KR20010022706A - Ground reinforcement or stabilisation method and apparatus - Google Patents

Abstract

The present invention is based on the use of a screw-in anchor element 16 having a shaft 17, a helical wing 18 adjacent the leading end, a helical wing 19 adjacent the trailing end, and a drive coupler 20, Provides a reinforcement method. The anchor elements are screwed into the ground using a leading end disposed in a relatively stable soil and a trailing end disposed in a relatively unstable soil. The wings (18) may be of a larger pitch than the wings (19). The shaft 17 may be hollow. When the shaft 17 is hollow, the shaft may be used to drain liquid or gas from the soil or to inject the activator into the contaminated soil.

Description

[0001] GROUND REINFORCEMENT OR STABILISATION METHOD AND APPARATUS [0002]

Ground reinforcement systems, such as geogrids, metal strips and fabrics, were used to improve the soil properties and behavior. Since these systems are placed in the proper locations during construction, they can only be run on artificial soil structures. For the reinforcement of unfilled natural ground, "soil nail" has been developed in recent years. Soil nail is generally a circular axis with a completely constant dimension. Initially, the soil nail was in the form of a metal reinforcement shaft injected into a circular hole in the ground. Ballistic soil nails have been developed more recently. Ballistic soil nail is a metal reinforcement shaft that has been struck in the ground. The sheep type of soil nail works by either of the following methods:

Attachment of the soil to the axis of the nail; And

Friction between soil and nail shaft

These systems of ground reinforcement suffer some losses. Reinforced geogrids, metal strips and fabrics can only be used in the construction process of artificial soil structures. They can not be used to reinforce naturally occurring structures. Axially shaped soil nails injected into the ground suffer a loss that can take several days to develop and develop the maximum strength of the grouting. Unlike injected soil nails, ballistic soil nails have an immediate effect on insertion, but are limited to a length of up to about 6 m. Since the ballistic soil nail operates by soil adhesion and friction along the axial length, this limitation in the roadside limits its effectiveness.

In other fields, screw-in ground anchors have been known for some time. These anchors typically consist of shafts that carry one or more helical wings. The rotation of the anchor shaft fixes the anchor into the ground. A representative description of such an anchor includes the following patent documents.

U.S. Pat. Nos. 3,011,597 and 3,011,598 to Samuel R. Galloway and William H. Glloway, all published December 19, 1961. This specification relates to landing. It represents a tube open at both ends for transferring one thread.

British Patent No. 1,098,555 of Trefileries Leon Bekaert P.V.B.A. This specification relates to a support suitable for fence support. An open ended tube for transferring one or more threads. When multiple threads are provided, they can form a simultaneous starting thread.

Up to this point, screw-in ground anchors have been used as either tension anchor or foundation anchor. They have not been used in the field of ground reinforcement.

For example, A.B., a subsidiary of Emerson Electric Co., Have been manufacturing screw-in tension anchors for several years to fix the electrical network of the Chance Company (Centralia, Missouri, U.S.A.) and the base of the radio transmission towers.

A.B. Chance Company has also been manufacturing screw-in base anchors for several years. Specially designed for street lighting, these types of anchors are generally made up of at least one helical wing or a hollow iron pipe carrying a threaded end adjacent to one end. The rotation of the pipe fixes the foundation anchor in the ground. The front end of the pipe is open or closed with a formed plate. The other end of the pipe generally carries the plate where the street lighting is bolted. Some other forms of screw-in foundation anchors manufactured by A. B. Chance Company are shown in U.S. Patent No. 4,339,899 (assessed on June 20, 1982).

The present invention relates to the naturally occurring and artificial soil structure reinforcement.

In contrast, the present invention uses a screw-in ground anchor in the field of reinforcing the ground, where the anchor is not normally under tension or compression. The present invention also provides an alternative form of a screw-in ground anchor.

The present invention seeks to provide the following soil reinforcement apparatus.

· Can be placed in a real soil structure

Some objects that are immediately effective in insertion; And

· Easily placed on the soil

The present invention also seeks to provide:

Soil reinforcement methods;

Methods of treating contaminated soil;

Methods of draining the soil structure;

• methods to investigate subsoil status; And

· How to build a well

The present invention provides a ground reinforcement method using a ground anchor having at least one helical wing adjacent to at least one end. According to the method, the anchor elements are arranged from at least one adjacent helical wing at one end and a relatively stable ground to a relatively unstable ground to the other end. If soil movement or sliding cracks occur, the resistance of the anchor elements is shifted to improve the resistance against ground movement or sliding cracks. The anchor resistance is in the form of compression of the shaft tension on the anchor element and on the soil mass. Thereby potentially fixing the sliding soil below a deeper stabilizing structure. The compression supporting on the soil mass is at least partially provided by the spiral wings on the relatively stable ground supported against the ground.

The present invention also provides a method for treating a contaminated soil consisting of disposing a ground anchor element in a ground according to the present invention and injecting the active agent into the ground through the coaxial axis of the anchor element.

The present invention also provides a method for draining soil, comprising disposing a ground anchor element in a ground according to the present invention and draining the water out of the soil through the coaxial axis of the anchor element.

The present invention relates to a method for inspecting the underlayer condition, comprising moving an anchor element with a tip movable into a ground according to the present invention, extracting a sample of undisturbed soil in front of the anchor element It also provides.

In a first form, the device according to the invention may have more than one wing adjacent to one or both ends of the shaft.

The axis can be empty.

When the shaft is empty, the leading end of the shaft may be provided with a tip that prevents the soil from blocking the shaft.

When the present invention is used to drain the soil, the anchor member is an electrode that addresses the electrical field to provide an electroosmotic effect that enhances the movement of moisture through the soil, or it is particularly preferred to transport the electrode.

When the shaft is empty, it can drill holes or allow porous tips to penetrate moisture from the soil mass. When holes in the shaft are pierced, it is preferred to fill the shaft with a porous material to prevent penetration of the soil.

The axis of the anchor element according to the invention is:

Steel or other metals;

High tensile plastic material; or

Concrete reinforced with steel or other reinforcement

.

In the method of ground reinforcement according to the invention, it is preferred that the compression to support on the soil mass is provided by the spiral wing of the ground anchor element according to the invention. However, in some applications of the method according to the invention, the compression may be provided at least partially by means of a spiral wing adjacent one end of the shaft and by other means adjacent the other end of the shaft. In one particularly preferred form of the method, where the exposed surface is accessible, the other means take the form of a substantially flat plate.

The specific embodiment of the anchor element and the method according to the invention will now be explained by way of non-limiting example with reference to the accompanying drawings.

Brief Description of Drawings:

1 is a longitudinal sectional view showing a ground reinforcement method and apparatus according to the prior art;

Figure 2 is a side view of the ground anchor element according to the invention;

3 and 4 are vertical sectional views showing the method of reinforcing the ground according to the present invention

5 is a side view of the ground anchor element according to the present invention;

6 is a longitudinal sectional view showing a ground reinforcement method and a ground anchor element according to the present invention;

7 is a longitudinal sectional view showing a method of reducing ground water and a method of reinforcing the ground according to the present invention

Figure 8 is a front view of the embodiment of the ground anchor according to the invention, particularly adapted for use in a corrosive state;

9, 10 and 11 are vertical sectional views showing the method and apparatus of the present invention for stabilizing the existing structure

12 is a longitudinal section of the use of the apparatus and method according to the present invention for restoring defective soil structures;

13 is a longitudinal section of an apparatus according to the invention for sampling soil conditions;

14 is a longitudinal sectional view of the apparatus according to the present invention used for well construction;

Detailed Description of Embodiments:

Figure 1 shows the use of prior art soil nails as soil reinforcement. In this figure, the embankment 2 has exposed sloped tops 3 and roads 4 at the top 7 of the embankment. Geomechanical destruction of the same structure as the bank 2 is liable to occur due to sliding of the soil mass 8 along the circular surface 9 as shown in the longitudinal sectional view shown. The initial failure can be caused by the rotation of the soil mass 8, such as a cohesive structure for the point 11, which is the center point of the arc defining the surface 9.

The soil nails (12), (13) and (14) were arranged in the direction from the direction of the exposed surface (3). When the soil mass 8 is in equilibrium, there is no resulting pressure applied by the soil in the longitudinal direction of the nail. When the soil mass 8 begins to move, there is soil adhesion on the surface of the nail and there is friction between the soil and the nail surface. The resulting adhesion and frictional forces force the nails along the length into the tension and prevent the soil mass 8 from moving.

Figure 2 shows a screw-in soil anchor element 16 with a shaft 17 and wings 18, 19 adjacent each end. The element 16 is made of heat-plated galvanized iron, black iron or other suitable material. The vanes 18 and 19 are substantially helical and are welded to the shaft 17. The shaft 17 has a substantially constant diameter through the length between the blades 18 and 19. The coupler 20 moves the torque of a known method in a known drive element not shown in the figure. The application of rotation to the end of the shaft towards the coupler 20, with the screw-in ground anchor element being installed, allows the anchor element to enter the ground in a known manner of the screw. The vanes 18 and 19 have the same pitch or different pitches. When the wings are not at the same pitch, rotation of the anchor element causes each wing to enter a different distance into the soil, causing either compression or tension on the axis 17 between the wings 18 and 19 easy to do. The entry of the anchor element into the soil can be chosen differently in that it causes soil compression between the two wings. This compressive preload changes the soil characteristics and increases the stabilizing effect of the anchor elements.

It has been found that the dimensions of the anchor elements should be within the following ranges and are convenient:

Shaft Diameter, 60mm - 220mm

Wing diameter, 150mm - 600mm

Wings spaced along an axis at least 2.5 times the wing diameter; And

Typically the wing pitch is 1/3 of the spiral wing diameter

The configuration and arrangement of the anchor elements according to the invention occupy a specific position. In other words, the dimensions, number and arrangement of anchor elements depend on location and are determined by the use of standard engineering techniques.

The present invention can be used to support steep excavation, to improve slope stability and to improve the transportability of the ground.

FIG. 3 shows the use of a ground anchor element according to FIG. 2 to support steep excavation. In this figure, a circular ground line 21 was excavated to create a vertical surface 22. The anchor element 23 was secured into the soil 24 in a substantially horizontal orientation to provide a stiffener. If the mass of the soil 24 begins to slip toward the surface 22, the adhesion of the soil to the shaft 17 and the friction between the soil and the shaft 17 can be achieved by a method similar to the operation of prior art soil nails Of the stabilization degree. However, in addition to this adhesive force and frictional force, the movement of the soil in the direction 25 will tend to entrain the shaft 17 which tensions the element 16 tensionfully, (17) will tend to compress the soil mass between the blades (18) and (19). The wings 18 are deeply embedded in relatively stable soils away from the surface 22 to fix the anchor elements in place. Compressive forces acting on the soil moving around the wings (19) will be likely to keep the soil back from the movement.

4 shows a method in which a ground anchor element according to the invention is used in another method of supporting steep slant excavation. In this figure, a circular ground line 26 was excavated to create a vertical plane 27. The anchor element 28 is secured into the soil 29 in a substantially vertical direction to provide a stiffener. In a given structure, the orientation of the anchor elements can be selected for the placement and angle of the necessary stiffeners, and for accessibility for installation.

FIG. 5 shows an alternative embodiment of a ground anchor element according to the invention. The shaft 31 moves substantially three helical blades 32, 33 and 34 adjacent the coupler 35. In effect, the two helical blades 36 and 37 are moved adjacent the end 38 of the shaft 31 far from the coupler 35. When installed in the soil, the two wings adjacent to the end 38 are deeper in the soil structure than the three wings adjacent to the coupler 35. In general, the deeper soil in the structure will be stronger than the soil closer to the surface. Fewer wings will be needed to develop a given support capacity in stronger soils than are needed to develop the same support capacity in softer soil closer to the surface.

In the embodiment of the invention as shown in FIG. 6, the screw-in anchor 40 is additionally provided with control panels 41, 42 and 43. Each control panel is adjacent or attached to the end of the anchor and each control panel is supported against the exposed surface 44 of the excavation. In an embodiment of the invention, the installation of the anchor is adjusted so that the anchor shaft is under an anchor that operates to place a positive compression load on the tension, control panel and soil. Each screw-in anchor element supports the load immediately without delay to the grout (injection) and is installed in a single action. In another embodiment of the invention which is not shown but similar to the sixth embodiment, the screw-in anchor elements are formed by spiral wings or blades similar to (18) adjacent to their sole infiltration ends and (41) - A similar control panel is provided.

FIG. 7 illustrates the use of the present invention to improve the stability of slopes (either natural or artificial) by machine reinforcement and water pressure reduction. In this embodiment, the axis 46 of each screw-in anchor is empty and protrudes from the surface 47 of the sloped surface 38. Water enters the common axis through the porous tip 49 of each axis 46. The porous tip may be made of a suitable material such as sintered bronze or porous ceramic. By providing each screw-in anchor on the slope and by providing a porous tip, the joint axis can be used to provide a deep drainage path within the slope, which improves stability considerably.

In an alternative embodiment of the invention (not shown), water enters the cavity axis through a groove or hole in the surface of the shaft. In this embodiment, the cavity axis preferentially fills the osmotic filtration material to prevent the soil from being washed into the shaft. Suitable osmotic filtration materials include filter paper, geotextile fabric, and sand adhered with an epoxy adhesive.

When the present invention is used to drain the soil, at least one anchor element is an electrode that exhibits the electrical field to provide an electroosmotic effect that enhances the transfer of moisture through the soil, or it is particularly preferred to transport the electrode.

Further, another embodiment of the present invention is useful in a ground condition where a problem arises due to the corrosion of the shaft of the reinforcing element.

FIG. 8 shows one such embodiment. This figure shows an anchor element 51 with a single wing 18. The wing 18 is not welded to the shaft but instead is welded to the pilot portion 52 that is detachably connected to the drive tool 53 in the form of a turn. The tee bar or reinforcement bar 54 enters under the cavity of the drive tool 53 and is connected to the pilot portion 52. The tee bar or reinforcement bar 54 may be made of any suitable material, such as steel or high elongation pearl tough plastic material. The anchor element 51 is screwed into the ground in a conventional manner. Depending on how hard the soil is, the drive tool 53 may or may not be removed. If the drive tool 53 is hard enough not to fall into the resulting displacement space when the soil is removed, the drive tool is removed and the grouting is pumped into that space to fill the derivation space. If the soil is not hard enough not to fall, the drive tool is not removed and the grouting is pumped down into the cavity of the drive tool to fill the space between the bar 54 and the drive tool 53. Once the grouting has been corrected, the anchor element is composed of blades 18 rigidified by reinforced concrete rods. 6 is attached to the end of the anchor element remote from the helical vane 18. [

FIG. 9 shows the use of a screw-in anchor 55 to reinforce the foundations 56 of new or existing construction.

FIG. 10 similarly shows the use of a screw-in anchor 57 to enhance the foundation under the dikes or large tanks 58. The anchor 57 can be installed during construction or installed as a re-installation.

FIG. 11 illustrates how an embodiment of the present invention can be suitably used in a foundation of an existing configuration without having to physically confront the existing configuration. The figure shows a " lean " structure 61 due to differential compression of the underlying soil. The anchor elements 62, 63 and 64 are shown on one side of the structure in which the soil is most compressive. In the embodiment of the invention as shown in FIG. 11, the load of the anchor elements 62, 63 and 64 is a compressive load.

12 shows a vertical section of the use of the apparatus and an apparatus and method according to the invention for restoring a defective soil structure. FIG. 12 shows a soil structure with defects due to slip failure along a rounded surface 67 in the vertical section shown. The anchor element 68 according to the present invention is disposed in the structure 66 and has an end projecting from the surface 67. [ These projecting ends are attached to the reinforcement mesh 69 lying on the surface 67. A filler (70) is placed on the reinforcement mesh (69) to form a surface (71). Another anchor element 73 according to the present invention is inserted into the structure 66 through the filler 69 and has one end projecting from the surface 71. The projecting end is attached to the reinforcement mesh 72 which is placed on the surface 71. The surface 71 and the reinforcement mesh 72 are sprayed with a thin layer of concrete.

Another suitable embodiment according to the present invention provides an investigation of the ground condition. One such embodiment is shown in FIG. The anchor element 75 of FIG. 13 has a cavity axis 76 with an open leading end 77. The shaft 76 has a helical wing 18 adjacent the leading end 77. A removable rod 78 attached with a sealing plug 79 extends the length of the shaft 76. To sample a soil condition, an anchor element 75 with a rod 78 attached with a sealing plug 79 is inserted into the soil. At a suitable depth, the rod 78 and the plug 79 are removed and the soil in front of the anchor element 75 is harvested. The rod 78 and plug 79 will then be replaced and the anchor element will be pushed deeper into the soil to take another soil sample.

Other embodiments of the apparatus and method according to the present invention are provided for the formation of wells. One such embodiment is shown in FIG. 14. This figure shows an anchor element 81 with a single vane 18. [ The wing 18 is not welded to the shaft and instead the turn is welded to the removably welded pilot portion 82 in the drive tool 83 in the form of a coaxial shaft. The well-liner 84 extends the length of the anchor element 81. In use, the anchor element 81 with the well-liner 84 is inserted into the ground at an appropriate depth. The drive tool 83 is then removed from the ground and separated from the pilot portion 82 leaving only the well-liner 84.

Claims (31)

A ground reinforcement method using an anchor element comprising a shaft having a leading end and a trailing end, the anchor element comprising at least one actual top helical wing adjacent the leading end, Placing an anchor element within a ground that is to be reinforced with said trailing end of said shaft in a relatively stable ground and at least one said leading end of said shaft adjacent a substantially helical wing and a relatively unstable ground Wherein the soil reinforcement method comprises the steps of: 2. The method of claim 1, wherein the anchor element comprises at least one actual top helical wing adjacent the trailing end of the shaft. 3. The apparatus of claim 2, wherein at least one wing adjacent the leading end of the shaft and at least one wing adjacent the trailing leg portion of the shaft are configured to engage the leading end of the shaft with the leading edge of the shaft when the anchor element is screwed into the ground. And the soil is compressed at a different pitch to cause the soil to compress between the trailing end portions. The method of any one of the preceding claims, wherein the shaft is hollow. 5. The method of claim 4, wherein the leading end of the shaft is provided with a tip to prevent the soil from clogging the cavity axis. 6. The method of claim 5, wherein the tip is removable. 7. The method according to claim 5 or 6, Wherein the tip is porous to allow osmosis of liquid into the cavity axis. 8. A method according to any one of claims 4 to 7, wherein the shaft is perforated to allow the flow of liquid into the cavity axis. The method of any one of the preceding claims, wherein the anchor element is an electrode for electro-osmosis. The method of any one of the preceding claims, wherein the anchor element has an electrode for electro penetration. A method according to any one of the preceding claims, wherein the anchor element is attached to the shaft closest to its trailing end and comprises a plate adapted to apply a compressive load to the adjacent exposed surface. And at least one substantially top helical wing adjacent the leading end of the shaft, the helical wing including a shaft having a leading end and a trailing end. 13. An element for a ground reinforcement method according to claim 12, further comprising at least one substantially phase helical wing adjacent the trailing end of the shaft. 14. The apparatus of claim 13 wherein at least one actual top helical wing adjacent the leading end of the shaft has a pitch that is greater than the pitch of at least one actual top helical wing adjacent the trailing end of the shaft Elements for ground reinforcement method. 15. An element for a ground reinforcement method according to any one of claims 12 to 14, characterized in that the element comprises a plate substantially fixed to the shaft at its trailing end. 16. A component for a ground reinforcement method according to any one of claims 13 to 15, characterized in that said shaft is hollow. 17. The element according to claim 16, wherein the leading end of the shaft is provided with a tip to prevent soil from clogging the co-axis. 18. The element of claim 17, wherein the tip is removable. 19. A component for a ground reinforcement method according to claim 17 or 18, characterized in that the tip is porous. 20. A component for a ground reinforcement method according to any one of claims 16 to 19, characterized in that the shaft is perforated. 16. A component for a ground reinforcement method according to any one of claims 12 to 15, characterized in that the shaft is composed of a high tensile strength pultruded plastics material. 16. The element according to any one of claims 12 to 15, wherein the shaft is made of reinforced concrete. Characterized in that an element such as that described in claim 18 is used. A method of constructing a well, characterized in that an element such as that described in claim 19 or 20 is used. Characterized in that at least one activator is injected into said ground through said co-axes of elements such as those described in any one of claims 18 to 20. Characterized by using the elements recited in any one of claims 18 to 20 above. A ground reinforcement method characterized by being substantially described with reference to any one of the third, fourth, sixth, seventh, ninth, tenth, eleventh or twelfth aspect of the attached drawings. An anchor element substantially as described with reference to any one of the second, fifth, eighth, thirteenth or fourteenth aspect of the attached drawings. A method of reducing water in a ground substantially as described with reference to FIG. 7 of the accompanying drawings. Characterized in that it is substantially described with reference to FIG. 13 of the accompanying drawings. 14. A method as claimed in any of the preceding claims,