Support methods for dark tunnel construction

Abstract

The present invention discloses a support method for dark tunnel construction, which belongs to tunnel construction technology. The method comprises: S1, a jack is placed in a first frame, a second frame is inserted in the first frame, the output end of the jack is abutted against the first frame, and a base is welded on the second frame; S2, a rock layer is pre-cracked to form a tunnel, the rock layer is transported out of the tunnel, and the tunnel ground is leveled with an electric pick; S3, a concrete cushion is poured on both sides of the tunnel ground; S4, a support base is placed on the concrete cushion, and the support bases on both sides of the tunnel are placed one by one; S5, a first I-beam is inserted into the base, the first I-beam is connected and fixed to the second I-beam, the second I-beams corresponding to each other on both sides of the tunnel are connected and fixed, and a support plate is laid on the second I-beam; S6, the jack is started to raise the support plate to the top of the tunnel. The support method for dark tunnel construction provided by the present invention has almost no disturbance to the rock layer soil during the support process, can effectively prevent the falling of gravel, and improves the construction safety.

Description

Technical Field

[0001] The invention belongs to the technical field of tunnel construction, and in particular relates to a supporting method for dark-digging tunnel construction. Background Art

[0002] The underground excavation method is a tunnel construction method and is currently a commonly used method in tunnel construction. Its basic principle is to use underground excavation machinery to excavate tunnels without damaging the surface. Mining method and shield method are both underground excavation methods. Although the shallow underground excavation method of urban tunnels and underground engineering construction technology is relatively mature, due to the uncertainty of engineering hydrogeological conditions and the complexity of the construction environment, there are still many construction risks in the shallow underground excavation method of underground engineering construction.

[0003] In order to solve the problem of a project being threatened by mountain stream floods on both sides of the mountain during the flood season, a water dam was built in the middle gully on both sides of the mountain to discharge the mountain stream floods through the vertical shafts and drainage pipes on both sides of the project slope to the downstream municipal box culvert. After the vertical shaft is completed, horizontal tunnel excavation is required. Due to the unsatisfactory geological conditions of the rock formation, if the existing support scheme is adopted, it is necessary to drill holes vertically upward to construct anchor rods, which will cause great disturbance to the rock formation soil, and it is very easy for rocks and debris to fall off, posing a greater safety risk. Summary of the invention

[0004] In view of the deficiencies existing in the related art, the object of the present invention is to provide a support method for dark tunnel construction to solve the problems raised in the above-mentioned background technology.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] A support method for dark tunnel construction, comprising:

[0007] S1. Prefabricated support base: place the jack in the first frame, insert the second frame into the first frame, make the output end of the jack abut against the second frame, and weld the base on the second frame;

[0008] S2. Pre-splitting of rock strata: Pre-splitting of rock strata at a set depth to form a tunnel, and transporting the rock strata out of the tunnel. Draw two lines along the tunnel extension direction at a distance of 500 mm from the two side walls of the tunnel, and use an electric pick to level the tunnel ground between the two lines;

[0009] S3. Pouring cushion layer: Starting from the edge of the tunnel entrance, pour a 100mm thick concrete cushion layer on both sides of the tunnel ground. The poured concrete cushion layer shall not exceed the two drawn lines, and the pouring shall be stopped at 1000mm from the deepest point of the tunnel;

[0010] S4. Place the support base: starting from the edge of the tunnel entrance, place the support bases on the concrete cushion layer at a first set distance, and place the support bases on both sides of the tunnel one by one. Use expansion bolts to connect and fix the first frame to the concrete cushion layer.

[0011] S5. Install the support plate: insert the first I-beam into the base and connect and fix it with the first connector. Use the second connector to connect and fix the second I-beam at the end of the first I-beam away from the base. Use the third connector to connect and fix the second I-beams corresponding to each other on both sides of the tunnel. Lay the installation support plate on the second I-beams.

[0012] S6. Jacking operation: Anchor bolts are used to anchor into the tunnel side walls at the second set distance on both sides of the first I-beam to limit the horizontal displacement of the first I-beam, and then the jack is started to perform jacking operation to raise the support plate to the top of the tunnel.

[0013] In some of the embodiments, the support method for dark tunnel construction further includes step S7: repeating steps S2 to S6 until the support work of the dark tunnel required for the support length is completed.

[0014] In some of the embodiments, the support method for dark tunnel construction also includes step S8: starting from the deepest part of the tunnel, installing a drainage steel pipe of a set length, and then removing the support plate, the second I-beam, the first I-beam and the support base within the set length in turn, and finally pouring concrete in the tunnel of the set length.

[0015] In some embodiments, in step S1, multiple support bases need to be prefabricated. Assuming the number of prefabricated support bases is N, then N=L÷l a ×2+2, where L is the support length, l a Set the distance for the first time.

[0016] In some of the embodiments, in step S1, two stiffening angle steels are welded on each side of the first frame, and the two stiffening angle steels are cross-arranged, and a steel plate is welded on the top of the second frame.

[0017] In some of the embodiments, in step S2, the set depth of the pre-splitting rock formation is 1600 mm to 1800 mm.

[0018] In some of the embodiments, in step S5, the supporting plate is a plywood with a thickness of 15 mm. First, the steel keel is welded and fixed to the second I-beam, holes are drilled at set positions of the plywood, and then galvanized iron wire is passed through the holes to connect and fix the plywood to the steel keel.

[0019] In some embodiments, in step S5, the first connecting member is an M20 high-strength bolt, and the second connecting member and the third connecting member are M30 high-strength bolts.

[0020] In some of the embodiments, in step S1, a jack of the same model with a load-bearing capacity of 10 tons is selected.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] 1. The support method for dark tunnel construction provided by the present invention can complete the support in a short time, has high support construction efficiency, and has almost no disturbance to the rock layer soil during the support process, which can effectively prevent the falling of gravel and improve the construction safety.

[0023] 2. The support method for dark tunnel construction provided by the present invention uses steel materials for support construction, which has high strength and good corrosion resistance. After the support construction is completed, it can be recycled or used in the next support construction, reducing the construction cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of this application. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0025] Figure 1 A flow chart of supporting steps of an embodiment of a supporting method for dark tunnel construction of the present invention;

[0026] Figure 2 A schematic front view of a support base structure of an embodiment of a support method for dark tunnel construction of the present invention;

[0027] Figure 3 A schematic side view of a support base structure of an embodiment of a support method for dark tunnel construction of the present invention;

[0028] Figure 4 A schematic top view of a support base structure of an embodiment of a support method for dark tunnel construction of the present invention;

[0029] Figure 5 A schematic diagram of a jack-up for one embodiment of a supporting method for dark tunnel construction according to the present invention;

[0030] Figure 6 A schematic diagram of an anchor bolt being anchored into a tunnel side wall according to an embodiment of a supporting method for dark-excavation tunnel construction of the present invention;

[0031] Figure 7 A schematic diagram of the connection between the first I-beam, the second I-beam and the support plate of an embodiment of the support method for dark tunnel construction of the present invention;

[0032] Figure 8 A schematic diagram showing the completion of the jacking operation of an embodiment of the support method for dark tunnel construction of the present invention;

[0033] Fig. 9 This is a schematic diagram of an embodiment of a support method for dark tunnel construction according to the present invention after construction of a certain support length.

[0034] In the figure:

[0035] 1. Support base; 11. Jack; 12. First frame; 121. Reinforcing angle steel; 13. Second frame; 131. Steel plate; 14. Base; 2. Rock layer; 3. Tunnel; 4. Concrete cushion; 5. Expansion bolt; 6. First I-beam; 61. First connecting piece; 7. Second I-beam; 71. Second connecting piece; 72. Third connecting piece; 8. Support plate; 9. Anchor bolt; 10. Steel keel. DETAILED DESCRIPTION

[0036] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0037] In the description of the present invention, it should be understood that the terms "center", "lateral", "longitudinal", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0038] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0039] See attached Figures 1 to 9 , an illustrative embodiment of the support method for dark-digging tunnel construction proposed by the present invention is given, and the support method for dark-digging tunnel construction comprises the following steps:

[0040] S1, prefabricated support base 1: place the jack 11 in the first frame 12, insert the second frame 13 in the first frame 12, make the output end of the jack 11 abut against the second frame 13, and weld the base 14 on the second frame 13;

[0041] S2, pre-splitting the rock layer 2: pre-splitting the rock layer 2 at a set depth to form a tunnel 3, and transporting the rock layer 2 out of the tunnel 3, drawing two lines along the extension direction of the tunnel 3 at a distance of 500 mm from the two side walls of the tunnel 3, and leveling the tunnel ground between the two lines with an electric pick;

[0042] S3, pouring cushion layer: starting from the edge of the tunnel entrance, pouring a 100mm thick concrete cushion layer 4 on both sides of the tunnel ground, the poured concrete cushion layer 4 does not exceed the two drawn lines. In this embodiment, the width of the concrete cushion layer 4 is 500mm, and the pouring is stopped at 1000mm from the deepest point of the tunnel 3 to reserve operating space for the next pre-splitting work of the rock layer 2;

[0043] S4, placing the support base 1: starting from the edge of the tunnel entrance, the support bases 1 are placed on the concrete cushion layer 4 at a first set distance, and the support bases 1 on both sides of the tunnel 3 are placed one by one, and the first frame 12 is connected and fixed to the concrete cushion layer 4 using expansion bolts 5;

[0044] S5. Install the support plate 8: insert the first I-beam 6 into the base 14 and connect and fix it with the first connecting piece 61; use the second connecting piece 71 to connect and fix the second I-beam 7 at the end of the first I-beam 6 away from the base 14; use the third connecting piece 72 to connect and fix the second I-beam 7 on both sides of the tunnel 3 that correspond to each other; and lay the support plate 8 on the second I-beam 7;

[0045] S6, jacking operation: anchor bolts 9 are used to anchor into the tunnel side wall at a second set distance on both sides of the first I-beam 6 to limit the horizontal displacement of the first I-beam 6, and then the jacks 11 are started to perform jacking operations to raise the support plate 8 to the top of the tunnel.

[0046] In order to ensure the stability and safety of the dark tunnel construction, segmented construction is required. The dark tunnel construction support method provided in this embodiment also includes step S7: repeating steps S2 to S6 until the support work of the required support length of the dark tunnel is completed. Through segmented construction, the disturbance to the rock layer and soil can be minimized.

[0047] In order to recycle steel and save costs, the support method for dark tunnel construction provided in this embodiment also includes step S8: starting from the deepest part of the tunnel 3, installing a set length of drainage steel pipe, and then sequentially removing the support plate 8, the second I-beam 7, the first I-beam 6 and the support base 1 within the set length, and finally pouring concrete in the set length of the tunnel 3. Specifically, after completing the support work of the required support length of the dark tunnel, at this time, the deepest part of the tunnel 3 is connected to the vertical shaft, and the drainage steel pipe is installed, and then the support removal operation is carried out, starting from the deepest part of the tunnel 3 and gradually dismantling from the inside to the outside, following the principle of first erection and then dismantling, and then erection and first dismantling, the support plate 8, the second I-beam 7, the first I-beam 6 and the support base 1 to be removed in sequence are transported out of the tunnel 3, and then concrete is poured on the outside of the drainage steel pipe to fill the tunnel 3 with concrete, and the pouring of concrete also needs to start from the deep part of the tunnel 3. The support removal operation should be gradually removed according to the order of concrete pouring, and premature removal or transitional removal is prohibited. The second I-beam 7, the first I-beam 6 and the support base 1 can be recycled or used in the next support construction under similar construction conditions, thereby reducing construction costs.

[0048] In order to speed up the construction progress and shorten the construction period, in this embodiment, in step S1, a plurality of support bases 1 need to be prefabricated. Assuming the number of prefabricated support bases 1 is N, then N=L÷l a ×2+2, where L is the support length, l a The first set distance is taken into consideration. a The support base 1 is set at an interval of 750mm to provide sufficient working space for the staff while ensuring the safety of the working area.

[0049] In this embodiment, the first frame 12 and the second frame 13 are two cubic frames, wherein the size of the first frame 12 is 500mm*500mm*500mm, and the size of the second frame 13 is 490mm*490mm*490mm. During the lifting operation, the jack 11 applies lifting pressure to the second frame 13, so that the second frame 13 starts to lift upward. The arrangement of the first frame 12 and the second frame 13 can, on the one hand, transmit the lifting force upward, and on the other hand, ensure that the jack 11 does not shake during the lifting process, and maintains vertical lifting during the lifting process.

[0050] In this embodiment, in step S1, the same type of jacks 11 with a bearing capacity of 10 tons are selected. During the lifting process, the jacks 11 in the same support section need to be lifted at the same time to ensure that the second I-beams 7 connected to each other at the top do not deviate during the lifting process.

[0051] In order to improve the rigidity and bearing capacity of the first frame 12 and the second frame 13, in this embodiment, in step S1, two stiffening angle steels 121 are welded on each side of the first frame 12, and the two stiffening angle steels 121 are arranged crosswise, and a steel plate 131 is welded on the top of the second frame 13 to cope with the eccentric force generated during the jacking process. Among them, the size of the steel plate 131 can be set according to actual needs. Since the steel plate 131 is welded on the top of the second frame 13, it does not affect the insertion of the second frame 13 into the first frame 12, and does not affect the jacking of the second frame 13 by the jack 11.

[0052] In step S2, the depth of the pre-splitting rock layer 2 is set to 1600mm-1800mm, so that a set of support bases 1 can be symmetrically installed and an operating space can be reserved for the next pre-splitting of the rock layer 2. Specifically, a water-grinding drill, a YT-28 hand pneumatic drill and a hydraulic pre-splitting device are selected to cooperate to complete the pre-splitting of the rock layer, and the single pre-splitting depth is 600mm-800mm. After 2-3 pre-splittings, a tunnel 3 with a depth of 1600mm-1800mm is formed.

[0053] In step S5, the support plate 8 is a plywood with a thickness of 15 mm, and the length and width of the plywood are processed according to the size of the tunnel 3. First, the steel keel 10 is welded and fixed on the second I-beam 7. The steel keel 10 uses A16@600 steel bars. Holes are drilled at the set position of the plywood, and then galvanized iron wire is passed through the holes to connect and fix the plywood and the steel keel 10. Among them, the galvanized iron wire uses galvanized iron wire of 10# and above. The galvanizing treatment increases the hardness and strength of the iron wire, making it more durable and reliable.

[0054] In step S5, the first connecting member 61 is an M20 high-strength bolt, and the second connecting member 71 and the third connecting member 72 are M30 high-strength bolts. The diameter of the M20 high-strength bolt is 20 mm, and the diameter of the M30 high-strength bolt is 30 mm. Both the M20 high-strength bolt and the M30 high-strength bolt are high-strength bolts, have similar strength grades and mechanical properties, can withstand high loads and dynamic loads, and ensure the stability and safety of the structure.

[0055] In the above exemplary embodiment, the support method for dark tunnel construction can complete the support in a short time, with high support construction efficiency, almost no disturbance to the rock layer soil during the support process, which can effectively prevent the falling of gravel and improve the construction safety. In addition, the materials used in the support construction are all steel, which has high strength and good corrosion resistance. After the support construction is completed, it can be recycled or used in the next support construction, reducing the construction cost.

[0056] Finally, it should be noted that: the various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0057] The above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, ordinary technicians in the field should understand that the specific implementation methods of the present invention can still be modified or some technical features can be replaced by equivalents without departing from the spirit of the technical solution of the present invention, which should be included in the scope of the technical solution for protection of the present invention.

Claims

1. A support method for dark tunnel construction, characterized in that: include: S1. Prefabricated support base: Make a first frame and a second frame, the first frame and the second frame are cubic frames, wherein the size of the first frame is larger than the second frame, place the jack in the first frame, insert the second frame in the first frame, make the output end of the jack abut against the second frame, and weld the base on the second frame; S2. Pre-splitting of rock strata: Pre-splitting of rock strata at a set depth to form a tunnel, and transporting the rock strata out of the tunnel. Draw two lines along the tunnel extension direction at a distance of 500 mm from the two side walls of the tunnel, and use an electric pick to level the tunnel ground between the two lines; S3. Pouring cushion layer: Starting from the edge of the tunnel entrance, pour a 100mm thick concrete cushion layer on both sides of the tunnel ground. The poured concrete cushion layer shall not exceed the two drawn lines, and the pouring shall be stopped at 1000mm from the deepest point of the tunnel; S4. Place the support base: starting from the edge of the tunnel entrance, place the support bases on the concrete cushion layer at a first set distance, and place the support bases on both sides of the tunnel one by one. Use expansion bolts to connect and fix the first frame to the concrete cushion layer. S5. Install the support plate: insert the first I-beam into the base and connect and fix it with the first connector. Use the second connector to connect and fix the second I-beam at the end of the first I-beam away from the base. Use the third connector to connect and fix the second I-beams corresponding to each other on both sides of the tunnel. Lay the installation support plate on the second I-beams. S6. Jacking operation: Anchor bolts are used to anchor into the tunnel side walls at the second set distance on both sides of the first I-beam to limit the horizontal displacement of the first I-beam, and then the jack is started to perform jacking operation to raise the support plate to the top of the tunnel.

2. The support method for dark tunnel construction according to claim 1, characterized in that: The method further includes step S7: repeating steps S2 to S6 until the support work of the required support length of the dark excavated tunnel is completed.

3. The support method for dark tunnel construction according to claim 2, characterized in that: It also includes step S8: starting from the deepest part of the tunnel, installing a drainage steel pipe of a set length, then removing the support plate, the second I-beam, the first I-beam and the support base within the set length in turn, and finally pouring concrete in the tunnel of the set length.

4. The support method for dark tunnel construction according to claim 1, characterized in that: In step S1, multiple support bases need to be prefabricated. Assuming the number of prefabricated support bases is N, then N=L÷l a ×2+2, where L is the support length, l a Set the distance for the first time.

5. The support method for dark tunnel construction according to claim 1, characterized in that: In step S1, two reinforcing angle steels are welded on each side of the first frame, and the two reinforcing angle steels are cross-arranged, and a steel plate is welded on the top of the second frame.

6. The support method for dark tunnel construction according to claim 1, characterized in that: In step S2, the set depth of the pre-splitting rock formation is 1600 mm to 1800 mm.

7. The support method for dark tunnel construction according to claim 1, characterized in that: In step S5, the supporting plate is a plywood with a thickness of 15 mm. First, the steel keel is welded and fixed on the second I-beam, holes are drilled at set positions of the plywood, and then galvanized iron wire is passed through the holes to connect and fix the plywood and the steel keel.

8. The support method for dark tunnel construction according to claim 1, characterized in that: In step S5, the first connecting member is an M20 high-strength bolt, and the second connecting member and the third connecting member are M30 high-strength bolts.

9. The support method for dark tunnel construction according to any one of claims 1 to 8, characterized in that: In step S1, a jack of the same model with a load-bearing capacity of 10 tons is selected.

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