Method for treating special geology by vibration stone column combined with preloading

Abstract

The application discloses a method for treating special geology by vibration stone pile combined with preloading, which comprises the following steps: measuring and positioning on the special geology to release the hole position of the vibration stone pile; providing a hole forming device, a vibration hammer of the hole forming device is clamped on an impact double tube through a clamp, the impact double tube comprises an inner tube and an outer tube, the outer tube is movably sleeved outside the inner tube, and the impact double tube is aligned with the hole position; the vibration hammer is started to insert the lower end of the impact double tube into the clay layer; the inner tube is pulled out of the outer tube, so that the outer tube is arranged in the special geology; a vibrator is used to form a hole in the clay layer through the outer tube and to form a pile foundation by filling; the outer tube is pulled out, and a pile body is formed by filling vibration in the muddy layer and the block stone filling from bottom to top respectively; a stone cushion layer is laid on the special geology; a sand cushion layer is laid on the stone cushion layer; a drain board is arranged on the sand cushion layer and preloading is carried out in stages. The application solves the problem that the traditional foundation treatment method is prone to cause uneven settlement.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of building construction, in particular to a method for treating special geology by vibration stone pile combined with preloading. BACKGROUND

[0002] With the rapid development of economy and the acceleration of urbanization, land resources are increasingly scarce. In order to meet the needs of urban construction, industrial development and port construction, filling water to create land has become an important way to expand land resources. However, the backfilled water area is often filled directly with stone, and the bottom silt forms protrusions or lenses of different sizes in plane and space during the extrusion process. Therefore, the backfilled foundation usually has characteristics such as high water content, high compressibility and low strength. Traditional single foundation treatment methods such as dynamic compaction and replacement method have certain limitations in treating such foundation. Dynamic compaction may cause uneven settlement and vibration of the foundation; replacement method requires a large amount of high-quality filler, which is costly and may have an impact on the environment. SUMMARY

[0003] In order to overcome the defects of the prior art, a method for treating special geology by vibration stone pile combined with preloading is provided to solve the problem that the traditional foundation treatment method is prone to cause uneven settlement.

[0004] To achieve the above-mentioned purpose, a method for treating special geology by vibration stone pile combined with preloading is provided, comprising the following steps:

[0005] Measuring and positioning on the special geology to release the hole position of the vibration stone pile, the special geology including clay layer, silt layer and block stone filling layer from bottom to top;

[0006] Providing a hole forming device, the hole forming device including a pile frame, a vibration hammer and an impact double pipe, the vibration hammer being installed on the pile frame, the vibration hammer being clamped on the impact double pipe by a clamp, the impact double pipe including an inner pipe and an outer pipe, the outer pipe being movably sleeved outside the inner pipe, and the impact double pipe being aligned with the hole position;

[0007] Turning on the vibration hammer to insert the lower end of the impact double pipe into the clay layer;

[0008] Pulling out the inner pipe from the outer pipe so that the outer pipe is set in the special geology;

[0009] Forming a pile foundation by hole vibration and filling vibration of the vibration hammer through the outer pipe in the clay layer;

[0010] Pulling out the outer pipe and filling and vibration forming a pile body in the silt layer and the block stone filling layer from bottom to top, respectively;

[0011] Laying a gravel cushion on the special geology;

[0012] Laying a sand cushion on the gravel cushion;

[0013] Laying a drainage board on the sand cushion and pre-pressing and grading loading.

[0014] Further, in the step of implementing the vibroflotation into the clay layer, comprising:

[0015] a. sinking the vibroflotation into the clay layer at a speed of 1-2 m / min to 30-50 cm below the designed reinforcement depth of the vibroflotation gravel pile;

[0016] b. lifting the vibroflotation to the top position of the clay layer, and the lifting speed of the vibroflotation is 5-6 m / min;

[0017] c. repeating steps a and b one to two times, and stopping the vibroflotation at the bottom of the hole;

[0018] d. cleaning the hole by circulating water.

[0019] Further, the filling material of the vibroflotation gravel pile is any one of gravel, pebble, and slag.

[0020] Further, the maximum particle size of the filling material is less than or equal to 150 mm, the strength of the filling material is not less than 30 MPa, and the clay content of the filling material is not more than 5%.

[0021] Further, the thickness of the gravel cushion is 0.3 mm.

[0022] Further, the thickness of the sand cushion is 30-50 cm.

[0023] The method for treating special geology by vibroflotation gravel pile combined with pre-pressing and loading of the present application effectively improves the bearing capacity of the backfill water area foundation, greatly reduces the settlement amount of the backfill foundation in the later use process, ensures the uniform stress of each part of the building, and guarantees the stability and safety of the building.

[0024] The method for treating special geology by the vibration gravel pile combined with preloading and surcharge of the application can pass through the upper stone and reach the lower soil to form a composite foundation, improving the overall performance of the foundation. The preloading and surcharge can adjust the surcharge height and loading rate according to different geological conditions and engineering requirements, adapting to the foundation treatment under special geological conditions. The vibration gravel pile combined with preloading and surcharge is simple and fast in construction, requiring less mechanical equipment and manpower, and reducing the engineering cost. The method for treating special geology by the vibration gravel pile combined with preloading and surcharge effectively improves the bearing capacity and stability of the foundation, reduces the maintenance and reinforcement cost in the later stage, and saves the engineering cost. BRIEF DESCRIPTION OF DRAWINGS

[0025] Other features, objects, and advantages of the application will become more apparent from the following detailed description of non-limiting embodiments, when read in conjunction with the accompanying drawings:

[0026] Figure 1 is a sectional view of the special geology of the embodiment of the application.

[0027] Figure 2 is a sectional view of the preloading and surcharge of the embodiment of the application.

[0028] Figure 3 is a pile layout schematic diagram of the vibration gravel pile of the embodiment of the application.

[0029] Figure 4 is a step flowchart of the method for treating special geology by the vibration gravel pile combined with preloading and surcharge of the embodiment of the application. DETAILED DESCRIPTION

[0030] The application will be further described in detail below with reference to the drawings and embodiments. It can be understood that the specific embodiments described herein are only used to explain the related application, but not to limit the application. In addition, it should be noted that only the parts related to the application are shown in the drawings for convenience of description.

[0031] It should be noted that the embodiments in the application and the features in the embodiments can be combined with each other without conflict. The application will be described in detail below with reference to the drawings and embodiments.

[0032] REFERENCE Figures 1 to 4 The application provides a method for treating special geology by vibration gravel pile combined with preloading and surcharge, comprising the following steps:

[0033] S1, measuring and positioning on the special geology to release the hole position of the vibration gravel pile 1, the special geology including clay layer a, silt layer b and block stone fill layer c from bottom to top.

[0034] In this embodiment, the special geology is an artificial island formed by land reclamation, and the sea sediment layer is directly backfilled to form land without treatment. The backfill material is mainly block and broken stone, which is angular, with a particle size of 20mm-400mm, and a small part with a particle size greater than 400mm, and the structure is loose to slightly dense. The area is more than 1km away from the land reclamation boundary and far from the sea, and has the characteristics of high water content, large void ratio, large compressibility and low bearing capacity.

[0035] Referring to Figure 3 As shown in the figure, the land reclamation foundation is treated by using vibration stone pile combined with preloading and surcharge. The vibration stone piles are arranged in a plum blossom shape, with a pile spacing of 2.5m, a pile diameter of 1.2m, and a length of 25m.

[0036] Before the hole is formed, the hole is detected and laid out in a 10x10m square grid. After the survey is completed, the results are recorded, and a columnar graph of the detection hole is drawn to indicate the thickness of each area of the overburden layer and the thickness of the silt.

[0037] Before construction, the construction site is cleaned and leveled to ensure that the site meets the construction requirements. The pile position is arranged according to the design pile arrangement form, spacing and maintenance structure range, and a plan layout is drawn to number each pile. At the same time, the construction machinery and equipment are maintained and maintained to ensure that they meet the use requirements. According to the design parameters of the vibration stone pile and the preloading and surcharge, the required materials are calculated to determine the specifications and usage quantity of the fillers, and the procurement and storage are carried out according to the requirements.

[0038] S2, provide a hole forming device, the hole forming device includes a pile frame, a vibration hammer 2 and an impact double tube 3, the vibration hammer 2 is installed on the pile frame, the vibration hammer 2 is clamped on the impact double tube 3 through a clamp, the impact double tube 3 includes an inner tube and an outer tube, the outer tube is movably sleeved outside the inner tube, and the impact double tube 3 is aligned with the hole position.

[0039] After measuring and positioning, according to the control pile and the design drawing, the vibration hammer is installed on the pile frame after the vibration stone pile hole position is laid out. The impact double tube is aligned with the pile position.

[0040] S3, turn on the vibration hammer 2 to insert the lower end of the impact double tube 3 into the clay layer a.

[0041] Specifically, the position and perpendicularity of the pile frame are adjusted to ensure that the pile position plane error is not greater than 50mm, and the perpendicularity error is not greater than 1%. Turn on the vibration hammer, and through the vibration impact action, make the impact double tube pass through the block and broken stone layer and the silt layer, and reach the underlying clay layer.

[0042] S4, pull the inner tube out of the outer tube, so that the outer tube is set in the special geology.

[0043] The vibrating hammer stops vibrating, the clamp is loosened, the clamp position is adjusted so that the clamp clamps the inner tube. The vibrating hammer is lifted, the inner tube is pulled out of the outer tube, and the outer tube remains in the hole to protect the wall, the crushed stone layer and the silt layer. After pulling out the inner tube, the inner tube is kept on the pile frame, the pile frame is moved away from the construction hole, and waits for the next step of construction.

[0044] S5, the pile foundation is formed by vibrating and flushing the hole in the clay layer a through the outer tube by the vibrator 4 and filling the material.

[0045] As a preferred embodiment, when the step of vibrating and flushing the hole in the clay layer a is implemented, it includes:

[0046] a. The vibrator 4 is sunk in the clay layer a at a speed of 1-2 m / min to a position 30-50 cm below the designed reinforcement depth of the vibrating crushed stone pile 1;

[0047] b. The vibrator 4 is lifted to the top position of the clay layer at a lifting speed of 5-6 m / min;

[0048] c. Steps a and b are repeated one to two times, and the vibrator 4 is stopped at the bottom of the hole;

[0049] d. The hole is cleaned by circulating water.

[0050] Specifically, in the clay layer, the 180kW vibrator is lifted by the crawler crane to the top of the clay layer, the position of the vibrator is adjusted to ensure that the planar error of the pile position is not greater than 50mm. The hoist of the crane is started, and the vibrator is slowly sunk in the clay layer at a speed of 1-2 m / min until it reaches a position 30-50 cm below the designed reinforcement depth. At this time, the vibrator is lifted to the top of the clay layer, and the lifting speed can be increased to 5-6 m / min. The above steps are repeated one to two times, and finally the vibrator is stopped at a position 30-50 cm above the designed reinforcement depth. The mud in the hole is thinned by circulating water to complete the hole cleaning.

[0051] The impact hole diameter is 500-800mm, and the hole verticality deviation is not greater than 1%.

[0052] After the vibrator is installed, length marks should be made on the equipment, 0.5m for a section, so that the operator can control the depth of the vibrator into the soil according to the marks.

[0053] When the pile is formed by vibroflotation in the clay layer, the filler is poured into the hole, and the vibroflotation device is sunk into the filler for compaction. At this time, the current value of the vibroflotation device rapidly increases, and when the compaction current reaches a specified value, it is considered that the pile body at this depth has been compacted. If the compaction current does not reach the specified value, the vibroflotation device needs to be lifted to continue to fill the hole with the filler, and then the vibroflotation device is sunk again to continue compaction. This repeated operation is continued until the compaction current at this depth reaches the specified value. After the completion of a section of the gravel pile, the vibroflotation device is lifted for the construction of the next section of the gravel pile, and the compaction is sequentially added in sections upward until the top surface of the clay layer, and the construction of the gravel pile in the clay layer is completed.

[0054] The depth of the vibroflotation hole in the clay layer should be higher than the design treatment depth by 0.3-0.5 m to prevent the high-pressure water from disturbing the foundation soil below the design treatment depth.

[0055] S6, the outer tube is pulled out, and the pile body is formed by filling the filler in the silt layer b and the block gravel filling from bottom to top.

[0056] Specifically, when the outer tube is pulled out, the pile frame and the vibration hammer used to pull the inner tube are moved to the construction hole position, the inner tube is hoisted on the top of the pile frame and kept stationary by using the auxiliary winch. The vibration hammer is lowered to the hole opening, the clamp on the vibration hammer clamps the outer tube, the vibration hammer is lifted, and the outer tube is vibrated and pulled out. As the outer tube is gradually pulled out, the inner and outer tubes are recombined together. The position of the clamp on the vibration hammer is adjusted so that the clamp clamps the inner and outer tubes at the same time, and the pile frame is moved to the next construction point for impact hole formation construction.

[0057] When the pile is formed by vibroflotation in the silt layer, after the vibration hammer is removed, the 180 kW vibroflotation device is hoisted by the crawler crane to the top of the backfilled gravel in the hole, the position of the vibroflotation device is adjusted to ensure that the planar error of the pile position is not greater than 50 mm. The winch of the crane is started, and the vibroflotation device is slowly sunk in the soil at a speed of 1-2 m / min until the bottom of the silt layer is reached;

[0058] When the pile is formed by vibroflotation in the block gravel layer, the vibroflotation device continues to be lifted to the bottom of the gravel layer. The filler is poured into the hole, and the vibroflotation device is sunk into the filler for compaction. After the completion of a section of the gravel pile, the vibroflotation device is lifted for the construction of the next section of the gravel pile, and the compaction is sequentially added in sections upward until the design elevation of the pile top, and the construction of the gravel pile in the block gravel layer is completed.

[0059] As a preferred embodiment, the filler of the vibration gravel pile 1 material is any one of gravel, pebble, and slag.

[0060] The maximum particle size of the filler is less than or equal to 150 mm, the strength of the filler is not less than 30 MPa, and the silt content of the filler is not greater than 5%.

[0061] The filler should be well-graded, with a maximum particle size of ≤20 cm, a natural compressive strength of ≥30 MPa, a softening coefficient of ≥0.75, and a silt content of ≤10%, and should not use silt, cultivated soil, frozen soil, expansive soil, and soil with an organic matter content of more than 5%.

[0062] As a preferred embodiment, gravel is filled and compacted at a depth of about 1 m from the ground surface to ensure the compactness of the pile top.

[0063] S7, laying a gravel cushion 5 on special geology.

[0064] A gravel cushion is provided on the pile top, with a thickness of 0.3 m, and is laid with well-graded gravel. After laying, the cushion is vibrated and rolled to be flat.

[0065] S8, laying a sand cushion on the gravel cushion 5.

[0066] Before laying the sand cushion, quality detection procedures such as foundation strength or foundation bearing capacity inspection are carried out.

[0067] A layer of sand cushion is laid on the ground surface, with a thickness of generally 30-50 cm.

[0068] After laying the sand cushion, drainage boards are set up, with a width of 100-400 mm and a thickness of 3-8 mm.

[0069] Monitoring points are set up in the area of preloading, including settlement observation points, pore water pressure observation points, and horizontal displacement observation points, to ensure that the deformation and consolidation of the foundation can be accurately monitored.

[0070] According to the design requirements, the loading is carried out in stages, and the height and loading rate of each stage are strictly controlled.

[0071] During the preloading process, the monitoring points are observed regularly, and data such as the settlement, pore water pressure, and horizontal displacement of the foundation are recorded. According to the monitoring results, the loading height and loading rate are adjusted in time to ensure the stability and safety of the foundation.

[0072] Each layer of filling has a thickness of not more than 500 mm, and the surface adjacent height difference is not more than 200 mm.

[0073] When the settlement rate of the foundation is less than the design requirement for several days in a row, or the degree of consolidation of the foundation reaches the design requirement, the loading is carried out in stages.

[0074] The site surface is cleared of debris and obstacles using a bulldozer, and the site is initially leveled; a roller is used for rolling work to compact the site; the rolling work follows the principle of from the edge to the center and from low to high, ensuring that the site is uniformly and densely compacted.

[0075] After the reinforcement is completed, the static load test method is used to detect the bearing capacity of the reinforced area of the foundation.

[0076] The method for treating special geology by vibration gravel pile combined with preloading by stacking can effectively improve the bearing capacity of the backfill water area foundation, greatly reduce the settlement of the backfill foundation in the later use process, ensure the uniform stress of each part of the building, and ensure the stability and safety of the building.

[0077] The method for treating special geology by vibration gravel pile combined with preloading by stacking can effectively improve the bearing capacity of the backfill water area foundation, greatly reduce the settlement of the backfill foundation in the later use process, ensure the uniform stress of each part of the building, and ensure the stability and safety of the building.

[0078] The above description is only the preferred embodiment of the application and the explanation of the applied technical principles. Those skilled in the art should understand that the scope of the application involved in the present application is not limited to the technical solutions formed by the specific combination of the above technical features, and should also cover other technical solutions formed by any combination of the above technical features or their equivalent features without departing from the inventive concept. For example, the technical solutions formed by replacing the above features with the technical features disclosed in the present application (but not limited to) having similar functions.

Claims

1. A method for treating special geological conditions using a combination of vibratory crushed stone piles and surcharge preloading, characterized in that, Includes the following steps: The location of the vibratory stone pile hole is determined by measuring and positioning on special geological conditions, which include, from bottom to top, a clay layer, a silt layer, and a block stone fill layer. A hole-forming device is provided, comprising a pile frame, a vibratory hammer, and an impact double tube. The vibratory hammer is mounted on the pile frame and is clamped to the impact double tube by a clamp. The impact double tube includes an inner tube and an outer tube, with the outer tube movably sleeved outside the inner tube to align the impact double tube with the hole position. Turn on the vibratory hammer and insert the lower end of the impact double tube into the clay layer; The inner tube is pulled out from the outer tube, so that the outer tube is installed in the special geological conditions; the outer tube remains inside the hole to protect the wall, and the hole is completed in the layer of gravel and silt. Piles are formed by vibratory compaction through the outer pipe of a vibratory compactor to create holes in the clay layer and filling the soil. Remove the outer pipe and vibrate the filler material from bottom to top in the silty layer and the crushed stone filling to form the pile body; A crushed stone cushion layer is laid on the aforementioned special geological surface; A sand cushion layer is laid on the crushed stone cushion layer; Drainage boards are installed on the sand cushion layer and pre-loading and grading are carried out.

2. The method for treating special geological conditions using vibratory crushed stone piles combined with surcharge preloading according to claim 1, characterized in that, The step of vibratory drilling in the clay layer includes: a. The vibratory compactor is driven into the clay layer at a speed of 1~2m / min to a depth of 30~50cm below the designed reinforcement depth of the vibratory crushed stone pile; b. Raise the vibratory compactor to the top of the clay layer at a lifting rate of 5-6 m / min. c. Repeat steps a and b once or twice, and keep the vibratory impactor at the bottom of the hole; d. Clean the holes using circulating water.

3. The method for treating special geological conditions using vibratory crushed stone piles combined with surcharge preloading according to claim 2, characterized in that, The filler material of the vibratory crushed stone pile can be any one of crushed stone, pebbles, or slag.

4. The method for treating special geological conditions using vibratory crushed stone piles combined with surcharge preloading according to claim 3, characterized in that, The maximum particle size of the filler is less than or equal to 150 mm, the strength of the filler is not less than 30 MPa, and the mud content of the filler is not greater than 5%.

5. The method for treating special geological conditions using vibratory crushed stone piles combined with surcharge preloading according to claim 1, characterized in that, The thickness of the crushed stone cushion layer is 0.3 mm.

6. The method for treating special geological conditions using vibratory crushed stone piles combined with surcharge preloading according to claim 1, characterized in that, The thickness of the sand cushion layer is 30~50cm.

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