A cover-excavation construction method for passing under an existing building structure

Abstract

The present invention discloses a cover excavation construction method for passing under an existing building structure, comprising the following steps: constructing a top protective layer and a horizontal water diversion pipe; excavating the upper left and right side guide holes under the supporting structure, constructing retaining piles downward on the sides of the side guide holes, and constructing a crown beam on the upper part of the retaining piles; excavating the upper middle guide hole under the supporting structure; using the crown beam as the two end supports, constructing the first layer of secondary lining along the top inner contour of the supporting structure; using the crown beam as the two end supports, constructing the second layer of secondary lining along the inner contour of the first layer of secondary lining; excavating earthwork downward along the middle, reserving counter-pressure soil on both sides; excavating the earthwork on both sides to the retaining piles to construct an anchoring structure on the side wall; sealing the bottom of the cushion layer, and constructing the bottom plate and side wall. The beneficial effects of the present invention: by carrying out waterproofing and support construction in advance, it is ensured that the upper soil does not settle during the later tunnel excavation, and the retaining piles are used to support the lining structure to ensure the tunnel is stable under stress.

Description

Technical Field

[0001] The invention belongs to the technical field of underground construction, and in particular relates to a cover-and-excavation construction method for passing under an existing building structure. Background Art

[0002] For some composite strata, the precipitation conditions are poor and it is difficult to achieve the drainage and precipitation effect. Water is required during underground excavation, and mud and water gushing are prone to occur on the face. At the same time, there are important buildings above with high protection requirements and the need to reduce settlement as much as possible. Therefore, a construction method that can be safely constructed under such geological conditions is needed. Summary of the invention

[0003] The purpose of the present invention is to provide a cover-and-excavation construction method for underpass existing building structures, thereby solving the problem of tunnel excavation under complex and severe geological conditions.

[0004] The object of the present invention is achieved through the following technical solutions:

[0005] A cover-and-excavation construction method for passing under an existing building structure comprises the following steps:

[0006] Step ①, constructing a top protective layer and a horizontal water diversion pipe, wherein the horizontal water diversion pipe is located on both sides of the top protective layer;

[0007] Step ②, under the supporting structure, excavate the upper left and right side guide holes, and construct the retaining piles downward from the sides of the side guide holes, and construct the crown beam on the upper part of the retaining piles;

[0008] Step ③, under the supporting structure, excavate the upper middle guide tunnel to complete the connection between the side guide tunnels;

[0009] Step ④, using the crown beam as the support at both ends, construct the first layer of secondary lining along the top inner contour of the supporting structure;

[0010] Step ⑤, using the crown beam as the support at both ends, construct the second layer of secondary lining along the inner contour of the first layer of secondary lining;

[0011] Step ⑥, excavate the earth downward along the middle, and reserve counter-pressure soil on both sides;

[0012] Step 7: excavate the earth on both sides to the retaining piles, and then construct the anchor structure on the side wall;

[0013] Step ⑧: seal the bottom of the cushion layer, construct the bottom plate and side walls in sequence to complete the structural construction.

[0014] Furthermore, in the step ①, the top protective layer is a multi-row pipe shed, in the step ②, the side support members are constructed, and in the step ③, the middle support members are constructed between the side support members, and the side support members and the middle support members form a complete inverted U-shaped structure.

[0015] Furthermore, in the step ②, a partition support and a side arch are constructed inside the side guide tunnel, the partition support is vertically supported on the top of the earth to be excavated and the supporting structure, and the side arch is horizontally supported on the side of the earth to be excavated and the supporting structure. In step ⑤, the partition support is removed, and in step ⑥, the side arch is removed.

[0016] Furthermore, in the step ②, embedded steel bars are constructed in the crown beam, and the embedded steel bars are located at the position of the first layer of secondary lining.

[0017] Furthermore, in the step ③, a step higher than the bottom of the side guide tunnel is reserved below the middle guide tunnel.

[0018] Furthermore, in the step ⑤, sand filling is constructed between the earth to be excavated and the second layer of secondary lining.

[0019] Furthermore, in the step ⑥, a slope is constructed on the inner side of the counter-pressure soil.

[0020] Furthermore, in the step ⑦, anchor rods are constructed on the side walls.

[0021] Furthermore, in step ⑧, the side walls support both ends of the second layer of secondary lining.

[0022] The beneficial effects of the present invention are as follows: by carrying out waterproofing and supporting construction in advance, it is ensured that the upper soil does not settle during the later tunnel excavation, and the lining structure is supported by retaining piles to ensure the tunnel is stable under stress.

[0023] The aforementioned main scheme of the present invention and its further options can be freely combined to form multiple schemes, all of which are schemes that can be adopted and claimed for protection by the present invention; and in the present invention, (non-conflicting options) options and other options can also be freely combined. After understanding the scheme of the present invention, those skilled in the art can understand that there are many combinations based on the prior art and common knowledge, all of which are technical schemes to be protected by the present invention, and they are not exhaustively listed here. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a construction schematic diagram of the present invention.

[0025] In the figure: 1-top protective layer, 2-horizontal water diversion pipe, 4-side guide hole, 5-middle partition support, 6-side invert arch, 7-middle guide hole, 8-step, 9-guard piles, 10-crown beam, 11-embedded steel bars, 12-first layer secondary lining, 13-second layer secondary lining, 14-sand filling, 15-counter pressure soil, 16-anchor rod, 17-bottom plate, 18-side wall, 301-side support, 302-middle support. DETAILED DESCRIPTION

[0026] The following non-limiting examples serve to illustrate the invention.

[0027] Embodiment 1:

[0028] refer to Figure 1 As shown, a cover-and-excavation construction method for passing under an existing building structure comprises the following steps:

[0029] Step ①, construct a top protective layer 1 and a horizontal water diversion pipe 2. The top protective layer 1 is a multi-row pipe rack used to protect and waterproof the top. The horizontal water diversion pipe 2 is located on both sides of the top protective layer 1 and is used to drain the accumulated water gathered on both sides of the top protective layer 1.

[0030] Step ②, construct side support members 301, under the support of the side support members 301, excavate the upper left and right side guide tunnels 4, construct the middle partition support members 5 and the side arches 6 inside the side guide tunnels, the middle partition support members 5 are vertically supported on the top of the earth to be excavated and the side support members 301, and the side arches 6 are horizontally supported on the sides of the earth to be excavated and the side support members 301, so as to support the inside of the guide tunnel.

[0031] Retaining piles 9 are constructed downwardly from the side of the side guide tunnel 4, a cap beam 10 is constructed on the upper part of the retaining piles 9, embedded steel bars 11 are constructed in the cap beam 10, the cap beam 10 is used to support the secondary lining structure, and the retaining piles 9 are used to support the cap beam 10.

[0032] Step ③, construct the middle support member 302 between the side support members 301, the side support members 301 and the middle support member 302 form a complete inverted U-shaped structure, and under the support of the middle support member 302, excavate the upper middle guide tunnel 7 to complete the connection between the side guide tunnels 4. Leave a step 8 higher than the bottom of the side guide tunnel 4 below the middle guide tunnel 7 to ensure the normal support of the middle support member 5 and the side invert 6.

[0033] Step ④, with the crown beam 10 as the two end supports, construct the first layer of secondary lining 12 along the top inner contour of the support structure, insert the embedded steel bars 11 into the first layer of secondary lining 12 to improve the connection strength, and retain the middle partition support 5 and the side arch 6.

[0034] Step ⑤, remove the middle partition support 5, use the crown beam 10 as the two end supports, construct the second secondary lining 13 along the inner contour of the first secondary lining 12, and construct sand filling 14 between the earth to be excavated and the second secondary lining 13 for temporary support.

[0035] Step ⑥, remove the side inverted arch 6, excavate the earth downward along the middle, reserve counter-pressure soil 15 on both sides, and construct a slope on the inner side of the counter-pressure soil 15 to form a counter-pressure force and avoid landslides.

[0036] Step ⑦, excavate the earth on both sides to the retaining piles 9, and then construct anchor rods 16 on the side walls.

[0037] Step ⑧, the cushion layer is sealed, and the bottom plate 17 and the side wall 18 are constructed in sequence. The side wall 18 supports both ends of the second layer of secondary lining 13 to complete the structural construction.

[0038] The above basic examples of the present invention and their further optional examples can be freely combined to form multiple embodiments, all of which are embodiments that can be adopted and claimed for protection by the present invention. In the scheme of the present invention, each optional example can be arbitrarily combined with any other basic examples and optional examples.

[0039] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A cover-and-excavation construction method for underpass existing building structures, characterized in that: The steps include: Step ①, constructing a top protective layer (1) and a horizontal water diversion pipe (2), wherein the horizontal water diversion pipe (2) is located on both sides of the top protective layer (1); Step ②, under the supporting structure, excavate the upper left and right side guide holes (4), and construct the retaining piles (9) downward from the sides of the side guide holes (4), and construct the crown beams (10) on the upper parts of the retaining piles (9); Step ③, excavating the upper middle guide tunnel (7) under the supporting structure to complete the connection between the side guide tunnels (4); Step ④, using the crown beam (10) as the two end supports, constructing the first layer of secondary lining (12) along the top inner contour of the supporting structure; Step ⑤, using the crown beam (10) as the two end supports, construct the second layer of secondary lining (13) along the inner contour of the first layer of secondary lining (12); Step ⑥, excavating the earth downward from the middle, and reserving counter-pressure soil on both sides (15); Step ⑦, excavate the earth on both sides to the retaining piles (9), and then construct anchor structures on the side walls; Step ⑧, the cushion layer is sealed, and the bottom plate (17) and the side wall (18) are constructed in sequence to complete the structural construction.

2. The cover-excavation construction method for passing under an existing building structure according to claim 1 is characterized in that: In the step ①, the top protective layer (1) is a multi-row pipe shed, in the step ②, the side support members (301) are constructed, and in the step ③, the middle support members (302) are constructed between the side support members (301), and the side support members (301) and the middle support members (302) form a complete inverted U-shaped structure.

3. The cover-excavation construction method for passing under an existing building structure according to claim 1 or 2, characterized in that: In the step ②, a middle partition support member (5) and a side inverted arch (6) are constructed inside the side guide tunnel, the middle partition support member (5) is vertically supported on the top of the earth to be excavated and the supporting structure, and the side inverted arch (6) is horizontally supported on the side of the earth to be excavated and the supporting structure. In step ⑤, the middle partition support member (5) is removed, and in step ⑥, the side inverted arch (6) is removed.

4. The cover-excavation construction method for passing under an existing building structure according to claim 1 is characterized in that: In the step ②, embedded steel bars (11) are constructed in the crown beam (10), and the embedded steel bars (11) are located at the position of the first layer of secondary lining (12).

5. The cover-and-excavation construction method for passing under an existing building structure according to claim 1 is characterized in that: In the step ③, a step (8) higher than the bottom of the side guide hole (4) is reserved below the middle guide hole (7).

6. The cover-and-excavation construction method for passing under an existing building structure according to claim 1 is characterized in that: In the step ⑤, sand filling (14) is constructed between the earth to be excavated and the second layer of secondary lining (13).

7. The cover-and-excavation construction method for passing under an existing building structure according to claim 1 is characterized in that: In the step ⑥, a slope is constructed on the inner side of the counter pressure soil (15).

8. The cover-excavation construction method for passing under an existing building structure according to claim 1 is characterized in that: In the step ⑦, anchor rods (16) are constructed on the side wall.

9. The cover-excavation construction method for passing under an existing building structure according to claim 1 is characterized in that: In the step ⑧, the side wall (18) supports both ends of the second layer of secondary lining (13).

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