Step terrain high-low amplitude diaphragm wall construction method

Abstract

The invention discloses a step terrain high-low amplitude diaphragm wall construction method which is mainly suitable for construction of a deep foundation pit support structure. The construction process comprises step terrain multi-elevation underground diaphragm wall process optimization construction and high-low amplitude underground diaphragm wall connection construction, and the construction process is reasonably divided into three construction stages aiming at the problems that step type site construction operation is difficult and high-low amplitude underground diaphragm wall sudden change section connection construction is difficult: in the first stage, low-elevation site underground diaphragm wall construction is completed at first, and high-low amplitude underground diaphragm wall sudden change section connection construction is completed at the second stage; in the third stage, soil is backfilled on the basis of the first stage to increase the high working face of the high-field flat-section trenching machine, so that transition sections with different elevations are constructed; through cooperation of multiple links such as backfilling at the joint, arranging a plugging template, arranging a crawler crane for hoisting and the like, the slab staggering joint problem is solved. The construction method effectively solves the problem that the underground diaphragm wall is complex in construction due to inconsistent field level elevation, guarantees the smooth progress of the project, and improves the construction quality and efficiency.

Description

Technical Field

[0001] The invention relates to the technical field of deep foundation pit enclosure construction, and in particular to a method for constructing a high-low-amplitude ground-connected wall on a stepped terrain. Background Art

[0002] In the construction of subway stations, underground continuous walls are mostly used as retaining structures for deep foundation pit construction. Stations are often built on municipal roads with flat sites, uniform elevations of ground-connected walls, and good working environments. However, in some station construction scenarios outside the main roads of the city, the station foundation pit is partially close to high-slope embankments or mountains. In order to reduce the bias pressure effect of embankment filling and mountains on foundation pit excavation, the design usually adopts a ground layout with different height differences between the biased part and the rest of the section, forming a high-low span ground-connected wall structure, which cannot provide an effective working surface for troughing and steel cage hoisting construction. This not only greatly increases the construction difficulty coefficient, but also requires repeated deployment of equipment and high-support formwork construction of local ground-connected walls, bringing severe challenges and safety risks to the construction of the retaining structure of the entire subway station.

[0003] At present, the conventional construction practice is to deploy a set of trenching machines and crawler cranes in the high-field flat section to be responsible for the construction of the high-field flat section. For the local ground-connected wall above the ground, two steps are used for construction: 1. The conventional underwater construction process is used to construct the part below the ground first, and then the protruding part above the ground is constructed through high-support formwork and pile connection. 2. For the construction of the ground-connected wall in the sloped part of the site, the method of supplementary backfilling of the high step platform is adopted to provide the site transition width ground-connected wall trenching and mud wall protection working surface. This construction process is complex and has poor safety.

[0004] In summary, there are many problems in the construction of conventional ground-connected walls in stepped terrain and high and low-amplitude ground-connected walls. There is an urgent need for a safe, convenient and scientific construction method for ground-connected walls in stepped terrain and high and low-amplitude ground-connected walls. Summary of the invention

[0005] The purpose of the present invention is to provide a method for constructing high and low-amplitude ground ties on stepped terrain in response to the problems existing in the prior art, so as to solve the problems of unreasonable construction sequence on stepped terrain, complex construction procedures for sudden change connection sections of high and low-amplitude ground ties, and low safety in traditional construction methods, so as to meet the needs of safe construction of underground projects such as track construction and station excavation.

[0006] The present invention is achieved by adopting the following technical solutions: A method for constructing a high-low-width ground tether wall on a stepped terrain, comprising optimizing the construction process of a multi-standard high-width ground tether wall on a stepped terrain and connecting the high-low-width ground tether wall. The construction steps are as follows: Step 1: Divide the construction area into three parts: low-field flat area, high-field flat area and site slope area. Divide the regional ground-connected wall into three stages of construction. The first stage is to construct the ground-connected wall at the low-field flat area, the second stage is to construct the ground-connected wall at the high-field flat area, and the third stage is to connect and construct the ground-connected wall at the high-low amplitude sudden change section. On the basis of the first stage, backfill the soil to increase the high working surface of the trenching machine in the high-field flat section and construct the transition section at different elevations. The optimized construction process of the multi-elevation ground-connected wall on the stepped terrain comprehensively considers the hoisting capacity of the crawler crane and the safety operation requirements of the trenching machine near the edge before construction, and plans the site step slope positions twice. The first slope is to complete the hoisting of all the ground-connected walls on the high step. The second backfill slope is to ensure that the trenching machine has sufficient operating width near the edge to complete the trenching construction, thereby avoiding the crawler crane from climbing back and forth.

[0007] Step 2: Divide the site into slopes according to the construction area to ensure that the slope foot does not affect the construction of the low-field flat ground connecting wall, and then complete the construction of the low-field flat ground connecting wall.

[0008] Step 3: Arrange crawler crane at low-elevation site, calculate whether the lifting height is met according to the length of steel cage, hoisting equipment length, site elevation and crawler crane working range, and hoist the steel cage connected to the wall on the high-elevation flat ground that can be hoisted from the low-elevation site; for some steel cages connected to the wall on the high-elevation flat ground that cannot be hoisted from the low-elevation site, hoist them directly at the high-elevation site.

[0009] Step 4. In order to complete the construction of the ground-connected wall in the section with sudden changes in height, the high-level site is leveled and filled and widened to form a filling platform. The filling platform needs to ensure that the side line of the trenching machine is more than 3m away from the top of the slope during the trenching construction of the ground-connected wall in the section with sudden changes in height; during the filling process of the filling platform, attention should be paid to ensuring the combination of the new and old roadbeds, and at the same time ensuring that the filling compaction degree is not less than 91%, so as to provide safe working conditions for the trenching machine and crawler crane; by backfilling the soil, widening the high-level construction platform, and backfilling the high-step platform, a working surface for the transitional width of the site ground-connected wall trenching and mud wall protection is provided.

[0010] Step 5. Use a slotting machine to slot the ground-connected wall at the high-low amplitude sudden change section, arrange crawler cranes at low elevation sites, select lifting points and hoists according to cage weight and length, and cooperate in an orderly manner when lifting with two machines; the main crane lowers the steel cage, pours concrete, and completes the construction of all ground-connected walls; after the steel cage is lowered into place, promptly backfill the over-grasping area on the back of the anti-circumvention steel plate with sandbags to reduce the amount of concrete bypass during the pouring process. First, construct the ground-connected wall at the low elevation site to ensure the connection of subsequent processes, then carry out related operations on the ground-connected wall at the high elevation site, and finally backfill the soil to form a stable platform to construct the transition section and stabilize the soil. The steel cage structure of the high-low amplitude ground-connected wall connection section is used to set up anti-circumvention steel plates, backfill sandbags on the back of the steel plate at the over-excavation of the slot section, and arrange crawler cranes for lifting and other multi-link coordination, which effectively solves the problem of misaligned connection, and overall ensures smooth construction, stable structure, and improved construction efficiency and quality.

[0011] Further preferred: the anti-circumvention steel plate is welded to the prefabricated ground-connected wall reinforcement cage, and its width is smaller than the width of the excavated ground-connected wall groove section to prevent the concrete from overflowing from the gap and circumventing during the pouring process.

[0012] Further preferably, the anti-bypass iron sheets are welded on both sides of the anti-bypass steel plate to enhance the anti-bypass capability of the concrete.

[0013] The bottom surface position of the anti-circulation steel plate welded and installed is consistent with the top surface height of the low-field flat concrete that has been constructed, ensuring that the gap between the bottom surface of the anti-circulation steel plate and the top of the low-width ground-connected wall is small after the steel cage is hoisted and lowered, and the concrete cannot overflow and circumvent. The steel cage structure of the high-low ground-connected wall connection section is the last closed width of construction. When forming the groove, the blade part of the groove forming machine grab has a certain width and shape. In order to ensure the grabbing effect, the blade may exceed the designed wall width during the opening and closing process; when the high-low connection ground-connected wall steel cage is made, effective measures are taken for the high-width ground-connected wall steel cage to prevent concrete circumference: Under the premise of ensuring the thickness of the protective layer on the side of the low-width ground-connected wall, a section of U-shaped anti-circulation steel plate is welded to the steel cage as a blocking template during the concrete pouring process. It is necessary to ensure that the bottom surface of the anti-circulation steel plate is consistent with the top elevation of the low-width ground-connected wall after the steel cage is hoisted and lowered.

[0014] The beneficial effects of the present invention are: 1. During construction, the construction method and process are accurately implemented. First, the construction of the ground-connected wall at the low elevation site is properly completed to reserve a high-quality working surface for the subsequent procedures; then the ground-connected wall at the high elevation site is completed according to the capacity of the crawler crane; finally, the soil is backfilled to form a stable platform to construct the ground-connected wall at the elevation connection section. In view of the problem of the construction of the ground-connected wall at the high and low sections, a steel cage structure for the connection section of the high and low amplitude ground-connected wall is proposed to reduce the concrete bypass during the construction process and the subsequent excavation of the excess concrete of the ground-connected wall. All links in the process cooperate closely to effectively solve the construction problems of the high and low amplitude ground-connected wall, ensure the quality and progress of the project, and show the broad application prospects of this construction method in the construction of ground-connected walls in complex terrains in similar rail transit projects.

[0015] 2. It effectively solved the complex problem of ground-anchored wall construction caused by inconsistent site elevation, ensured the smooth progress of the project, improved construction quality and efficiency, and improved the construction quality of the sudden connection sections of high and low-amplitude ground-anchored walls. At the same time, it has important reference and reference significance for the construction of ground-anchored walls under similar complex site conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a plan view of step terrain and high and low amplitude ground-connected wall working conditions; Figure 2 It is a schematic diagram of the longitudinal section of the step terrain and high and low amplitude ground-connected wall working conditions; Figure 3It is a detailed zoning map of step terrain and high and low-width ground-connected walls; Figure 4 It is the detailed longitudinal section zoning diagram of step terrain, high and low-width ground-connected walls; Figure 5 This is a schematic diagram of the construction of low-field flat ground connecting wall; Figure 6 This is a schematic diagram of the construction of the high-ground flat ground connecting wall; Figure 7 Schematic diagram of widening the platform for high-ground level filling; Figure 8 It is a steel cage structure for the connection section of high and low-amplitude ground-connected walls; Fig. 9 for Figure 8 A top view schematic diagram of Fig.10 This is a construction diagram of the lowering of the steel cage structure of the high-low ground-connected wall connection section; Fig.11 for Fig.10 A top view schematic diagram of Fig.12 This is a schematic diagram of the construction of the ground-connected wall connection in the high-low sudden change section; The names of the parts corresponding to the serial numbers in the figure are: 1. Low-field flat ground connecting wall, 2. High-field flat ground connecting wall, 3. Site slope, 4. Ground connecting wall with sudden high and low amplitude changes, 5. Crawler crane, 6. Filling platform, 7. Steel cage, 8. Anti-circulation steel plate, 9. Filling sandbags, 10. High-level site leveling, 11. Low-level site leveling, 12. Embankment slope line, 13. High-level site flat ground, 14. Low-level site flat ground, 15. Boundary line of high and low amplitude ground connecting walls, 16. Slope top line, 17. Slope toe line, 18. Original slope, 19. Backfill slope, 20. High-level site leveling section of the completed trough, 21. Low-level site leveling section of the completed trough, 22. Trough forming machine. DETAILED DESCRIPTION

[0017] The technical solutions in the invention are clearly and completely described below in conjunction with the embodiments. The described embodiments are only a part of the present invention, rather than all the embodiments. Example

[0018] A method for constructing a high-low-width tethered wall on a stepped terrain, comprising optimizing the construction process of a multi-standard high-width tethered wall on a stepped terrain and connecting the high-low-width tethered wall. The construction steps are as follows: Step 1: Figure 1-Figure 4As shown, the construction area is divided into three parts: low-field flat area 11, high-field flat area 10 and site slope area 3. The regional ground-connected wall is divided into three stages of construction. The first stage is to construct the ground-connected wall 1 at the low-field flat area, the second stage is to construct the high-field flat ground-connected wall 2, and the third stage is to connect and construct the ground-connected wall 4 at the high-low amplitude sudden change section. On the basis of the first stage, backfill the soil to increase the high-field flat section trenching machine's high working surface to construct the transition section with different elevations. The optimized construction process of the multi-elevation ground-connected wall on the stepped terrain comprehensively considers the hoisting capacity of the crawler crane and the safety operation requirements of the trenching machine's edge before construction, and plans the site step slope positions twice. The first slope is to complete the hoisting of all the ground-connected walls on the high step. The second backfill slope is to ensure that the trenching machine has sufficient edge working width in the site slope connection section to complete the trenching construction, thereby avoiding the crawler crane from climbing back and forth.

[0019] Step 2: Figure 5 , according to the construction area, the site slope 3 is graded to ensure that the slope foot does not affect the construction of the low-field flat ground connecting wall 1, and then the low-field flat ground connecting wall 1 is completed.

[0020] Step 3: Figure 6 Arrange a crawler crane 5 at a low-elevation site, calculate whether the lifting height is met based on the length of the steel cage, the length of the hoisting device, the site elevation and the working range of the crawler crane, and hoist the steel cage 7 of the high-site flat ground connecting wall 2 that can be hoisted from the low-elevation site; for the steel cage 7 of the high-site flat ground connecting wall 2 that cannot be hoisted from the low-elevation site, hoist it directly at the high-elevation site.

[0021] Step 4: Figure 7 In order to complete the construction of the ground-connecting wall 4 at the sudden change of height, the high-level site 10 is filled and widened to form a filling platform 6. The filling platform 6 needs to ensure that the side line of the trenching machine 22 is more than 3m away from the top of the slope during the trenching construction of the ground-connecting wall 4 at the sudden change of height; during the filling process of the filling platform 6, attention should be paid to ensuring the combination of the new and old roadbeds, and at the same time ensuring that the filling compaction degree is not less than 91%, so as to provide safe working conditions for the trenching machine 22 and the crawler crane 5; by backfilling the soil, widening the high-level construction platform, and backfilling the high-step platform, a working surface for the transitional width of the site ground-connecting wall trenching and mud wall protection is provided.

[0022] Step 5: Figure 10-12, use the trenching machine 22 to trench the ground-connected wall 4 at the sudden change of height, arrange the crawler crane 5 at the low elevation site, select the lifting point and hoisting equipment according to the weight and length of the cage, and cooperate in an orderly manner when lifting with two machines; the main crane lowers the steel cage 7, pours concrete, and completes the construction of all ground-connected walls; after the steel cage 7 is lowered into place, the over-grasping area on the back of the anti-circulation steel plate 8 is backfilled with sandbags 9 in time to reduce the amount of concrete bypass during the pouring process. First, construct the ground-connected wall at the low elevation site to ensure the connection of subsequent processes, and then carry out related operations of the ground-connected wall at the high elevation site, and finally backfill the soil to form a stable platform to construct the transition section and stabilize the soil. The steel cage structure of the high-low amplitude ground-connected wall connection section is used to set the anti-circulation steel plate, backfill the sandbags on the back of the steel plate at the over-excavation of the trench section, and arrange the crawler crane for lifting, etc., which effectively solves the problem of misaligned connection, and overall ensures smooth construction, stable structure, and improved construction efficiency and quality.

[0023] The anti-circumvention steel plate 8 is welded to the prefabricated ground-connected wall reinforcement cage, and its width is smaller than the width of the excavated ground-connected wall groove section to prevent the concrete from overflowing from the gap and circumventing during the pouring process.

[0024] The anti-bypass iron sheets are welded on both sides of the anti-bypass steel plate 8 to enhance the anti-bypass capability of the concrete.

[0025] The bottom surface position of the anti-circumference steel plate 8 welded and installed is consistent with the top surface height of the low-field flat concrete that has been constructed, ensuring that after the steel cage is hoisted and lowered, the gap between the bottom surface of the anti-circumference steel plate and the top of the low-width ground-connected wall is small, and concrete cannot overflow and circumferentially flow.

[0026] The steel cage structure of the high-low ground-connected wall connection section is the last closed width of the construction. When the trench is formed, the blade of the trenching machine grab has a certain width and shape. In order to ensure the grabbing effect, the blade may exceed the designed wall width during the opening and closing process; Figure 8 When making the steel cage of the high-low connecting ground-connected wall, effective measures should be taken to prevent concrete bypass for the steel cage of the high-width ground-connected wall: on the premise of ensuring the thickness of the protective layer on the side of the low-width ground-connected wall, a section of U-shaped anti-bypass steel plate is welded to the steel cage as a blocking template during the concrete pouring process. It is necessary to ensure that the bottom surface of the anti-bypass steel plate is consistent with the top elevation of the low-width ground-connected wall after the steel cage is hoisted and lowered.

[0027] The above description is not a limitation of the present invention, and the present invention is not limited to the above examples. Any changes, modifications, additions or substitutions made by ordinary technicians in this technical field within the essential scope of the present invention should fall within the protection scope of the present invention.

Claims

1. A method for constructing a high-low-amplitude ground-connected wall on a stepped terrain, characterized in that: It includes the optimized construction of multi-level high-rise tethered walls on stepped terrain and the connection construction of high and low-level tethered walls. The construction steps are as follows: Step 1: Divide the construction area into three parts: low-field flat area (11), high-field flat area (10) and site slope area (3). Divide the regional ground-connected wall into three stages of construction: the first stage is to construct the ground-connected wall at the low-field flat area (1), the second stage is to construct the ground-connected wall at the high-field flat area (2), and the third stage is to connect and construct the ground-connected wall at the high-low amplitude sudden change area (4); Step 2: Slope the site side slope (3) according to the construction area, ensure that the slope foot does not affect the construction of the low-field flat ground connecting wall (1), and then complete the construction of the low-field flat ground connecting wall (1); Step 3: Arrange a crawler crane (5) at a low-elevation site, calculate whether the lifting height is met based on the length of the steel cage, the length of the hoisting device, the site elevation and the working range of the crawler crane, and hoist the steel cage (7) of the high-site flat ground connecting wall (2) that can be hoisted from the low-elevation site; hoist the steel cage (7) of the high-site flat ground connecting wall (2) that cannot be hoisted from the low-elevation site directly at the high-elevation site; Step 4: In order to complete the construction of the ground-connecting wall (4) at the sudden change in height, the high-standard site (10) is filled and widened to form a filling platform (6). The filling platform (6) needs to ensure that the side line of the trenching machine (22) is more than 3m away from the top of the slope during the trenching construction of the ground-connecting wall (4) at the sudden change in height. During the filling process of the filling platform (6), attention should be paid to ensuring the combination of the new and old roadbeds, and at the same time ensuring that the filling compaction degree is not less than 91%, so as to provide safe working conditions for the trenching machine (22) and the crawler crane (5); Step 5: Use a slotting machine (22) to slot the ground-connected wall (4) at the height change section. Arrange a crawler crane (5) at a low elevation site, select the lifting point and lifting equipment according to the weight and length of the cage, and cooperate in an orderly manner when lifting with two machines; the main crane lowers the steel cage (7) and pours concrete to complete the construction of all ground-connected walls; after the steel cage (7) is lowered into place, the back of the anti-bypass steel plate (8) is promptly backfilled with sandbags (9) in the over-gripping area to reduce the amount of concrete bypass during the pouring process.

2. The method for constructing a stepped terrain high and low-amplitude diaphragm wall according to claim 1, characterized in that: The anti-circumvention steel plate (8) is welded to the prefabricated ground-connected wall reinforcement cage, and its width is smaller than the width of the excavated ground-connected wall groove section, so as to prevent the concrete from overflowing from the gap and circumventing during the pouring process.

3. The method for constructing a stepped terrain high and low-amplitude diaphragm wall according to claim 2, characterized in that: The anti-bypass iron sheets welded on both sides of the anti-bypass steel plate (8) enhance the anti-bypass capability of the concrete.

4. The method for constructing a stepped terrain high and low-amplitude diaphragm wall according to claim 2, characterized in that: The bottom surface position of the anti-circumference steel plate (8) welded and installed is consistent with the top surface height of the low-field flat concrete that has been constructed, ensuring that after the steel cage is hoisted and lowered, the gap between the bottom surface of the anti-circumference steel plate and the top of the low-width ground-connected wall is small, and concrete cannot overflow and circumferentially flow.

5. The method for constructing a stepped terrain high and low-amplitude diaphragm wall according to claim 1, characterized in that: The optimized construction process of the multi-standard high-ground connecting wall on the stepped terrain comprehensively considers the lifting capacity of the crawler crane and the safety operation requirements of the trenching machine near the edge before construction, and plans the slope positions of the steps on the site twice. The first slope reduction can complete the lifting of all the ground connecting walls on the high steps, and the second backfill slope reduction section of the site slope reduction connection section has sufficient edge operating width for the trenching machine to complete the trenching construction, thereby avoiding the crawler crane from climbing back and forth.

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