US3630036A

US3630036A - Elongated element to be driven into the ground together with a shoe

Info

Publication number: US3630036A
Application number: US886700A
Authority: US
Inventors: Abraham Francois Van Weele
Original assignee: Tot Aanneming Van Werken Voorheen HJ Nederhorst NV
Current assignee: Tot Aanneming Van Werken Voorheen HJ Nederhorst NV
Priority date: 1968-12-20
Filing date: 1969-12-19
Publication date: 1971-12-28
Anticipated expiration: 1988-12-28
Also published as: ES374713A1; DE1963720C3; BE742510A; GB1242959A; FR2026742A1; DE1963720A1; MY7300403A; DE1963720B2

Abstract

An elongated element, such as a foundation pile or a tube for casting a concrete foundation pile in situ, adapted to be driven in the ground, in particular by vibration, together with a shoe, and comprising at least one supply pipe connected with the outer wall of the element, extending in the longitudinal direction of the same, terminating near the lower end of the element, and connectable at its top, through a supply valve, to a source of a pressure medium, in particular water under pressure. Each supply pipe, respectively, is provided at its lower end with means preventing a penetration of earth into the supply pipe substantially completely when the supply valve is closed, but allowing a discharge of the pressure medium from the supply pipe when the supply valve is open.

Description

United States Patent 2.555.359 6/1951 Montague. 2,600,150 6/1952 Abendroth 2,662,603 12/1953 Jones. 175/314 3,166,132 1/1965 Lenahan etal. 175/314 X Primary Examiner- David J. Williamowski Assistant ExaminerDavid H. Corbin [21 Appl. No. [22] Filed Dec. 19, 1969 [45] Patented Dec. 28, 1971 [73] Assignee N.V. tot Aanneming van Wei-ken voorheen i rzg zi gzs Attorney-"Waters, Roditi, Schwartz & Nissen [32] Priorities Dec. 20, 1968 [3 3] Netherlands [31] 6818364;

July 15, 1969, Netherlands, No. 6910827 ABSTRACT: An elongated element. such as a foundation pile 5 ELONGATED ELEMENT o BE DRIVEN 01 a tube for casting a 001161516 foundation in situ, THE GROUND TOGETHER WITH A SHOE adapted to be driven in the ground, in particular by vibration, 3 Claims 3 Drawing Figs together with a shoe. and comprising at least one supply pipe connected with the outer wall ofthe element. extending in the CL longitudinal direction of the same. terminating near the lower end of the element, and connectable at its top, through a supply valve, to a source of a pressure medium, in particular water under pressure. Each supply pipe, respectively, is provided at its lower end with means preventing a penetration of earth into the supply pipe substantially completely when the supply valve is closed, but allowing a discharge of the pressure medium from the supply pipe when the supply valve is open.

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ELONGATED ELEMENT TO BE DRIVEN INTO THE GROUND TOGETHER WITH A SHOE BACKGROUND OF THE INVENTION When an elongated element provided with a shoe, such as a foundation pile or a tube for casting a concrete foundation pile in situ, is driven into the ground, for instance by vibration, the desired depth can often only be reached if a sufficient hydraulic overpressure is present or may be artificially generated.

For the latter purpose, it is known to provide an element of the above-mentioned kind with at least one supply pipe, connected with the outer wall of the element and extending in the longitudinal direction of the same. This supply pipe terminates near the bottom of the element, and is connectable at its top through a supply valve to a source of a pressure medium, in particular water under pressure.

This pressure medium serves to achieve an artificial reduction of the contact pressure of the ground particles underneath the shoe. Furthermore, if the pressure medium is a liquid, such as water, the liquid ascending around the element will carry away the ground particles, whereby space is obtained for the volume occupied by the element. However, since the pressure medium flows away in this case, it must be supplied in large quantities in order to increase the pressure in the ground pores and to reduce the contact pressure of the ground particles to such an extent that the element may be driven further into the ground. In addition, the use of a liquid pressure medium involves a considerable spoilage of the building site by the liquid discharged along the element, and in particular by the deposition of the ground particles carried along with this liquid.

Moreover, with the known elements, it is not possible to interrupt the supply of the pressure medium periodically during the driving process, because the earth would penetrate into the supply pipes during such interruptions, whereby the pipes would be clogged and a further supply of the pressure medium would be rendered impossible. On the other hand, the ground structure is frequently of such a nature that it is not only unnecessary, but even harmful to supply the pressure medium during the entire driving period, because in soft ground layers, and especially in clay and sludge layers, the supply of a liquid pressure medium has the disadvantage that too much ground is carried away, and the ground surrounding the element is heavily disturbed, so that the element is no longer entirely enclosed by the ground.

SUMMARY OF THE INVENTION The invention has the object to provide an element of the above-mentioned kind whereby the said disadvantages are effectively removed.

According to the invention, each supply pipe, respectively, is provided at its lower end with means preventing a penetration of ground into the supply pipe substantially completely when the supply valve is closed, but allowing a discharge of the pressure medium from the supply pipe when the supply valve is open.

The invention also comprises a method of driving said element into the ground, in particular by vibration.

According to this method, the supply valve is periodically closed during the driving process.

In a preferred embodiment of the method according to the invention, the supply valve is closed at least during the initial period. Since no pressure medium is supplied during the initial period of the driving process, the element is tightly enclosed by the ground, and the diameter of the region in which the ground displaced by the element is incorporated by densification is considerably increased. A leakage of the pressure medium supplied during the remaining portion of the driving process is effectively prevented in this manner, so that the quantity of the pressure medium introduced into the ground is accurately defined, and the required reduction of the contact pressure of the ground particles may be obtained with a minimum consumption of the pressure medium. If the pressure medium is a liquid, the spoilage of the building site is also effectively reduced.

BRIEF DESCRIPTION OF THE DRAWING dicated.

FIG. 3 is a longitudinal section of the lower end of a modification of the supply pipe.

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a portion of a tube 1 which is adapted to be driven into the ground, in particular by vibration, together with a loose shoe 2. The tube 1 serves as a mould for the casting in situ of a concrete foundation pile, and is afterwards removed.

The tube 1 is provided on its outside with a plurality of supply pipes 3 for a pressure medium, in general water under pressure; these supply pipes are spaced at equal distances along the periphery of tube 1. Three supply pipes are shown in the drawings. The supply pipes 3 are attached, for instance by welding, to the outer wall of tube 1. As appears from FIG. I, the lower ends of the supply pipes 3 may be offset to the outside, at their top, the supply pipes 3 are connected, through a supply valve, to a source ofthe pressure medium.

At its lower end, each of the supply pipes 3 carries an outlet nozzle 4, screwed into a nipple 5; the nipple 5 is screwed into the lower end of the supply pipe. The outlet nozzle 4 has an outlet channel 6 with a reduced diameter, whose lower part 7 terminates immediately underneath the loose shoe 2, and is downwardly inclined toward the axis of tube 1.

A back pressure valve 8 is arranged above the outlet nozzle 4. The valve 8 comprises a spring 9 supported by the outlet nozzle 4, and exerting an upward force, through the intermediary of a pressure member 10, on a spherical valve body 11, whereby the latter is pressed against a valve seat 12 provided in the top face of the nipple 5.

When the supply valve at the top of the supply pipe 3 is open, the valve body 11 is lowered by the overpressure of the medium, which may amount to 10 atm., so that the pressure medium is discharged through the outlet nozzle 4. As soon as the supply of the pressure medium is interrupted, the back pressure valve 8 is immediately closed, so that a penetration of earth into the supply pipe is substantially completely prevented.

As appears from FIG. 2, the peripheral edge of the loose shoe 2 is provided with recesses 13 partially enclosing the outlet nozzles 4.

FIG. 3 shows a modification of the supply pipe 3. A sleeve 14, made of a porous material, such as sintered bronze, rests against a shoulder 15 formed in the supply pipe 3, and is retained by a plug 16 screwed into the lower end of the supply pipe. The interior of the sleeve 14 is in open communication with the interior of the supply pipe 3. Outside the sleeve 14, an outlet channel 17 has been formed in the wall of the supply pipe 3. The channel 17 terminates immediately underneath the loose shoe 2, and is downwardly inclined toward the axis of the tube 1.

The porous sleeve 14 passes the pressure medium, but prevents the ground from penetrating into the supply pipe. This embodiment is possible because the force of the discharged jet of the pressure medium does not play any significant part.

The invention makes it possible to interrupt the supply of the pressure medium periodically during the driving process without any danger of a clogging of the supply pipes by the surrounding earth.

Preferably, the supply of the pressure medium is interrupted during the initial stage of the driving process, so that the tube 1 may be tightly enclosed by the ground, and any leakage of the pressure medium during the remaining portion of the driving process is effectively prevented. Thus, the required reduction of the contact pressure of the ground particles is obtained with a minimum consumption of the pressure medium, and a spoilage of the building site with overflowing water is prevented.

Furthermore, the supply of the pressure medium may be stopped immediately before the required depth is reached, so that a sufficient densification of the ground underneath the shoe 2 may be obtained, which is necessary for adequate carrying of the final foundation pile.

The invention is not restricted to the embodiments shown in the drawings, which may be modified in various ways within the scope of the invention. For instance, the invention may also be applied to a prefabricated foundation pile.

What is claimed is:

1. In combination, an elongated foundation pile element having a shoe at the lower end thereof, for casting a concrete foundation pile in situ and adapted to be driven into the ground by vibration; and at least one supply pipe connected to the exterior of said element and being coextensive therewith along its longitudinal length, said supply pipe terminating adjacent the lower end of said element, said supply pipe being connected at its upper end to a source of liquid pressure medium adapted to supply said pressure medium to said supply pipe in an intermittent manner during the driving of said element, a pressure medium outlet nozzle in said supply pipe at the lower end thereof, said nozzle comprising an axial channel and a liquid outlet channel extending obliquely from said axial channel and being directed toward the longitudinal axis of said element and having an outlet orifice terminating immediately adjacent and below said shoe, and means in said supply pipe in the lower region thereof for permitting a discharge of said pressure medium from said supply pipe through said nozzle during periods of supply of liquid pressure medium to said pipe, and preventing penetration of ground particles into said supply pipe upon cessation of liquid pressure medium flow through said pipe.

2. The combination as claimed in claim 1, wherein said lastmentioned means comprises a ball check valve, vale seat means in said supply pipe, and resilient spring means biassing said valve toward said valve seat means into normally valveclosed position, said valve being adapted to open in response to liquid pressure medium flow through said supply pipe, and close upon cessation of pressure medium flow so as to prevent ground particles entering said supply pipe.

3. The combination as claimed in claim 1, wherein said lastmentioned means comprises a sintered bronze, porous sleeve member interposed between the interior of said supply pipe and said outlet channel, said liquid pressure medium being conveyed through said sleeve member toward said channel during periods of pressure medium flow, and preventing entry of ground particles into said supply pipe upon cessation of liquid pressure medium flow through said pipe.

Claims

2. The combination as claimed in claim 1, wherein said last-mentioned means comprises a ball check valve, vale seat means in said supply pipe, and resilient spring means biassing said valve toward said valve seat means into normally valve-closed position, said valve being adapted to open in response to liquid pressure medium flow through said supply pipe, and close upon cessation of pressure medium flow so as to prevent ground particles entering said supply pipe.

3. The combination as claimed in claim 1, wherein said last-mentioneD means comprises a sintered bronze, porous sleeve member interposed between the interior of said supply pipe and said outlet channel, said liquid pressure medium being conveyed through said sleeve member toward said channel during periods of pressure medium flow, and preventing entry of ground particles into said supply pipe upon cessation of liquid pressure medium flow through said pipe.