NL9300394A - Expansion body - Google Patents

Abstract

Expansion body for constructions located in the ground, comprising a pliable, substantially elongate sheath which delimits an internal, closed space which can be connected to a source of pressurized fluid to expand the body by means of inflating the sheath, the sheath being based on a fabric or cloth of high-quality, tension-proof and stiff plastics or mineral fibres.

Description

Expansion body.

The present invention relates to an expansion body for in-ground structures, with a pliable substantially elongated casing defining an internal enclosure which is connectable to a source of pressure fluid for expanding the body by means of the bulging of the mantle.

Such an expansion body is known, for example, from EP-A-0079875. It describes an expansion body with a sheath of steel plate, which sheath has initially been ingeniously folded, to be introduced into the ground as a more or less thin, slender rod. The casing is then filled with a pressure fluid, for example high-pressure concrete, whereby the casing unfolds into a somewhat elongated sausage while the surrounding soil is pressed away. Anchoring rods are then inserted into the concrete located inside the jacket, and after the concrete has hardened, a reinforced concrete column remains, which can be used as anchoring for foundation purposes. In addition, the concrete column has a diameter which is considerably larger than the initial diameter of the expansion body.

A disadvantage of this known expansion body is the relatively complicated construction of the steel sheet jacket. This jacket must be pleated in a special manner, and the sealing of the jacket also requires special attention. In addition, the tensile strength, in particular that for bearing the shell tension of the jacket, is limited, due to the low permissible thickness of the steel sheet used. This means that if during the expansion of the steel jacket the ground locally around the jacket offers insufficient back pressure, for instance as a result of local deviations in the soil structure, there is a risk of locally large deformations and consequently premature failure of the jacket. In practice, therefore, only jackets of relatively short length are used, and for greater required lengths several jackets are coupled one after the other.

Furthermore, German expansion patent 618490 discloses an expansion body with a jacket of stretchable material, for example rubber. Such an expansion body can be introduced into the ground without folds of the jacket, after which the jacket is then pumped up under stretching. Here too there is a risk of uneven deformation and thus premature failure due to uneven support from the surrounding soil during inflation.

The object of the invention is to provide an expansion body of the aforementioned type, which is efficient to manufacture and use, and which is highly insensitive to uneven back pressure of the soil surrounding the jacket during the expansion of the body. In accordance with the present invention, this object is achieved with a jacket which is constructed from a fabric or cloth of high-quality fibers with high tensile strength and stiffness. Fabrics or cloth of, for example, glass fiber, carbon fiber, aramid (kevlar) fiber or dynema fiber, but also other mineral or plastic fibers are eligible for this. A jacket made of such a fabric or cloth has a particularly high relative tensile and shear strength with relatively little deformation, while the jacket is particularly easy to fold and unfold. Starting from, for example, a tube-like fabric, the jacket can be manufactured by simply joining the ends thereof together with, for example, a generally available steel clamping ring. It is even easier to tie a knot in the joined end. One of the ends of the jacket can easily be clamped liquid-tight on a pipe with which the expansion body can be introduced into the ground, and with which the pressure fluid can then be injected into the jacket. Depending on the application, the necessary thickness of the fabric or cloth for assembling the jacket is largely free to choose. As a result, the use of relatively long jackets is possible even in soil with a strongly uneven structure.

Furthermore, the use of a fabric or cloth according to the present invention provides the possibility of integrating the jacket with the conventional driving rod connected to the jacket. The insertion rod can thus be designed as a hollow tie rod, which is directly connected to the jacket in a transferring manner. With regard to this embodiment, the separate reinforcement of the concrete after pressing the expansion body is now no longer necessary. The jacket and insertion rod of the expansion body now actually form the (external) reinforcement. For example, sheath and insertion rod are made from the same tubular cloth woven so that the sheath is wider than the insertion rod connecting thereto, the hose portion forming the rod portion being impregnated with a conventional synthetic resin to provide its own stiffness to the rod portion.

Another advantage obtained with the present invention is the ability to recover all or part of the expansion body. All this will be further elucidated on the basis of the figure description below. For this purpose, the jacket can be formed, for example, from a separate inner and outer jacket, the outer jacket consisting of a low-quality material, and the inner jacket being designed in accordance with the present invention.

In the following, the invention will be further elucidated on the basis of a non-limiting exemplary embodiment shown in the attached figures.

Hereby shows:

Figure 1 is a side view of a first embodiment of the expansion body, with integrated jacket and insertion rod;

Figure 2 shows an application example of the body; and

Figure 3 shows a view corresponding to figure 1 of a second embodiment of the expansion body.

Figure 1 shows an expansion body 1, formed by a jacket 2 and a hollow tube 3 integrated therewith. The jacket 2 here is partly broken away, and consists of a fabric of glass fiber or dynema fiber. The hollow tube 3 consists of the same fabric, but impregnated with a conventional epoxy resin. The expansion body 1 is woven in a hose-like manner, such that the jacket is considerably wider than the tube 3. At the free end, the jacket 2 is sealed with the aid of a hose clamp 4. Here, the edge of the jacket 1 is simply joined, after which the hose clamp 4 is pulled around the casing. However, it is possible to shape the sheath during weaving so that it narrows towards the free end. Sealing the free end is then even more facilitated. Because casing 2 and pipe 3 merge smoothly, it is now possible to couple the pipe 3 directly to the body to be anchored, for example a sheet pile wall 5 in a construction pit 6, as shown here in figure 2.

Figure 3 shows another expansion body 1, with an inner jacket 2a and an outer jacket 2b. As shown, the expansion body has already expanded. The outer jacket 2b consists of a relatively low-quality material, intended only for lining the occupied space. The inner sheath 2a consists of the fabric or cloth of the present invention. This inner jacket 2a is shown only partially expanded. A tube 6 is connected to the inner jacket 2a, with which a pressure fluid can be pumped into the inner jacket 2. This tube 6 is surrounded by a subsequent tube 7, which is connected to the outer jacket 2b, and with which a fluid can be introduced into the outer jacket 2b. The use of this expansion body according to the invention is as follows:

After the expansion body 1 has been inserted into the ground in the folded-in state, wherein the jacket has assumed a folded-in, slender shape, for instance according to figure 1 of EP-A-0079875, pressure fluid is pumped through inner tube 2a, through which the inner and outer jacket 2a and 2b, respectively, expand jointly while pushing away from the surrounding soil, until a cavity in the soil is formed in accordance with the contour of the outer jacket 2b according to Figure 3. The prevailing internal pressure in the expansion body is then only carried by the inner jacket 2a, which is considerably stronger and stiffer than the outer jacket 2b. For this expansion of the body 1, for example, water or a supporting liquid is pumped into the tube 6. Subsequently, concrete or groud is pumped into the outer jacket 2b via tube 7, with simultaneous outflow of the liquid from the inner jacket 2a via tube 6. As a result, the inner jacket 2a deflates, causing it to collapse again. During this process of deflating the inner jacket 2a by pumping liquid in through tube 7, a certain amount of pressure can be maintained on the liquid inside the inner jacket 2a, to support the outer jacket 2b by pumping in through tube 7 concrete. Figure 3 shows an intermediate phase of this process, in which the inner jacket 2a has already partially emptied via tube 6, and the volume that has flowed out of the inner jacket has been occupied by liquid flowing in via tube 7. When the inner jacket 2a has (almost) deflated, it can be pulled out together with the tube 6 via the tube 7. As a result, the high-quality inner jacket 2a can be reused.

Following the embodiment variant according to figure 3, an expansion body could also be used, wherein in combination with the tube 7 with a tube 6 inserted therein, only a single jacket 2a connected to the tube 6 is used. As soon as the surrounding soil has been displaced to the desired cavity with that jacket 2a, the then uncoated cavity can be filled with grout or concrete by means of tube 7, while the jacket 2a is being emptied. Again, the jacket 2a can be removed together with the tube 6 from the tube 7, for reuse.

Optionally, the expansion body can be further strengthened by wrapping pulling belts extending in the longitudinal direction thereof around the jacket, for instance according to the embodiment in figure 5 of EP-A-0112316.

In addition to the application for relatively short anchoring bodies, the invention is also suitable for the on-site production of (concrete) columns extending over long lengths to replace conventional piles. Despite the danger of large variations in the soil composition over the length of such a pile, usually more than ten meters, the expansion body according to the invention is extremely suitable using a fabric or cloth of particularly tensile and rigid fibers. With regard to this application, recovery of the high-quality jacket is again possible, in a manner according to the above description in connection with Figure 3.

Optionally, for the purpose of recovering the high-quality jacket, the liquid-end-sealed free end thereof can be easily detachable. After expanding the expansion body and releasing that free end, the jacket can then be pulled away in the direction of the opposite end around the liquid filling (for instance concrete or groud). The easy pliability of the fabric or cloth of the jacket allows this.

Claims (5)

1. Expansion body for in-ground structures, with a pliable substantially elongated casing defining an internal enclosed space communicable with a source of pressure fluid for expanding the body by bulging the casing, with characterized in that the jacket is based on a fabric or cloth of high-quality tensile and rigid plastics or mineral fibers. 2. Body as claimed in claim 1, wherein a relatively thin, elongated, hollow pull rod connects to the jacket, and the channel enclosed by the hollow rod communicates in liquid with the cavity bounded by the jacket, characterized in that the tie rod and the jacket is integrated. Body according to claim 1 or 2, characterized in that the jacket is made of glass fiber, carbon fiber, aramid fiber or dynema fiber. 4. Body as claimed in any of the foregoing claims, characterized in that the jacket is composed of a separate inner and outer jacket, the outer jacket being made of relatively low-quality material, and the inner jacket easily, for example, from the outer jacket for the supply of pressure fluid. can be removed. 5. Body according to any one of the preceding claims, characterized in that the jacket is formed from a relatively wide fabric or cloth hose, the ends of which are joined together.