Diversion tunnel outlet section slope collapse treatment construction method

Abstract

The invention provides a diversion tunnel outlet section slope collapse treatment construction method. The diversion tunnel outlet section slope collapse treatment construction method comprises the following steps that firstly, a reinforced concrete cover plate is constructed; the construction method comprises the following steps of (1) construction of a cover plate and a concrete lining, (2) consolidation grouting of a diversion tunnel side wall body, (3) collapse section locking and collapse body deslagging construction, and (4) treatment of a cavity between the cover plate and the concrete lining, and therefore the construction of collapse treatment of the diversion tunnel outlet section side slope is completed, and the method has the advantages that the construction period is shortened, local materials are used, economy and environmental protection are achieved, safety is high, and the diversion tunnel can be rapidly and normally tunneled.

Description

Technical Field

[0001] The invention relates to the technical field of slope collapse treatment, in particular to a construction method for slope collapse treatment at an outlet section of a diversion tunnel. Background Art

[0002] The existing technology for handling the collapse of the slope at the exit section of the diversion tunnel is to clean up the collapsed slag on the slope inside the tunnel, change the tunnel body of the collapsed section from dark excavation to open tunnel construction, clean up the empty shell of the collapsed slope, lock the slope, excavate the slope, strengthen the slope support, lock the tunnel mouth, and excavate the open arch into the tunnel normally.

[0003] The above construction method takes too long to deal with the landslide and is unsafe. The state of the slope after the landslide is in a fluid state. The process of clearing the landslide is very likely to cause a secondary landslide, and it affects the normal construction of the diversion tunnel, resulting in a significant extension of the construction period of the entire project.

[0004] In addition, considering the problem of transporting and discarding landslide debris, the difficulty of handling in the existing technology is further increased.

[0005] In order to solve a series of problems existing in the existing landslide treatment methods, such as long construction period, high cost, poor safety, and high treatment cost caused by affecting the normal construction of diversion tunnels, it is necessary to improve the landslide treatment methods. Summary of the invention

[0006] The purpose of the present invention is to address the deficiencies of the prior art and thus provide a construction method for treating the side slope collapse at the exit section of a diversion tunnel, which shortens the construction period, uses local materials, is economical and environmentally friendly, has high safety, and can allow the diversion tunnel to be excavated quickly and normally.

[0007] In order to achieve the above object, the technical solution adopted by the present invention is: a construction method for handling the slope collapse at the outlet section of a diversion tunnel, comprising the following steps: Step 1) Construction of reinforced concrete cover plate: Step 1.1) Lay an I-beam scaffold at the collapsed hole on the top arch of the diversion tunnel. The outer end of the I-beam is placed on the open arch of the exit, and the inner end is inserted into the temporary stable slope formed after the collapse, forming a simply supported beam load-bearing structure; Step 1.2) Use steel pipes to increase the density of the I-beams in the horizontal direction to increase the overall force; Step 1.3) Lay steel mesh on top of the scaffolding made of I-beams and steel pipes; Step 1.4) Set up a full-height scaffolding support under the scaffolding made of I-beams and steel pipes, close the scaffolding with bridle boards and lay an isolation layer, and use fluidized concrete to pour to form a reinforced concrete cover; Step 2) Consolidation grouting of diversion tunnel side wall: Step 2.1) Before pouring the concrete in step 1.4), insert the grouting pipe into the side wall of the reinforced concrete cover to a set depth. After the reinforced concrete cover is poured, use concrete weight to perform surface sealing grouting; Step 2.2) Build a dry stone retaining wall outside the bottom side wall of the reinforced concrete cover plate, bury the grouting flower pipe after the plain sprayed concrete is sealed, and carry out the closed grouting of the lower side wall to complete the consolidation grouting of the diversion tunnel side wall; Step 2.3) For retaining walls, backfill with slag to stabilize the base; Step 3) Locking of the landslide section and slag removal of the landslide body: Step 3.1) Install two full-section vertical steel supports at the exposed arch end, set support beams between the vertical steel supports, make horizontal supports along the designed excavation line at the bottom of the tunnel, drive locking anchor rods into the side walls, and weld them firmly to the steel supports to form a lock; Step 3.2) When cleaning the slag in the spandrel, first install self-propelled anchors, randomly distributed, and continuously deepened as the excavation progresses. Anchor construction and slag cleaning are carried out simultaneously to ensure that the effective length of the anchor meets the quality requirements. When excavating to the designed excavation line, the exposed surface is sealed with plain concrete spraying; then consolidation grouting treatment is carried out; Step 3.3) Carry out slag removal in stages. First, clean the part above the spandrel. Then, install the top steel support based on the vertical steel support and weld and fix it with the inserted steel bars extending downward from the original reinforced concrete cover plate. Step 3.4) After the top arch concrete pouring is completed, the side wall treatment is carried out. The cleaning and support of the left and right side walls are carried out separately, and the same side is treated in sections and layers; Step 4) Treatment of the cavity between the cover plate and the concrete lining: The cavity between the cover plate and the concrete lining is backfilled with grouting or directly backfilled with concrete; At this point, the construction of slope collapse treatment at the exit section of the diversion tunnel has been completed.

[0008] Preferably, in step 1.1), the I-beams are distributed in a fan-shaped pattern in the horizontal direction, with a spacing of ≥1m.

[0009] Preferably, in step 1.1), one end of the I-beam inserted into the slope is sharpened and driven into the stable slope 2-3m.

[0010] Preferably, in step 1.2), the diameter of the reinforcement steel pipe is ≥φ48mm.

[0011] Preferably, in step 1.3), the main reinforcement of the steel mesh is ≥25 mm steel, and the main reinforcement is parallel to the hole axis; the distribution reinforcement is ≥16 mm steel, and the spacing is at least 15 cmÍ15 cm.

[0012] Preferably, in step 1.4), the isolation layer is made of colored striped cloth.

[0013] Preferably, in step 1.4), C20 fluid concrete is used for pouring concrete, the pouring thickness is at least 1m, and a 5cm protective layer is left on the upper part of the slab.

[0014] Preferably, in step 2.1), the pressure of the closed grouting is controlled by three-level pressure control, and the three-level pressures are 0.1Mpa, 0.2Mpa, and 0.3Mpa respectively, and the grouting volume of a single hole is controlled to be 600L / hole.

[0015] Preferably, in step 2.2), the side wall consolidation grouting pipe is buried in a plum blossom pattern with a spacing of 1m×1m, with an insertion angle of 10° and a hole depth of 5 to 6m into the landslide body. The grouting water-cement ratio is 0.6:1 cement slurry, mixed with 3% water glass; when the unit grouting volume exceeds 30L / min, intermittent grouting is used, or the injection volume is limited, and the injection volume of a single hole does not exceed 1000L.

[0016] Preferably, it also includes construction treatment of the affected section. For those affected by the collapse of different pile numbers at the outlet section of the diversion tunnel, consolidation treatment is carried out. First, concrete is sprayed on the unstable cracks, and then grouting treatment is carried out.

[0017] Compared with the prior art, the present invention has outstanding substantive features and significant progress. Specifically, the present invention uses a steel-concrete protective cover to treat the landslide, and then uses local materials on site, and uses the landslide slag to backfill the slope for the second time to restore the slope status quo. The processing speed is fast, and it is environmentally friendly and reduces the processing cost. Through monitoring and measuring project observations, various displacements are within the allowable range of the design, meeting the needs of slope stability at the entrance section and safe excavation in the tunnel, and achieving the expected effect. The method uses local materials, is economical, convenient, safe, and fast, and provides reference experience for landslides at the entrance section. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a vertical view of a construction method for handling slope collapse at the outlet section of a diversion tunnel in the present invention.

[0019] Figure 2 The present invention is a plan view of the laying of I-beams in a construction method for handling the collapse of a slope at an outlet section of a diversion tunnel.

[0020] Figure 3 It is a cross-sectional view of a construction method for handling side slope collapse at the outlet section of a diversion tunnel in the present invention. DETAILED DESCRIPTION

[0021] The technical solution of the present invention is further described in detail below through specific implementation methods.

[0022] like Figure 1-Figure 3 As shown, a construction method for handling the side slope collapse at the outlet section of a diversion tunnel comprises the following steps: Step 1) Construction of reinforced concrete cover 1.1 An I-beam scaffold is laid in the collapsed hole on the top arch of the diversion tunnel. One end of the I-beam is placed on the exposed arch at the exit, and the other end is inserted into the temporary stable slope formed after the collapse, forming a simply supported beam load-bearing structure; the I-beams are distributed horizontally in a fan-shaped pattern, with a spacing of 1.0m (which can be adjusted according to the on-site conditions); the end of the I-beam inserted into the slope is sharpened and driven into the slope 2 to 3m; 1.2 To ensure the overall force of the I-beam, φ48 steel pipes (50cm spacing) are used for cross-sectional reinforcement, see attached Figure 1 .

[0023] 1.3 In order to prevent the cover slab concrete from being affected by the loose body load that may appear on the top and causing the cover slab to crack, a single layer of steel mesh is arranged on the top of the I-beam. The main reinforcement is Φ25 (parallel to the axis of the hole), the distribution reinforcement is Φ16 (perpendicular to the axis of the hole), and the spacing is 15cm×15cm.

[0024] 1.4 A full-height scaffolding support is set up at the bottom of the I-beam and enclosed with a walkway board. In order to avoid leakage when pouring concrete, a layer of colored strips is laid on the upper part of the walkway board. For safety reasons, C20 flowing concrete is poured with a thickness of 1.0m, and a 5cm protective layer is left on the upper part of the walkway board.

[0025] After the reinforced concrete cover is formed, flexible materials such as logs and bamboo are laid on the top with a thickness of about 1.0m to prevent the slope from collapsing again and damaging the concrete cover.

[0026] Step 2) Consolidation grouting of the left wall of the diversion tunnel 2.1 The grouting of the diversion hole is carried out in two steps. First, the grouting flower pipe is inserted into the side wall of the concrete cover 2.0m before the concrete pouring. After the concrete pouring is completed, the surface is sealed with grouting using concrete weight. The grouting pressure adopts three levels of 0.1Mpa, 0.2Mpa, and 0.3Mpa, and the single hole grouting volume is controlled at 600L / hole to avoid slurry loss.

[0027] 2.2 In order to ensure the stability of the slope foot after the slope collapses again, a retaining wall with a height of 2.0m and a width of 0.8m is built 5m away from the excavated slope foot line, 0.5m deep into the foundation, and sealed with 10cm plain sprayed concrete, and then a grouting pipe is buried to grout the lower side wall.

[0028] The side wall consolidation grouting pipes are buried in a plum blossom pattern with a spacing of 1m×1m, with an insertion angle of 10° and a hole depth of 5 to 6m into the landslide body. The grouting water-cement ratio is 0.6:1 cement slurry with 3% water glass added.

[0029] In order to prevent the loss of slurry due to surface slurry bubbling during the grouting process, intermittent grouting should be adopted when the unit grouting volume exceeds 30L / min, or the injection volume should be limited, and the injection volume of a single hole shall not exceed 1000L.

[0030] 2.3) For retaining walls, backfill with slag to stabilize the base; Step 3) Locking of the landslide section and slag removal of the landslide body 3.1 Before slag discharge, install two full-section steel supports at the exposed arch end with a spacing of 1.0m. Use Φ25mm steel pipes to connect the steel supports. Provide lateral support along the designed excavation line at the bottom of the tunnel. Drive locking anchor rods on the side walls with a length of 3.0m and a spacing of 1.0m. They are firmly welded to the steel supports to form a lock.

[0031] 3.2 To ensure the stability of the left wall during the removal of slag, when removing slag from the arch shoulder, first insert a Φ25mm self-propelled anchor rod with a length of 3m and random arrangement. The anchor rod construction and slag removal are carried out simultaneously, and the depth is continuously increased as the excavation progresses to ensure that the effective length of the anchor rod meets the quality requirements. When the excavation reaches the designed excavation line, the exposed surface is sealed with 10cm of concrete sprayed; then consolidation grouting is carried out.

[0032] 3.3 Carry out slag removal construction in steps. First clean the part above the arch shoulder, install the top steel support with a spacing of 1.0m, and weld the dowel bars extending from the original cover slab concrete pouring.

[0033] 3.4 After the top arch concrete is poured, the side wall treatment shall be carried out. The cleaning and support of the left and right side walls shall be carried out separately. The same side shall be divided into sections (in the axial direction, in principle, the section length is half of the side wall of the collapsed section) and layers (it is planned to be excavated in two times, in principle, the height of each layer is half of the height of the side wall).

[0034] Step 4) Treatment of the cavity between the cover plate and the concrete lining The cavity between the cover plate and the concrete lining is backfilled with grouting or directly backfilled with concrete. In order to speed up the treatment of the landslide section, it should be considered to reserve a number of φ50cm holes on the upper part of the cover plate when pouring the cover plate concrete, which can be used as the feed inlet for cavity backfill and poured together with the top arch concrete lining.

[0035] After the concrete lining of the top arch of the collapsed section is completed, when the strength meets the requirements, the upper collapsed hole is filled with slag, and the surface is re-meshed and sprayed with concrete for protection.

[0036] Step 5) How to deal with the affected segments Due to the collapse of the exit section of the diversion tunnel (pile number 0+150~0+137), the mesh sprayed concrete of the exit pile number 0+140~0+128 was torn, with the widest crack reaching 3cm. The local surface was loose, and this part should be consolidated. First, 10cm thick concrete was sprayed on the cracked part, and then grouting was performed. Grouting range: pile number 0+140~0+128, the grouting pipe uses a self-propelled anchor rod with a length of 4m, perpendicular to the rock surface; hole layout: 2m spacing, plum blossom arrangement; grouting parameters: cement slurry, slurry concentration is divided into five levels, and the water-cement ratio is 3:1, 2:1, 1:1, 0.8:1, 0.5:1; grouting pressure: 0.2Mpa.

[0037] Finally, it should be noted that: The above describes in detail the preferred implementation of this patent, but this patent is not limited to the above implementation. Various changes can be made within the knowledge scope of ordinary technicians in this field without departing from the purpose of this patent.

Claims

1. A construction method for handling slope collapse at the outlet section of a diversion tunnel, characterized in that: The following steps are involved: Step 1) Construction of reinforced concrete cover plate: Step 1.1) Lay an I-beam scaffold at the collapsed hole on the top arch of the diversion tunnel. The outer end of the I-beam is placed on the open arch of the exit, and the inner end is inserted into the temporary stable slope formed after the collapse, forming a simply supported beam load-bearing structure; Step 1.2) Use steel pipes to increase the density of the I-beams in the horizontal direction to increase the overall force; Step 1.3) Lay steel mesh on top of the scaffolding made of I-beams and steel pipes; Step 1.4) Set up a full-height scaffolding support under the scaffolding made of I-beams and steel pipes, close the scaffolding with bridle boards and lay an isolation layer, and use fluidized concrete to pour to form a reinforced concrete cover; Step 2) Consolidation grouting of diversion tunnel side wall: Step 2.1) Before pouring the concrete in step 1.4), insert the grouting pipe into the side wall of the reinforced concrete cover to a set depth. After the reinforced concrete cover is poured, use concrete weight to perform surface sealing grouting; Step 2.2) Build a dry stone retaining wall outside the bottom side wall of the reinforced concrete cover plate, bury the grouting flower pipe after the plain sprayed concrete is sealed, and carry out the closed grouting of the lower side wall to complete the consolidation grouting of the diversion tunnel side wall; Step 2.3) For retaining walls, backfill with slag to stabilize the base; Step 3) Locking of the landslide section and slag removal of the landslide body: Step 3.1) Install two full-section vertical steel supports at the exposed arch end, set support beams between the vertical steel supports, make horizontal supports along the designed excavation line at the bottom of the tunnel, drive locking anchor rods into the side walls, and weld them firmly to the steel supports to form a lock; Step 3.2) When cleaning the slag in the spandrel, first install self-propelled anchors, randomly distributed, and continuously deepened as the excavation progresses. Anchor construction and slag cleaning are carried out simultaneously to ensure that the effective length of the anchor meets the quality requirements. When excavating to the designed excavation line, the exposed surface is sealed with plain concrete spraying; then consolidation grouting treatment is carried out; Step 3.3) Carry out slag removal in stages. First, clean the part above the spandrel. Then, install the top steel support based on the vertical steel support and weld and fix it with the inserted steel bars extending downward from the original reinforced concrete cover plate. Step 3.4) After the top arch concrete pouring is completed, the side wall treatment is carried out. The cleaning and support of the left and right side walls are carried out separately, and the same side is treated in sections and layers; Step 4) Treatment of the cavity between the cover plate and the concrete lining: The cavity between the cover plate and the concrete lining is backfilled with grouting or directly backfilled with concrete; At this point, the construction of slope collapse treatment at the exit section of the diversion tunnel has been completed.

2. The construction method for handling the side slope collapse at the diversion tunnel outlet section according to claim 1 is characterized in that: In step 1.1), the I-beams are distributed in a fan-shaped pattern in the horizontal direction, with a spacing of ≥ 1m.

3. The construction method for handling the slope collapse at the diversion tunnel outlet section according to claim 1 is characterized in that: In step 1.1), one end of the I-beam inserted into the slope is sharpened and driven into the stable slope 2-3m.

4. The construction method for handling the slope collapse at the diversion tunnel outlet section according to claim 1 is characterized in that: In step 1.2), the diameter of the reinforcement steel pipe is ≥φ48mm.

5. The construction method for handling the slope collapse at the diversion tunnel outlet section according to claim 1 is characterized in that: In step 1.3), the main reinforcement of the steel mesh shall be ≥25mm steel bars, and the main reinforcement shall be parallel to the hole axis; the distribution reinforcement shall be ≥16mm steel bars, and the spacing shall be at least 15cmÍ15cm.

6. The construction method for handling the side slope collapse at the diversion tunnel outlet section according to claim 1 is characterized by: In step 1.4), the isolation layer is made of colored striped cloth.

7. The construction method for handling the side slope collapse at the diversion tunnel outlet section according to claim 1 is characterized by: In step 1.4), C20 fluid concrete is used for pouring concrete, and the pouring thickness is at least 1m, and a 5cm protective layer is left on the upper part of the slab.

8. The construction method for handling the slope collapse at the diversion tunnel outlet section according to claim 1 is characterized by: In step 2.1), the closed grouting pressure is controlled by three-level pressure control, and the three-level pressures are 0.1Mpa, 0.2Mpa, and 0.3Mpa respectively, and the single-hole grouting volume is controlled to be 600L / hole.

9. The construction method for handling the side slope collapse at the diversion tunnel outlet section according to claim 1 is characterized by: In step 2.2), the side wall consolidation grouting pipes are buried in a plum blossom pattern with a spacing of 1m×1m, with an insertion angle of 10° and a hole depth of 5 to 6m into the landslide body. The grouting water-cement ratio is 0.6:1 cement slurry with 3% water glass added. When the unit grouting volume exceeds 30L / min, intermittent grouting is adopted, or the injection volume is limited, and the injection volume of a single hole does not exceed 1000L.

10. The construction method for handling the side slope collapse at the diversion tunnel outlet section according to claim 1 is characterized in that: It also includes the construction treatment of the affected section. For those affected by the collapse of different pile numbers at the outlet section of the diversion tunnel, consolidation treatment is carried out. First, concrete is sprayed on the unstable cracks, and then grouting treatment is carried out.

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