Polygon expansion

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1: 1 model of an open polygon construction

The polygon construction , also known as knee construction , is a composite polygonal construction that is built into mining sections and rock sections to reinforce the section construction . Due to its high load-bearing strength , combined with great elasticity, this type of extension is also well suited for high- pressure routes. Polygon lining is made of wood or steel .

Timber construction

In the case of polygon construction made of wood, a distinction is made between open and closed polygon construction. The open polygon expansion consists of a cap and four pit punches that support the cap. These four stamps are installed in such a way that there is a foot stamp and a head stamp on each side. The stamps are connected to one another via a round piece of wood, the so-called runner. In another type of open polygon construction, a continuous single stamp is placed on one joint side ; this construction is referred to as half polygon construction. A distortion is introduced over the cap either from half-timber or, in the case of larger cavities, from round timber. The closed polygon expansion is an extension of the open polygon expansion. Here a sole spreader is introduced or, depending on the size of the route, additional combinations of stamps and runners are installed. The production of the wooden polygon extension is very labor-intensive.

Steel construction

In the case of polygon construction made of steel, thicker profiles are usually used than in the usual route construction. Wooden stamps or steel profile supports are used as supports for the expansion. Wooden or recovery boxes or walls are not suitable as a support due to their dimensions. The individual segments are connected either by steel joints or by joint sockets with wooden runners. Joint shells made of wood are used if wooden stamps are used as a support. A disadvantage in particular in wood runners in the ridges is, the hinge shells of the arc segments at that destruction by pushing on the rotor. This can also happen if the shock pressure is too high. In both cases, the affected arch segments must be spread apart. If the complete polygon structure is made of steel, steel joints are used on all connections. In this version, a good bolt is introduced to secure the individual structures . If there is no or insufficient bolting, the support arches tilt and the polygon support loses its load-bearing capacity considerably. The joints must be placed directly on the standing mountain . If this is not possible, a full request must be achieved by backfilling .

The steel polygonal structure normally has five joints. Three joints are located above the sole of the track, the other two joints form the contact surfaces of the lower punch with the person lying down . There is also a polygon construction with six joints for long stretches. The structure is similar to the polygon structure with five joints, but with the polygon structure with six joints in the roof area, two rows of runners are installed. The two rows of runners are one to one and a half meters apart and run parallel to each other. There are also open and closed polygons for steel polygons. The closed polygon expansion is created by inserting a flat sole arch. The closed polygonal expansion is used when the sole is swelling. It has two advantages over ring expansion . First of all, a smaller opening in the sole area is required for the installation of the polygon lining than for the ring lining. The reason for this is the only slightly curved sole segment of the closed polygonal structure. In addition, the closed polygon expansion has a certain flexibility that the ring expansion does not have due to its design.

Individual evidence

  1. ^ Walter Bischoff , Heinz Bramann, Westfälische Berggewerkschaftskasse Bochum: The small mining dictionary . 7th edition, Verlag Glückauf GmbH, Essen 1988, ISBN 3-7739-0501-7
  2. ↑ Nieß: route safety and relief slashing in pressurized seams . In: Glückauf, Berg- und Hüttenmännische magazine. Association for Mining Interests in the Upper Mining District Dortmund (Ed.), No. 27, Volume 45, July 3, 1909, pp. 953–959.
  3. ^ Tilo Cramm, Joachim Huske: Miners' language in the Ruhr area. 5th revised and redesigned edition, Regio-Verlag, Werne 2002, ISBN 3-929158-14-0 .
  4. ↑ Georg Leupol, Maja Hocker: Driver's Handbook. [1] (accessed on January 9, 2012; PDF; 11.8 MB).
  5. ^ Carl Hellmut Fritzsche: Textbook of mining science. Second volume, 10th edition, Springer Verlag, Berlin / Göttingen / Heidelberg 1962

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