Manhole filling reinforcement structure and construction method thereof

Abstract

The application discloses a manhole filling reinforcement structure and a construction method thereof, and belongs to the technical field of underground structures. The application solves the technical problem of the influence of large-area filling above an existing underground manhole on the structural safety and settlement of the manhole. The manhole filling reinforcement structure comprises a foundation structure and a cover structure. The foundation structure is located around the lower part of the existing underground manhole. The cover structure is a semi-closed structure, which is located above the foundation structure and covers the upper part of the existing underground manhole. The application further provides a construction method of the manhole filling reinforcement structure. Compared with the scheme of directly removing the existing underground manhole and newly building the manhole, the application can utilize the existing underground manhole and reinforce the surrounding structure and foundation of the existing underground manhole, thereby effectively saving engineering investment.

Description

Technical Field

[0001] This invention belongs to the field of underground structure technology, specifically relating to a manhole filling reinforcement structure and its construction method. Background Technology

[0002] With the continuous development of municipal transportation in my country, various new and reconstructed roads, bridges, tunnels and other projects are constantly emerging, resulting in many issues of mutual influence with existing underground structures. When roads or landscaping require raising the ground elevation, large-scale backfilling has a significant impact on underground structures, causing additional stress damage or settlement deformation and other catastrophic problems to existing structures.

[0003] With the expansion of urban areas and the increase in municipal needs, numerous important pipelines, such as gas pipes, water supply pipes, power and communication pipes, and stormwater and sewage pipes, have been laid underground. Replacing these pipelines and existing underground manholes due to backfilling would result in significant investment waste and forced closure of existing manholes during construction, severely impacting municipal operations and public welfare. Modifications to stormwater and sewage pipes may involve temporary inverted siphon drainage, causing substantial environmental pollution and impacting environmental protection. Currently, methods for reinforcing existing foundations to prevent settlement are limited, such as grouting and anchor piles (referencing the "Technical Specification for Reinforcement of Existing Building Foundations JGJ123-2012"). However, grouting has limited reinforcement scope, and anchor piles require extending the existing manhole base structure, resulting in a long construction period. These methods are not effective for existing underground manhole structures under large-area backfilling.

[0004] Therefore, how to adopt safe, economical and reliable construction methods to ensure that the impact of backfilling on existing underground manholes is within a controllable range, and to ensure that pipelines and existing underground manholes can operate normally and safely during and after backfilling construction, is an important issue that urgently needs to be addressed in the process of urban development. Summary of the Invention

[0005] In view of the shortcomings of the existing technology, the purpose of this invention is to provide a manhole filling reinforcement structure; another purpose of this invention is to provide a construction method for the manhole filling reinforcement structure, so as to realize large-area filling without replacing existing underground manholes and ensure the normal operation of the pipeline network during the construction process.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: a manhole filling reinforcement structure, comprising a foundation structure and a cover structure; the foundation structure is located around the existing underground manhole; the cover structure is a semi-enclosed structure, located above the foundation structure and covering the upper part of the existing underground manhole, the cover structure isolates the existing underground manhole from the outer fill soil located above the existing underground manhole and the existing soil located around the existing underground manhole.

[0007] Furthermore, the foundation structure is a completely isolated soil structure or a partially isolated soil structure, wherein the partially isolated soil structure adopts a spaced pile arrangement.

[0008] Furthermore, the foundation structure adopts a rigid isolation body or a flexible isolation body; the rigid isolation body is a bored cast-in-place pile or a diaphragm wall, and the flexible isolation body is a crushed stone pile or a cement-soil mixing pile.

[0009] Furthermore, the bottom of the foundation structure extends into the bearing layer beneath the existing underground inspection well foundation.

[0010] Furthermore, the foundation structure avoids the pipeline structure connected to the existing underground inspection well, and the soil between the pipeline structure and the foundation structure is reinforced by grouting.

[0011] Furthermore, the cover structure includes a top plate structure and a side wall structure; the volume enclosed by the top plate structure and the side wall structure is larger than the volume of the existing underground inspection well.

[0012] Furthermore, the cover structure includes a platform structure, which is horizontally arranged inside the cover structure. The platform structure is a plate-like structure and is connected to the existing underground inspection well cover.

[0013] Furthermore, the cover structure includes a manhole structure, which is a cylindrical structure used to connect the platform structure and the top surface of the outer backfill soil; steps are provided inside the manhole structure.

[0014] Furthermore, the cover structure includes a ring beam located at the connection between the side wall structure and the foundation structure, and the cross-sectional width of the ring beam is greater than the cross-sectional width of the side wall structure.

[0015] The construction method for the above-mentioned manhole backfill reinforcement structure includes the following steps:

[0016] (1) Construct the foundation structure around the existing underground inspection well;

[0017] (2) Construct a ring beam on top of the foundation structure;

[0018] (3) Cast the cover structure on the ring beam;

[0019] (4) Install equipment inside the covered structure;

[0020] (5) Cover the outer backfill soil.

[0021] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0022] (1) Compared with the solution of directly demolishing existing underground inspection wells and building new ones, the present invention provides a structural measure that can utilize existing underground inspection wells and reinforce the surrounding structure and foundation of existing underground inspection wells, which can effectively save engineering investment.

[0023] (2) This invention can be implemented without interrupting the normal operation of the pipeline. It plays an important role in reducing the impact on the surrounding municipal supply, reducing environmental pollution, and reducing the impact on the surrounding traffic. It is worth promoting on a large scale.

[0024] (3) Compared with existing foundation reinforcement methods, the present invention can effectively control the additional load generated by large-area filling, control settlement better, and will not damage the foundation of the existing structure, with less disturbance. Attached Figure Description

[0025] Figure 1 This is a plan view of the manhole backfill reinforcement structure of the present invention;

[0026] Figure 2 for Figure 1 AA cross-section view;

[0027] Figure 3 for Figure 1 BB cross-section;

[0028] Among them, 1. Existing underground inspection well; 12. Pipeline structure; 2x. Cover structure; 21. Top slab structure; 22. Manhole structure; 221. Steps; 23. Platform structure; 24. Side wall structure; 25. Ring beam; 3. Foundation structure; 4. Existing soil; 5. Outer backfill soil; 6. Grouting soil. Detailed Implementation

[0029] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0030] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. The terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance. Furthermore, unless otherwise explicitly specified and limited, the terms "installed," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0031] Please see Figure 1 and Figure 2 This illustration shows a preferred embodiment of the present invention, a manhole backfill reinforcement structure, including a foundation structure 3 and a cover structure 2x; the foundation structure 3 is located around the existing underground manhole 1; the cover structure 2x is a semi-enclosed structure, located above the foundation structure 3 and covering the upper part of the existing underground manhole 1, for isolating the existing underground manhole 1 from the outer backfill soil 5 located above the existing underground manhole 1 and the existing soil 4 located around the existing underground manhole 1.

[0032] For details, please see Figure 2 and Figure 3 The foundation structure 3 adopts a rigid isolation body, which is a bored pile. The foundation structure is either a completely isolated soil structure or a partially isolated soil structure. In this embodiment, the foundation structure 3 is a partially isolated soil structure. The partially isolated soil structure adopts a spaced pile arrangement. Bored piles are constructed at intervals in the existing soil 4. Due to the soil arching effect, the net distance between two adjacent bored piles is 200-500mm, which can ensure the soil isolation effect and prevent the horizontal soil pressure and uplift soil pressure below the existing underground manhole 1 foundation from affecting the existing underground manhole 1 after backfilling.

[0033] Foundation structure 3 uses a rigid isolator made of bored cast-in-place piles. Construction will not cause soil displacement, which can reduce the deformation impact on the existing underground inspection well 1. Foundation structure 3 can use either a rigid isolator or a flexible isolator; the rigid isolator is a bored cast-in-place pile or a diaphragm wall, and the flexible isolator is a crushed stone pile or a cement-soil mixing pile; extrusion piles such as PHC pipe piles are not recommended.

[0034] The depth to which the foundation structure 3 extends below the existing underground inspection well foundation is determined based on the bearing capacity of the superstructure load and the anti-uplift stability of the outer soil entering the inner space of the existing underground inspection well. Preferably, its depth extends into the bearing layer with better soil quality, such as sandy gravel soil layer, moderately weathered soil layer, etc.

[0035] The foundation structure 3 avoids the connection between the pipeline structure 12 and the existing underground inspection well 1, and the net distance between the adjacent bored piles and the pipeline structure 12 is not less than 200mm. The soil between the pipeline structure and the bored piles can be reinforced by grouting to form grouting soil 6. The grouting fluid can be cement grout or cement-water glass two-component grout, depending on the soil conditions.

[0036] The enclosure structure 2x includes a top slab structure 21 and side wall structures 24, used to isolate the existing soil 4 and the outer fill soil 5. The volume enclosed by the top slab structure 21 and side wall structures 24 is larger than the volume of the existing underground manhole 1. That is, the side wall structure 24 is located around the existing underground manhole 1, and the clearance between the side wall structure and the existing underground manhole is at least 500mm to reserve space for the formwork of the side wall concrete. The top slab structure 21 is located above the top slab of the existing underground manhole 1, and the clearance between the top slab structure and the top slab of the existing underground manhole is at least 2m to facilitate personnel maintenance and to be adjusted according to the height of the outer fill soil 5. The outer walls of the top slab structure 21 and the side wall structure 24 should preferably be coated with a cement-based penetrating crystalline material as a waterproof protective layer.

[0037] The cover structure 2x includes a platform structure 23, which is horizontally positioned inside the cover structure 2x. The platform structure 23 is a plate-like structure and is connected to the existing underground inspection well 1 top cover. The existing underground inspection well 1 top cover is located at the opening of the platform structure, and the size of the existing underground inspection well 1 top cover is consistent with the size of the opening of the platform structure.

[0038] The cover structure 2x includes a manhole structure 22, which is a cylindrical structure used to connect the platform structure 23 and the top surface of the outer backfill 5. Steps 221 are provided inside the manhole structure to lead from the top surface of the outer backfill 5 to the platform structure 23 for maintenance.

[0039] The canopy structure 2x includes a ring beam 25, which is located at the connection between the side wall structure 24 and the foundation structure 3 of the canopy structure 2x, that is, at the connection between the bottom of the side wall structure 24 and the top of the foundation structure 3. The cross-sectional width of the ring beam is greater than that of the side wall structure 24, and the ring beam has greater stiffness, which can effectively resist the additional load of lateral earth pressure backfill and ensure structural safety.

[0040] This embodiment also provides a construction method for the above-mentioned manhole backfill reinforcement structure, including the following steps:

[0041] (1) Construct foundation structure 3 around the existing underground inspection well 1; the gap between foundation structure 3 and the existing underground inspection well 1 is 500mm, and the frame for constructing bored piles is erected. The drilling is carried out using the positive circulation or reverse circulation mud wall protection construction process, the steel cage is placed, and underwater concrete is poured; the construction of bored piles should be carried out in a step-by-step manner to prevent the hole from collapsing.

[0042] (2) Construct ring beam 25 at the top of foundation structure 3; remove the floating slag concrete at the top of the bored pile to expose the steel bars for anchoring, erect the ring beam formwork, tie the steel cage, pour concrete, and carry out the next step of construction after the concrete reaches 70% of the design strength.

[0043] (3) Cast the cover structure 2x on the ring beam 25; set the concrete pouring sequence according to the structural form. You can first pour up to the platform structure 23, leave a construction joint, and then pour the top slab structure 21 and the manhole structure 22; the construction joint must be equipped with necessary waterproof measures, such as water-stop steel plate or water-stop strip.

[0044] (4) Install equipment inside the cover structure 2x; the equipment includes steps 211, hooks, and drainage pumps; steps 221 can be steel-plastic ladders or steel ladders; for existing underground inspection wells that need to be considered for hoisting valves, water pumps, etc., hooks can be installed inside the top plate structure 21; to prevent water accumulation inside the cover structure 2x, a drainage pump can be installed below the platform structure 23 and connected to the power supply system for operation during subsequent maintenance;

[0045] (5) Cover the outer fill soil; after the concrete strength of the cover structure 2x meets the design requirements of 70%, cover the outer fill soil 5. In this embodiment, it is located in the fill soil behind the bridge abutment. The soil above must meet the requirements of roadbed filling. The roadbed fill material meets a certain gradation and the compaction degree is not less than 0.93.

[0046] The manhole reinforcement structure in this embodiment solves the problem of the impact of large-area backfilling above existing underground manholes on their structural safety and settlement. It eliminates the need to demolish existing underground manholes, providing on-site reinforcement and protection without interrupting pipeline operation. During construction, it has minimal impact on existing underground manholes, is relatively inexpensive, and is highly feasible, making it worthy of widespread promotion.

[0047] 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 within the protection scope of the present invention.

Claims

1. A manhole backfill reinforcement structure, characterized in that, It includes a foundation structure and a cover structure; the foundation structure is located around the existing underground inspection well; the cover structure is a semi-enclosed structure, located above the foundation structure and covering the upper part of the existing underground inspection well; The foundation structure is a partially isolated soil structure, which adopts a spaced pile arrangement with a net spacing of 200-500mm. The foundation structure adopts a rigid isolation body or a flexible isolation body; the rigid isolation body is a bored cast-in-place pile or a diaphragm wall, and the flexible isolation body is a crushed stone pile or a cement-soil mixing pile; The bottom of the foundation structure extends into the bearing layer below the existing underground inspection well foundation; The enclosure structure includes a top slab structure and side wall structures; the volume enclosed by the top slab structure and side wall structures is larger than the volume of the existing underground inspection well. The cover structure includes a ring beam located at the connection between the side wall structure and the foundation structure, and the cross-sectional width of the ring beam is greater than the cross-sectional width of the side wall structure.

2. The manhole backfill reinforcement structure according to claim 1, characterized in that, The foundation structure avoids the pipeline structure connected to the existing underground inspection well, and the soil between the pipeline structure and the foundation structure is reinforced by grouting.

3. The manhole backfill reinforcement structure according to claim 2, characterized in that, The cover structure includes a platform structure, which is horizontally arranged inside the cover structure. The platform structure is a plate-shaped structure and is connected to the existing underground inspection well cover.

4. The manhole backfill reinforcement structure according to claim 3, characterized in that, The cover structure includes a manhole structure, which is a cylindrical structure used to connect the platform structure and the top surface of the outer backfill soil; steps are provided inside the manhole structure.

5. The construction method of the manhole backfill reinforcement structure according to any one of claims 1 to 4, characterized in that, Includes the following steps: (1) Construct the foundation structure around the existing underground inspection well; (2) Construct a ring beam on top of the foundation structure; (3) Cast the cover structure on the ring beam; (4) Install equipment inside the covered structure; (5) Cover the outer backfill soil.

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