US3754401A

US3754401A - Earth anchor

Info

Publication number: US3754401A
Application number: US00213434A
Authority: US
Inventors: J Lipow
Original assignee: Individual
Current assignee: Individual
Priority date: 1971-12-29
Filing date: 1971-12-29
Publication date: 1973-08-28
Anticipated expiration: 1990-08-28

Abstract

This invention relates to the anchoring of a tension member into the earth. Two packing members are positioned in a hole in the earth about a quantity of packing material. The packing members are then forced toward one another which compresses the packing material and forces it into the surrounding earth. The earth surrounding the packing material is also compressed and thereby strengthened. The packing members are then locked in this compressed mode about a structural tension member. The strengthened earth and the anchoring unit then act together to anchor the structural tension member securely in the earth.

Description

United States Patent [191 Lipow EARTH ANCHOR [76] Inventor: Joseph H. Lipow, 51 14 Venice Blvd.,

Inglewood, Calif.

22 Filed: Dec.29, 1971 211 Appl. No.: 213,434

[52] US. Cl. 61/39, 61/45 B [51] Int. Cl E0241 5/74 [58] Field of Search 61/45 B, 39, 36;

[56] References Cited UNITED STATES PATENTS 2,950,602 8/1960 Lang 61/45 B 3,304,828 2/1967 Karhu 85/75 X 3,371,494 3/1968 Lagerstrom 61/45 B X 1,560,095 11/1925 Peirce 85/74 1,628,253 5/1927 Lyddane 85/67 2,028,881 1/1936 Saleh 85/74 X 2,075,714 3/1937 Hamill 85/67 Aug. 28, 1973 Primary ExaminerDennis L. Taylor Attorney-Charles G. Lyon et a].

[57] ABSTRACT This invention relates to the anchoring of a tension member into the earth. Two packing members are positioned in a hole in the earth about a quantity of packing material. The packing members are then forced toward one another which compresses the packing material and forces it into the surrounding earth. The earth surrounding the packing material is also compressed and thereby strengthened. The packing members are then locked in this compressed mode about a structural tension member. The strengthened earth and the anchoring unit then act together to anchor the structural tension member securely in the earth.

14 Claims, 16 Drawing Figures Patented Aug. 28, 1973 6 Sheets-Sheet 1 NW W m4 H m 5 w J A77'OZA/6V5 Patented Aug. 28, 1973 6 Sheets-Sheet 2 INVENTOR J056P/7 H L/POW A TTOE/VEVS Patented Aug. 28, 1973 3,754,401

6 Sheets-Sheet 5 F/N/5H 66%! 06 WWW? INVENTOR JOSGPH H, /POW ATTOEA/6V5 Patented Aug. 28, 1973 6 Sheets-Sheet 6 .25 Bra 1% INVENTOR JOSPH H c/POW ATTdF/VEMS EARTH ANCHOR BACKGROUND OF THE INVENTION Earth anchors for securing structural tension members are presently employed as tie-backs to support retaining walls, shoring and the like to prevent their collapse into an excavation or onto a lower area. These earth anchors have been of two basic types: the friction type which relies upon the friction created between the sides of the drilled hole and the concrete poured therein and the underreamed type wherein the diameter of the bottom of the hole is enlarged by underreaming before the concrete is introduced to form a concrete ball that cannot be pulled through the drilled hole. Both types of anchors have shown themselves to be of practical importance in the construction industry, but they characteristically exhibit certain disadvantages. The friction type anchors are formed by drilling the hole, placing the steel tension member therein perhaps having a flange at its lower end, pumping the concrete into the cavity, and allowing it to set. The underreamed type requires the costly additional, intermediate step of underreaming the hole. The anchoring force for the friction type is provided along the length of the resulting concrete column while the underreamed type relies on the interference created by the concrete ball. Another friction type anchor employs a structural tension member and a flanged anchor piece on which earth is piled to fill the hole to provide a column of earth in place of the concrete. A frictional type anchor does not compact or press into the surrounding soil, and therefore, the strength or stability of the surrounding earth is not enhanced.

Several disadvantages are inherent in the frictional earth anchor design. Because the anchor does not otherwise hold onto or physically interlock with the surrounding earth, an exceptionally long anchor ,is required. In shoring an excavation, an assumed failure plane is determined. This plane intersects the plane of the retaining wall at the floor of the completed excavation and rises to the surface at some angle with the plane of the retaining wall. The angle of the assumed failure plane depends upon the nature of the surrounding earth. The earth anchors must provide the total required anchoring force behind the assumed failure plane. The portion of earth between the assumed failure plane and the plane of the retaining wall would not provide anchoring support in the event that this material structurally failed. Consequently, the friction type earth anchor must extend into the earthwell beyond the assumed failure plane in order that sufiicient surface contact is provided between the concrete and the in situ soil.

A disadvantage with both types of earth anchors is that they are permanently positioned in the earth. The expense incurred in removing the concrete block is prohibitive. ln metropolitan areas it is generally desired that the excavation extend to the edge of the property. In such situations the earth anchors must extend into the adjoining property or under roadways. The adjoining property owner or local government is far more reluctant to agree to the intrusion if the anchoring members are permanently fixed in position.

The use of concrete creates further disadvantage during construction of the anchor. Time is required for the concrete to set. The set time greatly increases the time required for fabrication. Furthermore, the problems associated with the use of concrete in freezing temperatures may be encountered during some parts of the year. Also, the anchor cannot be tested to determine if it has sufficient holding strength until the concrete has set, which is a common problem with friction type anchors. By the time the concrete is set, the building fabrication or shoring is delayed unreasonably if the anchor must be replaced.

Thus, either type of earth anchor can provide sufficient force to adequately support a retaining wall or other similar structure. However, with either system, the inherent problems associated with the handling of concrete, the placement of a permanent anchoring structure and the required overall size of the anchors detract from the practical employment of the system.

SUMMARY OF THE INVENTION The present invention provides an improved anchor which operates to compact the in situ earth surrounding the anchor and forces compacting material into an integral relationship with the surrounding earth. To form the anchor, a structural tension member is placed in a hole drilled into the earth. A packing element is located at the lower end of the structural tension member. Packing material such as gravel is then fed into the cavity and comes to rest adjacent the positioned packing element. The quantity of packing material placed in the hole is only required to fill a small portion of the cavity. A second packing element is then driven down the structural tension member and is forced toward the first packing element which thereby causes the packing material to compress and move radially to compress the surrounding earth. The elements are then locked in this high compression mode. The resulting anchor creates extensive lateral forces and tends to cause the packing material to act as an integral unit with the in situ earth. As a result, the highly compacted system exhibits a high resistance to shear strain which in turn holds the packing elements and the structural tension member fixed relative to the surrounding earth.

This improved earth anchor solves a number of problems associated with the friction type earth anchor. Because of the resulting lateral forces the anchoring unit exerts on the surrounding earth, the holding strength of the anchor is much higher per unit of length than the friction type anchor which did not create lateral forces into the surrounding earth. As a result, the packing type anchor requires less penetration beyond the assumed failure plane than the friction type anchor. In less stable soils, the compaction type anchor also helps to compact and stabilize the surrounding earth. Because a greater volume of material is stabilized, the operating section of the anchor may be placed much closer to the assumed failure plane. This further reduces the amount of penetration required beyond the assumed failure plane.

This invention does not employ the use of concrete or other material requiring a period of time to set up. This greatly reduces the length of time required to install'the anchor and allowsfor immediate testing and inspection of the final result. Furthermore, the avoidance of concrete in the system eliminates the problems associated with pouring concrete in temperatures below freezing. Also, the presence of water in the hole will not create problems with the packing material which may occur with the use of concrete.

The resulting compaction anchor is also partially removable when it is no longer needed. The structural tension member may be unlockedand removed. This feature is of great advantage where the anchoring device must extend into adjoining properties.

Because all of the anchoring forces are located at the lower end of the tensioning member, ajacket or sleeve may be placed in the hole down to the upper packing element. The employment of such a sleeve is very useful where the in situ earth is unstable and tends to fall into the hole while the anchor is being fabricated. With the friction type anchor, such a sleeve could not be employed. In the friction type anchor, the retaining forces were dependent upon the high frictional quality of the intersection of the concrete with the surrounding earth. A metal sleeve could not supply a sufficient frictional intersection. Removing the sleeve as the concrete is poured would also prove exceedingly difficult and unsatisfactory.

In summary, the present invention employs a compaction unit at the end of a structural tension member. The operative portion of the unit acts over a small portion of the total length of the structural tension member, does not require concrete, and can be later removed. The resulting anchor requires less time to fabricate, it takes up less space and will work in a greater variety of soils than the present friction type earth anchor.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an elevation showing a portion of a drill rig having a drill which is positioned in a hole suitable for receiving an earth anchor.

FIG. 2 is an elevation of the hole of FIG. 1 showing the introduction of packing material with a portion of the anchor in place.

FIG. 3 is an elevation of the hole of FIG. 1 showing the earth anchor and the equipment used to compress the anchor.

FIG. 4 is a sectional top view of an earth anchor shown in position and with the compression device located above the anchor.

FIG. 5 is a cross sectional view taken along line 55 of FIG. 4.

FIG. 6 is a cross-sectional view taken along line 6-6 of FIG. 4.

FIG. 7 is an elevation showing earth anchors in various modes with the earth broken away for clarity.

FIG. 8 is a schematic side view of an earth anchor showing the extent of the compacted soil.

FIG. 9 is a perspective view of an alternate means for handling the packing material.

FIG. 10 is a perspective showing another alternate means for handling the packing material.

FIG. 11 is a sectional elevation illustrating an alternate use for the invention.

FIG. 12 is a sectional elevation showing a second alternate use for the invention.

FIG. 13 is a schematic plan view illustrating a use for the invention where the structural tension members extend above ground.

FIG. 14 is a sectional elevation showing additional packing elements for use with relatively fluid earth.

FIG. 15 is a cross-sectional view taken along line l5l5 of FIG. 14.

FIG. 16 is a cross-sectional view taken along line l515 of FIG. 14.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to the drawings, the drill rig 10 illustrated in FIG. 1 is used first to drill the hole 12 into the earth where desired. The anchoring unit may be any diameter, the proper diameter of the hole 12 being determined by the size of the anchoring apparatus which must fit therein. The hole size is further limited by the stability of the soil. Eight to 12 inch diameter holes appear to be best suited for normal construction projects. It is believed that the diameters of the holes 12 may be as small as 4" or as large as 16" where soil conditions so dictate. The depth of the hole 12 is determined by the stability of the surrounding soil, its ability to increase in shear strength under compression and the angle of the assumed failure plane. Naturally as the stability of the soil decreases, the longer the required shaft. The assumed failure plane also will vary with the stability of the soil. To meet the requirements imposed using the least amount of drilling, the hole 12 must be perpendicular to the assumed failure plane. Thus, the hole 12 will be at an angle downward from the horizontal which is equal to the angle between the assumed failure plane and the vertical. This relationship is best seen in FIG. 7. It should be remembered that it is not mandatory that the hole 12 run perpendicular to the assumed failure plane, but such a configuration will require the shortest hole. The anchoring unit must be positioned behind the assumed failure plane to insure that the anchor will not slip with the surrounding soil. It is advantageous to place the anchoring unit a short distance behind the assumed failure plane in order that the compressive stresses developed in the surrounding soil will not be relieved by a failure of structural integrity along the assumed failure plane. In achieving the proper depth in certain soils, difficulty is experienced in drilling small diameter holes with a short auger because it must be pulled from the hole a great many times to unload the drilled soil. Therefore, for ease of operation, a continuous flite machine is suggested for use with the drill rig 10. If there is a chance that a significant cave-in may occur in the hole 12, a casing may be positioned therein. It is suggested that the casing not extend into the area to be used for the anchor, but it may remain in the hole 12 until the structural tension member 16 is removed.

As shown in FIG. 2, the lower packing element 14 is positioned with the structural tension member 16 in the hole 12. The body of the lower packing element 14 is made up of four identical sections 18 which together form a conical body. A cable 20 is wrapped about the nose of the body sections 18 to hold them together on the structural tension member 16. The body of the lower packing element 14 is conical in order that the surface of each body section 18 will exert a component of force which is perpendicular to the structural tension member 16 when the overall anchor unit is compressed. The body of the lower packing element 14 is split into sections 18 in order that the sections may pivot about the cable 20 into the in situ soil to prevent a flow of soil and packing material out of the anchoring unit. A small conical taper 22 is made in the nose of the conical body of the lower packing element 14 to prevent stretching of the cable 20 when the segments 18 are pivoted into the in situ soil. The center of the body of the packing element 14 is hollow and provides a conical bearing surface 24. The conical bearing surface 24 provides a surface from which the several segments 18 can be forced into the in situ soil. Cone angles of 19 have been found to give the best results for the conical surface 24. Shields 26 are attached to each section 18 by set screw 28. The shields 26 cover the gaps created between the sections 18 when the sections 18 have been forced, into the surrounding soil. The shields 26 are optional with the more stable soils and larger grained packing materials. The shields 26 are attached on only one side in order that segment 18 may expand radially. Relatively light gage sheet in the order of 0.065 to 0.125 steel plate is satisfactory as a certain amount of distortion is not detrimental to the operation of the unit. The conical body of the upper packing element is identical to the conical body of the lower packing element just described, and the various parts of the upper unit have been identified with corresponding numbers, designated by the lower case u for upper.

The lower packing element 14 is held on the rod by a truncated cone 30 which is in turn held on the structural tension member 16 by a hex nut 31 threaded into the tension member 16. The truncated cone 30 is sized to fit into the conical bearing surface 24 of the lower packing element 14. When the lower packing element 14 is held in position and the structural tension member 16 is pulled through the front of the lower packing element 14, the truncated cone 30 acts in conjunction. with the conical bearing surface 24 to'spread the sections 18 radially into the in situ soil.

' Returning to FIG. 2, the lower packing element 14 is positioned in the bottom of the hole 12 with the structural tension member 16, the truncated cone 30 and the retaining hex nut 32 in place. The body sections 18 have not been pivoted into the surrounding soil at this point of the operation. The loading unit 34 is then brought into position, and a tube 36 is positioned in the hole 12. The loading unit 34 is then caused to introduce packing material 38 through tube 36 into the lower portion of the hole 12 immediately adjacent the lower packing element 14. The introduction of the packing material 38 may be facilitated by charging the'packing material 38 pneumatically or with a carrier. It has been determined that for most applications gravel provides the most suitable and economical packingmaterial. It is virtually impossible to compress a confined gravel mass in volume by simple, static compression. Consequently, the gravel will expand radially against the surrounding soil. The pivotal action of the segments 18 as the unit is compressed helps to disturb the gravel packing material 38 in order that it may be moved radially into the surrounding earth by a longitudinal compressive force. When the surrounding soil is weak, plastic deformation will develop in a peripheral layer around the hole 12. In this case, it is believed that the gravel packing material 28 will be pushed well into the soil strength of the surrounding soil to a considerable distance from the original hole diameter. In effect, a large integral anchoring plug is formed which is significantly larger than the original anchoring unit. FIG. 8 illustrates the compressive stresses developed in the surrounding soil. Naturally the degree of compressive stress with relation to the distance from the center of the anchoring unit is a continuous function, and the effect of the compression extends even beyond the boundary illustrated in FIG. 8. Two alternate configurations for the packing material are illustrated in FIGS. 9 and 10. FIG. 9 illustrates a screen canister 40 containing the gravel packing material 38. The cylindrical wall 42 of the canister 40 is made of light screen or other similar material sufficient to hold the gravel in position while it is being positioned in the hole. Under compression the screen must be capable of either bursting or stretching to completely pack the cavity. A tube 44 is positioned through the canister 40 to keep the packing material 38 from interferring with the structural tension member 16. Caps 46 are positioned at each end of the canister 40. It is preferable that the caps 46 be capable of crushing or rupturing under low pressures in order that the packing elements 14 and 1414 can work effectively. Guide strips 48 are located about the canister 40 to aid in centering the anchoring unit in the hole 12. The packing material illustrated in FIG. 10 is another possible configuration that will facilitate handling. The packingmaterial is formed into two semi-cylindrical pieces 50 having provision for the structural tension member 16 in channels 52. The matrix constraining the gravel packing material may create a light bond which is easily fractured under compression. Such a lightly bonded material would then act much like the unbonded gravel packing material 38. Under certain conditions, the matrix holding the packing material may provide the bonding strength of concrete. In this case, the two semi-cylindrical pieces 50 will retain their original integrity and act as two wedging units. Even with the packing material 38 comprising two or more concrete blocks, the packing elements 14 will act to force the parts 50 into the surrounding soil thereby enhancing its ultimate shear capabilities.

Turning to FIG. 3, the charging apparatus 36 is removed from the hole 12, and the upper packing element l4u is positioned on the structural tension member 16. The upper packing element l4u must have sufficient clearance on the structural tension member 16 so that it will not bind on the shaft. The upper packing element l4u is most conveniently positioned on the bottom of the hole 12 by pushing on the conical bearing surface 24u. If the element 1414 was to bind on the shaft 16, the pushing element employed to position the upper element 1414 may cause the segments 18a to rotate into the surrounding earth. Following the placement of the upper packing element 1414, a truncated conical wedge 54 is positioned on the structural tension member 16. The smallest diameter of the conical wedge must fit into the closed upper packing element l4u on the conical bearing surface 2414. A conical concentric inner surface 56 is provided on the truncated conical wedge 54. Locking wedges 58 are positioned between the inner surface 56 of the conical wedge 54 and the structural tension member 16. Three or more locking wedges 58 are normally used to form a locking system. The wedges 58 when positioned on the structural tension member 16 do not quite meet in order that they may be pressed into the tension member 16 by the truncated conical wedge 54. A gripping surface 60 is provided on the locking wedges 58. A cylindrical mandril 62 having a wedge setting ram 64 is then positioned on the structural tension member behind the truncated conical wedge 54 and the locking wedges 58. The wedge setting ram 64 is threaded onto the mandril at 66. The ram 64 has a centered hole 68 through which the structural tension member 16 will freely slide. The diameter of the ram 64 is reduced near the thrusting surface 70 in order that the ram 64 may fit into the hollow provided in the upper compaction element 1414. An increased inner diameter is provided at 72 to allow the locking wedges to remain in a noninterference position with respect to the truncated conical wedge 54. A resilient wedge clamp 74 is positioned about the locking wedges 58 to hold them in place during assembly. The clamp 74 may consist of a strong rubber band. 4

When the upper packing element 1414, the truncated conical wedge 54 and the locking wedges 58 are positioned adjacent the packing material 38, an hydraulic center hole ram 76 is positioned on the upper end of the mandril 62, and tension is imposed on the structural member 16. The two packing elements 14 and 1411 are thereby compressed toward one another. As the reaction to the compressive forces increases, the

wedges

30 and 54 enter the conical bearing surfaces and cause the segments 18 and 18a to pivot into the surrounding soil. The maximum compressive force possible will depend on the elastic limit of the structural tension member. The tension load on the tension member 16 between the packing elements 14 and 14a must not exceed the yield strength of the member 16 minus the maximum tension load expected on the upper end of the member 16. To achieve the same result, the tension member 16 may be pulled while the mandril 62 is held fixed relative to the ground. Similarly, the tension member 16 could be held fixed and the mandril 62 operated. Also, the loading could be alternated between the tension member 16 and the mandril 62. When the maximum compression possible has been reached, hydraulic pressure is applied through tube 78. The resulting increase in pressure in the circular cavity 80 causes the piston 82 to force the locking wedges 58 into locking position with the truncated conical wedge 54. Seals 84 are provided to increase the efficiency of the hydraulic cavity 80. The hydraulic pressure in the tube 78 is then re lieved, and the hydraulic center hole ram is removed. The mandril is then withdrawn from the hole 12; and if a casing were used, it is likewise withdrawn unless the structural tension member 16 is to be removed later. The structural tension member is then attached to the retaining wall and preloaded if required. The shaft may be back filled if removal of the structural tension member 16 is not required. With the first series of anchors located and fixed in position, further excavation may proceed to the next level where anchoring members are required. The identical process is then repeated. Because the assumed failure plane is approaching the plane of the retaining wall, the succeeding levels will require shorter holes 12 and structural tension members 16. This is best illustrated in FIG. 7.

To remove the structural tension member 16 from the hole 12, sufficient pressure is again placed on wedge 54 by a ram 64 to relieve all tension in the structural tension member 16 between packing elements l4 and 1414. This will unlock the locking wedges 58 and relieve wedge 30. The structural tension member 16 can then be rotated to remove hex nut 32 and withdrawn. Because hex nut 32 may not have become fixed in the in situ soil, the nut 32 may be constrained not to rotate with the structural tension member 16 by tying it to a segment 18 by a locking wire.

When the in situ soil is of an extremely unstable nature, where it is anticipated that flow may occur about the packing elements 14 as the earth anchor is compressed, precast concrete cones 98 illustrated in FIGS. 14-16 should be employed. The cones 98 are made up of segments 100 held together by retaining cables 102. The concrete cones 98 should fit on the packing elements 14 so that the retaining cables 102 are forward of the retaining cables 20 in order that they are not placed in tension and thereby resist the movement of the packing element sections 18 and l8u when the anchoring unit is put in compression.

Other uses for the present invention are illustrated in FIGS. ll, 12 and 13. In FIG. 11, a post 84 is both held in tension by the stressed tension member 16 and supported by the concrete 86. In FIG. 12, a prefabricated retaining wall can be supported during the time required for the concrete to set. A trench is dug along the plane of the retaining wall. This would be accomplished with the use of heavy equipment to avoid the possibility of cave-ins on workers. Premanufactured wall panels 88 are then positioned in the trench and capped with a beam 90. An earth anchor according to the present invention is then positioned in the earth according to the assumed failure plane associated with the proposed finished grade. The excavation is then carried out and concrete 92 is formed up and poured. Later the earth anchor may be removed when the concrete 92 has suf- I ficient strength. FIG. 13 illustrates the use of the present invention where the structural tension members 16 extend above ground. In the present example a bridge 94 is supported against side loading from the flow of a river 96.

The present embodiments of this invention are to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description and all changes which come within the meaning and range of equivalency of the claims therefor are intended to be embraced therein.

I claim:

1. Apparatus for anchoring a support member in the ground, comprising: a tension member, opposed packing elements, means for rigidly locating said opposed packing elements relative to said tension member, packing material, and means for compressing said opposed packing members into said packing material including a mandril located about said tension member capable of exerting pressure on one of said opposed packing elements and a tensioning device capable of pulling on said tension member concurrently with the operation of said mandril.

2. The apparatus of claim 1, wherein said packing el ements and said packing material act together to compress the in situ soil about the apparatus.

3. The apparatus of claim 1, wherein said opposed packing elements are segmented truncated conical wedges each comprising a-plurality of segments and means for expanding said plurality of said segments in a radial direction.

4. The apparatus of claim 3, wherein said expanding means comprises an inner conical surface on said segmented truncated conical wedge and a forcing wedge which operates on said inner conical surface, said forcing wedge being positioned within said inner conical surface.

5. Apparatus for anchoring a support member in the ground, comprising, a tension member, opposed packing elements, packing material between said opposed packing elements, and means for rigidly locating said opposed packing elements relative to said tension member including a block attached to said tension member behind one of said opposed packing elements and a plurality of locking wedges locking on said tension member behind the other of said opposed packing elements.

6. The apparatus of claim 1, wherein said packing material is gravel.

7. The apparatus of claim 1, wherein said apparatus further comprises a segmented truncated conical collar positioned about said opposed packing elements.

8. The apparatus of claim 1, wherein said packing material is initially held within a container which is sufficiently weak to structurally fail under employment of said packing elements.

9. The apparatus of claim 1, wherein said tension member is removable.

10. Apparatus for anchoring a support member in a ,bore hole in soil of various characteristics, comprising;

an elongated tension member, a pair of opposed packing elements mounted on said member in substantially spaced relationship, packing material between said elements capable of irregular deformation and flow,

means for axially advancing said packing elements toward each other on said tension member for causing said packing material to expand radially compressing the soil, said packing elements including means for expanding radially in response to said axial advancement for inhibiting the flow of said packing material passed said packing elements, and locking means for rigidly locating said packing elements relative to said tension member.

11. The apparatus of claim 10 wherein said means for advancing said packing elements comprise a mandril for applying axial compressive force to one packing element and the tension member for applying axial tension force to the other packing element in the opposite direction.

12. The apparatus of claim 10 wherein said packing material comprises a relatively incompressible granular material.

13. The apparatus of claim 10 wherein said locking means includes selectively operable means associated with one of said packing elements and being adapted to selectively rigidly locate or dislocate that said packing element relative to said tension member as required.

14. The apparatus of claim 10 wherein said packing elements each include segmented truncated conical wedges with their small ends facing each other, wedge means for expanding the larger ends of each segmented truncated conical wedge, and means positioned on said segmented truncated conical wedges extending across at least a portion of the space formed between the expanding segments of said segmented truncated conical wedge.

Claims

2. The apparatus of claim 1, wherein said packing elements and said packing material act together to compress the in situ soil about the apparatus.

3. The apparatus of claim 1, wherein said opposed packing elements are segmented truncated conical wedges each comprising a plurality of segments and means for expanding said plurality of said segments in a radial direction.

6. The apparatus of claim 1, wherein said packing material is gravel.

9. The apparatus of claim 1, wherein said tension member is removable.

10. Apparatus for anchoring a support member in a bore hole in soil of various characteristics, comprising; an elongated tension member, a pair of opposed packing elements mounted on said member in substantially spaced relationship, packing material between said elements capable of irregular deformation and flow, means for axially advancing said packing elements toward each other on said tension member for causing said packing material to expand radially compressing the soil, said packing elements including means for expanding radially in response to said axial advancement for inhibiting the flow of said packing material passed said packing elements, and locking means for rigidly locating said packing elements relative to said tension member.