Classifications

• • E—FIXED CONSTRUCTIONS
  • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
  • E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
  • E02D3/00—Improving or preserving soil or rock, e.g. preserving permafrost soil
  • E02D3/12—Consolidating by placing solidifying or pore-filling substances in the soil
• • 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
  • E02D5/808—Ground anchors anchored by using exclusively a bonding material
• • E—FIXED CONSTRUCTIONS
  • E21—EARTH OR ROCK DRILLING; MINING
  • E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
  • E21B7/00—Special methods or apparatus for drilling

Definitions

• the invention relates to the field of the construction of anchorages in the ground, and in particular that of the construction of tie rods.
• the invention will find particular application in the manufacture of tie rods of medium capacity, more particularly made in soft ground.
• a anchor is a device capable of transmitting the traction forces applied to it to a soil layer by resting on a reaction mass constituting the structure to be anchored.
• An anchor usually consists of:
• An object of the present invention is to solve the aforementioned drawbacks by proposing a method of manufacturing an anchor providing better sealing of the reinforcement in the ground.
• the invention relates to a method of constructing an anchoring in a soil, in which:
• an armature and a drilling machine which comprises:
• a drilling tool which is rotatable about a longitudinal axis, the drilling tool being provided with a deployable mixer device which has a retracted position and an extended position, the mixing device having in the deployed position a diametral span which is greater than at its diametric span in the retracted position; a device for injecting at least one fluid into the soil;
• a mixing step is performed during which the mixing device is brought into the deployed position and the drilling tool is rotated with the mixing device in the deployed position, while axially displacing the drill bit along the drilling direction , and while injecting the fluid so as to perform a mechanical in situ mixing of the soil in place with the fluid, so as to form in the soil, below the upper portion, a bulb having a second diameter which is greater than first diameter;
• an insertion step is performed during which the reinforcement is inserted into the bulb, whereby an anchorage is obtained in the ground.
• the implementation of the method according to the invention thus makes it possible to obtain an anchoring in the ground which comprises an upper portion having a first diameter, and a bulb of substantially cylindrical shape having a second diameter greater than the first diameter.
• a deployable mixer device ensures the diameter of the bulb.
• drilling machine one can for example use the tool described in EP 1878833, EP 2931979, ES 2402975 or JP 11222846.
• the step of mixing the soil in place with the fluid can be carried out by moving the drill bit according to the drilling direction in a first direction, in a second direction opposite to the first direction, or alternatively in the two directions. meaning.
• the mixing step is performed during a descent phase and / or a raising phase of the drilling tool.
• the fluid is a binder, so that the bulb comprises a first material forming a mixture of the soil mixture in place with the binder.
• the step of introducing the drill bit into the soil is accompanied by the injection of a drilling fluid, for example water.
• the anchor is a anchor
• the upper portion is the free portion of the tie
• the bulb is the sealed portion of the tie rod.
• the frame is then attached to an anchor head.
• the difference in diameter between the free portion and the sealed portion substantially improves the sealability of the tie rod.
• the shoulder formed between the bulb and the upper portion advantageously participates in sealing the bulb in the soil.
• the armature is inserted into the bulb after removal of the drill bit.
• the second diameter is at least twice the first diameter. Still preferably, the second diameter is at least three times the first diameter. Still preferably, the second diameter is at least four times the first diameter.
• the second diameter of the bulb is at least 400 mm, while the first diameter of the upper portion is between 100 and 300 mm.
• the bulb has a cylindrical portion terminated by a frustoconical portion connecting the cylindrical portion to the upper portion.
• the length of the bulb depends in particular on the effort to be taken up by the anchoring and the characteristics of the ground, in particular the lateral friction.
• the drilling tool is removed from the ground and, during the insertion step:
• the reinforcement is inserted into the borehole before or after filling the borehole with grout.
• the frame is coated with grout.
• the frame is embedded in a volume of grout that extends at least in the bulb.
• the volume of grout also extends into the upper portion.
• the bulb is drilled while the first material is still fresh.
• the armature is a self-reinforcing armature which is constituted by the drilling device which is used to carry out drilling in the bulb.
• the third diameter is smaller than the first diameter.
• the third diameter is at least equal to the first diameter of the upper portion.
• the first constituent material of the upper portion at the end of the mixing step is substituted by the grout at the end of the filling step.
• An anchorage is thus obtained having an upper portion (possibly wider than the initial upper portion) consisting of grout, this upper portion extending longitudinally in the bulb.
• the grout is chosen so that the friction between the grout and the first material is greater than the friction between the grout and the ground, which allows in particular to reduce the length of the sealed portion relative to a conventional tie rod.
• the invention makes it possible to guarantee a high friction between the reinforcement and the grout.
• the grout is a cement slurry having a cement to water mass ratio (C / E) of the order of 2. It may also be a resin or other hardening product.
• the lateral friction obtained is preferably of the order of IMPa.
• the drilling machine further comprises a tubular element having a diameter and a lower end, the mixing device being shaped to be housed in the tubular element when said mixing device is in the retracted position, the diametric span of the mixing device in the deployed position being greater than the diameter of the tubular element, in which process, during the step of introducing the drill bit into the ground:
• the tubular element is introduced into the soil to the first depth according to the drilling direction;
• the drilling tool is introduced into the retracted position in the tubular element; then, after the step of introducing the drill bit into the ground: the drilling tool is moved axially in the direction of drilling relative to the tubular element so as to move the mixing device under the lower end of the tubular element and then said mixing step is carried out.
• the tubular element makes it easier to insert the mixing device into the ground when it is in the retracted position. It also helps support the ground and ensure the first diameter of the upper portion.
• the mixing device is brought into the tubular element in the retracted position and then, during the introduction step:
• the drilling tool is secured to the tubular element
• the assembly consisting of the drilling tool and the tubular element is rotated and said assembly is moved towards the lower end of the bulb in the drilling direction so as to drill into the bulb; the drilling tool and the tubular element are disengaged;
• the drilling tool is removed leaving the tubular element in the bulb; the reinforcement is inserted into the tubular element;
• the well is filled with grout.
• the tubular element serves both as a guide to facilitate the insertion of the reinforcement in the ground, and also a conduit for feeding the grout into the borehole.
• the tubular element is used to fill the borehole with grout from the bottom, which facilitates filling.
• the armature is an open tube at its lower end to facilitate filling. It can also be a bar attached to a hose or a tube cuffs.
• the tubular element is first introduced into the soil, and then the drilling tool is introduced into the tubular element introduced beforehand into the soil.
• the tubular element is introduced simultaneously into the ground with the drilling tool, the mixing device being previously brought into the retracted position and secured to the tubular element.
• the tubular element is removed at the end of or during the insertion step.
• the step of filling with grout may be performed during removal of the drill bit.
• the drilling tool comprises a tubular body extending along the longitudinal axis
• the mixing device comprises two deployable wings which are pivotally mounted relative to the tubular body, and spring members disposed between the tubular body and each of the deployable wings, the spring means tending to bring the mixing device in the deployed position by pivoting the deployable wings.
• the fluid is injected under pressure during the mixing step.
• An interest is to help the destructuring of the soil and the mixing of the grout with the soil.
• the pressure applied can range from a few kPa up to the high pressures used in jet-grouting, of the order of 60 MPa or more.
• the initial material of the bulb consisting of the soil mixture in place with the fluid is replaced by a sealing material.
• the fluid is a drilling fluid, for example water
• the sealing material is a mortar.
• the substitution step consists of injecting the sealing material into the bulb while discharging the initial material from the bulb.
• fluid injection is continued to evacuate the initial material, after which the mortar is injected.
• the invention also relates to a method of constructing a pre-stressed anchor in a soil bordered by a reaction mass, implementing the method of constructing an anchor according to the invention and in which the step of introduction comprises a preliminary step of drilling the reaction mass, wherein, after obtaining the anchoring, there is a pulling head between the reaction mass and the armature, and then tensioning the armature.
• the reaction mass may be a wall, a raft, or any other structure to be anchored.
• the invention also relates to an anchoring in a soil in which, considered from the surface of said ground, said anchoring extends in a longitudinal direction and comprises successively an upper portion having a diameter, then at least one bulb having a diameter greater than diameter of the upper portion, the upper portion and the bulb having at least one first material, and the anchor further comprises a frame extending in the longitudinal direction in the upper portion and in the bulb.
• the first material consists of a mixture of soil excavated with a binder.
• the proportions of soil and binder within the first material will be chosen according to the type of ground and the objective of resistance of the anchorage. According to one variant, the proportion of soil is less than 10%.
• the reinforcement is coated with a second material according to a coating diameter which is smaller than the diameter of the bulb.
• the coating diameter is at least equal to the diameter of the upper portion.
• the second material is advantageously different from the first material.
• the second material forms a cylindrical coating extending longitudinally in the bulb and in the upper portion.
• the second material is a grout.
• the reinforcement of the anchor preferably comprises a metal bar, a tube or at least one strand.
• the invention finally relates to a anchor comprising an anchor according to the invention.
• FIG. 1 illustrates the step of introducing the drill bit into the ground according to a first embodiment of the method according to the invention
• FIGS. 2 and 3 illustrate the mixing step during which the bulb is formed
• FIG. 4 is a longitudinal sectional view of the soil after removal of the drill bit
• FIG. 5 illustrates the step of insertion of the armature into the bulb
• FIG. 6 illustrates the step of drilling the bulb of a second embodiment of the method according to the invention
• Fig. 7 illustrates the step of filling the borehole of Fig. 6 with grout
• Figure 8 illustrates the step of inserting the reinforcement into the drill hole filled with grout
• FIG. 9 illustrates the anchoring obtained by the implementation of the method according to the second embodiment of the invention.
• FIG. 10 illustrates the step of introducing the drilling tool into the ground according to a third embodiment of the method according to the invention, the drilling tool secured to a tubular element being introduced together into the ground ;
• FIG. 11 illustrates the step during which the drilling tool is disengaged from the tubular element
• Figures 12 and 13 illustrate the formation of the bulb by in situ mixing of the soil excavated with a fluid
• Figure 14 is a longitudinal sectional view of the soil after removal of the drill bit
• Figures 15 and 16 illustrate the insertion of the armature into the bulb and the withdrawal of the tubular element
• FIG. 17 illustrates the bulb drilling step of a fourth mode of implementation of the method according to the invention.
• Figures 18 to 21 illustrate the steps of filling the borehole made in the bulb with a grout, the step of inserting the reinforcement into the filled hole, and the withdrawal of the tubular member;
• Figure 22 illustrates a fifth embodiment of the invention in which the tubular element is secured to the drill bit to be moved in the bulb during drilling of the bulb;
• Figure 23 illustrates the removal of the drill bit, the tubular member remaining in the bulb;
• Fig. 24 illustrates the step of inserting a tubular frame into the tubular member
• Figure 25 illustrates the filling of the borehole made in the bulb by injecting a slurry into the tube
• Figure 26 illustrates the removal of the tubular member.
• Fig. 27 illustrates a tie rod according to the present invention
• Figures 28 and 29 are cross-sectional views of the upper portion and the bulb of the tie rod of Figure 27.
• a drilling machine 10 such as that described in EP 1878833 or EP 2931979.
• This drilling machine 10 which is not described in detail here, comprises a drilling tool 12 which is rotating around a longitudinal axis A.
• the means for driving the rotary drilling tool 12 are known elsewhere, and will not be described here.
• the drilling tool 12 is further provided with a deployable mixer device 14 which has a retracted position illustrated in FIG. 1, and an extended position illustrated in FIG.
• the drilling tool 12 comprises a tubular body 16 extending along the longitudinal axis A; the mixing device 14 comprises two deployable wings 18, 20 which are pivotally mounted relative to the tubular body 16 about an axis of rotation X which is perpendicular to the longitudinal axis A.
• the mixing device further comprises organs springs not shown here, which are arranged between the tubular body 16 and each of the deployable wings 18, 20. In known manner, the spring members tend to lead the mixing device in the deployed position by pivoting the deployable wings about the axis X.
• the mixing device 14 has, in its extended position illustrated in FIG. 2, a diametral span T1 which is greater than its diametric span T2 in the retracted position.
• the drilling machine 10 further comprises a device 22 for injecting a fluid under pressure into the ground.
• the fluid is a binder.
• the injection of fluid into the soil S is via nozzles disposed in the tubular body 16 of the drill bit near the flanges 18, 21.
• a step is made to introduce the drilling tool into the ground in a drilling direction F which is parallel to the longitudinal axis A in order to forming an upper portion C having a height H1, a first diameter D1. As shown in FIG. 2, the upper portion C extends from the ground surface to a first depth P 1.
• the upper portion C has a substantially cylindrical shape having a diameter Dl.
• Dl a diameter
• the mixing device is in the retracted position during the introduction step. It is specified that the diametral span T2 of the mixer device in the retracted position is substantially equal to or slightly less than the diameter D1.
• the drilling tool 12 further comprises a cutting member 13 which is disposed at the distal end of the tubular body 16 below the mixing device.
• This cutting member 13 is configured to drill in the soil S according to the drilling direction.
• a mixing step is carried out during which the mixing device is brought into the deployed position, by deploying the wings 18, 20. Then, one rotates the drilling tool with the mixing device 14 in the deployed position while injecting the binder so as to perform a mechanical in-situ mixing of the soil in place with the binder.
• the drill bit is moved axially along the drilling direction F so as to form a bulb B in the soil, below the upper portion C.
• the bulb B has a second diameter D2 which is greater than the first diameter D1 of the upper portion.
• the bulb B is made from top to bottom, performing the deployment of the wings immediately below the upper cavity.
• the wings could be deployed while the drill bit has reached the depth corresponding to the depth of the lower part of the bulb B.
• the bulb would be formed of low at the top up the drill bit 12.
• the deployment of the wings is performed automatically, so that the bulb B is made from top to bottom by longitudinal displacement of the mixing device in the deployed position and fluid injection.
• the bulb B has a cylindrical shape extending on a height H2. It is understood that the second diameter D2 corresponds to the maximum diameter of the bulb B. Given the particular geometry of the drilling tool 12, the bulb B has, at its lower end Bl, an extension of a diameter smaller than the second diameter D2. The bulb also has at its upper end B2 a frustoconical shape forming the junction between the cylindrical portion of diameter D2 and the upper portion C of diameter D1. This frustoconical shape promotes the sealing of the bulb in the soil.
• an insertion step is then carried out in the course of which a reinforcement 30 is inserted into the bulb B after having withdrawn the drilling tool 12 from the ground.
• the armature 30 consists of a metal bar which is inserted in the drilling direction.
• the anchoring 100 is obtained in the soil extending in a longitudinal direction Z which corresponds to the drilling direction F.
• the step of introducing the drilling tool into the ground, and the mixing step are similar to those of the first embodiment.
• the second mode of implementation differs from the first mode of implementation, in that, after the mixing step, the drill bit is removed from the ground and then, during the step of insertion: K is drilled in the bulb B in the drilling direction F before curing the soil-binder mixture.
• the bore K has a third diameter D3 which is smaller than the second diameter D2 of the bulb B.
• the bore K is made using a drilling device 40 of tubular form whose lower end is open and carries a means of cut 42. As shown in Figure 7, after drilling K, the latter is filled with grout. In this example, the filling with grout is by injection through the drilling device 40, while raising the drilling device.
• the reinforcement 30 is inserted into the bore K, as illustrated in FIG. 8.
• the reinforcement 30 could be inserted in the borehole K before step of filling with grout.
• the grout is cement grout having a ratio cement on water C / E of the order of 2.
• the grout is chosen so that the friction between the frame and the grout is important, of the order of 1 MPa. It is also chosen so that the friction between the grout and the mixture resulting from mixing the soil with the binder is more important than the friction between said mixture and the soil surrounding the anchor.
• the third diameter D3 is also smaller than the first diameter D1.
• the third diameter D3 could be equal to or slightly greater than the first diameter D1 of the upper portion, so as to replace the material constituting the upper portion, namely the aforementioned mixture, with grout. sealing. This variant is particularly illustrated in Figure 22 which will be described in more detail below.
• FIGS. 10 to 15 there is illustrated a third embodiment of the method according to the invention.
• the third mode of implementation of the method is distinguished from the first embodiment described above by the fact that the drilling machine further comprises a tubular element 50 which has a diameter D and a lower end 50a, as well as
• the mixing device is designed to be housed in the tubular element 50 when the mixing device is in the retracted position.
• the diametral span T1 of the mixing device in the deployed position is greater than the diameter D of the tubular element 50.
• the diametral span T2 of the mixer device in the retracted position is less than the diameter D of the tubular element 50.
• the tubular element 50 is introduced into the ground in the drilling direction F having previously disposed the drill bit in the retracted position in the tubular element 50. To do this, one solidarizes the drilling tool 12 with the tubular element 50 and introducing the assembly consisting of the tubular element secured to the drilling tool in the ground in the drill direction, as shown in Figure 10.
• the drilling tool is detached from the tubular element and then descended. axially the drilling tool 12 according to the drilling direction F with respect to the tubular element 50. In this way, the mixing device 16 is moved under the lower end 50a of the tubular element 50, after which it is made In-situ mixing step of the soil excavated with the binder.
• the tubular element 50 surrounds and delimits the upper portion C which is disposed above the bulb B. After removal of the drilling tool 12, the reinforcement 30 is inserted into the bulb in the drilling direction F, after which the tubular element 50 is removed.
• FIGS. 17 to 21 illustrate a fourth mode of implementation of the method according to the invention, which differs from the third mode of implementation in that, after removal of the drilling tool 12 from the ground S, then, during the insertion step: a bore K is made in the upper portion C and in the bulb B in the drilling direction F and in a third diameter D3 less than the second diameter D2. The well is then filled with the grout before the reinforcement 30 is inserted into the bore K. Then, the tubular member is removed from the ground.
• FIG. 22 With the help of Figures 22 to 26, we will now describe a fifth embodiment of the method according to the invention.
• This mode of implementation differs from the third embodiment in that, after the mixing step, the mixing device is brought into the retracted position in the tubular element 50 and then, during step d introduction, the drilling tool 12 is secured to the tubular element 50, and the assembly consisting of the drilling tool 12 and the tubular element 50 is rotated, and said assembly is moved towards the lower end Bl of the bulb B.
• This displacement is operated in the drilling direction F so as to perform a drilling K 'in the bulb B, being recalled that the bulb B is at this time constituted by a fresh mixture resulting from the mixing of the soil excavated with the binder.
• the armature 30 ' is inserted into the tubular element 50.
• the armature 30' consists of an open tube at its lower end 30'a and at its upper end 30'b.
• the tubular element 50 is filled with sealing grout so as to fill the borehole K'. This filling is performed by injecting the grout from the upper end 30'b of the frame 30 'so as to repress the grout from the lower end of the frame. After filling the borehole K 'with the grout, the tubular element 50 is removed from the ground so as to obtain anchoring.
• the frame 30 'could also be a bar or a strand associated with an injection device such as a sleeve tube or more simply a hose. Without departing from the scope of the present invention, the filling could also be carried out during the step illustrated in FIG. 23.
• FIG 27 there is illustrated a anchor 300 having an anchor 200 made using the second, fourth or fifth embodiment of the method according to the invention.
• This anchor 300 is secured to a reaction mass 310 and bordering the ground.
• the reaction mass 310 is a vertical concrete wall.
• the aforementioned introduction step comprises a preliminary step of drilling the reaction mass 310. This drilling is performed in a drilling direction which is inclined relative to the vertical direction so that the longitudinal axis Z of the anchor is inclined relative to the vertical.
• Anchoring 200 is then carried out by implementing the method according to the invention.
• the anchor 200 considered from the surface, comprises successively an upper portion G and then at least one bulb B which has a diameter D2 greater than the diameter D3 of the upper portion P.
• the upper portion G extends along a height H1 while the bulb extends over a height H2. It is specified that the upper portion G is intended to form the free portion of the anchor, while the bulb B forms the sealed portion of the tie rod 300. In the free portion, the friction is substantially reduced by a device 203 , such as a greased sheath, or a frame coated with a non-adherent coating.
• a device 203 such as a greased sheath, or a frame coated with a non-adherent coating.
• the upper portion G forms the upper part of a cylindrical core consisting of grout that extends longitudinally in the bulb B.
• the bulb B consists of an annular layer mixture consisting of a soil-binder mixture surrounding the cylindrical slurry core.
• the anchor 200 further comprises an armature 30, in this case a metal bar of diameter D4, which extends in the longitudinal direction Z in the upper portion G and in the bulb B.
• the cylindrical core slurry coats the frame 30 over more than two-thirds of its length. It is therefore understood that the bulb B consists of a first material resulting from the mixing of the soil excavated with the binder and a second material, in this case the grout, which surrounds the frame 30, the first coating material the second material.
• the diameter D2 of the bulb B is equal to 600 mm, while the coefficient of friction between the first material and the ground is 80 kPa.
• the diameter of the cylindrical core extending inside the bulb B which consists of the second material has a diameter D3 equal to 150 mm, and a coefficient of friction between the first and the second material of the order of 320 kPa.
• the diameter of the armature 30 is 50 mm, and the coefficient of friction between the armature and the second material is of the order of 960 kPa.
• a pulling head 320 is mounted at the upper end of the upper portion G, this pulling head being attached to the reaction mass and to the reinforcement 30. After having placed the pulling head
• the reinforcement 30 is tensioned so as to prestress the anchor 300.

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• Engineering & Computer Science (AREA)
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• General Engineering & Computer Science (AREA)
• Environmental & Geological Engineering (AREA)
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• Physics & Mathematics (AREA)
• Fluid Mechanics (AREA)
• Geochemistry & Mineralogy (AREA)
• Piles And Underground Anchors (AREA)

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• 2016
  • 2016-02-10 FR FR1651052A patent/FR3047496B1/fr active Active
• 2017
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