Shallow-buried excavation tunnel deslagging method suitable for CRD construction method

Abstract

The invention discloses a shallow-buried excavation tunnel deslagging method suitable for a CRD construction method. The shallow-buried excavation tunnel deslagging method comprises the steps that 1, a construction platform flush with a temporary inverted arch is arranged at a tunnel portal; 2, a first pilot tunnel on the upper portion is excavated, and muck is conveyed out through a discharging opening formed in the construction platform; 3, after the first pilot tunnel is excavated to the first depth, the first tilting cart is used for backing up to transfer the muck to a discharging opening to be conveyed out; 4, a second pilot tunnel on the same side as the first pilot tunnel is excavated, and the muck is transferred out of the projection range of the construction platform through a second tilting cart; 5, after the first pilot tunnel is excavated to the second depth, a third pilot tunnel on the upper portion is excavated, and the muck is conveyed out according to the modes of the step 2 and the step 3; 6, a fourth pilot tunnel is excavated, and the muck is transported out according to the mode in the step 4; 7, when the first pilot tunnel is excavated to the third depth, a transverse channel is formed in the middle partition wall so that excavation equipment can pass through the transverse channel; and 8, along with advancing of the digging depth, transverse channels are additionally arranged at intervals.

Description

Technical Field

[0001] The present invention relates to the technical field of tunnel engineering construction, and in particular to a slag removal method for a shallow buried dark excavation tunnel suitable for a CRD construction method. Background Art

[0002] In the field of shallow-buried tunnel engineering, the CRD method (cross partition wall method) can divide large-section tunnels into multiple independent pilot tunnels for sequential excavation, effectively controlling ground deformation, thanks to its cross-support system formed by vertical partition walls and temporary transverse inverts. It has become a commonly used method for traversing complex geological conditions.

[0003] However, as excavation depth increases, this method faces significant efficiency bottlenecks in the removal of excavated material. Limited by the inherently confined space within the tunnel, traditional excavation often involves a double transfer between pilot tunnels, for example, lowering excavated material from the upper pilot tunnel into the lower pilot tunnel and subsequently transporting it out of the tunnel. This practice not only encroaches on the lower pilot tunnel's working surface, disrupting the process, but also requires repeated loading of all excavated material, hindering the efficient turnover of critical equipment such as excavators and transport vehicles. Furthermore, the cramped operating environment within the pilot tunnels prevents transport vehicles from turning around, and the physical separation of the central partition hinders the rapid transfer of equipment between the left and right pilot tunnels, requiring vehicles to perform U-turns and transfers on platforms outside the tunnel. As tunnel excavation depth continues to increase, the accumulated time cost of transporting equipment back and forth increases, significantly reducing construction efficiency. Furthermore, the dumping of excavated material at high drop heights, the spatial conflicts caused by intersecting operations, and the frequent movement of machinery all pose potential safety risks.

[0004] Therefore, how to break through the slag discharge efficiency barrier in the construction of multi-pilot tunnels using the CRD method and achieve efficient and coordinated excavation of pilot tunnels while ensuring safety has become a technical problem that needs to be solved urgently. Summary of the Invention

[0005] The main technical problem to be solved by the present invention is to provide a slag discharge method for shallow buried dark excavation tunnels suitable for the CRD method, so as to realize rapid slag discharge of multiple tunnels.

[0006] In order to solve the above technical problems, the present invention provides a method for removing slag from a shallow buried tunnel using a CRD method. The tunnel excavation face includes four pilot tunnels separated by vertical partition walls and horizontal temporary inverts. The method comprises the following steps:

[0007] Step 1: Setting up a construction platform at the tunnel entrance; the construction platform is flush with the temporary invert arch;

[0008] Step 2: excavating a first pilot tunnel to a first depth, wherein the first pilot tunnel is an upper pilot tunnel on either side; the excavated soil is transported out through a discharge port provided on the construction platform;

[0009] Step 3: After the first pilot tunnel is excavated to the first depth, in the subsequent excavation operation, a first dump truck is used to reverse into the first pilot tunnel and transfer the debris to the discharge port on the construction platform for transportation;

[0010] Step 4: Excavate a second pilot tunnel, which is a lower pilot tunnel on the same side as the first pilot tunnel; use a second dump truck to transfer the debris in the second pilot tunnel to outside the projection range of the construction platform;

[0011] Step 5: After the first pilot tunnel is excavated to the second depth, a third pilot tunnel is excavated; the third pilot tunnel is an upper pilot tunnel adjacent to the first pilot tunnel; the debris generated in the third pilot tunnel is removed in the same manner as in Steps 2 and 3;

[0012] Step 6: Excavate a fourth pilot tunnel, which is a lower pilot tunnel on the same side as the third pilot tunnel; remove the debris generated in the fourth pilot tunnel in the same manner as in Step 4;

[0013] Step 7: When the first pilot tunnel is excavated to the third depth, transverse passages are opened on the intermediate partition walls above and below the temporary invert to allow excavation equipment to pass through;

[0014] Step 8: As the excavation depth increases, the cross passages are added at intervals;

[0015] In steps 1 to 8, the debris transported out of the above-mentioned guide tunnels is finally lifted by lifting equipment and transferred to the debris pool.

[0016] In a preferred embodiment, cross beams and columns are provided on the periphery of the opening of the transverse passage opened on the middle partition wall; the cross beams are provided at the top of the transverse passage; the columns are provided on both sides of the transverse passage, the tops are welded to the cross beams, and the bottoms are supported on the temporary inverted arch.

[0017] In a preferred embodiment, the transverse channel is provided with diagonal braces on both sides of the top; the two ends of the diagonal braces are respectively welded to the crossbeam and the column.

[0018] In a preferred embodiment, the cross beam and / or the column are made of steel components.

[0019] In a preferred embodiment, the transverse passages are arranged at intervals of 40 to 50 meters.

[0020] In a preferred embodiment, a first hopper is provided below the discharge port on the construction platform; the debris produced in the first and third guide tunnels is transported out of the tunnel by the first dump truck and poured into the first hopper through the discharge port.

[0021] In a preferred embodiment, the second dump truck is provided with a second hopper; the debris produced by the second pilot tunnel and the fourth pilot tunnel is directly loaded into the second hopper and transported by the second dump truck to outside the projection range of the construction platform.

[0022] In a preferred embodiment, the width of the construction platform is not less than 5 meters, and the length extends to the side walls on both sides of the shaft at the tunnel entrance.

[0023] In a preferred embodiment, the hoisting equipment is a bridge crane.

[0024] In a preferred embodiment, the first depth is 4 to 8 meters from the tunnel entrance; the second depth is 10 to 20 meters from the tunnel entrance; and the third depth is 40 to 60 meters from the tunnel entrance.

[0025] Compared with the prior art, the technical solution of the present invention has the following beneficial effects:

[0026] The method provided by the present invention significantly reduces the ineffective transportation distance and waiting time of mechanical equipment through systematic optimization of the slag discharge process of the upper and lower pilot tunnels and the rational use of key facilities such as platforms and cross passages, greatly improving construction efficiency. Within the extremely limited constraints of underground space, this method achieves efficient utilization of site resources through scientific planning of process connections and orderly management of space, effectively avoiding the cross-interference and safety accident risks that may arise from the simultaneous construction of the upper and lower pilot tunnels, and providing reliable technical support for the safe and rapid construction of underground tunnels under complex geological conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 Schematic diagram of the cross section of each pilot tunnel and cross passage of the CRD construction method in an embodiment of the present invention;

[0028] Figure 2 Schematic top view of the slag discharge method according to an embodiment of the present invention;

[0029] Figure 3 Schematic diagram of the operation of each dump truck and hopper in the embodiment of the present invention;

[0030] Figure 4 It is a schematic elevation view of the transverse channel described in an embodiment of the present invention.

[0031] Markings in the figure are: 11-temporary inverted arch, 12-middle partition wall, 21-upper left guide tunnel, 22-lower left guide tunnel, 23-upper right guide tunnel, 24-lower right guide tunnel, 3-construction platform, 4-unloading port, 5-vertical shaft, 61-first hopper, 62-second hopper, 71-first dump truck, 72-second dump truck, 8-cross passage, 81-cross beam, 82-column, 83-diagonal brace. DETAILED DESCRIPTION

[0032] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention; it is obvious that the described embodiments are only part of the embodiments of the present invention, rather than all 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.

[0033] In the description of the present invention, it should be noted that the terms "upper," "lower," "inner," "outer," "top / bottom," and the like, indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings and are intended solely to facilitate and simplify the description of the present invention. They are not intended to indicate or imply that the devices or components referred to must have, be constructed, or operate in a specific orientation, and therefore should not be construed as limitations on the present invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0034] In the description of the present invention, it should be noted that, unless otherwise clearly stipulated and limited, the terms "installed", "provided with", "set / connected", "connected", etc. should be understood in a broad sense. For example, "connection" can be a wall-mounted connection, a detachable connection, or an integral connection. It can be a mechanical connection or an electrical connection. It can be a direct connection or an indirect connection through an intermediate medium. It can be the internal connection 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 the specific circumstances.

[0035] like Figure 1As shown in the figure, in this embodiment of the present invention, the pilot tunnels of the CRD method are arranged in a cross-sectional arrangement using vertical intermediate walls 12 and horizontal temporary inverts 11, dividing the elliptical tunnel cross-section into four independent pilot tunnel spaces of substantially equal size: an upper left pilot tunnel 21, an upper right pilot tunnel 23, a lower left pilot tunnel 22, and a lower right pilot tunnel 24. The upper left and upper right pilot tunnels 21 and 23 utilize the temporary inverts 11 as the road surface. The structural framework of these temporary inverts 11 and intermediate walls 12 is constructed from 120a I-beams arranged at 0.5-meter longitudinal intervals. The steel frames are connected with 22-mm-diameter longitudinal connecting bars and reinforced with steel mesh. Finally, a 350-mm-thick concrete lining is sprayed to form the initial lining. The steel frames of the temporary inverts 11 and intermediate walls 12 must be securely connected to the tunnel's initial support grid steel frame via bolts. Once the concrete is sprayed and solidifies, the entire structure forms a sturdy, closed, circumferential support system. For the construction of the lower left pilot tunnel 22 and the lower right pilot tunnel 24, a layer of excavated soil is first laid on the initial support structure of the tunnel as a foundation cushion layer, and then a layer of 20 cm thick concrete cushion layer is poured on top of it to form a stable working surface.

[0036] like Figures 1 to 4 As shown, based on the above-mentioned construction foundation, an embodiment of the present invention provides a slag discharge method for shallow buried tunnels suitable for the CRD method. By synergistically utilizing the additional transverse passage 8 inside the tunnel and the specially built steel structure construction platform 3 at the entrance, the turnover efficiency of excavation equipment, transportation equipment, etc. is improved to solve the problem of low slag discharge efficiency in traditional CRD construction.

[0037] The specific slag removal steps of the method include:

[0038] Step 1: If Figure 2 As shown, according to the process method requirements, a steel structure construction platform 3 is set up at the tunnel entrance before excavation. The top surface of the construction platform 3 is flush with the temporary inverted arch 11.

[0039] Step 2: After the construction platform 3 is completed, excavation equipment is used to excavate the first pilot tunnel on the construction platform 3. In this embodiment, the first pilot tunnel is the upper left pilot tunnel 21. Excavated soil is loaded into the first hopper 61 through the discharge port 4 at the edge of the construction platform 3. The first hopper 61 is placed on the floor of the shaft 5 and is lifted and transferred by hoisting equipment to the soil pit within the steel structure greenhouse.

[0040] Step 3: As the excavation depth of the upper left guide tunnel 21 advances, the distance that the excavation equipment has to transport the debris to the unloading port 4 of the construction platform 3 increases, and the working efficiency decreases. To address this problem, after the upper left guide tunnel 21 is excavated to the first depth, the first dump truck 71 is introduced to transport the debris on the excavation surface to the unloading port 4 and dump it into the first hopper 61. The first depth is 4 to 8 meters away from the tunnel entrance. Preferably, the first depth is 6 meters away from the tunnel entrance. In view of the narrow space inside the guide tunnel and the inability to turn around, the first dump truck 71 should turn around at the construction platform 3 at the entrance and then reverse into the excavation working face.

[0041] Step 4: When the upper left guide tunnel 21 is excavated to 6 meters, the excavation operation of the second guide tunnel is started. The second guide tunnel is on the same side as the first guide tunnel, that is, the lower left guide tunnel 22. For the transportation of slag from the lower guide tunnel, a second dump truck 72 is used to load the second hopper 62 to transport the slag to the bottom plate of the shaft 5. It should be understood that the second dump truck 72 should transport the slag to outside the projection range of the construction platform 3 so that the hoisting equipment can lift the second hopper 62 for transfer to the slag pool. In other embodiments, as an alternative to this embodiment, the slag discharge method of the upper guide tunnel can also be referred to, and the second hopper 62 is placed on the bottom plate of the shaft 5. The second dump truck 72 transfers the slag out of the tunnel and dumps it into the second hopper 62.

[0042] Step 5: After excavating the upper left pilot tunnel 21 to the second depth, excavation of the third pilot tunnel begins. This third pilot tunnel is the upper right pilot tunnel 23. The second depth is 10 to 20 meters from the tunnel entrance. Preferably, the second depth is 15 meters from the tunnel entrance. The slag removal method for the upper right pilot tunnel 23 is the same as that for the upper left pilot tunnel 21 described in Steps 2 and 3.

[0043] Step 6: Referring to step 4, a fourth pilot tunnel is excavated and soil is transferred. It can be understood that the fourth pilot tunnel is the lower right pilot tunnel 24.

[0044] Step 7: In the CRD method, the excavation of each pilot tunnel is carried out continuously and synchronously. As the upper left pilot tunnel 21 continues to advance to the third depth of 40 to 60 meters from the tunnel entrance (the excavation depth of the upper right pilot tunnel 23 is 25 to 45 meters at this time), if the excavation equipment needs to transfer between the left and right pilot tunnels, the detour path length will reach hundreds of meters, which will significantly increase the transfer time and reduce the operation efficiency. To optimize this link, Figure 2 As shown, a transverse passage 8 is opened on the middle partition wall 12 in the section about 40 to 50 meters away from the tunnel entrance. With the help of this transverse passage 8, the excavation equipment can directly switch the working position between the left and right guide tunnels, thereby drastically shortening the transition distance and greatly improving construction efficiency.

[0045] Step 8: Repeat the above steps as the tunnel excavation depth increases to complete the slag removal construction of the entire tunnel.

[0046] The important components or structural structures in the above construction steps are now further explained.

[0047] The construction platform 3 is assembled with Q235B steel, including beams, support columns, lateral supports, diagonal braces 83 and other components. Its assembled design is convenient for transportation and quick construction in confined spaces. Preferably, the width of the construction platform 3 is not less than 5.0 meters to facilitate mechanical U-turns, and the length extends to the side walls of the shaft 5 on both sides at the tunnel entrance. Specifically, its overall dimensions are 14.0 meters long, 6.0 meters wide and 4.2 meters high. The support columns at the bottom of the construction platform 3 are evenly arranged at intervals of 4.0 meters to ensure the passage of lower pilot tunnel construction machinery and equipment. Preferably, the support columns in the middle of the construction platform 3 are located on the extension line of the tunnel middle wall 12.

[0048] The transverse passage 8 is the core facility for solving the problem of left and right guide tunnel equipment deployment. It is set at approximately 40 to 50 meters along the direction of the tunnel wall 12. Figure 4 As shown, the transverse passage 8 at least includes a crossbeam 81 at the top and columns 82 on both sides of the passage. Preferably, the crossbeam 81 and the columns 82 are made of I20a double-jointed I-beams. During construction, the crossbeam 81 is first firmly welded to the I20a I-beam of the middle partition 12, and then a I20a I-beam column 82 is erected on each side of the passage opening. The top of the column 82 is welded to the crossbeam 81, and the bottom is supported on the temporary inverted arch 11. In order to enhance stability, diagonal braces 83 are set up on both sides of the top of the opening using I20a I-beams. The two ends of the diagonal braces 83 are firmly welded to the columns 82 and the crossbeam 81, respectively, to form a stable triangular support system. By reducing the span of the crossbeam 81, its bearing capacity is effectively enhanced, ensuring that the portal structure meets the initial support stability requirements of the tunnel.

[0049] The excavation equipment is a CLG9035EZTS (G4) hydraulic excavator, a mini excavator. The machine is 2.5 meters tall, and its compact size accommodates the working space of the upper pilot tunnel (4.6 meters high) and the lower pilot tunnel (4.2 meters high).

[0050] The transportation equipment is configured differently according to the location of the pilot tunnel. Figure 3 As shown, the transportation equipment for the upper left guide tunnel 21 and the upper right guide tunnel 23 uses a self-unloading first dump truck 71 and a first hopper 61 (the first hopper 61 is 2.0 meters long, 2.0 meters wide, and 4.0 meters high). The transportation equipment for the lower left guide tunnel 22 and the lower right guide tunnel 24 uses a second dump truck 72 directly loaded with a second hopper 62 (the second hopper 62 is 2.0 meters long, 2.0 meters wide, and 2.0 meters high). The second hopper 62 is loaded on the carriage of the second dump truck 72. After loading, the total height is approximately 2.8 meters. The upper portion of the second hopper 62 is about 1.4 meters above the ceiling of the lower guide tunnel, that is, the bottom surface of the temporary invert 11, leaving a clearance of about 1.4 meters to meet the requirements of small excavator loading operations.

[0051] The hoisting equipment used is a 25-ton bridge crane, housed in a fully enclosed steel structure that covers the shaft 5 and the slag pit. This design effectively suppresses dust and noise generated during slag storage and hoisting, prevents soil contamination from rainwater erosion, and ensures a stable construction environment.

[0052] In summary, the slag discharge method provided by the patent of the present invention is particularly suitable for the construction of a dark tunnel using the CRD method for excavation of four pilot tunnels. The method significantly reduces the ineffective transportation distance and waiting time of mechanical equipment through the systematic optimization of the slag discharge process of the upper and lower pilot tunnels and the rational application of key facilities such as the construction platform 3 and the cross passage 8, thereby greatly improving the construction efficiency. Under the extremely limited constraints of underground space, this method achieves efficient utilization of site resources through scientific planning of process connections and orderly management of space, effectively avoiding the cross-interference and safety accident risks that may be caused by the simultaneous construction of the upper and lower pilot tunnels, and providing reliable technical guarantees for the safe and rapid construction of dark tunnels under complex geological conditions.

[0053] The above description is only a preferred embodiment of the present invention and does not limit the patent scope of the present invention. Any technical equivalent transformation made using the contents of the present invention specification shall fall within the protection scope of the present invention.

Claims

1. A method for removing slag from a shallow, dark-bored tunnel using the CRD method, wherein the tunnel excavation face comprises four pilot tunnels separated by vertical partition walls and horizontal temporary inverts, and wherein: The following steps are involved: Step 1: Setting up a construction platform at the tunnel entrance; the construction platform is flush with the temporary invert arch; Step 2: excavating a first pilot tunnel to a first depth, wherein the first pilot tunnel is an upper pilot tunnel on either side; the excavated soil is transported out through a discharge port provided on the construction platform; Step 3: After the first pilot tunnel is excavated to the first depth, in the subsequent excavation operation, a first dump truck is used to reverse into the first pilot tunnel and transfer the debris to the discharge port on the construction platform for transportation; Step 4: Excavate a second pilot tunnel, which is a lower pilot tunnel on the same side as the first pilot tunnel; use a second dump truck to transfer the debris in the second pilot tunnel to outside the projection range of the construction platform; Step 5: After the first pilot tunnel is excavated to the second depth, a third pilot tunnel is excavated; the third pilot tunnel is an upper pilot tunnel adjacent to the first pilot tunnel; the debris generated in the third pilot tunnel is removed in the same manner as in Steps 2 and 3; Step 6: Excavate a fourth pilot tunnel, which is a lower pilot tunnel on the same side as the third pilot tunnel; remove the debris generated in the fourth pilot tunnel in the same manner as in Step 4; Step 7: When the first pilot tunnel is excavated to the third depth, transverse passages are opened on the intermediate partition walls above and below the temporary invert to allow excavation equipment to pass through; Step 8: As the excavation depth increases, the cross passages are added at intervals; In steps 1 to 8, the debris transported out of the above-mentioned guide tunnels is finally lifted by lifting equipment and transferred to the debris pool.

2. The method for removing slag from a shallow buried tunnel suitable for the CRD method according to claim 1, characterized in that: The outer periphery of the opening of the transverse passage opened on the middle partition wall is provided with a crossbeam and a column; the crossbeam is arranged at the top of the transverse passage; the columns are arranged on both sides of the transverse passage, the tops are welded to the crossbeams, and the bottoms are supported on the temporary inverted arch.

3. The method for removing slag from a shallow buried tunnel suitable for the CRD method according to claim 2, characterized in that: The transverse channel is provided with diagonal braces on both sides of the top; the two ends of the diagonal braces are respectively welded to the crossbeam and the column.

4. The method for removing slag from a shallow buried tunnel suitable for the CRD method according to claim 2, characterized in that: The cross beam and / or the column are made of steel components.

5. The method for removing slag from a shallow buried tunnel suitable for the CRD method according to claim 1, characterized in that: The transverse passages are arranged at intervals of 40 to 50 meters.

6. The method for removing slag from a shallow buried tunnel suitable for the CRD method according to claim 1, characterized in that: A first hopper is provided below the discharge port on the construction platform; the debris produced in the first pilot tunnel and the third pilot tunnel is transported out of the tunnel by the first dump truck and poured into the first hopper through the discharge port.

7. The method for removing slag from a shallow buried tunnel suitable for the CRD method according to claim 1, characterized in that: The second dump truck is provided with a second hopper; the debris generated by the second pilot tunnel and the fourth pilot tunnel is directly loaded into the second hopper and transported by the second dump truck to outside the projection range of the construction platform.

8. The method for removing slag from a shallow buried tunnel suitable for the CRD method according to claim 1, characterized in that: The width of the construction platform is not less than 5 meters, and the length extends to the side walls on both sides of the shaft at the tunnel entrance.

9. The method for removing slag from a shallow buried tunnel suitable for the CRD method according to claim 1, characterized in that: The hoisting equipment adopts a bridge crane.

10. The method for removing slag from a shallow buried tunnel suitable for the CRD method according to claim 1, characterized in that: The first depth is 4 to 8 meters from the tunnel entrance; the second depth is 10 to 20 meters from the tunnel entrance; and the third depth is 40 to 60 meters from the tunnel entrance.

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