Underground passage open excavation connection construction method under high water level condition

Abstract

According to the underground passage open excavation connection construction method under the high water level condition, a connection opening which is communicated with an existing underground space and used for being connected with a newly-built underground passage is constructed on the side, relative to the design position of the newly-built underground passage, of the existing underground space, and the method comprises the following steps that S1, pipeline distribution and the underground water level at the construction position of the connection opening are ascertained, and a precipitation well is constructed; s2, a foundation pit support is constructed at the connection opening according to planning; s3, foundation pit excavation is conducted on the connection opening, and an inner support is constructed; s4, a support on the side, close to the connection opening, of the existing underground space is additionally reinforced, and excavation continues; and S5, existing supports and side walls are broken, the existing underground space communicates with the connection opening, and the waterproof curtain is reserved. The underground water level and the pipeline distribution condition at the connection opening are detected before construction, the influence of construction on existing pipelines is reduced, a waterproof curtain of an existing underground space is reserved, the influence of the high water level on construction is effectively reduced, an existing structure is utilized, the cost can be saved, the construction period is shortened, and good economic benefits are achieved.

Description

Technical Field

[0001] The invention relates to the technical field of building construction, and in particular to an open-cut connection construction method for an underground passage under high water level conditions. Background Art

[0002] In the process of promoting the construction of urban public infrastructure, the connection technology between the new underground space and the existing space has become a key technical issue. When the existing technology is used for underground passage connection construction, it is often difficult to ensure the waterproof quality of the connection construction, the construction is slow, and it is unsafe and environmentally unfriendly due to factors such as high groundwater levels, complex pipelines, and proximity to important projects. Summary of the invention

[0003] The present application provides an open-cut connection construction method for underground passages under high water level conditions. By exploring the groundwater level and pipeline distribution in advance, setting up precipitation wells and retaining the waterproof curtain of the existing underground space, the waterproof quality of the connection port under high water level conditions is ensured, and the impact of existing pipelines and high water levels on construction is effectively reduced.

[0004] The present invention provides an open-cut connection construction method for underground passages under high water level conditions.

[0005] A method for open-cut connection of underground passages under high water level conditions, comprising constructing a connection port connected to the existing underground space on one side of the existing underground space relative to the design position of the new underground passage for connection with the new underground passage, comprising the following steps:

[0006] S1. Find out the pipeline distribution and groundwater level at the construction site of the connection port, plan the construction of the connection port according to the results of the exploration, and construct a dewatering well outside the construction site of the connection port;

[0007] S2. Construct foundation pit support at the connection port construction site according to the plan;

[0008] S3, excavating a foundation pit at the connection port, constructing internal supports between the foundation pit supports on both sides during the excavation process until the excavation reaches the top elevation of the existing underground space;

[0009] S4, additionally reinforcing the existing support on one side of the existing underground space close to the connection port, and continuing to excavate the foundation pit until the excavation reaches the bottom elevation of the existing underground space and the existing support is exposed;

[0010] S5. Remove the existing support and side walls, connect the existing underground space with the connection port, and retain the water-stop curtain of the existing underground space after removal.

[0011] A further improvement of the present invention is that, before executing step S2, it is determined whether there is a water supply pipe in the pipeline at the connection port. If there is a water supply pipe, the water supply pipe should be avoided during the construction of the foundation pit support, and the foundation pit should be reinforced at the water supply pipe by spray anchoring, and other pipelines except the water supply pipe should be moved in advance to outside the connection port construction site.

[0012] A further improvement of the present invention is that when the foundation pit is excavated and the water supply pipe is exposed, the water supply pipe is protected. The specific steps are: a steel frame is spanned between the crown beams of the foundation pit supports on both sides of the connection port, ensuring that the steel frame is set above the water supply pipe, and the water supply pipe and the steel frame are bundled and lifted.

[0013] A further improvement of the present invention is that, when excavating the foundation pit, a layered excavation method is adopted, and each time a layer is excavated, the internal support is constructed between the foundation pit supports of that layer.

[0014] A further improvement of the present invention is that the additional reinforcement of the existing support on one side of the existing underground space close to the connection port in step S4 specifically includes the following steps:

[0015] S41. Slope the existing upper soil support, set soil nails on the slope, set drainage holes, and then hang a net for spraying;

[0016] S42, chiseling the support piles of the existing support to a certain depth, and inserting and tying the rear waist beams at the chiseled positions of the support piles.

[0017] A further improvement of the present invention is that after the existing support is removed, a drainage well is opened in the connection pit, a drainage ditch is fixed between the support piles of the existing support and the side wall of the existing underground space, and the drainage ditch is connected to the drainage well.

[0018] A further improvement of the present invention is that after the existing underground space and the connection port are connected, a new underground passage is constructed on the side of the connection port facing away from the existing underground space, and the new underground passage is waterproofed.

[0019] A further improvement of the present invention is that, when the side walls and existing supports of the existing underground space are removed and waterproofing construction is carried out on the newly built underground passage, the water-stop curtain is overlapped with the waterproof structure of the newly built underground passage.

[0020] The present invention minimizes the impact of construction on existing pipelines by exploring the groundwater level and pipeline distribution at the connection point before construction, retains the water-stop curtain of the existing underground space, effectively reduces the impact of high water levels on construction, and utilizes the existing structure to save costs, shorten construction period, and has good economic benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a schematic diagram of the trench before excavation at the connection point of the present invention;

[0022] Figure 2 This is a schematic diagram of the dewatering well and support construction at the connection point of the present invention;

[0023] Figure 3 This is a schematic diagram of the first layer of earthwork excavation for the foundation pit at the connection point of the present invention;

[0024] Figure 4 This is a schematic diagram of the foundation pit after multi-layer excavation at the connection point of the present invention;

[0025] Figure 5 This is a schematic diagram of the layered construction of the foundation pit at the connection point of the present invention;

[0026] Figure 6 It is a schematic diagram of the existing underground space support pile cutting of the present invention;

[0027] Figure 7 It is a schematic diagram of temporary closure before the side wall of the existing underground space of the present invention is broken;

[0028] Figure 8 This is a schematic diagram of breaking down the existing side wall of the underground space of the present invention;

[0029] In the figure: 1. exploration trench; 2. foundation pit support; 3. dewatering well; 4. crown beam; 5. steel frame; 6. water supply pipe; 7. internal support; 8. existing support; 9. rear cross beam; 10. existing underground space side wall; 11. waterproof cloth; 121. first waterproof sill; 122. second waterproof sill; 13. sealing plate; 14. side wall opening; 15. cloth belt. DETAILED DESCRIPTION

[0030] like Figures 1 to 8 As shown, an open-cut connection construction method for underground passages under high water level conditions is provided, wherein a connection port connected to the existing underground space for connection to the new underground passage is constructed on one side of the existing underground space relative to the design position of the new underground passage, and includes the following steps:

[0031] S1, finding out the pipeline distribution and groundwater level at the construction site of the connection port, and planning the construction of the connection port according to the results of the exploration to avoid the pipeline, and constructing a dewatering well 3 outside the construction site of the connection port according to the distribution of underground pipelines or groundwater level found;

[0032] S2. Construct foundation pit support 2 at the construction site at the connection port according to the plan;

[0033] S3, excavate the foundation pit at the docking port, and construct internal supports between the foundation pit supports 2 on both sides during the excavation process until the excavation reaches the top elevation of the existing underground space;

[0034] S4, additionally reinforcing the existing support 8 on the side of the existing underground space close to the connection port, and continuing to excavate the foundation pit until the excavation reaches the bottom elevation of the existing underground space and the existing support 8 is exposed;

[0035] S5. Remove the existing support 8 and the existing underground space side wall 10, connect the existing underground space and the connection port, and retain the water-stop curtain of the existing underground space after removal.

[0036] Preferably, if Figure 3 As shown, before executing step S2, determine whether there is a water supply pipe 6 in the pipeline at the connection port. If there is a water supply pipe 6, the water supply pipe 6 should be avoided during the construction of the foundation pit support, and the foundation pit should be reinforced at the water supply pipe 6 by spray anchoring, and other pipelines except the water supply pipe 6 should be moved in advance to outside the connection port construction site.

[0037] Preferably, if Figure 3 As shown, when the foundation pit is excavated and the water supply pipe is exposed, the water supply pipe 6 is protected. The specific steps are: the steel frame 5 is spanned between the crown beams 4 on both sides of the foundation pit support 2, ensuring that the steel frame 5 is set above the water supply pipe 6, and the water supply pipe 6 and the steel frame 5 are tied and lifted to prevent the water supply pipe 6 from being damaged due to excessive deflection.

[0038] Preferably, in this embodiment, if Figure 3 As shown, the water supply pipe 6 is tied and pulled to the steel frame 5 using a cloth belt 15.

[0039] Preferably, if Figures 4-5 As shown, when excavating the foundation pit, a layered excavation method is adopted, and each layer is excavated with support 7 inside the construction layer.

[0040] Preferably, in this embodiment, during earth excavation, the ground objects or underground objects that hinder the development of the project or affect the stability of the project are relocated and cleared (including pipelines, electric poles, trees, etc., and the pipelines and electric poles need to be removed by contacting Party A), and the vegetation is transported by excavators and bulldozers in conjunction with dump trucks. The excavation is from top to bottom, and the trees, plants, roots and other debris and the surface humus are first removed and discarded. When the bulldozer is clearing the surface, it should be noted that the depth of the shovel blade should be controlled to be able to remove the surface humus, but not too deep. When using an excavator for excavation, a 1:1 slope is set in the direction of the new lower connecting channel during the excavation process. After excavation, the slope and base are repaired manually, and the construction shall not be carried out by a one-time excavation method.

[0041] Preferably, in this embodiment, the inner support 7 is interspersed with the layered excavation of the earthwork, the first layer on the top is a concrete support, and the lower part is a steel support. The design of the construction concrete steel support structure adopts one end as a fixed end and the other end as a movable end, and the butt joint extension of the steel pipe adopts a flange connection. The connection between the movable end and the steel pipe is connected by a flange. In addition to the processing of standard lengths, short sections of steel pipes of different lengths are equipped to adapt to the changes in cross-sectional width and diagonal bracing length requirements caused by construction deviations in the foundation pit. The standard section of the steel pipe is processed in the factory, and the rest is processed and spliced ​​on site. The steel waist beam is processed and welded in sections on site, and assembled and welded into one in the foundation pit during installation. The on-site processed steel waist beam is inspected and accepted in accordance with the steel structure construction acceptance specifications.

[0042] Preferably, if Figure 6 As shown, in step S4, additional reinforcement of the existing support 8 near the connection port specifically includes the following steps:

[0043] S41, slope the upper part of the existing support 8, set soil nails on the slope, set drainage holes and then hang a net for spraying;

[0044] S42, chiseling the support piles of the existing support 8 to a certain depth, and inserting and binding the rear waist beam 9 at the chiseled support piles of the existing support 8.

[0045] Preferably, after removing the existing support 8, a drainage well is opened in the foundation pit at the connection port, a drainage ditch is fixed between the existing support 8 and the existing underground space side wall 10, the drainage ditch is connected to the drainage well, and the water is pumped out of the foundation pit by a water pump.

[0046] Preferably, in this embodiment, the supporting piles of the existing support 8 are cut by a rope saw, and the cut piles are cut and chiseled in two sections, about 2 meters each section. The erection of the frame must meet the installation height requirement of the rope saw. Since the piles are dismantled and returned to the top one by one, the frame needs to be dismantled and erected multiple times.

[0047] The cutting seam of the pile cutting rope saw should be set to be inclined upward. Before cutting, two pull rings are welded on the main reinforcement of the support pile to be cut. Through the hand winch + iron chain, one end passes through the pull ring, and the other end is pulled upward and fixed on the support on the support pile. The cut part after the pile cutting is lifted out through the hand winch. Finally, the pulled pile head is lifted out of the foundation pit by a crane; according to this step, the existing support piles 8 at the interface are removed one by one in sections.

[0048] Preferably, if Figure 7As shown, before the existing underground space side wall 10 is demolished, it is temporarily closed, and a blocking plate 13 is set on the side close to the original underground space for blocking. At the same time, an advertising cloth is hung on the blocking plate 13, and the side of the blocking plate 13 close to the underground space side wall 10 is covered with a waterproof cloth 11. A first water retaining ridge 121 is set near the opening position for water blocking, and a second water retaining ridge 122 is set near the closed position, and the surface is plastered with waterproof mortar.

[0049] Preferably, in this embodiment, the specific steps of demolishing the existing underground space side wall 10 include: during work, the top plate of the adjacent passage in the renovation area is supported, the beam plate is tightened, and the existing underground space side wall 10 can be demolished only after the full unloading is completed. The replacement support frame adopts a steel pipe frame, and scissor braces are set on the four sides of the frame. A scissor brace is set along the longitudinal direction every four rows of vertical poles in the middle, and horizontal scissor braces are set. The scissor braces should be set continuously from bottom to top;

[0050] After measuring and locating the demolished part of the existing underground space side wall 10, the boundary line of the demolished part is clearly marked on the underground space side wall 10 with red paint, the cutting line is applied, the water drill is used to drill holes, and the rope saw chain is threaded to divide the blocks. Expansion screws are installed at appropriate positions on the wall to fix the cutting machine and the guide wheel, and cutting begins.

[0051] Preferably, in this embodiment, when demolishing the existing underground space side wall 10, waste tires of the same height as the cut side wall soil blocks are placed outside the original underground space side wall as buffer materials, and the surface protective layer of the side wall soil blocks is chiseled off to expose the steel bars, and then the concrete blocks are pulled out by hand winches, dropped on the buffer pad, and slowly placed on the ground. It is strictly forbidden to pull out the concrete blocks directly and drop them on the floor to cause impact. Finally, the reserved steel bar section wall is chiseled out with a pneumatic pick, and the line is positioned before chiseling. The chiseling is carried out from top to bottom to prevent cross-operation.

[0052] Preferably, after the existing underground space and the connection port are connected, a new underground passage is constructed on the other side of the connection port, and waterproofing construction is performed on the new underground passage.

[0053] Preferably, in this embodiment, when waterproofing the newly built underground passage, waterproof coating and waterproof membrane are used for waterproofing the outer structure of the newly built underground passage, and when the existing underground space side wall 10 is demolished, at least 200mm of the existing underground space structure waterproof membrane is reserved to facilitate the overlap of the waterproofing of the newly built underground passage. At the same time, auxiliary tools for waterproof membrane are used during construction to ensure the quality of membrane construction.

[0054] During the construction process, waterproof construction must be carried out strictly in accordance with the design requirements. The construction joints at the interface between the new underground passage structure and the connection port need to be pre-buried with waterstop strips, waterstop tapes and full-section grouting pipes to enhance the waterproof effect of the construction joints and facilitate subsequent plugging. At the same time, drainage ditches and water boxes must be set up as required.

[0055] Preferably, after demolishing the existing underground space side wall 10 and the existing support 8, a section of the existing underground space waterproof material is retained, and when waterproofing construction is carried out on the new underground passage, the waterproof material is overlapped with the waterproof structure of the new underground passage.

[0056] Finally, it should be noted that the above are only preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments, or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for connecting an underground passage under high water level conditions, wherein a connection port connected to the existing underground space for connecting the new underground passage is constructed on one side of the existing underground space relative to the design position of the new underground passage, and characterized in that: The following steps are involved: S1. Find out the pipeline distribution and groundwater level at the construction site of the connection port, plan the construction of the connection port according to the results of the exploration, and construct a dewatering well outside the construction site of the connection port; S2. Construct foundation pit support at the connection port construction site according to the plan; S3, excavating a foundation pit at the connection port, constructing internal supports between the foundation pit supports on both sides during the excavation process until the excavation reaches the top elevation of the existing underground space; S4, additionally reinforcing the existing support on one side of the existing underground space close to the connection port, and continuing to excavate the foundation pit until the excavation reaches the bottom elevation of the existing underground space and the existing support is exposed; S5. Remove the existing support and side walls, connect the existing underground space with the connection port, and retain the water-stop curtain of the existing underground space after removal.

2. The open-cut connection construction method for underground passages under high water level conditions as claimed in claim 1, characterized in that: Before executing step S2, determine whether there is a water supply pipe at the connection port. If there is a water supply pipe, the water supply pipe should be avoided during the construction of the foundation pit support, and the foundation pit should be reinforced at the water supply pipe by spray anchoring, and other pipelines except the water supply pipe should be moved to the outside of the connection port construction site in advance.

3. The open-cut connection construction method for underground passages under high water level conditions as claimed in claim 2, characterized in that: When the foundation pit is excavated and the water supply pipe is exposed, the water supply pipe is protected. The specific steps are: a steel frame is spanned between the crown beams of the foundation pit supports on both sides of the connection port, ensuring that the steel frame is set above the water supply pipe, and the water supply pipe and the steel frame are bundled and lifted.

4. The open-cut connection construction method for underground passages under high water level conditions as claimed in claim 1, characterized in that: When excavating the foundation pit, a layered excavation method is adopted, and each time a layer is excavated, the internal support is constructed between the foundation pit supports of that layer.

5. The open-cut connection construction method for underground passages under high water level conditions as claimed in claim 1, characterized in that: In step S4, additional reinforcement of the existing support on one side of the existing underground space close to the connection port specifically includes the following steps: S41, slope the upper earthwork of the existing support, set soil nails on the slope, set drainage holes, and then hang a net for spraying; S42, chiseling the support piles of the existing support to a certain depth, and inserting and tying the rear waist beams at the chiseled positions of the support piles.

6. The open-cut connection construction method for underground passages under high water level conditions as claimed in claim 1, characterized in that: After removing the existing support, a drainage well is opened in the foundation pit of the connection port, a drainage ditch is fixed between the support piles of the existing support and the side wall of the existing underground space, and the drainage ditch is connected to the drainage well.

7. The open-cut connection construction method for underground passages under high water level conditions as claimed in claim 1, characterized in that: After the existing underground space and the connection port are connected, a new underground passage is constructed on the side of the connection port facing away from the existing underground space, and waterproofing construction is performed on the new underground passage.

8. The open-cut connection construction method for underground passages under high water level conditions as claimed in claim 7, characterized in that: When waterproofing the newly built underground passage, the water-stop curtain is overlapped with the waterproof structure of the newly built underground passage.

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