GB2361259A - Method of mounting a container at least partially in the ground - Google Patents

Abstract

Method of mounting a container at least partially in the ground comprising the step of backfilling the space between the suspended container and a recess in the ground with a flowable filling substance to a backfilling level such that said container does not float away from its suspended position, the step of backfilling comprising two or more backfilling stages with at least partially setting of said flowable filling substance between said stages. Also described is a method for mounting a container in a recess in the ground, comprising the step of immersion of the container up to a first backfilling level in the filling substance, followed by further immersion of the container in the filling substance after at least partially setting of the filling substance up to the first backfilling level.

Description

---1.1 1 2361259 METHOD FOR MOUNTING A CONTAINER AT LEAST PARTIALLY IN THE

GROUND This invention relates to a method for mounting a container at least partially in the ground and particularly but not exclusively to a method for embedding a container such as a tank or a pit at least partially in a concrete or other filler material.

Current practice in the construction of underground or embedded objects such as pits, lift wells, basements, swimming pools, etc. requires various steps when constructing these objects from a concrete material. First, a metal framework is constructed on-site which is encapsulated in a temporary wooden casing. This casing is subsequently supported and filled with a concrete material. After the setting of the concrete material the casing is removed and the underground or embedded object is ready for use. This method of construction is labourious, costly and rather inefficient.

An aim of the present invention is to provide improvements in relation to one or more of the above problems, or one or more improvements generally.

According to the invention there is provided a method for embedding a container at least partially in a flowable filling substance as defined in the accompanying claims.

In an embodiment of the invention, the recess may comprise a hole or cavity of a suitable size dug in the ground. The recess may be treated or sealed to prevent the soil from affecting the flowable filling substance. The recess is preferably of a suitable size to allow the clearance between the container and the walls of the recess to be readily filled with the flowable filling substance.

According to the invention, after providing a recess in the ground and providing a container therein with at least space for a degree of clearance all round the container sufficient for a layer of flowable filling substance, suspension means may be provided for suspending said container inside said recess with suitable clearance existing at least around a substantial proportion of the periphery of the container. Said suspension means as herein described may also comprise any suitable means for positioning the container at a suitable distance from the walls of the recess. Said positioning means may comprise one or more support members which support the container from the bottom of the recess. Suitable support members may be formed by spaced bricks or beams.

In another embodiment of the invention, the step of backfilling may comprise two or more subsequent stages, with at least partial setting of said flowable filling is substance between said stages. The first stage may comprise backfilling the clearance with a flowable filling substance to a suitable backfilling level such that the container does not float away from its suspended position. The suspension means prevent the container from sinking into the flowable filling substance at this stage.

The suspension means comprise support beams which are connectable to said container, the support beams extending at least across the recess. The container may be supported on one or more spaced support elements such as concrete pads provided at ground level alongside said recess on at least two sides thereof. The support elements may be provided outside the recess, preferably outside the outer perimeter of the recess. The support beams may be supported from one or more of said spaced support elements. In this way the suspension means may be formed.

When backfilling the clearance, the quantity of the flowable filling substance (when in the form of a fluid settable substance such as concrete) provided in the recess may be such that if the container were not positioned and/or suspended the container would sink into the flowable filling substance. If the recess were filled with a larger quantity than the aforesaid quantity, this would cause the flowable filling substance to lift the container such that the container would be floating in the fluid or semi-fluid filling substance. This would be undesirable since the container would not be positioned accurately. Usually a further quantity of flowable and settable filling substance is then added after the first amount has set or partially set.

It is possible to calculate the maximum backfilling level of the flowable filling substance to which the recess can be filled in order to prevent the container from floating or beginning to float, as follows.

The container would sink if the weight W of the container is more than the buoyancy or upthrust L provided by the displacement of the filling substance, or W>L. The weight of the container is def ined by its mass m and the gravitational acceleration g as W=m.g. The upthrust L is defined by L=V.g.psubstance where psubstance is the density of the flowable filling substance and V is the immersed volume of the container. By combining the two above expressions for the weight W and the upthrust L, the container sinks if the following condition applies:

M > V.Psubstance.

For containers of certain shapes, the immersed volume V of the container may be defined as V=h.A where A is the surface area of the underside of the container and h is the height of the backfilling level measured from the underside of the container. This definition of the immersed volume is valid for a wide range of containers with an immersed volume of a rectangular, cylindrical or cubic shape. Alternative expressions for the immersed volume may be derived for containers with different immersed shapes.

By combining the definition of the immersed volume V with the above condition, the filling substance level height for which the container sinks is presented by the condition:

h < m1A.psubstance In practice, in an embodiment of the invention. the above condition is applied when constructing an embedded container or a container mounted in the ground according to a method of the invention. The clearance between the container and the recess is filled with the flowable filling substance (in the form of a flowable composition, whether fluid or semi-fluid, or dry granulate) up to or just below a backfilling level as defined by the above is expression where the backfilling level h is measured from the underside of the container or alternatively is measured from the bottom of the recess taking into account the clearance between the bottom of the recess and the underside of the container. After setting or at least partial setting of the filling substance up to the backfilling level, the recess is further filled in one or more stages with the filling substance.

If the clearance is initially filled beyond said first backfilling level, the container would float. This would cause the container to move from its required position, or alternatively this would cause unnecessary strain on the positioning means or the suspension means.

In an alternative embodiment of the invention the container may be supported or at least positioned by spaced support elements situated inside the recess. Suitable support elements may be formed by bricks or beams.

The container preferably comprises a material which is impermeable to the flowable filling substance that is used for backfilling the clearance between the recess and said container. The container may be made of steel, a plastics material or wood. In an advantageous embodiment, the container is made of steel thereby providing structural support and strength to the construction. This is :,W^ particularly important when constructing lift wells or pits for servicing vehicles. In a preferred embodiment the container is open at the top side.

The filling substance is flowable so as to accommodate itself to the clearance and fill at least the lower parts of the clearance between the container and the recess, and may comprise a concrete materi al, cement, a granulate material, a plastics material or a mixture of two or more of the aforesaid materials. By using a filling substance of a relatively low density, the backfilling level at the first backfilling stage may be relatively high. This has the advantage that immersion of the container up to a second level in a subsequent backfilling stage may not be necessary. Alternatively, by using a filling substance of is a relatively high density, the first backfilling level may be relatively low.

According to another aspect of the invention there is provided a construction comprising a container mounted in the ground according to a method as hereinbefore described.

This construction is particularly advantageous in the construction of underground or embedded objects such as basements, swimming-pools, pits and lift wells.

Embodiments of the invention provide a method in which a working tank or pit or like construction, which is preferably of watertight construction so as prevent the ingress of water from the surrounding land in use, is mounted within a constructed hole or recess in the ground by a method including the following steps.

Firstly, the hole or recess is constructed at an oversize dimension whereby the container in the form of a tank or pit can be placed therein with clearance at all or most locations. The pit or tank may also be suspended. It may also be suspended by positioning means consisting of overhead support means. The support means comprises structure straddling the top opening of the hole or recess within which the tank or pit is to be suspended. Support elements may be provided on or in the ground at spaced locations along opposite sides of the rece.ss or hole. Beams or the like may be provided between these support elements, from which the tank or pit is suspended within the recess or hole, utilising suitable attachment means.

Then, with the tank or pit positioned within the recess or hole, a filling substance in the form of a filling medium, preferably concrete, is poured or placed into the clearance spaced between the tank and the walls of the hole so as to fill same. This backfilling operation is preferably performed in at least two stages. In the case where liquid concrete is poured into the clearance space, the first stage of backfilling is to fill the space at the bottom of the tank between the base of the tank and the bottom of the hole. This stage may extend to partially backfilling the side and end portions of the recess also, but only to an extent determined by the formula as hereinbefore described relating to the first liquid level height. The extent of backfilling adopted is that which, having regard to the weight of the tank or pit and its buoyancy in the liquid or partially liquid concrete, produces only an acceptable or limited or zero lifting of the tank or pit, such that if the positioning means were not present, the tank or pit would sink into the filling medium. Complete backfilling of the recess around the tank with liquid concrete could cause same to float upwards and to interfere with the overhead support structure. By carrying out a backfilling operation in at least two stages in which the concrete inserted in the first stage is allowed to set or at least partially set before commencing the next stage, the process is facilitated and without the need to fill or partially fill the tank with weights or water for example. This allows a less complicated and more efficient installation of the tank or pit.

1-1 The embodiments of the invention provide significant technical simplification of the operation of providing a sealed vehicle maintenance pit below ground level at automotive servicing facilities by a constructionally simplified method requiring negligible on-site constructional work. The technique is applicable to many other related site operations such as the construction of pits for lift wells. The prior art proposes that these latter constructions be formed by a fabrication technique on-site, with significant technical and logistical difficulties. The embodiments of the present invention enable all fabrication operations (the construction of the tank or pit itself) to be carried out off-site in a fabrication workshop, followed by transportation to the site, simple suspension on support pads provided alongside a plain hole dug in the ground, followed by back filling in two or more stages with concrete. All these operations are ones which are conveniently and easily carried out by relatively unskilled site workers.

An aspect of the embodiments of the invention described below relates to the construction and mass and support of and for the pit and tank itself. These factors are inter-related by the physical requirements of the tank.

These include the simple need to exclude water from the adjacent ground and to remain stable and structurally sound during the life of the apparatus. Usually, the tank itself will be constructed from an inexpensive fabrication material such as mild steel, but a synthetic material including polymers may be suitable in certain cases. The strength and weight and rigity of the tank itself are technically inter- related to the filling material which is usually concrete and indeed to the consistency of the concrete when placed or poured into the backfilling region around the pit, since this affects buoyancy of the tank during the backfilling operation.

In the embodiments of the invention significant variations may be employed in the method for supporting the pit or tank within the hole or recess prior to and during the backfilling operation. According to the facilities available at the site, the support means for the tank or pit may vary significantly. For example it is envisaged that the method might very conveniently employ the use of a fabricated support structure (for example comprising a pair of beams or trusses to be laid lengthwise of the hole or recess in the ground to provide an extended structure) spreading the weight of the tank at each side of the hole or recess, and having a series of transverse links each of sufficiently rigid construction to support its share of the weight of the tank prior to setting of the concrete, and is connected to the tank by suitable detachable means which could be length-or-position-adjustable to enable the suspended pit or tank to be exactly positioned according to need. As soon as the tank is sufficiently supported by its filling as to be stable (which might be after the first stage of concrete filling has been effected and the concrete has at least partially set), the support structure could then be removed.

An embodiment of the invention will now be described as an example only and with reference to the accompanying drawings in which:- Fig. 1 shows a construction in a diagrammatic crosssectional view, and Fig. 2 shows the construction as shown in Fig. 1 in a diagrammatic plan view.

Figs. 1 and 2 show a construction 10 according to the invention comprising a container 11 suspended in a recess 12 in the ground by means of a suspension 14 according to a method as hereinbefore described. The recess 12 is of a dimension such that when the container 11 is located therein there is at least space for a degree of clearance all round the container 11 sufficient for a layer of flowable filling substance 16.

The suspension means 14 comprises one or more spaced support beams 18 which are connectable to the container 11.

The support beams 18 extend at least across the recess 12.

The support beams 18 are supported from the ground by one or more support elements 20 in the form of rectangular concrete pads.

The container 11 as shown in the drawings of Figs. 1 and 2 has an immersed rectangular shape at least up to the first level h, in the filling substance 16. The immersed volume is defined by the formula as hereinbefore described and the maximum level for h, can thus be defined by the condition as hereinbefore described.

The container 11 is mounted in the ground as follows. A recess 12 is constructed in the ground. The recess 12 is of a dimension such that when the container 11 is located therein there is enough clearance all round the container for a layer of filling substance 16. Then, the container 11 is located inside the recess 12 by means of the suspension 14. The clearance is then backfilled in two stages with a flowable filling substance 16. First, the clearance is filled with the filling substance 16 to a backfilling level h, such that said container does not float away from its suspended position. After setting or at least partial setting of the filling substance 16, the clearance is further filled with the filling substance to a level h, Thereafter the suspension means 14 are removed leaving the support elements 20 in the ground.

Claims (16)

1 Method of mounting a container at least partially in the ground, the method comprising:

a) preparing a recess in the ground; b) providing a container or the like hollow body to be located in said recess, said recess being of a dimension such that when said container is located therein there is at least space for a degree of clearance all round the container sufficient for a layer of flowable filling substance; c) providing suspension means for suspending said container inside said recess with said clearance existing at least around a substantial proportion of its periphery; and d) said method further comprising the step of ba--filling said clearance with a flowable filling substance to a backfilling level such that said container does not float away from its suspended position.

2. Method of mounting a container at least partially in the ground comprising the step of backfilling the space between the suspended container and a recess in the ground with a flowable filling substance to a backfilling level such that said container does not float away from its suspended position.

3. Method according to claim 1 or 2, characterised in that the step of backfilling comprises two or more backfilling stages, the first stage comprising backfilling to the backfilling level, with at least partially setting of said flowable filling substance between said stages.

4. Method according to any of the preceding claims, characterised in that the method further comprises the step of supporting said container on one or more spaced support elements provided at ground level alongside said recess on at least two sides thereof.

5. Method according to any of the preceding claims, characterised in that the suspension means comprise support beams which are connectable to said container, the support beams extending at least across the recess.

6. Method according to any of the preceding claims, characterised in that the container is of such a shape that the immersed volume of the container at least up to the backfilling level is defined by V=h.A wherein V is the emerged volume, A is the surface area of the underside of the container and h is the height of the backfilling level measured from the underside of the container.

7. Method according to claim 7, characterised in that the height of the backfilling level h is smaller than a value which depends on the mass of the container, the density of the filling substance and the surface area of the underside of the container.

8. Method according to claim 7 or 8, characterised in that the backfilling level h is defined as h < M/A. psubstance where m is the mass of the container and psubstance is the density of the flowable filling substance.

9. Method according to any of the preceding claims, characterised in that the method further comprises the step of removing the suspension means after setting or at least partial setting of the flowable filling substance.

10. Method according to any of the preceding claims, characterised in that the container is of an approximate rectangular, cubic or cylindrical shape.

11. Method according to any of the preceding claims, characterised in that the container consists of an impermeable container such as steel, a plastics material or wood.

12. Method according to any of the preceding claims, characterised in that the filling substance comprises a concrete material and/or a granulate material and/or a resin and/or cement.

13. Method for mounting a container in a recess in the ground, comprising the step of immersion of the container up to a first backfilling level in the filling substance, followed by further immersion of the container in the filling substance after at least partially setting of the filling substance up to the first backfilling level.

14. Method as hereinbefore described and with reference to Figs. 1 and 2 of the drawings.

is. Construction comprising a container mounted in the ground according to a method of any of the preceding claims.

16. Construction according to claim 15 and as shown in Figs. 1 and 2 of the drawings.