Structure treatment method for newly-built underground single body occupied by existing pipe jacking well

Abstract

The invention provides a structure treatment method for the position, occupied by an existing pipe jacking well, of a newly-built underground single body, and the method comprises the steps that existing pipe jacking well fender posts and a main body structure which occupy the main body structure of the newly-built underground single body are utilized, transformed and reinforced; the situation that a newly-built underground single body is occupied by the existing pipe-jacking well and consequently an enclosure structure is discontinuous can be well handled, and therefore the situation that excavation and supporting deformation of a newly-built foundation pit at the position of the existing pipe-jacking well is large and influences of the surrounding environment are large is avoided, the construction period of a project is greatly shortened, and the technical feasibility, the working efficiency and the implementation effect are greatly better than those of a traditional mode.

Description

Technical Field

[0001] The invention relates to the technical field of building foundation pit construction, and in particular to a method for structural treatment of a newly built underground monomer at a location occupied by an existing jacking pipe shaft. Background Art

[0002] At present, due to the rapid development of underground engineering, in the process of construction of retaining structures and main structures under complex environmental conditions, underground obstacles such as existing pipe wells are often encountered, making it increasingly common for retaining structures to be unable to close and for the main structure area to be occupied. In this regard, measures must be taken to deal with the obstacles. Traditional treatment methods include the following two methods:

[0003] 1) Adopt the obstacle removal method, that is, use the full-rotation drilling rig and other equipment to remove the existing pipe-jacking well structure, and then backfill it after it is completed. The backfilled earthwork needs to be excavated during the main structure construction stage, resulting in secondary economic waste;

[0004] 2) Adopt the method of bypassing obstacles, that is, relocate the newly built foundation pit retaining piles, and use the method of surrounding obstacles with the newly built retaining piles to ensure the integrity of the retaining structure. This method leads to an increase in the amount of retaining structure engineering, which not only prolongs the construction period and expands the scope of impact on the surrounding environment, but also causes secondary obstacles to the main structure construction.

[0005] In view of the shortcomings of traditional obstacle handling methods in the prior art, such as clearing or avoiding obstacles, which bring about limited construction period, secondary waste of engineering costs, and a large impact on the surrounding environment, technical personnel in this field have been looking for solutions. Summary of the invention

[0006] The purpose of the present invention is to provide a structural treatment method for a newly built underground unit occupied by an existing jacking pipe shaft, so as to solve the problems of limited construction period, secondary waste of engineering cost and wide impact on the surrounding environment when using traditional obstacle treatment methods in the prior art to clear or avoid them.

[0007] In order to solve the above technical problems, the present invention provides a method for treating the structure of a newly built underground unit occupied by an existing top pipe well, and the method for treating the structure of a newly built underground unit occupied by an existing top pipe well comprises the following steps:

[0008] S1: After the new underground single-body retaining structure is completed, high-pressure jet grouting piles are constructed at the joint between the existing jacking well and the new underground single-body retaining structure;

[0009] S2: Use high-pressure jet grouting piles to reinforce the existing underground surrounding pipelines within the influence range of the existing pipe jacking well;

[0010] S3: Lower the groundwater level to 0.5m below the excavation surface of the new foundation pit;

[0011] S4: chiseling away the existing pipe jacking well retaining piles to a first predetermined depth, and constructing a reinforced concrete ring beam on the top of the chiseled surface of the existing pipe jacking well retaining piles;

[0012] S5: Excavate the new foundation pit to the designed elevation of the pit bottom, and carry out the following constructions simultaneously during the excavation process:

[0013] The existing main structure of the top pipe well lining enclosure structure is chiseled out in the part of the newly built underground single main structure, and lime soil is backfilled in layers between the chiseled surface and the bottom of the pit and compacted tightly;

[0014] Excavate the backfill soil in the existing jacking pipe shaft to the bottom elevation of the new foundation pit and form a 1:1.5 slope. Reserve a second predetermined depth between the top of the slope and the bottom of the reinforced concrete ring beam as the inclined support operation space to construct slope protection;

[0015] S6: At the connection between the side wall of the new underground single structure and the bottom plate in the existing jacking shaft area, a reinforced concrete corbel integrated with the bottom plate is cast;

[0016] S7: Install an oblique brace between the reinforced concrete ring beam and the reinforced concrete corbel in the existing jacking shaft area;

[0017] S8: Continue to construct the upper structure of the newly built underground unit. After the upper structure reaches the design strength and specification requirements, remove the diagonal braces and reinforced concrete corbels, and backfill the soil to the designed ground elevation.

[0018] Optionally, in the structural treatment method for the location where the newly built underground unit is occupied by the existing jacking pipe shaft, in S1, the horizontal reinforcement range of the high-pressure rotary jet piles is a range greater than or equal to 1.7m close to the outside of the existing jacking pipe shaft water-stop curtain; the vertical reinforcement range is a range greater than or equal to 4m below the bottom of the newly built foundation pit.

[0019] Optionally, in the structural treatment method for the location where the newly built underground unit is occupied by the existing jacking pipe shaft, in S2, the operating depth of the high-pressure rotary jet pile is: 1.2m below the ground to the bottom of the existing jacking pipe shaft.

[0020] Optionally, in the structural treatment method for the location where the newly built underground unit is occupied by the existing jacking pipe shaft, in S2, the horizontal protection distance of the existing surrounding underground pipelines is greater than or equal to 500 mm, and the vertical protection distance is greater than or equal to 300 mm.

[0021] Optionally, in the method for structural treatment of the location where the newly built underground unit is occupied by the existing jacking pipe shaft, in S4, the first predetermined depth range is: 1460m~1660m.

[0022] Optionally, in the method for treating the structure of the newly built underground unit occupied by the existing pipe jacking shaft, S4 includes the following sub-steps:

[0023] S41: in the process of chiseling away the existing pipe jacking well retaining piles to the first predetermined depth, retaining the main reinforcement of the existing pipe jacking well retaining piles;

[0024] S42: Tie steel bars to the main reinforcement at the top of the chiseled surface of the existing jacking pipe shaft retaining piles, erect formwork and cast to form a reinforced concrete ring beam.

[0025] Optionally, in the structural treatment method for the location where the existing jacking pipe shaft is occupied by the newly built underground unit, in S42: the main reinforcement of the existing jacking pipe shaft retaining piles is anchored 40d inside the reinforced concrete ring beam; wherein d is the diameter of the main reinforcement.

[0026] Optionally, in the structural treatment method for the location where the newly built underground unit is occupied by the existing jacking pipe well, in S5, the process of constructing the slope protection includes the following steps:

[0027] Lay 8@200×200 steel mesh on the slope;

[0028] Spray C20 on the steel mesh surface to form a 100mm thick concrete surface layer;

[0029] The distance from the slope foot to the drainage ditch is greater than or equal to 1m.

[0030] Optionally, in the method for structural treatment of the location where the newly built underground unit is occupied by the existing jacking pipe shaft, in S5, the second predetermined depth range is: 850mm ~ 925mm.

[0031] Optionally, in the structural treatment method for the location where the newly built underground unit is occupied by the existing jacking pipe shaft, in S5, lime soil is backfilled in layers at an elevation of 1.0 m from the chiseled surface to the bottom of the pit and compacted tightly.

[0032] Optionally, in the structural treatment method for the location where the newly built underground unit is occupied by the existing jacking pipe shaft, in S7, the diagonal brace is HW400×400×13×21 steel.

[0033] In the structural treatment method for the location where the newly built underground unit is occupied by the existing jacking pipe shaft provided by the present invention, by utilizing, transforming and reinforcing the existing jacking pipe shaft retaining piles and main structure occupying the main structure of the newly built underground unit, the situation where the newly built underground unit is occupied by the existing jacking pipe shaft and the retaining structure is discontinuous can be well handled, thereby avoiding large deformation of the new foundation pit excavation support at the existing jacking pipe shaft and large impact on the surrounding environment, greatly shortening the construction period of the project, and being much better than traditional methods in terms of technical feasibility, work efficiency and implementation effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] The above and other objects, features and advantages of the present disclosure will become more apparent through a more detailed description of exemplary embodiments of the present disclosure in conjunction with the accompanying drawings, wherein like reference numerals generally represent like components throughout the exemplary embodiments of the present disclosure.

[0035] Figure 1 It is a flow chart of a method for structural treatment of a newly built underground unit occupied by an existing pipe jacking shaft in one embodiment of the present invention;

[0036] Figure 2 It is a schematic diagram of the structure after the new underground unit is treated by the structural treatment method of the existing top pipe shaft;

[0037] Figure 3 It is another schematic diagram of the structure after the new underground unit is treated by the structural treatment method at the location occupied by the existing jacking pipe shaft.

[0038] In the figure:

[0039] 1-high-pressure jet grouting pile; 2-horizontal reinforcement range; 3-vertical reinforcement range; 4-existing surrounding pipelines; 5-horizontal protection distance; 6'-vertical protection distance; 6-existing top pipe well; 7-new single unit; 8-existing top pipe well retaining pile; 9-first predetermined depth; 10-reinforced concrete ring beam; 11-oblique brace; 12-embedded steel plate; 13-existing top pipe well lining main structure; 14-distance from the chiseled surface to the bottom of the pit; 15-existing top Backfill soil in the pipe shaft; 16- inclined support working space; 17- concrete surface layer; 18- reinforced mesh surface; 19- distance from slope foot to drainage ditch; 20- reinforced concrete corbel; 21- existing top pipe shaft water-stop curtain; 22- corbel height; 23- new underground single structure side wall; 24- bottom plate; 25- removed part; 26- corbel width; 27- outer side of reinforced concrete corbel; 28- inner side of reinforced concrete corbel; 29- horizontal spacing of corbels. DETAILED DESCRIPTION

[0040] The structural treatment method for the location of the newly built underground unit occupied by the existing top pipe shaft proposed by the present invention is further described in detail below in combination with the accompanying drawings and specific embodiments. The advantages and features of the present invention will become clearer according to the following description and claims. It should be noted that the accompanying drawings are all in a very simplified form and are not in precise proportions, and are only used to conveniently and clearly assist in explaining the purpose of the embodiments of the present invention.

[0041] The present invention will now be described in further detail with reference to the accompanying drawings. These drawings are simplified schematic diagrams, which only illustrate the basic structure of the present invention in a schematic manner, and therefore only show the components related to the present invention.

[0042] In the description of the invention, it is necessary to understand that the terms “center”, “longitudinal”, “lateral”, “length”, “width”, “thickness”, “up”, “down”, “front”, “back”, “left”, “right”, “vertical”, “horizontal”, “top”, “bottom”, “inside”, “outside”, “clockwise”, “counterclockwise”, etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply 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 invention.

[0043] 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, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0044] In the 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 it can be an indirect connection through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in the invention can be understood according to the specific circumstances.

[0045] Please refer to Figures 1 to 3 The structural treatment method of the newly built underground monomer occupied by the existing top pipe well of the present invention comprises the following steps:

[0046] First, execute step S1. After the new underground single body retaining structure has been completed, construct a high-pressure rotary jet pile 1 at the lap joint of the existing jacking pipe shaft 6 and the new underground single body retaining structure; wherein, the horizontal reinforcement range 2 of the high-pressure rotary jet pile 1 is a range greater than or equal to 1.7m close to the outside of the existing jacking pipe shaft water-stop curtain (double-axis mixing pile) 21; the vertical reinforcement range 3 is a range greater than or equal to 4m below the bottom surface of the new foundation pit.

[0047] Next, please refer to Figure 2 , execute step S2, use high-pressure rotary jet piles 1 to reinforce the existing underground surrounding pipelines 4 within the influence range of the existing top pipe well 6; wherein, the high-pressure rotary jet piles 1 can be selected as 700@500mm, with a cement content of 20%; the operating depth of the high-pressure rotary jet piles 1 is: 1.2m below the ground to the bottom of the existing top pipe well 6; the horizontal protection distance 5 of the existing underground surrounding pipelines 4 is greater than or equal to 500mm, and the vertical protection distance 6' is greater than or equal to 300mm.

[0048] Next, step S3 is executed to lower the groundwater level to 0.5 m below the excavation surface of the new foundation pit.

[0049] Next, execute step S4 to transform the existing jacking pipe shaft 6: chisel out the existing jacking pipe shaft retaining piles 8 to a first predetermined depth 9, and construct a reinforced concrete ring beam 10 on the top of the chiseled surface of the existing jacking pipe shaft retaining piles 8; in this embodiment, the first predetermined depth 9 is preferably in the range of: 1460m to 1660m.

[0050] Specifically, S4 includes the following sub-steps:

[0051] S41: during the process of chiseling away the existing pipe jacking well retaining piles 8 to the first predetermined depth 9, the main reinforcement of the existing pipe jacking well retaining piles 8 is retained;

[0052] S42: Tie steel bars to the main bars on the top of the chiseled surface of the existing top pipe well retaining pile 8, erect formwork and cast to form a reinforced concrete ring beam 10. Specifically, the main bars of the existing top pipe well retaining pile 8 are anchored 40d inside the reinforced concrete ring beam 10, where d is the diameter of the main bars.

[0053] Next, step S5 is executed to excavate a new foundation pit to the designed elevation of the pit bottom, and the following construction is carried out simultaneously during the excavation process:

[0054] Remove the existing top pipe shaft 6 structure occupation area: the existing top pipe shaft lining main structure 13 enclosure structure occupied by the new underground monomer main structure is removed (corresponding to Figure 2 The chiseled portion 25 is backfilled with lime soil in layers between the chiseled surface and the pit bottom and compacted tightly; in this embodiment, the lime soil is backfilled in layers at an elevation position where the distance 14 between the chiseled surface and the pit bottom is 1.0m and compacted tightly.

[0055] The backfill soil 15 in the existing jacking pipe well 6 is excavated to the bottom elevation of the newly built foundation pit, and a 1:1.5 slope is formed. A second predetermined depth is reserved between the top of the slope and the bottom surface of the reinforced concrete ring beam 10 as an inclined support operation space 16 to construct slope protection; specifically, the second predetermined depth range is: 850mm~925mm; The process of constructing slope protection includes the following steps:

[0056] A 8@200×200 steel mesh surface 18 is laid on the slope surface; C20 is sprayed on the steel mesh surface 18 to form a 100mm thick concrete surface layer 17; the distance 19 from the slope foot to the drainage ditch is greater than or equal to 1m.

[0057] Next, step S6 is executed to cast a reinforced concrete corbel 20 integral with the bottom plate 24 at the connection between the newly built underground single structure side wall 23 and the bottom plate 24 in the existing top pipe shaft 6 area.

[0058] Next, step S7 is performed, reinforcement treatment: an inclined brace 11 is installed between the reinforced concrete ring beam 10 and the reinforced concrete corbel 20 in the existing jacking shaft 6 area; the inclined brace 11 is preferably HW400×400×13×21 steel.

[0059] Specifically, both ends of the diagonal brace 11 are connected to the reinforced concrete ring beam 10 and the reinforced concrete corbel 20 through embedded steel plates 12. The cross-section of the reinforced concrete ring beam 10 is 1200mm×800mm. The length, width and height of the embedded steel plate 12 partially embedded in the reinforced concrete ring beam 10 are 600mm×800mm×25mm. The center of the embedded steel plate 12 and the center of the cross-section of the reinforced concrete ring beam 10 are on the same axis.

[0060] The reinforced concrete corbel 20 is constructed as follows: additional main reinforcement is arranged on the upper part of the reinforced concrete corbel 20, the corbel height 22 is 800mm above the top plate surface, the corbel width 26 is equal to the width of the embedded steel plate 12, the outer side 27 of the reinforced concrete corbel adopts a 1:0.625 variable cross-section for transition, and the inner side 28 of the reinforced concrete corbel adopts a 1:1 variable cross-section for transition; the plane layout of the reinforced concrete corbel 20 is as follows: one reinforced concrete corbel 20 is arranged along the center line of the existing top pipe shaft 6, and the remaining reinforced concrete corbels 20 are symmetrically arranged on both sides of the center line, and the horizontal spacing 29 of adjacent corbels is 2.6m; additional main reinforcement is pre-arranged inside the reinforced concrete corbel 20, and the length of its anchoring into the bottom plate 24 is not less than the seismic anchoring length of the steel bar, and its support stirrup adopts a four-limb stirrup, and the stirrup range is 500mm outward of the corbel; and the embedded steel plate 12 is arranged on the outer slope surface of the reinforced concrete corbel 20 to ensure that the center of the embedded steel plate 12 and the reinforced concrete corbel 20 are on the same axis.

[0061] Next, step S8 is executed to continue construction of the upper structure of the newly built underground unit 7. After the upper structure reaches the design strength and specification requirements, the diagonal brace 11 and the reinforced concrete corbel 20 are removed, and the soil is backfilled to the designed ground elevation.

[0062] Please refer to Figure 2 and Figure 3 Based on the present invention, the treatment method of the present invention is used to treat the structure of the newly-built underground monomer at the location occupied by the existing jacking pipe shaft. Based on the use, transformation and reinforcement of the existing jacking pipe shaft retaining piles and main structure occupying the main structure of the newly-built underground monomer, the situation in which the newly-built underground monomer is occupied by the existing jacking pipe shaft and the retaining structure is discontinuous can be well handled, thereby avoiding large deformation of the new foundation pit excavation support at the existing jacking pipe shaft and large impact on the surrounding environment. Compared with the clearing or avoidance method, the construction period of the project is greatly shortened, and it is much better than the traditional method in terms of technical feasibility, work efficiency and implementation effect.

[0063] It should be noted that, for the aforementioned method embodiments, for the sake of simplicity, they are all expressed as a series of action combinations, but those skilled in the art should be aware that the present application is not limited by the described order of actions, because according to the present application, certain steps can be performed in other orders or simultaneously. Secondly, those skilled in the art should also be aware that the embodiments described in the specification are all preferred embodiments, and the actions and modules involved are not necessarily required by the present application.

[0064] The above description is only a description of the preferred embodiments of the present invention, and is not intended to limit the scope of the present invention. Any changes or modifications made by a person skilled in the art in the field of the present invention based on the above disclosure shall fall within the scope of protection of the claims.

Claims

1. A method for structural treatment of a newly built underground unit occupied by an existing pipe jacking well, characterized in that: The following steps are involved: S1: After the new underground single body enclosure structure has been completed, high pressure jet grouting piles (1) are constructed at the lap joint between the existing jacking pipe well (6) and the new underground single body enclosure structure; S2: Using high-pressure jet grouting piles (1) to reinforce the existing underground surrounding pipelines (4) within the influence range of the existing pipe jacking well (6); S3: Lower the groundwater level to 0.5m below the excavation surface of the new foundation pit; S4: chiseling away the existing pipe jacking well retaining pile (8) to a first predetermined depth (9), and constructing a reinforced concrete ring beam (10) on the top of the chiseled surface of the existing pipe jacking well retaining pile (8); S5: Excavate the new foundation pit to the designed elevation of the pit bottom, and carry out the following constructions simultaneously during the excavation process: The existing top pipe well lining main structure (13) enclosure structure is chiseled out in the part where the newly built underground single body main structure is located, and lime soil is backfilled in layers between the chiseled out surface and the pit bottom and compacted tightly; Excavating the backfill soil (15) in the existing jacking pipe well (6) to the bottom elevation of the newly built foundation pit and forming a 1:1.5 slope, reserving a second predetermined depth between the top of the slope and the bottom of the reinforced concrete ring beam (10) as an inclined support operation space (16) to construct slope protection; S6: Casting a reinforced concrete corbel (20) integral with the bottom plate (24) at the connection between the newly built underground single structure side wall (23) and the bottom plate (24) in the existing top pipe shaft (6); S7: installing an inclined brace (11) between a reinforced concrete ring beam (10) and a reinforced concrete corbel (20) in the existing jacking shaft (6); S8: Continue to construct the upper structure of the newly built underground unit (7). After the upper structure reaches the design strength and specification requirements, remove the diagonal brace (11) and reinforced concrete bracket (20), and backfill the soil to the designed ground elevation.

2. The method for structural treatment of a newly built underground unit occupied by an existing jacking pipe shaft as claimed in claim 1, characterized in that: In S1, the horizontal reinforcement range (2) of the high-pressure jet grouting pile (1) is a range greater than or equal to 1.7 m close to the outside of the existing pipe jacking well water-stop curtain (21); the vertical reinforcement range (3) is a range greater than or equal to 4 m below the bottom surface of the newly built foundation pit.

3. The method for structural treatment of a newly built underground unit occupied by an existing pipe jacking shaft as claimed in claim 1, characterized in that: In S2, the operating depth of the high-pressure jet grouting pile (1) is from 1.2 m below the ground to the bottom of the existing jacking well (6).

4. The method for structural treatment of a newly built underground unit occupied by an existing pipe jacking shaft as claimed in claim 1, characterized in that: In S2, the horizontal protection distance (5) of the existing underground surrounding pipelines (4) is greater than or equal to 500 mm, and the vertical protection distance (6') is greater than or equal to 300 mm.

5. The method for structural treatment of a newly built underground unit occupied by an existing pipe jacking shaft as claimed in claim 1, characterized in that: In S4, the first predetermined depth (9) ranges from 1460m to 1660m.

6. The method for structural treatment of a newly built underground unit occupied by an existing pipe jacking shaft as claimed in claim 1, characterized in that: S4 includes the following sub-steps: S41: in the process of chiseling away the existing pipe jacking well retaining pile (8) to the first predetermined depth (9), retaining the main reinforcement of the existing pipe jacking well retaining pile (8); S42: Tie steel bars to the main reinforcement at the top of the chiseled surface of the existing jacking well retaining pile (8), erect a formwork and cast to form a reinforced concrete ring beam (10).

7. The method for structural treatment of a newly built underground unit occupied by an existing pipe jacking shaft as claimed in claim 6, characterized in that: In S42: the main reinforcement of the existing jacking well retaining pile (8) is anchored into the interior of the reinforced concrete ring beam (10) by 40d; wherein d is the diameter of the main reinforcement.

8. The method for structural treatment of a newly built underground unit occupied by an existing pipe jacking shaft as claimed in claim 1, characterized in that: In S5, the process of constructing slope protection includes the following steps: Lay 8@200×200 steel mesh (18) on the slope; Spray C20 on the steel mesh surface (18) to form a 100 mm thick concrete surface layer (17); The distance from the slope foot to the drainage ditch (19) is greater than or equal to 1m.

9. The method for structural treatment of a newly built underground unit occupied by an existing jacking pipe shaft as claimed in claim 1, characterized in that: In S5, the second predetermined depth range is: 850 mm to 925 mm.

10. The method for structural treatment of a newly built underground unit occupied by an existing jacking pipe shaft as claimed in claim 1, characterized in that: In S5, lime soil is backfilled in layers at an elevation of 1.0 m from the chiseled surface to the pit bottom (14) and compacted tightly.

11. The method for structural treatment of a newly built underground unit occupied by an existing jacking pipe shaft as claimed in claim 1, characterized in that: In S7, the diagonal brace (11) is a HW400×400×13×21 steel.

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