US3530675A - Method and means for stabilizing structural layer overlying earth materials in situ - Google Patents

Description

5 7 6m nu,I 3v. L 5 m V 30 Dn E v.. A L L M U uw.. FS C U N STR S I Sept. 29, 1970 L A. TuRzlLLO METHOD AND MEANS FOR STABILIZ EARTH MATE 2 Sheets-Sheet l Filed Aug. 26, 1968 I m 1 I m INVENTOR. Turzl lo Lee A.

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@M @and Attorrleq Sept. 29, 1970 A. TuRzlLLOl METHOD AND MEANS FOR STABILIZlNG STRUCTURAL LAYER OVERLYNG EARTH MATERIALS IN SITU 2 SheFtS-Sheet 23 Filed Aug. 26, 1968 I N VENTOR.

l I', At tomen) United States Patent O 3,530,675 METHOD AND MEANS FOR STABILIZING STRUCTURAL LAYER OVERLYING EARTH MATERIALS IN SIT U Lee A. Turzllo, 2078 Glengary Road, Bath, Ohio 44313 Filed Aug. 26, 1968, Ser. No. 755,273 Int. Cl. E02d 5 00, 17/04 U.S. Cl. 61-35 8 Claims ABSTRACT F THE DISCLOSURE BACKGROUND OF INVENTION Heretofore a number of methods and means have been available for stabilizing porous earth masses in situ. The known related methods, however, have had limited uses and/or limited results for various reasons. Some of these methods are in the class of so-called chemical grouting, in which porous earth materials, such as sandy soil, have chemicals injected into the same to make the same less migrant for excavation purposes. Other methods were utilized to force hardenable fluids into the subsoil to fill cavities, voids, and pores existing or created in the same, so that only unpredictably limited areas of the subsoil could be depended upon for any substantial degree of increased load-boaring capacity.

In one known method of treating a porous earth situs, a pilot hole was drilled several feet into the earth, and cleared of loose material as by flushing with water. After forcing pressurized air into the hole to drive out the flushing water, hardenable fluid repair material was forced into voids in the region surrounding the hole. When this repair material hardened, the process was repeated until the subsoil was similarly treated to desired depth. In other words, only originally available voids were filled with repair material to form an irregular-shaped body of rather unpredictable load-boaring capacity, and the aforesaid pilot hole, drilled to the full depth of the formed irregular-shaped body, was required to be filled with ller material by a series of additional operations. Moreover, the last-mentioned method was impractical, if not unduly expensive, for providing a solid supporting column under a footer, floor, or the like, overlying an earth situs.

SUMMARY OF INVENTION In use of the method and means of the present invention to provide a solid columnar support under a sagging concrete floor or like slab or layer over an earth situs, a hole, smaller than the diameter of the required supporting column, is drilled in said slab. A boring tool provided with an expansible agitator means is then pushed through the hole and drilled into the earth below the slab. When the agitator means clears the slab, it is expanded, so that with requisite rotation of the tool the earth is loosened and thoroughly agitated to a requisite extent below the slab, to define a generally cylindrical-shaped body of loose earth, the operation being aided by outward compaction of the soil by the rotated agitator means.

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Hydraulic self-hardenable cement mortar or chemical mortar, under pressure, is now pumped through a passage in the tool shaft to mix thoroughly with the loosened earth. Before the mortar hardens, however, the agitator means is contracted to allow removal of the boring tool through the small slab opening. Upon hardening of the mixture of mortar and earth, the cylindrical body thereof overlying the hole in the slab will support the slab, with or without elevating the slab, depending upon the requirements. The hole in the slab can be lled in with concrete if desired.

A general object of the present invention is to provide improved method and means for providing a solid columnar support under sagging licor or like slab overlying earth of a situs, without necessarily requiring use of conventional heavy drilling and pile-forming equipment, and whereby the cost of the operation will be relatively low and the need for total or substantial replacement of sagging slabs can be avoided.

Other objects of the invention will be manifest from the following brief description and the accompanying drawings.

Of the accompanying drawings:

FIG. 1 is a fragmentary vertical cross-section, partly broken away, illustrating improved means for providing solid columnar support in an earth situs, under a floor or like slab overlying earth materials of the situs'.

FIG. 2 is a horizontal cross-section taken substantially on the line 2-2 of FIG. l, but with the drilling tool apart from the situs.

FIG. 3 is a fragmentary vertical cross-section corresponding to FIG. 1, but illustrating the completed columnar support provided in the situs by the method of the invention.

FIG. 4 is a view corresponding in part to FIG. 1, but illustrating use of a modified form of earth agitating means for practicing the method of the invention, in an initial step of the method.

FIG. 5 is a View corresponding to FIG. 4, but illustrating use of the agitating means in a more advanced stage of the method.

FIG. 6 is a View corresponding to FIG. 4, but illustrating use of another form of expansible agitator means for use in the method.

FIG. 7 is a view corresponding generally to FIGS. 4 and 6 but illustrating initial step in the method for use of further modified form of agitator means.

FIG. 8 is a view corresponding to FIG. 7 but illustrating a further advanced step in the method performed by the agitator means.

Referring to FIGS. 1 and 2 of the drawings, there is illustrated suitable apparatus for practicing the method of the present invention, as for providing reinforcing support for a sagging structural layer supported by earth E of a situs, such as a concrete floor or slab F. As shown in FIG. 1, the improved apparatus may include a tool T including an elongated hollow metal shaft 10, provided with an apertured closure member 11, which may be inthe form of a drill bit of known type, releasably affixed on the inner end of the shaft, as by means of break-away pins 12. Shaft 10 may be of a single length of tubing, or of a plurality of sections thereof coupled together in known manner. In any event, the shaft 10 may be mounted for rotation in a number of Ways, such as by afiixing the shaft at its upper end to a connector 13 rotatably mounted in a carriage 14 of a known form of drilling rig (not shown), for rotation by a hydraulically, electrically, or air operable motor 15. An upward extension 13a of rotatable connector 13 may have thereon a removable swivel connector 16 communicating with suitself-hardenable cementitious material, such as chemical mortar, under pressure, The swivel connector 16 is removable from the extension 13a, for disconnecting the latter from said source, as well as for inserting reinforcing devices down the hollow shaft in practice of the method to be described later.

Suitably mounted on the lower end of the shaft 10, may be expansible and retractable agitator means 17, such as a plurality of radially outwardly curvate blades 18 pivoted at points 19 to swing between a stopped, expanded condition shown in full lines in FIGS. l and 2, and contracted condition thereof shown in chain-dotted lines in FIG. 2. In said contracted condition, the lower end of the clockwise rotating rod 10 with agitator means 17 thereon is readily insertable downwardly through the hole H in slab F, and into the earth below the slab. Reverse rotation against the earth materials, however, causes the blades to expand outwardly, and continued reverse rotation is effective to agitate and loosen the earth materials to define a cylindrical body 20 thereof of greater transverse cross-section than that of hole H, as indicated by chain-dotted lines in FIG. 1. The length or depth of body 20 is determined by the total stroke of axial movement or reciprocation of the agitator means 17 below slab F. The requisite loosening action of the earth is aided by impaction of the soil radially beyond the circular path of the ends of the blades 18.

After formation of the earth body 20, the churning action of the expanded blades 18 may be utilized to mix in fluid cementitious material, such as self-hardenable hydraulic cement or chemical mortar, pumped through swivel 16, shaft 10, and the apertured closure or drill bit 11. The pressurized fluid material may be retained below slab F by radially outward expansion of a rubber sleeve 22 against the wall of the hole H. For this purpose, the rubber sleeve 22 is retained on a metal tube 23, axially slidably mounted on shaft 10, between relatively movable and xed stop rings 24 and 25 on tube 23, respectively. A nut 26, threaded on metal tube 23, is selectively rotatable against a metal sleeve 27 on tube 23, axially to compress the rubber sleeve for said radial expansion thereof. While mixture of mortar and earth of the formed cylindrical body thereof is still iluid, the nut 26 is backed away to permit removal of the tool with agitator means 17, in collapsed condition, through the hole H.

In use of the apparatus described in connection with FIGS. 1 and 2, to form a hardened columnar support C beneath the concrete slab F, as shown in FIG. 3, the steps of the method may be as follows:

First, a hole H is drilled in the floor, slab or surface layer F, to be of smaller diameter than that of the required column to be formed under the same, then the carriage 14 of a drilling rig (not shown) is moved to pass the rotating rod 10, with the contracted agitator means 17 thereon, downwardly through the hole H, until all of the agitator means is worked within the earth beneath the slab. At this point, the rubber sleeve 27 may be expanded to seal the hole H, as shown in FIG. l, in which case the shaft 10 is freely rotatable and axially shiftable Within the now iixedly positioned metal tube 27.

Now, with the agitator means 17 so positioned in the earth E, the direction of rotation of the shaft 10 is reversed to expand the blades 18, as shown in full lines in FIGS. 1 and 2, by pressure of the earth against the concave sides of the blades. Continued rotation of the agitator means, While reciprocating the shaft 10, is effective to form a cylindrical body 20 of loosened earth to selective depth, as indicated in chain-dotted lines in FIG. 1, and generally of diameter substantially greater than the opening H in slab F. The material of the body 20 will be more loose and porous than before due to compaction of soil into the surrounding earth.

After the body 20 of substantially loose and porous earth has been formed to required depth, indicated in chain-dotted lines in FIG. 1, uid, self-hardenable cementitious material, such as hydraulic cement mortar under pressure, is pumped through the swivel connector 16, shaft 10, and apertured drill bit 11, into the loosened earth material of body 20 thereof formed by the agitator means. With continued rotation and vertical reciprocation of the expanded agitator means 17, as described above, the fluid mortar is thereby thoroughly mixed with the loosened earth materials into a fluid, self-hardenable mass. While this mass is still uid, the shaft, 10 may be elevated with the agitator means in contracted Condition thereon, to withdraw the same through the small hole H in slab F. Because the Huid is supplied under pressure, the intruded body 20 may be extended to raise and/ or level the slab F.

Prior to such withdrawal of the agitator means, however, rigid reinforcing devices, such as one or more elongated rigid reinforcing elements R, may be projected downwardly through the shaft 10 to knock out the bit or closure member 11. The swivel connector 16 is adapted to be temporarily disconnected from shaft extension 13a for this purpose, as described above. After the reinforcing device or elements R have been so positioned, the aforesaid additional pumping of uid into the intruded body 20 is accomplished if or as necessary to elevate the slab P.

Upon hardening of the concrete body 20, it forms a solid cylindrical concrete column or pile C, the upper end of which overlies or spans the hole H to provide requisite strong support for the slab F, as shown in FIG. 3. The hole H may be lled in with concrete to the upper level of the slab.

Referring to FIGS. 4 and 5, there is illustrated a modied form of agitator means 17a mounted on shaft 10, the same including a plurality of spiral elements 18a of strong spring steel wire, extended between a relatively fixed collar 30 at the lower end of shaft 10 and a relatively movable collar 31 non-rotatably carried by a sleeve 32 which is axially shiftable on shaft 10. Sleeve 32 is axially shiftable, as by manual or other means, radially to expand or contract the spiral elements 18a, as shown in FIGS. 5 and 4, respectively. That is, in the above described practice of the method of the invention, the contracted agitator 17a is insertable through hole H, and then can be expanded and rotated with the shaft 10, as shown in FIG. 5, to form a cylindrical body 20a of loose earth, as before, with or without fluid sealing the hole H. The results are otherwise substantially as described above in connection with FIG. 3.

FIG. 6 is a view corresponding to FIG. 4, but showing a modified form of agitator means 17b, wherein the spiral blades 18b are of thin, flexible strips of flat springy metal, adapted radially to expand and contract, generally as illustrated in FIGS. 5 and 4, respectively.

FIG. 7 is a view corresponding to FIG. 4, illustrating another modied form of agitator means 17c, including a tapered spiral screw S on the inner end of shaft 10, adapted to pass through hole H in olf-center relationship, progressively to pass axially staggered cutting teeth 18C, one at a time, until all of the cutting teeth are below slab F, for agitating and mixing the earth materials as before (see FIG. 5). The use is otherwise generally as for the method described above in connection with FIGS. 1, 2, and 3, the agitator means being removed through the hole H in the same progressive manner as described for insertion thereof.

In any of the methods described above the self-hardenable Huid material pumped into earth body 20 may be other than hydraulic cement mortar. For example, wellknown chemical grouts may be pumped into the earth body 20 in proportions which produce very stiff gels from dilute, properly catalyzed, aqueous solutions.

Other modifications of the invention may be resorted to without departing from the spirit thereof or the scope of the appended claims.

What is claimed is:

1. A method of providing reinforcing support for a slab or like solid outer structural layer overlying earth materials of an earth situs, comprising the steps of: projecting expansible agitator means through a hole of relatively small crossesection in said structural layer to present the agitator means inwardly of the same; operating the expanded agitator means to agitate and loosen the earth materials to define a body thereof of greater transverse cross-section than that of said hole and extending inwardly of said structural layer; pumping lluid, self-hardenable cementitious material under pressure into the loosened earth of said body to mix therewith as a composite, self-hardenable column; retracting said agitator means in contracted condition through said hole while said composite column is in iluid condition; and allowing said composite column to harden for support of said structural layer.

2. A method as in claim 1, wherein said hole is sealed against outward flow of the cementitious fluid, during said pumping thereof.

3. A method as in claim 2, the pressure of said cementitious fluid material being suiriciently great to elevate said structural layer.

4. A method as in claim 3, said uid cementitious material being in the class including hydraulic cement mortar and chemical mortar.

5'. A method as in claim 1, said fluid cementitious material being in the class including hydraulic cement mortar and chemical mortar.

6. A method as in claim 1, including the step of projecting reinforcing means into said composite column while the same is in iluid condition.

7. A method as in claim 1, including the step of projecting elongated reinforcing means through said shaft and into said composite column while the same is in iluid condition.

8. A method as in claim 1, wherein the density of said body of agitated earth material is reduced by outward compaction thereof.

References Cited UNITED STATES PATENTS 1,943,914 1/1934 -Flock 61-35 3,023,585 3/1962 Liver 61-36 FOREIGN PATENTS 256,150 8/ 1926 Great Britain.

JACOB SHAPIRO, Primary Examiner U.S. Cl. X.R.

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