US3805535A

US3805535A - Method for forming a body of concrete or similar material in the soil

Info

Publication number: US3805535A
Application number: US00265487A
Authority: US
Inventors: Weele A Van
Original assignee: WEELE A VAN
Current assignee: WEELE A VAN
Priority date: 1971-06-25
Filing date: 1972-06-23
Publication date: 1974-04-23
Anticipated expiration: 1991-04-23
Also published as: GB1368895A; BE785361A; IT972155B; FR2143476B1; CA944967A; JPS531570B1; NL140592B; FR2143476A1; NL7108860A; AU4378672A; DE2230238A1

Abstract

A method of forming a body of concrete or similar material in the soil comprises the steps of making a hole in the soil, lowering into said hole a bag having a shape corresponding to that of the body to be formed and made of a flexible material which is water-permeable but substantially blocks the passage of the solid particles of the (concrete) mortar and filling said bag with the (concrete) mortar, whereby the bag is subjected to vibrations either during and/or directly after the filling.

Description

iinited States Patent [1 1 Van Weele Apr. 23, 1974 METHOD FOR FORMING A BODY OF CONCRETE OR SIMILAR MATERIAL IN THE SOIL lnventor: Abraham Francois Van Weele,

Brugweg 78, Waddinxveen, Netherlands Filed: June 23,1972

Appl. No.2 265,487

ForeignApplication Priority Data June 25, 1971 Netherlands 7108860 us. Cl 1/5352, 61/53.6, 61/5164,

, 6l/53.7 Int. vCl E0211 5/38, E02d 5/60 Field of Search. 6l/53.64, 53.52, 53.6,

References Cited UNITED STATES PATENTS 2/1970 Lamberton 61-/53.52

3,611,735 10/1971 Daczko ..61/53.64

Primary ExaminerJac'ob Shapiro Attorney, Agent, or Firm--McGlew and Tuttle [57] ABSTRACT A method of forming a body of concrete or similar material in the soil comprises the steps of making a hole in the soil, lowering into said hole a bag having a shape corresponding to that of the body to be formed and made of a flexible material which is waterpermeable but substantially blocks the passage of the solid particles of the (concrete) mortar and filling said bag with the (concrete) mortar, whereby the bag is subjected to vibrations either during and/or directly after the filling.

6 Claims, 3 Drawing Figures PATENTEDAPR 23 I974 FIG.2

FIG.1

1 METHOD FOR FORMING A BODY OF CONCRETE OR SIMILAR MATERIAL IN THE SOIL SUMMARY OF THE INVENTION BACKGROUND AND PRIOR ART The use of bags when forming concrete bodies, usually piles, in the soil is well known in the art. A main reason for the use of a bag is to obtain a casing and/or to keep the (concrete)-mortar from direct contact with the surrounding soil particles or with the underground water, respectively, in order to avoid the detrimental influences of soil particles, or of the underground water, respectively, on the quality of the ultimate body.

The art according to U.S. Pat. No. 3,396,545 recognizes that, that with a suitable selection of the material of the bag and particularly with a suitable choice of the mesh size of e.g., a polyamide fabric, the bag may function as a filter which tends to retain the solid particles of the still flowing (concrete) mortar but permits the passage of the water therein. The advantage of such a filtering effect is to be seen in that the water-cement factor is substantially reduced before the mortar begins to set up. Due to this, the quality of the ultimate body is improved. On the other hand, however, a relatively high water-cement factor facilitates the transportation and the casting of the (concrete) mortar. According to the teaching of the above mentioned U.S. patent, the mortar may thus be handled and put into place with a relatively high water-cement factor, while the setting process may still take place with a low water-cement factor. I

A complicating factor, however, is to be seen in that according to the prior art teaching, the mortar has to be introduced under arelatively high pressure and has to be keptunder saidpressure thereafter during some time in order to have the filtering action take place with certainty prior to the start of the setting process. With DESCRIPTION OF THE INVENTION Now according to the present invention, the above described filtering action may be promoted or made less dependent on the pressure applied to the mortar respectively by subjecting the casting bag to vibrations either during and/or directly after filling. Due to the vibrations, the contents of the bag reach a more fluidized condition. As a consequence the water in the mortar becomes less firmly bonded to the solid particles and is permitted to flow off towards the surrounding soil. The filtering bed of the solid particles of the mortar which, according to the theory of the said prior art U.S. patent is, formed interiorly of the bag wall will, due to the vibration, be brought in a less static condition. By this means the water is readily released and permitted to pass without the filter bed particles themselves passing through the bag wall. Moreover, this effect is uniform through the full depth of the casting bag so that the vertical dimensions of the body to be formed do no longer constitute a limiting factor as with the well-known method used up till now. Experiments have been made, whereby pile bodies formed in accordance with the teachings of the present invention, showed a substantially constant improvement of mechanical strength. This could not be explained only by the improved packing of the material due to the vibration. Therefore, this clearly indicated a uniform filtering effect along the complete length of the casting bag.

For effecting the vibrations a number of needle shaped vibration means may be driven in closely along the exterior of the filled bag and/or into the bag.

A practical and economical, and therefore, preferred method, is particularly suited for the forming of pile shaped bodies. According to this method, tubular vibration means surrounding the casting bag is applied, and by means of this first the hole in the soil is made and then this means is extracted from the soil after the filling of the bag while the bag .is being subjected to vibrations. I

By this method the discharge of the water, which is released during the vibration of the material in the bag, may occur in the most favourable manner, for the discharge of the water then starts from the lower end of the bag and extends gradually upwardly as the 'water is permitted to escape via the gradually upwardly moving lower edge of the tubular vibration means. Thus, the

upper (concrete) mortar, which has not yet been drained and is stillin a readily flowing state, may continue flowing downwardly to occupy the space freed by the setting of the underlying mortar mass.

it is to be noted that it has been known before to form a concrete pile in the soil, whereby the concrete mortar is cast into a hole made in the soil by means of a tube which is finally extracted from the soil while being subjected to vibrations. In that case, however, no bag surrounding the mortar is applied and therefore no filtering action reducing the water-cement factor is obtained. According to the latter well-known method an enlarged foot may be formed on the pile by lifting the tube in the first part of its lifting movement with a relatively low velocity.

With the method according to the invention such an enlarged foot, which favourably influences the load bearing capacity of the pile, may be realized as well, namely by applying a bag which is open at its lower end and which is inserted with its lower end up to a distance from the lower edge of the tube. However, smaller differences in cross-sectional dimensions may also be obtained by differences in lifting velocity in the pile portions which are surrounded by the resilient bag.

The invention also relates to a (concrete) body formed in the soil and obtainedby the application of the method according to the invention.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows a schematic vertical section through a tube having a lost shoe which has just been driven into the soil together with the casting bag with the application of a special vibration assembly, in order to form a pile shaped concrete body;

FIG. 2 illustrates the next phase of the method according to the invention in which the casting bag has been filled with mortar and the vibrating tube has already been extracted through a certain distance from the soil, while the shoe is left in place and FIG. 3 shows the situation after the tube has been fully extracted and illustrates the finished pile body.

DESCRIPTION OF SPECIFIC EMBODIMENTS The invention will be better understood with reference to the illustrative drawings described herein.

A substantially cylindrical tube 1 of a type known per se is provided at its lower end with a so-called lost shoe la and has been driven into the soil by means of a special vibration assembly 2. Said vibration assembly has a central portion 3 which may be clamped around the tube 1 at every desired position by supplying a pressure fluid. The assembly 2 is then lowered by a crane or similar device not further shown. Prior to driving the tube 1 into the soil first the casting bag 4, which is open at its lower end and consists of a fabric of polyamide or polyester, has been inserted into the tube 1. The bag 4 is provided at its lower end with. a stiffening ring 5 and is secured via said ring to the shoe la by means of a number of binding wires 6. The bag 4 is secured at its upper end to a tube section 7 which has been inserted into the upper end of the tube 1 and may be provided with means for suspending a reinforcement structure for the pile body to be formed. The bag is kept drawn taut prior to and during the filling by the tensioning lines indicated 8 which are in engagement with the tube section 7. The bag 4 has its lower edge prior to the filling step at a certain distance, e.g., 1 meter, above the shoe la.

In the situation according to FIG. 1 the bag 4 is about to be filled with (concrete) mortar through the tube section 7 and the schematically indicated filling tube 9.

FIG. 2 shows the situation after the casting bag 4 having been filled and the tube 1 has already been lifted through a certain distance x (e.g., 1 meter) while being subjected to vibrations at a frequency in the order of 500 to 1,000 longitudinal vibrations per minute. The velocity with which said first part of the total lifting movement has been covered is kept relatively low, e.g., in the order of 1 meter per minute. With said moderate lifting velocity the portion of the filling which has been released with the upward movement of the tube has met with a moderate resistance in the surrounding zone of the soil to its tendency to drive out laterally, because of said surrounding zone of the soil remaining strongly under the influence of the vibrations of the lifting tube at said low lifting velocity and therefore remaining in a relatively highly fluidized condition and thereby offering less resistance. In this manner, as appears from the drawing, the lower portion of the mortar filling has expanded to a relatively wide pile foot. In this connection it is remarked that, as hasbeen found by experiments, the pouring bag has stretched in the depth direction during the filling so that the lower edge of the bag after filling has arrived at a shorter distance above the shoe la.

FIG. 3 shows the final stage of the method according to the invention which is obtained when, starting from the situation according to FIG. 2, the tube is lifted through the remaining lifting height y at a higher velocity, e.g., in the order of 5 to 10 meters per minute. With said higher lifting velocity the bag filling has been able to expand substantially less, so that the obtained pile body has an enlarged foot which considerably increases the load bearing capacity of the pile.

It has to be remarked in this respect that from the start of the lifting movement of the vibrating tube 1 the water which is undesirable in connection with the low water-cement factor in view, is released along the complete length of the filled bag from its adherence to the solid mortar particles. However, the discharge of water takes place gradually, via the lower edge of the tube 1 gradually moving upwardly. In each phase of the lifting movement of the tube, the water in the portion of the bag filling which is still surrounded by the tube and already has been released for the discharge, but has not yet been really discharged, keeps said portion of the bag filling in a condition in which it may easily flow and thereby fill the volume released by the expansion of the underlying bag filling. The discharge of the water released by the vibration thereby is postponed to the moment in which the mortar is no longer wanted to flow down.

It is finaly remarked that the filling of the bag and the vibration of it must not be necessarily awaited until the hole has been formed. It might even be preferred to fill the bag as it is lowered with the tube into the soil. This procedure provides a better control of the filling step.

I claim:

1. Method of forming a body of concrete or similar material in the soil comprising: making a hole in the soil; lowering into the hole a bag having a shape corresponding to that of the body to be formed and made of a flexible material which is water-permeable but substantially blocks the passage of the solid particles of the (concrete) mortar; filling the bag with the (concrete) mortar; and subjecting the bag to vibrations acting on its radially outer peripheral surface to compact the filling by flow of excess water of the filling radially outwardly through the side wall of the bag.

2. The method according to claim 1, comprising subjecting the bag to such vibrations initially over its entire length; then progressively reducing, upwardly of the bag, the length thereof subjected to such vibrations.

3. The method according to claim 2, comprising lowering, into the hole, a tube surrounding the bag; and subjecting the tube to such vibrations while extracting the tube out of the soil leaving the bag in the hole.

4. Method of forming a body of concrete or similar material in the soil comprising: making a hole in the soil; lowering into said hole a bag having a shape corresponding to that of the body to be formed and made of a flexible material which is water-permeable but substantially blocks the passage of the solid particles of the (concrete) mortar and filling said bag with the (concrete) mortar; subjecting the bag to vibrations either during and/or directly after filling; applying tubular vibrating means surrounding the bag, first making the hole in the soil extracting said means from the soil while subjecting said means to vibrations after the filling of the bag; and keeping the bag tautly tensioned prior to and during the filling by anchoring the bag at its lower end and securing the upper end of the bag to a tensioning element inserted in the upper end of the tube.

5. The method according to claim 4, which comprises lowering the bag into the tube so far that said bag exsponding to that of the body to be formed and made of a flexible material which is water-permeable but substantially blocks the passage of the solid particles of the (concrete) mortar and filling said bag with the (concrete) mortar; subjecting the bag to vibrations either during and/or directly after filling; applying tubular vibrating means surrounding the bag, first making the hole in the soil; extracting said means from the soil while subjecting said means to vibrations after the tilling of the bag; lowering the bag into the tube so far that said bag extends with its lower edge to a distance above the lower end of the tube, which is still completely inserted in the soil, which distance substantially corresponds to the height of an enlarged pile foot; lifting the tube in the first part of its lifting movement with a lower velocity than in the remaining part of the lifting movement; and forming said enlarged pile foot.

Claims

5. The method according to claim 4, which comprises lowering the bag into the tube so far that said bag extends with its lower edge to a distance above the lower end of the tube, which is still completely inserted in the soil, which distance substantially corresponds to the height of an enlarged pile foot, lifting the tube in the first part of its lifting movement with a lower velocity than in the remaining part of the lifting movement, and forming said enlarged pile foot.

6. Method of forming a body of concrete or similar material in the soil comprising: making a hole in the soil; lowering into said hole a bag having a shape corresponding to that of the body to be formed and made of a flexible material which is water-permeable but substantially blocks the passage of the solid particles of the (concrete) mortar and filling said bag with the (concrete) mortar; subjecting the bag to vibrations either during and/or directly after filling; applying tubular vibrating means surrounding the bag, first making the hole in the soil; extracting said means from the soil while subjecting said means to vibrations after the filling of the bag; lowering the bag into the tube so far that said bag extends with its lower edge to a distance above the lower end of the tube, which is still completely inserted in the soil, which distance substantially corresponds to the height of an enlarged pile fooT; lifting the tube in the first part of its lifting movement with a lower velocity than in the remaining part of the lifting movement; and forming said enlarged pile foot.