CN203684204U - Plastic flow soft foundation reinforced structure - Google Patents

Abstract

A flow-plastic soft soil foundation reinforcement structure can effectively resist dynamic loads, improve the shear strength of CFG piles, and expand the application range of CFG piles. The reinforcement structure includes bored pressure-grouting plain concrete piles (10) arranged longitudinally and horizontally at intervals in the flow-plastic soft soil layer, and a cushion layer laid on the top surface of the bored pressure-grouting plain concrete piles (10), the foundation ( 30) Constructed on the mattress layer. The surface of the bored pressure grouting plain concrete pile (10) is wrapped with a geotextile inner sleeve (11), and the surface of the geotextile inner sleeve (11) is wrapped with a bonded geogrid outer sleeve (12).

Description

A flow-plastic soft soil foundation reinforcement structure

technical field

The utility model relates to civil engineering, in particular to a flow-plastic soft soil foundation reinforcement structure.

Background technique

Flow-plastic soft soil is widely distributed in the coastal areas of our country. It has high water content, some even exceed 100%, large soil void ratio, high compressibility, and the volume of pores in some soils reaches 25% of the solid volume. Times, high sensitivity, low shear strength, generally no more than 5kPa, prone to creep and other characteristics.

When dealing with flexible piles, the strength of the soil around the piles is too low to provide sufficient lateral restraint, and lateral swelling occurs, resulting in failure of the entire composite foundation.

When semi-rigid piles, such as drilled and grouted plain concrete piles (CFG piles) reinforce the flow-plastic layer, especially the inclined flow-plastic layer, they are subject to dynamic loads (such as the influence of the piles that are pouring sinking tubes around the piles on the piles that have been constructed, subgrade vehicle load, earthquake load, etc.), it is very easy to suffer the shear force given to it by the soil and break the pile. In addition, in the deep soft soil layer, it is often necessary to drive the pile to a deeper soil layer, and the CFG pile is due to its The shear strength is low, and broken piles often occur, and the pile length can usually only be designed as 10-15m.

When processing rigid piles, such as prestressed pipe piles and cement mixing piles, the pore water is not easy to dissipate, and because it is rigidly connected to the building, once an earthquake occurs, the vibration of the construction pile will be directly involved in the vibration of the building body, so its earthquake resistance Performance is poor. And the cost of prestressed pipe pile is high.

To sum up, among the existing reinforcement measures for flow-plastic soft soil foundation, flexible piles are not strong enough to deal with flow-plastic soft soil, while rigid piles are not easy to drain and the cost is too high.

Utility model content

The technical problem to be solved by the utility model is to provide a flow-plastic soft soil foundation reinforcement structure, which can effectively resist dynamic loads, improve the shear strength of CFG piles, and expand the application range of CFG piles.

The technical scheme adopted by the utility model to solve the above-mentioned technical problems is: a flow-plastic soft soil foundation reinforcement structure of the utility model, which includes bored pressure-grouting plain concrete arranged longitudinally and horizontally in the flow-plastic soft soil layer Pile, and the mattress layer laid on the top surface of the bored pressure-grown concrete pile, the foundation is built on the mattress layer, and it is characterized in that: the surface of the drilled pressure-grown concrete pile is wrapped with a geotextile inner sleeve, The surface of the inner sleeve of the geotextile is wrapped with the outer sleeve of the bonded geogrid.

The mattress layer is composed of a lower mattress layer, a geogrid layer and an upper mattress layer laid in sequence.

The utility model has the following beneficial effects: the pore water can be discharged in time along the geogrid outside the pile, which can greatly improve the shear strength of the CFG pile, and is beneficial to the dissipation of the pore water pressure during the earthquake load; Under the radial constraint of the outer sleeve of the geogrid, the stiffness of the pile body is greatly improved. Due to the increase in the shear strength of the CFG pile, the CFG pile can be designed to be longer and embedded in the stable underlying layer, thereby improving the pile strength. Excellent side friction resistance and end bearing capacity, and can effectively reduce deformation, which can greatly expand the application range of CFG piles; the inner sleeve of geotextile can prevent the necking and pile body from being filled with silt during the pile forming process. As well as pile quality problems such as water inflow during pile sinking, to prevent the erosion of the pile body by surrounding corrosive substances and improve the durability of CFG piles; the outer surface of the outer sleeve of the geogrid is rough, which is conducive to the exertion of side friction resistance; The geogrid layer set in the layer can reinforce the foundation horizontally and reduce the differential settlement; the construction is simple and saves money, and the inner sleeve of the geotextile and the outer sleeve of the geogrid can be produced uniformly in the factory, and the cost is not high. high.

Description of drawings

This manual includes the following five drawings:

Fig. 1 is a cross-sectional schematic diagram of a flow-plastic soft soil foundation reinforcement structure of the utility model;

Fig. 2 is the enlarged schematic diagram of part A in Fig. 1;

Fig. 3 is the enlarged schematic diagram of part B in Fig. 1;

Fig. 4 is a schematic diagram of drainage of a flow-plastic soft soil foundation reinforcement structure of the present invention, and the arrow in the soil indicates the drainage direction;

Fig. 5 is a detailed schematic diagram of a flow-plastic soft soil foundation reinforcement structure along the outer edge of the pile according to the utility model.

Components, part names and corresponding marks in the figure: bored grouting plain concrete pile 10, geotextile inner sleeve 11, geogrid outer sleeve 12, upper mattress 21, lower mattress 22, geogrid Gate layer 23, foundation 30.

Detailed ways

Below in conjunction with accompanying drawing and embodiment the utility model is further described.

With reference to Fig. 1, a kind of flow-plastic shape soft soil foundation reinforcement structure of the present utility model comprises the borehole pressure-grouting plain concrete pile 10 that is arranged in the flow-plastic shape soft soil layer at intervals longitudinally and transversely, and lays on the borehole pressure-grouting pile 10. The cushion layer on the top surface of the plain concrete pile 10, and the foundation 30 is built on the cushion layer. Referring to FIG. 3 , the surface of the bored pressure grouting plain concrete pile 10 is wrapped with a geotextile inner sleeve 11 , and the surface of the geotextile inner sleeve 11 is wrapped with a bonded geogrid outer sleeve 12 .

Referring to Fig. 3, the inner sleeve 11 of the geotextile is wrapped along the full length of the bored pressure grouting plain concrete pile 10, and the bottom end is sealed, which has the functions of isolation, waterproof, anti-corrosion and reinforcement. The bottom of the geotextile is sealed and wrapped in The outer surface of the cement fly ash gravel pile is consolidated into a whole, which isolates the pile material from the surrounding soil, provides a great radial constraint force for the pile, and improves the rigidity of the pile.

Referring to Fig. 3, the outer sleeve 12 of the geogrid has functions of filtering, drainage, reinforcement and corrosion resistance, and the surface of the material is rough. And the selection of materials is flexible. When the damage of the CFG pile mainly occurs at the pile head, the outer sleeve 12 of the geogrid can extend 3-4 times the pile diameter downwards from the pile top of the drilled and pressure-grown plain concrete pile 10. When the pile is stable When the underlying layer is buried deeply, the outer sleeve 12 of the geogrid needs to extend downwards to the bottom of the pile.

When CFG strengthens the flow-plastic layer, especially the inclined flow-plastic layer, when it is subjected to dynamic loads (such as the impact of the piles that are pouring sinking tubes around the piles on the piles that have been constructed, the load of roadbed vehicles, earthquake loads, etc.), it will cause soft soil The super static pore water pressure is generated, and the pile body is also very easy to suffer from the shear force given to it by the soil and the pile will break. The utility model wraps the geotextile inner sleeve 11 and the geogrid outer sleeve 12 outside the drilled pressure grouting plain concrete pile 10, and the pore water can be discharged in time along the geogrid outer sleeve 12, which can greatly improve the drilling efficiency. The shear strength of the pressure poured plain concrete pile 10. In the deep soft soil layer, due to the low bearing capacity, high compressibility and high water content of the soil, it is often necessary to drive the pile to a deeper soil layer, and the CFG pile often breaks due to its low shear strength, and the pile length is usually It can only be designed to be 10-15m. Under the radial constraints of the geotextile inner sleeve 11 and the geogrid outer sleeve 12, the stiffness of the pile body is greatly improved, and the pile length can be designed to be longer. In this way, the side friction resistance and end bearing capacity of the pile are improved, and the deformation can be effectively reduced, which greatly expands the application range of CFG piles. In addition, the inner sleeve 11 of the geotextile can avoid pile quality problems such as necking and pile body inclusion caused by silt filling in during the pile forming process, and water ingress during pile sinking, and prevent damage to the pile body caused by surrounding corrosive substances. erosion, improving the durability of the pile. The outer surface of the geogrid outer sleeve 12 is rough, which is conducive to the exertion of side friction resistance. The pore water can be discharged upward along the gap between the geotextile inner sleeve 11 and the geogrid outer sleeve 12, which is beneficial to the earthquake load. Dissipation of pore water pressure.

Referring to FIG. 2 , the mattress layer is composed of a lower mattress layer 22 , a geogrid layer 23 and an upper mattress layer 21 laid in sequence. The geogrid layer 23 has the function of drainage isolation, blocking the water on the upper part of the foundation, cutting off the groundwater and introducing it into the side ditch. The geogrid layer 23 can reinforce the foundation horizontally to reduce differential settlement. Usually, the lower mattress layer 22 and the upper mattress layer 21 are paved with graded sandstone, with a thickness of 5-15 cm. Because the cushion material is a high damping material, it exhibits strong damping and energy dissipation characteristics. When a large vibration occurs, the cushion material can enter the elastic-plastic or plastic state earlier, which reduces the stiffness of the system and lengthens the cycle. This has an obvious effect on avoiding resonance, or reducing the amplitude of resonance, so it can isolate part of the earthquake action. At the same time, the cushion layer can also isolate part of the vehicle load of the subgrade, and reduce the impact of upper vibration on the fluid plastic soil and pile foundation.

Referring to Fig. 4 and Fig. 5, when the soft soil is disturbed, ultra-static pore water pressure is generated, the pore water passes through the outer sleeve 12 of the geogrid, while the plastic-like soil is intercepted, and the pore water is released by the inner sleeve of the geotextile. 11. The gap between the outer sleeve 12 of the geogrid seeps upward until the lower mattress layer 22, and then the lower mattress layer 22 and the geogrid layer 23 are introduced into the drainage ditch around the foundation to be discharged, and the geogrid layer 23 has the effect of drainage isolation, prevents groundwater from infiltrating upwards, and simultaneously blocks and introduces the water soaked from the foundation 30 and the upper cushion layer 21 into the side ditch.

With reference to Fig. 1, flow plastic shape soft ground reinforcement structure of the present utility model is constructed according to the following steps:

① Drill the pile hole to the design depth;

② Lower the protective sleeve into the pile hole, place the bonded geotextile inner sleeve 11 and geogrid outer sleeve 12 in the sleeve, the inner diameter of the sleeve and the geotextile inner sleeve 11, the geogrid outer sleeve 12 The external diameter of the combination matches the diameter of the pile;

③Pump the drilled concrete pile 10 mixture into the casing;

④Clear the protective soil layer between the piles and the design elevation from the pile head to the top of the pile for 10 bored pressure-grown plain concrete piles;

⑤Construction mattress. The lower mattress layer 22, the geogrid layer 23, and the upper mattress layer 21 are successively paved. The overlapping length of the adjacent grids in the geogrid layer 23 is 30 cm, which is fixed by iron wire binding, and the grid is at the edge of the foundation. The width of the pavement is 2.5m ~ 3m. After the upper mattress layer 21 is paved, it is folded back. The lower mattress layer 22 and the upper mattress layer 21 are laid with graded sand and gravel, the thickness is 5-15cm, and the particle size of the gravel is preferably 8-20mm, the volume ratio of gravel and sand is 1:2. The lower cushion layer 22 and the upper mattress layer 21 are laid empty first, and then compacted to the design thickness by static force or dynamic force after completion, and the degree of compaction generally shall not be greater than 0.90. For relatively dry sand and gravel materials, it can be properly sprinkled with water after laying, and then rolled or tamped.

The above are just some principles of a flow-plastic soft soil foundation reinforcement structure of the utility model with illustrations, and are not intended to limit the utility model to the specific structure and scope of application shown and described, so all possible The corresponding modifications and equivalents used all belong to the patent scope of the utility model application.

Claims (3)

1. a stream is moulded shape reinforced soft soil ground structure, comprise drilling & grouting piling plain concrete pile (10) longitudinal, that be horizontally arranged at interval in stream is moulded shape Soft Soil Layer, and be layed in the mattress layer of drilling & grouting piling plain concrete pile (10) end face, basis (30) is constructed on mattress layer, it is characterized in that: described drilling & grouting piling plain concrete pile (10) surperficial outer wrapping geotextiles inner sleeve (11), the surperficial outer wrapping bonding geo-grid outer sleeve of geotextiles inner sleeve (11) (12).

2. a kind of stream as claimed in claim 1 is moulded shape reinforced soft soil ground structure, it is characterized in that: described mattress layer is by the lower mattress layer (22) of laying successively, geogrids layer (23) and the compound formation of upper mattress layer (21).

3. a kind of stream as claimed in claim 2 is moulded shape reinforced soft soil ground structure, it is characterized in that: described geotextiles inner sleeve (11) wraps up along drilling & grouting piling plain concrete pile (10) total length, and bottom sealing, described geo-grid outer sleeve (12) by drilling & grouting piling plain concrete pile (10) stake top to downward-extension 3-4 doubly stake footpath or extend downward at the bottom of.

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