US 3391544 A
Description (OCR text may contain errors)
July 9, 1968 D. s. DACZKO MEANS AND METHOD OF FORMING CONCRETE PILES 2 Sheets-Sheet 1 Filed Dec. 5, 1966 GROUT RESERVOIR FIG.2
INVENTOR. DONALD s. DACZKO BY 40;. m $44M ATTORNEYS July 9, 1968 D. s. DACZKO MEANS AND METHOD OF FORMING CONCRETE FILES 2 Sheets-Sheet 2 Filed Dec.
. I I I m T N E V m S. DACZKO 4a,, 5W 8 MM ATTQRNEYS United States Patent Ofice 3,391,544 Patented July 9, 1968 3,391,544 MEANS AND METHOD OF FORMING CONCRETE FILES Donald S. Daczko, Bedford, Ohio, assignor to Intrusion Prepakt, Inc., Cleveland, Ohio, a corporation of Ohio Filed Dec. 5, 1966, Ser. No. 599,185 Claims. (Cl. 61--53.64)
ABSTRACT OF THE DISCLOSURE This application discloses an auger type drill which is used to form concrete piles or pillars below the surface of the earth which support buildings or otherwise formed foundations. The piles transfer the loading to firmer soil at greater depths or to underlying bedrock.
This particular drill has the normal hoisting means to support the apparatus, a motor for turning the drill and an injection hose to supply mortar to the drill. The drill itself comprises a hollow shaft through which mortar passes and about which a spiral blade is located.
A lead flight of the blade turns about the shaft and a second flight, spaced from the first flight, has an oppositely directed pitch so that as the shaft is rotated, soil is compressed between the lead and second flight thereby forming a seal through which grout will not penetrate. The utility of such an invention is inherent in the necessity of using grouts under high pressure and restricting them to the portion below the lead flight so that the grout does not creep upwards along the drill. The remainder of the shaft may have a helical auger blade having substantially the same pitch as the lead flight.
The method of using the drill is to place it in the soil, rotate it thus compressing soil along a portion of the drill between two oppositely directed flights of auger blade and discharging mortar through the hollow shaft.
Background of the invention This invention relates to the means and method of forming concrete piles by injecting cementitious material or mortar into the soil. More specifically, this invention relates to a specific auger blade mounted around the length of a hollow shaft which is inserted into the soil and ejects a cementitious material.
The earths surface is often not stable enough to support loads imposed by modern structures. To assure a proper foundation, concrete supports or piles are placed in the soil. By this means loading is transferred to firmer soils at greater depths or to underlying bedrock. A castin-place concrete pile has proven to be one of the best and most versatile methods of supporting land-based structures.
When forming a concrete pile, it is often desirable to force the concrete or mortar into loose soil or into fissures under high pressures and thereby compact weak soil zones. In order to pack the concrete under such high pressure, however, it is necessary to maintain a seal between the portion below the injection point and the point above it or the concrete will have a tendency to creep upwards along the periphery of the pipe.
Presently three types of injection apparatus are in use. The first is a simple pipe which is advanced into the ground by driving, rotating, pulling down, or jetting which may or may not have a cutting bit at its lower end. There are outlet ports at the lower end of the pipe through which grout may be forced into the soil. The grout penetrates laterally into the soil a distance depending upon its density and porosity. However, after modest build-up of pressure within the grout, it has a tendency to flow upwardly along the periphery of the pipe until it emerges at the grounds surface. As the pipe is slowly withdrawn from the soil, a column of grout will be formed in the area vacated by the pipe along with the modest penetration into the soil.
The second type of injection apparatus consists of a hollow shaft about which a continuous auger blade is mounted. Such an embodiment is shown in United States Patent No. 2,729,067 to Raymond Patterson. It is therein disclosed that after the drill has been rotated or otherwise forced into the ground that mortar is inserted through the shaft to thereby form a cementitious pile. As the cement or grout is forced into the earth and pressure builds up within the grout, it naturally forces the drill upwardly out of the earth. Some lateral penetration of the soil may occur, but the extent of this penetration is limited by the grout pressure necessary to lift the earth-filled auger drill along the sheet plane formed by the external diameter of the auger flight.
The third type of apparatus is described in United States Patent No. 3,206,936 issued to H. L. Moor. The apparatus in Moor is substantially the same as that in Patterson but only has an auger blade at its lower end. However, the method of using the apparatus and inserting the grout is substantially different. In this patent a technique is used wherein the drill is inserted to a predetermined depth and then lifted without rotation to compact the earth above and around the drill and thereby form a seal of some type. In this manner the grout may thereafter be forced through the hollow shaft and into the soil at high pressures in order to substantially penetrate into the surrounding soil. Because of the seal formed from compressing the soil above the drill, the grout will not creep upwards around it. A disadvantage of such a procedure is that the drill itself requires a very high force in order to lift the drill and the surrounding soil from the bottom of the hole to the top of the surface. This force necessarily includes the weight of a wedge or cone of earth from the top of the auger bit to the surface. The weight of the wedge of earth extends from the apex at the top of the auger bit to a greatly enlarged base at the ground surface. In soils of commonly encountered density, the side of this wedge will form an angle with the vertical generally between 30 and 45.
In short, up to now there has had to exist a compromise. If a drill were to be easily removed from its position in the earth, then large pressures could not he used to obtain the maximum lateral distribution of mortar. If better lateral distribution with accompanying high pressures was desired, it was necessary to use large forces and equipment to move the drill.
Summary of the invention The present invention provides a device which facilitates the insertion and withdrawal of an auger drill and yet permits the injection of mortar into the soil at very high pressures.
The means for accomplishing these ends is an auger drill having a hollow shaft through which mortar or concrete may pass. An auger blade spirals about the hollow shaft and has a first flight at one end of the shaft with a pitch such that it will dig when placed in contact with the ground and rotated. At a distance away from the first flight, in which distance there is nothing on the shaft, a second flight with an oppositely directed pitch is found. In this manner, by rotating the drill the earth is compacted between the oppositely pitched flights. The compacted earth forms a high pressure seal between the injected mortar and the area above the first flight, thus permitting high injection pressure. Moreover, the
rotation of the drill facilitates its withdrawal with only a relatively small amount of force.
FIG. 1 is an anger type drill which is the subject of this invention, positioned above the earth.
FIG. 2 illustrates the drill after it has been inserted into the ground.
FIG. 3 shows the insertion of grout into the hole made by the drill and the removal of the drill from the earth.
FIG. 4 shows a completed concrete pillar formed by the auger type drill of this invention.
FIG. 5 is a cross sectional view taken through 5-5 of FIG. 3.
FIG. 6 illlustrates the use of the drill to place grout in the ground under high pressure.
FIG. 7 illustrates the use of the present invention to fill lesions in the earth with grout.
This invention contemplates an auger type drill 1 having a hollow shaft 2 about which a helical blade 3 is mounted. At one end of the shaft 2 is a tip screw 5 which makes the initial penetration and path for the shaft 2. At the same end of the shaft 2 as the tip screw 5 is a lead flight 6 of the helical blade 3. At a distance removed from the lead flight 6 is a second flight 8 which has an oppositely directed pitch from the first flight 6. It has been found that if the distance between the lead flight 6 and the second flight 8 is equal to the vertical distance of one flight, desirable results are obtained. The distance may vary, however, and the drill will still be operable. Above the second flight is tre remainder of the helical blade 3 and has a pitch similar to the lead flight 6.
A rotating means 10 is attached to the shaft 2 in order to rotate it. This is usually in the form of a motor or the like. A grout inlet hose 9 is attached to the hollow shaft 2 and a hoisting means generally indicated as 11 is used to support the entire assembly. A hook 12 holds the hoisting means 11 and is held by a crane or other support of some type which is commonly known in the art.
Radially directed arms 13 extend from the sides of the rotating means. The radially extending arms 13 are used to secure cables 15 or other flexible members which may be used to pull the entire drill assembly downwardly. The cables 15 pass around pulleys 17 which are held by axles 13 to a bracket 16. A downward force may be exerted on the drill by means of the flexible cables, thus causing it to penetrate the earth more quickly during a drilling operation. The cables 15 may also be used to stop the drill from ascending when extremely high grout pressures are attained.
The drill 1 is usually rotated (FIG. 2) in order to insert it into the earth 21. However, if the ground is soft enough, it may be simply pushed down into the earth by means of the cables 15.
Once inserted into the ground, the drill is continuously rotated in the direction in which it would penetrate the ground. In this case this is clockwise rotation as viewed from the top of the drill. However, if the pitch of the helical blade 3 were reversed, the direction would be counterclockwise As the drill is rotated in a clockwise direction, the lead flight 6 has a tendency to dig into the earth 21. However, if the drill It is maintained at a constant elevation and rotated the tendency is for the lead flight 6 to push the soil upward. In opposition to this, the second flight 8 with its oppositely directed pitch has a tendency to push the earth downwardly with the net result being that the soil (FIG. 3) between the lead and second flight is under very high compression.
A consequence of this soil under high compression is to push outward against the surrounding soil. In this manner it forms a type of seal which will not be penetrated by grout under pressures in excess of 100 pounds per square inch. Thus, while rotating the drill 1, and
maintaining the drill at a constant elevation or very slowly raising it to the surface, grout is discharged through the end of the shaft 2 and deeply penetrates the surrounding soil. As discussed earlier, if the seal or compressed soil 25 were not in place, the mortar 23 would have a tendency to creep up along the periphery of the drill and the hole. The cables 15 may be utilized to hold the drill at a constant elevation while it is rotated if the pressure should become too great.
In the normal case, as the drill is rotated, soil 22 will be brought up to the surface of the earth and the compressed soil 25 at the end of shaft 2 will be sufficient to stop any flow of grout past the first flight 6 of the drill 1. It will be noted in FIG. 3 that small pockets of grout 26 are formed when the earth or soil is displaced due to the grout expanding.
The completed generally cylindrical pillar is shown in FIG. 4. FIG. 5 indicates that the small pockets of mortar 26 expand outwardly from the diameter of the helical blade 3.
If the drill 1 is held at a constant elevation and the mortar is discharged at high pressures, it is possible to create large pockets 27 (FIG. 6) in the earth. These expanded pockets 27 lend stability to the concrete piles.
FIG. 7 further indicates that grout 31 may be inserted into lesions 30 below the earths surface by the use of this invention. By simply maintaining a first flight 6 at a height above the lesion 30, the seal of soil between the first flight 6 and the second flight 3 forces the grout 31 into any openings that are available.
The use of the above described auger drill to form concrete piles generally comprises inserting the auger drill into the soil either by drilling or merely forcing it into place, and rotating the drill, thus compressing the soil along a portion of the auger drill between two oppositely directed flights of auger blade. Mortar is then discharged through the hollow shaft below the oppositely directed blades on the auger blade in order to form a concrete pile.
For ease of description, the principles of the invention have been set forth in connection with but a single illustrated embodiment. It is not my intention that the illustrated embodiment nor the terminology employed in describing it be limiting inasmuch as variations in these may be made without departing from the spirit of the invention. Rather I desire to be restricted only by the scope of the appended claims.
I claim: 1. An auger-type drill comprising: a hollow shaft through which mortar may pass; a helical blade about said hollow shaft, said blade having a lead flight at one end of said shaft with a given pitch;
said blade having a second flight with an oppositely directed pitch from said lead flight at a distance from said first flight whereby soil will be compressed between said first and second flights as said shaft is rotated, thus forming an effective seal between the end of said shaft and that portion above said first and second flights;
said blade having other flights which have a pitch in the same direction as said lead flight and are located between said second flight and the other end of said hollow shaft.
2. The auger-type drill of claim 1 wherein said lead flight extends at least 360 about said shaft.
3. The auger-type drill of claim 2 wherein said second flight is at a distance of at least one (1) flight from said first flight and extends at least 360 about said shaft.
4. The method of forming concrete piles below the surface comprising:
inserting an anger drill into the soil;
compressing the soil at a portion along said auger drill by rotating a hollow shaft on which two spaced op- 5 6 positely directed flights of auger blade are located; References Cited and UNITED sTAT PATENT discharging mortar through said hollow shaft below ES S said oppositely directed flights of auger blade as 2,352,412 6/1944 Sandstone 175-323 X said auger blade is rotated and withdrawn. 5 3,336,760 8/1967 Landau 61 53-6 h5. 'ljhe pgoceis of formirzig colgcrete fpiles of cliairlrlraf i FOREIGN PATENTS w erein sai so' is conveye to t e sur ace as sai s t is rotated by means of flights along the length of said 293396 8/1916 Germany Shaft; and JACOB SHAPIRO, Primary Examiner.
withdrawing said auger drill from the soil as said 10 mortar is discharged under high pressures. DAVID WILLIAMOWSKY, Exammelfi