DE4024245A1 - Sealing system for old rubbish dump - has mines trough-section gallery below to form inclined sealing dish - Google Patents

Abstract

The sealing system is of, an old rubbish dump, using an inclined dish forming the base seal and inserted under the dump. This dish is formed by mining a gallery under the dump with a trough-shaped working face. The gallery can then be backfilled fully and at adjustable density, using suitable building material, and an inspection shaft can be formed at the lowermost point, to check for escape of pollutants or ground water penetration. ADVANTAGE - Protection against escape of poisonous matter into subsoil etc.

Description

The procedure is one way of taking an alt last, e.g. B. against by a suitable base seal Groundwater pollution-protected landfill, one according to today's technology, tight and controllable sealing to manufacture.

As of 1989 there is in the Federal Republic Germany 48 377 sites suspected of contaminated sites, in which according to current knowledge up to 78 different, z. T. highly toxic or other substances that are hazardous to health can occur (see Jessberger, H. L .: exploration and remediation of contaminated sites, P. 3 and p. 19 ff., 6th Bochum Contaminated Sites Seminar 1990, Publisher A. A. Balkema / Rotterdam / Brookfield / 1990). In the DDR and abroad must with a huge number similar ge dangerous contaminated sites are to be expected for which protection there is a need. The hazardous substances are e.g. T. able in turn to react chemically with each other and others Form hazardous substances.

Contaminated sites can e.g. T. not disposed of or with conventional Funds to be renovated. One only knows for these problem cases the possibility of securing against the occurrence of damage substances into the groundwater.

There are already a number of process technologies for this, e.g. B. Solidifications in the form of physical, chemical or thermal consolidation, or hydraulic measures, by changing the flow direction of the groundwater or Encapsulation with the help of surface sealing, vertical len sealing walls and subsequent basic seals (see H. L. Jessberger a. o. a. O., p. 6).

The described invention forms part of the subsequent basis seals. According to the current state of knowledge, there is ei ne series of proposals based on the fact that z. B. subsequently introduces side sealing walls that are up to a sealing, natural layer or in a subsequent one Lich manufactured basic seal from a sealing layer from minerals or from building materials in connection with  reach into a plastic film.

The problem with the known proposals is that Sealing difficulties in the area of the interface of Sealing walls and basic sealing are expected and that it e.g. At the moment there is no plastic film that is permanent compared to the Abundance of possible chemical substances their tightness holds. The invention is based on the requirement, we This is how a stylish basic seal for high-risk substances should be look that they have any leakage of pollutants prevented from the landfill into the groundwater, but also that Safe access to groundwater. In addition, must be verifiable, which and what amounts of pollutants between the base seal and landfill to to be able to dispose of. The same applies to any incoming Ground or surface water.

In addition, it must be possible to determine whether the basic seal is actually tight and there must be the possibility collect hazardous substances escaping from leaks to locate their exit points and, if necessary, a post seal.

Finally, the sealing process for contaminated sites if possible with the help of known, proven techniques be led to the risk of failure and the To minimize costs.

This object is achieved in that ent speaking of the patent claims as a subsequent basis seal an inclined sealing bowl with the help of a mining hollow strut with full offset becomes. The struts of the trough strut can, must, above ground but at least above the level of the highest groundwater stand.

The mining process in the longwall can be with known, berg male techniques are performed, so cutting or peeling. Its selection depends on the nature the soil layers in which the longwall must run. Perhaps slope stabilization must be carried out. For that too there are best mining practices. They may require Liche still on the flanks of the hollow strut drive from middle towns to from there in the fall of the  Strebs to make holes in the slope for strengthening. Known or still to be used for the progressive face construction conceiving special blow-off designs can be used, depending on the type of hanging layers and other requirements.

Should a plastic film for the present Ver application on the market, all of which are fatigue strength meets requirements, this could also be done in one a longwall area to be designed in accordance with the expansion to be brought.

The actual sealing element becomes more homogeneous in the face Filled fully offset in sufficient thickness. As an offset material may come from conventional mining building materials in question, e.g. B. Hydro-anhydrite used in the manufacture of Underground dams become gas-tight, even at the seams of the Contribution paragraphs. If necessary, there are also other waterproofing fillers necessary.

Proven mining methods are known for the introduction, either pneumatically or hydraulically or as a combination from both. If necessary, however, other filling techniques are required - depending on the type of filler.

It is important that when inserting the full offset seal bowl no edges to create punching effects close, because this to destroy the sealing offset, so too Permeability. This must be done especially in the Transition areas Streb-stretch must be respected. Stretches cross-sections that go beyond the thickness of the offset hen, are therefore with the material from which the floor there layers, or with a material of the same To fill strength properties.

The in the longwall operation or in the required Strec Mining gain must be removed and if necessary to be stored on the contaminated site.

During the time the sealing bowl is manufactured, Measures to control groundwater necessary. Likewise one should go to the above-ground struts through hiking tents or similar and over the contaminated site in whole or in part by a suitable cover film for the entry of rainwater prevent.

Have the bowl-shaped seal and its inclination  the sense that possibly circulating pollutants in the bowl or waters find their way to the deepest. It is true enough apparently that the slope of the trough strut from the flanks to the axis of the slope of the base seal of rock heaps corresponds. But it is also determined by the depth, in that of the hollow strut due to the nature of the Han end layers must submerge.

Also for the degree of misalignment the sealing bowl is presumably the slope of the base seal of rock heaps sufficient.

The production of the geometric shape of such a seal bowl with the help of a longwall operation is mining technology and measurement-technically unproblematic and state of the art.

The fresh air supply for mining work and their disposal (weather management) can be carried out in compliance with the Underground mining usual procedures and safety aspects respectively. If necessary, facilities for cleaning the weather necessary before entering the atmosphere. Also for handling with substances hazardous to health in the air we breathe or in Skin contact is a mine defense method, but also other tech techniques can be used.

Climatic difficulties are due to the low depth, in which the activities take place, probably not to be expected, but possibly also with known underground technology to master.

The revision located at the lowest point of the sealing bowl shaft (inner inspection shaft) must be accessible and allows pollutant checks to be carried out and, if necessary, Dispose of pollutants and / or water.

The drainage provided under the sealing bowl will be on before bringing the full offset out of the longwall or the Mul made the route and has the task of still appearing trapping leaking media under the seal. She directs it into another inspection shaft (outer Inspection shaft), which is equipped just like the one in our inspection shaft. It consists of inlet pipes that parallel to the face of the face, d. i.e. with dip to the trough axis to be built in. These flow into a collector, which in the Trough section runs and in turn in the outer Revisi  onsschacht leads. The collector pipe should be dimensioned this way be that it can be driven by people, at least 600 mm clear diameter.

With this drainage system, the task is also simultaneous to solve, to roughly localize existing leaks, to apply additional seals if necessary. They happen in the un ter number 6 of the claims described manner. Depending on the extent of the leaks, one could use another Fully offset strut below a new sealing bowl be put. If there are minor leaks, this is necessary thought a "sealing strip" with the help of a fully offset Short struts of appropriate extent under the 1st seal insert bowl.

The subsequent sealing work is simplified Mining - this is especially true in used soil layers ten - because they are under a defined, artificial roof be able to walk. The introduction of the further sealing full set seamlessly under the 1st sealing bowl leaves tightness, especially expect the "sealing strip".

The task of restoring contaminated sites is in the Bun Republic of Germany, but of course also worldwide Problem of vital importance to the living world and of huge, also financial expenses. It will an entire industry has to deal with it because It is to be expected that not only a large number of so-called Contaminated sites can be retrofitted with a new basic seal is secure. Also for modern basic seals from Prob lematerials will have to be re-sealed.

An embodiment of the invention is shown in the drawing provided and described in more detail below. It shows

Fig. 1 shows the floor plan of an approx. 250 m wide and approx. 500 m long rubbish tip, under which the sealing bowl provided as a retrofit base seal, which is in its position, is arranged. The base of the landfill is diagonally hatched from bottom left to top right, and the sealing bowl from bottom right to top left.

In the, previously explored, mainly for reasons of exploration  Dump section (section line B-B) is the drainage collector and installed at the level of the track base. In this mün the drainage inlet pipes, which are located in a lateral Ab stood from 5-10 m immediately below the face be installed from the longwall. You are in this drawing only in the area of the strut stand (section line A-A) posed.

The trough section can be dropped behind the strut (as shown in Figure 2). However, it can also make sense to keep them open, as assumed in Figure 1.

the direction of the strut is essentially fal lend. A reversal of the direction of stroke is also possible if there are important reasons to do so.

The drives of the face conveyor are in this case on the Aspiring above ground (about A) and will be expedient covered with hiking tents (not shown here).

The two revision chutes are located at the top of the picture te, which may be useful only after completing the Ab seal are manufactured.

Figure 2 shows the section in the area of the strut stand (section line AA) with a view of the upper edge of the picture of Figure 1 and section BB.

Section A-A shows that a landfill height of approx. 60 m above the daily surface. In the The drainage collecting pipeline is indicated in the trough section. A drainage inlet pipeline is not shown.

The middle words, which may be due to mining reasons have been drawn in here.

Section B-B is a longitudinal section. Here was assumed gone that the trough section after longwall passage and on bring the sealing offset is dropped. The drainage system tem, which is located under the sealing bowl and above insert the drainage collector into the outer inspection shaft det, was not shown for reasons of scale.

The outer inspection shaft ends below the sealing nozzle sel, the inner inspection shaft extends to the deepest Point of the sealing bowl.

If the trough section is kept open (in whole or in part) the revision tasks were solved differently.  

Figure 3 is the floor plan of a sealing bowl in which leaks were located using the drainage system. It is believed that the bowl section existing from the manufacture of the sealing bowl was still open. With the help of accompanying sections, a full offset short strut of approx. 50 m in length was developed directly below the existing sealing bowl (left to right in the picture) in order to place a "sealing strip" under the leaks. In the absence of the trough stretch, the short strut can. U. can also be guided in a descending manner (in the picture from right to left).

Techni to be used in the manufacture of the short strut ks and operations essentially correspond to those which was already described in the manufacture of the sealing bowl were.

Claims (6)

1. Securing method for contaminated sites in the form of a slanted sealing bowl, which is subsequently manufactured as a basic seal under an contaminated site, characterized in that the basic seal is developed from a mined trough strut - double-winged or continuous, depending on the length of the required strut front. 2. Protection procedure for contaminated sites according to claim 1, characterized in that the mined Mul denstreb with full offset in a regular thickness to Ab gasket is filled and that this offset from a ge own building material, the introduction of which either known mining type or with other methods. 3. Protection procedure for contaminated sites according to claim 1, characterized in that the introduced sealing full offset evenly - i.e. without edges - is brought in Avoid punching effects. 4. Protection procedure for contaminated sites according to claim 1, characterized in that at the lowest point of the sealing bowl with the help of an inspection shaft (inner inspection shaft) o. Ä. there is a control option for pollutants and where these or water inflows can be disposed of To prevent overflow into the ground water. 5. Protection method for contaminated sites according to claim 1, characterized in that under the sealing bowl a con trollable drainage is made which is in the trough strut is continuously introduced under the full offset and the also in a revision shaft (outer revision shaft) or the like opens at the lowest point of the drainage system and with whose help checks the impermeability of the seal can be. 6. Protection method for contaminated sites according to claim 1, characterized in that depending on the location and extent nevertheless leaks occurred a possibility of re-sealing for the first sealing bowl, either again in the form another sealing bowl underneath or by manufacturing a "sealing strip" with the help of a so-called short strut.