A seepage prevention structure for pile foundations on the inner side of an overpass embankment

Abstract

This utility model relates to the field of geotechnical engineering for elevated bridge embankments, and more particularly to a seepage prevention structure for the inner pile foundation of an elevated bridge embankment. A seepage prevention curtain is arranged around the pile foundation. This curtain is constructed using a high-pressure jet grouting method, forming a ring of multiple interlocking consolidated composite bodies around the pile foundation. This structure blocks water from forming seepage channels around the pile foundation, thus preventing groundwater from seeping out through these channels. The high-pressure jet grouting process around the pile allows for flexible control over the reinforcement depth and grouting volume, resulting in good seepage prevention. It is suitable for various soil layers and has strong versatility. The technology is mature, the steps are simple, and it offers economic advantages. This utility model solves the technical problem of effectively reinforcing potential seepage channels, improving its versatility while ensuring the quality of construction results, and simplifying the process and reducing costs.

Description

Technical Field

[0001] This utility model relates to the field of geotechnical engineering of viaduct embankments, and in particular to a seepage prevention structure for the inner pile foundation of a viaduct spanning an embankment. Background Technology

[0002] Seepage prevention of dikes is a crucial component of the entire road-embankment integrated project. Only by implementing effective seepage prevention measures can the safety and reliability of the dikes be guaranteed, and the service life of the water conservancy project be extended. For most projects, leakage problems are often caused by concentrated seepage channels formed by large pores. Successfully locating and sealing these concentrated seepage channels can essentially solve the leakage problem. During the construction of pile foundations on the inner side of the dike, seepage channels often form at the interface between the pile foundation and the soil layer. Groundwater seeps out along these channels, seriously threatening the stability of the pile foundation and the safety of the superstructure.

[0003] Currently, common pile foundation seepage prevention technologies include the following: ① Splitting grouting seepage prevention: This technology uses grouting pressure to split the soil, then injects grout into the soil. After the grout solidifies, it can achieve the seepage prevention effect of the pile foundation. However, in situations with complex geological conditions, high groundwater levels, and large stratum porosity, groundwater flow can carry away the grout, resulting in high material consumption, difficulty in control, and potential environmental pollution, making it difficult to guarantee quality. ② Using dual-liquid grouting with fast grout setting speed: Although this can reduce grout setting time and reduce excessive grout loss and waste, it is expensive. ③ Clay backfill seepage prevention: Combined with composite geomembranes, this can effectively improve the seepage prevention capacity of the project. Composite geomembranes are lightweight and easy to transport, offering good economic benefits. However, this technology requires replacing the existing dikes and burying the composite geomembrane. Clay backfilling and compaction around the bridge piles is difficult, and the compaction degree cannot be guaranteed. During construction, a composite geomembrane needs to be laid around the pile foundation to form a complete seepage prevention system, and anchoring grooves are designed on the pile foundation to ensure the firmness and stability of the composite geomembrane. The construction process is relatively complex and requires a large amount of manpower.

[0004] The above-mentioned pile foundation seepage prevention measures have the following disadvantages: the construction quality may be affected by the construction stratum conditions and groundwater conditions, or there may be potential threats to the environment, or the construction process may be complex and the cost may be high. Utility Model Content

[0005] The purpose of this utility model is to provide a seepage prevention structure for the inner pile foundation of an overpass bridge, which can solve the technical problem of how to effectively reinforce the seepage channel area, improve its universality, simplify the process and reduce the cost while ensuring the quality of the construction results.

[0006] To achieve the above objectives, this utility model provides the following technical solution: This utility model discloses a seepage prevention structure for the inner pile foundation of an elevated bridge spanning a dike. It includes bridge columns, abutments, and pile foundations arranged sequentially from top to bottom. A seepage prevention curtain is arranged around the pile foundation. The seepage prevention curtain is composed of multiple interlocking consolidation composites formed around the pile foundation by high-pressure jet grouting. It is used to block water from forming seepage channels around the pile foundation, thereby preventing groundwater from seeping out along these seepage channels.

[0007] As a preferred embodiment, the solidified composite has a layered structure, comprising, from the outside to the inside, a permeation and condensation layer, an extrusion layer, a stirring and mixing layer, and a core body layer.

[0008] Furthermore, the permeation coagulation layer, extrusion layer, mixing layer, and core main body layer are all composed of cement slurry.

[0009] Furthermore, the density of the extrusion layer and the mixing layer is greater than that of the permeation and condensation layer, and the impermeability of the extrusion layer and the mixing layer is stronger than that of the permeation and condensation layer.

[0010] Furthermore, the thickness of the core main body layer is greater than the thickness of the permeation condensation layer, the extrusion layer, and the stirring and mixing layer, respectively.

[0011] As a preferred option, multiple consolidated composites are arranged in a quincunx pattern around the pile foundation.

[0012] The beneficial effects of this utility model are: This utility model provides a seepage prevention structure for the inner pile foundation of a viaduct across a levee. A seepage prevention curtain is arranged around the pile foundation. The seepage prevention curtain is composed of multiple interlocking consolidation composites formed around the pile foundation by high-pressure jet grouting. It is used to block the water from forming a seepage channel around the pile foundation, thereby preventing groundwater from seeping out along this seepage channel.

[0013] ① The high-pressure jet grouting process is used around the piles, which allows for flexible control over the reinforcement depth and grouting volume. The reinforced body has a good seepage prevention effect and is suitable for various soil layers, making it highly versatile. ②When there are mixing piles and existing pipelines near the pile foundation, the seepage prevention technology of this utility model can minimize the impact on the existing structure, reduce costs, and shorten the construction period; ③ This utility model uses high-pressure jet grouting technology to treat the pile foundation for seepage prevention. The technology is mature, the steps are simple, and it has economic advantages. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the present invention.

[0015] Figure 2 This is a cross-sectional schematic diagram of a pile foundation seepage prevention structure.

[0016] Figure 3This is a plan layout of the pile foundation seepage prevention structure.

[0017] Explanation of reference numerals in the attached figures: 1-Bridge column; 2-Ground line; 3-Pile cap; 4-Anti-seepage curtain; 5-Pile foundation; 6-Consolidated composite; 7-Center position line of consolidated composite; 6-Consolidated composite: 6.1-Permeation and condensation layer; 6.2-Extrusion layer; 6.3-Stirring and mixing layer; 6.4-Core main body layer. Detailed Implementation

[0018] To make the technical problem solved by this utility model, the technical solution adopted, and the technical effect achieved clearer, the technical solution of this utility model will be further described below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only for explaining this utility model and not for limiting it. Furthermore, it should be noted that, for ease of description, only the parts related to this utility model are shown in the accompanying drawings, not all of them.

[0019] In the description of this utility model, 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 this utility model 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 this utility model. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance. Specifically, the terms "first position" and "second position" refer to two different positions.

[0020] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to fixed connections or detachable connections; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; and internal connections between two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0021] This utility model relates to the field of geotechnical engineering, specifically to a seepage prevention structure for the inner pile foundation of viaducts spanning embankments, applicable to seepage prevention treatment of bridge pile foundations on the inner side of embankments. The fundamental issue in pile foundation seepage prevention lies in how to effectively reinforce and prevent seepage at potential seepage channels, improving its versatility while ensuring the quality of construction results, simplifying the process, and reducing costs. Therefore, researching a new seepage prevention process with the aforementioned advantages is essential. This utility model, problem-oriented, comprehensively considers various common pile foundation seepage prevention processes and pile foundation seepage principles, proposing a novel seepage prevention treatment measure for the inner pile foundation of viaducts on embankments, including process layout and key construction points. The seepage prevention treatment measure proposed in this utility model can effectively improve the seepage prevention performance of the soil surrounding the pile foundation, ensuring the safety and stability of the superstructure. Addressing the problem of pile foundation leakage, starting from the causes of seepage formation, effectively reinforcing and preventing seepage at potential seepage channels, improving its versatility while ensuring the quality of construction results, simplifying the process, and reducing costs are the main problems solved by this utility model.

[0022] This utility model provides a seepage prevention structure for the inner pile foundation of an elevated bridge spanning a dike. It includes, from top to bottom, bridge columns 1, pile caps 3, and pile foundations 5. A seepage prevention curtain 4 is arranged around the pile foundations 5. The seepage prevention curtain 4 is constructed using a high-pressure jet grouting method, forming a ring of multiple interlocking consolidated composite bodies 6 around the pile foundations 5. This curtain blocks water from forming seepage channels around the pile foundations 5, thereby preventing groundwater from seeping out through these channels. The multiple consolidated composite bodies 6 are arranged in a quincunx pattern around the pile foundations 5.

[0023] The consolidated composite 6 has a layered structure, comprising, from the outside to the inside, a permeable setting layer 6.1, an extrusion layer 6.2, a mixing layer 6.3, and a core main layer 6.4. All layers are composed of cement slurry. The density of the extrusion layer 6.2 and the mixing layer 6.3 is greater than that of the permeable setting layer 6.1, and their impermeability is stronger. The thickness of the core main layer 6.4 is greater than that of the permeable setting layer 6.1, the extrusion layer 6.2, and the mixing layer 6.3.

[0024] The technical solution of this utility model will be further described below with reference to the accompanying drawings and specific embodiments.

[0025] This utility model is applicable to seepage prevention treatment of pile foundations for bridges spanning dikes. All pile foundations within 100m of the river-facing side of the dike (or seepage barrier) require seepage prevention treatment. The treatment scheme is as follows: multiple pile foundations 5 are arranged at intervals below the pile cap 3, and multiple consolidated composite structures are arranged in a quincunx pattern around the perimeter of each pile foundation 5 to form a seepage barrier curtain 4. The seepage barrier curtain 4 is tightly fitted to the pile foundation 5. Figure 2 ,3 As shown. This seepage-proof structure can block the formation of seepage channels by water around the pile foundation, thereby preventing groundwater from seeping out along these channels.

[0026] The cross-sectional structure of a single consolidated composite body formed around the pile foundation by high-pressure jet grouting is as follows: Figure 1 As shown, the high-pressure jet grouting method involves spraying cement grout from the nozzle upwards in a layered structure. The outermost layer, furthest from the nozzle, has a lower density and higher permeability than the inner layers. Once the grouting pipe penetrates the soil and the nozzle reaches the design elevation, grouting can begin according to the determined construction parameters. The grouting pipe is then raised, and grouting continues from the bottom up. The stopping point should ideally be 1 meter above the designed top surface of the anti-seepage curtain.

[0027] Each consolidated composite is a cylindrical layered structure, consisting of, from the outside in, a permeable setting layer 6.1, an extrusion layer 6.2, a mixing layer 6.3, and a core main layer 6.4. All three layers—permeable setting layer 6.1, extrusion layer 6.2, mixing layer 6.3, and core main layer 6.4—are composed of cement grout. The density of extrusion layer 6.2 and mixing layer 6.3 is greater than that of permeable setting layer 6.1, and their impermeability is stronger. The thickness of core main layer 6.4 is greater than that of permeable setting layer 6.1, extrusion layer 6.2, and mixing layer 6.3, respectively.

[0028] The seepage water first passes through the permeable coagulation layer 6.1, then enters the more impermeable compression layer 6.2 and the mixing layer 6.3, and finally enters the core grout layer 6.4. If a complete seepage process occurs, the water must overflow the seepage channel in the reverse order, entering the mixing layer 6.3 and the compression layer 6.2 sequentially from the core grout layer 6.4, and finally passing through the permeable coagulation layer 6.1. This complex water flow seepage process further reduces the soil's permeability coefficient, increasing its impermeability. Furthermore, the overlapping and interlocking of multiple consolidated composite layers further enhances the soil's impermeability. Figure 3 As shown, the diameter of the consolidated composite 6 is φ800mm; the diameter of the central circle formed by the center position line 7 of the consolidated composite is φ1400mm; and the diameter of the pile foundation 5 is φ1000mm.

[0029] The construction process of this pile foundation seepage prevention structure is as follows: 1) Multiple consolidation composites 6 are set up in a quincunx pattern around the perimeter of the pile foundation 5 to form a seepage prevention curtain that is tightly attached to the pile foundation 5. Each consolidation composite is 5.5m long (adjustable). The grouting surface of the seepage prevention jet grouting pile should be 50cm higher than the bottom surface of the pile cap. When constructing the pile cap, the consolidation composite is broken up by 50cm to ensure that the newly poured concrete is tightly connected to the consolidation composite, thereby ensuring the seepage prevention effect.

[0030] 2) For the abutment, first construct the pile foundation, then the consolidated composite, then the mixing piles under the reinforced soil retaining wall, and finally the abutment, the bridge superstructure and the roadbed filling.

[0031] 3) For the remaining parts, first construct the pile foundation, then the consolidation composite, then the pier cap, and finally the bridge superstructure.

[0032] 4) Adding 2%–4% water glass to ordinary silicate cement grout can significantly improve the impermeability of the consolidated body. When the project aims for seepage prevention, a "flexible material" should be added, such as 10%–50% (by weight) bentonite to the cement grout. The permeability coefficient of the consolidated composite is less than 1.0 × 10⁻⁶. -6 cm / s, 28-day unconfined compressive strength not less than 2.0 MPa.

[0033] The specific construction points are as follows: (1) Material preparation: The pile foundation perimeter consolidation composite curtain of this utility model requires fresh, lumpy, 42.5MPa ordinary Portland cement. The water-cement ratio of the cement slurry is 0.9~1.1, and the cement dosage is ≥35%. Appropriate amounts of quick-setting, suspending or antifreeze admixtures and additives may be added as needed.

[0034] (2) Test pile construction: Before construction, a pile test must be conducted to test the cement-soil mix ratio, verify whether the unconfined compressive strength of the pile body and the permeability coefficient of the seepage barrier meet the seepage prevention requirements, and determine the construction process and parameters of the jet grouting pile. There should be no less than 3 test points. Each test point should form a seepage barrier with an axial length of 3 to 5 m.

[0035] (3) Construction of high-pressure jet grouting anti-seepage curtain around the pile foundation: This utility model adopts the double-pipe jet grouting method for the construction of high-pressure jet grouting anti-seepage curtain around the pile foundation. The process is as follows: measurement and positioning → equipment positioning → drilling and hole making → pipe lowering and jetting → grout jetting → jet grouting and lifting → pile formation.

[0036] (4) Inspection of seepage prevention effect: Select key locations for on-site water injection pressure testing. The hole diameter and depth are selected according to the actual site conditions. If the average permeability coefficient of the high-pressure jet seepage prevention curtain is less than 1.0×10 -6 If the speed is cm / s, then the requirements for pile foundation seepage prevention are met.

[0037] All other undescribed parts belong to the prior art. The above-described embodiments only illustrate several implementation methods of this utility model, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of this utility model patent. It should be noted that for those skilled in the art, several modifications and improvements can be made without departing from the concept of this utility model, and these all fall within the protection scope of this utility model. Therefore, the protection scope of this utility model patent should be determined by the appended claims.

Claims

1. A kind of suitable for the anti-seepage structure of pile foundation inside embankment of viaduct embankment across dike, it is characterized in that: The bridge includes a bridge column (1), a pier (3), and a pile foundation (5) arranged from top to bottom. A seepage prevention curtain (4) is arranged around the pile foundation (5). The seepage prevention curtain (4) is composed of multiple interlocking solidified composite bodies (6) formed around the pile foundation (5) by high-pressure jet grouting. It is used to block water from forming a seepage channel around the pile foundation (5), thereby preventing groundwater from seeping out along this seepage channel.

2. The seepage prevention structure for the inner side of the embankment of an elevated bridge across a dike, as described in claim 1, is characterized in that: The solidified composite (6) has a layered structure, including a permeation condensation layer (6.1), an extrusion layer (6.2), a stirring and mixing layer (6.3), and a core main body layer (6.4) arranged sequentially from the outside to the inside.

3. A seepage prevention structure for the inner side of a pile foundation of a viaduct spanning a dike, as described in claim 2, is characterized in that: The permeation coagulation layer (6.1), the extrusion layer (6.2), the mixing layer (6.3), and the core main body layer (6.4) are all composed of cement slurry.

4. A seepage prevention structure for the inner side of a pile foundation of a viaduct spanning a dike, as described in claim 3, is characterized in that: The density of the extrusion layer (6.2) and the mixing layer (6.3) is greater than that of the permeation condensation layer (6.1), and the seepage prevention performance of the extrusion layer (6.2) and the mixing layer (6.3) is stronger than that of the permeation condensation layer (6.1).

5. A seepage prevention structure for the inner side of a pile foundation of a viaduct spanning a dike, as described in claim 4, is characterized in that: The thickness of the core main layer (6.4) is greater than the thickness of the permeation condensation layer (6.1), the extrusion layer (6.2), and the stirring and mixing layer (6.3), respectively.

6. A seepage prevention structure for the inner side of a pile foundation of a viaduct spanning a dike, as described in any one of claims 1 to 5, characterized in that: Multiple consolidated composites (6) are arranged in a quincunx pattern around the pile foundation (5).

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