FI68877C - ANALYSIS OF THE MARKETS AND ENVIRONMENTAL MARKETS - Google Patents

Description

DEVICE FOR FORMING A VERTICAL GROUND - ANORDNING FÖR

MARKETING AUTHORIZATION OF MARKETS

68877

The present invention is applicable to the use of strips, ditches (prefabricated drains) for reinforcing aqueous, fine-grained and poorly water-permeable soils such as clay, silt, etc. by removing water from the soil by vertical drainage and thereby reducing the water content of the soil. Thus, the bearing capacity of the soil is improved, the expected depressions are accelerated, while the shear strength of the soil is increased.

Various strip guards have been developed for vertical drainage, consisting, for example, of a profiled strip of plastic, about 10 cm wide, and of porous paper or other similar filterable material wrapped around it, which is permeable to water.

The strip riser is installed in the ground by pushing it to the desired depth, usually vertically, using a special plug. The strip guard is inside the plug tube and the lower end of the strip guard is anchored in place with a special anchor. After installation, the plug is pulled out, leaving the strip upright in the ground. The strip guard is cut at a suitable height. Such strip guards are placed at suitable distances from each other, depending on the ground conditions and objectives, e.g. every 1 ..... 2 m in the area to be strengthened.

Water from the soil is filtered through the porous paper into the channels in the strip ditch, rising up and draining away.

Vertical drainage can also be used to dry and strengthen a layer of clay or mud on the bottom of the sea or lake, which can be tens of meters thick. Vertical drainage is necessary when it is intended to fill, for example, the bottom of a lake or sea at that point, for example, for the construction of a road, railway or even an airport. If the soft, compressible clay layer is not drained before filling, it will take decades for the compressible layers to sink due to the filling and other loads on them. Vertical ditching can speed up the subsidence so that it takes place in a year or two or even a few months, depending on the bottom ratios and the distances between the vertical ditches. The magnitude of the depressions can be several meters, depending on the ground conditions and the load.

The invention thus relates to a device for forming a vertical drain in the ground, comprising a plug-in plug inserted into the ground, which carries a strip guard inside it, the lower end of which is provided with a plate-like anchor resting against the lower end of the plug tube and holding the strip guard in place.

Until now, there have been difficulties in ensuring that the anchor at the lower end of the strip guard and thus also the strip guard remain in place when the plug tube is lifted upwards. Difficulties have arisen especially in those cases where lius-kapysti drainage has had to be done on the so-called “sensitive clay” (“kvick lerä” in Swedish). This is because, for example, in the case of penetration of the filling on the ground, the anchor plate bends against the lower end of the plug.

When the plug is now lifted upwards in the delicate clay, the anchor plate does not stick to the clay, but rises with the plug.

The object of the present invention is to eliminate the above-mentioned drawback and to ensure that the anchor plate adheres to even sensitive clay. The invention is characterized in that the lower end of the plug tube has at least one bag-like pressing member between it and the anchor, which can be made to bulge by means of a pressure medium so as to push the anchor out of the lower end of the plug tube and spread it to the open position. Thus, the surface of the anchor that adheres to the surrounding ground expands considerably so that the anchor plate remains securely in place when the plug tube is lifted.

The invention will now be described by way of example with reference to the accompanying drawing, in which

Fig. 1 shows a cross-section of the lower end of the plug tube with the anchor attached to the lower end of the strip guard.

Fig. 2 shows the lower end of the plug tube after it has been pushed into the ground and the anchor has bent against the lower end of the plug tube.

Fig. 3 shows the plug tube in its lower position with the anchor extended.

In the drawing, reference numeral 1 denotes the lower end of the plug tube, inside which there is a strip guard 2. A plate-like anchor 5 is connected to the lower end of the strip guard 2 by means of a loop 7 and a connecting piece, i.e. a support plate H.

According to the invention, the lower end of the plug tube 1 has two bag-like pressing members 3 located between the lower end of the plug tube and the anchor 5. The bag-like pressing members 3 are connected via a channel 6 to a source of pressure medium on the ground. By means of the pressure medium, the pressing elements are caused to bulge to the position shown in Fig. 3, whereby the anchor 5 opens.

Fig. 1 shows a situation in which the plug tube 1 is in its upper position and the anchor plate 5 and the support plate 4 are fastened to the lower end of the strip guard 2 by means of a loop 7. Figure 2 shows a situation in which the plug pipe 1 has penetrated into the ground and the anchor plate 5 has bent against the lower end of the plug pipe. Figure 3 shows a situation in which the plug tube 1 is in its lower position. The bag-like pressing members 3 are filled with a pressure medium so that they have bulged out and pushed the anchor 5 out of the lower end of the plug tube and spread the anchor to the open position. When the plug tube 1 is now pulled up, the anchor 5 securely grips the surrounding soil, whether it is sensitive clay or other soft soil. »The pressure members 3 are depressurized and retracted to the position shown in Figures 1 and 2.

It will be apparent to those skilled in the art that various embodiments of the invention may vary within the scope of the claims set forth below. Thus, the operation of the bag-like pressing members 3 can be effected either hydraulically or pneumatically. The number of bag-like pressing members 3 may vary »It is preferred that their number is even and that they are located symmetrically with respect to the axis of the plug tube 1. Thus, the anchor 5 is made to open evenly.

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Claims (2)

688 77 An apparatus for forming a vertical drain in the ground, comprising a plug-in plug (1) inserted into the ground, which carries a strip guard (2) inside it, the lower end of which is provided with a plate-like anchor (5) resting against the lower end of the plug. in place of the strip guard, characterized in that at the lower end of the plug tube (1) there is at least one bag-like pressing member (3) between it and the anchor (5), which can be inflated by the pressure medium so that it pushes the anchor off the bottom end of the plug tube and spreads it open. Device according to Claim 1, characterized in that the bag-like pressing elements (3) have an even number and are located symmetrically with respect to the axis of the plug tube (1).