Anchorable Pile

Abstract

A piling consisting of a main, elongated pile member which has within its body, a plurality of retracted anchors which after the pile is inserted into the ground, are capable of being independently moved laterally of the piling member to provide anchors for the piling member without movement of the piling member.

Description

A structural piling derives its supporting value from either and/or both the bearing on its embedded end and cohesive friction of the surrounding earth on the pile surface area. In areas characterized by cohesive, low-strength soils which are excessively deep, piling economy and size is determined by utilizing piling members whose maximum supporting value is governed by the friction or shear strength of the soil media. In such cases where pile end bearing cannot be relied on, the economical pile size and hence the rated supporting value of each pile is significantly minimized to values well below that of which the pile itself is capable of sustaining. Various means of attempting to insure maximum mobilization of all available soil shear resistance are in use ranging from a "Y" cross-sectional pile area to a corrugated pile shell. A variety of means are also in use that attempt to maximize the positive pile bearing or "mechanical locking" or "keying" effect of the pile to its surrounding soil. They include, among others, the widely used step tapered shell pile, the Franki-type caisson (wherein the tip area is excavated to permit concrete placement of a larger area bulb at the pile base), etc.

The methods stated above attempt to make maximum use of or increase (1) the effective cross-sectional area of the pile which can be used in pile tip bearing, and (2) the frictional (shear) resistance between the exterior surface of the pile and the surrounding soil media. All methods used to date require special pile sections and/or construction methods and procedures.

Pilings of all sorts are commonly used to support structures, retaining walls, resist uplift and prevent earth movement. Such pilings are driven essentially vertical into the ground by pile drivers or the like. While it is the intent to have the pilings generally immobile at full penetration in the earth, the weight of the structures on the pilings, earth movement, settlement, consolidation, etc., tends to loosen the pilings permitting further penetration of the pilings with resultant distortion of the structure. The loosening may be lateral but it is in most cases almost always vertical. A number of different types of earth anchors have been proposed, but in all of the known types, the laterally expending anchor members are extended by pivoting from a point near the head of the elongated earth penetrating member. These expanding anchor members are expanded away from the elongated shaft by pulling the shaft backwardly out of the hole into which it has penetrated which reduces end bearings, or by pivoting the anchors mechanically which leaves a void above the anchors. This type of anchor is intended to anchor against pulls or tension directed out of the hole, and such anchors do not prevent inward movement of the piling shaft. In fact, inward movement of this type of anchor tends to collapse the anchor system.

Included among the objects and advantages of the invention is a piling arranged with extendable anchors which are laterally extended from the pile axis after the piling has reached its desired penetration in the earth and without movement of the piling.

Another object of the invention is to provide laterally extending anchors for piling members, which anchors may be independently extended normally to the axis of the piling by a simple mechanism which may be later withdrawn and reused.

Still another object of the invention is to provide a piling with greatly increased ability to resist not only bearing loads but in resisting uplift forces such as those created by hydrostatic forces. By providing a "locked key" near the pile tip to act against the increased "shear resistance cone" and weight of earth will minimize the necessity for mass foundations and battered piling.

These and other objects and advantages of the invention may be readily ascertained by referring to the following description and appended illustration in which:

FIG. 1 is a side elevational view of one form of the invention, in partial section, illustrating one means of extending anchor members of a piling;

FIG. 2 is a schematic cross section of a piling along line 2--2 of FIG. 1;

FIG. 3 is a schematic cross-sectional view of the piling of FIG. 1 taken along section line 3--3 with the lateral anchors in retracted position;

FIG. 4 is a schematic cross-sectional view of the piling of FIG. 1 similar to FIG. 3 along section line 3--3 with the anchors in partially extended position;

FIG. 5 is a schematic cross-sectional view of the piling of FIG. 1 taken along section line 3--3 illustrating the full extension of the anchors;

FIG. 6 is a cross-sectional detailed view of one end of an anchor according to the invention showing a modified piling configuration;

FIG. 7 is a top plan view of the modified form of piling of FIG. 6 with its anchor members in full extended position; and

FIG. 8 is a top plan view of another modified form of piling according to the invention with its anchor members fully extended.

In general, the invention includes a hollow, elongated piling member having a penetrating point which is arranged to be driven into the earth by any suitable means. A plurality of anchor members or shear plates are telescoped in the piling member at different elevations preferably, but not necessarily, near the penetrating point of the shaft. These shear plates are completely retracted while the piling is being driven into the ground. When the piling has reached its desired penetration a mechanism is inserted through the hollow core of the piling member and used to move the shear plates normal to the axis of the piling into the surrounding earth, thus providing a means of anchoring the piling against vertical deflection .

In the embodiment shown in FIG. 1, a hexagonal, hollow core pile 10 is provided with a penetrating point 12 at its lower end and open at the upper end 14. Extended inside of the pile void is a circular shaft 16 having the mechanism assembly 18 and 20 at the lower end. The assembly consists of a tapered screw thread 20 terminating in a tapered drift pin 22 at its lower end. A plurality of shear plates or anchor plates are mounted in slots in the piling shaft. As shown in FIG. 1, the shear plate 25 is extended through an aperture 25a in the shaft. Shear plate 28 extends through its aperture 28a at a different elevation from that of aperture 25a. By forming the apertures at different heights, six shear plates may be telescoped from the shaft. As shown in FIG. 4, plates 25 through 30, inclusive, are arranged through their own apertures telescoped inside the piling 10. Each plate at its inner end is provided with an arcuate cutout. The notches are indicated in FIG. 4 as 25n, 26n, etc. With all of the plates retracted, shown in FIG. 3, the notches form a central opening 35 which permits the drift pin to pass centerwise of the plates and start the plates moving outwardly under the influence of the screw 20.

In using the device of FIGS. 1 through 5, the shear plates remain completely retracted within the body of the pile 10 during the pile driving operation. When the piling has penetrated the earth to its desired depth, the circular shaft 16 and mechanism assembly 18 and 20 are inserted into the pile void and torque is applied to the shaft 16. The shaft is, in turn, forced downwardly engaging the plates one after the other from the uppermost one to the lowermost. Engagement is initially with the drift pin follower by the screw thread 20. Initially, the tapered drift pin 22 enters the opening 35 and permits the thread on the tapered screw 20 to engage the shear plates one after the other. When the screw thread 20 is moved fully to the bottom, all the plates are fully extended, shown in FIG. 5, and forces into the earth around the shaft of the piling. The extended shear plates increase the effective resistive cross-sectional area of the pile.

The plates are designed for each pile section and adapted so that in retracted position, their outer edges will be flush with the outside face of the pile. The limiting horizontal dimension to which the plates may be extended is governed by the size of the pile and the size of the central void. Generally, the larger the size of the pile and available void, the greater will be the effective area available in the extruded plates. As pointed out above, to maintain the structural integrity of the pile, the openings through the pile wall are staggered along the axis of the pile. Maximum effectiveness is achieved with the plates near the pile tip, however, they may be placed at any position along the pile's length.

As shown in Fig. 1, the plates are pushed outwardly into the surrounding soil by means of a tapered thread. This device makes use of the extremely high mechanical advantage of the tapered screw. Thus, as the tapered thread is advanced, the plates are extended through the openings in the pile and full protrusion is ensured by the guide or head 18 above the screw. While substantially any number of shear plates may be used with a single tapered thread, one single series of plates which substantially covers the periphery of the pile will in most cases be adequate. The plates, of course, are positioned and spaced along the pile axis so as to coincide with the screw pitch. The use of the screw permits the plate extension, and will also permit removal, salvage and reuse of the screw thread mechanism and the drive shaft.

The use of a hexagonal pile permits the use of six plates which will be adequate for increasing the effective cross-sectional area of the pile. Other cross-sectional configurations, however, may be useful to provide a pile capable of housing a series of extendable plates. As shown in FIG. 7, a circular pile 40 is provided with a series of extendable plates 42 each of which has an outer arcuate edge 43 approximately matching the exterior surface of the pile. These plates are staggered axially along the piling, as explained above.

In the configuration of FIG. 8, a square piling 50 is provided with a series of four shear plates 52, each of which has an outer edge 53 which is squared to mate with the outside surface of the piling 50. These shear plates are staggered along the piling.

Other means may be provided for extending the shear plates laterally from the axis of the pile. A conical wedge with out screw threads may be driven between the plates to force the plates outwardly into the soil. For large cross-sectional piles, a hydraulic unit acting like a jack may be used to force each of the plates outwardly, progressively down the pile.

Claims

We claim:

1. An anchorable pile comprising a generally hollow elongated pile member having a penetrating point at one end and being open at the opposite end; there being a plurality of openings in said pile member spaced at different positions along the axis thereof; a plurality of shear plates telescoped in said pile member with one at each said opening; removable means including a tapered member extendable along the axis of said pile member, said tapered member having a threaded portion and said shear plates interfit between the threads of said tapered member, for wedgedly moving said shear plates normally of the longitudinal axis of said pile member by rotating said tapered member, and means extending through said open end for actuating said means for moving said shear plates.

2. An anchorable pile according to claim 1 wherein said plurality of openings are each elongated in a direction transverse to the longitudinal axis of said pile member.

3. An anchorable pile according to claim 1 wherein said shear plates have an outer end surface which conforms to the configuration of the exterior surface of said pile member.

4. An anchorable pile according to claim 2 wherein said extending means includes a shaft.

5. An anchorable pile according to claim 1 wherein the exterior configuration of said pile member is a hexagon.

6. An anchorable pile according to claim 1 wherein the exterior configuration of said pile member is circular.

7. An anchorable pile according to claim 1 wherein the exterior configuration of said pile is square.

8. An anchorable pile according to claim 1 wherein sufficient of said shear plates are present to substantially provide a complete circumferential surface projection around said pile member.

9. An anchorable pile according to claim 1 wherein said tapered member is withdrawable after said shear plates are moved normally.

10. An anchorable pile comprising a generally hollow elongated pile member having a penetrating point at one end and being open at the opposite end; there being a plurality of transverse openings in said pile member spaced at different positions along the axis thereof; a plurality of generally flat shear plates telescoped in said pile member with one at each said opening; removable means telescoped in said pile member having a tapered end extendable along the axis of said pile member, said tapered end arranged to contact said shear plates and move them normal to the axis of said pile member on downward movement of said removable means, and means extending through said open end for moving said removable means downwardly for moving said shear plates and upwardly for removal of said removable means.