Hydraulic and earth engineering – Earth treatment or control – Shoring – bracing – or cave-in prevention
Patent
1992-01-13
1993-08-31
Taylor, Dennis L.
Hydraulic and earth engineering
Earth treatment or control
Shoring, bracing, or cave-in prevention
405288, 405303, E21D 1522
Patent
active
052403548
DESCRIPTION:
BRIEF SUMMARY
The invention relates to a support element for use in underground mining or tunnel construction, in particular for securing mining cavities at the longwall face and headway, comprising inner and outer tubes which move inside each other and a building material core which may be hardened and which keeps the two tubes at a distance from each other, whereby the outer and inner tubes are constructed as a telescopic tube which is continuous on the inside and is closed at the end.
BACKGROUND OF THE INVENTION
The so-called single use support is still used at the present time in many areas of underground mining. It consists primarily of suitably sized wood props, trough profile supports, double-T supports, etc. Often individual hydraulic props are also used, either to supplement the latter or by themselves. This results, however, in great expenditures because of the high production costs. The required support pressure in these hydraulic systems may be maintained advantageously by the pressure in the hydraulic system (300 to 600 bar) and accurately operating pressure limit valves. All props in the system are characterized by identical characteristic lines. Such hydraulic systems represent the optimum technical solution for rock support in a mobile version. But in a stationary version the above mentioned disadvantages occur. In headways where convergence is expected, so-called flexible trough profiles are used, whereby the friction coefficient is inaccurate and thus a safe and even support of the ceiling or the roof cannot be ensured. This also applies to the two-part roadway or headway props known from German Patent 818 332 where the outer prop is filled with a compressible fill mass. The intention there is to achieve a specific flexibility of the otherwise rigid construction. But the disadvantage is that such elements are not tight enough for effective fill masses to be used. The used bitumen-like plastic fill masses however do not provide the necessary and required support pressures. The same is true for the solution known from German Offenlegungsschrift 32 36 421.0 in which such a pasty mass is arranged between two hollow tubes and is supposed to be displaced from there.
The invention thus has the task of creating a support element used as a single use prop which supports early on, absorbs high pressures, and is easy to handle.
SUMMARY OF THE INVENTION
According to the invention this task is solved in that the prop is composed of two or more outer and inner tubes which form a telescopic pipe which is continuous on the inside and closed off at the end, said tubes being constructed so that they may be mechanically braced in various extension lengths, that they have drainage bore holes distributed over their length, and that the filling consists of a building material core which may be hardened.
With such a construction it is first possible to advantageously brace the telescopic tube between roof and floor using simple mechanics. From the start the invented single use prop is thus able to introduce significant forces into the rock as soon as the building material is filled in and has hardened. In addition, it is advantageously anchored stably so that the filling with concrete or building material may take place safely. Since the building material is only filled in later, the single use prop is easy to use and is characterized also in that the concrete or building material may be pumped in a more liquid form since the excess water is drained and removed over the drainage device, i.e. the drainage boreholes. Because of this draining, the filled in building material forms a supporting building material core which is significantly stabilized by the surrounding steel tube and is shaped so that it is able to absorb high supporting forces far in excess of 100 tons and pressure forces. Since the building material core in both tube parts stands after hardening as a support column, the mechanics providing the preload then are no longer significant, so that here a simple and cheap mechanism may be used. The invented tele
REFERENCES:
patent: 3396545 (1968-08-01), Lamberton
patent: 3469358 (1969-09-01), Archer et al.
patent: 3891184 (1975-06-01), Fields
patent: 4255071 (1981-03-01), Koppers et al.
patent: 4332512 (1982-06-01), Heintzmann et al.
Creighton Wray James
Ingenieurtechnik GmbH & Co. KG
Taylor Dennis L.
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