DE2327851A1 - PROCESS AND DEVICE FOR STRENGTHENING THE ROCK OF A MOUNTAIN ASSOCIATION, IN PARTICULAR IN MINING PITS OF THE UNDERGROUND CONSTRUCTION - Google Patents

Description

DR.-ING. BY KREISLER DR.-ING. BEAUTIFUL FOREST DR.-ING. TH. MEYER DR. FUES DIPL-CHEM. ALEK VON KREISLER DIPL.-CHEM. CAROLA KELLER DR.-ING. KLDPSCH DIPL-ING. SELTING

COLOGNE.DEICHMANNHAUS

May 30, 1973 Sch-DB / ls

EXCHEM HOLDINGS LIMITED

31-35 Wilson Street, London EC2M 2UA, England

Method and device for reinforcing the rock of a mountain range, in particular in Underground mining pits

The invention relates to the reinforcement of rock and proposes a method for stabilizing or Solidification of weak rock formations, such as those found in mining pits. aside from that a reinforcement insert is specified for carrying out the method.

It is known to use relatively short rock steel bolts, essentially 1.5 to 2.1 m long, around underground openings to be arranged in order to stabilize the rock layer in the immediate vicinity of the openings and to stiffen. Such rock logs are in the rock by expandable shields or by wedge arrangements anchored or they are fixed at their inner end by quick-setting adhesive, the generally on an unsaturated polyester resin based. Such rock bolts at the ends are tensioned by a nut which is pressed against the

309851 / 0Λ21 _ ₂ _

stone surface around the one containing the rock bolt Borehole acts. The tension within a bolt tightened in this way imparts a force which broke the separation of the rock layer or the relative movement of adjacent blocks Rock inhibits and therefore the use of such bolts at reasonable intervals can create a stress zone of stiffening around a mine passage or other Create openings underground.

In another known reinforcement, the procedure is that the reinforcement insert, for example a bolt made of metal, wood or reinforced plastic, over its entire length in an extra for this drilled borehole is glued, with a known per se suitable resin or cement adhesive mixture is used. Such reinforcement elements are not tensioned, but they mediate due to their intimate connection with the rock, maximum local stiffening forces around any boundary surfaces, at which tensile and compressive forces cause disturbances that turn out to be an interruption of the original Express the connection between the rock formations. The adhesive mixture for such reinforcement elements can before the reinforcement element is pumped into the borehole or it is in one or more fragile capsules introduced into the borehole, which are then broken and their Content is activated by rotating the reinforcement element when it is introduced into the borehole. In in practice, the length is due to the limited space that is normally found in mine shafts

of the reinforcement element limited to 1.8 to 2.4 m, although under special circumstances bolts up to about 6 m in length around pit openings underground have been attached.

The relatively narrow rock layer that is associated with the conventional ones described. Reinforcement elements can be stiffened, is usually in the narrower area around a pit or a Mine section, however, requires much greater depth of temporary reinforcement to avoid fault zones to stiffen on long-front coal layers. In practice it is desirable to be about 15 to 30 m of the to be mined deposit and the immediately adjoining roof layer to the front to strengthen a to achieve optimal stabilization. An effective reinforcement to the front down to these depths has been made so far achieved by interconnected wooden bolts with a diameter of 36 mm that are in them adapted boreholes were used. In the applied technique of pumping in resin glue over the outer surface of the previously inserted bolt from the open end of the borehole, it is necessary to to provide a pipe or a hose to vent the bottom of the borehole, so that the adhesive the entire Fills the annular space between the bolt and the rock free of air inclusions. To bolts with a diameter of 36 mm and a ventilation pipe at least 15 m deep into a borehole in shallow, disturbed rock the borehole have a diameter of at least 50 mm, preferably 60 mm. The drilling such a borehole brings numerous difficulties

309851/0421 - 4 -

and it also requires the consumption of relatively large amounts of resin adhesive in order to produce the large Fill the annular space between the bolt and the borehole wall. There are also special drilling jigs required because the standard fixtures for making normal blast holes in mining pits are just holes with a diameter of about 43 mm to drill in the Location are.

The object of the invention is to provide a method for strengthening the rock of a mountain range, e.g. Long-front coal layers to be created in underground mining using conventional blasthole drilling machines permitted and in which the drilling of boreholes of relatively large diameter of the order of magnitude of 50 mm and more is not required.

This object is achieved in that one drills a borehole in the rock that at least in the borehole a tubular element is introduced, which consists of several longitudinal there is sleeve-like assembled ring segments that are offset from one another in the longitudinal direction a coaxially arranged inner tube are attached, that one continues the introduction of the tubular element until its inner end rests against the bottom of the borehole and its outer end protrudes into the borehole mouth, that an adhesive mass is introduced from the outside through the inner tube of the tubular element into the borehole for so long until the adhesive mass on the inner end of the pipe element flows out and has flowed back through the annular space between tubular element and borehole wall, wherein the Adhesive feed is continued until the ring

308851/0421

space is essentially filled with the adhesive mass, and that you then cure the adhesive mass can, .so that the reinforcing insert formed by the pipe element connects with the rock.

The reinforcing insert expediently has a plurality of tubular elements arranged one behind the other, each of which are formed from a plurality of longitudinally directed ring segments which are offset from one another in the longitudinal direction are attached to a coaxial inner tube. The inner tubes of successive tube elements can thereby a connecting link may be interconnected which holds the end portions of successive tubular elements together .

In a further embodiment of the invention, the reinforcement insert be formed from a continuous uninterrupted inner tube on which several longitudinal Ring segments are attached offset from one another in the longitudinal direction.

The ring segments of the tubular elements forming the reinforcement insert can be made of any suitable material, e.g. wood, metal, synthetic thermoplastics or thermosetting materials, asbestos cement or resin-bonded Glass fibers are made, while the inner tube is made of synthetic plastic such as e.g. Polyethylene can be made.

The ring segments of the tubular elements preferably have a semi-cylindrical cross section. However, you can if necessary also show other cross-sectional shapes.

309851/0421 - 6 -

As a connecting link for fastening several strung together in the sense of the first embodiment Pipe elements can be used, for example, a pipe sleeve into which the pipe elements are inserted appropriately or a pin part protruding from the inner tube at one end of a tube element can be provided be, which can be inserted into one end of the inner tube of the following tubular element like a plug.

In order to reduce the risk that the inner end of the reinforcement insert during the introduction into the borehole is blocked by drilling dust residues, it is advisable to cover the inner end of the reinforcement insert with a to equip tubular, openwork jacking head with a closed front end. The jacking head has a substantially cylindrical body which tapers towards the closed front end is to facilitate the introduction of the reinforcement insert into uneven drilled holes. aside from that if the propulsion head has several outlet openings on its outer surface, through which the adhesive mass emerges into the annular space surrounding the reinforcement insert in the borehole. The breakthroughs are advantageously arranged distributed essentially symmetrically over the body of the propulsion head.

30S851 / 0421

The invention is explained in more detail with the aid of drawn examples. Show it;

Figure 1 is a view of the end portion of a tubular member from which an embodiment of a reinforcement is made can be,

Fig. 2 is a partial longitudinal section of a second embodiment

form of a reinforcement and

3 shows a view of a propulsion head for a reinforcement arrangement.

According to Fig. 1, a tubular element, which with many Gleichgestäfceten Elements for producing a reinforcement according to the method according to the invention are used, two longitudinal ones Ring segments 2 semi-cylindrical shape, which are offset from one another on a coaxially pre-arranged

see inner tube 1 are attached. ·

Fig. 2 shows a preferred reinforcement, consisting of a continuous inner tube 1, which of many is surrounded by semi-cylindrical ring segments 2, which are arranged offset from one another on the tube 1, so that at least half of the tensile strength of the reinforcement arrangement is present at each point. In the In practice, the inner tube 1 can be made of flexible or semi-rigid plastic material or of metal, for example and can consist of a coil in an uninterruptible Length to be introduced into the borehole. The semi-cylindrical ring segments 2 can be in matching Lengths, e.g. 1 to 2 m, can be provided and they can

be attached to the tube 1 for example by means of adhesive tape or metal or plastic clips.

Fig. 3 shows a propulsion head with the reinforcement 1 or 2 can be connected. The propulsion head has a tubular body 1, which is tapered has conical closed front end 2. Several openings 3 are essentially symmetrical Distributed over the surface of the tubular body 1.

An adhesive or preferably a resin mixture can be used as the adhesive composition for the process according to the invention can be used, which is advantageously based on an unsaturated polyester resin.

The following examples provide a further insight into embodiments of the invention.

example 1

For the production of pipe elements according to Fig. 1, the inner pipe 1 was made of highly compressed polyethylene pipe with an inner diameter of 16 mm and an outer diameter of 19 mm, while the ring segments 2 were made of semicircular ring sections of wooden strips made of kerning wood with an inner diameter of 19 mm and a Outside diameters of J> 6 mm were formed. The plastic pipe and wooden strips were cut into 167.64 cm long pieces and then joined together with a longitudinal offset such that the total length of the finished pipe element was 182.8 cm, with each end of the inner pipe in the middle

- 9 -309851/0421

the respective ends of two semicircular wooden Ring segments came to rest. It became a quick-setting adhesive based on unsaturated polyester resin used to connect the inner tube with the ring segments to form the tube element. To a The end of the tubular element then became an 8 "long High density polyethylene pipe with an inner diameter of 36 mm and a wall thickness of 0.5 mm pushed on, which was taped so that one inch of the Polyethylene pipe over one end of the pipe element protrude, whereby a connecting member for connecting another pipe element is formed.

A horizontal borehole of 43 mm was made in a fault location on a long-front coal layer Diameter and 13.4 m length. Then the tubular element described with a tapered Propeller head according to Fig. 3 equipped. This jacking head had a diameter of 36 mm and a length of 300 mm and was with sixteen perforations of sow each 10 mm in diameter, which were distributed approximately regularly over its surface. The pipe element with the attached jacking head was inserted into the borehole and another similar tubular element was passed through Insertion into the open end of the 36 mm wide connecting link connected. A further six corresponding pipe elements were joined together in a similar manner until the jacking head had reached the inner end of the borehole. The plastic connectors were then removed from the end of the last pipe element, which is now with a Reinforcement of the equipped borehole.

309.851 / 0421

A supply line from a manually operated diaphragm pump was connected to the outer end of the plastic inner pipe of the reinforcement insert and binding agent based on unsaturated polyester resin was pumped through the reinforcement to the bottom of the borehole. The binder flowed through the jacking head and back along the annular space between the reinforcement insert and the borehole wall. Pumping was stopped when the resin binder appeared in the annulus at the well mouth. The resin-based binder contained in addition to unsaturated polyester resin 50 wt -.% Inert-puller and 1 part by weight of pyrogenic silica and J ^ was activated by a benzoyl peroxide / amine Beschieunigersystem known type.

A number of slot reinforcement inserts were as described with intervals of about 1 m over the entire Disturbance zone of the coal layer attached. After the pumped-in resin binder hardened, the carbon became with conventional mining machines and were obtained through the stabilizing effect of the reinforcement inserts very significant improvements in soil conditions were noted.

Example 2

There were coils of high density polyurethane pipe with an inside diameter of 16 mm and an outside diameter of 19 mm in lengths of 13 * 71 m.

Semicircular wooden ring segments with an inside diameter of 19 mm and an outside diameter of 36 mm were trimmed from kerning wood.

309851/0421

- 11

A borehole with a diameter of 43 mm and a length of 13 * ^ 1 m was drilled into the broken rock roof near a long-front coal layer. One of the semicircular wooden ring segments 182 cm long and another 91 cm long segment were joined together near the end of one of the polyethylene tubing coils. Then the connection end was equipped with a jacking head according to FIG. 3 and. _# Inserted 91.4 cm into the borehole, leaving 91.4 cm of one of the wooden ring sections protruding from the borehole. Then a 182 cm long semicircular wooden ring segment was attached and the joint pieces were driven a further 91 * ^ cm into the borehole. Similar wood ring segments were set up one after the other, with each attachment being followed by a 91.4 cm (91.4 cm) feed until the jacking head reached the bottom of the borehole. The protruding parts of the wooden segments were sawed off so that the drill hole contained a reinforcement insert as shown in FIG. The outer end of the continuous polyethylene inner tube was then connected to the feed line of a diaphragm pump, as described for Example 1. A resin-based binder was pumped through the inner tube and expelled against the inner end of the wellbore until it emerged in the annulus at the wellbore mouth. In the broken roof over a hollow seam, a pattern of reinforcement inserts of the type described was introduced and the entire arrangement was responsible for the fact that the roof conditions were significantly improved when the coal seam was mined.

309851/0421

Claims (12)

Expectations 1.Process for strengthening the rock of a mountain group, especially in mine pits of underground construction, characterized, that one drills a borehole in the rock, that at least one tubular element is introduced into the borehole which consists of several longitudinally aligned, sleeve-like ring segments, which are attached to each other offset in the longitudinal direction on a coaxially arranged inner tube that the introduction of the tubular element is continued until its inner end rests against the bottom of the borehole and its outer end protrudes into the borehole mouth that from the outside an adhesive mass through the Inner tube of the tubular element is inserted into the borehole until the adhesive mass on the inner The end of the pipe element flows out and flowed back through the annular space between the pipe element and the borehole wall is, the adhesive supply is continued until the annulus is substantially with the adhesive mass is filled, and that you can then cure the adhesive mass, so that connects the reinforcement insert formed by the pipe element to the rock. 2. The method according to claim 1, characterized in that the each in the borehole Introduced pipe element each time a further pipe element is added as an extension we d. - 13 - 309851/0421 3 · The method according to claim 1 " characterized in that. that on the one-piece length of the inner pipe advancing into the borehole, ring segments that are offset from one another in the longitudinal direction are fastened one after the other, 4. The method according to claims 1 to 3 _£ characterized in that an adhesive mixture based on resin is used as the adhesive mass a ο Method according to claim k _s characterized in that a mixture based on unsaturated polyester resin is used as the adhesive mass. _{fl fl} in ο reinforcing insert for use in carrying out the process according to claims 1 to 5, characterized that in each case at least one tubular element ISTJ present, dag, having a plurality of longitudinal Ringsegmenie (2) ,, the manner of a sleeve-assembled and longitudinally offset from one another in a coaxial Inner tube (1) are attached » 7 »Reinforcement insert according to claim 6, characterized in that each reinforcement insert has several tubular elements arranged one behind the other, and that the inner tubes (1) of successive tubular elements are connected to one another via a connecting member which connects the end parts of successive tubular elements. 309851 / holds. 8. Reinforcement insert according to claim 7 * thereby characterized in that a plug-in sleeve is used as the connecting member. 9 Reinforcement insert according to Claim 6, characterized in that the inner tube (1) is designed continuously uninterrupted over the entire length of the reinforcing insert, and that the it as a substantially closed sleeve surrounding ring segments (2) in the longitudinal direction to each other are attached offset " 10. Reinforcement insert according to claims 6 to IQ, characterized in that the ring segment (2) have a semi-cylindrical cross section. 11. Reinforcement insert according to claims β to 9 _3, characterized in that its inner end is provided with a tubular _p on its outer surface with multiple perforated propulsion head (1) with a closed front end (2). 12. Reinforcing insert according to claim 11, characterized characterized in that the propulsion head consists of a substantially hollow cylindrical The body is gebildi, which tapers towards the closed front end (2). 309851/0421 ~ ¹⁵ " Γ3. Reinforcement insert according to claim 11 or 12, characterized in that the openings (J) in the lateral surface of the Propulsion head (1) are arranged distributed essentially symmetrically. Blank page