DRILLING MEANS SERVING AS GROUND ANCHOR AND METHOD

Abstract: A ground- or soil anchor is prepared and placed in the ground by drilling a bore hole at the chosen site by means of a drilling assembly which comprises an elongated tubular member (1) which serves as a drive shaft for the drill (8), which latter has a tapering rear end and is designed to be pulled into the said tubular member (1), the leading end of which is split so that the parts thereof - on the drill being pulled into it are spread apart and are eventually embedded in grout inserted into the bore hole.

Description: The present invention relates to sail or ground anchors and more particularly to means and a method to create and to place in situ a soil anchor. When eventually in place the anchor obtained by the new method and the means therefor is substantially identical with conventional soil or ground anchors and as such is well known to men of the art, thus a detailed description of the anchor being superfluous. From US-A-3 855 745 an apparatus performing an earth anchor is known, which includes rod having a pointed tip with a tapered shoulder connected at an end of the rod, the tip facilitating the driving of the rod into the earth. Over fitting the rod to bear against the tapered shoulder is a sleeve with a pre-defined division line longitudinally from an end thereof. A driving tube is fitted over the rod within the earth to drive the sleeve into engagement with the shoulder, thereby flaring the end of the sleeve of the division lines into the earth. Means are provided for securing the shaft during the driving operations to prevent the shaft from being driven further into the earth. This known earth anchor assembly has the disadvantage, that a great force is necessarily applied by impact such as by a sledge hammer in order to drive the shaft assembly directly into the ground. Moreover, obstructions in the earth like stones or other hard materials may lead to damage on the pointed tip member when this is driven directly into the ground. It is the main object of the invention to provide means and a method for drilling the hole into which the soil or ground anchor is to be inserted which eventually form themselves the operative parts of the anchor. This object is achieved by the features of the independent claims. Conventionally soil anchors are placed in a previously, separately prepared bore hole, which - as is known - is then cast out with concrete grout or chemical substances. The new method and the new means dispense with separately drilling the bore hole and subsequently placing the soil or ground anchor in it. Contrarily to known practice the drilling means - at a certain stage of the drilling operation - are transformed into operative parts of the soil or ground anchor. It is obvious to those skilled in the art that the new method thus constitutes a considerable economic advantage over the conventional method. According to a preferred embodiment of the present invention said elongate tubular member has an exterior, continuous helical ridge. According to preferred embodiments of the inventive method, the soil is conveyed to the top of the bore hole by a stream of flushing water or by being lifted on a helical ridge, provided on the exterior of the tubular member. The new means are shown schematically in sectional view in the accompanying drawings, wherein Figs. 1 - 5 illustrate different stages of a bore hole and soil anchor according to the invention. Turning to Figs. 1 - 5 - the new device is shown to comprise a tubular member 1 which has an exterior,continuous helix 2 the lowermost end 1' of member 1 being connected at 3 with the main part of member 1. Within member 1 extends an enveloping pipe 4 and in the latter a pull rod 5 which can be operated by means of a jack or wrench indicated schematically at 6. The lowermost portion 1' of member 1 - which, as has been stated, is detachable from the main part is lengthwise split into two halves. The lowermost section 5' of the pull rod 5 is screw connected at 7 to the main part of the rod. At the far end of rod 5 and fixed to it is provided a drilling tool 8 the rear end of which is tapering, as seen in the drawings. The new device is actuated as follows: The device is placed at the predetermined angle with the tool 8 facing the ground. Now the device is actuated imparting rotation (by conventional means, not shown) until the desired, predetermined depth of a bore hole is reached, possibly adding one or more additional tubular members with the exterior helix as well as tension rods. While this drilling operation goes on excavated soil is lifted to the surface on the helix 2. Once the desired depth of bore hole has been reached, the drill 8 is pulled up by means of rod 5 thereby causing the rear end of the tool to spread apart the two halves of portion 1′, thereby creating a cavity as shown in Figs. 2 and 3. The said space is simultaneously filled with concrete grout or any other mass commonly used for such purposes, part of the grout or mass escaping from the space between the halves 1′ and settling around the latter. The filling in of grout or other mass occurs along the enveloping pipe 4 as indicated by arrows in Figs. 2 and 3. After spreading apart the parts of portion 1′ and inserting grout the member 1 is disconnected from its portion 1′ and is pulled out while grouting may continue. Finally the required tension is applied to rod 5 and it is secured at the surface in a conventional way. It is possible, when the anchor has been inserted for a limited period of time, to unscrew the main portion of the pull rod and retrieve it for further use. Where the anchor is to be placed in rock or firm soil where no cave in may be expected, it might be necessary to first drill the bore hole and then insert the device described above. In that case the drill used is no part of the device and only a tapering or conical member is required to spread apart the lowermost portion of the tubular member. Incidentally, while the use of the new device has been shown in connection with ground anchors, obliquely entering the ground, it is within the gist of the invention to drill vertically, e.g. where piles have to be prepared. It would be within the scope and gist of the invention to use whatever drilling tool of known type, provided that its rear end is tapering and is thus adapted to force apart the parts of the split portion of the tubular member. The helical ridge on the latter serves to convey soil to the top; where sufficient supply of water is available the elongated tubular member need not be provided with the exterior helix; the soil may be flushed out by flow of water and conveyed to the top by the flow.

Claims: Ground or soil anchor comprising an end member (8) which is attached to a tension rod (5), the said rod (5) extending to the surface of the ground at the respective site and being located within an elongated tubular member (1), said end member (8) being a body the rear portion of which, i.e. that which is connected to the said tension rod (5) is tapering towards the connection with the rod (5), characterized in that said end member is a drilling tool (8), that said tubular member (1) serves to rotate the drilling tool, and that a leading end portion (1') of the said tubular member (1) is screwed or otherwise connected with the main part thereof, said leading end portion (1') being split into at least two parts, such that on pull being exerted on the said tension rod (5), the said tapering portion of the drilling tool forces the parts of the said leading end portion (1') apart. Ground or soil anchor according to claim 1 characterized in that said elongated tubular member (1) has an exterior, continuous helical ridge (2). A method of creating a ground or soil anchor comprising the steps of: (a) drilling a bore hole by the anchor assembly of claim 1 during which soil is conveyed to the top of the hole, (b) continuing the drilling operation until a predetermined depth is reached, (c) exerting pull on the said tension rod (5) and thereby causing the split leading end portion (1') of the tubular member (1) to be spread apart, (d) casting concrete grout or other conventional material into the bore hole so as to embed the spread apart end portion of the tubular member therein, (e) disconnecting the main part of the tubular member from the split leading end portion and recovering the former from the bore hole while injecting grout simultaneously, (f) securing the surface end of the tension rod in a conventional way. The method of claim 3 wherein the soil is conveyed to the top of the bore hole by a stream of flushing water. The method of claim 3 wherein the soil is conveyed to the top of the bore hole by being lifted on a helical ridge (2) provided on the exterior of the tubular member (1).

Inventors: LIPSKER, ITSHAQ
Applicants: LIPSKER, ITSHAQ
Application year: 1987
Main classification: E02D5
IPC codes: E02D5