Large-section hard rock tunnel slotting structure and method

Abstract

The invention belongs to the technical field of traffic tunnel engineering, and discloses a large-section hard rock tunnel slotting structure and method.A left slotting hole set, a right slotting hole set, an upper slotting hole set and a next slotting hole set are formed in a tunnel face in a drilling mode, all the slotting hole sets form a triangular prism groove cavity structure, the second lower slotting hole set is arranged above the next slotting hole set, and after blasting, the upper slotting hole set and the lower slotting hole set form a triangular prism groove cavity structure; and the front rock mass between the next slotting hole group and the lower second slotting hole group forms a crushed zone and loses supporting force, and the hard rock mass located above the crushed zone is prone to instability and inversion under the action force of the dead weight and the rock, so that full blasting forming of the slotting area is facilitated, and the operation efficiency is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of traffic tunnel engineering, and in particular relates to a large-section hard rock tunnel cutting structure and method. Background Art

[0002] At present, in the large-section hard rock tunnel excavation construction, since the saturated uniaxial compressive strength of such surrounding rock is at least above 30Mpa, only left and right oblique slot holes are arranged in the slot cavity, resulting in low excavation efficiency of drilling and blasting, small excavation footage, generally below 3.6m, which cannot meet the expected construction effect in engineering operations, delays the construction progress beyond the flow arrangement deadline, and reduces the construction speed.

[0003] In order to solve the problem that the excavation progress is affected by insufficient cutting efficiency in such large-section hard rock tunnels, we propose a large-section hard rock tunnel cutting structure and method. Summary of the invention

[0004] The object of the present invention is to provide a large-section hard rock tunnel slotting structure, slotting holes arranged on the tunnel face, the slotting holes comprising a left slotting hole group and a right slotting hole group arranged symmetrically along the tunnel center line, an upper slotting hole group, a lower second slotting hole group and a next slotting hole group arranged in sequence from top to bottom along the tunnel center line, the upper slotting hole group, the next slotting hole group and the lower second slotting hole group are all located between the left slotting hole group and the right slotting hole group.

[0005] Preferably, the left slot hole group and the right slot hole group have a plurality of left slot holes and right slot holes respectively arranged in the vertical direction, the drilling directions of the left slot holes and the right slot holes are respectively inclined to the center line of the tunnel, the upper slot hole group and the next slot hole group are respectively arranged in the direction perpendicular to the heading face, the upper slot hole group and the next slot hole group are respectively arranged in the horizontal direction, and the left slot hole group, the right slot hole group, the upper slot hole group and the next slot hole group are enclosed to form a triangular prism structure.

[0006] Preferably, the lower second slotting hole group is arranged along a direction perpendicular to the tunnel face, and the lower second slotting hole group is arranged with multiple lower second slotting holes in a horizontal direction, and the lower second slotting hole group is located on a side close to the next slotting hole group.

[0007] Preferably, the number of the left groove holes is 11, and the angle between the left groove holes and the tunnel face is 52°; the number of the right groove holes is 11, and the angle between the right groove holes and the tunnel face is 52°; the lengths of the left groove holes and the right groove holes are both 5060 mm, and the lengths of the left groove holes and the right groove holes perpendicular to the tunnel face are both 4000 mm.

[0008] Preferably, the upper slotted hole group is arranged with 5 upper slotted holes, the next slotted hole group is arranged with 5 next slotted holes, and the lower second slotted hole group is arranged with 4 lower second slotted holes. The upper slotted hole group, the next slotted hole group and the lower second slotted hole group are symmetrically arranged along the center line of the tunnel, and along the center line of the tunnel away from the center line of the tunnel, the length of the upper slotted hole gradually decreases, the length of the next slotted hole gradually decreases, and the length of the lower second slotted hole gradually decreases.

[0009] Preferably, in the projection of the next slot hole group and the next second slot hole group on the horizontal plane, the next slot holes and the next second slot holes are alternately and evenly arranged, and the lengths of the first slot holes and the second slot holes decrease successively from the tunnel centerline to the direction away from the tunnel centerline.

[0010] Preferably, the lengths of the upper groove hole are 1500mm, 2500mm, 3500mm, 2500mm and 1500mm from left to right; the lengths of the next groove hole are 1500mm, 2500mm, 3500mm, 2500mm and 1500mm from left to right; the lengths of the lower two groove holes are 1000mm, 2000mm, 2000mm and 1000mm from left to right.

[0011] Another object of the present invention is to provide a large-section hard rock tunnel cutting method, using the large-section hard rock tunnel cutting structure, comprising the following steps: S1. The faces on both sides of the tunnel centerline are symmetrically drilled to form a left slot hole group and a right slot hole group, and the drilling directions of the left slot holes and the right slot holes are inclined toward the tunnel centerline respectively; S2. Drill holes at the upper part of the tunnel centerline in a direction perpendicular to the tunnel face to form an upper slot hole group, and drill holes at the lower part of the tunnel centerline in a direction perpendicular to the tunnel face to form a lower slot hole group; S3. Drilling holes between the upper slot hole group and the next slot hole group in a direction perpendicular to the tunnel face to form the lower second slot hole group; S4. After the blasting of each slot hole, a left broken crack is formed at the left slot hole group, a right broken crack is formed at the right slot hole group, an upper broken crack is formed at the upper slot hole group, a lower broken crack is formed at the next slot hole group, and a lower second broken crack is formed at the lower second slot hole group. The left broken crack, the right broken crack, the upper broken crack and the next broken crack form a triangular prism-shaped slot cavity structure. The front rock mass between the next broken crack and the lower second broken crack forms a broken zone and loses its supporting force. The rock blocks in the slot cavity flip and collapse under the action of their own weight, and the expected slotting effect can be achieved.

[0012] Preferably, the blasting sequence in step S4 includes: In the first step, the left and right slot hole groups are blasted; The second step is blasting the upper slot hole group; The third step is to blast the first and second slot hole groups.

[0013] The present invention has the following beneficial effects: The present invention provides a large-section hard rock tunnel slotting structure and method. Slotting holes are arranged on the heading face. A left slotting hole group, a right slotting hole group, an upper slotting hole group and a lower slotting hole group are combined to form a triangular prism slot structure. The lower second slotting hole group is arranged above the lower slotting hole group. First, the left slotting hole group is blasted to form a left broken crack, the right slotting hole group is blasted to form a right broken crack, then the upper slotting hole group is blasted to form an upper broken crack, and finally the lower slotting hole group and the lower second slotting hole group are blasted to form a lower broken crack and a lower second broken crack, and the front rock mass between the lower broken crack and the lower second broken crack forms a broken zone and loses its supporting force. The hard rock mass above the broken zone is easily unstable and reversed under its own weight and the force between rocks, which is conducive to the full blasting and forming of the slotting area. The excavation footage of the large-section hard rock tunnel slotting structure of the present invention can reach 4m, which is helpful to improve the excavation efficiency of the large-section tunnel. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a schematic diagram of the large-section hard rock tunnel cutting structure in the present invention.

[0015] Figure 2 It is a structural schematic diagram of the left slot hole group and the right slot hole group arranged on the tunnel face in the present invention.

[0016] Figure 3 yes Figure 2 Schematic diagram of the top view of the left and right slot hole groups in the middle.

[0017] Figure 4 It is a structural schematic diagram of the left slot hole group, the right slot hole group and the upper slot hole group arranged on the tunnel face in the present invention.

[0018] Figure 5 yes Figure 4 Schematic diagram of the top view of the middle left slot hole group, the right slot hole group and the upper slot hole group.

[0019] Figure 6 It is a structural schematic diagram of the left slot hole group, the right slot hole group, the next slot hole group and the next second slot hole group arranged on the tunnel face in the present invention.

[0020] Figure 7 yes Figure 6 Schematic diagram of the top view of the middle left slot hole group, the right slot hole group, the next slot hole group and the next second slot hole group.

[0021] Figure 8 It is a structural schematic diagram of a groove cavity formed by enclosing a left breaking crack, a right breaking crack, an upper breaking crack and a lower breaking crack in the present invention.

[0022] Fig. 9 It is a side view structural schematic diagram of the upper breaking crack, the lower breaking crack and the lower second breaking crack in the present invention located in the groove cavity.

[0023] In the figure: 1. Tunnel excavation contour line; 2. Tunnel bottom contour line; 3. Tunnel center line; 4. Heading face; 5. Left slot hole group; 51. Left slot hole; 52. Left broken crack; 6. Right slot hole group; 61. Right slot hole; 62. Right broken crack; 7. Upper slot hole group; 71. Upper slot hole; 72. Upper broken crack; 8. Lower slot hole group; 81. Lower slot hole; 82. Lower broken crack; 9. Lower second slot hole group; 91. Lower second slot hole; 92. Lower second broken crack; 10. Broken zone. DETAILED DESCRIPTION

[0024] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0025] A large-section hard rock tunnel cutting structure and method, Reference Figure 1 and Figure 8 The present invention proposes a large-section hard rock tunnel slotting structure, wherein a tunnel excavation contour line 1 and a tunnel bottom contour line 2 enclose a tunnel excavation face contour, namely, a tunnel face 4, and a left slot hole group 5 and a right slot hole group 6 are symmetrically arranged on the left and right sides of a center line of the tunnel excavation contour line (hereinafter referred to as the tunnel center line 3), and the left slot hole group 5 and the right slot hole group 6 are both distributed vertically, and an upper slot hole group 7 is arranged horizontally at the upper part of the tunnel center line 3, and a lower slot hole group 8 and a lower second slot hole group 6 are arranged at intervals at the lower part of the tunnel center line 3. Group 7, wherein the lower two slot hole groups 7 are located between the next slot hole group 8 and the upper slot hole group 7, the left slot hole group 5 and the right slot hole group 6 cooperate to form a wedge-shaped structure, the upper slot hole group 7, the next slot hole group 8 and the lower two slot hole groups 9 are located between the left slot hole group 5 and the right slot hole group 6, the upper slot hole group 7, the next slot hole group 8 and the lower two slot hole groups 9 are drilled along the direction perpendicular to the tunnel face 4 respectively, and the left slot hole group 5, the right slot hole group 6, the upper slot hole group 7 and the lower slot hole group 8 enclose a slot cavity with a structure similar to a triangular prism.

[0026] The height position of the upper groove hole group 7, the height position of the left groove hole 51 at the top in the left groove hole group 5, and the height position of the right groove hole 61 at the top in the right groove hole group 6 are the same; the height position of the next groove hole group 8, the height position of the left groove hole 51 at the bottom in the left groove hole group 5, and the height position of the right groove hole 61 at the bottom in the right groove hole group 6 are the same.

[0027] The vertical distance between the intersection of the tunnel vault and the tunnel centerline 3 and the tunnel bottom contour line 2 is 9300 mm, and the length of the tunnel bottom contour line 2 is 1200 mm.

[0028] Reference Figure 2 and Figure 3 The left slot hole group 5 includes 11 left slot holes 51 distributed at intervals along the vertical direction. The distance between the starting position of the left slot hole 51 and the center line 3 of the tunnel is 3200 mm, the distance between the ending position of the left slot hole 51 and the center line 3 of the tunnel is 200 mm, the angle β between the channel of the left slot hole 51 and the tunnel face 4 is 52°, the length of the left slot hole 51 is 5060 mm, and the left slot hole 51 is drilled in the horizontal plane from the starting position to the ending position. As the drilling depth of the left slot hole 51 gradually increases, the end of the channel gradually approaches the center line 3 of the tunnel, that is, the drilling direction of the channel of the left slot hole 51 is inclined toward the center line 3 of the tunnel.

[0029] The right slot hole group 6 includes 11 right slot holes 61 distributed at intervals along the vertical direction. The distance between the starting position of the right slot hole and the center line 3 of the tunnel is 3200 mm, the distance between the ending position of the right slot hole 61 and the center line 3 of the tunnel is 200 mm, the angle β between the channel of the right slot hole 61 and the tunnel face 4 is 52°, the length of the right slot hole 61 is 5060 mm, and the right slot hole 61 is drilled in the horizontal plane from the starting position to the ending position. As the drilling depth of the right slot hole 61 gradually increases, the end of the channel gradually approaches the center line 3 of the tunnel, that is, the drilling direction of the channel of the right slot hole 61 is inclined toward the center line 3 of the tunnel.

[0030] The vertical lengths of the left cut hole 51 and the right cut hole 61 perpendicular to the tunnel face 4 are both 4000 mm, that is, the depth of each tunnel excavation is 4000 mm.

[0031] Reference Figure 4 and Figure 5The upper groove hole group 7 includes 5 upper groove holes 71. The distance between the upper groove hole group 7 and the tunnel bottom contour line 2 is 5800 mm. The upper groove hole group 7 is symmetrically distributed along the tunnel center line 3. The upper groove hole group 7 includes a first upper groove hole 711, a second upper groove hole 712, a third upper groove hole 713, a fourth upper groove hole 714 and a fifth upper groove hole 715 arranged in sequence. The distance between adjacent upper groove holes 71 is 400 mm. Among them, the third upper groove hole 713 is located at On the tunnel centerline 3, the first upper groove hole 711 and the fifth upper groove hole 715 are symmetrically positioned and have the same length, the second upper groove hole 712 and the fourth upper groove hole 714 are symmetrically positioned and have the same length, and the length gradually decreases from the third upper groove hole 713 to the first upper groove hole 711. Specifically, the length of the third upper groove hole 713 is 3500 mm, the length of the second upper groove hole 712 is 2500 mm, and the length of the first upper groove hole 711 is 1500 mm.

[0032] Reference Figure 6 and Figure 7 The next slot hole group 8 includes 5 next slot holes 81. The distance between the next slot hole group 8 and the tunnel bottom contour line 2 is 400 mm. The next slot hole group 8 is symmetrically distributed along the tunnel center line 3. The next slot hole group 8 includes a first next slot hole 811, a second next slot hole 812, a third next slot hole 813, a fourth next slot hole 814 and a fifth next slot hole 815 which are evenly spaced and arranged in sequence. The distance between adjacent next slot holes 81 is 400 mm. 13 is located on the tunnel centerline 3, the first next groove hole 811 and the fifth next groove hole 812 are symmetrically positioned and have the same length, the second next groove hole 812 and the fourth next groove hole 814 are symmetrically positioned and have the same length, and the length of the third next groove hole 813 gradually decreases to the length of the first next groove hole 811. Specifically, the length of the third next groove hole 813 is 3500 mm, the length of the second next groove hole 812 is 2500 mm, and the length of the first next groove hole 811 is 1500 mm.

[0033] The lower second groove hole group 9 includes 4 lower second groove holes 91, and the distance between the lower second groove hole group 9 and the lower contour line 2 of the tunnel is 1200mm. The lower second groove hole group 9 is symmetrically distributed along the center line 3 of the tunnel. The lower second groove hole group 9 includes the first lower second groove hole 911, the second lower second groove hole 912, the third lower second groove hole 913 and the fourth lower second groove hole 914 that are evenly spaced and arranged in sequence. The distance between adjacent lower second groove holes 91 is 400mm, the first lower second groove hole 911 and the fourth lower second groove hole 914 are symmetrical in position and have the same length, the second lower second groove hole 912 and the third lower second groove hole 913 are symmetrical in position and have the same length, and the length of the second lower second groove hole 912 is greater than that of the first lower second groove hole 911. Specifically, the length of the second lower second groove hole 912 is 2000mm, and the length of the first lower second groove hole 911 is 1000mm.

[0034] As a preferred embodiment, the lower two groove hole groups 9 and the next groove hole group 8 are evenly and alternately distributed on the projection of the tunnel bottom surface, and the lengths of the next groove hole 81 and the lower two groove holes 91 decrease successively along the tunnel centerline 3 away from the tunnel centerline 3.

[0035] The present invention also provides a large-section hard rock tunnel cutting method, which adopts the large-section hard rock tunnel cutting structure and specifically comprises the following steps: S1, drilling holes on both sides of the tunnel centerline 3 on the tunnel face 4 to form a left slot hole group 5 and a right slot hole group 6, and the drilling directions of the left slot hole 51 and the right slot hole 61 are inclined toward the tunnel centerline respectively; S2, drilling holes at the upper face 4 of the tunnel centerline 3 to form an upper slot hole group 7, drilling holes at the lower part of the tunnel centerline 3 to form a lower slot hole group 8, the upper slot hole 71 and the lower slot hole are drilled in a direction perpendicular to the face 4, and the upper slot hole group 7 and the lower slot hole group 8 are symmetrical along the tunnel centerline 3; S3, drilling holes between the upper slot hole group 7 and the lower slot hole group 8 to form a lower second slot hole group 9, the lower second slot hole group 9 is drilled in a direction perpendicular to the tunnel face 4, and the lower second slot hole group 9 is symmetrical along the tunnel centerline 3; S4. After the above-mentioned slot holes are blasted, a left broken crack 52 is formed at the position of the left slot hole group 5, a right broken crack 62 is formed at the position of the right slot hole group 6, an upper broken crack 72 is formed at the position of the upper slot hole group 7, a next broken crack 82 is formed at the position of the next slot hole group 8, and a second lower broken crack 92 is formed at the position of the second lower slot hole group 9. The left broken crack 52, the right broken crack 62, the upper broken crack 72 and the next broken crack 92 together form a slot cavity structure that is approximately a triangular prism.

[0036] Blasting sequence: Step 1, blasting the left slot hole group and the right slot hole group; Step 2, blasting the upper slot hole group; Step 3, blasting the lower slot hole group and the lower second slot hole group.

[0037] In the present invention, the upper crack 72 and the lower crack 82 are both long cut cracks, and the lower two cracks 92 are short cut cracks, wherein the long cut cracks cut through the groove area, and the short cut cracks do not cut through the groove area, forming a support point at the rear end of the bottom of the groove area (refer to Fig. 9 ), the front rock mass between the next broken crack 82 and the next second broken crack 92 forms a broken zone 10 and loses its supporting force. The grooved rock blocks (i.e., the rock blocks in the groove cavity) formed by the left broken crack 52, the right broken crack 62, the upper broken crack 72 and the next broken crack 82 turn over and collapse under the action of their own weight. The present invention is conducive to the full blasting formation of the grooved area.

[0038] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A large-section hard rock tunnel cutting structure, characterized in that: The slot holes are arranged on the tunnel face, and the slot holes include a left slot hole group and a right slot hole group which are arranged symmetrically along the tunnel center line, and an upper slot hole group, a lower second slot hole group and a next slot hole group which are arranged in sequence from top to bottom along the tunnel center line, and the upper slot hole group, the next slot hole group and the lower second slot hole group are all located between the left slot hole group and the right slot hole group.

2. The large-section hard rock tunnel cutting structure according to claim 1, characterized in that: The left slot hole group and the right slot hole group have a plurality of left slot holes and right slot holes respectively arranged vertically, and the hole drilling directions of the left slot holes and the right slot holes are respectively inclined to the center line of the tunnel, the upper slot hole group and the next slot hole group are respectively arranged in the direction vertical to the tunnel face, and the upper slot hole group and the next slot hole group are respectively arranged in the horizontal direction. The left slot hole group, the right slot hole group, the upper slot hole group and the next slot hole group are enclosed to form a triangular prism structure.

3. The large-section hard rock tunnel cutting structure according to claim 2, characterized in that: The lower second slotting hole group is arranged along the direction perpendicular to the tunnel face, and the lower second slotting hole group is arranged with multiple lower second slotting holes in the horizontal direction. The lower second slotting hole group is located on one side close to the next slotting hole group.

4. The large-section hard rock tunnel cutting structure according to claim 3, characterized in that: The number of the left groove holes is 11, and the angle between the left groove holes and the tunnel face is 52°. The number of the right groove holes is 11, and the angle between the right groove holes and the tunnel face is 52°. The lengths of the left groove holes and the right groove holes are both 5060 mm, and the lengths of the left groove holes and the right groove holes perpendicular to the tunnel face are both 4000 mm.

5. The large-section hard rock tunnel cutting structure according to claim 3, characterized in that: The upper slotted hole group is arranged with 5 upper slotted holes, the next slotted hole group is arranged with 5 next slotted holes, and the second lower slotted hole group is arranged with 4 second lower slotted holes. The upper slotted hole group, the next slotted hole group and the second lower slotted hole group are symmetrically arranged along the center line of the tunnel, and along the center line of the tunnel away from the center line of the tunnel, the length of the upper slotted hole gradually decreases, the length of the next slotted hole gradually decreases, and the length of the second lower slotted hole gradually decreases.

6. The large-section hard rock tunnel cutting structure according to claim 5, characterized in that: On the projection of the next slot hole group and the next second slot hole group on the horizontal plane, the next slot holes and the next second slot holes are alternately and evenly arranged, and the lengths of the first slot holes and the second slot holes decrease successively from the tunnel center line to the direction away from the tunnel center line.

7. The large-section hard rock tunnel cutting structure according to claim 6, characterized in that: The lengths of the upper groove holes are 1500mm, 2500mm, 3500mm, 2500mm and 1500mm from left to right; the lengths of the lower groove holes are 1500mm, 2500mm, 3500mm, 2500mm and 1500mm from left to right; the lengths of the lower two groove holes are 1000mm, 2000mm, 2000mm and 1000mm from left to right.

8. A large-section hard rock tunnel cutting method, using the large-section hard rock tunnel cutting structure according to any one of claims 1 to 7, characterized in that: The following steps are involved: S1. The faces on both sides of the tunnel centerline are symmetrically drilled to form a left slot hole group and a right slot hole group, and the drilling directions of the left slot holes and the right slot holes are inclined toward the tunnel centerline respectively; S2. Drill holes at the upper part of the tunnel centerline in a direction perpendicular to the tunnel face to form an upper slot hole group, and drill holes at the lower part of the tunnel centerline in a direction perpendicular to the tunnel face to form a lower slot hole group; S3. Drilling holes between the upper slot hole group and the next slot hole group in a direction perpendicular to the tunnel face to form the lower second slot hole group; S4. After the blasting of each slot hole, a left broken crack is formed at the left slot hole group, a right broken crack is formed at the right slot hole group, an upper broken crack is formed at the upper slot hole group, a lower broken crack is formed at the next slot hole group, and a lower second broken crack is formed at the lower second slot hole group. The left broken crack, the right broken crack, the upper broken crack and the lower broken crack together form a triangular prism-shaped slot cavity structure. The front rock mass between the lower broken crack and the lower second broken crack forms a broken zone and loses its supporting force. The rock blocks in the slot cavity overturn and collapse under the action of their own weight.

9. The large-section hard rock tunnel cutting method according to claim 8, characterized in that: The blasting sequence in step S4 includes: In the first step, the left and right slot hole groups are blasted; The second step is blasting the upper slot hole group; The third step is to blast the first and second slot hole groups.

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