Geniş kesitli galerilerde klasik sistem ve mekanize sistemle galeri açmanın ekonomikliğinin araştırılması

Abstract

Günümüzde gerek madencilikte gerek inşaat sektöründeki yeraltı kazılarında patlayıcı madde halen yaygın kazı aracı olarak kullanılmaktadır. Esas olarak 1975 'li yıllardan sonra tünel açımında mekanize araçlar yaygınlaşmaya başlamıştır. Tünel ve galeri kazısında her iki sistemin kullanılması kazı metodunun seçimi için tasarımcıya bu sistemlerin avantaj, dezavantaj ve ulaşabilecekleri günlük ilerleme hızları hakkında fikir vermeyi gerektirmektedir. Bu çalışmada patlayıcı madde ve makina ile tünel ve galeri kazısında günlük ilerleme hızlarına bağlı olarak bir ekonomiklik araştırması yapılmıştır. Ülkemiz madencilik endüstrisi gözönüne alındığında bu çalışmadan şu sonuçlar elde edilmektedir: Patlayıcı madde ile kazı, gelişmiş maden endüstrilerinde artık klasik değil elektrikli ekipmanların kullanıldığı modern bir kazı yöntemidir. Patlayıcı madde ile kazıda ülkemizde ulaşılan ilerleme hızları çok düşük olmasına rağmen gelişmiş ülkelerde bu değer ülkemizdekinden en az 5 kat fazla olmaktadır. Ayrıca çeşitli teorik çalışmalarda bunun daha da arttırılabileceği üzerinde durulmaktadır. Patlayıcı madde ile kazı her türlü jeolojik değişimlere kolay uyum gösterebilirken mekanize kazı için tünel hattındaki formasyonların jeolojik ve jeomekanik özelliklerinin çok iyi tanımlanması gerekmektedir. Formasyona uygun seçilmemiş bir makinanin ekonomikliğinden bahsetmek söz konusu değildir. Ülkemiz kömür endüstrisinde patlayıcı madde ile galeri açmanın iyileştirilmesi yapılmaksızın, mekanize galeri ' açımına geçilmek istenmektedir. Yöntemin yüksek ilk yatırım gerektirmesi, ve istenilen günlük ilerleme hızlarının elde edilememesi durumunda büyük ekonomik kayıplarla karşılaşılması söz konusudur. Tam cepheli galeri açma makinaları madencilikte çok kısıtlı bir uygulama alanı bulmuşlardır. Dolayısıyla günlük ilerleme hızlarından bahsederken bomlu makinaların ilerleme hızları gözönüne alınmalıdır.

THe main purpose of this study is to investigate op timum working conditions both drivage by blasting and machine, also to put out which system is more economic than the other. From this point, design parameters for each stages of shotfired drivage determined than a theoritical roadway having 22,2 m2 cross section has been designed. The first stage of a blasting operation is drilling the holes needed to charge the explosives. Before this operation the number of holes have to be calculated carefully. The number of holes needed for each rock type is diffucult to estimate accurately without field tests. Besides, the rock varies along a tunnel, and the number of holes may haveto be changed correspondingly. However it Should be worth trying to optimize the number of holes, especially in long tunneling or roadheading. Needed number of holes, which have to break the rock in a suitable granulemetry for loading and transport work, is effected by the physical properties of the rock formations, size of drill hole diameter and tunnel cross section and they also shield the blastholes from each others which reduces the pressure desentization. These typeof parellel burn cut is shown at Figure-2.17.b. After drilling the blasting holes and relief holes spesific charge of the explosives should be calculated. In Figures- 2-20 spesific charge is given in relation to rock physical, mechanical properties and tunnel cross section. Additionally a general quide to a successful blasting is given as a summary. -xi- When the blasting operation done, about 15 minutes spend on ventilation, and loading operation start. Nowadays almost all roadway drivages are equipped with side discharge loaders and slusher loaders. Loader capacities range from 0,5 to 1,5 m3 of debris per minute, or about 35 m3 of in-sitii rock per hour. Loaders can also be used in transport of the debris. The upper limit for using loader in transport work is seems to be 150 m. The economics of the other alternatives have to be calculated for long distances. An detailed calculation about loading and transporting capacity of loaders is given. If there is no transport work the calculation method can be adapted just for loading capacity. Figure- 2.8 gives the total number of holes according to tunnel cross section, compressive strength or hardness of rock. The use of -larger diameter cartridges would permit a basic reduction in the number of holes. Figure ~ 2.7 shows decrease the total number of holes needed per pull when the diameter of holes increase. An increase in shothole diameter would allow considerable reduction in the number of shot holes; this would mean correspendingly saving in the time needed for drilling and firing out. For drilling operation, drillibility of rock is important and have to be determined in order to choose right drilling equipment. Two tests is introduced in order to determine drilibility of rock. Additionally some of the rocks drillibility index is given at Figure-2v5 Nowadays hydrolic jumbo having single or twin booms each of them with over 2 m./min. drilling capacity is making easy this operation. Obtaining a smooth final wall is very important economical point of view in tunneling. The technigues most commonly used to control damage in the final walls of tunnels are smooth blasting and presplitting. -xii- One parameter, which effecting directly to the daily drivage speed, is type of burn cut. The most advantages burn cutting system} parallel burn cutting with three relief holes provide a large expansion volume for the blasthole. The last and longest time spent on support setting. When attempting to improve shotfired heading operations the most urgent reguirement is to reduce the time spent on support setting, which accounts for almost half of the total time expenditure (48 %). At the same time, however, supportwork remains the most difficult operation to mechanize. This situation is a^- "aveted by the fact that continuous increases in roadway cr^s - section have led to heavied arch sections, and reuuced arc - setting distances. Two suggestions are given about reducing the support setting time: 1 - Mechanization of Arch Setting. 2 - New Support Techniques. After trying to optimize each stage of the shotfired drivage a model roadway has been designed. (Figure- 2.24 ) In these model 4,5 m/d drivage speed have been obtained by using 3 m pull. The result was also suitable for organizing the_ drivage team. for rhytmic working (see Figure -.2. 25 ). By using Üre sane principles the calcuLatiai adapted to 30 - 40 - 50 m2 tunnel cross seçtim far excavatiai in different kind of rock fannatians. The mechanized tunnel drivage has many advantages compared with shotfired drivage; these are as follows, the economy, high advance rates and less overbreak. The chock vibrations are also eliminated when roadheaders are used. It must be strongly emphasized that all these advantages are realized if the roadheaders are selected according to the cuttability properties of the rock formations. Furthermore the initial investment, assembly and disassembly costs of these machines are rather high, these make the minimum length of tunnel to be driven at once very critical. In other words any succes of the roadheaders depend on the geotecnical properties of rock formations in addition to the human and machine factors. -xiii- Tunnel boring machines may be classified as full face machines and boom type roadheaders. Roadheaders are type of machine that widest use today in undergraund operations. Besides the majority of tunnels consructed in the United Kingdom are driven by boom type tunneling machines. Unfortunately, they are limited in terms of the strength and abrasivity they are able to excavate economically. Roadheaders can also be classified according to their cutter head design. The first class consist of forward attack designed cutter head and the second radial. In hard and abbrassive rock it is suggested to use radial designed cutter head. Because they give higher efficiency, in 1988, 73 % of the road headers, used in German undergraund coal mine, were this type. İn Table-3.2 both type of roadheaders design parameters is given in relation to rock properties. According to table the main criteria cutting the rock effectively by radial designed head is cutting speed. It differ from forwad attack designed head which rock condition and cutting force most effective on the excavation performance. Again from the German undergraund coal mine operations, obtained daily drivage speed with in years is given at figure 3.3 it seems that there is no improvements in daily drivage speed of the road headers. Two reason is given behind this unsuccess; a) the increase the roadway cross section bring about more rock to excavate, b) they are used to excavate more hard rock than before. Different type of roadheaders and their performance such as daily drivage speed and machine working efficciency (time) is given at Table 3.3 A, 3.3.B. By referring to early performance of Paurat E 134, daily drivage speed for a roadway having a cros section 22,2 m2 in sandstone and shist formations, has been estimated as fallows: min. daily drivage speed. 4. 66 m/d mean " " " 6. 66 m/d max. " " " 8. 66 m/d. On the other hand full face tunneling machines are also used in mining industry. But their number is not more than a few. Big investment cost, short drivage length are stricted their use in mining- industry. -xiv- In the Section 4 cost analysis for both classical and mechanized drivage technigues has been done and compared with each other. It seems that; if the driving machine selected - suitable to the rock condition and jobsgo well, mechanized driving more economic than classical tunnel driving (see figure 4.2). Obtained resuls are given in the section 5.