Tunnel driving method

Abstract: A tunnel driving method using a drill carriage provided with plural number of drill booms having drifters. According to a preferred embodiment, while the drill carriage is placed before a bench, the charging cages are moved to mark blasting holes and rock bolt holes for an upper portion. While the drill carriages are moved backward with a predetermined length, the charging cages are moved to insert the rock bolts for the upper portion. Simultaneously, the charging cages are operated in a lower portion to bore blasting holes for the lower portion. Then, the charging cages are operated to charge the blasting holes for the upper portion and the lower portion with dynamite for blasting so that the facing is broken and a new facing is formed. Subsequently, after first and second operation of concrete shooting, the above continuous operation is performed repeatedly.

Description: Specification The invention relates to a tunnel driving method according to the preamble of claim 1, applied in NATM methods. For tunnel driving and tunnel self-sustenance, NATM methods are conspicious today. As NATM methods, the following methods can be mentioned : (1) a full face cutting method With this method, the full face of a tunnel is driven at once. The method can be performed only when natural ground is stable. (2) a long bench cut method This method is performed when the length of a bench is generally longer than 50 m, natural ground is comparatively stable and invert closure should not be carried out so quickly. This method includes two ways. One way is a simultaneous driving of the upper and lower portions of an inner section. Another way is alternate driving of the upper and lower portions. (3) a short bench cut method This method is performed when the length of a bench is generally about from 15 to 30 m. This method is carried out with blasting treatment or mechanical treatment. (4) a minibench cut method This method is originally performed when invert closure should be carried out quickly due to unstable natural ground and/or the natural ground having large possibility of swelling. Actually, this method is seldom executed. (5) a multistage bench cut method If a tunnel has a comparatively large cross section, the face of the tunnel can not self-sustain by normal bench cut methods. In this case, this multistage bench cut method can be used. (6) a silot method This method is performed when the face of a tunnel is comparatively large and natural ground does not have enough supporting strength against tunnel driving. Further, this method is often utilized driving town tunnels to prevent the settlement of the natural ground. In the prior art, the following problems arise. (1) the full face cutting method This method can not be used when the natural ground is unstable. (2) the long bench cut method As explained before, this method includes two ways. First, in simultaneous driving the upper and lower portions, operation can be progressed in the both portions simultaneously without interval. Thus, it has an advantage that construction period is reliable. However, in the lower portion, many operators and apparatuses are required. Since priority is given to the operation in the upper portion, the operation in the lower portion can not be carried out efficiently. Accordingly, the construction of this method is expensive. Further, due to the simultaneous driving in the both portions, heavy machines and cars may scrape each other, the operators may fall from a slope and muck from cars may hit the operators. Moreover, the work environment of this method is low. For example, when the lower portion is blasted, the air duct may be damaged resulting in incomplete ventilation. Further, blasting, mucking, concrete shooting are performed many times in the upper portion. Thus, dust is often produced in such operation. It is understood from the above description that the simultaneous driving has many problems. On the other hand, in the alternate driving the upper and lower portions, new face is always formed in one portion; the upper portion or the lower portion. Accordingly, as for effectivity, safety and work environment, this alternate driving has advantages. Further, since the same apparatuses and operators can be used in both portions, it can be carried out efficiently. However, when the natural ground is not unstable, it can not be performed smoothly, thus, its construction period can not be reliable. Further, in this alternate driving, it takes long to remove and reset the air duct, electrical wires and the like. (3) the short bench cut method When this method is carried out with the blasting treatment, apparatuses should be prevented from being damaged by blasting operation. Accordingly, a slope must be formed so that the apparatuses can go up and down between the upper and lower portions through this slope. On the other hand, when this method is carried out with the mechanical treatment, it is very difficult to perform invert closure in short time. (4) the minibench cut method With this method, simultaneous operation in the upper and lower portions can not be performed, which means low effectivity. (5) the multistage bench cut method In this method, multiple steps are provided. Accordingly, closure is often carried out lately resulting in large deformation of a tunnel. Further, operations often disturb each other. (6) the silot method In this method, generally, operation and invert closure can not be carried out in the upper and lower portions at the same time. Accordingly, this method requires longer construction time and high construction cost. In the conventional operation with drifters, two drill carriages are used. Thus, machinery cost is increased and the number of operators are doubled. Further, there is a risk to scrape the drill carriages on both sides. On the other hand, recently, many tunnels have large cross sections. In this situation, several drill carriages should be used effectively. However, it is difficult to use several drill carriages. From JP-A-1 287 394 a tunnel driving method for relatively small tunnels is known, which uses one drill-jambo car D provided with pit boring booms 3 having at least two charging cages 6L, 6R and three pit boring machines 1. First, by the cages 6L, 6R, the marking of blasting slot and a lock bolt slot is performed, and after that, an upper half blasting slot and the lock bolt slot are bored by the booms 3 at the same time. After that, the jambo D is moved backward, and by the cages 6L, 6R, an upper half lock bolt 20 is driven, and by the booms 3, a lower half blasting slot and the lock bolt slot are bored through at the same time, and after that, by the cages 6L, 6R, a lower half lock bolt 20 is driven, and in both the blasting slots, a dynamite is set. After that, the upper half and lower half are blasted, and a previous cutting edge is broken, and another upper half cutting edge and lower half cutting edge under a bench are formed. This method is infavorable for large tunnels. It is a problem of the invention to provide a efficient tunnel driving method especially for tunnels with large cross section, that are self-supporting - even in unstable grounds - with a high workability. It is another problem of the invention to provide a tunnel driving method in which machinery cost and the number of operators are low and in which effectivity is extremely increased. The problems are overcome by tunnel driving methods according to claim 1 and 2. The invention uses at least two drill carriages. Each drill carriage is provided with at least two charging cages and at least two drill booms having drifters. The different steps of the embodiments of the methods according to the invention can be seen from the claims. For unstable natural ground bench cut methods are used. Particularly suited for the invention are short bench cut methods. The bench has the length of normally from 2 to 7 m, more normally from 3 to 4 m. Accordingly, when the drill carriage is placed before the bench (or the short bench), the charging cages and the drill booms can reach the upper portion. Then, in the invention, since each drill carriage is provided with at least two charging cages and at least two drill booms, operation can be performed simultaneously in the upper portion and the lower portion or the upper portion and the short bench. Therefore, high effectivity is ensured. Further, in the invention, since blasting is carried out simultaneously, construction time can be decreased. On the other hand, when the cross section is large, according to the above mentioned embodiments of the invention, several drill carriages are placed before the face substantially parallel to the axis of the tunnel. For the simultaneous driving method in the upper and lower portions in the conventional long bench cut methods, as explained before, exist many problems. However, in these embodiments according to the invention, the tunnel driving can be carried out efficiently without the above mentioned problems due to the arrangement of the drill carriages. Moreover, in each embodiment of the invention, the drill carriages are provided with at least two charging cages and at least two, preferably three drill booms having drifters. It is sure that cost of one drill carriage of the invention is somewhat higher than that of the conventional drill carriage. However, to attain the same effectivity, the machine cost of the drill carriages of the invention is extremely lower than that of the conventional drill carriages. The number of operators required in the inventive drill carriage is about 50 % of that required in the conventional drill carriage. Particularly, since each drill carriage is provided with two charging cages, simultaneous operation in a wide area can be performed. Further, the drill carriage has two, more preferably three drill booms. Accordingly, while the rock bolt holes are bored with one drill boom, the blasting holes provided on both sides of the drill carriage are bored with another drill boom, more preferably further two drill booms. Therefore, it is understood that effectivity can be progressed also by the composition of the drill carriage. In the invention, during blasting, the drill carriages must be removed. However, when the blasting is not carried out, each drill carriage always remains on one place. Thus, accidents such as scraping with other heavy machines and other cars can be prevented. Further, the blasting is carried out in the upper portion and in the short bench or in Lne upper portion, the short bench and the low side enlargements simultaneously. Accordingly, dust exposure time can be shortened and ventilation can be performed more smoothly. That is to say, good working environment in the tunnel is ensured. In the prior art, each drill carriage should move between two places in the tunnel. Accordingly tunnel equipments such as air ducts, electrical wires, iron pipes and the like were often damaged due to this movement of each drill carriage. Further, the tunnel equipments must be removed and reset every movement of each drill carriage. It produces large waste and loss. According to the invention, since each drill carriage almost remains on one place in the tunnel, there is no danger for such waste and loss. According to the invention, for a tunnel having large cross section, such as larger than 100 m2, particularly larger than 140 m2, the tunnel driving is carried out as follows. The inner section of the tunnel is divided into work areas; the upper portion, the short bench and the lower side enlargements. Then, in the upper portion and the short benchs, the operation is carried out with two drill carriages substantially arranged in parallel. Then, in the lower side enlargements, operation is carried out with the other drill carriage or machine provided with at least the drill boom and the charging cage. In the prior art, the inner section of the tunnel is divided into just an upper portion and a lower portion if the tunnel has a large cross section. When the method of the invention is compared with this conventional method, it is understood that the method of the invention can be applied for even unstable natural ground more efficiently. Because, after mucking for the short bench, the lower side enlargements still remain. Accordingly, stable driving can be performed without disintegration. Moreover, the operation in the lower side enlargements is carried out to follow the operation in the upper portion and the short bench. Accordingly, operations are not interfering each other and high efficiency can be ensured. Further objects and advantages of the invention will be apparent from the following description referring to the accompanying drawing wherein preferred embodiments of the invention are clearly show. Therein: Fig. 1 is a flow sheet showing the tunnel driving method according to the second embodiment; Fig. 2 is a flow sheet showing the tunnel driving method according to the third embodiment of the invention; Fig. 3 is a cross section of a tunnel according to the invention; Fig. 4 is a front view of a drill carriage; Fig. 5 is a plan view or the right and left charging cages of a drill carriage; Fig. 6 is a side view showing operation in the upper portion; Fig. 7 is a side view showing operation following the operation of Fig. 6 before the short bench; Fig. 8 is a side view showing operation following the operation of Fig. 7 before the short bench; Fig. 9 is a side view showinq operation in an upper portion with a drill carriage, with a drill boom that can be moved vertically; Fig. 10 is a side view showing operation before a short bench with drill carriages, with drill booms that can be moved vertically; Fig. 11 is a top view showing operation in an upper portion, a short bench, lower side enlargements; Fig. 12 is a front view showing the arrangement of drill carriages, with drill booms that can be moved vertically; Fig. 13 is a side view showing the arrangement of drill carriages, with drill booms that can be moved vertically; Fig. 14 is a side view showing mucking, Fig. 15 is a top view showing mucking; Fig. 16 is a top view showing shooting; Fig. 17 is a side view showing shooting; Fig. 18 is a side view showing shooting with a shooting car, with a shooting arm that can be moved vertically; Fig. 19 is a front view showing shooting with shooting cars, with shooting arms that can be moved vertically; Fig. 20 is a top view showing shooting and operation for lower side enlargements carried out simultaneously with only two drill carriages; Now, referring to the drawings, the invention is described more detailed with reference to preferred embodiments. First, the examples of apparatuses used in the embodiments will be explained. Fig. 4 and 5 show a drill carriage D according to the invention. In Fig. 4 only two drill booms 3 are visible. However, as shown in Fig. 11 and 12, the drill carriage is provided with three drill booms. One drill boom is placed at its center and two drill booms are placed at its both sides. In the drill carriage D, the above mentioned three drill booms 3 are provided in the front portion of a cart 4. Each guide shell 2 is supported by each drill boom 3. Each drifter 1 is equipped on each guide shell 2. Slide rails 5L, 5R are laid on the left and right sides of the cart 4. Then, two charging cages 6L, 6R are set on the slide rails 5L, 5R, respectively, to slide on the extending direction of the rails 5L, 5R. The charging cages 6L, 6R comprise slide yokes 7L, 7R, charging booms 8L, 8R and cage sections 19L, 19R, respectively. The slide yokes 7L, 7R can be slide on the slide rails 5L, 5R, respectively. The bottom ends of the charging booms 8L, 8R are pivoted by the slide yokes 7L, 7R respectively to direct upward and rotate. The cage sections 19L, 19R are pivoted by the other ends of the charging booms 8L, 8R, respectively. The charging booms 8L, 8R are rotated by rotation cylinders 10L, 10R, respectively. On the other hand, the charging booms 8L, 8R are directed by direction cylinders 11L, 11R, respectively. Position limit switches LS FL , LS FR , LF RL , LS RR are provided on the cart 4 to detect positions of the charging cages 6L, 6R. When the charging cages 6L, 6R are moved forward to locate at their operating positions, the position limit switches LS FL , LS FR can detect it. On the other hand, when the charging cages 6L, 6R are moved backwards to locate at their containing positions, the position limit switches LS RL , LS RR can detect it. Angle limit switches LS SL , LS SR are provided on the slide yokes 7L, 7R, to detect the limit angles of rotation of the charging booms 8L, 8R, respectively. With the a.m. tunnel driving method during drilling operation, the drill carriages are placed adjacent to a face. Drilling is carried out by the drifters which are equipped on the guide shells supported by the drill booms, while the two charging cages go backward to locate on the containing positions. After drilling, the charging cages are moved forward to locate on the operating positions for charging with explosive. The position limit switches can detect whether the two charging cages locate at the operating positions or the containing positions. Under such location, the charging booms 8L, 8R begin to rotate inward to approach each other. The angle limit switches can detect their angles. Electromagnetic directional control valves are provided on the hydraulic actuation circuit of the rotation cylinder. These valves are controlled by signal from the position and angle limit switches so that the charging booms rotate just with predetermined limit angles. That is to say, the charging booms are prevented from interfering each other due to the control of their rotation angle. For operation with one charginig cage this charging cage should locate at the operating position. On the other hand, another charging cage should locate at the containing position. The limit switches can detect their positions. In this case, even if the charging boom at the operating position rotates inward over the predetermined limit angle, the electromagnetic directional control valves are not controlled so that the charging boom can rotate with a full stroke given by the rotation cylinder. In this situation, since the other charging cage locates at the containing position, there is no interference. <the first embodiment> In the first embodiment two drill carriages D, D provided with at least two charging cages and at least two drill booms having drifters are placed parallel with respect to the axis of a tunnel: (A) First, as shown in Fig. 6, the above mentioned drill carriages D (only one drill carriage is shown) are placed at the center of the tunnel and before a short bench Y located at the foot of a face. In this situation, (A2) the at least two drill booms are operated to bore the blasting holes and the rock bolt holes in the upper portion; (A2) Then, the charging cages 9L, 9R are moved backward once. Subsequently, at least two, preferably three drill booms 3 are operated to bore the blasting holes and the rock bolt holes in the upper portion. In this case, while the rock bolt holes are bored with one drill boom, the blasting holes are bored with the other drill booms. Accordingly, the drill booms are operated simultaneously to give high efficiency for the drilling. (B) Next, as shown in Fig. 7, the drill carriages D are moved backward for a predetermined length, for example, 3 - 4 m. In this situation, (B1) the two charging cages 9L, 9R are moved to insert the rock bolts into the rock bolt holes of the upper portion. At the same time, the at least two, preferably three drill booms 3 are operated to bore the blasting holes and the rock bolt holes in a lower portion under the bench Y. (B2) Then, as shown in Fig. 8, the two charging cages 9L, 9R are operated to insert rock bolts into the rock bolt holes of the lower portion. At the same time, the blasting holes of the upper portion and the blasting holes of the lower portion are charged with dynamite. (C) Subsequently, the upper portion and the lower portion are blasted simultaneously so that the face is broken and a new face of the upper portion and a new face of the lower portion are formed. After this blasting, mucking is carried out. This mucking will be stated in other explanation of other embodiments. (D) Finally, after-treatments such as concrete shooting are carried out. Thus, operation of steps (A) to (D) repeated. The operation is carried out in forward portions with respect to the drill carriages D arranged in parallel respectively. In the embodiments including the second embodiment stated hereinafter, the tunnels mainly have large cross sections. Accordingly, as shown in Fig. 3, the cross section of each tunnel is divided into an upper portion X, a short bench Y, lower side enlargements Z. <the second embodiment> Fig. 1 is a flow sheet showing the second embodiment of the tunnel driving method with three drill carriages according to the order of steps. As shown in Fig. 6 to 11, at least two, preferably three drill carriages are used (See Fig. 11) in this second embodiment. Then, each drill carriage is provided with at least two charging cages and at least two, preferably three drill booms having drifters: (A)First, as shown in Fig. 6 and 9 (in these figures only one drill carriage is shown), the two drill carriages are placed at the center of the tunnel and before the short bench Y, which is short of 3 - 4 m and which is located at the foot of the face. In this situation, (A1) the two charging cages 9L, 9R are moved towards the upper portion to mark blasting holes and rock bolt holes for the upper portion X. At the same time, lifter holes and sub-lifter holes can be formed in the upper portion X. (A2)Then, the charging cages 9L, 9R are moved backwards once. Subsequently, at least two, preferably three drill booms 3 are operated to bore the blasting holes and the rock bolt holes for the upper portion. In this case, while the rock bolt holes are bored with one drill boom, the blasting holes are bored with the other drill booms. Accordingly, the drill booms are operated simultaneously to give high efficiency for the drilling. (B)Next, as shown in Fig. 7, 8 and 10, the drill carriages D are moved backward with a predetermined length, for example, 3 - 4 m. In this situation, (B1) the two charging cages 9L, 9R are moved to insert rock bolts into the rock bolt holes for the upper portion X. At the same time, the suitable number of, for example, three drill booms 3 are operated for a short bench Y other than the lower side enlargements Z to bore the blasting holes of the short bench Y. However, the rock bolts can be inserted into the rock bolt holes at the back and center of the upper portion X in the step (A2). That is to say, right after boring and before the drill carriage D is moved backward, the charging cages are moved for inserting the rock bolts. An mortar injection car A (See Fig. 7) is used for fixing the rock bolts. (B2) Then, the two charging cages 9L, 9R are operated to charge the blasting holes for the upper portion X and the blasting holes for the short bench Y with dynamite. (C) Subsequently, as shown in Fig. 14 and 15, the upper portion X and the short bench Y are blasted so that the face is broken and a new face of the upper portion and a new face of the short bench are formed. After blasting, mucking is carried out. Reference numbers 40 and 41 indicates a wheel roller and a dump truck respectively. (D) With shooting cars 31, 31, as shown in Fig. 16 to 18, the first and second operation of concrete shooting is carried out. Refernce number 42 indicates a truck for carrying concrete to be shot. After shooting, operation of steps (A) to D) is carried out according to its order with the two drill carriages D. (E) On the other hand, during operation in the step (B2), following operation is carried out. As shown in Fig. 11, another drill carriage D' is placed before one lower side enlargement Z. In this situation, blasting holes for the lower side enlargement Z and the rock bolt holes on the side walls of the lower side enlargement Z are bored. Then, rock bolts are inserted into the rock bolt holes and the blasting holes are charged with dynamite. After this continuous operation is finished in the lower side enlargement Z, the other drill carriage D is moved to another lower side enlargement so that this continuous operation is performed there. (F)When blasting of step (C) is carried out, the other drill carriage D is moved away from the lower side enlargement Z for blasting in the lower side enlargement Z. (G)Then concrete is shot for the lower side enlargement Z. After shooting, operation of steps (E)to (G)is carried out according to its order with the other drill carriage D'. In this case, as shown in Fig. 1 and 15, mucking of the upper portion X, that of the short bench Y and that of the lower side enlargements Z, are performed simultaneously. Then, the first operation of concrete shooting for the upper portion X is carried out. Next, the first operation of concrete shooting for the lower side enlargements Z, is carried out, while timbering is constructed in the upper portion X. Subsequently, the second operation of concrete shooting for the upper portion X is carried out, while timbering is constructed against the both side walls of the lower side enlargements Z. Next, the second operation of concrete shooting for the lower side enlargements Z is carried out. On the other hand, when the above mentioned second operation of concrete shooting in the upper portion X is finished, the two drill carriages D are moved forward to locate before the face of the short bench Y so that the operation explained above for a next face is carried out repeatedly. One shooting car having one shooting arm can be used to shoot concrete against the whole cross section. However, as shown in Fig. 17, a shooting car 31 having two shooting arms 30L, 30R can be used in a preferable embodiment. More preferably, since the cross section of the tunnel is large, as shown in Fig. 16, 18 and 19, two shooting cars 31 are used. Each shooting car 31 is provided with shooting arms 30L, 30R with its attaching head 32 which can move vertically. For right-side and left-side portions of the tunnel, shooting can be performed simultaneously with these shooting cars resulting in high effectivity. In this tunnel driving method of the second embodiment, the operation in the lower side enlargements Z is carried out with the other drill carriage D'. However, this operation can be performed with another machine having at least a drill boom and a charging cage. <the third embodiment> In the third embodiment, a tunnel driving method with only two drill carriages is described. The same operation as the operation in the steps (A)and (B)of the second embodiment, and the same blasting as the blasting in the step (C)also of the second embodiment, are carried out for the upper portion X and the short bench Y. Then, after mucking, as shown in Fig. 2 and 20, the shooting cars 31, 31 are located before the new short bench Y for concrete shooting for the upper portion X and the new short bench Y. During concrete shooting, the drill carriages D are moved forward to locate before the lower side enlargements Z to bore blasting holes of the lower side enlargements Z and rock bolt holes of the side walls of the lower side enlargements Z. Then, the rock bolts are inserted into the rock bolt holes and the blasting holes are charged with dynamite. Subsequently, the drill carriages D are moved away from the lower side enlargements Z to blast the lower side enlargements Z and mucking is performed. After concrete shooting for the upper portion X and the short bench Y, the shooting cars 31 are moved to locate in the lower side enlargements Z to shoot concrete against the side walls of the lower side enlargements Z and timbering is constructed there. When concrete shooting is finished, the operation explained above is carried out for a next face repeatedly . For tunnel driving performed according to the flow sheet of Fig. 2, the operation for the lower side enlargements Z can be carried out with another machine instead of the other drill carriage D'. This machine is provided with at least a drill boom and a charging cage. When the cross section of the tunnel is large, it is needless to say that operational areas in the upper portion X and the short bench Y are also large. Thus, as shown in Fig. 10, 12 and 13, an attaching mount 3Q of the three drill booms 3 having drifters is preferably provided on each drill carriage D to move vertically. If desired, in this method, larger number of drill carriages, charging cages and drill booms can be used. While preferred embodiments have been described, it is apparent that the invention is not limited to the specific embodiments thereof.

Claims: Tunnel driving method comprising the continuous sequential repetition of the following steps : (A) placing at least two drill carriages (D) each having at least two charging cages (6L, 6R, 9L, 9R) and at least two drill booms (3) with drifters (1) at the center of a tunnel before a short bench (Y) at the foot of a face and between two side enlargements (Z) which extend further backwards than the short bench (Y); (A1) marking blasting holes and rock bolt holes by the charging cages (6L, 6R, 9L, 9R) in an upper portion (X) of the face; and (A2) boring blasting holes and rock bolt holes in the upper portion (X) by the drill booms (3); (B) moving the drill carriages (D) backwaras for a predetermined length; (B1) inserting rock bolts into the rock bolt holes in the upper portion (X) by the charging cages (6L, 6R, 9L, 9R), while the drill booms (3) bore blasting holes in the short bench (Y); (B2) charging the blasting holes in the upper portion (X) and in the short bench (Y) with dynamite by the charging cages (6L, 6R, 9L, 9R) (C) blasting said upper portion (X) and said short bench (Y) so that new faces in the upper portion (X) and in the short bench (Y) are formed; (D) carrying out after-treatments; (E) boring blasting holes in the lower side enlargements (Z) and rock bolt holes in the side walls of said lower side enlargements (Z)and charging the blasting holes with dynamite; (F) moving all carriages/machines away from the blasting site and blasting said lower side enlargement (Z); (G) performing aftertreatment. Tunnel driving method comprising the continuous parallel repetitions of the two groups of steps (A to D) and (E to G); (A) placing at least two drill carriages (D) each with at least two charging cages (6L, 6R, 9L, 9R) and at least two drill booms (3) with drifters (1) at the center of a tunnel and before a short bench (Y) at the foot of a face and between two side enlargements (Z), which extend further backwards than the short bench (Y), and (A1) moving said two charging cages (6L, 6R, 9L, 9R) toward an upper portion (X) to mark blasting holes and rock bolt holes in said upper portion (X) and (A2) operating said at least two drill booms (3) to bore blasting holes and said rock bolt holes in said upper portion (X); (B) moving said two drill carriages (D) backwards for a predetermined length and (B1) moving said two charging cages (6L, 6R, 9L, 9R) and inserting rock bolts in to said rock bolt holes in said upper portion (X), while said two drill booms (3) are operated in a short bench (Y) to bore blasting holes therein; and (B2) operating said two charging cages (6L, 6R, 9L, 9R) to charge said blasting holes in said upper portion (X) and said blasting holes in said short bench (Y) with dynamite; (C) blasting said upper portion (X) and said short bench (Y) so that said face is broken and a new face of said upper portion (X) and a new face of said short bench (Y) are formed; (D) carrying out after-treatments; (E) placing another drill carriage (D) or a machine provided with at least one charging cage and a drill boom (3) before the lower side enlargements (Z) for boring blasting holes therein and rock bolt holes in the side walls of said lower side enlargements (Z) while steps A to B are performea, inserting rock bolts into the rock bolt holes and charging the blasting holes with dynamite while step (B2) is performed; (F) moving said other drill carriage (D) away from the lower side enlargements (Z) and blasting said lower side enlargements (Z) together with the upper portion (X) and the short bench (Y) so that a new face of the upper portion (X) and of the short bench (Y) are formed; (G) aftertreatment of the lower side enlargements (Z) together with step (D). Tunnel driving method according to claim 2, wherein: (G) concrete shooting is started after blasting so that a new face of said upper portion (X) and of said short bench portion are formed.

Inventors: FUKUNAGA NOBUYUKI, ISHIDA YOSHIAKI, KIMURA MUTSUHIKO, METOKI YASUO, SAITO TAKEO, FUKUNAGA, NOBUYUKI, ISHIDA, YOSHIAKI, KIMURA, MUTSUHIKO, METOKI, YASUO, SAITO, TAKEO
Applicants: SATO KOGYO, SATO KOGYO CO., LTD.
Application year: 1991
Main classification: E21D9
IPC codes: E21D9