An inclined pile bracing structure for retaining walls

Abstract

This utility model discloses an inclined pile support structure for retaining walls, comprising three parts: a retaining wall, a beam, and an inclined pile support. The beam is a reinforced concrete structure located at the top of the retaining wall. The upper end of the inclined pile support is a steel pipe pile, and the lower end is a high-pressure jet grouting pile. The high-pressure jet grouting pile is located below the foundation pit surface. The upper end of the steel pipe pile is anchored into the beam, and the lower end is inserted into the high-pressure jet grouting pile. A first sealing steel plate plug is installed at the upper end of the steel pipe pile, and a second sealing steel plate plug is installed at the lower end of the steel pipe pile. The second sealing steel plate plug is provided with grouting holes. A waterproof steel plate is welded around the steel pipe pile at the cross-shaped steel plate pile tip located in the foundation pit. The waterproof steel plate is fixed in the foundation pit layer. The lower end of the steel pipe pile is a spherical grout bubble.

Description

Technical Field

[0001] This utility model belongs to the field of foundation pit support, and particularly relates to an inclined pile support structure for foundation pit engineering in soft soil areas. Background Technology

[0002] In foundation pit support engineering in soft soil areas, using inclined pile bracing instead of internal bracing offers advantages such as faster construction speed, lower project cost, and energy conservation and environmental protection. However, some existing inclined pile bracing methods involve mixing or static pressure insertion, which can lead to insufficient equipment power or reaction force, resulting in limitations on pile diameter or length. Other methods involve injecting cement grout to expand the pile diameter, but this requires a large amount of cement and the expansion effect is difficult to guarantee. All of these factors contribute to low axial bearing capacity of single piles. Furthermore, during the foundation pit excavation stage, the exposed sections of the inclined pile bracing are susceptible to damage from excavators, increasing the safety risks of the foundation pit. Summary of the Invention

[0003] This utility model aims to solve the technical problems of low axial bearing capacity and weak impact resistance of existing inclined pile bracing single piles.

[0004] This utility model is achieved by the following technical solution: a inclined pile support structure for retaining walls, comprising three parts: retaining wall, beam, and inclined pile support. The beam is a reinforced concrete structure located at the top of the retaining wall. The upper end of the inclined pile support is a steel pipe pile, and the lower end is a high-pressure jet grouting pile. The high-pressure jet grouting pile is located below the foundation pit surface. The upper end of the steel pipe pile is anchored into the beam, and the lower end is placed inside the high-pressure jet grouting pile. An annular connecting block is formed between the steel pipe pile and the high-pressure jet grouting pile. The connecting block has a wavy toothed structure. A first sealing steel plate plug is installed at the upper end of the steel pipe pile, and a second sealing steel plate plug is installed at the lower end of the steel pipe pile. The second sealing steel plate plug is provided with grouting holes. A waterproof steel plate is welded around the steel pipe pile at the cross-shaped steel plate pile tip located in the foundation pit. The waterproof steel plate is fixed in the foundation pit layer. The lower end of the steel pipe pile is a spherical grout bubble.

[0005] The inclination angle of the inclined pile bracing is 40°~50°.

[0006] The first sealing steel plate plug is equipped with a grouting pipe, a grouting valve, an exhaust pipe, and an exhaust valve.

[0007] The steel pipe pile is fitted with a grouting pipe, filled with crushed stone, and then injected with cement grout.

[0008] The retaining wall is one of the following: pile wall, cast-in-place concrete pile, steel pile, steel pipe pile, steel sheet pile, steel-cement-soil mixing pile, or diaphragm wall.

[0009] The features of this utility model are: using a more mature and controllable high-pressure jet grouting pile to simultaneously achieve pre-drilling and pile diameter expansion; forming spherical grout bubbles at the pile end through compaction grouting to improve the soil strength at the pile end and further improve the single pile bearing capacity; and strengthening the rigidity of the steel pipe pile by filling it with crushed stone and injecting cement grout to avoid damage from excavator contact. Attached Figure Description

[0010] Figure 1 This is a schematic diagram of an inclined pile support structure for retaining walls according to the present invention.

[0011] Figure 2 This is a schematic cross-sectional view of the sealing steel plate structure at the upper end of the steel pipe pile of this utility model.

[0012] Figure 3 This is a schematic diagram of the upper sealing steel plate structure of the steel pipe pile of this utility model.

[0013] Figure 4 This is a cross-sectional schematic diagram of the sealing steel plate structure at the lower end of the steel pipe pile of this utility model.

[0014] Figure 5 This is a schematic plan view of the sealing steel plate structure at the lower end of the steel pipe pile according to this utility model. Detailed Implementation

[0015] The features of this utility model will be further described in detail below with reference to the accompanying drawings and embodiments:

[0016] As attached Figure 1 1- Retaining wall; 2- Beam; 3- Steel pipe pile; 4- Crushed stone and injected cement grout; 5- High-pressure jet grouting pile; 6- First sealing steel plate plug; 7- Second sealing steel plate plug; 8- Spherical grout bubble; 9- Grouting pipe; 10- Exhaust pipe; 11- Grouting valve; 12- Exhaust valve; 13- Grouting hole; 14- Cross-shaped steel sheet pile tip.

[0017] Example: Figure 1 As shown, this embodiment specifically relates to an inclined pile support structure and its construction method. The retaining structure is formed by combining 1-retaining wall, 2-beam, 3-steel pipe pile, 4-crushed stone and injected cement grout, and 5-high pressure jet grouting pile.

[0018] First, construct the retaining wall 1, excavating to the top of the retaining wall.

[0019] 5. High-pressure jet grouting piles are constructed by setting the drilling rig on the ground and drilling the drill rod at an angle of 40°~50° in the soil layer below the bottom of the foundation pit. The selection of jet grouting pile methods is shown in the table below. The single-pipe method uses a high-pressure mud pump to impact and break the soil at a pressure greater than 20MPa to form a consolidated body; the double-pipe method uses a high-pressure mud pump or similar device to spray grout at a high speed from the inner nozzle at a pressure greater than 20MPa, and compressed air at a pressure of about 0.7MPa is sprayed from the outer nozzle; the triple-pipe method uses a high-pressure pump to generate a high-pressure water jet stream greater than 20MPa, which surrounds a stream of air at about 0.7MPa to cut through the soil, creating larger pores, which are then filled with grout at a pressure of 2MPa~5MPa to form a consolidated body. The lifting speed of high-pressure jet grouting piles is 0.05m / min~0.25m / min, and the water-cement ratio is 0.8~1.5, with 1.0 being commonly used. Table 1 Selection Table for Jet Grouting Pile Methods

[0020] 3-The steel pipe pile is inserted into the cement-soil at a 40°~50° angle along the borehole of the 5-high-pressure jet grouting pile, with its bottom flush with the bottom of the cement-soil. Multiple sections of steel pipe are connected by welding or threading. Specifically, a 7-sealing steel plate plug is welded to the bottom of the steel pipe pile, and the 7-sealing steel plate plug has a pre-drilled 13-grouting hole, with a 14-cross-shaped steel sheet pile tip welded on top. After the 3-steel pipe pile is installed in place, a 10-grouting pipe is inserted inside, with multiple sections of grouting pipe connected by threading. Then, crushed stone is filled into the 3-steel pipe pile up to the top. A 6-sealing steel plate plug is installed on the top of the 3-steel pipe pile, and a 9-grouting pipe, a 10-vent pipe, an 11-grouting valve, and a 12-vent valve are installed on the 6-sealing steel plate plug.

[0021] Open 11-grouting valve and 12-vent valve, and inject cement grout through 9-grouting pipe. The grouting pressure should be 0.2~0.3MPa, and the water-cement ratio is usually 1.0. Grout until the cement grout gushes out from 10-vent pipe, close 12-vent valve, and continue grouting to the designed cement dosage to form 8-spherical grout bubbles at the bottom of the pile. Then close 11-grouting valve.

[0022] Finally, beam 2, a reinforced concrete structure, is constructed to connect to retaining wall 1 and anchor steel pipe piles 3, working together to balance earth pressure. The foundation pit is excavated after the inclined pile bracing structure meets strength requirements.

[0023] This invention utilizes 5-high-pressure jet grouting piles to ensure the required inclined pile diameter, providing frictional resistance. Grouting at the pile tip forms spherical grout bubbles, further enhancing end-pile resistance. This, in turn, increases the bearing capacity of a single pile. Furthermore, filling the pile hole with crushed stone and injecting cement grout improves the stiffness of the 3-steel pipe piles, reducing the probability of damage and increasing the safety of the foundation pit project.

Claims

1. A inclined pile bracing support structure for retaining walls, characterized in that: The structure comprises three parts: a retaining wall, a beam, and inclined pile supports. The beam is a reinforced concrete structure located at the top of the retaining wall. The inclined pile supports consist of steel pipe piles at the upper end and high-pressure jet grouting piles at the lower end, with the high-pressure jet grouting piles located below the foundation pit surface. The upper end of the steel pipe pile is anchored into the beam, and the lower end is inserted into the high-pressure jet grouting pile. An annular connecting block with a wavy toothed structure is formed between the steel pipe pile and the high-pressure jet grouting pile. A first sealing steel plate plug is installed at the upper end of the steel pipe pile, and a second sealing steel plate plug is installed at the lower end. The second sealing steel plate plug has grouting holes. A waterproof steel plate is welded around the steel pipe pile at the cross-shaped steel plate pile tip located in the foundation pit. The waterproof steel plate is fixed in the foundation pit layer. The lower end of the steel pipe pile has a spherical grout bubble.

2. The inclined pile bracing support structure for retaining walls according to claim 1, characterized in that, The inclination angle of the inclined pile bracing is 40°~50°.

3. The inclined pile bracing support structure for retaining walls according to claim 1, characterized in that, The first sealing steel plate plug is equipped with a grouting pipe, a grouting valve, an exhaust pipe, and an exhaust valve.

4. The inclined pile bracing support structure for retaining walls according to claim 1, characterized in that, The steel pipe pile is fitted with a grouting pipe, filled with crushed stone, and then injected with cement grout.

5. The inclined pile bracing support structure for retaining walls according to claim 1, characterized in that, The retaining wall is one of the following: pile wall, cast-in-place concrete pile, steel pile, steel pipe pile, steel sheet pile, steel-cement-soil mixing pile, or diaphragm wall.

Images