EP0004150A1 - Ancre de fond et méthode pour enfoncer un tel ancre - Google Patents

Ancre de fond et méthode pour enfoncer un tel ancre Download PDF

Info

Publication number
EP0004150A1
EP0004150A1 EP79300273A EP79300273A EP0004150A1 EP 0004150 A1 EP0004150 A1 EP 0004150A1 EP 79300273 A EP79300273 A EP 79300273A EP 79300273 A EP79300273 A EP 79300273A EP 0004150 A1 EP0004150 A1 EP 0004150A1
Authority
EP
European Patent Office
Prior art keywords
anchor
members
thrust member
tie rod
earth
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP79300273A
Other languages
German (de)
English (en)
Inventor
Roger Corin Harvey
Eldon Burley
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
QMC Indusrial Research Ltd
Original Assignee
QMC Indusrial Research Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by QMC Indusrial Research Ltd filed Critical QMC Indusrial Research Ltd
Publication of EP0004150A1 publication Critical patent/EP0004150A1/fr
Withdrawn legal-status Critical Current

Links

Images

Classifications

    • E—FIXED CONSTRUCTIONS
    • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
    • E02D5/00—Bulkheads, piles, or other structural elements specially adapted to foundation engineering
    • E02D5/74—Means for anchoring structural elements or bulkheads
    • E02D5/80—Ground anchors
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
    • B63B—SHIPS OR OTHER WATERBORNE VESSELS; EQUIPMENT FOR SHIPPING 
    • B63B21/00—Tying-up; Shifting, towing, or pushing equipment; Anchoring
    • B63B21/24—Anchors
    • B63B21/26—Anchors securing to bed
    • E—FIXED CONSTRUCTIONS
    • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
    • E02D5/00—Bulkheads, piles, or other structural elements specially adapted to foundation engineering
    • E02D5/74—Means for anchoring structural elements or bulkheads
    • E02D5/80—Ground anchors
    • E02D5/803—Ground anchors with pivotable anchoring members

Definitions

  • This invention relates to an embeddable anchor for use in anchoring a structure, and especially to an embeddable anchor for use in anchoring a marine platform to the sea bed.
  • the invention also relates to a method of embedding such an anchor.
  • the anchor In the case of marine embeddable anchors and embedding processes, further constraints may be placed on the installation procedure. Thus, first it may be desirable that the anchor should be capable of being embedded by surface operations only except, perhaps, disconnection of temporary lines which could be done from a diving bell or mini-submarine. Secondly, the equipment required should be presently available or at least be in the process of rapid development.
  • a further desirable point is the ability to provide anchors of different capacities within a fairly wide range simply by scaling some or all of the variables of the anchor configuration.
  • the term "earth” should be interpreted to mean the outer layer(s) of the Earth's crust and so includes the soil on dry land and the sand or other sea bed material under the seas.
  • the present invention provides a method of embedding an embeddable anchor in the earth, the anchor comprising a tie rod on which is mounted a thrust member adapted to provide a substantial part of the resistance to lateral movement of the anchor when embedded comprising the steps of positioning the anchor above the surface of the earth and then driving the anchor into the earth until the thrust member is lodged therein.
  • the present invention also provides a method of embedding an embeddable anchor in the earth, the anchor comprising a tie rod on which is mounted, for movement along part at least of the length of the tie rod, a thrust member adapted to provide a substantial part of the resiz- tance to lateral movement of the anchor when embedded comprising the steps of placing the thrust member on the surface of the earth and driving the tie rod into the earth.
  • the thrust member may be driven into the earth either before, after or during the driving of the tie rod into the earth.
  • the present invention provides a method of embedding an embeddable anchor in the earth, the anchor comprising a thrust member, a tie rod having a container or longitudinal passage between its ends or being in the form of a hollow shaft or tube, and means for embedding the anchor in the earth, the method comprising positioning the anchor substantially vertically above the surface of the earth and driving the anchor into the earth until the thrust member is lodged in the earth, wherein binding material is disposed in the container, passage or tube prior to driving, which material is forced out of the passage or tube when the thrust member is lodged in position.
  • the present invention further provides a method of embedding an embeddable anchor in the earth, the anchor comprising a thrust member, a tie rod having a container or longitudinal passage between its ends or in the form of a hollow shaft or tube, and means for embedding the anchor in the earth, the anchoring means comprising a plurality of members having a closed or collapsed condition and an open or expanded condition, means being provided for holding the members in their collapsed condition, the method comprising positioning the tie rod substantially vertically above the surface of the earth, driving the anchor into the earth until the thrust member is lodged in the earth, and moving the said members from their collapsed to their expanded condition, said movement being achieved, at least in part, by forcing binding material from the container, passage or tube.
  • an embeddable anchor comprises a tie rod and, mounted upon the tie rod, a thrust member adapted to provide a substantial part of the resistance to lateral movement of the anchor when embedded.
  • the thrust member is movable along at least a part of the length of the tie rod.
  • the present invention further provides an embeddable anchor comprising a tie rod, a thrust member for providing a substantial part of the resistance to lateral movement of the anchor when in position, and means for anchoring the anchor in the earth, the anchoring means being secured to the tie rod at or adjacent one end thereof for providing resistance to upward movement of the anchor when in position and the thrust member being mounted on the tie rod for relative movement along the tie rod over at least part of the length of the latter.
  • the anchoring means may take the form of separate anchoring devices secured to the tie rod at spaced- apart points along the length of the tie rod. Such separate devices may include one at the end of the tie rod. In this way, the resistance of the anchor to uplift forces i.e. forces tending to lift the anchor from its embedded position is increased.
  • the separate anchoring devices may be of a form requiring movement of components of the devices to positions in which the devices develop maximum resistance to uplift forces. Such components may be actuated individually to such positions or they may be linked to a common actuator which is able to move or allow the movement of all of the components to said positions at the same time.
  • the present invention further provides a method of embedding the said anchor, which has a thrust member mounted on the tie rod for relative movement along part at least of the length of the tie rod, in the earth, the method comprising positioning the tie rod substantially vertically and partially lodging the thrust member in the earth, driving the anchoring means into the earth, until the thrust member is at the other end of the tie rod, and then driving the thrust member into the earth.
  • the present invention further provides a method of embedding the said anchor, which has a thrust member mounted on the tie rod for relative movement along at least part of the length of the tie rod, in the earth, the method comprising positioning the tie rod substantially vertically, driving the thrust member into the earth until it is partly or fully lodged in position, and driving the anchoring means into the earth until the thrust member is at the other end of the tie rod and completing the lodgement of the thrust member if necessary.
  • the present invention further provides an embeddable anchor comprising a thrust member, a tie rod and means for anchoring the device in the earth, the anchoring means comprising at least two members in the form of plates which are pivoted to the tie rod and movable between a first or collapsed condition in which the plates are substantially parallel and a second or expanded condition in which they extend transversely relative to the axis of the tie rod, means being provided for holding the plates in their collapsed condition.
  • the thrust member is of a form such that it provides a substantial part of the resistance to lateral movement of the anchor when in position.
  • the anchoring means provides resistance to upward movement of the anchor when in position.
  • the present invention further provides a method of embedding the aforesaid anchor comprising the said plates, the method comprising driving the anchor into the earth until the thrust member is lodged in position, releasing the holding means, and moving the plates from their collapsed to their expanded condition.
  • the present invention further provides a method of embedding an embeddable anchor in the earth, the device comprising the thrust member, a tie rod and the means for anchoring the anchor in the earth, the method comprising forming a substantially vertically extending hole in the earth and inserting the anchor into the hole.
  • the invention further provides a method of embedding an embeddable anchor having the features of any two or more of the methods defined aforesaid.
  • the invention further provides an embeddable anchor having the features of any two or more of the anchors defined aforesaid.
  • the invention further provides a method of embedding an embeddable anchor having the features of any two or more of the anchors defined aforesaid.
  • An advantage of having binding material in the container, passage or tube prior to driving is that it is not necessary to provide a separate line for filling the container, passage or tube after installation.
  • An advantage of using binding material to release the holding means and move the said members from their collapsed to their expanded condition is that in at least most applications binding material is required, in any event, to hold the anchoring means in position.
  • An advantage of having a thrust member which is relatively movable along part at least of the length of tie rod is that when the thrust member is partially lodge- in the earth it provides a guide for the tie rod as the latter is driven into the earth.
  • All the anchors constructed in accordance with the invention may comprise, and all the methods according to the invention may use, an anchor comprising a tie rod having a container or a longitudinal passage between its ends or in the form of a hollow shaft or tube.
  • the tie rod may be in the form of a solid rod.
  • the rod may have one or more external longitudinal grooves along its length through which a mechanism for releasing the movable members comprising the anchoring means.
  • All the embeddable anchors constructed in accordance with the invention may comprise, and all the methods according to the invention may use, an anchor with anchoring means comprising a plurality of members having a closed or collapsed condition and an open or expanded condition and means for holding the members in their collapsed condition.
  • the means may comprise one or more explosive bolts which hold the members in the closed or collapsed state until movement to the open position is required.
  • the explosive charge or charges is or are then set off and then either the members are forced to their open positions by the explosion or are released to be moved to those open positions by some other mechanism.
  • the explosive material in the bolt or bolts may be set off by a triggering device mechanically operated by a suitable mechanism operated by remote control or by a control signal, for example a radio signal or an ultra sonic signal.
  • the members may be so shaped that, after they have been released, further embedding movement of the anchor causes the members to move into their open positions.
  • All the embeddable anchors constructed in accordance with the invention, except that device having a thrust member mounted on the tie rod for relative movement along part at least of the length thereof, may comprise, and all the methods according to the invention, except that using the relatively movable thrust member, may use an anchoring device comprising, a thrust member which is secured to that end of the tie rod remote from the anchoring means.
  • binding material may be forced from the container, passage or tube to release the holding means.
  • the holding means can be released by an explosive charge or by a cutting operation.
  • the explosive charge may be set off by a signal transmitted from a position remote from the anchor.
  • the signal may be a radio signal or a signal at an ultra-sonic frequency.
  • binding material may be used to effect the total movement of the said members.
  • the holding means may be released before driving is complete, the members being partially moved towards their expanded condition by completing the driving operation and then being moved into their expanded condition by the binding material.
  • Holding means may be provided for holding the members in the open or expanded condition.
  • the holding means may be self-locking when the members are in the condition just mentioned.
  • reinforcing material for example in the form of a helical winding of reinforcement, may be arranged in the container, passage or tube and forced out by the binding material.
  • the reinforcement serves to reinforce the bulb formed around the anchoring means.
  • the method may further comprise releasing the holding means, for example by an explosive charge or by a cutting device, prior to completion of the driving operation, and moving the said members from their collapsed condition by completion of the driving operation.
  • This method is of particular advantage when the members are constituted by the said plates.
  • an explosive charge may be used to effect partial movement of the said members from their collapsed to their expanded condition.
  • an explosive charge may be used to effect the total movement of the said members.
  • binding material may be passed down the hollow shaft or passage after the anchoring device has been installed.
  • step can be replaced or supplemented by forming a substantially vertically extending hole in the earth and inserting the anchor into the hole. If the hole is made deep enough, then no driving will be required but if the length of the hole is less than the length of the tie rod, then driving may be required to complete installation of the anchoring device after it has been inserted into the hole. Preforming a hole in this way may be necessary, for example where the anchoring device is to be installed in rocky terrain. If necessary the base of the hole may be under-reamed.
  • the holding means may comprise locking bolts which can be sheared by cutting when required to be released.
  • Such locking bolts may be used if the said members are in the form of flukes or plates (which may be pivoted to the tie rod).
  • the said members may together define a hollow, for example a tubular chamber, the said members being frangibly connected together, for example by lines of weakening.
  • the holding means is constituted by the frangible connections which may be broken by the pressure of the binding material or by explosion of an explosive material in the hollow chamber.
  • the embedding operation is accomplished by an underwater hammer. This allows the anchor to be embedded almost entirely by surface operations.
  • anchor cable(s) are attached to the device before driving so that the device would be ready for service as soon as the anchoring means is properly installed.
  • the cable(s) may be attached by connections including universal joints or other means which permit a required degree of movement of the cable.
  • the cable may be connected after installation of the anchor.
  • the binding material may be mortar, concrete and/or an epoxy resin.
  • the binding materLal When the binding materLal is stored in the passage or tube it may include an agent for retarding the rate of setting of the material.
  • one or more further anchoring means may be arranged along the length of the tie rod.
  • the thrust member is of generally cylindrical form and may be open-ended. Other forms may be used, for example frusto-conical or conical, but a cylindrical thrust member provides better displace- ment/load characteristics for the device.
  • a thrust member of polygonal, for example hexagonal, form when seen in plan and also open-ended and constructed from plates may represent a practical approximation to a cylinder.
  • the shape of the thrust member in conjunction with the shape of other components of the embeddable anchor may also be determined by the expected direction of application of the load to be supported by the anchor when embedded.
  • the interior of the thrust member may be divided up into cells by dividing walls which may extend radially from the centre line of the thrust member. The dividing walls also act as stiffeners.
  • the thrust member is of open lattice or cellular construction. Such a construction gives a better rigidity/weight ratio.
  • the lattice or cells are so arranged that earth passes through during embeddment which is thus made easier.
  • the lattice or cell size is preferably such that earth becomes packed inside the thrust member and so tends to become retained therein.
  • the thrust member is mounted on the tie rod for relative movement along part at least of the length of the tie rod, the thrust member is releasably secured to the tie rod near to the anchoring means.
  • the thrust member may frangibly be connected to the tie rod, the connection being broken by an explosive charge or may be connected by other releasable means for example explosive bolts.
  • a method using such a thrust member would then include the further step of releasing the thrust member from the tie rod.
  • the thrust member may be released when it has been partially lodged in the earth.
  • the thrust member is frangibly connected to the tie rod so that it can be released from the tie rod by initial driving of the anchoring means which breaks the frangible connection.
  • the thrust member may be completely lodged in the earth by driving the tie rod and anchoring means and the thrust member then released from the tie rod to allow completion of driving of the tie rod and anchoring means.
  • the thrust member may again be connected to the tie rod after the anchor has been fully embedded in the earth. Connection may be achieved by the use of wedging surfaces or by locking means either self-actuating or requiring actuation from a remote point, or by the use of explosive charges which deform the thrust member or a part thereof to lock the member to the tie rod.
  • the anchoring means comprises two plates they may be held together simply by bolts which may be released by explosion or by cutting. The plates can then be held in their expanded condition by forcing binding material into the space below the plates.
  • a linkage is provided which so connects the plates together that they are also held in their expanded condition by the linkage.
  • the linkage may be self-locking to hold the plates in their expanded condition.
  • the present invention further provides a support structure for supporting the anchor during driving, the structure comprising a tower for supporting and/or guiding the tie rod, the tower being secured to a base for positioning the tower on the earth.
  • the tower can have external guides it is preferred if the tower is in the form of a hollow shaft for supporting and/or guiding the tie rod.
  • the support structure may be employed with any of the anchoring devices constructed in accordance with the invention and/or in any of the processes according to the invention.
  • the support structure is particularly useful, however, with an anchor, or in a method which employs an anchor, having a thrust member which is mounted in the tie rod for relative movement along part at least of the length of the tie rod, the thrust member being releasably secured to the tie rod near to the anchoring means.
  • the anchor can be arranged on the said structure with the tie rod supported by tower and with the thrust member disposed beneath the base.
  • the structure is lowered on to the earth its weight (together with the weight of the anchor) can be used to force the thrust member into the earth until the base itself is supported on the earth. Proper positioning of the base on the earth may be assisted by driving the structure.
  • the anchor can then be embedded by driving it into the earth, the thrust member being partially or completely lodged in the earth before it is released from the tie rod.
  • the support structure is designed for use with an underwater hammer, guides being provided on the tower for the hammer.
  • buoyancy chambers may be incorporated, preferably attached to or forming part of, the base, which can be filled with water for lowering and driving and into which air may be pumped, after driving has been completed, to allow the support to be lifted from the sea bed.
  • a first embodiment of the invention comprises an embeddable anchor indicated generally by reference 1.
  • the anchor has a tie rod 2 in the form of a hollow shaft or tube to the lower end of which is secured anchoring means 3 shown in Fig. 1 in a closed position.
  • a thrust member 5 Movable relatively to the tie rod 2 between the anchoring means 3 and a flange 4 secured at the upper end of the tie rod is a thrust member 5.
  • the thrust member 5 comprises a lower part 6 0 f cylindrical form with a series of internal ribs 7 extending from a central hollow tube 8 through which the tie rod 2 extends as shown in Fig. 1.
  • the tube 8 extends only partly through the cylinder, the lower edges of the ribs 7 thus being angled as shown.
  • Alternate ones of the ribs 7 extend upwardly from the lower part 6 and support the upper part of the tube 8 to whose upper end is secured a flanged collar 9.
  • the upper ends of the other ribs 7 are flush with the upper edge of the part 6.
  • the ribs 7 divide the interior of the thrust member into a series of cells and also provide a degree of stiffness and rigidity to the cylindrical structure.
  • the lower edges of the ribs 7 and that of the lower part 6 may be formed as cutting edges cr be fitted with such edges to facilitate movement of the member into the earth during an embedding operation as will be described below.
  • the anchoring means 3 comprise two anchor flukes 10. 11 (Fig. 7) with spade-like, flat surfaces 12, 13, each with integral ribs 14 located within a recess formed by the flat surface and two further parallel ribs 15 joined at their lower ends by a transverse wall 16 whose lower surface is bevelled and wedge-shaped as can be seen from Figs. 3 and 4. As can be seen from Figs. 3 and 4 the ribs 14 and 15 extend for a short distance beyond the upper edges of the surfaces 12, 13.
  • ribs 14 there are three ribs 14 in side-by-side, spaced parallel relationship, the two outer ribs being formed with gear teeth 17 on an arcuate upper surface of the ribs. At their lower ends, the ribs 14 are joined by a spindle 18.
  • each surface 12, 13 is pointed and bevelled as indicated at 20, the bevel in the centre of the lower edge being extended, at 21, to meet the lower edge of the transverse member 16.
  • the two flukes are pivotally attached to a hinge block 22 (Figs. 5 and 6) by means of bolts 23, 24 respectively which pass through holes 25, 26 respectively in the upper parts of the ribs 14 and 15 and also through corresponding holes 27, 28 in each of four mounting arms 29 extending from the base 30 of the block 22.
  • the hinge block 22 is fixed to the lower end of the tie rod 2.
  • a lock bar 31 Extending downwardly from the base 30 of the tie block 22 and centrally between the flukes 10, 11 is a lock bar 31 to whose lower end plates 31a are welded to support a transverse pin 32 on which are pivotally mounted the lower ends of links 33 whose other ends are pivotally attached to the spindles 18.
  • the lock bar 31 passes through an aperture 34 in the base 30 of the hinge block 22 and through a pair of wedges 35 movable with the lock bar 31 with respect to a second pair of co-operating wedges 36 secured to the base 30.
  • a spine assembly comprising parallel plates 37 joined at their upper ends to the outer arms of the arms 29 of the hinge block and at their lower ends to a transverse plate 38, the lower parts of the plates 37 being enlarged to facilitate attachment of the plate 38.
  • the transverse members 16 of the flukes are apertured at 39 to receive an explosive bolt (not shown) of conventional form designed to resist a predetermined tensile load and to break clearly at a shear notch located on the stem of the bolt.
  • the tie rod 2 may be of Grade 50 steel fully welded at its lower end to the base 30 of the anchor bloc ⁇ itself a mild steel annealed casting.
  • the thrust member and its ribs 7 may be fabricated from mild steel plate.
  • the flukes 10, 11 may also be mild steel annealed castings as is the hinge block 22.
  • the links 33 may be of high tensile steel as may be the anchor lock.
  • a ring bolt or other suitable securing means (not shown) is attached to the upper end of the tie rod 2 or to the thrust member to enable a mooring cable or chain to be secured to the anchor.
  • the thrust member 5 is movable relatively to the tie rod 2 and can be located in a position adjacent the flukes so that it can act as a template which guides the tie rod during the initial stages of embedding the anchor in the earth. If desired, the thrust member may be temporarily fixed to the tie rod in the position just described, the fixing being broken during the internal movement of the tie rod.
  • Fig. 10 shows in diagrammatic form only, the anchor in position on the sea bed prior to the commencement of an embedding operation.
  • the anchor with the thrust member 5 in the position shown in Fig. 10 is hoisted over the side of a barge 39.
  • the upper end of the tie rod 2 is connected to a detachable, extension driving shaft 41 of an underwater hammer 42. The whole system is then lowered to the sea bed.
  • the weight of the device forces the thrust member 5 into the top layer(s) of the sea bed material. To facilitate entry of the thrust member 5 it may have a lower cutting edge 43.
  • the device is now in the position shown in Fig. 11.
  • the hammer 42 is now used to drive the tie rod 2 into the earth, the thrust member 5 serving to guide the tie rod 2 during its downward movement. If the thrust member 5 is attached to the tie rod 2 initial driving of the latter shears this connection so that the tie rod 2 is then free to pass through the thrust member 5.
  • the explosive bolt holding the flukes 10, 11 together is fired just before the anchor reaches its final position and the further movement of the anchor into that position opens the flukes.
  • the opening movement of one fluke is synchronised with that other because the gear teeth 17 on the ribs 14 move into meshing engagement and thereafter the flukes move in unison.
  • the flukes are locked therein by the anchor lock mentioned above, the links 33 being in a straight line configuration.
  • the thru ⁇ . member 5 could be driven at least partly into the sea bed before the driving of the tie rod commences. It is possible to drive the thrust member into its final lodgement position in the sea bed before driving of the tie rod commences. This method may be adopted in cases in which the apparatus for embedding the anchor is not sufficiently powerful to drive both thrust member and tie rod at the same time.
  • the anchor is required to resist loads which are applied to the anchor from one side only i.e. loads which are substantially lateral and do not contain any substantial uplift load i.e. a load applied in such a direction that there is an uplift force on the anchor tending to lift it from the ocean bed.
  • the anchor comprises, basically, merely a rod on which the thrust member is mounted.
  • the form of the thrust member will be determined by the factors referred to above, and for example, a thrust member of the form of the member 5 shown in Fig. 1 may be employed.
  • the thrust member may be permanently fixed to the tie rod or it may be movable along at least a part of the length of the tie rod. As described above, the thrust member may be detachably fixed to the tie rod so as to be movable therewith when required and, once the connection between the thrust member and the tie rod is broken, relative movement between these two components can then take place.
  • the anchor may take a form comprising the tie rod 2 (Fig. 1) with a thrust member of the form shown in Figure 1, the lower end of the tie rod being pointed as indicated by the dotted line 52 to facilitate movement of the tie rod into the earth, the anchoring means 3 being absent.
  • the thrust member be movable along the tie rod.
  • the member may be secured permanently at some point along the length of the tie rod, for example at the upper end adjacent the flange 4.
  • Choice of the dimensions of the anchor and of its component parts, for example, the thrust member, and the depth to which the components are buried are embedded will depend upon the nature of the earth in which the anchor is to be embedded, the magnitude of the load to be applied to the anchor and its direction of application.
  • the shape of the thrust member in conjunction with the shape of the other components of the embeddable anchor may also be determined by the expected direction of application of the load.
  • a frusto-conical or cylindrical thrust member has the advantage that it will withstand load from any direction and over a wide range of inclination.
  • a thrust member of polygonal, for example hexagonal, form when seen in plan and constructed from plates may represent a practical approximation to a cylinder.
  • the thrust member may be made in two or more parts and subsequently assembled round the tie rod. Where the load is from a given direction only and with a particular inclination a simpler form of thrust member, for example a plate or sheet form, may be adopted.
  • the size and shape of the components of each such anchor may also be determined, at least in part, by the number of such anchors and the disposition of each anchor relative to the structure.
  • the shape of the thrust member may be determined by the factors just mentioned.
  • An embeddable anchor embodying the invention comprises a tie rod whose length is 70 feet and whose diameter is 3 feet which has, at one end, a cylindrical thrust member of 25 feet diameter and 12 feet depth, and, at the other end, and anchoring means about 10 feet long and providing flukes having a horizontally-projected area of 80 sq. ft..
  • Such an anchor buried vertically in clay to a depth such that the upper surface of the thrust member is about 25 feet below the surface of the sea bed is calculated to have an ultimate load capacity in the upward direction of 2003 tonf approximately in the short term and about 1595 tonf in the long term, and in the horizontal direction a long term capacity of about 960 tonf.
  • the ultimate load capacity is 1598 tonf approximately.
  • the corresponding values are, in the upward direction, about 3737 tonf for both short and lonq term, about 1467 tonf in the horizontal direction, and about 1967 tonf for the cyclic load.
  • the anchor is buried vertically in stiffer clay to a depth such that the upper surface of the thrust member is buried about 10 feet below the surface of the sea bed is calculated to have an ultimate load capacity in the upward direction of 2830 tonf approximately in the short term and 2019 approximately tonf in the long term, ard, in the horizontal direction a long term capacity of 1642 tonf approximately.
  • the ultimate load capaci.ty is about 2014 tonf.
  • the corresponding values are about 2795 tonf for both long and short term, about 800 the horizontal direction, and about 1381 for the cyclic load.
  • the major components of the anchor i.e. the thrust member, tie rod and flukes may be fabricated separately in a range of sizes from which can be assembled an anchor capable of dealing with a specified loading or range of loadings in a specified direction or range of directions and in a specified soil structure.
  • the anchoring means i.e. the flukes contribute substantially to the resistance offered by the anchor to upward movement whilst the thrust member provides a substantial part of the resistance offered by the anchor to lateral movement.
  • the composite mass of the thrust member together with its frictional resistance to movement also contribute to the resistance offered by the anchor to upward movement.
  • the anchor may have one or more additional anchoring means which may be of a construction similar to that of the means 3 described above. Such additional anchoring means will be secured to the tie rod at a point spaced from the lower end of the tie rod.
  • the step of embedding the anchor into the earth may be replaced or supplemented by forming a substantially vertical hole in the earth and locating the anchor in the hole.
  • the depth of the hole may be determined by the nature of the terrain through which it is formed. For example, a hole may be pre-formed through a rocky layer overlying sub-soil into which the anchor can be driven. In this case, the depth of the hole is less than the overall length of the anchor. If necessary, the base of the hole may be under-reamed to allow outward movement of the flukes.
  • the anchor may also be embedded at a desired location by means of a piling rig. If the location is on the sea bed, the rig is conveyed to the location by a barge or ship and is then lowered over the side on to the sea bed. Alternatively, the rig may be launched from a substantially horizontal position on a deck of the barge or ship into a vertical position and then lowered to the sea bed.
  • the rig may be accommodated in a special hold in a ship adapted to carry out anchor embedding operations.
  • the rig is lowered to the sea bed through an access opening in the hull of the ship.
  • Figs. 12 and 13 are a side elevation and plan respectively of one form that the piling rig might take, the rig and associated components being shown in diagrammatic form only.
  • the rig comprises an open lattice tower 44 supported by three legs 45 each pivotally mounted upon the tower 44.
  • the lower ends of the legs 45 are fitted with shoes 46 which may include levelling devices to locate the tower 44 in a vertical position.
  • the driving mechanism for a hammer 47 to which reciprocating movement is imparted via a cable 48 from the driving mechanism.
  • a lifting cable 49 secured to the upper end of the tower 44 enables the rig to be lowered into a desired location.
  • the hammer 47 is guided by guide surfaces on the tower 44 and applies blows to the anchor 1 via a driving follower 50 that allows the anchor to be embedded below the surface if required.
  • the follower extends upwardly within the hammer because this improves the stability of the hammer action.
  • the upper end of the follower is fitted with a protective helmet and interposed between the helmet and the end of the follower is a timber "cushion".
  • the cushion is found to reduce somewhat the peak value of the hammer impact but it also increases the duration of the impact and this gives quicker driving. The cushion also reduces distortion of the upper end of the follower.
  • the follower is not essential and hammer blows could be imparted to the shaft directly or through the protective helmet and timber cushion just described.
  • the piling rig is used in the conventional manner having been conveyed to the desired location and placed in position at the anchor site. When the anchor has been embedded, the rig is withdrawn for use in another embedding operation.
  • the rig may, if desired, incorporate buoyancy tanks which enable the rig to be floated to a desired location at sea. When the location is reached, the tanks are flooded and allow the rig to sink to the sea bed. The rig may be floated in a horizontal position and, at the location, the tanks are selectively flooded to bring the rig into a vertical orientation either before or during the sinking operation. When the anchor has been embedded, the tanks are filled with air to facilitate return of the rig to the surface.
  • the anchoring means may take forms other than the flukes described above.
  • a hollow bulb may be attached to the lower end of the tie rod, the interior of the bulb communicating with the interior of the tie rod 2.
  • the bulb is formed with lines of weakness defining a series of two or more prongs which may be of fluke-like form.
  • the bulb is shaped to facilitate its movement into the earth during an embedding operation. When a required depth of embeddment is reached, the bulb is fractured along the lines of weakness and the prongs splayed outwardly into the adjoining soil.
  • the fracturing and splaying out may be accomplished by an explosive charge inside the bulb, or by pumping a fluent substance down the tie rod into the bulb.
  • the substance may be liquid concrete, liquid mortar or an epoxy resin.
  • the fluent substance may be contained within the bulb and/or tie rod and pressurised to effect fracturing of the bulb and release of the substance which then sets to form a solid mass round the prongs and thus an effective anchoring means.
  • the substance may be pumped down into bulb via a supply line connected either directly to the bulb or to the tie rod.
  • Splaying-out of the prongs could be effected in part by an explosive charge and in part by movement of fluent substance into the bulb.
  • an explosive charge could be used to fracture the lines of weakness in the bulb without causing any substantial movement of the resultant prongs, that movement being effected by the fluent substance.
  • Fig. 14 shows schematically an anchor after the anchor has been embedded and the bulb fractured to produce splayed-out prongs 50 and fluent substance has been pumped into the bulb to form a mass 51 round the prongs.
  • the fluent material may be an aggregate which is forced out to fracture the bulb and so form the prongs, grout is then pumped down into the voids in the aggregate to form a solid mass round and within the prongs.
  • a fluent binding substance could be used in conjunction with the fluke-like anchoring means of the anchor described above with reference to Figs. 1-9.
  • the anchor may be so constructed as to facilitate its removal from the earth when it is no longer required. This may involve providing means for retracting the flukes to the closed position in the case of the anchor described above with reference to Figs. 1-9.
  • the anchor may be dragged from the earth by the application of a suitable force.

Landscapes

  • Engineering & Computer Science (AREA)
  • Structural Engineering (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • General Life Sciences & Earth Sciences (AREA)
  • Mining & Mineral Resources (AREA)
  • Paleontology (AREA)
  • Civil Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • Ocean & Marine Engineering (AREA)
  • Piles And Underground Anchors (AREA)
EP79300273A 1978-02-28 1979-02-21 Ancre de fond et méthode pour enfoncer un tel ancre Withdrawn EP0004150A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB797178 1978-02-28
GB797178 1978-02-28

Publications (1)

Publication Number Publication Date
EP0004150A1 true EP0004150A1 (fr) 1979-09-19

Family

ID=9843300

Family Applications (1)

Application Number Title Priority Date Filing Date
EP79300273A Withdrawn EP0004150A1 (fr) 1978-02-28 1979-02-21 Ancre de fond et méthode pour enfoncer un tel ancre

Country Status (10)

Country Link
EP (1) EP0004150A1 (fr)
KR (1) KR830000610A (fr)
AU (1) AU525572B2 (fr)
BE (1) BE68T1 (fr)
CA (1) CA1145204A (fr)
DE (1) DE2952973A1 (fr)
FR (1) FR2460837A1 (fr)
GB (1) GB2043141B (fr)
NL (1) NL7915020A (fr)
NO (1) NO152202C (fr)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1997014609A1 (fr) * 1995-10-19 1997-04-24 A.S Selantic Systeme d'ancre
WO2010135147A2 (fr) * 2009-05-18 2010-11-25 Moshe Meller Système d'ancrage pour ancrer une base qui supporte une turbine éolienne
CN102673738A (zh) * 2012-05-22 2012-09-19 淮海工学院 自动垂直树根锚
CN115094899A (zh) * 2022-06-21 2022-09-23 中国建筑第七工程局有限公司 一种用于基础施工的可循环式钢板模板及施工方法

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2122236B (en) * 1982-03-30 1986-03-19 Lipsker Eng Ground anchor

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3228153A (en) * 1962-07-02 1966-01-11 Harvey Aluminum Inc Explosive actuated anchor
US3343313A (en) * 1963-01-15 1967-09-26 Harvey Aluminum Inc Apparatus for installing cemented anchors
US3621805A (en) * 1970-02-02 1971-11-23 Us Navy Embedment anchor
US3962837A (en) * 1974-10-11 1976-06-15 Sero Samuel J Apparatus for expandably engaging the walls of an earthen hole
US3969853A (en) * 1975-02-03 1976-07-20 Foresight Industries Torque fin anchor

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1927087A1 (de) * 1968-11-29 1970-06-25 Sanji Genma Erdzuganker
DE2311385C3 (de) * 1973-03-08 1979-03-29 Mituo Kawasaki Kanagawa Shibata (Japan) Verankerungsvorrichtung und Verfahren zum Einsetzen der Vorrichtung in den Boden
IT1016480B (it) * 1974-03-14 1977-05-30 Micoperi Spa Piattaforma marina autosollevabile con struttura sommersa di irrigidi mento
US3962937A (en) * 1974-07-18 1976-06-15 Miller Leo C Error adjustment method and structure for lathes and the like
DE2649693C3 (de) * 1976-10-29 1982-02-25 Hikoitsu Tokyo Watanabe Erdanker sowie Verfahren zum Eintreiben und Lösen desselben

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3228153A (en) * 1962-07-02 1966-01-11 Harvey Aluminum Inc Explosive actuated anchor
US3343313A (en) * 1963-01-15 1967-09-26 Harvey Aluminum Inc Apparatus for installing cemented anchors
US3621805A (en) * 1970-02-02 1971-11-23 Us Navy Embedment anchor
US3962837A (en) * 1974-10-11 1976-06-15 Sero Samuel J Apparatus for expandably engaging the walls of an earthen hole
US3969853A (en) * 1975-02-03 1976-07-20 Foresight Industries Torque fin anchor

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1997014609A1 (fr) * 1995-10-19 1997-04-24 A.S Selantic Systeme d'ancre
WO2010135147A2 (fr) * 2009-05-18 2010-11-25 Moshe Meller Système d'ancrage pour ancrer une base qui supporte une turbine éolienne
WO2010135147A3 (fr) * 2009-05-18 2011-03-17 Moshe Meller Système d'ancrage pour ancrer une base qui supporte une turbine éolienne
CN102673738A (zh) * 2012-05-22 2012-09-19 淮海工学院 自动垂直树根锚
CN102673738B (zh) * 2012-05-22 2014-08-13 淮海工学院 自动垂直树根锚
CN115094899A (zh) * 2022-06-21 2022-09-23 中国建筑第七工程局有限公司 一种用于基础施工的可循环式钢板模板及施工方法

Also Published As

Publication number Publication date
FR2460837B1 (fr) 1984-04-06
NL7915020A (nl) 1980-05-30
NO790659L (no) 1979-08-29
BE68T1 (fr) 1980-05-16
NO152202C (no) 1985-08-21
AU4461879A (en) 1979-09-06
FR2460837A1 (fr) 1981-01-30
AU525572B2 (en) 1982-11-11
GB2043141B (en) 1983-01-26
KR830000610A (ko) 1983-04-16
GB2043141A (en) 1980-10-01
NO152202B (no) 1985-05-13
DE2952973A1 (de) 1980-11-20
CA1145204A (fr) 1983-04-26

Similar Documents

Publication Publication Date Title
KR102252116B1 (ko) 해저 지지 유닛 및 천수 천공 터미널을 제공하는 방법
US3754403A (en) Offshore marine structure embodying anchor pile means
EP2171159B1 (fr) Dispositif et procédé pour une structure de tour marine
US20100150660A1 (en) Offshore oil production platform
US3466878A (en) Rig for work at sea,in lakes,lagoons
EP0972114B1 (fr) Systeme d'ancre penetrante et son utilisation
US20130272796A1 (en) Modular Relocatable Offshore Support Tower
US3213629A (en) Apparatus and method for installation of a pile-jacket assembly in a marine bottom
US6106199A (en) Pile for anchoring floating structures and process for installing the same
US3537268A (en) Marine station and method for fabricating the same
US3624702A (en) Offshore platform support
US3054268A (en) Structure with underwater foundation
EP0004150A1 (fr) Ancre de fond et méthode pour enfoncer un tel ancre
US4721416A (en) Submersible offshore drilling and production platform jacket
CA1226742A (fr) Tour et plate-forme mobiles pour le forage en milieu arctique
US4351624A (en) File and jacket construction method and apparatus
CN112092980A (zh) 一种基于平板锚受力形式的新型鱼雷锚
EP0059648A1 (fr) Méthode et dispositif pour ancrer des constructions off-shore
CN114319331B (zh) 一种水下管桩式基础的施工方法及水下管桩式基础
US3805534A (en) Slide resistant platform anchor conductor silo
CN111005396A (zh) 一种钢围堰安装工艺
GB1563107A (en) Piling
KR840000500Y1 (ko) 매 립 식 닻
AU725166B2 (en) Position penetrated anchor system
US2935854A (en) Offshore drilling platform

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

AK Designated contracting states

Designated state(s): BE DE FR GB IT NL SE

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: THE APPLICATION IS DEEMED TO BE WITHDRAWN

18D Application deemed to be withdrawn
RIN1 Information on inventor provided before grant (corrected)

Inventor name: HARVEY, ROGER CORIN

Inventor name: BURLEY, ELDON