG. 2 shows an intermediate stage in the process in which the
column 20 is approximately one-half completed.
It is to be noted that the repeated forceful impulses produced by
the repeated firing of the air gun 30 are capable of impelling the
granular material 82 outwardly so as to produce a load-bearing
column 20 which is advantageously at least three times the diameter
of the hollow member 22. In the illustrative embodiment shown in
FIGS. 1 and 2, the column 30 is more than four times the diameter
of the hollow member 22.
Among the advantages of being able to create such relatively large
diameter columns 20 is that they have greater load-bearing
strength, and fewer of them are required to be produced in the soil
to support a given structure, thus saving greatly in time and
labor.
In the process shown in FIGS. 3 and 4, a composite column 20A in
the soil is created including a base B of compacted granular
material, a footing F of concrete and a pipe pile P which is
reinforced by filling it with concrete. The compacted granular
material 82 forming the base B in the initial region 84 is produced
by the sequence of steps as described above.
When sufficient granular material has been introduced into the base
B, the feed of granular material 82 is stopped. The hollow member
22, inner pipe assembly 24, and air gun 30 are raised an increment
of distance to reposition the lower end 58, and concrete is not
introduced into the hopper funnel 80. This concrete can be fed by
the substantially horizontal conveyor belt 86 (FIG. 3) if desired
or it can be pumped through a hose (not shown) into the hopper
funnel 80, or can be fed directly from a concrete mixture supply
truck via a chute into the hopper funnel.
The air gun 30 is repeatedly fired during the feeding of the
concrete to form the footing F. In this way the concrete is
impelled outwardly and compacted into a footing F in a region 98
immediately above the material 82 in the base B.
If it is desired to enlarge the depth of the footing F, the
components 22, 24 and 30 are simultaneously raised another
increment of distance and additional concrete is fed down while the
air gun 30 is repeatedly fired.
After sufficient concrete has been introduced into the footing F,
the inner pipe assembly 24, with the air gun 30, and the head
adapter 50, are removed to leave the hollow member alone, as shown
in FIG. 4. The lower end 58 of this member extends down into the
footing F to provide a strong pipe pile member 22.
If it is desired to reinforce this pipe pile member 22, then as
shown in FIG. 4, it is filled with concrete to form a steel encased
solid concrete pile. Reinforcing rods may also be used.
The concrete 100 is shown being poured down a chute 101 from a
concrete mixture supply truck 102.
As shown in FIG. 6, the inner pipe assembly 24 includes a mounting
section 103 welded to the lower end of the lower pipe section 26-L.
The air gun 30 has a mounting flange 104 which is removably
fastened by machine screws 105 to this mounting section 103.
At the upper end of the upper pipe section 26-U is secured another
mounting section 106 to which a split retainer 108, 109 (FIG. 7) of
the connection assembly 72 is removably secured by machine screws
110.
The high pressure air hose line 34 and the electrical cable 36
extend through channels in the split retainer 108, 109. As shown in
FIGS. 6 and 7, stiff flexible protective sleeves 111 and 112
surround the hose 34 and cable 36, respectively, in the region
where they pass through the split retainer 108, 109. The two halves
108 and 109 of the split retainer are held clamped firmly about
these sleeves 111 and 112 by means of clamp screws 114. A support
ring 116 is secured to the split retainer 108, 109 by means of
machine screws 117, and the sling chain 71 is attached to this ring
116.
Thus, the length of the inner pipe assembly can be changed by
disassembling the connector assembly 72 including the split
retainer 108, 109 so as to be able to remove the hose 34 and cable
36 from within the pipe sections 26-U and 26-I. Then, a longer or
shorter intermediate pipe section 26-I can be inserted as mentioned
above, and the components of the inner pipe assembly 24 be
reassembled in readiness for use.
From the foregoing description, it will be appreciated that the air
gun 30 is being operated in an extremely hostile and abrasive
environment, for it is surrounded by water, soil, mud, granular
material, such as sand or gravel, a concrete slurry, and the like.
In order to enable the air gun 30 to operate advantageously and to
continue reliable operations for thousands of "shots" without
failure under these difficult circumstances, it incorporates
certain novel improvements over the air guns disclosed in U.S. Pat.
No. 3,379,273, mentioned above. Before discussing these
improvements, as shown in FIGS. 8, 9, 10 and 11, which are claimed
herein, it may be helpful to the reader to review briefly the
operation of the air gun 30, as shown.
When the shuttle 120 (FIG. 8) is in its normal position prior to
"firing" the lower lip 122 of the skirt 124 on the pressurized air
releasing piston 126 is in sealing engagement with a movable seal
ring 128 so as to hold a charge of pressurized air in a charge
chamber 130. A plurality of seal springs 132 held in a retainer 133
urge the movable seal ring 128 against the rim 122. Thus, the
pressurized air is held against going out through the ports 60.
A releasing cylinder sleeve 134 defines a release cylinder 135 and
surrounds the release piston 126. The sleeve 134 has ports 136
aligned with the ports 60 in the air gun body 138. A seal between
the movable seal ring 128 and the cylinder sleeve 134 is provided
by an O-ring 140. A retainer 142 holds the O-ring 140 and also
holds another O-ring 144 providing a seal between the cylinder
sleeve 134 and the body 138.
In preparation for firing, air under pressure is introduced through
a hose line connection fitting 146 from the hose line 34 shown in
FIGS. 6 and through a passage 148 in the upper housing 149 into an
operating cylinder 150 lined with an operating cylinder sleeve 152.
The pressurized air enters the chamber 130 by flowing down through
a constriction 153 and through an axial passage 154 in the hollow
piston shaft 156, which interconnects the release piston 126 with
an operating piston 158. The operating piston 158 is sealed to the
hollow piston shaft 156 by an O-ring 160 and is held by a nut
162.
As the pressurized air flow into the cylinder 150, the constriction
153 briefly maintains the pressure in cylinder 150 above the
pressure in the chamber 130, assuring that the rim of the operating
piston 158 remains firmly seated against a firing seal O-ring 164.
The seal 164 is held by a retainer and shuttle stop member 166
which also holds a shaft gland 168 in an annular socket 170.
Another retainer annulus 172 retains the shaft gland 168 in the
socket 170. The stop member 166 has a raised stop surface 167 which
engages the lower face of the piston 158.
After the chamber 130 is filled to the desired pressure, than the
air gun 30 is ready to be fired. This may be accomplished by making
the air gun self-firing, as explained above, in which case the
solenoid valve 78 and firing cable 36 can be omitted. The firing
passages 173, 174, 175, 176 also can be omitted when the air gun is
made self-firing. To make the air gun self-firing, the effective
area of the air releasing piston 126 exposed to the pressurized air
in chamber 130 is made greater than that of the operating piston
158 exposed to the pressurized air in cylinder 150. Accordingly,
when the pressure in chamber 130 has risen up substantially to that
in cylinder 150, the seal between the ring 164 and the operating
piston 158 becomes opened to allow the high pressure air in chamber
150 to communicate with the lower face of piston 158, and the
shuttle 120 is accelerated away from the seal 164 and from seal
ring 128 and abruptly opens the ports 60 to suddenly release the
pressurized air providing a powerful impulse. The by-pass passages
180 in the cylinder sleeve 152 allow free communication for air to
pass from chamber 150 into the space beneath the travelling piston
158. The time intervals between "shots" when the air gun is
self-firing is controlled by the constriction 153. The greater the
constrictive effect, i.e. the smaller the diameter of the passage
153, the longer the interval between shots, and vice versa.
Alternatively, the valve 78 can be used. When it is activated by an
electrical signal through the cable 136, the pressurized air passes
through firing passages 173, 174, 175 and 176 and into an annular
firing chamber 178 on the opposite side of the operating piston 158
from the operating cylinder 150. The application of pressure to the
chamber 178 tends to equalize pressure exerted on opposite faces of
the piston 158 to allow the shuttle 120 to accelerate away from the
seal 164 and seal ring 128, thus suddenly opening the ports 60 to
abruptly release the pressurized air from the chamber 130. The
passage 176 and the annular firing chamber 178 are formed in the
retainer and stop member 166. There are by-pass passages 180 formed
by cut outs in the operating cylinder sleeve 152 which serve to aid
in equalizing the pressure on opposite faces of the operating
piston 158 after it has begun accelerating away from the firing
seal 164.
After firing, the air remaining trapped in the operating cylinder
150 above the by-pass passages 180 is compressed by the
fast-travelling operating piston 158 thus serving to decelerate the
shuttle 120 and then to return it to its initial position.
With respect to the novel improvements incorporated in the air gun
30 for operation when embedded in soil under the difficult
environmental conditions, as described above, these improvements
are included regardless of whether the air gun is made self firing
or not.
To prevent any fine grit from working past the peripheral piston
portion 182 so as to enter the release cylinder 135, there is an
advantageous pneumatic flushing venting action which has been
provided in the air gun 30. This flushing venting action is
provided by the small clearance passage 186 (FIGS. 8 and 9)
provided between the shaft gland 168 and the hollow shuttle shaft
156. The inside diameter (I.D.) of the gland 168 is several
thousandths of an inch larger than the outside diameter (O.D.) of
the shaft 156. Also, the I.D. of the retainer and stop member 166
and of the annulus 172 are correspondingly larger than the O.D. of
the shaft 156.
Thus, as soon as the operating piston 158 has accelerated away from
the stop surface 167, the pressurized air in the firing chamber 178
and in the cylinder 150 beneath the piston 158 rushes over the
raised stop surface 167. Some of the pressurized air rushes down
through the vent passage 186 and into the release cylinder. The
result is to pressurize the release cylinder 135 so that there is a
continuous bleeding 188 of pressurized air down along the outside
surface of the enlarged peripheral portion 182 of the release
piston 126 and out through the ports 60, during the time while the
shuttle 120 is in motion upward and continuing until it has been
returned down into position against the seal 164. This continuous
air bleed 188 is a barrier to prevent the entry of any grit into
the release cylinder 135 during shuttle motion. If any fine grit
should find its way into the release cylinder 135, the air bleed
188 would soon flush out the grit.
The bleed 188 becomes very rapid when the release piston 126 is
travelling up toward the retainer annulus 172 during firing of the
air gun, which travel causes compression of the air trapped in the
release cylinder 135.
Another advantage of the vent passage 186 is that it allows the
escape of pressurized air from beneath the operating piston 158 as
it is moving back toward the seal 164. This venting assists in
assuring a rapid re-seating of the operating piston 158 against the
firing seal 164.
FIG. 10 shows an alternative embodiment of the vent passage.
Instead of an annular vent passage 186, as shown in FIG. 9, there
are a plurality of axially extending vent channels 186A formed in
the inside surface of the shaft gland 168.
FIG. 11 shows a further embodiment of the vent passage. A plurality
of vent passages 186B are drilled down through the retainer and
stop member 166 and down through the gland 168 and also down
through the retainer annulus 172. These vent passages 186B are
located so that they extend down within the raised stop surface
167. Thus, air cannot vent from the region beneath the piston 158
down through the passages 186B until after the piston 158 has
accelerated away from the stop surface 167. Thus, the venting
action does not reduce the pressure in the firing chamber 178 at
the moment of actuation of the solenoid valve 78 to fire the air
gun.
A very small clearance space may be provided between the skirt 124
of the release piston 126 and the releasing cylinder 134
surrounding it. Thus, the inside diameter (I.D) of the releasing
cylinder sleeve 134 may be a few thousandths of an inch larger than
the outside diameter (O.D.) of the piston skirt 124. This small
clearance assures that a pneumatic flushing venting action as
provided by the clearance passages 186, 186A or 186B is also
provided around the skirt 124 to prevent fine grit from working
past the peripheral piston portion material mat rial that may work
its way into the release chamber 135 will in time be flushed out by
the air bleed 188.
The clearance between the skirt 124 and the sleeve 134 does not
affect the charge of pressurized air in the charge chamber 130
since it is maintained therein by the seal formed by engagement of
the lower lip 122 of the skirt 124 and the movable seal ring 128.
Grit is kept out of the charge chamber 130 by the sudden release of
the pressurized air through the ports 60. In the event any fine
grit should manage to get into the charge chamber 130 it will fall
to the bottom thereof and remain settled to be removed when the
chamber is disassembled for cleaning or inspection.
Where it is desired to remove or expell ground water and the like
from a depth in the soil 18 (FIGS. 1 and 2) columns 20 of coarse
granular material 82 are produced extending up at least from that
depth to the surface of the ground. These granular columns allow
the ground water to percolate up to the surface. The ground water
is released from the sub-surface soil 18 by the intense impulses
created by the repeated firing of at least one air gun 30. This air
gun is positioned at a depth below the surface corresponding
generally to the depth from which it is desired to expell the
ground water. In other words, the repeated firing of the air gun
exerts a radial pressure on the surrounding soil. This expells the
ground water and forces the water to percolate up through the
nearby columns of granular material 82. As the ground water is
released, the soil compacts around the columns 20 to increase the
load-bearing ability of the surrounding soil.
* * * * *