Foundation reinforcing method

Abstract

The invention discloses a foundation reinforcing method which comprises the following steps: S1, pine pile manufacturing and preservative treatment; s2, a foundation pit is excavated; s3, lofting is conducted according to the pile position of the plum blossom pile, and a reserved hole is drilled; s4, the excavator is in place; s5, the timber piles are hoisted and vertically inserted into the preformed holes; s6, pile pressing construction is conducted; s7, the pile head is sawed flat; s8, gravel is filled between the piles and tamped; s9, a reinforcement cage is laid on the compacted gravel, and the reinforcement cage and the pine piles are bound together; and S10, after the reinforcement cage is bundled, concrete is poured into the foundation pit, and the reinforcement cage is covered. According to the method, the purpose of improving the bearing capacity of the foundation is achieved by adopting the pine pile composite foundation, the pine pile composite foundation has the advantages of being convenient to construct, short in construction period, low in engineering cost and free of environmental protection risks aiming at the complex foundation with the soft soil thickness smaller than 7 m, meanwhile, a large amount of earth excavation can be avoided, and the construction cost is reduced. The raw materials are low in price and easy to purchase.

Description

Technical Field

[0001] The present invention relates to the technical field of foundation reinforcement, and in particular to a foundation reinforcement method. Background Art

[0002] Soft foundation is a kind of bad foundation. According to the cause, it can be generally divided into artificial fill foundation; silt clay foundation formed by marine, river and lake phases; clay foundation with pebbles and boulders formed by various piedmont alluvial and flood phases, etc. Since soft soil has the characteristics of low strength, high compressibility and low permeability, it is necessary to pay attention to the deformation and stability of the foundation when building on soft soil foundation. Buildings on soft soil foundation often have the problem that the foundation strength and deformation cannot meet the design requirements, so measures are often needed to treat the foundation. The purpose of treatment is to improve the strength of soft foundation, ensure the stability of the foundation, reduce the compressibility of soft soil, and reduce the settlement and uneven settlement of the foundation. In the past, the commonly used foundation treatment methods were replacement cushion method, pile foundation method, deep mixing method or preloading method. Although the above methods can effectively treat bad foundations, they have the characteristics of long construction period, high engineering cost and prominent environmental protection problems. Therefore, for some building foundations with fewer floors and lighter loads, or in the case of local dark ponds, and complex foundations with soft soil thickness less than 7m, it is necessary to adopt a treatment method that is convenient to construct, has a short construction period, low engineering costs, and no environmental risks. Summary of the invention

[0003] The purpose of the present invention is to solve the shortcomings of the prior art and to propose a foundation reinforcement method.

[0004] In order to achieve the above object, the present invention adopts the following technical solution: a foundation reinforcement method, comprising the following steps: S1: Production and anti-corrosion treatment of pine wood piles; S2: excavation of foundation pit; S3: Lay out the positions of the plum blossom piles and drill reserved holes; S4: Excavator is in place; S5: The wooden pile is lifted and vertically inserted into the reserved hole; S6: pile driving construction; S7: sawing the pile head flat; S8: Fill the space between piles with crushed stones and compact them; S9: Lay the steel cage on the compacted gravel and tie the steel cage to the pine piles; S10: After tying the steel cage, pour concrete into the foundation pit and cover the steel cage.

[0005] As a further description of the above technical solution: In step S1, fresh pine wood with a diameter of 10cm-15cm is used for making pine wood piles. The bark is removed and the material is checked. The shape should be straight, smooth and round without defects and bends. The thin end of the pine wood is cut into a 30cm long pointed end, and the thick end of the pine wood is sawn flat and tied with wire.

[0006] As a further description of the above technical solution: The antiseptic treatment in step S1 is to paint the pine wood pile body with tung oil.

[0007] As a further description of the above technical solution: The excavation of the foundation pit in step S2 refers to digging a foundation pit on a soft soil foundation.

[0008] As a further description of the above technical solution: The stakeout of the plum blossom piles in step S3 is performed according to the size of the bottom of the foundation pit, and the pile positions are arranged in a plum blossom shape. The number of piles per square meter is calculated according to the cross-sectional area of ​​a single pile, the bearing capacity of the foundation, the natural porosity of the soil before compaction, and the porosity required to be achieved after the soil is compacted.

[0009] As a further description of the above technical solution: In step S4, the excavator is in place means that the excavator enters the foundation pit.

[0010] As a further description of the above technical solution: The hoisting of the wood pile in step S5 refers to using a crane to vertically hoist the pine wood pile, and straightening the pine wood pile so that the tip of the pine wood pile is aligned with the reserved hole.

[0011] As a further description of the above technical solution: The pile pressure construction in step S6 refers to using the bucket of an excavator to press the pine piles into the soil base and into the bearing layer.

[0012] As a further description of the above technical solution: Said step S7 of sawing the pile head flat refers to controlling the sawing of the pile head flat according to the pile top elevation so that each pile top is kept in the same plane, and said pile top elevation refers to the distance from the pile top to the bottom of the foundation pit being greater than or equal to 0.5m.

[0013] As a further description of the above technical solution: The step S8 of filling gravel between piles and compacting it means filling the part between piles with gravel, with a thickness of not less than 0.2m, and compacting it with a tamping machine, which can compact the soil between piles, improve the bearing capacity of the foundation soil between piles, and reduce settlement.

[0014] As a further description of the above technical solution: The step S9 is to lay a steel cage on the compacted gravel and to tie the steel cage to the pine piles, which means that the steel bars are arranged at a spacing of 150-200 mm, are effectively tied to the piles, and the height of the steel cage is 0.3 m.

[0015] The present invention has the following beneficial effects: Compared with the prior art, this foundation reinforcement method achieves the purpose of improving the bearing capacity of the foundation by adopting a pine pile composite foundation. The method of the present invention is aimed at complex foundations with soft soil thickness less than 7m. The pine pile composite foundation has many advantages such as convenient construction, short construction period, low engineering cost, and no environmental risk. At the same time, it can avoid a large amount of earth excavation, and the raw materials are cheap and easy to purchase. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 A schematic diagram of pile pressing of a foundation reinforcement method proposed by the present invention; Figure 2 This is a cross-sectional view of a soft soil foundation treated with pine piles according to a foundation reinforcement method proposed in the present invention. DETAILED DESCRIPTION

[0017] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0018] Reference Figure 1-2 The present invention provides a foundation reinforcement method, comprising the following steps: S1: Production and anti-corrosion treatment of pine wood piles; S2: excavation of foundation pit; S3: Lay out the positions of the plum blossom piles and drill reserved holes; S4: Excavator is in place; S5: The wooden pile is lifted and vertically inserted into the reserved hole; S6: pile driving construction; S7: sawing the pile head flat; S8: Fill the space between piles with crushed stones and compact them; S9: Lay the steel cage on the compacted gravel and tie the steel cage to the pine piles; S10: After tying the steel cage, pour concrete into the foundation pit and cover the steel cage.

[0019] Pine piles are generally made from fresh pine wood with a pile diameter of 10cm-15cm. The bark is removed to check the material. The appearance should be straight, smooth and round without any defects or excessive bends. The small end is cut into a 30cm long pointed tip to facilitate driving into the bearing layer. The top of the pile must be sawn flat first, and the pile head should be tightened with wire. Pine wood is rich in rosin, which can effectively prevent groundwater and bacteria from corroding it. Pine piles are suitable for underwater work and are extremely effective in soft soil foundations in a saturated state. Pine piles generally do not need to be treated with anti-corrosion, but if they are treated with anti-corrosion, double protection can be achieved and the durability of pine piles can be improved, especially when the groundwater is highly corrosive or the soil moisture content is not high. The anti-corrosion treatment of pine piles is crucial. The anti-corrosion treatment of pine piles is to use tung oil to brush the pile body for anti-corrosion treatment after the pine piles are made and formed. Before brushing tung oil, the surface of the pine piles needs to be clean and dry, and there should be no grease or dust wrapped around the pile body. Then apply the first coat of tung oil, and apply the second coat of tung oil after drying. After the second coat of tung oil is dried, clean the pile body with cotton cloth. If the hand feel and gloss do not meet the requirements, you can apply the third coat. The excavation of foundation pit is to carry out the excavation of foundation pit according to the position of foundation plane and the elevation of foundation pit bottom; the stakeout according to the plum blossom pile position and the drilling of reserved holes are carried out, which is carried out according to the size of the base, and the pile positions are arranged in a plum blossom shape. The number of piles per square meter is calculated according to the cross-sectional area of ​​a single pile, the bearing capacity of the foundation, the natural porosity ratio of the soil before compaction and the porosity ratio required to be achieved after the soil is compacted. When there is a hard shell layer at the end of the pile, it can be used as an end-bearing pile; the excavator is in place, which means that an excavator of no less than 260 type is used to enter the foundation pit. The body weight of the 260 type excavator is 26T, and the axial pressure of a single bucket is about 6-8T. If the pile is pressed to 1.5m away from the bottom of the foundation pit, the axial pressure can be increased by the weight of the body itself, which can be increased to about 12T at most; the lifting of the pile and its vertical insertion into the reserved hole means that the pine pile is lifted vertically by a crane, and the pine pile is straightened so that the pile tip is aligned with the reserved hole, so that It is convenient to insert the pine wood pile into the reserved hole to facilitate subsequent construction; pile driving construction refers to turning the bucket of the excavator upside down and pressing the pile into the soil base to the bearing layer. For pine wood piles that are difficult to press into the soil layer in some parts, the back of the bucket can be used to hit the pile head to drive it into the bearing layer. When the top surface of the pile is 1.5m away from the base surface, the weight of the machine body can be used to increase the axial pressure of the single bucket, or the back of the bucket can be used to hit the pile head until there is no obvious amount of hitting, to ensure that the pine wood pile is vertically driven into the bearing layer; sawing flat the pile head, crushing stone between piles and compacting the crushed stone refers to controlling the elevation after sawing flat the pile head according to the elevation of the pile top. Generally, the pile top elevation is required to be about 0.5m higher than the bottom of the foundation pit. Fill with crushed stone and tamp it with a thickness of not less than 0.2m. Then lay the steel cage on the compacted crushed stone, and tie the steel cage to the pine wood pile. After tying the steel cage, pour concrete so that the concrete pouring volume exceeds the top of the steel cage by 5cm.

[0020] Working principle: During construction, first determine the thickness of the soft soil layer and the various indicators of the original soil according to the investigation report, and calculate the spacing and number of piles in combination with the bearing requirements of the proposed building. The diameter of the pine piles should be φ10-15cm fresh pine wood, with a straight and round appearance, and the small end should be cut into a 30cm long pointed head to facilitate driving into the bearing layer; first carry out trial pile construction to determine the pile length; when driving piles, it is necessary to straighten the pine piles, turn the excavator bucket upside down to buckle the piles, and after the pressure is stable, hit the pile head with the back of the bucket until there is no obvious amount of driving, to ensure that the pine piles are driven vertically into the bearing layer; the order of driving piles is from the inside to the outside or from one end to the other to avoid the pile group effect, and then lay the steel cage to connect the steel cage to the pine piles. After laying the steel cage, pour concrete. The reinforced soft soil foundation will make the foundation bearing capacity of the soft soil foundation reach 150KPa and above, meeting the load requirements of the upper structure.

[0021] Finally, it should be noted that the above are only preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments, or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A foundation reinforcement method, characterized in that: The following steps are included: S1: Production and anti-corrosion treatment of pine wood piles; S2: excavation of foundation pit; S3: Lay out the positions of the plum blossom piles and drill reserved holes; S4: Excavator is in place; S5: The wooden pile is lifted and vertically inserted into the reserved hole; S6: pile driving construction; S7: sawing the pile head flat; S8: Fill the space between piles with crushed stones and compact them; S9: Lay the steel cage on the compacted gravel and tie the steel cage to the pine piles; S10: After tying the steel cage, pour concrete into the foundation pit and cover the steel cage.

2. A foundation reinforcement method according to claim 1, characterized in that: In step S1, fresh pine wood with a diameter of 10cm-15cm is used for making pine wood piles. The bark is removed and the material is checked. The shape should be straight, smooth and round without defects and bends. The thin end of the pine wood is cut into a 30cm long pointed end, and the thick end of the pine wood is sawn flat and tied with wire.

3. A foundation reinforcement method according to claim 1, characterized in that: The antiseptic treatment in step S1 is to paint the pine wood pile body with tung oil.

4. A foundation reinforcement method according to claim 1, characterized in that: The excavation of the foundation pit in step S2 refers to digging a foundation pit on a soft soil foundation.

5. A foundation reinforcement method according to claim 1, characterized in that: The stakeout of the plum blossom piles in step S3 is performed according to the size of the bottom of the foundation pit, and the pile positions are arranged in a plum blossom shape. The number of piles per square meter is calculated according to the cross-sectional area of ​​a single pile, the bearing capacity of the foundation, the natural porosity of the soil before compaction, and the porosity required to be achieved after the soil is compacted.

6. A foundation reinforcement method according to claim 1, characterized in that: In step S4, the excavator is in place means that the excavator enters the foundation pit.

7. A foundation reinforcement method according to claim 1, characterized in that: The hoisting of the wood pile in step S5 refers to using a crane to vertically hoist the pine wood pile, and straightening the pine wood pile so that the tip of the pine wood pile is aligned with the reserved hole.

8. A foundation reinforcement method according to claim 1, characterized in that: The pile pressure construction in step S6 refers to using the bucket of an excavator to press the pine piles into the soil base and into the bearing layer.

9. A foundation reinforcement method according to claim 1, characterized in that: Said step S7 of sawing the pile head flat refers to controlling the sawing of the pile head flat according to the pile top elevation so that each pile top is kept in the same plane, and said pile top elevation refers to the distance from the pile top to the bottom of the foundation pit being greater than or equal to 0.5m.

10. A foundation reinforcement method according to claim 1, characterized in that: The step S8 of filling gravel between piles and compacting it means filling the part between piles with gravel, with a thickness of not less than 0.2m, and compacting it with a tamping machine, which can compact the soil between piles, improve the bearing capacity of the foundation soil between piles, and reduce settlement.

11. A foundation reinforcement method according to claim 1, characterized in that: The step S9 of laying the steel cage on the compacted gravel and tying the steel cage to the pine piles means that the steel bars are arranged at a spacing of 150-200 mm, effectively tied to the piles, and the height of the steel cage is 0.3 m.

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