Open caisson method foundation structure suitable for shallow water sandy gravel area
By using a combination of sandbag cofferdams and concrete well shafts in shallow sandy and gravel areas, the complex and costly problems of traditional sheet pile cofferdams have been solved. This has resulted in a stable construction environment and economical foundation structure fixation, improving construction efficiency and foundation stability.
Patent Information
- Application Number
- CN202520266858.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-02-19
- Publication Date
- 2026-02-10
- Estimated Expiration
- 2035-02-19
AI Technical Summary
When constructing foundations in shallow sandy and gravelly areas, the traditional steel sheet pile enclosure method involves many procedures and is costly. Furthermore, the sandy and gravelly strata have poor stability, which can easily lead to slope collapse, affecting the construction progress and economy.
Sandbags were used to form a cofferdam to isolate the water source. A concrete well shaft was used in conjunction with the well cutting edge. The foundation structure was fixed by sinking the well shaft and using a concrete cushion layer. Medium and coarse sand was used to backfill and stabilize the foundation, avoiding the use of sheet piles for enclosure, thus reducing construction complexity and cost.
It enables a dry construction environment in shallow water and gravel areas, reduces construction complexity and cost, ensures the stability of the foundation and the fixation of the basic structure, avoids slope collapse, and improves construction efficiency and economy.
Smart Images
Figure CN223893410U_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The utility model relates to the technical field of building construction, especially to a sinking well method foundation structure suitable for shallow sand pebble area. BACKGROUND
[0002] The construction of foundation in shallow sand pebble area often occurs in engineering construction, and the geological condition needs to consider whether water will affect personnel and machinery construction, whether the construction operation surface needs to be kept dry, and the self stability of sand pebble stratum is very poor, and once the sand pebble stratum is excavated without support, the side slope will inevitably collapse. The traditional technology constructs the foundation in shallow sand pebble area by the way of steel sheet pile enclosure, but the method has many procedures, high cost and is not economical. UTILITY MODEL CONTENT
[0003] The utility model aims at the shortage of prior art, provides a sinking well method foundation structure suitable for shallow sand pebble area, including the cofferdam surrounded by sandbags, the ground surrounded by the cofferdam is the tentative construction site, the concrete shaft is made on the tentative construction site, the lower end of the concrete shaft is provided with the well blade foot, the foundation pit is excavated in the concrete shaft on the tentative construction site, the concrete shaft is sunk into the foundation pit through the well blade foot, after the concrete shaft is sunk into the design position, the concrete cushion layer is poured at the bottom of the concrete shaft, the foundation structure is poured above the concrete cushion layer, and the gap between the foundation structure and the well wall of the concrete shaft is backfilled with medium coarse sand.
[0004] Preferably, the concrete shaft is cast in situ by using a formwork support, the width of the concrete shaft is not less than 40cm, the lower opening of the concrete shaft is left with an inclination of 45° as the well blade foot, and the inside of the concrete shaft is provided with the reinforcement main reinforcement.
[0005] Preferably, the reinforcement main reinforcement of the concrete shaft adopts three-level steel with a diameter of not less than 16mm and a spacing of 15cm.
[0006] Preferably, the thickness of the concrete cushion layer is not less than 30cm, and the strength is not less than C30.
[0007] In summary, the utility model has the following beneficial effects: first, sandbags are used to build cofferdams to isolate rivers and streams, and the water in the cofferdams is drained to ensure a dry construction work surface; the setting of the well blade foot facilitates the sinking of the concrete cushion layer by gravity after the earthwork in the well is removed, and reduces the frictional resistance with the soil; when the concrete well shaft reaches the designed position, the concrete well shaft is used to prevent the collapse of the slope, and the construction of the concrete cushion layer in the concrete well shaft separates the foundation structure from the pebble stratum, ensures the firmness of the foundation, and fixes the lateral position of the foundation structure by backfilling medium-coarse sand between the concrete well shaft and the foundation structure, preventing the foundation structure from tilting, so the utility model, compared with the prior art, does not need to use steel sheet piles to enclose, is more convenient to construct, and is also lower in cost. BRIEF DESCRIPTION OF DRAWINGS
[0008] The accompanying drawings are included to provide a further understanding of the utility model, and constitute a part of the specification, and are used together with the embodiments of the utility model to explain the utility model, and do not constitute a limitation on the utility model. In the drawings:
[0009] Figure 1 is the construction plan view of the utility model;
[0010] Figure 2 is Figure 1 is the I-I sectional view of the utility model.
[0011] In the drawings: 1, sandbag; 2, pebble stratum; 3, foundation pit; 4, concrete well shaft; 5, well blade foot; 6, concrete cushion layer; 7, foundation structure; 8, medium-coarse sand. DETAILED DESCRIPTION
[0012] The technical scheme of the utility model will be described in detail below with reference to the drawings, but the protection scope of the utility model is not limited to the described embodiments.
[0013] With reference to Figure 1The utility model relates to a kind of open caisson method foundation structure 7 suitable for shallow sand pebble area, including the cofferdam formed by sandbag 1, the ground of cofferdam city is quasi-construction site, concrete shaft 4 is made on quasi-construction site, the lower end of the concrete shaft 4 is provided with well blade foot 5, base pit 3 is excavated in concrete shaft 4 on quasi-construction site, the concrete shaft 4 is sunk into base pit 3 by well blade foot 5, after concrete shaft 4 sinks into design position, concrete cushion 6 is poured at the bottom of concrete shaft 4, foundation structure 7 is poured above the concrete cushion, the gap between foundation structure 7 and the well wall of concrete shaft 4 is backfilled with medium coarse sand 8, in the utility model, first, sandbag 1 is used to cofferdam, river water is isolated, water in cofferdam is removed, to ensure dry construction working surface, well blade foot 5 is provided to facilitate the removal of earthwork in well, concrete cushion can sink by gravity after earthwork in well is removed, reduce the frictional resistance with soil, when concrete shaft 4 reaches design position, prevent the collapse of side slope by concrete shaft 4, and make foundation structure 7 and pebble stratum 2 isolated by constructing concrete cushion 6 in concrete shaft 4, ensure firm foundation, the transverse position of foundation structure 7 can be fixed by medium coarse sand 8 backfilled between concrete shaft 4 and well wall, prevent foundation structure 7 from tilting, so compared with prior art, without using steel sheet pile enclosure, construction is more convenient, and cost is also lower.
[0014] Preferably, the concrete shaft 4 is cast in situ using a formwork support, the width of the concrete shaft 4 is not less than 40 cm, so that the concrete shaft 4 has good compression resistance, the lower opening of the concrete shaft 4 is left with an inclination of 45° as a well blade foot, the interior of the concrete shaft 4 is provided with a reinforcing main reinforcement, the reinforcing main reinforcement of the concrete shaft 4 uses three-level steel with a diameter of not less than 16 mm and a spacing of 15 cm, to ensure that the well wall body of the concrete shaft 4 has high strength and avoids collapse of the concrete shaft 4.
[0015] Preferably, the thickness of the concrete cushion is not less than 30 cm, and the strength is not less than C30, so that the bottom of the foundation structure 7 is firm, and the foundation structure 7 is firm.
[0016] The construction method of the utility model comprises the following steps:
[0017] 1. Shallow cofferdam construction: because the foundation construction area is located in a shallow water area, sandbags are used to cofferdam, river water is isolated, and water in the cofferdam is removed to ensure a dry construction working surface.
[0018] 2. Site leveling: the site is leveled on the construction site, and the foundation bearing capacity of the concrete shaft 4 is not less than 120 Kpa.
[0019] 3. Concrete shaft 4 production: on the leveled site, a concrete square shaft is produced, using the template support method as the formwork for the cast-in-place concrete. The concrete shaft 4 is not less than 40 cm wide, and the lower opening of the concrete shaft 4 is left with a 45° inclined angle, so that after the earthwork in the shaft is removed, the concrete cushion can sink by gravity, reducing the frictional resistance with the soil. The main reinforcement of the concrete shaft 4 uses three-level steel with a diameter not less than 16 mm and a spacing of 15 cm.
[0020] 4. Earthwork excavation in the shaft: after the concrete shaft is produced on the leveled site, the earthwork excavation in the shaft begins. The earthwork excavation uses a small excavator combined with manual excavation. The earthwork excavation is symmetrical left and right, and must not be excavated eccentrically, so as to prevent the concrete shaft from sinking unevenly due to the lateral pressure of the earthwork, causing the concrete shaft to be inclined. The depth of each layer of earthwork excavation is not greater than 50 cm. After each excavation, the concrete shaft 4 is observed for inclination, and the building deformation is observed once.
[0021] 5. Concrete shaft 4 sinking: after the earthwork in the shaft is removed in layers and symmetrically, the cutting edge of the lower opening of the concrete shaft 4 begins to cut the earthwork by relying on the gravity of the concrete shaft 4 itself, forming a slow sinking. In this way, the concrete shaft 4 sinks 50 cm for each 50 cm deep layer of earthwork excavation, until the concrete shaft 4 sinks to the designed position.
[0022] 6. Bottom sealing concrete pouring: after the concrete shaft sinks to the designed position, the earthwork excavation in the shaft is stopped. The earthwork in the shaft is leveled, and the pouring of the bottom concrete cushion is started, so as to prevent the earthwork in the shaft from rising and deforming, causing the concrete shaft 4 to be inclined. The thickness of the concrete cushion is not less than 30 cm, and the strength is not less than C30.
[0023] 7. Foundation structure 7 construction: after the cushion has a certain bearing capacity, the subsequent structure construction in the shaft begins.
[0024] 8. Medium-coarse sand 8 backfilling: after the structure construction is completed, the medium-coarse sand 8 is used to backfill the gap between the structure and the wall of the concrete shaft 4, keeping the foundation stable.
[0025] As above, although the utility model has been shown and expressed with reference to a specific preferred embodiment, it must not be interpreted as a limitation on the utility model itself, and various changes can be made to the form and details thereof without departing from the spirit and scope of the utility model defined by the appended claims.
Claims
1. A caisson foundation structure suitable for shallow water and gravel areas, characterized in that: The project includes a cofferdam formed by sandbags, the ground enclosed by the cofferdam being the proposed construction site. A concrete well shaft is constructed on the proposed construction site, with a cutting edge at the lower end of the concrete well shaft. A foundation pit is excavated inside the concrete well shaft on the proposed construction site. The concrete well shaft is sunk into the foundation pit through the cutting edge until it reaches the designed position. A concrete cushion layer is poured at the bottom of the concrete well shaft, and a foundation structure is poured on top of the concrete cushion layer. The gap between the foundation structure and the well wall of the concrete well shaft is backfilled with medium-coarse sand.
2. The caisson foundation structure suitable for shallow water and gravel areas according to claim 1, characterized in that: The concrete well cylinder is cast in place using a formwork support. The width of the concrete well cylinder is not less than 40cm. The bottom of the concrete well cylinder has a 45° inclined angle as the well cutting edge. The interior of the concrete well cylinder is equipped with reinforced main bars.
3. A caisson foundation structure suitable for shallow water and gravel areas according to claim 2, characterized in that: The main reinforcement bars of the concrete well shaft are grade III steel with a diameter of not less than 16mm and a spacing of 15cm.
4. A caisson foundation structure suitable for shallow water and gravel areas according to claim 3, characterized in that: The thickness of the concrete cushion layer shall not be less than 30cm and the strength shall not be less than C30.