US3369617A - Horizontal earth boring method - Google Patents

Description

Feb. 20, 1968 J. B. BRACK ETAL 3,369,617

HORIZONTAL EARTH BORING METHOD Filed June '7, 1965 50 2 Geo/ye fl. Penn/092% 55 0 LT Char/e: J zfafi/rsan /0 m Cuff/J E. Pennmg/on 2:2 15: 5 INVENTORS v 6/ lo 55 By o #agdm d? J /0 14 TTORNE YS 3,369,617 HORIZONTAL EARTH BORING METHOD Joe B. Brack, George R. Pennington, Charles J. Johnson, and Curtis E. Pennington, Baytown, Tex., assignors, by mesne assignments, to Gilbert M. Turner, Houston, Tex.

Filed June 7, 1965, Ser. No. 461,694 4 Claims. (Cl. 17562) ABSTRACT OF THE DISCLOSURE A method of forming an enlarged horizontal bore with a reamer having forward and rearward cutting teeth, a central fluid supply passage and communicating ports adjacent the cutting teeth comprising rotating and advancing the reamer to form an enlarged horizontal bore while discharging water from the reamer to mix with the cuttings, reversing the direction of advance of the reamer while continuing the rotation to reduce the size of the cuttings, again reversing the direction of advance of the reamer to move the reamer forwardly of the cuttings and introducing compressed gas into the bore hole through the ports in the reamer to move the cuttings outwardly of the bore.

This invention relates to new and useful improvements in earth boring methods and apparatus, and particularly methods and apparatus wherein substantially horizontal holes are drilled beneath a road, railroad, or similar area.

Various work has been done in the past in the field of earth boring wherein horizontal holes are drilled beneath a road, railroad, or the like, as illustrated by US. Patent Nos. 1,932,068, 2,234,451, 2,693,345, 2,702,180, and 3,011,567. In US. Patent No. 2,702,180, a method of drilling horizontal bore holes is disclosed wherein compressed air is used to eject the cuttings from the boring or drilling operation, but such method involves a series of steps which render such method complex, Thus, in the method of Patent No. 2,702,180, a first mass of cuttings is formed, such first mass is compacted by withdrawing the reamer or drill, water is injected into the space inwardly of the withdrawn reamer, the reamer is then advanced for drilling a second mass of cuttings, the reamer is again withdrawn to compact the second mass of cuttings, and then the compressed air is used to force the two masses outwardly.

An object of the present invention is to provide a new and improved earth boring method and apparatus which uses compressed air or gas for ejecting cuttings but which obviates the complex methods employed in the prior art.

An important object of this invention is to provide a new and improved earth boring method and apparatus which is particularly suitable for drilling substantially horizontal bore holes and which is elfective for discharging the cuttings by means'of compressed gas and without compacting the cuttings with the reamer or drill or introducing liquid into a space between two compacted masses before applying the compressed air or other gas.

A particular object of this invention is to provide a new and improved earth boring method and apparatus wherein reverse reaming is effected for a triple cut accompanied by a discharge of water into the cuttings or particles to fluidize the cuttings or particles so that they may be ejected from the bore hole with compressed air.

Another object of this invention is to provide a new and improved reamer or drill which has an open face and rows of cutting teeth extending substantially radially on both the forward and rear for thereby providing cutting action when moving in inwardly and outwardly in the drilling of a bore hole.

The preferred embodiment of this invention will be de- States Patent 3,369,617 Patented Feb. 20, 1968 scribed hereinafter, together with other features thereof, and additional objects will become evident from such description.

The invention will be more readily understood from a reading of the following specification and by reference to the accompanying drawings forming a part thereof, wherein an example of the invention is shown, and wherein:

FIG. 1 is a view, partly in elevation and partly in section, illustrating the first phase of the method of this invention;

FIG. 2 is a view similar to FIG. 1, but illustrating a further phase of the method of this invention;

FIG. 3 is also a view similar to FIGS. 1 and 2, but illustrating a still further phase of the method of this invention;

FIG. 4 is an elevation of the reamer apparatus of this invention which is used in performing the method illustrated schematically in FIGS. 1-3; and

FIG. 5 is a view taken on line 55 of FIG. 4 to further illustrate the construction of the reamer of this invention.

In the drawings, the letter R designates generally the reamer or drill of this invention, which is used in carrying out the method of this invention. Briefly, the reamer R is used in drilling or cutting a bore hole B which is normally substantially horizontal. In the usual case, the bore hole B is cut or drilled in the earth beneath a road X, a railroad or other similar area. After the bore hole B is completely drilled and the cuttings therefrom are removed, such bore hole B may serve as a culvert for con ducting water or other materials beneath the road X or other similar area. As will be explained more in detail hereinafter, the method of this invention provides for a multiple cutting of the cuttings from the bore hole so as to reducethe particle size of such cuttings while also fiuidizing them with water, thereby facilitating the removal of the cuttings from the bore hole B with compressed air or other gas. The reamer R which is used in the method of this invention is of the open type and it has forward cutter teeth 10 and rear cutter teeth 12, as will be described more in detail hereinafter.

Considering the invention more in detail, the method is initiated by drilling a pilot hole 15, preferably for the full length of the section in which the bore hole B is to be drilled. Such pilot hole 15 is drilled with any conventional drill bit and is normally accomplished in a single drilling operation from one side of the embarkment E to the other. One type of standard drilling apparatus which may be used for operating the pilot bit (not shown) for drilling the pilot hole 15 and for also operating the reamer R is illustrated in United States Patent No. 1,932,068, and it in itself forms no part of this invention.

After the pilot hole 15 has been drilled, a leader pipe 16 is connected to the reamer R at the forward end of such reamer R, and a section of drill stem or pipe 20 is connected to the reamer R at its rear portion. The drill stem 20 is rotated by any suitable drilling apparatus such as that illustrated in the United States Patent No. 1,932,- 068 so as to impart rotation to the drill stem 20 and the reamer R.

The leader pipe is normally about two to three feet in length, and it is inserted initially into the bore hole 15;

then rotation of the drill stern and reamer R are commenced to begin the drilling of the bore hole B which is normally of a substantially larger diameter than the pilot hole 15. During such drilling action, the forward cutting teeth 10 on the reamer R cut the bore hole B and leave cuttings 25' of earth in the bore hole B behind the reamer R. A liquid such as water is introduced through the hollow drill stem 20 and the reamer R, as will be more fully explained in connection with the description of the ream- 3 er R hereinafter so as to distribute the water throughout the cuttings 25.

It has been found that with many types of soils the cuttings 25 may be discharged from the hole B by the introduction of compressed air or other gas in place of the liquid after the reamer R has drilled for a predetermined distance or stroke, such as three to six feet. When the compressed air or gas is used for such discharge'of the cuttings 25, the introduction of liquid into the drill stem 20 is stopped; and, instead, the compressed air or gas is introduced through the drill stem 20 for discharge at the reamer R when it is at the forward end of its stroke.

In those instances wherein the cuttings 25 are not ejected or moved outwardly of the bore hole B by the compressed air or gas after only the single stroke of the reamer R, a complex scheme has heretofore been pro posed by the prior art, as explained above, to accomplish the ejection of the cuttings. However, with the present invention, the removal of the cuttings 25 is accomplished with a relatively simple but highly effective method.

Thus, if by reason of the consistency of the cuttings 25, or if for any other reason, the cuttings 25 cannot be ejected by the compressed airor gas after the initial longitudinal movement of the reamer R throughout its stroke in one direction to a point such as indicated in FIG. 1 of the drawings, then the method of this invention includes the subsequent steps which are schematically illustrated in FIGS. 2 and 3 of the drawings. .For example, the next step of the method preferably includes the rotation of the drill stem 20 and the reamer R in the same direction as when initially drilling the bore hole 13 to the end as shown in FIG. 1, but the direction of longitudinal movement of the reamer R is reversed as shown in FIG. 2. During the reverse longitudinal movement of the reamer R, the rear cutting teeth 12 cut the cuttings 25 into smaller particles 25a which remain forwardly of the reamer R in the bore hole B, and thus compacting of the cuttings is avoided. The reverse cutting action with the rear cutting teeth 12 is preferably continued for all, or substantially all, of the distance through which the reamer R initially traveled when cutting the bore hole B with the forward cutting teeth 10.

During the reverse longitudinal movement of the reamer R, water or other liquid is discharged at the reamer R into the cuttings to further fluidize such cuttings as they are being reduced in size by the reverse cutting action of the rear cutting teeth 12.

Thereafter, the reamer R and the drill stem 20 are moved forwardly again until they reach the end of the bore hole 26, which was the initial point at which the drilling with the reamer R was stopped in the first stroke. Such position of the reamer R is illustrated in FIG. 3. During the forward movement of the reamer R for the second time, additional cutting action is obtained with the forward cutting teeth so as to even further reduce the particle size of the cuttings 25 as indicated by the numeral 25b in FIG. 3. Water or other liquid is normally introduced while the cutting steps are taking place, including the final third cutting as the reamer R is moved forwardly for the second time. Thus, the complete cutting process involves a triple cutting of the cuttings 25 to produce the smaller particle size cuttings illustrated at 2512 in FIG. 3. At the end of the stroke, with the reamer R in the position shown in FIG. 3 in contact with the forward end 26 of the bore hole B, the cuttings have been reduced in size and thoroughly mixed with water so as to be fluidized or formed into a slurry which is readily discharged thereafter by compressed air or gas.

Therefore, as illustrated in FIG. 3, the introduction of the water or other liquid is replaced by the introduction of compressed air or gas through the drill stem and the reamer R for moving the cuttings b outwardly to eject same and substantially clean the bore hole B.

The method described above is then continued for another predetermined distance or stroke, generally three 4 to six feet in length, and such method is thus repeated until the full length of the bore hole has been obtained underneath the road X or other area.

In FIGS. 4 and 5, the reamer R having the forward cutting teeth 10 and the rear cutting teeth 12 are illustrated in detail. Thus, the reamer R includes an annular reamer support or ring which is formed of metal such as steel. The space inwardly of the annular reamer support or ring 40 is open and a drill stem connector element is disposed centrally of such opening within the ring 40. The connector element 50 is supported in its central position by any suitable supports extending radially from the connector 50 to the ring 40, and as illustrated in the drawings, such supports are tubular support members 55. The inner ends of the tubes are welded to the connector element 50, while the outer ends of the tubular elements or tubes 55 are welded to the inner rim or surface of the ring 40.2

Each of the support arms or tubes 55 has a cutter blade mounted thereon with retaining bolts 61 or other suitable mounting means. Each of the cutter blades 60 has the forward cutting teeth 10 and the rear cutting teeth 12- The connector element 50 is provided with internal threads 5011 at one end for receiving a threaded male connection on the drill stem 20 (FIGS. 1-3). The connector element 50 has threads 50b formed at its forward end for making a threaded connection with the leader pipe 16 (FIGS. 1-3).

For conducting the liquid during the drilling operations with the reamer R so as to distribute such liquid throughout the cuttings, the connector element 50 is hollow and its bore 500 is provided with an opening or hole Stldfor each of the tubes 55, and in alignment therewith so that fluid from within the bore 50c flows into the interior of the tubes 55. .Each ofthe tubes 55 has a plurality of outlets 55a for directing the fluid in the direction of the forward cutting teeth 10 and other outlets 55b for directing the fluid in the direction of the rear teeth 12. When the water is introduced through the drill stem 20, it is of course discharged through the openings 55a and 5512, whereas when the compressed air or other gas is introduced through the drill. stem 20, the compressed air. or gas is discharged through the openings 55a and 55b.

Since the cutting action required during the reverse longitudinal movement of the reamer R in the direction illustrated in FIG. 2 is reduced as compared to the initial cutting action required when the reamer R is moved longitudinally forwardly for the initial cutitng. of the bore hole B, the angle of inclination of the cutter teeth.l2,.

with respect to horizontal, is normally about five degrees less than the angle of inclination of the cutter teeth 10 although they may be of the same inclination in some instances. The entire reamer R is preferably formed of. steel so that it is rugged in construction and may be used.

for many operations.

The foregoing disclosure and description of the invention is illustrative and explanatory thereof and various changes in the size, shape and materials, as well as in the details of the illustrated construction, may be made within the scope of the appended claims withoutdeparting from the spirit of the invention.

What is claimed is:

1. A method of boring a substantially horizontal hole in the earth, comprising the steps of:

(a) rotating an open reamer having forward and rear cutting teeth and moving such reamer in a longitudinal direction for cutting a bore hole with the forward cutting teeth,

(b) discharging water in proximity to the reamer for mixing with the cuttings as made by the reamer,

(c) reversing the direction of longitudinal movement of the reamer while rotating same for cutting the cuttings into smaller particles with the rear cutting teeth,

(d) thereafter again moving the reamer longitudinally forwardly of at least some of the cutting particles, and

(e) discharging compressed gas rearwardly of the reamer for moving at least some of the cutting particles outwardly in the bore hole.

2. A method of boring a substantially horizontal hole in the earth, comprising the steps of:

(a) rotating an open reamer having forward and rear cutting teeth and moving such reamer in a longitudinal direction for cutting a bore hole with the forward cutting teeth,

(b) discharging Water in proximity to the reamer for mixing with the cuttings made by the reamer,

(c) reversing the direction of longitudinal movement of the reamer while rotating same for cutting the cuttings into smaller particles with the rear cutting teeth,

(d) discharging water into the smaller cutting particles to fluidize the particles,

(e) thereafter again moving the reamer longitudinally forwardly through the cuttings until the reamer reaches approximately the inward extent of the bore hole, and

(f) introducing compressed gas inwardly of the fluidized cutting particles for moving them outwardly in the bore hole.

3. A method of boring a substantially horizontal hole in the earth, comprising the steps of:

(a) rotating an open reamer having forward and rear cutting teeth and moving such reamer in a longitudinal direction for cutting a bore hole with the forward cutting teeth,

(b) discharging water in proximity to the reamer for mixing with the cuttings made by the reamer,

(c) reversing the direction of longitudinal movement of the reamer while rotating same for cutting the cuttings into smaller particles with the rear cutting teeth,

(d) discharging water into the smaller cutting particles to fiuidize the particles,

(e) thereafter again reversing the direction of longitudinal movement of the reamer while rotating same for cutting the cuttings into still smaller particles with the forward cutter teeth,

(f) discharging water into the cuttings to further fluidize the particles, and

(g) introducing compressed gas inwardly of the fluidized cutting particles for moving them outwardly in the bore hole.

4. A method of cutting a bore hole, comprising the steps of:

' (a) drilling a pilot hole,

(b) inserting a leader pipe on a reamer having forward and rear cutting teeth,

(0) rotating the reamer and moving same longitudinally forwardly for cutting a bore hole with the forward cutting teeth,

((1) discharging water in proximity to the reamer for mixing with the cuttings as made by the reamer,

(e) reversing the direction of longitudinal movement of the reamer while rotating same for cutting the cuttings into smaller particles with the rear cutting teeth,

(f) thereafter again moving the reamer longitudinally forwardly of at least some of the cutting particles, and

(g) discharging compressed gas rearwardly of the reamer for moving at least some of the cutting particles outwardly in the bore hole.

References Cited UNITED STATES PATENTS 2,684,834 7/1954 Miller et al 175-53 2,693,345 11/1954 Martin et al. 175-384 2,702,180 2/1955 Horner 175-69 2,733,767 2/1956 Sappington 175-401 X 3,011,567 12/1961 Turner 175-62 X 3,072,205 1/ 1963 Govin 175-62 X 40 ERNEST R. PURSER, Primary Examiner.

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