Double-layer foundation shallow layer curing structure

Abstract

The utility model discloses a double-layer foundation shallow layer solidification structure, and relates to the technical field of foundation treatment. Comprising a foundation pit, the foundation pit further comprises a lower curing layer and an upper curing layer, a bonding interface layer is arranged between the lower curing layer and the upper curing layer, a soft soil layer is arranged at the bottom of the foundation pit, a plurality of piles are embedded in the foundation pit, and the piles are vertically and horizontally arranged and embedded in the soft soil layer. The lower curing layer is located above the soft soil layer, and the upper curing layer is located above the lower curing layer; a synergistic stress system is formed through the double-layer foundation with the high-strength impermeability of the upper curing layer and the flexible bearing of the lower curing layer, the bearing capacity and stability of the foundation are effectively improved, sedimentation is reduced, the utilization rate of waste residues is increased, the material cost is effectively reduced, the structure is more environmentally friendly and saves energy, and the structure is particularly suitable for treatment of soft foundations and has good application prospects. Such unfavorable geological conditions as sludge and mucky soil.

Description

Technical Field

[0001] This utility model relates to the field of foundation treatment technology, and in particular to a shallow solidification structure for a double-layer foundation. Background Technology

[0002] Soft soil generally refers to cohesive soils with high natural water content, high compressibility, low bearing capacity, and very low shear strength, exhibiting a soft plastic or fluid plastic state. Soft soil is a general term for a class of soils, not a specific type. In engineering, soft soil is often subdivided into soft cohesive soil, silty soil, silt, peat soil, and peat, etc. It is characterized by high natural water content, large natural void ratio, high compressibility, low shear strength, small consolidation coefficient, long consolidation time, high sensitivity, high disturbance, poor permeability, complex layered distribution, and significant differences in physical and mechanical properties between layers. The bearing capacity and deformation of soft soil foundations often fail to meet design requirements; therefore, foundation treatment measures are necessary to improve foundation strength and reduce settlement. Currently, commonly used soft soil foundation treatment methods include drainage consolidation, replacement, sand and gravel compaction piles, cement mixing piles, bored cast-in-place piles, precast concrete piles, and pine piles.

[0003] Traditional shallow foundation solidification often uses a single uniform solidification layer, but a single solidification layer is difficult to meet the requirements of compressive strength and impermeability. The solidification layer is prone to cracks due to stress concentration and has poor adaptability to composite soft foundations. Utility Model Content

[0004] The purpose of this invention is to provide a shallow solidification structure for a double-layer foundation, which solves the aforementioned technical problems.

[0005] To achieve the above objectives, this utility model provides the following technical solution: a double-layer foundation shallow solidification structure, including a foundation pit, the foundation pit further including a lower solidification layer and an upper solidification layer, a bonding interface layer is provided between the lower solidification layer and the upper solidification layer, the bottom of the foundation pit is a soft soil layer, a number of piles are pre-embedded inside the foundation pit, the number of piles are arranged longitudinally and transversely and embedded in the soft soil layer, the lower solidification layer is located above the soft soil layer, and the upper solidification layer is located above the lower solidification layer.

[0006] Preferably, the lower curing layer is made of an industrial waste-based flexible curing material, and the upper curing layer is made of a cement-based rigid curing material. The thickness of the upper curing layer is 30-50 cm. The cement-based rigid curing material includes, but is not limited to, cement and fiber, wherein the cement content is 8-12% and the fiber content is 0.3-0.8%. The thickness of the lower curing layer is 50-80 cm. The industrial waste-based flexible curing material includes, but is not limited to, lime, fly ash, and slag, and the mass ratio of lime, fly ash, and slag is 1:(1.5-3):(1-2).

[0007] Preferably, the bonding interface layer is a sawtooth interlocking surface, wherein the tooth height is 3-5 cm, the tooth pitch is 10-15 cm, and the tooth groove inclination angle is 45°-60°.

[0008] Preferably, the bonding interface layer is a bidirectional geogrid, wherein the tensile strength of the bidirectional geogrid in both the longitudinal and latitudinal directions is ≥50kN / m and the elongation is ≤10%.

[0009] Preferably, a gradient transition zone of curing material is formed in the upper 10-15cm range of the lower curing layer, and the cement content gradually increases from 0% to 20-30% of the content of the upper curing layer.

[0010] Preferably, the lower solidified layer is embedded in the top of the pile.

[0011] Compared with related technologies, the shallow solidification structure for a double-layer foundation provided by this utility model has the following beneficial effects:

[0012] This invention provides a double-layer foundation shallow solidification structure. First, a 1.2-meter-deep foundation pit is excavated. Then, piles are driven into the soft soil layer. Next, the lower solidification layer is filled into the foundation pit. After the lower solidification layer reaches the required thickness, a biaxial variable-speed mixing device is used. The mixing speed of the lower solidification layer is reduced by 30-50% compared to the upper solidification layer. The piles are processed before the lower solidification layer initially sets. Then, the upper solidification layer is laid. Through the high-strength impermeability of the upper solidification layer and the flexible bearing capacity of the lower solidification layer, a synergistic force-bearing system is formed, which effectively improves the bearing capacity and stability of the foundation, reduces settlement, increases the utilization rate of waste residue, effectively reduces material costs, and is more environmentally friendly and energy-saving. This structure is particularly suitable for the treatment of soft foundations, such as silt and silty soil, and other adverse geological conditions.

[0013] This utility model provides a double-layer foundation shallow solidification structure. By combining the setting of the interface layer and improving the shear strength of the upper and lower solidification layers with the serrated interlocking surface, it can be formed by pressing with a serrated indentation machine. Attached Figure Description

[0014] Figure 1 This is a schematic cross-sectional view of the foundation pit structure of this utility model;

[0015] Figure 2 This is a schematic diagram of the lower curing layer structure of this utility model.

[0016] In the diagram: 1. Foundation pit, 2. Soft soil layer, 3. Pile column, 4. Lower solidification layer, 5. Bonding interface layer, 6. Upper solidification layer. Detailed Implementation

[0017] Please see Figures 1-2This utility model provides a technical solution, including a foundation pit 1, which further includes a lower solidification layer 4 and an upper solidification layer 6. A bonding interface layer 5 is provided between the lower solidification layer 4 and the upper solidification layer 6. The bottom of the foundation pit 1 is a soft soil layer 2. Several piles 3 are pre-embedded inside the foundation pit 1. The piles 3 are arranged longitudinally and transversely and embedded in the soft soil layer 2. The lower solidification layer 4 is located above the soft soil layer 2, and the upper solidification layer 6 is located above the lower solidification layer 4. The lower solidification layer 4 is made of a flexible solidification material based on industrial waste residue, and the upper solidification layer 6 is made of a rigid solidification material based on cement. The thickness of the upper solidification layer 6 is 30-50cm. The rigid solidification material based on cement residue includes, but is not limited to, cement and fiber, wherein the cement content is 8-12% and the fiber content is 0.3-0.8%. The thickness of the lower solidification layer 4 is 50-80cm. The flexible solidification material based on industrial waste residue includes, but is not limited to, lime, fly ash, and slag. The mass ratio of lime, fly ash, and slag is 1:(1.5-3):(1-2).

[0018] First, a 1.2-meter-deep foundation pit 1 is excavated. Then, piles 3 are driven into the soft soil layer 2. Next, the lower solidification layer 4 is filled into the foundation pit 1. After the lower solidification layer 4 is filled to the required thickness, a biaxial variable speed mixing device is used. The mixing speed of the lower solidification layer 4 is reduced by 30-50% compared to the upper solidification layer 6. The piles 3 are treated before the lower solidification layer 4 initially sets. Then, the upper solidification layer 6 is laid. Through the high strength and impermeability of the upper solidification layer 6 and the flexible bearing capacity of the lower solidification layer 4, a synergistic force system is formed, which effectively improves the bearing capacity and stability of the foundation, reduces settlement, improves the utilization rate of waste residue, effectively reduces material costs, and is more environmentally friendly and energy-saving. Moreover, this structure is particularly suitable for the treatment of soft foundations, such as silt, silty soil and other adverse geological conditions.

[0019] The interface layer 5 is a sawtooth interlocking surface, with a tooth height of 3-5 cm, a tooth pitch of 10-15 cm, and a tooth groove inclination angle of 45°-60°.

[0020] By combining the interface layer 5 and improving the shear strength of the upper curing layer 6 and the lower curing layer 4 with the serrated interlocking surface, it can be formed by pressing with a serrated indentation machine.

[0021] The interface layer 5 is a bidirectional geogrid with a longitudinal and latitudinal tensile strength of ≥50kN / m and an elongation of ≤10%. A gradient transition zone of solidified material is formed in the upper 10-15cm range of the lower solidified layer 4, and the cement content gradually increases from 0% to 20-30% of the content of the upper solidified layer 6.

[0022] The composite process of using a two-way geogrid interface and a gradient transition of curing agent can effectively solve the problem of differential settlement between new and old roadbeds.

[0023] The lower solidification layer 4 is embedded in the top of the pile 3; through the composite reinforcement structure of the lower solidification layer 4 and the pile 3, the composite bearing capacity of the foundation is further improved.

Claims

1. A shallow solidification structure for a double-layer foundation, comprising a foundation pit (1), characterized in that: The foundation pit (1) also includes a lower solidification layer (4) and an upper solidification layer (6). A bonding interface layer (5) is provided between the lower solidification layer (4) and the upper solidification layer (6). The bottom of the foundation pit (1) is a soft soil layer (2). Several piles (3) are pre-embedded inside the foundation pit (1). The piles (3) are arranged in a longitudinal and transverse manner and embedded inside the soft soil layer (2). The lower solidification layer (4) is located above the soft soil layer (2), and the upper solidification layer (6) is located above the lower solidification layer (4).

2. The double-layered ground shallow solidification structure according to claim 1, characterized in that: The lower curing layer (4) is made of industrial waste-based flexible curing material, and the upper curing layer (6) is made of cement-based rigid curing material. The thickness of the upper curing layer (6) is 30-50cm.

3. The double-layered ground surface solidification structure according to claim 2, wherein: The bonding interface layer (5) is a sawtooth interlocking surface, wherein the tooth height is 3-5cm, the tooth spacing is 10-15cm, and the tooth groove inclination angle is 45°-60°.

4. The double-layered ground surface solidification structure according to claim 3, wherein: The bonding interface layer (5) is a bidirectional geogrid, and the tensile strength of the bidirectional geogrid in both the longitudinal and latitudinal directions is ≥50kN / m, and the elongation is ≤10%.

5. The double-layered ground surface solidification structure according to claim 4, wherein: A gradient transition zone of cured material is formed in the upper 10-15cm range of the lower cured layer (4).

6. The double-layered ground surface solidification structure according to claim 5, wherein: The lower solidified layer (4) is embedded in the top of the pile (3).

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