GB1572653A - Arched roof support structure for use in mine and tunnel construction - Google Patents

Description

(54) AN ARCHED ROOF SUPPORT STRUCTURE FOR USE IN MINE AND TUNNEL CONSTRUCTION (71) We, BERGBAUSTAHL GmbH & BR< CO.. a German Body Corporate, of 48 Elberfelder Strasse. 58()() Haven Westfalia.

Germany. do hereby declare the invention for which we pray that a patent may be granted to us, and the method by which it is to be performed to be particularly described in and by the following statement: The invention relates to an arched roof support structure for use in mine and tunnel construction.

The invention relates to arched roof support structures of the kind comprising two ridge segments together forming an upper arch-shaped portion of the support structure. and two lower segments each connected to one of the ridge segments respectively, for sliding movement therealong, by an upper clamping connection connecting the upper end of the lower segment to the ridge segment and a lower clamping connection connecting the lower end of the ridge segment to the lower segment.

Pre-assemblv of such roof support structures, which can take place at a predetermined distance behind the tunnel face, is a means of rationalization for shortening the time of final erection of the roof support structures at the tunnel face. Pre-assembled structures are transported from the preassembly site into position at the tunnel face by means of operators. movable platforms or with the help of suspended trolley tracks and. for this reason, the pre-assembled structures must be smaller overall dimensions than the structures already in position lining the tunnel.

In a roof support structure according to the invention, not only are the ridge segments alreadv assembled. but the entire structure. including the lower segments, is pre-assembled in order to achieve a high degree of rationalisation.

For the final erection. the clamping connections are loosened so that the lower segments can slide along the ridge segments.

These connections may be so designed that at final erection they are replaced by different clamping connections which hold together the overlapping segments of the finished structure. Such an arrangement may have, in certain circumstances, the advantage that the lower segments (which, when erected. normally lie beneath the ridge segments) can be pre-assembled alongside the ridge segments, thus saving space in height during transport to the tunnel face. Preferably, however, clamping connections are used for pre-assembly which can also be used as the final clamping connections for the overlapping segments, after the final erection of the roof support structure. In this case the lower segments are supported below the single or two-piece ridge segments during pre-assembly. A higher degree of rationalization will still, however, be achieved.

In structures of the kind first mentioned above, it is necessary to retain the clamping connections in such a manner that they cannot slide off the segments when the lower segments are slid along the ridge segments for final erection. The retention must be such as to permit the tightening or loosening of the connections without the retention becoming ineffective.

A known device for the purpose consists in providing lateral recesses in the ends of the ridge segments through which bolts can be inserted. From these bolts, the lower ends of the lower segments are slung by means of a chain. In order to avoid the sliding-off of the upper connections, these connections are provided with a special stirrup which rests on the ridge segment and special clamping devices for the lower segments. The provision of recesses, irrespective of the manner in which such recesses are produced is, from the point of view of tunnel support technology. extremely unfavourable. On the one hand. the recesses weaken the segments in those parts of their cross-section where they are particularly stressed. On the other hand, the provision of the recesses is most undesirable with modern gallery lingins.

It is also undesirable that the upper clamping connections should require special tightening devices. On the one hand, the mechanical elements necessary for this are complicated and are subjected. in the conditions prevailing below ground, to considerble wear and tear. On the other hand, the correct application of such tightening devices below ground is hard to control.

Mistakes can lead to considerable endangering of machines and men present below the suspended structures as they are transported along the tunnel.

The basic task of the invention is to prevent the weakening of the roof support and to simplfy the attachment of the clamping connections and make them more secure.

This task is solved according to the invention in that, in an arched roof support structure of the kind first referred to, each upper clamping connection engages lugs on the lower segment from below and the lower clamping connection engages lugs on the ridge segment from above.

The attachment of the lugs is relatively easv because the finish of the segments is not critical. Because of this. welding can be considered as this is limited to verv small areas of the lining profile on account of the low forces and loads to be transferred by the lugs. On the other hand, the lugs have the advantage that they produce a strong connection. The lugs provided on the upper ends of the lower segments in fact act as driving dogs to urge the upper clamping connections downwards. while the lugs fixed to the lower ends of the ridge segments retain the lower clamping connections in position as the lower segments slide. In both cases. the effectiveness of the lugs does not depend. or onlv to a slight degree. on the care with which the connections, in other respects, are tightened.

On the one hand. the invention has advantages from the point of view of manufacture because the fixing of the lugs can easily be incorporated in the manufacturing programme of the roof support structures.

On the other hand. they lead below ground to considerable simplications. not only in materials but also in labour expenditure and in the assuring of adequate safety.

Preferablv the lugs are attached to the outer sides of the segments. They can be fixed here with particular ease and their presence can be checked at any time.

Each of said segments may be generally U-shaped in cross-section with flanges at the ends of the arms of the U. and in this case the lugs may be attached to said flanges.

The flanges are relatively thick parts of the structure and for this reason are better suited for the attaching of the lugs than the thinner parts, Besides, care must be taken that the lugs are as simple as possible. This is ensured in an embodiment of the invention in that they consist of sections of rectangular section bar which are welded by their ends to the segments.

The invention is explained more fully in the following description of a preferred embodiment thereof, reference being made to the accompanying drawings, in which: Figure 1 is a diagrammatic cross-section through a tunnel showing an erected roof support structure and a pre-assembled support structure before final erection; Figure 2 shows the lower end of one of the ridge segments in an enlarged illustration, and shows the clamping connection fitted there; Figure 3 shows the upper end of a lower segment corresponding to the illustration in Figure 2; Figure 4 is an end view of a segment furnished with lugs.

Figure 5 is a side elevation of a part of the segment in Figure 4; and Figure 6 is a plan view of the part of the segment shown in Figures 4 and 5; In Figure 1, the floor of the tunnel is indicated at 1. At 2 there is shown in dotted lines the profile of a section cutting machine in order to make clear to what extent the pre-assembled roof support structure has to be reduced in size in order to get it to the position where it is to be finally erected. The appearance of the final tunnel lining can be seen from the erected roof support indicated generally at 3. The roof support 3 comprises lower segments 4 and 5 whose lower portions are essentially straight and lead upwardly to inwardly curved portions. The top of the roof support structure is generally indicated at 6 and consists of two curved ridge segments 7 and 8 respectively, which overlap at 9. This design of the top of the roof support is not, however, an essential feature of the invention. It is also conceivable to produce the top of the roof support from a single continuous ridge segment.

As best seen in Figure 4, each segment of the roof support is of generally U-shaped cross-section. the arms 43 and 44 of the U terminating in flanges 45 and 46 respectively.

The lower segments 4 and 5 overlap with the ridge segments 7 and 8 at 10 and 11 respectively, the segments being nested where they overlap. At each overlap 10 or 11 clamping connections 13 and 14 are located. Side views of the clamping connections 13 and 14 are shown in Figure 3 and Figure 2 respectively, although in those figures the parts are shown in their condition when the roof support structure is pre-assembled for transport but before it is fully erected. At overlap 9 between the ridge segments 7 and 8, clamping connections similar to the clamping connections 13 and 14 are provided.

The clamping connection 13, as shown in Figure 3. comprises a lower shackle 15 which straddles the underside of the lower segment (4 in Figure 3) and has flanges 16.

The flanges 16 are formed with holes through which pass the lower threaded ends of bolt hooks 17. Clamping nuts are screwed on to the threaded ends of the bolt hooks.

The heads 18 of the bolt hooks 17 rest on the flanges of the ridge segment (7 in Figure 3).

On the shackle 15 are lugs 19 which rest against the end face 20 of the upper end of the lower segment 4. The shanks of the bolt hooks 17 engage lugs 39 formed on the flanges of the thrust segment in a manner to be described.

The clamping connection 14 for the lower part of the overlap is shown in Figure 2 and comprises a shackle 21 which straddles the underside of the lower segment (5 in Figure 2) and has flanges 22. The flanges 22 are formed with holes through which pass the threaded ends of bolt hooks 23. Clamping nuts are screwed on to the threaded ends of the bolt hooks. The heads 24 of the bolt hooks 23 rest on the flanges of the ridge segment (S in Figure 2). The two bolt hooks 23 are held together by a component 26 which is formed with a lug 27 engaging the lower end face 28 of the ridge section (8 in Figure 2). The shanks of the bolt hooks 23 engage lugs 40 formed on the flanges of the ridge segment in a manner to be described.

The two clamping connections 13. 14 are so formed that on sliding each lower segment. 4 or 5. relatively to its associated ridge segment. 7 or 8. the upper connection 13 moves with the lower segment and the lower connection 14 moves with the ridge segment.

Figure 1 illustrates. at 30. a roof support structure which is pre-assembled ready for final erection. The two ridge segments 31 and 32 overlap at 33 and are clamped together bv clamping connections (not shown) similar to the connections 13 and 14.

The two lower segments 34 and 35 of the roof support 3( are. on the other hand, first hung under the ridge segments 31 and 32 respectively as shown in Figure 1. For this purpose the upper end 36 of each lower segment 34 or 35 is supported on the respective ridge segment 31 or 32 by the clamping connection 13 and the lower end 37 of each lower segment is supported on the lower end 38 of the respective ridge segment 31 or 32 by the clamping connection 14.

At the upper end 36 of each lower segment 4, 5 34 or 35 are the lugs 39 referred to earlier, and the corresponding lugs 40 are attached to the lower ends 37 of the ridge segments 7 8, 31 or 32. As can be seen from Figure 2 and Figure 3, the upper clamping connections are now resting with sides which face the upper ends of the lower segments engaging the lugs 39 on the lower segments ie the upper clamping connections engage the lugs from below. According to the illustrated embodiment, it is the shanks of the hook bolt 17 which engage the lugs.

Also the lower clamping connections, i.e.

the connections shown in Figure 2, are resting with their side which faces the lower end of the ridge segment 8 engaging the lugs 40 of the ridge segments 8 ie the lower damping connections engage the lugs from above. Again, it is the shanks of the hook bolts 23 which engage the lugs 40.

Figures 4 to 6 show the formation of the lugs in detail. As previously described each segment of the roof support structure is of U-shaped cross-section having arms 43 and 44 which feature flanges 45 and 46 respectively on their free ends. On the outer sides 47 of the flange 45 and 46, lugs 40 and 41 respectively are fixed. The two lugs are formed in the same manner so that it suffices to describe one of these lugs in detail.

As the end elevation in Figure 4 and the plan in Figure 6 show, the lugs are formed from iron bar portions 50 having a generally rectangular cross-section. These portions of iron bar are welded to the respective side of the segment flange by means of a circumferential fillet weld.

These weld seams may measure Smm with a segment weight of 36 kg/m. The width of the iron bar portions can amount to 19mm and their heights to 24mm.

WHAT WE CLAIM IS: 1. An arched roof support structure, for use in mine and tunnel construction, comprising two ridge segments together forming an upper arch-shaped portion of the support structure, and two lower segments each connected to one of the ridge segments respectively, for sliding movement therealong, by an upper clamping connection connecting the upper end of the lower segment to the ridge segment and a lower clamping connection connecting the lower end of the ridge segment to the lower segment, the upper clamping connection engaging lugs on the lower segment from below, and the lower clamping connection engaging lugs on the ridge segment from above.

2. An arched roof support structure

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (5)

**WARNING** start of CLMS field may overlap end of DESC **. located. Side views of the clamping connections 13 and 14 are shown in Figure 3 and Figure 2 respectively, although in those figures the parts are shown in their condition when the roof support structure is pre-assembled for transport but before it is fully erected. At overlap 9 between the ridge segments 7 and 8, clamping connections similar to the clamping connections 13 and 14 are provided. The clamping connection 13, as shown in Figure 3. comprises a lower shackle 15 which straddles the underside of the lower segment (4 in Figure 3) and has flanges 16. The flanges 16 are formed with holes through which pass the lower threaded ends of bolt hooks 17. Clamping nuts are screwed on to the threaded ends of the bolt hooks. The heads 18 of the bolt hooks 17 rest on the flanges of the ridge segment (7 in Figure 3). On the shackle 15 are lugs 19 which rest against the end face 20 of the upper end of the lower segment 4. The shanks of the bolt hooks 17 engage lugs 39 formed on the flanges of the thrust segment in a manner to be described. The clamping connection 14 for the lower part of the overlap is shown in Figure 2 and comprises a shackle 21 which straddles the underside of the lower segment (5 in Figure 2) and has flanges 22. The flanges 22 are formed with holes through which pass the threaded ends of bolt hooks 23. Clamping nuts are screwed on to the threaded ends of the bolt hooks. The heads 24 of the bolt hooks 23 rest on the flanges of the ridge segment (S in Figure 2). The two bolt hooks 23 are held together by a component 26 which is formed with a lug 27 engaging the lower end face 28 of the ridge section (8 in Figure 2). The shanks of the bolt hooks 23 engage lugs 40 formed on the flanges of the ridge segment in a manner to be described. The two clamping connections 13. 14 are so formed that on sliding each lower segment. 4 or 5. relatively to its associated ridge segment. 7 or 8. the upper connection 13 moves with the lower segment and the lower connection 14 moves with the ridge segment. Figure 1 illustrates. at 30. a roof support structure which is pre-assembled ready for final erection. The two ridge segments 31 and 32 overlap at 33 and are clamped together bv clamping connections (not shown) similar to the connections 13 and 14. The two lower segments 34 and 35 of the roof support 3( are. on the other hand, first hung under the ridge segments 31 and 32 respectively as shown in Figure 1. For this purpose the upper end 36 of each lower segment 34 or 35 is supported on the respective ridge segment 31 or 32 by the clamping connection 13 and the lower end 37 of each lower segment is supported on the lower end 38 of the respective ridge segment 31 or 32 by the clamping connection 14. At the upper end 36 of each lower segment 4, 5 34 or 35 are the lugs 39 referred to earlier, and the corresponding lugs 40 are attached to the lower ends 37 of the ridge segments 7 8, 31 or 32. As can be seen from Figure 2 and Figure 3, the upper clamping connections are now resting with sides which face the upper ends of the lower segments engaging the lugs 39 on the lower segments ie the upper clamping connections engage the lugs from below. According to the illustrated embodiment, it is the shanks of the hook bolt 17 which engage the lugs. Also the lower clamping connections, i.e. the connections shown in Figure 2, are resting with their side which faces the lower end of the ridge segment 8 engaging the lugs 40 of the ridge segments 8 ie the lower damping connections engage the lugs from above. Again, it is the shanks of the hook bolts 23 which engage the lugs 40. Figures 4 to 6 show the formation of the lugs in detail. As previously described each segment of the roof support structure is of U-shaped cross-section having arms 43 and 44 which feature flanges 45 and 46 respectively on their free ends. On the outer sides 47 of the flange 45 and 46, lugs 40 and 41 respectively are fixed. The two lugs are formed in the same manner so that it suffices to describe one of these lugs in detail. As the end elevation in Figure 4 and the plan in Figure 6 show, the lugs are formed from iron bar portions 50 having a generally rectangular cross-section. These portions of iron bar are welded to the respective side of the segment flange by means of a circumferential fillet weld. These weld seams may measure Smm with a segment weight of 36 kg/m. The width of the iron bar portions can amount to 19mm and their heights to 24mm. WHAT WE CLAIM IS:

1. An arched roof support structure, for use in mine and tunnel construction, comprising two ridge segments together forming an upper arch-shaped portion of the support structure, and two lower segments each connected to one of the ridge segments respectively, for sliding movement therealong, by an upper clamping connection connecting the upper end of the lower segment to the ridge segment and a lower clamping connection connecting the lower end of the ridge segment to the lower segment, the upper clamping connection engaging lugs on the lower segment from below, and the lower clamping connection engaging lugs on the ridge segment from above.

2. An arched roof support structure

according to claim 1, wherein said lugs are attached to the outer sides of the segments.

3. An arched roof support structure according to claim 1 or claim 2, wherein each of said segments is generally U-shaped in cross-section with flanges at the ends of the arms of the U. and wherein said lugs are attached to said flanges.

4. An arched roof support structure according to any of claims 1 to 3, wherein each lug comprises a section of iron bar welded to a segment.

5. An arched roof support structure substantially as hereinbefore described with reference to the accompanying drawings.