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Abstract

Content

Introduction

Steady interest to a problem of fastening and maintenance of mine workings on coal mines last decades inseparably linked with increasing requirements to durability and reliability of applied constructions of supports in becoming complicated geological conditions of working of deposits, an intensification of rock pressure manifestations.

1. Actuality themes.

In the abstract experience of maintenance of development workings by various frame constructions of a support and a tendency of its development, including for the nearest period is analysed.

2.The review of researches and minings.

2.1 Review of the international sources.

With industrial development of metal rolling in 40th years of 19 centuries steel frame supports have started to be applied widely in practice of underground excavations of mines of Germany and Czechia. Originally in mine workings used rigid frames from steel double tee a profile or a rail connected by means of laths and bolts. However, considerable displacement of a pedigree contour led to inadmissible deformations of a support and necessity of its repair as the rigid construction can adapt to mixture of rocks only by residual deformation with the subsequent destruction of elements of a frame. Thereupon to the XX-th century beginning rigid metal constructions were considered unsuitable for fastening of mine workings. Therefore further perfection of steel frame supports went by the way of increase in their working capacity and the adaptation (adaptation) to form to change of section of a development. For this purpose at the first stage (till 1924) The additional hinges have been entered into a construction of a steel arch support, allowed to lower non-uniformity of distribution of external loadings at the expense of their transfer on rocks surrounding a support. The special merit on an intrusion of articulated arches belongs to firm «F.V.Mol and sons» thanks to which in 30-40th years of 20 centuries the steel frame support finds mass application on coal mines of Ruhr. At the second stage, in 1932 firm "Tissen-Hajntsman" (Germany) develops pair profiles of various standard sizes and a successful construction of their connections (a prototype of present locks of a pliability). Thanks to it the frame support became yielding and, having kept the functions, has had an opportunity to "leave" from a rock pressure without destruction, adapting to mixtures of a pedigree contour. After the Second World War metal yielding supports are widely adopted in the majority of the industrially-developed countries. By the end of 50th years of 20 centuries by a steel frame support it was maintained: in Germany - to 50 % of mine workings, in France - more than 60 %, in England - more than 70 %, in Belgium - to 90 %. Since 50th years of 20 centuries wide use of steel frame supports on mines of the former USSR has begun. The big contribution to mining of a steel frame support was brought by the domestic schools of thought which have arisen on the basis of mountain high schools and branch institutes.

Originally operations on designing and an intrusion of frame supports have been concentrated in DonUGI (Donetsk)[1]. Here special steels have been developed for manufacturing of elements of a support a parametrical number of interchangeable special profiles (ISP), standard materials on manufacturing and application of yielding supports of type АП (Commissioners of M. А, Ziegel F.S., etc.) are created.

The big contribution to mining of constructions of equally-radius supports providing maintenance of development workings in the conditions of inclined and abrupt falling on mines TSRD, have brought prof. S.J.Lipkovich and S.V.Krasnov.

Important researches on analysis of interaction of a metal yielding support with a massif and to definition of support pressure loads are spent to 60-70th years of 20th century of prof. Y.Z. Zaslavsky, prof. I.L.Chernjakom and prof. J.U.M.Liberman.

At Institute of Mining of A.A.Skochinsky (Lyubertsy) under the direction of prof. M.N.Geleskula and prof. E.S.Kiselyov approximately the same years have been studied questions of increase of labour productivity and economy of metal on developments, new steel yielding supports of type МПК, МИК with in pliability knots are created.

The Tula State Technical University has been developed by school of thought of prof. V.N.Karetnikova and V.B.Kleymenov methods of the automated calculation of a support as spatial system, new elements for spatial strengthening of the constructions, improved special profile СВПУ are offered, etc. Original, researches are spent at the St.-Petersburg State Mountain University of prof. V.V.Smirnjakovym which one of the first has created pliable knot of connection of bearing elements of a support and has developed a number of supports of the raised pliability.

At development of coal deposits of the Western Donbass where developments were driven and maintained in weak, inclined to rocks, the big contribution to perfection of constructions and technology of erection of steel frame supports was brought by scientists: prof. A.P.Maxim (НГА Ukraine), prof. G.S.Pinkovsky (Dneprogiproshakht), prof. B.M.Usachenko (IGTM АН of Ukraine), prof. J.M.Halimendik, prof. V.I.Bondarenko (NSU), etc.

Standard materials by calculation and support application in mine workings have been developed in LISTEN (S.-Peterburg) and НИИОМШС (Kharkov) under the direction of prof. I.G.Koskova and prof. V.P.Druzhko.

The big contribution to a solution of a problem of management of efforts in frame supports, mining of ways and means of increase of working capacity of constructions, mining of methods of an estimation and the forecast of interaction of a support and containing massif was brought by scientific DonGTU (Alchevsk): prof. G.G.Litvinsky and G.I.Gajko. [2].

The problem of a decrease of the expense of metal in steel frame supports by application of anchors is solved in KuzNIIshahtostroe of prof. Erofeevym L.M. (Kemerovo).

The big variety of constructive solutions of steel frame supports and considerable range of their performance data, allowing to select constructions for a wide range of geomechanical conditions of maintained developments, have made frame supports actually a universal remedy of fastening of mine workings.

2.2 Review national sources.

For development workings of coal mines of Ukraine of the most used was and there is developed DonUGI in 70th years of 20th century an arch yielding support from special profiles ISP: triple-link АП-3 (or КМП-А3 and updating with the extended legs) and five-link (АП-5 or КМП-А5). Volumes of application of an arch support in development workings - to 95 % from carrying out total amount. On mines of such developed coal-mining countries as Russia, Poland, Czechia, Germany and China frame supports also are the most widespread constructions.

According to a number of researches (including Y.Z.Zaslavsky) with increase in depth of mining about 500 m to 1000 m of displacement of adjoining rocks in development workings loadings perceived by a support - in 2,0 times have grown three times, and. Despite it (according to V.G.Lisichkin and K.V.Koshelev), in overwhelming majority of the cases, the deformed yielding supports, working outside of the passport operational operating mode, provide residual bearing capacity. Thus the support pressure load, at other-wordly deformation of elements bearing it, is redistributed on frame perimetre, and displacement of elements of a support occur with gradual (stage-by-stage, enough smooth) stability loss, without destructions. The considerable part from initial section of a development (working space) thus remains. All it allows to consider a metal arch yielding support of one of the most safe constructions.

2.3 Review local sources.

According to the researches executed by N.V.Gavrilovym, V.I.Bondarenko and L.V.Bajsarovym, except high reliability, the steel frame support is competitive at fastening cost, conceding only anchor supports which have the limited scope on stability of adjacent strata and mining conditions[3].

At the same time, frame supports applied now have also very essential lacks revealed in the course of their operation. In a number of cases as shows a know-how, conformity to conditions of the big depths and an intensive rock pressure manifestation is noted their complete not. So, according to inspections of a condition of mine workings on the mines spent by DonNTU, the BOTTOM, DonGTU, etc. typical frame supports are deformed and demand repair in 30-50 % of the surveyed developments.

As the fastening system, an arch support has a number of lacks. It actually does not maintain a development until adjacent strata will not collapse and will not start to be dislodged in a development, loading support frames. That is, the support works in a passive mode and does not interfere with destruction of a containing massif. Besides the basic lacks of an arch support are: the big metal consumption; the support does not get into gear right after exposures of a design contour of a development, impossibility of complete mechanisation of process of fastening (a lacing of frames and a backfilling spaces are made manually); not conformity to its conditions (is not present between directions of a pliability of a support and the greatest displacement of a contour of a development)[4].

The spent numerous experimental researches and roadway maintenance experience show what to provide their normal operational condition during all service life it is possible only by use of bearing capacity of the rock mass containing developments. Therefore, application of rockbolt-frame and frame-rockbolt constructions of a support became one of perspective directions of perfection of frame constructions last years.(fig. 1).

Figure 1 – The sequence of works on the construction of frame-anchor
(animation: 8 frames, time delay - 50 ms, 66 Kb)

Extremely a negative consequence of application typical metal in difficult geological conditions, except growth of cost of a roadway maintenance, is the impossibility to increase loading on stope and intensity of working of reserves. So, on mines of A.A.Skochinsky, to Cheliuskintcev, "October", A.F.Zasjadko Mine, "Shcheglovsky-deep", of A.G.Stakhanov, etc. where depth of conducting operations exceeds 900 m, cost of a retimbering 1 item of m of a development on 30 % and more exceeds cost of its fastening at a construction. In conditions above the listed mines all development workings at long-pillar mining method it is obligatory 1 time retembering and at the combined or continuous mining method - 2-3 times. Thus, because of a bad condition of development workings the daily output per face did not exceed 700-800 т.

Perfection of constructions of frame supports last decades developed in following directions:

? reduction of metal consumption of a support;

? the maximum simplification of constructive elements;

? simplification of manufacturing techniques of a support.

Use steels with higher strong properties and rolling profiles with the raised static indicators (КГВ) was priority actions thus. Constructions of fixing frames became simpler at the expense of an electric welding exception on sites legs on a roadway floor, reductions of length elements in locks and quantities of interframe couplers. At profile КГВ, despite a reached decrease of metal consumption of a support on 4 % at constant bearing capacity and increase at 30 % of working resistance safety factor even more low - 1,1-1,2.

Experience of application of steels with higher strong properties has been directed on a decrease of the size of a profile on a step at the same section. However thus working support resistance has decreased on 12-22 %, and at the expense of increase of fragility of a steel deformation of bearing elements of a support has increased.

Other known tendency of development of means of fastening of developments (including frame constructions) last 3-4 decades there is an increase in the area of cross-section section of development workings. So, if in 70th years of 20th century value of the average area of cross-section section for haulage gates did not exceed 11,2 м2 in 2003 it made already 14,8 м2, and now reaches 16-18 м2. According to inspections of a condition of the mine workings, spent to the BOTTOM in 2008-2010, supports with section to 11,2 м2 practically are not used (4 %); with section 13,8 м2 - 37 %; with section 15,5 м2 - 25 %; with section 18,3 м2 - 29 %; and with section 19 м2 and more - 5 %.

It is necessary to notice that frames with cross-section section in clear to 11,2 м2 which most often met 25-30 years ago, now practically are not used, and sections 13,8 prevailing now м2 frequently appear not sufficient and are displaced by sections 15,5 м2 and 18,3 м2. On mines with especially severe conditions of maintenance supports triple links, with the extended legs with section 18,3 м2 are mainly used. At the same time, application experience triple links supports with the extended legs (section 18,3 м2) and fivelinks supports has appeared negative as it was not possible to achieve improvement of a condition of developments. [5].

One more tendency of development of frame fastening is connected with application of heavier profiles. So, by 1983, special profile СВП-14 has grown out of use, and the specific volume of application special profile СВП-17 has decreased in 5,9 times (from 20 % to 3,4 %). By 2003, СВП-17 also has grown out of use. From year to year the volume of application СВП-19 is reduced. The basic standard sizes now are СВП-22, СВП-27 and СВП-33 that is connected with increase in average sections of maintained developments of the big sizes made of profiles.

In the course of inspection of a condition of supports on mines of the Western Donbass spent by V.J.Kirichenko, the manufacturing tendency metal support from heavier standard sizes of a profile has been revealed, than it is necessary on specifications. It speaks aspiration of production workers to raise bearing capacity of typical frame supports. Such extensive tendency of development of frame fastening is ineffective and connected with absence of alternatives at a choice of type of a support. Result of such approach was the negative tendency of increase in density of installation of a frame support which already has now led to growth of metal consumption of a support to 1,2 tons on 1 item of m of a development. [6].

Last decades steadily there is a change of a geomechanical situation at working of coal seams on the big depths. Increase not only displacement of rocks containing development, character and intensity proceeding in a massif of deformation processes containing developments changes. It results not only in sharp increase in expenses at a roadway maintenance, but also practically brings to nothing one of the basic advantages of the most perspective of the long-pillar and combined mining methods providing at an output per face of 3,0-3,5 thousand of tons a day necessary profitability of working of reserves. At the same time, the volume of their application on mines of Ukraine in 2012 has made more than 80 %, and volume of coal extracted there ? more than 90 % with use of modern longwall sets of equipment. However daily outputs per face only in 50 % of cases exceed 1500 t/day, blocking the minimum threshold of a recoupment of such complexes as 3КД-90.[7].

It is necessary to consider as a principal cause of such situation not a satisfactory condition of all maintained conveyor and air workings, including at level «longwall windows». Now to 55 % of local expenses it is necessary on repair and maintenance of entries, and also a complex of operations on interfaces. Use for maintenance of belt roadways of the old typical frame supports, having power new conditions power and kinematic characteristics does not allow to provide efficiency of working of reserves at long-pillar mining method.

One of radical ways of solution of this problem is transition on empty technology, with an offset of end drives face the conveyor in limits of section of entries. However this condition in a new geomechanical situation, at use of steel supports of old type, began an absolute obstacle to provide at problem solution high technical and economic indicators of operation mining sites. According to experts, the most perspective the tendency directed on increase of bearing capacity of a support at the expense of change of the form of cross-section section of a development and type of a frame construction is considered. [8].

Till 80th years of 20 centuries, in Ukraine, the idea of creation of frame supports of the elliptic form was considered not realizable for the techno-technological reasons. The developed three-articulated bars КС-4 which has driven successful approbation on mine «Yuzhnodombasskaya №3» in 1994-1995 became transitive technical solution

In the early eighties the last century two constructions of the frame support which is coming nearer under the form to an ellipse have been developed: КЭП and КШПУ. The support of type КЭП has been developed by MakISI and successfully used in system Ukrshahtostroja. However, for fastening of drifts it has not approached because of the limited pliability (from 120 to 200 mm). Support КШПУ has been created for conditions of the Western Donbass and in comparison with АП-3 has shown the best bearing capacity and higher stability.[9].

The further development the tendency of change of the form of cross-section section of developments has found at mining five-links supports of type КМП-А5С (the developer Donbass NC at AGN Ukraine) and four-links supports КМП-А4К (developed on the basis of experience of application of frame supports on mines of Germany). However these constructions of a support of a wide circulation have not received because of necessity to have in working face the additional equipment for adjustment and more difficult technology of assemblage.[10]. .

Conclusions

Analyzing volumes and scopes of steel arch supports, quantity of let out constructions, and also the inventions prolonging term of operation of frame constructions, prof. G.G.Litvinsky does a conclusion about their S-shaped character of development in time, as any technical system. As the system has already driven an initial stage of fast perfection and the subsequent stage of stable growth rates of its development start to fall down though application volumes are still high enough. Further, according to «the law of life of technical systems», a steel frame support most likely essentially other system of fastening (anchor, lifting rock constructions, etc.). However, the next 10-20 years it is improbable because of high inertial mining industry developments. It is more probable that the frame support will pass to essentially higher level of the technical development.

The most perspective directions of perfection of metal frame fastening for development workings is change of the form of cross-section section and a support construction, and also use of the combined constructions on the basis of the anchor systems allowing at the expense of drawing of adjacent strata in teamwork with a support is essential to increase its bearing capacity.

References

  1. Касьян Н. Н., Петренко Ю. А., Новиков А. О. О перспективах применения анкерной крепи наугольных шахтах Донбасса //Научные труды ДонНТУ. - 2009. №10. - ст. 109-115;
  2. Г.Г. Литвинский, Г.И. Гайко., Н.И. Кулдыркаев. Стальные рамные крепи горных выработок. – К.: Техніка, 1999. – 216 с.
  3. М. Месарович., Мако Д., И. Такахара. Теория иерархических многоуровневых систем: Пер. с англ. – М.: Мир, 1973. – 334 с.
  4. Инструкция по выбору рамных податливых крепей горных выработок. Изд. 2-е, перераб. и доп. – СПб., 1991. – 125 с.
  5. Г.Ю. Альбертс., К. Цастрау. Проходка горизонтальной породной выработки с использованием нового австрийского способа туннелестроения // Глюкауф, 1981. – № 7. – С. 20–26.
  6. В.В. Виноградов. Геомеханика управления состоянием массива вблизи горных выработок. – К.: Наук. думка, 1989. – 192 с.
  7. Б.А. Картозия., В.А. Пшеничный. Теоретические основы крепления горных выработок крепью регулируемого сопротивления // Специальные способы строительства подземных сооружений и шахт. – М.: МГИ, 1984. – С. 600.
  8. А.В. Быков. Ускорить внедрение крепей регулируемого сопротивления на шахтах Донбасса // Шахтное строительство, 1986. – № 3. – С. 3–8.
  9. В.Г. Горохов. Методологический анализ системотехники. – М.: Радио и связь, 1982. – 160 с.
  10. Терещук Р.Н. Состояние и перспективы применения анкерной крепи //Научный вестник. - 2000. - №2. - С.6-9;