US3359742A - Method and apparatus for securing anchorage in loose and compact ground - Google Patents

Description

Dec. 26, 1967 c, E. BLATTER METHOD AND APPARATUS FOR SECURING ANCHORAGE IN LOOSE AND COMPACT GROUND Original Filed July ll, 1965 4 Sheets-Sheet l ATTORNEY 4 Sheets-Sheet 2 DeC. 26, 1967 C, E, BLATTER METHOD AND APPARATUS FOR SECURING ANCHORAGE IN LOOSE AND COMPACT GROUND Original Filed July ll, 1965 da SIVNTOR vm mm C. E. BLATTER METHOD AND APPARATUS FOR SECURING ANCHORAGE Dec. 26, 1967 IN LOOSE AND COMPACT GROUND Original Filed July ll, 1963 FIG. Z0

I lNv NTOR ATTORNEY Dec. 26, 1967 c. E. BLATTER METHOD AND APPARATUS FOR SECURING ANCHORAGE IN LOOSE AND COMPACT GROUND Original Filed July ll, 1965 4 Sheets-Sheet 4 Iii/6.1.8

. INVENTOR www WAM,

ATTORNEY United States Patent O 3,359,742 METHOD AND APPARATUS FOR SECURING ANCHORAGE 1N LOOSE AND COMPACT GROUND Charles Ernst Blatter, Zurich, Switzerland, assignor to Swissboring Schweizerische Tiefbohru. Bodenforschung, A.G., Zurich, Switzerland, a corporation of Switzerland Continuation of application Ser. No. 294,280, July 11, 1963. This application Sept. 13, 1966, Ser. No. 589,175 Claims priority, application Switzerland, July 30, 1962, 9,101/62 7 Claims. (Ci. 61-53.58)

This application is a continuation of Ser. No. 294,280, tiled July 11, 1963, and now abandoned.

The instant invention relates to a method for securing or installing anchorages in loose, as well as compact, ground and also apparatus for practicing the method.

In the prior known methods, injection anchoring rods of either armor steel or bundles of steel wires, are inserted into holes in the ground which have previously been bored by drilling tools and pipe casings, and are cemented thereinto by injection of cement mortar or grout. For rammable substrata, a method in which anchor piles are rammed into the ground and are then enveloped and tightly held by the injection of mortar at a certain depth, is also known. Such anchoring piles are not appropriate for all types of substrata and hence are not utilizable in all instances.

The object of the instant invention is to provide a simple and inexpensive method for installing anchoring means in any type of ground whether of a looser or more compacted composition. The method of the instant invention is characterized in that a hollow anchor in the form of a rotative drilling tool is inserted into the earth by rotation drilling and is secured and held therein. The apparatus to practice the invention features an anchor in the form of a rotating boring tool or drill.

The invention is explained with reference to illustrative embodiments shown in the figures of the drawing, in which:

FIG. 1 is a longitudinal section through an illustrative anchor embodiment having an attached solid bit or reamer;

FIG. 2 is a section ofthe anchor of FIG. 1 on line II-II;

FIG. 3 is a section of the FIG. 1 anchor` on line III-III thereof;

FIG. 4 is a front View of the anchor;

FIG. 5 is a View, partially in section, of another ernbodiment of the anchor of my invention;

FIG. 6 is a section through the solid bit or reamer of the anchor of FIG. 5 on line VI-VI;

FIG. 7 is a section through the injection rings of the anchor of FIG. 5 on line VII-VII;

FIG. 8 is a longitudinal section of another illustrative embodiment of the anchor of my invention with superposed full boring bit;

FIG. 9 is an axial section through a schematic showing of an anchor during the boring period with a schematic showing of the drive for rotary movement of the boring anchor;

FIG. 10 is a showing analogous to that of FIG. 9 after boring, with the anchor in its deepest position and with the filling mass injected thereinto;

FIG. 11 is a showing analogous to those of FIGS. 9 and l with the injection means inserted in the anchor and the initial step of the first injection process completed; and

FIG. 12 is a showing analogous to those of FIGS. 9

3,359,742 Patented Dec. 26, 1967 ICC for its load, with two steps of each of two injected masses for holding the anchor securely in the ground surrounding it.

Anchor 1 for insertion into the earth, and known as an injection tension anchor, has an anchor tube 2 hav ing openings 3 and a plurality of reinforcing rings 4 about its exterior, the rings having conical shoulders facing the forward end of the anchor. Within anchor tube 2 a flushing or scavenging pipe 5 is aflixed of which pipe end, 6 is threaded as shown at 7. A full or solid ring bit 8 with lateral attachment bores 9 is welded to the `anchor tube 2 and by the attachment bores 9 in the manner shown at the collar thereof. The scavenging tube 5 is positioned in a central threaded bore 10 of the bit 8. The central bore 13 of tube 5 opens into an eccentric scavenging bore 11 of the solid bit 8, and, as shown in FIG. 4, the bit 8 is provided with prisms 12 of hard metal distributed over the front surface of the bit so that on rotation the ground is bored circularly.

Anchor tube 2 is in the form of a thick-walled steel tube normally of a length of some 25 to 30 feet. As required by the predetermined total length of the anchor, these anchor tubes are joined to each other either by welding their ends or by threaded coupling sleeves. Instead of the hard metal prism bit 8 shown in FIGS. 1, 2 and 4, a diamond bit may be used. Bit 8 forms an integral part of the anchor. It remains in the ground with it and cannot be recovered or retrieved. Opening 3 provided in the lower partvof anchor tube 2 has as its purpose to permit the injected material to ow laterally therefrom while reinforcing rings 4 increase the adhesive strength of the anchor in order to produce a serrating of the injected mortar as below described in greater detail. The flushing or internal pipe 5, which is `screwed to the inner wall of bit 8 at its front end and, after the boring and injection of the fill are completed, is unscrewed and 14 and serves for connecting it with the structural ele` ment to be anchored or as a connecting thread for the next anchor tube.

In a further embodiment shown in FIGS. 5 to 7 of a injection anchor 20, `a flushing tube 21 of vplastic is enveloped by an anchor pipe 22 (FIG. 5). The tubular end 23 of anchor pipe 22 is an externally threaded tube 24 functioning as the connecting means of injection rings Z5. These rings have openings 26 corresponding to openings 3. of the first described illustrative embodiment. Cascade-shaped injection rings 25 are connected by threading 28 to Ian intermediate nipple 27 of which the free end serves the purpose, by means of threads 29, of connecting a solid bit 30 to the anchor. On its front face this solid boring bit 30 has recesses 31 to provide for installing prisms 32 of hard metal. The bit is also provided with a flushing bore 33 eccentrically disposed relative to the axis of the anchor as an extension or continu-l ation of a central bore 34 of the flushing pipe 21. An insert nipple 35- provided with external threading is provided for screwing into the internal threading 36 of lthe boring bit 30. Nipple 35 has a conical gripping surface 37 and, using a square key which fits into the square aperture 38 of the nipple 35, this may be screwed into boring bit 30 provided with a conical bore 39. Conical bore 39 and conical gripping surface 37 serve to clamp and tightly hold the conical end 40 of the inner .tube as to 11 with a completely inserted and lled anchor readied shown in FIG. 5.

which bores its own bore-hole and in which it is ultif matelyfastened in and to the ground. After the drilling has been completed and the anchor has reached its requisite depth, a fill mass, for example in the form of mortar, is injected under pressure through the central bore 34 thereof whi-ch served for water fiushing during drilling operation. Instead of mortar, an appropriate synthetic filling mass may be injected. Such filling mass rushes out of the front through trhe boring bit 30 and fills the space between the anchor and the walls of the drilled hole. Subsequently, the inserted nipple 35 oan be loosened `by means of the square key attached to the end of a long rod and introduced through the flushing tube 21 into the square aperture 38 of the nipple 35 so that the latter may be withdrawn with flushing tube 21. Whereupon the anchor is ready to be affixed in and to the ground by means of the material injected thereinto by way of apertures 26 in predetermined manner.

In the modified embodiment of an injection anchor 50 shown in FIGURE 8, an anchor tube 51 is provided with elongated apertures 52 of which but one is shown. Tihe far end 53 of' anchor tube 51 is externally threaded 54 for attachment to the succeeding anchor tube section or to the structural element provided for anchoring. The end 55 of such tube is likewise externally threaded at 56. A flushing pipe 57 is disposed axially within, and enveloped by, anchor tube 51, its end 58 having internal t-hreading 59 ,as also a conical gripping surface 60. This flushing pipe 57 is connected to a nipple 61 whose end 62 is externally threaded 63 :as is 'also its other end 64 at 65, the latter connecting the nipple with a non-coring drilling bit 66, as shown in FIGURE 8. The drilling bit 66 has prisms of hard metal 67 and is provided with an eccentric flush hole 68 which `forms a continuation of flushing tube 57 and of nipple 61. T-he boring bit 66 is connected by threading S6 with the 'anchor tube 51 of the injection anchor 50. The mode of operation of this anchor, which likewise functions as a drill in its first phase with the drilling by means of non-coring bit 66 and its hard metal prisms 67, is such that it remains in the ground `as a tension anchor, tand thereupon is fastened therein in the above described manner.

The attaching threads and threading of the described anchor structures are such that during the boring operation they do not loosen but, on the contrary, tighten.

With reference to FIGURES 9 to 12, the method of installing the above anchoring structures in both loose and compacted ground is shown phasewise. FIGURE 9 schematically shows the insertion of an injection tensil anchorage of my invention in the drilling phase during which the non-coring -bit y8 bites into the ground 70 to produce the drilled bore for insertion of the tension anchor. Anchor 1 is fixed in a holding member 71 so that the anchor is driven by rotation and simultaneously axially advanced by a drilling machine 72. An electric motor 73 by way of driving belt 75 rotates a flywheel 74 which transmits its rotary motion to anchor 1 by way of gearing, not shown. The drill advancing force is transmitted by the holding member 71 to anchor tube 2 which it engages, and thus the non-coring bit 8 and the hard metal prisms 12. Depending on the length of injection tension anchor 1, additional sections of anchor tube are attached to the first section 2 of the anchor tube, also increasing the length of flushing tube so that a flushing water source 76 can be connected thereto. A stream of water 77 is forced through ushing pipe 5 during the drilling operation and leaves at the front through the central, but eccentric, flush port 11 of the non-coring bit 8 and, flowing out about the bit, carries with it the loosened earth which flows upwardly between the anchor pipe 2 and the walls of the drilled hole. The tension anchor serving as the drill is advanced in the ground in the stated manner.

In FIGURE l0 there is depicted that phase of the installation procedure in which the drilling has been completed and the anchor 1 has reached the predetermined depth in the ground. In accordance with the depth of the drilled hole, respectively, the required length of the injection tension anchor, the successive sections of the anchor tube 2, are interconnected by coupling sleeves 78, and the free end of the last in succession of the flushing pipe sections 5, project beyond the last of the successive anchor tube sections 2 and serves as the element to which the fillng material injecting device is connected. By means of this device, a filling material, which usually is a cement ymortar but may, inter alia, also be a synthetic material, is injected into the flushing tubing 5 and fills the interstices between anchor 1 and the walls of the drilled hole, as described. This initial forcing of the filling material through the flushing or inner piping 5 serves in the later phases to prevent the rising of the injected mass at the exterior of the anchor during subsequent injections. The injected mass is of such composition that on freezing, hardening or solidifying, it does so Without any decrease in its volume and such that the solidified mass can be burst at a predetermned internal pressure applied thereto. After this initial injection, the inner or flushing tube 5 is unscrewed and pulled out, and the interior of the anchor tube 2 is cleansed by washing.

After the injected filling mass has sufficiently set and hardened, the anchor is cemented in by stepwise pressure grouting with cement mortar or other fastening material in the direction from bottom to top with the aid of the injecting mechanism 91 (FIGURE 11).'This mechanism has an injecting piston or packer 92 and a supply line 93. Between two sealing regions, packer 92 operates in a hollow region between such two sealed regions, in which hollow region the material to be injected, by way of appropriate apertures, is fed from supply line 93. Relative to bores 3, the injecting mechanism 91 so presses the lnjection material into anchor tube 2 that at the region of the desired injection, bores 3 are between lthe two packed regions of the hollow region of packer 92. By forcing the injection mass through the injecting mechanlsm 91, the injection mass ows through the supply line 93 and passes into the described hollow region, is forced th-erefrom through bores 3, and, on reaching the predetermined pressure, bursts the filling material 180. Through the channels 95 produced by such bursting, the mjectlon mass is forced into the ground around the anchor. In FIGURE ll, the first stage of the first injection 94 1s shown. The diameter of the injection packer 92 may be appropriately fitted to the internal diameter of anchor tube In that the inventive method permits of repeated injections at stepwise increased pressure, excellent anchorlng 1n the ground is obtained. FIGURE 12 shows an anchor of the invention of which the embedding in the ground has been completed. As described above, a first injection mass 97 was pressed thereinto in the second phase and two further injections masses, 98 and 99, in twoadditional phases. The number of injection or extrusion phases, and the pressures thereof, depend on the required resistance of the completely installed injection anchor. After the injected masses have hardened and sol1dified, the tension anchor of the invention is ready to be connected by the fastening element 100 to the structure provided therefore. Furthermore, there is the possibility of remforcing the anchor tube by insertion thereinto of one or more additional tension rods or bunches of cables or wires of high strength and to connect such bunches with the anchor tube or boring bit by threaded couplings. It will be noted that such reinforcing members may be pretensioned in such manner that pretensioned anchors are formed. So also reinforcing members may be cast in the anchor tubes, in which event the interior surfaces of the anchor tubes are preferably provided with elements, for example irregularities therein, which improve the adhesion between the casting material and the anchor tubes.

The instant inventions have, inter alia, the following advantages over the prior art:

The installation of the tension anchor, consisting essentially of the steel tube, is accomplished by the tension anchor itself; l

The installation (drilling) is possible by a rotary movement of the tension anchor;

The anchor tube serves as drill rod while drilling;

The tip of the anchor is a drill bit which remains in the ground;

For introducing water for ushing while drilling and for injecting a filling mass into the hollow region between the anchor tube and the ground, an inner tube is removably connected with the tension anchor;

The structure of the inventive tension anchor permits of repetitive and stepwise injection of the filling mass, with the composition of the filling mass and the .pressure utilized for each injection adapted to the requirements to be met by each individual injection step;

The sinking of the anchor by rotary drilling can be done by using a common rotary drilling equipment;

The provision of lateral apertures in the anchor tube and the use of the sealed packer permit repetition of the injection in each section of the anchor any number of times, and the composition of the filling mass and the pressure under which it is to be injected, can be varied to meet requirements at each stage; and

Section after section of the .required length of the anchor can be drilled into the ground and installed, and, as will be readily noted from the above description of the method, the grouting may be done in any amount for any required lengths, in any desired sequence, in any desired number of operations, and with any desired pressure.

The inventive injection anchor can -be used in all types of soil and rock formations, that is, in cohesive and noncohesive ground or earth including rock debris or moraine, as also in soynd or decomposed rock. It must be emphasized that even where ground water under pressure is present, the execution of the anchor is possible without difiiculty. Also, my inventive method can be used for the sinking and construction of foundation piles. I mention as particularly useful fields of use, the anchoring of cutoff concrete walls, walls of piles, sheet pilings, bulkheads, etc., mine safety shafts, masts for carrying high tension lines, cable railways, cable lifts, cable cranes, etc., penstock foundations, harbour installations, quay walls, retaining walls, protection galleries, etc.

I claim:

1. A method of securing elongated tubular shaft means having at least one radial aperture intermediate its ends in a bore hole in the ground having a diameter greater than the outside diameter of the tubular shaft means, comprising the steps of injecting into the space between the outer surface of said shaft means and the inner surface of said bore hole a first owable and hardenable material, adapted to fracture in its hardened condition at a predetermined pressure, to substantially ll said space; permitting said material to harden so as to form a mantel of hardened material about said shaft means; subsequently injecting through said tubular shaft means and said aperture therein additional hardenable material at a pressure at least equal to said predetermined pressure to fracture said mantel of hardened material and to cause said additional material to pass through the fractures into the ground surrounding said mantel while lling said fractures; and permitting said additional material to harden in said fractures and about said mantel of hardenable material.

2. A method as set -forth in claim 1, wherein said first injected hardenable material is a material which hardens substantially without shrinking.

3. A method as set forth in claim 1, wherein said tubular shaft means is provided with a plurality of radial apertures axially spaced from each other, and wherein said additional -material is injected in successive steps through said axially spaced apertures, respectively, starting with the lowest one of said apertures.

y4. A method as set forth in claim 3, wherein said successive injections of said additional material are respectively carried out at different pressures.

5. A method as set forth in claim 1, wherein said rst material is injected centrally through said tubular shaft means to pass through the bottom end of the latter into said space.

6. A method as set forth in claim 1, wherein said tubular shaft means include a drill bit at the bottom end thereof, and including the step of boring said bore hole by means of said drill bit on said shaft means.

7. Combined tubular drill and anchor means comprising, in combination, elongated tubular shaft means including at least one elongated tube having an open bottom end and being formed in the wall thereof with at least one `radial aperture upwardly spaced from said bottom end, and a drill bit fixed to said bottom end and formed with a flushing opening therethrough; and a flushing pipe extending axially through said tubular shaft means and having a bottom end removably connected to said elongated tube in the region of the bottom end of the latter and communicating with said flushing opening through said drill bit, whereby after boring of the bore hole in the ground by means of said combined drill and anchor means a rst hardenable material may be injected through said flushing tube and said flushing opening in said drill bit to rise in said bore hole about said tubular shaft means to form after hardening a mantel of hardened material about said shaft means, and after lremoval of said flushing tube a second hardenable material may be injected through said tubular shaft -means and said aperture with a pressure sufficient to fracture said mantel so that said second material may pass through the fractures into the ground.

References Cited UNITED STATES PATENTS 2,079,941 5/1937 Labarre 175--246 2,230,568 2/1941 Howard et al. 175-246 2,412,239 12/1946` Weber 61-53.58 2,923,133 2/1960 Muller 6'1-5358 JACOB SHAPIRO, Primary Examiner.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,359,742 December Z6, 1967 Charles Ernst Blatter It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should reed as Corrected below.

In the heading to the printed Specification, line 10, for "589,175" read 579,175

Signed and sealed this 4th day of February 1969.

(SEAL) Attest:

Edward M. Fletcher, Jr. EDWARD J. BRENNER Attesting Officer Commissioner of Patents

Claims (1)

1. A METHOD OF SECURING ALONGATED TUBULAR SHAFT MEANS HAVING AT LEAST ONE RADIAL APERTURE INTERMEDIATE ITS ENDS IN A BORE HOLE IN THE GROUND HAVING A DIAMETER GREATER THAN THE OUTSIDE DIAMETER OF THE TUBULAR SHAFT MEANS, COMPRISING THE STEPS OF INJECTING INTO THE SPACE BETWEEN THE OUTER SURFACE OF SAID SHAFT MEANS AND THE INNER SURFACE OF SAID BORE HOLE A FIRST FLOWABLE AND HARDENABLE MATERIAL, ADAPTED TO FRACTURE IN ITS HARDENED CONDITION AT A PREDETERMINED PRESSURE, TO SUBSTANTIALLY FILL SAID SPACE; PERMITTING SAID MATERIAL TO HARDEN SO AS TO FORM A MANTEL OF HARDENED MATERIAL ABOUT SAID SHAFT MEANS; SUBSEQUENTLY INJECTING THROUGH SAID TUBULAR SHAFT MEANS AND SAID APERTURE THEREIN ADDITIONAL HARDENABLE MATERIAL AT A PRESSURE AT LEAST EQUAL TO SAID PREDETERMINED PRESSURE TO FRACTURE SAID MANTEL OF HARDENED MATERIAL AND TO CAUSE SAID ADDITIONAL MATERIAL TO PASS THROUGH THE FRACTURES INTO THE GROUND SURROUNDING SAID MANTEL WHILE FILLING SAID FRACTURES; AND PERMITTING SAID ADDITIONAL MATERIAL TO HARDEN IN SAID FRACTURES AND ABOUT SAID MANTEL OF HARDENABLE MATERIAL.

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