Structure of rigid pile foundation of construction in limited space reinforced by composite foundation
By using a composite foundation reinforcement structure beneath existing structures, and employing high-pressure jet grouting piles and cement grout to form a continuous reinforced body, the problem of tunnel reinforcement with limited construction space was solved, achieving efficient foundation reinforcement and improved stability.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- GUANGZHOU MUNICIPAL ENG MASCH CO
- Filing Date
- 2025-06-20
- Publication Date
- 2026-06-02
AI Technical Summary
When constructing a new tunnel beneath an existing superstructure, the limited construction space and the inability of traditional methods to effectively reinforce the area between the side piles and the central piles make tunnel construction impossible.
A composite foundation reinforcement structure is adopted, which uses high-pressure jet grouting piles to form a rectangular space in a limited space. Combined with the existing rigid pile foundation and the newly built foundation piles, a continuous reinforced body is formed by high-pressure jet grouting piles and cement grout and high-pressure air dual-pipe grouting, which enhances the bearing capacity and impermeability of the foundation.
The reinforcement of weak foundations within a limited space was achieved, improving the bearing capacity and seismic performance of the foundation, ensuring safe and reliable construction, reducing groundwater infiltration and stress concentration, and enhancing the overall stability and impermeability of the foundation.
Smart Images
Figure CN224314255U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of building construction technology, specifically to a structure that uses composite foundation reinforcement for rigid pile foundations of structures within a limited space. Background Technology
[0002] In the field of building construction technology, after years of construction experience and exploration, both domestically and internationally, foundation treatment is often carried out through methods such as replacement, compaction, and composite foundations. These methods include replacing the subgrade, dynamic compaction, sand and gravel piles, vibro-compaction, cement-soil mixing, high-pressure jet grouting, or other methods that incorporate a certain amount of solidifying agent into the foundation or solidify the soil to achieve the purpose of reinforcing the foundation or improving its bearing capacity. However, in actual construction sites, various environmental factors often prevent the adoption of these construction methods.
[0003] In particular, when constructing new tunnels or other structures beneath existing superstructures, the construction space is constrained, and the height is insufficient to meet the operational requirements for construction machinery and vehicle transportation, greatly increasing the difficulty of treating soft foundations.
[0004] For example, lateral and central foundation piles are constructed first at depth in the soil layer. Column foundations are then built on these piles. Side columns are constructed on the foundations of the lateral and central foundation piles, and central columns are built on the foundations of the central foundation piles. Longitudinal and transverse bottom beams are then constructed above the side and central columns, and the existing superstructure is built on top of these beams. This entire structure is determined after the existing building has been constructed.
[0005] If a tunnel is to be constructed in the space below the longitudinal and transverse bottom beams and above the foundation (column foundation plane), the space is fixed and the height is insufficient for large construction vehicles to enter. Therefore, traditional methods cannot be used to reinforce the area between the side foundation piles and the central foundation piles. Without a reasonable and effective reinforcement method, tunnel construction within this limited space is impossible. Utility Model Content
[0006] In view of the technical problems existing in the prior art, the purpose of this utility model is to provide a structure for reinforcing the rigid pile foundation of a building in a limited space with composite foundation, which is simple in structure, easy to construct, and safe and reliable.
[0007] To achieve the above objectives, the present invention adopts the following technical solution:
[0008] Within a limited space, a composite foundation reinforcement structure is adopted for the rigid pile foundation of the structure. The existing structure on the top is supported by longitudinal and transverse bottom beams. The left and right sides of the longitudinal and transverse bottom beams are supported by two rows of side columns, and the middle is supported by a row of central columns. The side columns, column foundations, and side foundation piles are set in order from top to bottom, and the central columns, column foundations, and central foundation columns are set in order from top to bottom. A row of new foundation piles is constructed on the front and rear sides of the existing structure on the top. High-pressure jet grouting piles are evenly distributed within the rectangular space enclosed by the new foundation piles and side foundation piles to form a composite foundation within the rectangular space.
[0009] As a preferred option, the side foundation piles, middle foundation piles, and newly built foundation piles are all reinforced concrete cast-in-place piles; the side columns are ordinary reinforced concrete structural columns; and the middle columns are steel pipe columns.
[0010] As a preferred option, the diameter of the side foundation piles, the central foundation piles, and the newly built foundation piles is 1.5m.
[0011] As a preferred option, the composite foundation is divided into a standard section and a transition section; the transition section is located near the side piles, central piles, newly built piles and areas where pipelines are buried in the soil layer; the arrangement of high-pressure jet grouting piles in the transition section is denser than that in the standard section.
[0012] As a preferred method, the high-pressure jet grouting piles are arranged in a triangular pattern with a pile diameter of 60cm. In the standard section, the longitudinal and transverse spacing of the high-pressure jet grouting piles is 1.4m. In the transition section, the longitudinal spacing of the high-pressure jet grouting piles is 1.4m, and the transverse spacing is 1.2m. Three rows of piles are arranged in the width direction of the transition section. The longitudinal direction corresponds to the front-to-back direction, and the transverse direction corresponds to the left-to-right direction. The high-pressure jet grouting piles use a dual-pipe grouting method of cement grout and high-pressure air.
[0013] As a preferred option, the bearing stratum of the high-pressure jet grouting pile is a medium-coarse sand layer with an embedment depth of not less than 2m; or the bearing stratum of the high-pressure jet grouting pile is a strongly weathered silty mudstone with an embedment depth of not less than 1m.
[0014] As a preferred option, a gravel mattress layer is laid on top of the composite foundation.
[0015] As a preferred option, the crushed stone mattress layer uses graded crushed stone, which is laid in two layers: the first layer is 20cm thick, and the second layer is 15cm thick.
[0016] As a preferred option, the outer side of the side foundation piles is provided with graded slope, and the slope is made of 50mm wire mesh shotcrete.
[0017] As a preferred embodiment, the height H between the top surface of the foundation where the column foundation is located and the bottom of the longitudinal and transverse bottom beams is 6.5-7.0m, and the distance between the two rows of side columns and the row of middle columns is 16.5m.
[0018] The principle of this invention is to utilize the compact structure, small size, high mobility, and small footprint of high-pressure jet grouting pile construction equipment to reinforce weak foundations within a limited space. Existing rigid pile foundations (side piles and center piles) are used in conjunction with newly constructed piles and the high-pressure jet grouting pile composite foundation to share the load, ensuring the safety of constructing the new structure within a limited space.
[0019] This utility model has the following advantages:
[0020] 1. It can reinforce weak foundations in specific application scenarios, thus making it possible to construct building structures in limited spaces.
[0021] 2. It has a simple structure, strong practicality, is easy to construct, safe and reliable, and has a fast construction speed, which greatly improves the bearing capacity of soft soil foundation and provides a solid and stable foundation for the superstructure.
[0022] 3. By utilizing the existing rigid foundation (side piles and center piles) of the existing structure on the roof, the newly built foundation piles outside the confined space, and the high-pressure jet grouting pile composite foundation constructed within the confined space to share the load, the bearing capacity and seismic performance of the soft foundation under the condition of limited construction equipment in the confined space are greatly improved.
[0023] 4. High-pressure jet grouting piles use a dual-pipe grouting system of cement grout and high-pressure air, with a triangular pile arrangement, which allows the high-pressure jet grouting piles to form a continuous solidified body, effectively preventing groundwater seepage and improving the impermeability of the foundation.
[0024] 5. A two-layer uniform graded crushed stone cushion layer with a diameter not exceeding 20mm (20cm + 15cm) shall be set on the top of the pile. The graded crushed stone has good permeability, stress diffusion and load-bearing transition, can be sourced locally, facilitates the processing of raw materials and mixtures, and is easy to mechanically pave.
[0025] 6. In areas adjacent to existing rigid pile foundations (side piles and center piles), newly constructed rigid pile foundations (new foundation piles), and other pipelines, a transition section between rigid and flexible foundations is set up to increase the foundation stiffness, ensure a smooth transition between the two different types of foundations, and reduce stress concentration and uneven settlement caused by differences in foundation materials and mechanical properties.
[0026] 7. High-pressure jet grouting piles need to be embedded to a certain depth when constructed into the bearing layer, so that the jet grouting piles are focused on a solid stratum, increasing the contact area between the jet grouting piles and the foundation soil, thereby improving the bearing capacity and overall stability of the foundation, and reducing the deformation of the superstructure caused by uneven settlement of the foundation.
[0027] 8. In a limited space, a graded slope is set up, and the slope is sprayed with 50mm wire mesh and fine stone concrete, which can reduce the plane size of the slope excavation, protect the slope surface from rainwater erosion, prevent slope instability and collapse, and ensure the stability of the slope. Attached Figure Description
[0028] Figure 1 This is a structural diagram of the application scenario of this utility model.
[0029] Figure 2 This is a plan view of the pile layout of this utility model.
[0030] Figure 3 This is a schematic diagram of a structure with a transition section between a rigid foundation and a flexible foundation.
[0031] Figure 4 This is a schematic diagram of a high-pressure jet grouting pile embedded in the bearing layer.
[0032] Figure 5 This is a schematic diagram of a gravel mattress layer.
[0033] In the diagram, 1-side foundation pile, 2-middle foundation pile, 3-side column, 4-middle column, 5-column foundation, 6-newly built foundation pile, 7-existing structure on top, 8-high-pressure jet grouting pile, 9-crushed stone cushion layer, 10-slope, 11-flexible foundation area, 12-transition area between rigid and flexible foundation, 13-rigid foundation area, 14-bearing layer, 15-longitudinal and transverse bottom beams, 16-wire mesh sprayed fine stone concrete, 17-tunnel construction space. Detailed Implementation
[0034] The present invention will be further described in detail below with reference to specific embodiments.
[0035] Within a limited space, a composite foundation reinforcement structure is adopted for the rigid pile foundation of the structure. The existing structure on the top is supported by longitudinal and transverse bottom beams. The left and right sides of the longitudinal and transverse bottom beams are supported by two rows of side columns, and the middle is supported by a row of central columns. The side columns, column foundations, and side foundation piles are set in order from top to bottom, and the central columns, column foundations, and central foundation columns are set in order from top to bottom. A row of new foundation piles is constructed on the front and rear sides of the existing structure on the top. High-pressure jet grouting piles are evenly distributed within the rectangular space enclosed by the new foundation piles and side foundation piles to form a composite foundation within the rectangular space.
[0036] In this embodiment, the height between the top surface of the foundation and the longitudinal and transverse bottom beams below the existing structure is only 6.5-7.0m. Given the limited construction height within this confined space, the high-pressure jet grouting pile construction equipment is compact, small in size, highly mobile, and occupies little space. Furthermore, the vibration and noise of the construction equipment are minimal, preventing any impact on surrounding buildings. Secondly, high-pressure jet grouting piles are suitable for treating soil layers such as silt, silty soil, fluid plastic, soft plastic or plastic cohesive soil, plain fill, silt, sand, and gravelly soil, producing piles with high strength. Therefore, by adopting the high-pressure jet grouting pile technology, in... Figure 1 It is possible to construct a tunnel within the tunnel construction space 17 shown.
[0037] The side foundation piles, central foundation piles, and newly built foundation piles are all reinforced concrete cast-in-place piles; the side columns are ordinary reinforced concrete structural columns; and the central columns are steel pipe columns.
[0038] The diameter of the side foundation piles, central foundation piles, and newly built foundation piles is 1.5m.
[0039] The composite foundation is divided into a standard section and a transition section. The transition section is located near the side piles, central piles, newly built piles and areas where pipelines are buried in the soil. The high-pressure jet grouting piles in the transition section are arranged more densely than those in the standard section.
[0040] In this embodiment, corresponding Figure 3 The rigid and flexible foundation transition zone 12 shall be constructed in accordance with the requirements of the transition section, and the corresponding flexible foundation zone 11 shall be constructed in accordance with the requirements of the standard section.
[0041] The high-pressure jet grouting piles are arranged in a triangular pattern with a pile diameter of 60cm. In the standard section, the longitudinal and transverse spacing of the high-pressure jet grouting piles is 1.4m. In the transition section, the longitudinal spacing of the high-pressure jet grouting piles is 1.4m, and the transverse spacing is 1.2m. Three rows of piles are arranged in the width direction of the transition section. The longitudinal direction corresponds to the front and rear direction, and the transverse direction corresponds to the left and right direction. The high-pressure jet grouting piles use a dual-pipe grouting system of cement grout and high-pressure air.
[0042] In this embodiment, three rows of piles are arranged in the width direction of the transition section to increase the foundation stiffness.
[0043] In this embodiment, the average length of the solid piles in the high-pressure jet grouting piles is 14.1m, and the average length of the unfilled piles is 4.3m. The material used is 42.5 grade ordinary Portland cement, with a cement content of 280kg per meter. The water-cement ratio of the cement grout should be 0.8-1.2, the high-pressure cement grout pressure should be greater than 20MPa, and the pile strength at 28 days is 2.5MPa. The borehole position deviation of the high-pressure jet grouting piles should be ±50mm, and the allowable deviation in verticality should be ±1%.
[0044] In this embodiment, the high-pressure jet grouting pile is stationed at the junction of rock and soil (sand) where the soil properties may change significantly. This ensures that the grout fully penetrates and mixes, thereby enhancing the consolidation effect at this location, preventing void formation, and improving the shear strength of the soil and the overall stability and bearing capacity of the foundation.
[0045] The bearing stratum for high-pressure jet grouting piles is medium-coarse sand layer with an embedment depth of not less than 2m; or the bearing stratum for high-pressure jet grouting piles is strongly weathered silty mudstone with an embedment depth of not less than 1m.
[0046] In this embodiment, the high-pressure jet grouting piles need to be embedded to a certain depth in the bearing layer, thereby improving the bearing capacity and overall stability of the foundation.
[0047] A gravel mattress layer is laid on top of the composite foundation.
[0048] In this embodiment, after the high-pressure jet grouting pile construction is completed, two layers of graded crushed stone cushion layer are set on the pile top, which can disperse the load on the upper structure to a certain extent, slow down the occurrence of foundation settlement, reduce road vibration and noise, and improve driving comfort.
[0049] The crushed stone mattress layer uses graded crushed stone, which is laid in two layers: the first layer is 20cm thick, and the second layer is 15cm thick.
[0050] In this embodiment, an excavator is used to level the crushed stone, and the laid sand and gravel should be uniformly graded and the diameter should not exceed 20mm.
[0051] The outer side of the side foundation piles is provided with graded slope, and the slope is made of 50mm wire mesh shotcrete.
[0052] In this embodiment, the use of graded slope can reduce the planar dimensions of the slope excavation; at the same time, HPB300 grade steel mesh with a diameter of 6mm is hung on the slope, with an overlap length of more than 300mm between the steel meshes, and then 50mm fine stone concrete is sprayed to ensure the stability of the slope.
[0053] The height H between the top surface of the foundation where the column foundation is located and the bottom of the longitudinal and transverse bottom beams is 6.5-7.0m, and the distance between the two rows of side columns and the row of middle columns is 16.5m.
[0054] In addition to the methods mentioned in the above embodiments, the embedment depth of the bearing layer of the high-pressure jet grouting pile is preferably, but not necessarily, 1m and 2m, and can be adjusted accordingly based on the geological conditions of the bearing layer. The pile length of the high-pressure jet grouting pile is preferably, but not necessarily, an average pile length of 14.1m for solid piles and an average pile length of 4.3m for empty piles, and can be adjusted accordingly based on geological conditions, engineering requirements, and other factors. The pile spacing of the high-pressure jet grouting pile is preferably, but not necessarily, 1.2m and 1.4m, and can be adjusted accordingly based on soil type, soil strength, and expected reinforcement effect. The construction method of the high-pressure jet grouting pile is preferably, but not necessarily, a dual-pipe grouting method using cement grout and high-pressure air, and can be adjusted accordingly based on pile diameter and geological conditions. The cement content per meter is preferably, but not necessarily, 280kg, and can be adjusted accordingly based on the diameter, length, geological conditions, and water-cement ratio of the high-pressure jet grouting pile. The water-cement ratio of the cement grout is preferably, but not necessarily, 0.8-1.2, and can be adjusted accordingly based on the construction method and geological conditions. All these variations are within the protection scope of this utility model.
[0055] The above embodiments are preferred embodiments of the present utility model, but the embodiments of the present utility model are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present utility model shall be considered equivalent substitutions and shall be included within the protection scope of the present utility model.
Claims
1. A structure for reinforcing rigid pile foundations of a building within a confined space using a composite foundation, with the existing structure covered by longitudinal and transverse bottom beams. These beams are supported on both sides by two rows of side columns and in the middle by a row of central columns. The side columns, column foundations, and lateral foundation piles are arranged sequentially from top to bottom, as are the central columns, column foundations, and central foundation columns. The characteristic feature is that: A row of new foundation piles is constructed on both the front and rear sides of the existing structure on the top. High-pressure jet grouting piles are then constructed evenly within the rectangular space enclosed by the new foundation piles and the side foundation piles to form a composite foundation within the rectangular space.
2. The structure for reinforcing a rigid pile foundation of a building within a confined space using a composite foundation, as described in claim 1, is characterized in that: The side foundation piles, central foundation piles, and newly built foundation piles are all reinforced concrete cast-in-place piles; the side columns are ordinary reinforced concrete structural columns; and the central columns are steel pipe columns.
3. The structure for reinforcing a rigid pile foundation of a building within a confined space using a composite foundation, as described in claim 2, is characterized in that: The diameter of the side foundation piles, central foundation piles, and newly built foundation piles is 1.5m.
4. The structure for reinforcing a rigid pile foundation of a building within a confined space using a composite foundation, as described in claim 1, is characterized in that: The composite foundation is divided into a standard section and a transition section. The transition section is located near the side piles, central piles, newly built piles and areas where pipelines are buried in the soil. The high-pressure jet grouting piles in the transition section are arranged more densely than those in the standard section.
5. The structure for reinforcing a rigid pile foundation of a building within a confined space using a composite foundation, as described in claim 4, is characterized in that: The high-pressure jet grouting piles are arranged in a triangular pattern with a pile diameter of 60cm. In the standard section, the longitudinal and transverse spacing of the high-pressure jet grouting piles is 1.4m. In the transition section, the longitudinal spacing of the high-pressure jet grouting piles is 1.4m, and the transverse spacing is 1.2m. Three rows of piles are arranged in the width direction of the transition section. The longitudinal direction corresponds to the front and rear direction, and the transverse direction corresponds to the left and right direction. The high-pressure jet grouting piles use a dual-pipe grouting system of cement grout and high-pressure air.
6. The structure for reinforcing a rigid pile foundation of a building within a confined space using a composite foundation, as described in claim 1, is characterized in that: The bearing stratum for high-pressure jet grouting piles is medium-coarse sand layer with an embedment depth of not less than 2m; or the bearing stratum for high-pressure jet grouting piles is strongly weathered silty mudstone with an embedment depth of not less than 1m.
7. The structure for reinforcing a rigid pile foundation of a building within a confined space using a composite foundation, as described in claim 1, is characterized in that: A gravel mattress layer is laid on top of the composite foundation.
8. The structure for reinforcing a rigid pile foundation of a building within a confined space using a composite foundation, as described in claim 7, is characterized in that: The crushed stone mattress layer uses graded crushed stone, which is laid in two layers: the first layer is 20cm thick, and the second layer is 15cm thick.
9. The structure for reinforcing a rigid pile foundation of a building within a confined space using a composite foundation, as described in claim 1, is characterized in that: The outer side of the side foundation piles is provided with graded slope, and the slope is made of 50mm wire mesh shotcrete.
10. The structure for reinforcing a rigid pile foundation of a building within a confined space using a composite foundation, as described in claim 1, is characterized in that: The height H between the top surface of the foundation where the column foundation is located and the bottom of the longitudinal and transverse bottom beams is 6.5-7.0m, and the distance between the two rows of side columns and the row of middle columns is 16.5m.