Abstract
thesis of final work of master’s degree :
«Calculation procedure of the parameters of the advanced concrete lining while building of underground facilities»
Supervisor: Boris Artemovitch Lysikov, candidate of engineering sciences, Professor
Work immediacy
Correct lining of mine roadways is one of the main links while building of underground facilities and it is directly connected with the risk of rock falling. The reasons of similar accidents can be different and it is often very difficult and very expensive to eliminate their consequences and sometimes tens of millions of American dollars are required to do this. That is why a correct choice of the system of mine roadways lining while driving mine workings directly influences the life time and cost of mine workings operation.
Work purpose
The purpose of the given master’s degree work is to create the calculation procedure of the parameters of the advanced concrete lining (ACL – further in the text), its composition and the most effective technology of lining setting to reduce expenditures and increase the life time of lining operation taking into account the detailed project study and perfect performance of mining development work on the stage of geological and hydrogeological researches.
Investigation methods
The investigation method is a complex one. It includes the following:
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the system analyses of materials of other authors’ investigations in this sphere,
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modern experience in the sphere of lining of mine roadways in poor mine rocks,
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studying of current data and literature ,
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computer modeling and
carrying out of laboratory investigations and experiments.
Investigation object
Investigation object is the phenomenon of integrity failing of the advanced concrete lining of mine roadways developed in the poor mine rocks.
Investigation subject
Investigation subject is the parameters and composition of the advanced concrete lining providing the operation increase of the lining in the difficult mining-geological conditions.
Scientific novelty of the work
The given work presupposes to create the calculation procedure of the parameters of the advanced concrete lining, its composition as a part of the technology of mine working development in the difficult mining-geological conditions. This calculation procedure can be the contribution to the mining science.
Useful purport of the work.
Useful purport of the work is that the calculation procedure of the parameters of the advanced concrete lining and its composition has been created as well as the necessity to take into account the consistency factor of ACL has been proved. The backgrounds to design ACL with the set level of reliability for definite mining-geological conditions have been created.
The essence of ACL application.
The essence of ACL application is that the temporary lining is created preliminary ahead of the working face. This temporary lining is done by concreting using the method of spraying the preliminary created curved gap which is 3-4 meters long and 10-20 centimeters high. The gap is done under a slight angle (4-12) to the longitudinal axis of the tunnel to provide the possibility to set the subsequent sections of the ACL. In comparison with the traditional supports (arch, anchoring, concrete sprayed) ACL stabilizes the mine rocks before developing and prevents the rocks from movement. The rock excess is practically absent due to the even outline of the curved gap, the deformation of the rock massif and ground surface is minimum and the development rates increase. ACL is a part of the permanent tunnel structure while the other types of supports fulfill only temporary functions.
The cost of building using ACL is 40 -60 % less than using traditional ways. ACL is recommended to apply in mild hard-rocks, semi- hard-rocks and soft rocks with the strength coefficient 2-5 according to M.M. Protodyakonov.
The technology in question is successfully used to build metro, railway and highway tunnels in France, Italy, Spain, Switzerland, Venezuela and Japan. The underground station “Admiralteyskaya” in St.Petersburg has also been built using ACL.
To make the curved gap the specialized equipment with the jib executing organ has been designed to work with rocks of different strength. While in France using ACL some types of gap making machines were used. The machine for in hard rocks was designed by French companies “Supremech”and “Perforex” and manufactured by the company Sershar”. This machine consists of an frame under which there is enough space for free movement of the equipment to mine and load the rocks. The dismountable metal shield is attached to the frame and the shape of this shield corresponds to the shape of the mine working. There are two toothed arched racks in the front and back parts of the frame along which a carriage with jib executing organ moves; the length of the bar is 2,27m. The machine allows to make a gap of 1.9m deep, 80 -100 mm high with the angle not less than 10 0 to the horizontal axis.
The majority of tunnels developed using ACL are in mild hard-rocks, semi- hard-rocks and soft rocks . The tunneling is done with the help of lower bench mining method or longwall face with the mechanized development of rock without explosions.
Depending on the required width of the lining the height of the gap varies from10 to20 cm, and the depth of the gap is determined by the depth of penetration of gap making machine executive organ. The depth is not more than 5 m. But in unstable rocks the depth should be reduced down to 1- 1, 5 m.
In the process of gap making the machine executive organ is bent forward so the gap has the conical shape. It gives the possibility to overlap the adjacent sections of the ACL by not less than 0.3 m and to make the continuous lining. The increase of the overlap length up to 1-1,5 m can rise the carrying capacity of the lining but this greatly reduces the driving rates. As soon as the gap has been made it is filled with the concrete mixture by spraying it into the gap side.
The time of the concrete setting in the gap differs greatly between 4 – 6 hours in Paris metro and 10-15 hours in Japan, tunnel Akiko and 16-17 hours in France , tunnels Fontene and So. After the concrete becomes strong enough (nearly 8 -10 MPa) the rock in the face is developed under the protection of ACL with the application of the tunnel -boring machine with the executive organ of the selective action or with the application of the tunnel excavator. While the rock development ACL is reinforced by steel arches at the distance of 2-2,5 m.
The time period for gap making in semi- hard-rocks and soft rocks is determined by the capabilities of the gap making machine and it is 3-15 minutes with the average speed of operation 1m/min, and the time needed to set one section of the ACL is 3-5 hours.
The tunneling using ACL in the loose poorly stable rocks is similar to tunneling in soft rocks. But the depth of penetration of gap making machine executive organ reduces to 1,5 – 1 m and in some cases to 0,4 m. The tunneling speed using the given technology is 40-60 m/sec.
The method of tunneling using ACL is very perspective in places where the application of traditional technologies can lead to the failure of the rock massif and where it is strictly necessary to observe the ecological rules. This technology can be applied in the wide range of geological conditions (from rocks to loose soils) while tunneling of different shapes and with the cross section more than 30 m2 . While doing this the driving cycle is completely mechanized, the labour safety increases, the environmental damage is minimum, settlement of ground and ground surface is 4-5 times less compared with the traditional ways in the similar conditions.
Other advantages of this technology are its flexibility, good adaptability to changeable geological conditions. The method of tunneling using ACL can be an alternative to the shallow tunneling of the open type in the developed sites of cities.
List of the used literature
1. Geleskul M. N., Karetnikov V. N. Spravochnik on fastening of the capital and preparatory mountain making. M., Bowels of the earth, 1982, 479 p.
2. Lysikov B. A. and othhers. Subway and tunnels. 2002, ¹ 3, – p. 39-41.
3. Perfection of tekhnologiii building of mines and underground buildings. Sb. nauch. labours. it is Donetsk: "North-press", Issue ¹ 11, 2005 – 100 p.
4. Shevchenko F. L. Zadachi on mechanics of the resilient deformed systems: Train aid for the institutes of higher, part 2 / it is Kiev: ISIO, 1996 – 206 p.
5. Lysikov B. A. and othhers. Building of underground passages and underground buildings on the earned additionally territories: Train aid for the institutes of higher, part 1 / it is Sevastopol: "Veber", 2003 – 302 p.
6. Kaufman of L. L., Kuldyrkaev N. And., Lysikov B. A. Stroitel'stvo tunnels. A monograph is in 2th parts. Part II. / it is Donetsk: "North-press", 2006 – 330 p.
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