Complex geology foundation pit wall repairing reverse construction system

Abstract

The utility model provides a complex geology foundation pit wall repairing reverse construction system, the complex geology foundation pit wall repairing reverse construction system comprises a reverse construction wall, a foundation pit support and a crown beam, the foundation pit support is arranged on the outer side of an underground structure and is a foundation pit supporting structure; the top beam is arranged above the foundation pit support; the reversed wall is located on the side wall of the foundation pit and connected with the foundation pit support and the top beam, the reversed wall comprises reversed wall vertical ribs and reversed wall transverse ribs, the reversed wall vertical ribs and the reversed wall transverse ribs are vertically and transversely arranged in an interactive mode to form a reinforcing mesh, the reversed wall vertical ribs are connected with top beam embedded ribs of the top beam, and the reversed wall transverse ribs are connected with the foundation pit support; and grouting holes and grout overflow holes are formed in the reverse wall, so that unfavorable geology with looseness and / or cavities on the initially formed reverse wall can be subjected to grouting reinforcement. The device has the advantages that sand and water gushing of the foundation pit is prevented, and the safety of the foundation pit is ensured.

Description

Technical Field

[0001] The utility model relates to the technical field of tunnels and underground engineering, and in particular to a reverse construction system for filling walls in complex geological foundation pits. Background Art

[0002] During the construction of subway stations, underground pipelines are not only numerous and complex, but also difficult to relocate, seriously affecting the construction of the station foundation pit retaining structure. Relocation to the outside of the subway station foundation pit or underground continuous wall splicing construction technology or ground grouting to reinforce the soil is often adopted. Currently, due to the large space occupied by pipelines, unknown burial depth and location, and complex geological conditions of the foundation pit (sand layers, silty soil), the foundation pit cannot be sealed, and the splicing construction technology and ground grouting to reinforce the soil are not suitable, posing a high safety risk. Therefore, it is of great significance to provide a reverse construction system for complex geological foundation pits. Utility Model Content

[0003] In view of the shortcomings of the prior art, the present invention aims to solve one or more problems in the prior art. For example, one of the purposes of the present invention is to provide a reverse construction system for foundation pits in complex geological conditions to prevent sand and water gushing out of the foundation pit.

[0004] In order to achieve the above-mentioned purpose, the present invention provides, on the one hand, a reverse construction system for complex geological foundation pit wall filling, which may include a reverse construction wall, a foundation pit enclosure and a crown beam, wherein the foundation pit enclosure is arranged on the outside of the underground structure and is a foundation pit support structure; the crown beam is arranged above the foundation pit enclosure; the reverse construction wall is located on the side wall of the foundation pit and is connected to the foundation pit enclosure and the crown beam, and the reverse construction wall includes vertical reinforcement of the reverse construction wall and transverse reinforcement of the reverse construction wall, and the vertical reinforcement of the reverse construction wall and the transverse reinforcement of the reverse construction wall are respectively arranged vertically and transversely to form a steel mesh, the vertical reinforcement of the reverse construction wall is connected to the crown beam embedded reinforcement of the crown beam, and the transverse reinforcement of the reverse construction wall is connected to the foundation pit enclosure; grouting holes and overflow holes are provided on the reverse construction wall to perform grouting reinforcement on the poor geological conditions of the initially formed reverse construction wall that are loose and / or hollow.

[0005] According to an exemplary embodiment of one aspect of the present invention, the length of the crown beam embedded reinforcement inserted into the soil may be more than 200 mm.

[0006] According to an exemplary embodiment of one aspect of the present invention, the vertical reinforcement of the reverse wall is welded to the embedded reinforcement of the crown beam, and the transverse reinforcement of the reverse wall is welded to the foundation pit enclosure. The welding can be single-sided welding 5d or double-sided welding 10d.

[0007] According to an exemplary embodiment of one aspect of the present invention, the top-down wall may include a reinforced concrete wall with a thickness of 40 to 60 cm, and the concrete may be of grade C35P8.

[0008] According to an exemplary embodiment of one aspect of the present invention, the steel mesh may be an HRB400 grade steel mesh.

[0009] According to an exemplary embodiment of one aspect of the present invention, the top-down wall may include a reinforced concrete wall formed by grouting.

[0010] According to an exemplary embodiment of one aspect of the present invention, the grouting slurry may include cement-water-glass double-liquid slurry.

[0011] According to an exemplary embodiment of one aspect of the present invention, a grouting pipe may be provided in the grouting hole; a small grouting conduit may be provided on the reverse wall, and the small grouting conduit is inclined, and its angle with the horizontal plane is less than 45°.

[0012] According to an exemplary embodiment of one aspect of the present invention, the small grouting conduit may include a steel flower pipe with a diameter of 28 to 36 mm and a length of 2 to 4 m.

[0013] According to an exemplary embodiment of one aspect of the present invention, a grouting hose may be connected to one end of the grouting pipe facing the foundation pit.

[0014] Compared with the prior art, the beneficial effects of the present invention include at least one of the following:

[0015] (1) In the case of a closed subway foundation pit affected by a major pipeline that cannot be relocated, the utility model proposes a reverse construction system for complex geological foundation pit wall filling to ensure the safety of the foundation pit.

[0016] (2) The utility model proposes a complex geological foundation pit wall filling reverse construction system that can be formed by a foundation pit sealing construction method, which can prevent sand and water from gushing out of the foundation pit. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The above and other objects and features of the present invention will become more apparent from the following description in conjunction with the accompanying drawings, in which:

[0018] Figure 1 Shows a schematic diagram of the unsealed structure of the foundation pit;

[0019] Figure 2 A schematic diagram of the location of the reverse wall is shown;

[0020] Figure 3 A partial structural diagram of a reverse wall is shown;

[0021] Figure 4 The schematic diagram of the structure of the complex geological foundation pit wall repair and top-down construction system of the present invention is shown;

[0022] Figure 5 It shows the schematic diagram of back grouting of the top-down system for foundation pit wall filling in complex geological conditions;

[0023] Figure 6 A schematic diagram of the side elevation of the grouting reinforcement part of the small grouting conduit is shown;

[0024] Figure 7 A schematic diagram of the front elevation of the grouting reinforcement part of the grouting small duct is shown.

[0025] Description of main reference numerals:

[0026] 1-crown beam, 2-embedded crown beam reinforcement, 3-foundation pit enclosure, 4-foundation pit, 5-reverse wall, 6-vertical reinforcement of reverse wall, 7-transverse reinforcement of reverse wall, 8-overflow hole, 9-grouting hole, 10-small grouting conduit, 11-grouting pipe, 12-grouting hose. DETAILED DESCRIPTION

[0027] Hereinafter, a complex geological foundation pit wall-filling reverse construction system of the present invention will be described in detail with reference to the accompanying drawings and exemplary embodiments.

[0028] In the description of the present application, it should be understood that the terms "middle", "upper", "lower", "rear", "horizontal", "bottom", "inside", "outside" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application. In the description of the present application, it should be noted that, unless otherwise clearly specified and limited, the term "connection" 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 direct connection, or an indirect connection through an intermediate medium, or it can be a communication between the internal parts of two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present utility model can be understood according to specific circumstances.

[0029] Exemplary embodiment 1

[0030] This exemplary embodiment provides a reverse construction system for complex geological foundation pit wall filling.

[0031] Figure 1 Shows a schematic diagram of the unsealed structure of the foundation pit; Figure 2 A schematic diagram of the location of the reverse wall is shown; Figure 3 A partial structural diagram of a reverse wall is shown; Figure 4 The schematic diagram of the structure of the complex geological foundation pit wall repair and top-down construction system of the present invention is shown; Figure 5 It shows the schematic diagram of back grouting of the top-down system for foundation pit wall filling in complex geological conditions; Figure 6 A schematic diagram of the side elevation of the grouting reinforcement part of the small grouting conduit is shown; Figure 7The schematic diagram of the front elevation of the grouting reinforcement part of the grouting small pipe is shown below. Figures 1 to 7 To describe the complex geological foundation pit wall repair reverse construction system of this exemplary embodiment. It should be noted that, Figure 6 and Figure 7 The unit of distance expressed is mm.

[0032] like Figure 1 As shown in , in the case where a major pipeline that cannot be relocated affects the closure of the foundation pit 4 (the existing pipeline affects the foundation pit and cannot be closed, and the pipeline affects the unconstructed foundation pit retaining structure), the utility model provides a complex geological foundation pit wall filling reverse construction system, which is formed through a safe foundation pit closure construction method to ensure the safety of the foundation pit.

[0033] like Figure 4 As shown in FIG, the complex geological foundation pit wall top-down construction system of this exemplary embodiment may include a top-down construction wall 5, a foundation pit enclosure 3 and a cap beam 1.

[0034] Among them, the foundation pit enclosure 3 is set outside the underground structure and is a foundation pit support structure; the crown beam 1 is set above the foundation pit enclosure 3. The reverse wall 5 is located on the side wall of the foundation pit and is connected to the foundation pit enclosure 3 and the crown beam 1. Figure 2 As shown in , the installation range of the reverse wall 5 can be located on the constructed foundation pit retaining structure 3. The reverse wall can include reverse wall vertical reinforcement and reverse wall transverse reinforcement. Figure 3 As shown in the figure, the vertical reinforcement 6 and the transverse reinforcement 7 of the reverse wall are arranged alternately vertically and horizontally to form a steel mesh, forming a force-bearing system. The vertical reinforcement 6 of the reverse wall is connected to the crown beam embedded reinforcement 2 of the crown beam 1, and the transverse reinforcement 7 of the reverse wall is connected to the foundation pit enclosure 3. Figure 4 As shown in the figure, overflow holes 8 and grouting holes 9 are provided on the reverse wall 5. Grouting holes can be used to reinforce the initially formed reverse wall with loose and / or hollow unfavorable geological conditions. Continuous and uniform grouting from the overflow holes can be used to determine that grouting should be stopped.

[0035] In this exemplary embodiment, the grouting holes are set in the modules corresponding to the adverse geological sections such as sand layer, silt, etc. The grouting holes can be located below or above the overflow hole.

[0036] In this exemplary embodiment, Figure 5 As shown in , a grouting pipe 11 is provided in the grouting hole, and a grouting hose 12 can be connected to one end of the grouting pipe 11 facing the foundation pit. The grouting hose is configured to transport slurry. The grouting pipe can be a steel pipe, and a grouting valve can be provided on the outside of the steel pipe.

[0037] In this exemplary embodiment, Figures 5 to 7 As shown in , a small grouting conduit 10 can be provided on the reverse wall, and the angle at which it is provided is less than 45°, which is the angle with the horizontal plane.

[0038] Furthermore, the grouting small conduit may include a steel pipe with a diameter of 28 to 36 mm, for example, 32 mm. Its length may be 2 to 4 m, for example, 3.5 m. Figures 6 and 7 As shown in , the vertical spacing between the pipes of the grouting small conduit can be 1000mm, and the horizontal spacing can be 300mm.

[0039] In this exemplary embodiment, the steel mesh may include HRB400 grade steel mesh.

[0040] In this exemplary embodiment, the vertical reinforcement of the reverse wall may be 20 mm diameter steel bars, which are vertically spaced 200 mm apart from each other, and the transverse reinforcement of the reverse wall may be 25 mm diameter steel bars, which are transversely spaced 200 mm apart from each other.

[0041] In this exemplary embodiment, the vertical reinforcement of the top-down wall is welded to the embedded reinforcement of the crown beam, with a single or double-sided weld length of 5d or 10d. The transverse reinforcement of the top-down wall is welded to the foundation pit enclosure, with a single or double-sided weld length of 5d or 10d. Here, 5d or 10d means the weld length is 10 times or 5 times the diameter of the bar, respectively, where d represents the bar diameter.

[0042] In this exemplary embodiment, the top-down wall may be a reinforced concrete wall formed by grouting, and the grouting slurry may include cement-water-glass double-liquid slurry.

[0043] Furthermore, the top-down wall may comprise a reinforced concrete wall with a thickness of 40 to 60 cm, for example 50 cm. The concrete of the top-down wall may be of grade C35P8.

[0044] In this exemplary embodiment, the length of the crown beam embedded reinforcement inserted into the soil can be more than 200 mm, which is convenient for welding the next section of steel mesh. The transverse spacing of the crown beam embedded reinforcement can be 200 mm.

[0045] The main construction idea of ​​the complex geological foundation pit wall filling reverse construction system of the present invention can be as follows: in a complex geological environment, the side walls of the foundation pit in the area affected by major pipelines are filled with reverse construction. Before filling the wall of each construction section, a small grouting tube (32mm diameter, 3.5m long steel flower pipe) is used to grout the lower soil part of the reverse construction wall at an oblique angle (less than 45°) to reinforce the poor geology. After the reinforcement is completed, the reverse construction wall is constructed. At this time, the bottom of the wall is grouting reinforced, the geology of the crown beam bottom is better, and there is no risk of collapse during the excavation process. After the construction of the reverse construction wall is completed, the loose and hollow areas behind the wall are grouting and filling by means of reverse construction wall opening grouting, and the grouting pressure shall not be greater than 0.3MPa. The above grouting can all use cement-water glass double liquid slurry.

[0046] Specifically, the construction process of the complex geological foundation pit wall filling top-down system of the present invention may include:

[0047] S1. Set up the crown beam of the construction pit retaining structure and embed the connecting steel bars of the top-down wall.

[0048] S2. Construct a top-down wall. The top-down wall shall be a 50cm thick reinforced concrete wall made of C35P8 grade concrete. A 22HRB400 grade steel mesh with a spacing of 200mm x 200mm shall be installed inside the top-down wall (the vertical and transverse bars of the top-down wall shall be constructed alternately). The steel bars shall be reliably welded, with a single-sided welding period of 5d or a double-sided welding period of 10d. The connection to the existing foundation pit retaining structure (piles or walls) shall be made by planting steel bars or by stripping the protective layer of the steel bars and welding them to the existing steel bars. Existing steel bars may refer to the pre-buried steel bars of the top-down wall that have already been constructed. Arc welding may be used for welding.

[0049] S3, reverse wall construction at the location of sand layer or silty soil layer, first grouting reinforcement of the lower soil at the bottom of the wall, and grouting reinforcement in the poor geological section. In this mode, there is no need for overflow holes and grouting holes. The grouting small pipe is a 32mm diameter steel pipe, about 3.5m long, and the construction angle is less than 45°. Here, the grouting parameters are: cement-water-glass double liquid slurry, the grouting pressure is about 0.3MPa, and the grouting is stopped when the slurry continues to overflow. The setting of the grouting small pipe can be as follows Figure 6 and Figure 7 As shown in , the vertical spacing between the grouting pipes can be 1000mm, and the horizontal spacing can be 300mm. The purpose of grouting at the bottom of the wall is to reinforce the next section of excavated soil to ensure the stability of the excavation surface and thus ensure safety.

[0050] S4. Strengthen the loose and poor geological conditions behind the wall with voids. For example, if there is a collapse during construction, a grouting hole is set behind the location where the void appears, and an overflow hole is set above the grouting hole. The overflow hole is set on the wall where no void appears. That is, grouting holes and overflow holes can be set on the constructed reverse wall, and cement-water-glass double liquid slurry can be injected. The grouting pressure is controlled within 0.3MPa, and the grouting is stopped after the overflow hole continuously and evenly discharges slurry. The purpose of grouting behind the wall is to fill and compact the void area behind the wall to prevent the upper soil from collapsing during the next excavation. When grouting the back of the wall, the setting of the grouting small pipe can be as follows: Figure 5 As shown in .

[0051] S5. After the grouting slurry solidifies to a certain strength (usually after 24 hours), the next section of the reverse wall is excavated and constructed. Repeat the above steps until all the foundation pit reverse walling is completed, forming a complex geological foundation pit reverse walling system. After the reverse construction is completed, the "foundation pit" structural feature can be a complete foundation pit retaining structure. Here, the construction space sequence is from top to bottom. After one section is completed, the next section is excavated. The segment length can usually be 1m.

[0052] In summary, the beneficial effects include:

[0053] The present invention provides a reverse construction system for filling walls in complex geological foundation pits, which is mainly used in the field of tunnels and underground engineering. The purpose of the present invention is to provide a way to safely close the foundation pit when a major pipeline that cannot be relocated affects the closure of a subway foundation pit. The reverse construction system for filling walls in complex geological foundation pits of the present invention can ensure the safety of the foundation pit, overcome the problems of large space occupied by ground pipelines, unknown buried depth and location, and complex geological conditions of the foundation pit (sand layer, silty soil), etc., adopts the complex geological reverse construction method for filling walls construction technology, performs grouting reinforcement behind and below the reverse wall, stabilizes the soil, and prevents sand and water gushing from the foundation pit during the excavation of the reverse wall, thereby ensuring the safety of the foundation pit.

[0054] Although a complex geological foundation pit wall filling reverse construction system of the present invention has been described above in combination with exemplary embodiments, it should be clear to those skilled in the art that various modifications and changes may be made to the exemplary embodiments of the present invention without departing from the spirit and scope defined by the claims.

Claims

1. A top-down construction system for complex geological foundation pit wall filling, characterized by: The complex geological foundation pit wall top-down construction system includes top-down walls, foundation pit enclosures and crown beams, wherein: The foundation pit enclosure is set outside the underground structure and serves as the foundation pit support structure; the crown beam is set above the foundation pit enclosure; The top-down wall is located on the side wall of the foundation pit and is connected to the foundation pit enclosure and the crown beam. The top-down wall includes vertical reinforcement and transverse reinforcement. The vertical reinforcement and transverse reinforcement are arranged alternately vertically and transversely to form a steel mesh. The vertical reinforcement of the top-down wall is connected to the embedded reinforcement of the crown beam, and the transverse reinforcement of the top-down wall is connected to the foundation pit enclosure. Grouting holes and overflow holes are provided on the top-down wall to perform grouting reinforcement on the unfavorable geological conditions of looseness and / or voids in the initially formed top-down wall.

2. The complex geological foundation pit wall repair top-down construction system according to claim 1 is characterized in that: The length of the crown beam embedded reinforcement inserted into the soil is more than 200 mm.

3. The complex geological foundation pit wall repair top-down construction system according to claim 1 is characterized in that: The vertical reinforcement of the reverse wall is welded to the embedded reinforcement of the crown beam, and the transverse reinforcement of the reverse wall is welded to the foundation pit enclosure. The welding is single-sided welding for 5d or double-sided welding for 10d.

4. The complex geological foundation pit wall repair top-down construction system according to claim 1 is characterized in that: The top-down wall comprises a reinforced concrete wall with a thickness of 40 to 60 cm, and the concrete is of grade C35P8.

5. The complex geological foundation pit wall repair top-down construction system according to claim 1 is characterized in that: The steel mesh is HRB400 grade steel mesh.

6. The complex geological foundation pit wall repair top-down construction system according to claim 1 is characterized in that: The top-down wall comprises a reinforced concrete wall formed by grouting.

7. The complex geological foundation pit wall repair top-down construction system according to claim 6 is characterized in that: The grouting slurry includes cement-water-glass double-liquid slurry.

8. The complex geological foundation pit wall repair top-down construction system according to claim 1 is characterized in that: A grouting pipe is provided in the grouting hole; a small grouting conduit is provided on the reverse wall, and the small grouting conduit is inclined, and the angle between the small grouting conduit and the horizontal plane is less than 45 degrees.

9. The top-down construction system for complex geological foundation pit wall repair according to claim 8 is characterized in that: The small grouting conduit comprises a steel flower pipe with a diameter of 28 to 36 mm and a length of 2 to 4 m.

10. The top-down construction system for complex geological foundation pit wall repair according to claim 8 is characterized in that: One end of the grouting pipe facing the foundation pit is connected with a grouting hose.

Images