Open cut foundation pit temporary cover plate supporting structure and construction method

Abstract

The invention relates to the technical field of building construction, in particular to an open cut foundation pit temporary cover plate supporting structure. The temporary cover plate supporting structure for the open cut foundation pit specifically comprises fender posts, a top beam and a supporting wall body, the top beam is fixedly arranged above the fender posts, the supporting wall body is fixedly arranged above the top beam, and the temporary cover plate covers the supporting wall body; the supporting wall body comprises longitudinal load-bearing steel bars, transverse distribution steel bars and tie bars, and the longitudinal load-bearing steel bars are perpendicular to the transverse distribution steel bars and connected with the transverse distribution steel bars through the tie bars; the top beam comprises reserved joint bars and a plurality of grooves, the reserved joint bars are fixedly connected with the transversely-distributed steel bars, and the supporting wall body partially permeates into the grooves; the longitudinal load-bearing steel bars, the transverse distribution steel bars and the reserved joint bars are all glass fiber bars. The invention has the advantages of meeting the requirements of grounds with various gradients and being easy to chisel and cut in the later period.

Description

Technical Field

[0001] The invention relates to the technical field of building construction, and in particular to a temporary cover plate supporting structure for an open excavation foundation pit and a construction method thereof. Background Art

[0002] Subways are usually laid along municipal roads, and foundation pit excavation is an important part of engineering construction. During construction, in order to ensure road access, it is necessary to lay a temporary concrete cover above the foundation pit, which not only facilitates the passage of surrounding residents and construction vehicles, but also provides conditions for station construction. Generally, both ends of the temporary concrete cover of the station foundation pit are supported above the crown beam, and lattice columns and connecting beams are set under the temporary cover to support the temporary cover, ensuring the safety and stability of the temporary cover.

[0003] In traditional temporary cover construction, both ends of the temporary concrete cover are directly supported on the top of the crown beam, and the crown beam on the top of the retaining pile needs to be close to the road surface. The main construction disadvantages are as follows: (1) The top elevation of the crown beam should be close to the ground. When the ground slope is large, the retaining pile and the crown beam need to slope with the ground slope, which is difficult to construct and easy to cause noise and pollution; (2) The crown beam has completely invaded the pavement structure layer. After the station construction is completed, the crown beam needs to be chiseled out before the road is restored. The construction progress of the crown beam chiseling is slow and has a great impact on the surrounding environment; (3) Because the crown beam contains steel bars, its hardness is higher, and it takes more force and time to chisel and cut it.

[0004] Sometimes, in order to meet deadlines, on-site construction units directly cast the pavement structure layer on the temporary concrete cover, which causes adverse effects: (1) The temporary cover is too large to fill the backfill soil densely, which can easily cause voids in the temporary cover. (2) The pavement structure layer is directly cast on the top of the temporary cover. The elevation of the pavement on the temporary cover is significantly higher than the elevation of the surrounding roads, making it more difficult to connect with the surrounding roads. Later, vehicles will experience severe bumps during driving, which can easily cause traffic accidents. (3) The temporary concrete cover and crown beam are close to the ground, which increases the difficulty of later road reconstruction and pipeline relocation.

[0005] Therefore, in view of the deficiencies in the prior art, a temporary cover support structure for an open excavation foundation pit is provided. Summary of the invention

[0006] In order to overcome the shortcomings of the prior art, the present invention provides a temporary cover plate support structure for an open excavation foundation pit, aiming to solve the problem that it is not suitable for ground with a large slope and is difficult to chisel and cut later.

[0007] In order to achieve the above object, the present invention adopts the following technical solutions:

[0008] A temporary cover support structure for an open excavation foundation pit, comprising: retaining piles, a crown beam and a supporting wall;

[0009] The crown beam is fixedly arranged above the retaining pile, the supporting wall is fixedly arranged above the crown beam, and a temporary cover plate is arranged on the supporting wall;

[0010] The supporting wall comprises longitudinal stress-bearing steel bars, transverse distribution steel bars and tension bars, wherein the longitudinal stress-bearing steel bars and the transverse distribution steel bars are arranged vertically, and the longitudinal stress-bearing steel bars and the transverse distribution steel bars are connected by the tension bars;

[0011] The cap beam includes a reserved dowel bar and a plurality of grooves, the reserved dowel bar is fixedly connected to the transversely distributed steel bars, and the supporting wall partly penetrates into the plurality of grooves;

[0012] The longitudinal force-bearing steel bars, the transverse distribution steel bars and the reserved dowel bars are all glass fiber bars.

[0013] As a further improvement of the technical solution of the present invention, the longitudinal force-bearing steel bar includes a first steel bar and a second steel bar, the first steel bar and the second steel bar are anchored to each other, the length of one end of the first steel bar extending into the second steel bar is 1 / 3, and the length of one end of the second steel bar extending into the first steel bar is 1 / 3.

[0014] As a further improvement of the technical solution of the present invention, the length of the transverse distributed steel bars anchored in the crown beam is not less than 1.5 times the tensile anchoring length and not less than 40 times the diameter of the longitudinal force-bearing steel bars.

[0015] As a further improvement of the technical solution of the present invention, the thickness of the supporting wall is 300mm-800mm.

[0016] As a further improvement of the technical solution of the present invention, it also includes a first support and a plurality of second supports, wherein the first support is located between adjacent crown beams, and the second support is located between adjacent retaining piles.

[0017] As a further improvement of the technical solution of the present invention, it also includes a lattice column and a longitudinal connecting beam, the longitudinal connecting beam is fixedly arranged above the lattice column, the lattice column supports the longitudinal connecting beam, a temporary cover plate is covered on the connecting beam, and the second support is connected to the lattice column.

[0018] As a further improvement of the technical solution of the present invention, the lattice columns and the longitudinal connecting beams are located at the center line of the road.

[0019] A construction method for a temporary cover plate support structure for an open excavation foundation pit, applicable to the above-mentioned temporary cover plate support structure for an open excavation foundation pit, comprises the following steps:

[0020] S1: Foundation construction: construct retaining piles. After the construction is completed, the pile heads will be chiseled off and the cap beam will be constructed;

[0021] S2: Treat the crown beam: reserve dowel bars on the crown beam, roughen the surface of the crown beam to form several grooves, clean the grooves and apply an interface treatment agent on the groove interface;

[0022] S3: Construction of supporting wall: connecting the reserved dowel bars with the transverse distribution steel bars, connecting the longitudinal force-bearing steel bars with the transverse distribution steel bars through the tie bars, supporting the formwork and pouring the concrete, and the concrete seeping into the groove;

[0023] S4: Construction of temporary cover: cast-in-place steel slow-setting soil and paving asphalt on top;

[0024] S4: Chisel away the supporting structure: After the station construction is completed, the supporting walls and temporary cover plates are cut statically.

[0025] As a further improvement of the technical solution of the present invention, in step S2: the depth of the grooves is not less than 40 mm, and the spacing between the grooves is not greater than 150 mm.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] In the temporary cover support structure of the open-cut foundation pit of the present invention, a support wall is arranged on the crown beam, and the height of the support wall is adjusted according to the ground slope to meet the requirements of various ground slopes. Dowel bars and grooves are reserved on the crown beam, and the reserved dowel bars are fixedly connected to the transverse distribution steel bars of the support wall. The transverse distribution steel bars are connected to the longitudinal force-bearing steel bars through tension bars. When the support wall is cast, part of the support wall penetrates into the groove, so that the support wall is tightly connected to the crown beam. Since the longitudinal force-bearing steel bars, the transverse distribution steel bars and the reserved dowel bars are all glass fiber bars, and since the glass fiber bars have high tensile strength and low shear strength, after the construction of the station is completed, the temporary cover and the support wall can be directly cut and removed by static cutting without chiseling out the crown beam, thereby ensuring the safety of the wall structure. The temporary cover support structure of the open-cut foundation pit has the characteristics of meeting the requirements of various ground slopes and being easy to chisel out and cut in the later stage. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The technology of the present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments:

[0029] Figure 1 It is a structural schematic diagram of a temporary cover plate support structure for an open excavation foundation pit according to the present invention;

[0030] Figure 2 It is a top view of the temporary cover plate supporting structure of the open excavation foundation pit of the present invention.

[0031] In the figure:

[0032] 1. Guard piles;

[0033] 2. Crown beam;

[0034] 3. Support wall; 31. Longitudinal force-bearing steel bars; 311. First steel bars; 312. Second steel bars; 32. Transverse distribution steel bars; 33. Tension bars;

[0035] 41. First support; 42. Several second supports;

[0036] 51. Lattice column; 52. Longitudinal connecting beam;

[0037] 6. Temporary cover. DETAILED DESCRIPTION

[0038] The following will be combined with the embodiments and drawings to clearly and completely describe the concept, specific structure and technical effects of the present invention, so as to fully understand the purpose, scheme and effect of the present invention. It should be noted that the embodiments in this application and the features in the embodiments can be combined with each other without conflict. The same reference numerals used throughout the drawings indicate the same or similar parts.

[0039] It should be noted that, unless otherwise specified, when a feature is referred to as being "fixed" or "connected" to another feature, it may be directly fixed or connected to the other feature, or it may be indirectly fixed or connected to the other feature. In addition, the descriptions of up, down, left, right, etc. used in the present invention are only relative to the relative positional relationship of the components of the present invention in the drawings.

[0040] Reference Figure 1 to Figure 2 , a temporary cover plate 6 supporting structure of an open excavation foundation pit, comprising a retaining pile 1, a crown beam 2 and a supporting wall 3;

[0041] In one embodiment, the crown beam 2 is fixed on the top of the retaining pile 1, the supporting wall 3 is fixed on the crown beam 2, the temporary cover 6 is covered on the supporting wall 3, and the supporting wall 3 is used to support the temporary cover 6; the supporting wall 3 includes longitudinal stress-bearing steel bars 31, transverse distribution steel bars 32 and tie bars 33, the longitudinal stress-bearing steel bars 31 and the transverse distribution steel bars 32 are vertically arranged, and the longitudinal stress-bearing steel bars 31 and the transverse distribution steel bars 32 are connected by tie bars 33; the crown beam 2 includes reserved dowel bars and a plurality of grooves, the reserved dowel bars are fixedly connected with the transverse distribution steel bars 32, and the supporting wall 3 partially penetrates into the plurality of grooves; the longitudinal stress-bearing steel bars 31, the transverse distribution steel bars 32 and the reserved dowel bars are all glass fiber bars. Preferably, the thickness of the supporting wall 3 is 500 mm, the supporting wall 3 carries the temporary cover 6, and is mainly subjected to bending and compression, with a small shear force, and the glass fiber bars have a high tensile strength and a low shear strength, are not easy to rust, and are easier to cut than steel bars.

[0042] In one embodiment, due to the supporting wall 3, the retaining piles 1 do not need to extend to the ground according to the slope of the ground. By adjusting the height of the supporting wall 3 on the crown beam 2, the temporary cover 6 is connected with the elevation of the surrounding roads, and the environmental adaptability is strong, avoiding construction inconveniences caused by excessive ground slope and a large number of pile types; at the same time, the length of the retaining piles 1 is reduced, saving engineering costs.

[0043] Among them, a supporting wall 3 is arranged on the crown beam 2, and the height of the supporting wall 3 is adjusted according to the ground slope to meet the requirements of various slopes of the ground. Dowel bars and grooves are reserved on the crown beam 2, and the reserved dowel bars are fixedly connected to the transverse distribution steel bars 32 of the supporting wall 3. The transverse distribution steel bars 32 are connected to the longitudinal force-bearing steel bars 31 through the tension bars 33. When the supporting wall 3 is cast, part of the supporting wall 3 penetrates into the groove, so that the supporting wall 3 is tightly connected to the crown beam 2. Since the longitudinal force-bearing steel bars 31, the transverse distribution steel bars 32 and the reserved dowel bars are all glass fiber bars, and since the glass fiber bars have high tensile strength and low shear strength, after the construction of the station is completed, the temporary cover plate 6 and the supporting wall 3 can be directly cut and removed by static cutting without chiseling the crown beam 2, thereby ensuring the safety of the wall structure. The temporary cover plate 6 support structure of the open excavation foundation pit has the characteristics of meeting the requirements of various slopes of the ground and being easy to chisel and cut in the later stage. The support structure simplifies the construction process, reduces the length of the retaining pile 1, saves construction costs, shortens the construction period, and avoids adverse effects such as increased construction difficulty and noise pollution caused by chiseling out the crown beam 2.

[0044] In one embodiment, referring to Figure 2 As shown, the longitudinal force-bearing steel bar 31 includes a first steel bar 311 and a second steel bar 312. The first steel bar 311 and the second steel bar 312 are mutually anchored. One end of the first steel bar 311 extends into the second steel bar 312 by 1 / 3 of the length, and one end of the second steel bar 312 extends into the first steel bar 311 by 1 / 3 of the length.

[0045] In one embodiment, the length of the transverse distribution steel bars 32 anchored in the cap beam 2 is not less than 1.5 times the tensile anchoring length and not less than 40 times the diameter of the longitudinal force steel bars 31. The steel bars are firmly fixed in the concrete to withstand the tensile load and ensure the stability and safety of the structure.

[0046] In one embodiment, the support structure further includes a first support 41 and a plurality of second supports 42 . The first support 41 is located between adjacent crown beams 2 , and the second supports are located between adjacent retaining piles 1 .

[0047] In one embodiment, the support structure further includes a lattice column 51 and a longitudinal connecting beam 52, the longitudinal connecting beam 52 is fixedly arranged above the lattice column 51, the lattice column 51 supports the longitudinal connecting beam 52, the temporary cover 6 is covered on the connecting beam, and the second support is connected to the lattice column 51. The lattice column 51 and the longitudinal connecting beam 52 are located at the center line of the road.

[0048] A construction method for a temporary cover plate support structure for an open excavation foundation pit, applicable to the above-mentioned temporary cover plate support structure for an open excavation foundation pit, comprises the following steps:

[0049] S1: Foundation construction: construct retaining piles. After the construction is completed, the pile heads will be chiseled off and the cap beam will be constructed;

[0050] S2: Treat the crown beam: reserve dowel bars on the crown beam, roughen the surface of the crown beam to form several grooves, clean the grooves and apply an interface treatment agent on the groove interface;

[0051] S3: Construction of supporting wall: connecting the reserved dowel bars with the transverse distribution steel bars, connecting the longitudinal force-bearing steel bars with the transverse distribution steel bars through the tie bars, supporting the formwork and pouring the concrete, and the concrete seeping into the groove;

[0052] S4: Construction of temporary cover: cast-in-place steel slow-setting soil and paving asphalt on top;

[0053] S4: Chiseling away the supporting structure: After the station construction is completed, the supporting walls and temporary cover plates are cut statically;

[0054] S5: Roadbed backfill: Restore the road surface structure according to the original road elevation.

[0055] In one embodiment, step S2: the depth of the grooves is not less than 40 mm, and the spacing between the grooves is not more than 150 mm.

[0056] For other contents of the temporary cover plate supporting structure for the open excavation foundation pit described in the present invention, please refer to the prior art and will not be described in detail here.

[0057] The above are only preferred embodiments of the present invention and are not intended to limit the present invention in any form. Therefore, any modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the technical solution of the present invention are still within the scope of the technical solution of the present invention.

[0058] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0059] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

Claims

1. A temporary cover support structure for an open excavation pit, characterized in that: include: retaining piles, cap beams and supporting walls; The crown beam is fixedly arranged above the retaining pile, the supporting wall is fixedly arranged above the crown beam, and a temporary cover plate is arranged on the supporting wall; The supporting wall comprises longitudinal stress-bearing steel bars, transverse distribution steel bars and tension bars, wherein the longitudinal stress-bearing steel bars and the transverse distribution steel bars are arranged vertically, and the longitudinal stress-bearing steel bars and the transverse distribution steel bars are connected by the tension bars; The cap beam includes a reserved dowel bar and a plurality of grooves, the reserved dowel bar is fixedly connected to the transversely distributed steel bars, and the supporting wall partly penetrates into the plurality of grooves; The longitudinal force-bearing steel bars, the transverse distribution steel bars and the reserved dowel bars are all glass fiber bars.

2. The temporary cover support structure for an open excavation pit according to claim 1, characterized in that: The longitudinal force-bearing steel bars include a first steel bar and a second steel bar, the first steel bar and the second steel bar are mutually anchored, one end of the first steel bar extends into the second steel bar by 1 / 3 of the length, and one end of the second steel bar extends into the first steel bar by 1 / 3 of the length.

3. The temporary cover support structure for an open excavation pit according to claim 1, characterized in that: The length of the transverse distributed steel bars anchored in the crown beam is not less than 1.5 times the tensile anchoring length and not less than 40 times the diameter of the longitudinal force-bearing steel bars.

4. The temporary cover support structure for an open excavation pit according to claim 1, characterized in that: The thickness of the supporting wall is 300mm-800mm.

5. The temporary cover support structure for an open excavation pit according to claim 1, characterized in that: It also includes a first support and a plurality of second supports, wherein the first support is located between adjacent crown beams, and the second support is located between adjacent retaining piles.

6. The temporary cover support structure for an open excavation pit according to claim 5, characterized in that: It also includes a lattice column and a longitudinal connecting beam, wherein the longitudinal connecting beam is fixedly arranged above the lattice column, the lattice column supports the longitudinal connecting beam, a temporary cover plate is arranged on the connecting beam, and the second support is connected to the lattice column.

7. The temporary cover support structure for an open excavation pit according to claim 6, characterized in that: The lattice columns and longitudinal connecting beams are located at the center line of the road.

8. A construction method for a temporary cover plate support structure for an open excavation foundation pit, applicable to the temporary cover plate support structure for an open excavation foundation pit according to any one of claims 1 to 7, characterized in that: The following steps are involved: S1: Foundation construction: construct retaining piles. After the construction is completed, the pile heads will be chiseled off and the cap beam will be constructed; S2: Processing the crown beam: reserve dowel bars on the crown beam, roughen the surface of the crown beam to form several grooves, clean the grooves and apply an interface treatment agent on the groove interface; S3: Construction of supporting wall: connecting the reserved dowel bars with the transverse distribution steel bars, connecting the longitudinal force-bearing steel bars with the transverse distribution steel bars through the tie bars, supporting the formwork and pouring the concrete, and the concrete seeping into the groove; S4: Construction of temporary cover: cast-in-place steel slow-setting soil and paving asphalt on top; S4: Chisel out the supporting structure: After the station construction is completed, statically cut the supporting walls and temporary cover.

9. The construction method of a temporary cover plate support structure for an open excavation foundation pit according to claim 8, characterized in that: In step S2: the depth of the grooves is not less than 40 mm, and the spacing between the grooves is not more than 150 mm.

Images