KR101148331B1 - Excavation method for pre-nailed tunneling - Google Patents

Abstract

The present invention is carried out by the sun nail nail tunneling method, after construction and installation of the sun nail nail on the ground surface of the tunnel to be excavated, excavation of the tunnel (hereinafter referred to as 'outdoor beam nail tunnel') or large cross section After pre-drilling and constructing the pilot tunnel 20 in the tunnel, the pilot nail 20 is installed and installed in the main section tunnel in the pilot tunnel, and then the main tunnel 10 is enlarged and excavated (hereinafter referred to as 'inner beam nail nail tunnel'). In the case of the construction of the nail nail in the tunnel nail nail tunnel, the hollow beam 30 at the top end and the excavation is added to the planned membrane face at an angle of 90 ° to 180 ° depending on the independence of the ground. After blasting by combining the horizontal perforated hole (40), horizontal enlargement hole (50) and the horizontal bottom hole (60), and then blasted in the order of empty beam-horizontal enlargement hole-horizontal outer hole-horizontal hole About excavation method of nail nail tunnel It is.

In addition, in order to facilitate workability, lengthen excavation length per blast, and simplify membrane excavation, the tunnel is designed once by adjusting the nail spacing and length so that the ground can be freely installed only in the good ground condition over soft rock. Modeling and analyzing excavation of one or more membranes without blasting excavation field and additional support; Constructing a sun nail before the main tunnel excavation; Complete excavation of the excavation site per blasting with only the scalp nails, and securing the independence with only scalp nails on the soft rock over the ground, which consists of blasting and constructing one or more curtains according to the design and ease of work. The present invention relates to an excavation method of a sunbeam nail tunnel.

Sunjibo Nail Tunnel Excavation, Large Section Tunnel

Description

Excavation METHOD FOR PRE-NAILED TUNNELING}

The present invention is to provide an additional technology to the "preliminary beam tunnel method and the device suitable for it" of the Republic of Korea Patent No. 10-0740200, which is a construction method for the construction of the out-of-figure nail nail tunnel or the construction of the inner beam nail nail tunnel It relates to an excavation method.

In tunnel digging, it is possible to expect the maximum digging effect with minimum charge by utilizing the free surface of the pilot tunnel pre-drilled in the inner nail nail tunnel, and to excavate once per blast in the outer and inner nail nail tunnel. When it is possible to excavate to the maximum, and multi-stage digging digging the membrane, it is possible to excavate the top and bottom half or shear surface excavation method of the nail nail tunnel can be easily and safely constructed.

Conventionally, the most important element in the blasting technology for tunnel excavation is the blasting of the deep hole to define a predetermined size area in the center of the membrane surface and to blast first to form a free surface. At this time, it is no exaggeration to say that the difficulty of tunneling is determined according to the size and shape of the free surface.

The conventional blasting method requires the primary blasting of the heart hole to form a free surface, and the second blasting to excavate the tunnel at a time difference is ignited at the primer at the same time.

Conventional tunnel excavation method is applied to a single excavation site and membrane excavation method from a multi-stage digging excavation to a shear surface excavation method in accordance with the conditions of the tunnel base, but a multi-segment excavation is applied in large cross-section tunnel.

Therefore, the present invention is to solve the above problems, an object of the present invention in the prior art by utilizing the free surface using a pre-excavated pilot tunnel before digging the main tunnel of the large cross section in the tunnel nail nail tunnel It is possible to omit the core hole, which is an important factor, and to reduce the amount of drilling by blasting using the sun beam blanks created by constructing sun beam nails outside the excavated surface of the large cross section main line tunnel for economical construction. In addition, it is possible to excavate the excavation site as much as possible once per blast in the pre-inner beam and out-of-gang information nail nail tunnels, while minimizing the amount of over-drafts that increase as the excavation site increases.

After excavation with only the nail nail, the tunnel is completely independent without additional support in the gang to remove the hassle of work according to the additional support and to facilitate the excavation.

In addition, by using a U-shaped measuring instrument in the tunnel nail nail tunnel to improve the workability by pinpointing the position of the hollow hollow hole.

In order to realize the above object, the present invention has developed a method of drilling a shipboard tunnel as follows.

In the construction of the inner beam nail nail tunnel, the horizontal beam hole 40, the horizontal expansion hole 50, and the horizontal beam hole 30 in addition to the hollow beam hole 30 of the top end portion created while constructing the nail beam nail in the pilot tunnel, and the scheduled membrane surface After combining the perforated horizontal bottom hole (60), it is characterized by blasting in the order of empty beam-horizontal expansion hole-horizontal outer hole-horizontal bottom hole. At this time, as the excavation length increases, the heat transfer holes 31 are drilled in the same direction in the front row of the hollow beams, so that the blasting can be controlled.

Also, when designing a tunnel when constructing an out-of-the-ground beam nail tunnel or an in-ground beam nail tunnel, when the ground is in good soil conditions over soft rock, the nail spacing and length are adjusted by setting the nail spacing and length to be independent by installing only the beam beam nail. Modeling and analyzing; Constructing the nail nail prior to tunnel excavation; Seonbo nail tunnel, characterized in that excavation after securing the self-independence only with sunbo nail on the Yeonam abnormal base consisting of the steps to completely free the excavation site per blast with only sunbo nail and freely construct according to the ease of work. The excavation method can be applied.

At this time, when drilling once, the horizontal perforation is drilled in two rows, and the first perforation 41 is radially inclined to half of the excavation fabric factory once to the permissible line of the tunnel and radially inwardly by the width of the perforation. When the second outer hole 42 is drilled to the excavation fabric factory by moving in parallel and then the horizontal outer hole is charged, the first outer hole charges the precision explosives in the entire drilling hole and the second outer hole is Only half of the mills from the core are charged with precision explosives.

In addition, when drilling the inner beam nail tunnel in the pit, one side of the U-shaped measuring instrument 130 is inserted into the empty beam hole when drilling the horizontal outer hole and the horizontal enlargement hole in addition to the hollow beam of the top end and the membrane face where the excavation is scheduled. By exposing the other side to the curtain surface, it is possible to visually check the position of the hollow beam and allow the blasting hole to be drilled.

Effects obtained by the present invention having the above characteristics are as follows.

Since the free surface of the pre-excavated pilot tunnel is utilized before the excavation of the main tunnel of the large section in the tunnel nail nail tunnel, the blasting of the core hole to secure the free surface can be omitted. 30) can reduce the amount of puncture by reducing the number of blast holes required as blasting. As a result, the reduction of the amount of loading using the pilot tunnel as a free surface, so that the maximum excavation effect can be obtained with the minimum amount of loading, and thus the economical construction effect can be seen.

In addition, in the out-of-gang and inside-inner-edge beam nail tunnels, the nail interval is adjusted so that the tunnel becomes independent only through the design of the nail beam, and the beam nail is installed first before blasting the excavation surface of the main tunnel to secure the independence time of the tunnel. Since the excavation site can be increased more than the conventional excavation site per blasting, it is also possible to excavate half section or shear surface for split excavation for stability when excavating in large cross section tunnel. It is economical.

At this time, in case of using the conventional blasting method, once the excavation length is increased, a large amount of excavation may occur. However, as the present invention, the excavation is performed once by arranging two times as long as the outer hole is inclined in two rows so as not to escape the excavation line. Even if the amount is larger than the conventional one, the amount of extraction is not increased.

In addition, when drilling the blast hole for drilling the inner nail nail tunnel, the U-shaped measuring device that can adjust the length in the longitudinal direction of the tunnel can be displayed in advance on the tunnel excavation surface to avoid the overlap of the hollow beam and the blast hole can be blasted.

Hereinafter, with reference to the accompanying drawings the present invention will be described in detail.

FIG. 1 is a cross-sectional view of a charge using an empty beam as a blasting hole in an inside nail nail tunnel, and FIG. 2 is a cross-sectional view of a charge not using an empty beam as a blasting hole in an inner beam nail tunnel. FIG. 3A Figure 3b is a cross-sectional view showing the excavation site increased more than the existing per blast in the inner beam and outboard nail nail tunnel, Figure 4 and Figure 5 is an enlarged cross-sectional view showing the AA and BB portion of Figure 1, respectively. 6 is an enlarged cross-sectional view of the hollow beam and the heat transfer hole in the tunnel nail nail tunnel, Figure 7a to 7e is a cross-sectional view showing a detailed form of the blast hole according to the invention, Figure 8 is an excavation surface Fig. 9 is a cross-sectional view showing a U-shaped measuring instrument for indicating the position of the hollow beam, Fig. 9 is an embodiment of the propane nail tunnel, and Figs. 10a to 10c are conceptual views of the propagation nail tunnel, Figs. 11a and 11b is an illustration showing the design numerical analysis of the underground tunnel prophet beam four days.

That is, Figure 11a is a 3D model for the numerical analysis of the construction stage of the underground nail nail tunnel, after the construction of the ground nail nail in the condition that the ground is TYPE-4, once the excavation site 6.0m to 5m 30m In addition, modeling when the excavation without additional support, Figure 11b is a graph of the distal end of the reference point in the second stage of construction step 11a of FIG.

The present invention relates to a blasting excavation that is an undeveloped part of the sunbo tunnel method (Korean Patent No. 10-0740200).

The Propagation Tunneling method involves digging nails out of the upper surface of the shaft and excavating them (hereinafter referred to as the 'Exterior Propagation Nail Tunnel') and through the pilot tunnel in the planned large-sized tunnel, and the propagating nails inside the tunnel There is a method of pre-installation toward the end face of the tunnel (hereinafter referred to as 'inner beam nail tunnel'). These two methods are collectively called the Pre-Nailed Tunnelling Method.

This method is to excavate and expand to the main tunnel after installing the nail nails in or out of the tunnel, and additionally add the lining by constructing shotcrete rock bolts, etc. according to the design.

The above-mentioned large cross-section tunnel is commonly referred to as a tunnel having a width source of more than three lanes of roads, and a four-lane road tunnel is generally referred to as a large cross-section tunnel.

As shown in FIG. 10A, a method of performing tunnel blasting using the hollow beam 30 according to the hollow beam installation in the hollow tunnel nail nail tunnel is shown in Table 1 as an example. Classify by type according to rock class and compare with rock class of existing 2nd tunnel.

Table 1. Jib types and excavation sites for tunnels according to rock class

RMR 100-81 80-61 60-41 40-21 20 or less Bedrock grade I Ⅱ Ⅲ Ⅳ Ⅴ Rock condition Very good Good usually Bad Very bad 2nd Road Tunnel Jibo TYPE One 2 3 4 5 Excavation site More than 3.5m 3.5m 2.0m 1.5m / 3.0m 1.2m / 1.2m Propane nail
4 lane road tunnel

Jibo TYPE One 2 3 4 5 Drilling site per blast 6.0m or more More than 3.0m 2.0m or more
More than 2.0m 1.5m or more
More than 1.5m 1.5m or more
More than 1.5m Propane nail
Construction range  90 ° or less 90 °
~ 100 ° or less 90 °
~ 100 ° or less 100 °
~ 120 ° or less 120 °
~ 180 ° or less

As shown in FIG. 1, in constructing the inner beam nail nail tunnel, a horizontal edge is further added to the hollow beam 30 of the top end portion created while constructing the nail beam nail in the pilot tunnel and the membrane face to be excavated. After drilling the combination of the hole 40, the horizontal expansion hole 50 and the horizontal bottom hole 60, and then blasted by filling the above-mentioned hollow hole and the horizontal outer hole, horizontal enlargement hole, horizontal bottom hole.

In the pilot tunnel, the construction of the nail nails is necessary because the installation and grouting process of the nails should be carried out only to the excavation line of the main tunnel and the hollow beams should be formed. It is advantageous to minimize the construction of the nail beam nails in the range that the independence of the tunnel is secured by the structural analysis reinforced with only the nail beam nails.

Therefore, at this time, as shown in Table 1, the hollow hole for blasting is divided into TYPE-1 to 5 according to the independence of the ground, the angle between the hollow hole of the hollow of 90 ° or less or 90 ° to 180 ° range (32 Installed within the range of Soil independence is based on the classification of the soil into 5 grades according to the RMR (Bieniawski) classification, with RMR values of 100-81, 80-61, 60-41, 40-21, 20 or less. If the ground is bad as shown in TYPE-5 of Table 1, it should be constructed within the 180 ° range of the upper half section, and if the ground is somewhat stable like the TYPE-1, it should be 90 ° or less from the top of the top of the tunnel end. Install in the form of radial fan.

The charge of Seonbo Nail Tunnel is installed from the bottom to prevent the detonation of the primer so that the excavation length is constructed as long as possible. The intention is to minimize the occurrence of unexcavated parts generated during net explosion. In addition, if the expansion hole is detonated first, the beam bore 30 and the heat transfer hole may be damaged depending on the time difference and the position of the primer. Blasting in order of.

In the blasting by the above method, as shown in FIG. 6, when the length of excavation per blast is longer than in the related art, when the longitudinal spacing of the slotted boreholes that is uniformly arranged is larger than the color depth of the pilot tunnel, By drilling the heat-transfer hole 31 in the same direction in the front row of the bobbin ball, it is possible to control the violence during blasting.

As exemplified in Table 1 above, in the tunnel road of Sunjibo 4 lanes, the excavation length of the TYPE-2 is 3 m or more and the excavation length of the TYPE-3 is 2 m or more. TYPE-2 and 3 apply the blasting method using the empty beam, but in order to control the violence of gunpowder, the thermal bomb is placed in front of the empty beam as shown in FIG. In the addition of heat transfer holes, TYPE-2 drills two additional rows and TYPE-3 drills one additional row.

The effect can thus prevent the size of the blasted cancer block from growing too large and reduce the amount of violence acting on the ground around the reinforced tunnel.

As shown in FIGS. 6 and 7B, when charging explosives, the hollow hollow 30 fills the protective material 120 to protect the protruded hollow nail from the nail tip and color it directly below. The total length of the protective material and the full color is the minimum resistance of the horizontal perforated hole from the position of the main tunnel digging line of the hollow bore so that the horizontal perforated hole 40 and the horizontal enlarged hole 50 are not damaged even when the pre-empted hollow hole is pre-blasted. The length is separated by the length of the horizontal resistance hole plus the minimum resistance line. From this point, charge the explosives and color the hole. In this case, the heating hole is also drilled and charged so as to be spaced apart by the minimum resistance line distance and color. The dose is calculated and filled by the theoretical and empirical formulas for estimating the dose according to site conditions considering the resistance line and the clearance.

Like the sunbo hollow hole, the color of the uphole is to be used by using sand containing clay so as not to flow down. As the protective member 120, a buffer material such as polyethylene foam is used at the tip of the nail so that the previously constructed nail nail and grouting are not damaged.

In another embodiment, when the gunpowder is charged to blast as much as the above-mentioned excavation length in the inner tunnel nail nail tunnel, the blast hole perforated in the excavation direction is not charged with the explosives or explosives. You can only charge gunpowder or explosives. At this time, the empty beam is used as an armed drug because it does not charge, and the explosive charges or explosives are blasted in the order of horizontal expansion hole-horizontal outer hole-horizontal floor hole.

As shown in FIG. 3A and FIG. 3B, in the nail beam nail tunnel (inner beam nail beam or out-of-beam nail beam tunnel), workability is easier and the excavation length per blast is longer than before.

In the sun nail nail tunnel constructed as above, in order to facilitate the workability, lengthen the excavation length per blast, and simplify the membrane excavation, the base is designed to install only the nail nail nail in the good ground condition of soft rock or more. Modeling and analyzing excavation of one or more conventional membranes without adjusting the spacing and length per blast by adjusting intervals and lengths; Constructing the nail nail before the main tunnel excavation; Complete excavation of excavation site per blasting only with sunbeam nails and excavation after securing independence only with sunbeam nails on soft rock ore base consisting of blasting and excavating and constructing more than one conventional membrane according to design and ease of work. The excavation method of the shipboard nail tunnel is applied.

Conventionally, the work method that considers the importance of jibo is applied first, but the present invention is to consider the ease of work after securing the safety with the sun ji nail. Tunnel design analyzes the construction stage by multi-stage excavation of tunnel face, reinforced with shotcrete and rock bolt, and when the deformation of the surrounding ground converges, excavation of the next stage is completed to excavate in several stages. To complete the excavation. Multi-stage digging excavation refers to digging the membrane of a large cross section tunnel into a middle wall dividing, CD dividing line, sidewall robing, etc. The construction is most advantageous in the upper and lower half cross section tunnels, but it is difficult to apply in the past due to independence in large cross section tunnels.

The multi-stage split excavation is very cumbersome in construction and works in a state where the stability of the tunnel is unstable. After installation of shotcrete, rock bolt, and truss plate woven with reinforcing bars and steel bars, which are used in conventional tunneling tunnels at every time of excavation, after the deformation is converged by additional reinforcement of the tunnel base and supporting material, that is, after structural stability, To repeat.

However, the present invention is to excavate a large number of membranes by the upper and lower half-section or shear-face excavation method to simplify the membrane excavation only by the beam nails without the multi-stage digging excavation in the soft ground of soft rock or more, and then by designing and additionally supporting the additional support material When multi-stage split excavation, the shotcrete rock bolt process, which requires additional reinforcement in each step, can be omitted, and the excavation can be done freely.

However, where rockfall may occur locally, shotcrete may need to be constructed for each excavation site, and the amount of reinforced bownail reinforcement will be added.

When demonstrating an exemplary embodiment, if the conventional tunnel method is limited to one excavation site 3.5M in a two-lane road tunnel, the present invention is excavated up to 30m without additional information to 5m with one excavation site 6.0M in a four-lane large-section road tunnel Construction is possible.

As shown in FIG. 11A, the upper half-section excavation is performed when constructing the inner beam nail nail tunnel under ground condition (RMR IV grade) of TYPE-4 by modeling the inner beam nail nail tunnel in the four lane large section road tunnel. As a result of designing a tunnel with 6.0m at one tunnel and digging up to 30m without any additional support, the results were plotted for each construction stage based on the second end of the tunnel. As shown in FIG. 11B, it can be seen that convergence is completed at about 6.5 mm when the excavation is completed from the displacement measuring point to the posterior 3 membrane. After completing the construction of shotcrete and side wall rock bolt at once in the modeling 30m all-time zone, and the construction of the inner nail nail tunnel is completed, the final displacement of the top end of the tunnel converges at about 7.0mm.

Overall, as shown in Table 1, the excavation site is 3.5m once in TYPE-1, which has the best rock grade (RMR) in the existing existing two-way tunnel. Half-section excavation in tunnel One excavation site is 6.0m and excavation design is possible up to 5 curtains. The reason is that Seonbo Nail Tunnel is excavated in the state of nail propagation. This is because the constraint of ash drilling site is structurally less.

In addition, as shown in FIG. 3, the horizontal perforations are drilled in two rows at a predetermined lateral interval in the excavation surface 10 of the main ship tunnel in the wire beam nail tunnel (inner beam beam and out-of-beam beam tunnel). When the length of the excavation is increased once than the one excavation site 70 of the tunnel, the amount of excavation 80 generated can be reduced.

In order to reduce the overhang caused by the perforation angle of the perimeter of horizontal perforation, the perforation of the first perforation 41 is radially inclined to half of the excavation mill once outside the tunnel, and the parallel movement is performed by the width of the perforation allowed inward. The second outer hole 42 is drilled once to the excavation cloth factory. At this time, the first outer hole charges the precision explosives in the whole drilling hole so that the two outer holes do not interfere with each other, and the second outer hole charges the precision explosives from the core core to only half of the fabric factory and drills once. It is possible to increase the excavation length without increasing the amount of overhang.

In the inner beam nail nail tunnel, as shown in FIG. 8, the horizontal outer hole and horizontal enlargement hole are drilled in addition to the hollow beam of the top end portion created while constructing the nail beam nail in the pilot tunnel and the membrane face at which the excavation is scheduled. In order to prevent overlapping with the pre-installed line nails, one side of the U-shaped measuring instrument 130, which can be adjusted in the longitudinal direction of the tunnel, is inserted into the line beam hole, and the other side is exposed to the closed surface to position the line beam hole. Check visually and make the blast hole perforated. The U-shaped tube is divided into two L-shaped tubes divided into a fixed part and a measuring part, and can be used by separating or combining two times. Plug the two pins together to join the two L-shaped tubes.

By using the U-shaped measuring device 130, avoiding the overlapping of the empty beam empty hole and the blast hole to increase the blasting efficiency and improve the workability by accurately determining the position of the empty hole.

9 is a blasting design drawing of the inner nail nail tunnel of the large section tunnel, the firing sequence of the primer is first detonated by the hollow hole based on the pilot tunnel, and the horizontal expansion hole 50 is detonated stepwise toward the main tunnel excavation line. Next, the horizontal perforator is detonated and the horizontal bottom is detonated last, and the upper half section is blasted and excavated.

The lower part is detonated from the inner side to the outer side around the pilot tunnel, and blasts and excavates the lower half section in the order of the outer hole and the bottom hole.

1 is a cross-sectional view showing an embodiment of the blasting using a hollow beam as a blasting hole in the mine nail nail tunnel.

Figure 2 is a cross-sectional view showing an embodiment of the blasting not using a hollow beam as a blast hole in the tunnel nail nail tunnel.

Figure 3a is a cross-sectional view showing that the first perforated hole and the second perforated two rows so that the excavation rate is equal to twice as long as the excavation site per blasting in the out-of-ground preliminary nail tunnel.

Figure 3b is a cross-sectional view showing that the first perforated hole and the second perforated two rows so that the excavation amount is equal to twice as long as the excavation site per blasting in the mine tunnel nail tunnel.

Figure 4 is an enlarged cross-sectional view of the AA portion in FIG.

FIG. 5 is an enlarged cross-sectional view of a portion BB in FIG. 1; FIG.

Figure 6 is an enlarged cross-sectional view showing a hollow hole and a heat-transfer hole pre-punched in the mine tunnel nail tunnel.

Figure 7a to 7e is a cross-sectional view showing in detail the blast hole charge form according to the present invention.

8 is a cross-sectional view showing a U-shaped measuring instrument for indicating the position of the hollow beam hollow on the excavation surface.

9 is an embodiment of a sun nail nail tunnel.

10A and 10B are conceptual views of Sunbo nail tunnel.

10C is a conceptual diagram of an outboard mine nail tunnel;

Figures 11a and 11b is a figure showing the design numerical analysis of the intra-figure beam nail tunnel.

<Explanation of symbols for the main parts of the drawings>

10: main tunnel excavation surface 20: pilot tunnel

30: sun bore blank 31: electrician

32: empty beam between the hollows 33: nail nails

40: horizontal outer ball 41: first outer ball

42: second outside hole 50: horizontal expansion hole

60: horizontal bottom hole 65: upper and lower digging line border

70: conventional one drilling site 80: amount of excavation

90: Seonjibo empty space charge distance: 100:

110: full color 120: protective material

130: U-shaped measuring instrument 140: point width medicine

150: lock bolt 160: end displacement measurement position

Claims (12)

delete delete delete delete delete delete delete In the excavation method of the inside nail nail tunnel, In the tunnel longitudinal direction, so that the hollow beams and the excavation of the top end created during the construction of the beam nails in the pilot tunnel and the excavation are not overlapped with the beam beam nails pre-installed when drilling the horizontal outline hole and horizontal enlargement hole. One side of the U-shaped measuring instrument, whose length can be adjusted, is inserted into the hollow beam, and the other side is exposed to the curtain surface to visually confirm the position of the hollow beam by the U-shaped measuring instrument and to make the blast hole punctureable. Method of excavation of nail tunnels. The method of claim 8, The hollow beam for blasting is drilled in the form of radial scallops that form an angle of 90 ° to 180 ° in the transverse direction centering on the vertex of the end of the tunnel according to the independence of the ground. Excavation method. The method of claim 8, In order to prevent damage to the horizontal enlargement hole, the horizontal outline hole and the nail nail, even if the hollow line hole is blasted, the charge of the hollow line hole is added to the minimum resistance line of the horizontal line hole and the minimum resistance line of the horizontal line hole from the main tunnel digging line position. A method of excavating a nail nail tunnel, wherein the nail is colored to a point spaced by a length, and the explosive is charged from this point. After securing the line independence at the excavation ground by line reinforcement at the base of the tunnel, the horizontal periphery installed on the excavation surface of the main line tunnel at a constant lateral spacing is outside to the permissible line of the tunnel to reduce the overload caused by the drilling inclination angle. Radially inclining the first outer hole to half of the first drilling mill, and drilling the second outer hole to the first mill by moving inwardly in parallel with the width of the overhang; When the horizontal outer hole is charged after the step, the first outer hole is to charge the explosives in the whole hole, and the second outer hole further comprises the step of charging the explosives up to half of the cloth mill from the bottom. Excavation method of sun nail nail tunnel to use. In claim 11, a method of securing line independence by line reinforcement in the tunnel base is to facilitate workability, lengthen excavation length per blast, and simplify the excavation of the membrane. Adjusting nail intervals and lengths to install only nails and modeling and analyzing excavations per one blast and modeling excavation of one or more conventional membranes without additional support; Constructing the nail nail prior to the final excavation; Completely excavating the excavation site per blasting with only the nail nails and blasting and excavating more than one conventional film in accordance with the ease of design and operation; The excavation method of Sunjibo nail tunnel, characterized in that the excavation after securing the line independence only in the base plate of soft rock over the soft rock.

Images