Construction method of super-long precast pile vibration sinking pipe pulling pile

Abstract

The present application relates to the field of building construction technology, especially to the construction method of the super-long precast pile vibration sinking pipe pulling pile, comprising positioning the pile position, determining the pile head position, placing the steel column, backfilling the pile, driving the high-frequency vibration hammer through the hydraulic system, generating the vertical vibration wave transmission to the pile body, making the soil around the pile liquefy or loosen, greatly reducing the friction resistance between the pile and the soil, and simultaneously assisting the high-pressure water jet, impacting the side of the pile and soil, destroying the side friction resistance of the pile, so as to realize the rapid pile pulling, compared with the traditional static pile pulling or mechanical crushing method, the vibration pile pulling efficiency can be improved by more than 5 times, especially suitable for the project with urgent construction period, the equipment rental and operation cost is lower than the full-rotation drill, especially suitable for small and medium-sized projects, the vibration pile pulling does not produce the dust and noise pollution caused by blasting or crushing, and the pile body can be completely recycled, in line with the green construction trend, and the high-frequency vibration has small disturbance to the surrounding soil.

Description

Technical Field

[0001] This invention relates to the field of building construction, and in particular to a method for vibratory driving and extraction of ultra-long precast piles. Background Technology

[0002] When facing underground obstacles, shield tunneling typically avoids them. However, in the complex environment of central urban areas, most routes cannot be adjusted, leaving only options such as pile removal and obstacle clearing or using the shield machine to cut through the pile foundations to directly pass through. Currently, the application of shield machine equipment to cut through pile foundations is relatively mature, but the difficulty in controlling settlement in the surrounding environment remains significant, and special modifications to the shield machine cutterhead and cutting tools are required. Therefore, the pile removal and obstacle clearing method is generally adopted. When the shield tunnel route passes through the pile foundation removal area of ​​building groups, if there are residual piles, unidentified pile foundations, concrete fragments, reinforcing bars, and other obstacles within the shield excavation area, it may cause equipment failures such as shield machine cutterhead jamming and screw conveyor blockage. Summary of the Invention

[0003] The purpose of this invention is to address the shortcomings of existing technologies by proposing a method for constructing ultra-long precast piles using vibration-driven pipe extraction.

[0004] To achieve the above objectives, the present invention adopts the following technical solution, comprising the following steps:

[0005] S1. Locate the pile extraction position. Use Huace RTK to determine the pile center and mark the determined pile position with steel nails or red paint. Draw a circle with the same diameter as the steel casing as the center of the circle.

[0006] S2. Determine the pile head location. Based on the design location of the equipment foundation piles, excavate trenches and expose the pile heads. Determine the pile locations that need to be removed. Excavate and break up the reinforced concrete foundation to expose the tops of each pile to be removed in the foundation.

[0007] S3. Place the steel column. Use a crawler crane to lift the 600mm diameter steel column with the required rigidity and vibratory hammer to vibrate and sink the steel column to 50-100cm above the design elevation (the bottom of the square pile). During the sinking process, control the verticality.

[0008] S4. After the pile body is lowered into place, lock the pile body with the pre-embedded shaft pin, start the hydraulic vibratory hammer, and gradually increase the vibration frequency until the pile body begins to float. The floating speed can be controlled by adjusting the vibration frequency and amplitude. The crane pulls the pile body out of the ground. Repeat this process until all piles are pulled out. If an abandoned pile is encountered, use a pickaxe to break it and transport the concrete block away.

[0009] S5. Pile extraction and backfilling: The gaps between piles should be backfilled with homogeneous materials. Within 13.6m of the outer contour of the shield structure, clay balls and cement mortar should be used for backfilling to ensure compaction and guarantee that the strength is not lower than that of the original soil.

[0010] Furthermore, in steps S3 and S4, roadbed boxes should be laid on soft ground to ensure construction safety.

[0011] Furthermore, in steps S3 and S4, a 150T crawler crane and an 8.5T vibratory hammer are used. Rubber vibration damping pads are added between the vibratory hammer and the clamps and slings. Anti-vibration trenches are set up (especially on the side adjacent to sensitive buildings). If necessary, temporary sound barriers are erected. The upward pull is controlled at a uniform speed. The pressure gauge and data are closely observed. If the resistance increases sharply, it should be stopped immediately and the cause should be analyzed (such as encountering obstacles or pile breakage). Forced lifting is not allowed.

[0012] Furthermore, in step S4, the crane pulls the pile out of the ground to a corresponding height, with the length pulled out preferably being 8 to 10 meters.

[0013] Furthermore, in step S4, when starting the vibratory hammer, the vibration frequency should begin from a low frequency and gradually be adjusted to the optimal working frequency. The duration of each continuous vibration should be strictly controlled to avoid excessive disturbance and liquefaction of the soil around the pile, which could lead to sudden sinking or tilting of the pile. An intermittent process of "vibration-static extraction-re-vibration" should be adopted. During construction, a theodolite or plumb bob should be used to monitor the verticality of the pile, and any deviation should be adjusted immediately.

[0014] Furthermore, in steps S3 and S4, after the pile extraction is completed, the coordinates of each pile are collected, recorded, and marked on the drawings. The length of the extracted pile is measured on-site, recorded, and the pile tip is checked to determine the integrity of the extracted pile.

[0015] In step S5, cement grout is injected immediately after the pile is pulled out. The amount of cement grout to be injected is calculated based on the hole depth and diameter to ensure that the filling coefficient is greater than 1. If the hole shrinkage is severe and the cement grout filling coefficient is small, WSS grouting is performed on the ground for auxiliary reinforcement.

[0016] Furthermore, in step S4, the vibration sound is closely monitored during the pile extraction process, and the pile body is observed for abnormal swaying or crack expansion. For concrete piles, special attention is paid to prevent pile breakage when the pile is pulled to the second half.

[0017] The present invention has the following beneficial effects:

[0018] In this invention, a high-frequency vibratory hammer is driven by a hydraulic system to generate vertical vibration waves that are transmitted to the pile body, causing the soil around the pile to liquefy or loosen, significantly reducing the frictional resistance between the pile and the soil. At the same time, high-pressure water jetting is used to impact the side of the pile and soil, destroying the side frictional resistance of the pile, thereby achieving rapid pile extraction. Compared with traditional static pile extraction or mechanical crushing methods, the efficiency of vibratory pile extraction can be increased by more than 5 times, which is especially suitable for projects with tight schedules.

[0019] In this invention, a hydraulic high-frequency vibratory hammer is typically mounted on an excavator or a special pile frame. It combines mobility and power output stability, has lower requirements for the working surface, and can be used in narrow spaces (such as around basements or near buildings), making it superior to large equipment such as full-rotation drilling rigs.

[0020] In this invention, vibratory driven pile extraction achieves efficient pile extraction by reducing the side friction between the pile and the soil. It has a fast construction speed, minimal impact on the surrounding environment, wide applicability, significantly improves the success rate of deep pile extraction, and reduces the workload of subsequent foundation treatment.

[0021] In this invention, the equipment rental and operating costs are lower than those of full-rotation drilling rigs, making it particularly suitable for small and medium-sized projects. Vibration pile extraction does not generate dust or noise pollution from blasting or breaking, and the pile body can be completely recycled, which is in line with the trend of green construction. High-frequency vibration has less disturbance to the surrounding soil, and the impact on adjacent pile foundations or underground pipelines is low. With the addition of monitoring measures, risks can be further controlled. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the overall three-dimensional structure of the device of the present invention. Detailed Implementation

[0023] like Figure 1 As shown, the vibratory driving and extraction method for ultra-long precast piles includes the following steps:

[0024] Construction Preparation: On-site, 600mm diameter steel lattice columns are used as pile extraction sleeves. Simultaneously, water jetting devices, a 150T crawler crane, an 8.5T vibratory hammer, and a Huace RTK system are installed at the base of the steel lattice columns. Rubber vibration damping pads are added between the vibratory hammer and the clamps and slings. Anti-vibration trenches are constructed (especially on the side adjacent to sensitive buildings). Temporary sound barriers are erected if necessary. The rubber vibration damping pads effectively reduce the vibration transmission generated by the vibratory hammer during operation, minimizing the impact on the surrounding environment and equipment. The anti-vibration trenches utilize their depth and width to form a physical barrier, further blocking the propagation of vibration waves. The temporary sound barriers significantly reduce noise pollution during construction, creating a relatively quiet environment for the surrounding sensitive areas. Before construction, all equipment must be thoroughly inspected and tested to ensure stable water pressure in the water jetting device, accurate RTK positioning, and that the performance parameters of the crawler crane and vibratory hammer meet construction requirements. Obstacles in the construction site are cleared, and the site is leveled to ensure smooth equipment access and operating space.

[0025] S1. Locating the location of the pile to be removed: After the construction preparation stage is completed, the pile positioning stage is entered. Huace RTK is used to accurately measure the coordinates of the precast pile to be removed, determine the center point of the pile position, and draw a circle with the same diameter as the steel sleeve as the center to ensure that the steel lattice column can be accurately fitted into the pile body.

[0026] S2. Determine the pile head location. Based on the design location of the equipment foundation piles, excavate trenches and expose the pile heads. Determine the pile locations that need to be removed. Excavate and break up the reinforced concrete foundation to expose the tops of each pile to be removed in the foundation.

[0027] Due to the high power and lifting height of the EP240 vibratory hammer, coupled with the large weight of the 150T crawler crane, it is necessary to consider laying roadbed boxes on the soft foundation to ensure construction safety. During the pile extraction process, it is necessary to excavate the pile head, with an excavation depth of approximately 2.5m. During excavation, attention should be paid to slope excavation, ensuring a slope ratio of 1:2. Furthermore, during the pile extraction process, the crawler crane must maintain a safe distance of more than 8m between the tracks and the trench slope.

[0028] S3. Place the steel column. Use a crawler crane to lift the 600mm diameter steel column with the required rigidity and vibratory hammer to vibrate and sink the steel column to 50-100cm above the design elevation (the bottom of the square pile). During the sinking process, control the verticality.

[0029] Among them, 600mm diameter steel lattice columns were used as pile extraction sleeves on site. At the same time, water jetting devices were installed at the bottom of the steel lattice columns. During the vibration and sinking process of the steel lattice columns, water was jetted out from the water jetting device at the bottom of the columns in the form of high pressure through the water pipes embedded in the steel lattice columns. This cuts the soil, reduces the friction between the lattice columns and the soil, and improves the sinking efficiency of the steel lattice columns.

[0030] When the vibratory driven pipe is lowered into the steel column, the soil reaction force pushes the pin shaft to move up the slope, allowing the column to move downwards. When the pile extraction is started, the lifting force of the vibratory hammer and the self-weight of the soil cause the pin shaft to move down and bite the end of the pile. At the same time, the lifting equipment (such as a crawler crane) achieves synchronous lifting through a force-displacement dual control system to avoid pile breakage due to uneven extraction speed.

[0031] S4. After the pile body is lowered into place, lock the pile body with the pre-embedded shaft pin, start the hydraulic vibratory hammer, and gradually increase the vibration frequency until the pile body begins to float. The floating speed can be controlled by adjusting the vibration frequency and amplitude. The crane pulls the pile body out of the ground. The length of the pullout should be 8-10m. Repeat this process until all piles are pulled out. If an abandoned pile is encountered, use a pickaxe to break it and transport the concrete block away.

[0032] For the soil and debris generated during the pile extraction process, excavators should be used in a timely manner to remove them, keep the construction site clean, and avoid the accumulation of materials affecting subsequent operations. After the pile is pulled out to a certain height on the ground, it should be firmly clamped with special clamps to prevent the pile from shaking or falling. Then, a crawler crane should be used to smoothly transfer the pile to the designated stacking area. When stacking, it should be classified and stacked according to length and model, and the stacking height should not exceed 2 layers to ensure stacking safety. After each pile extraction operation is completed, the steel lattice column, vibratory hammer and water jetting device should be inspected and maintained. The soil and debris attached to the surface of the equipment should be cleaned, and the connection parts should be checked for looseness to ensure that the equipment is always in good working condition and ready for the extraction of the next pile.

[0033] When starting the vibratory hammer, the vibration frequency should start from a low frequency and gradually be adjusted to the optimal working frequency. The duration of each continuous vibration should be strictly controlled to avoid excessive disturbance and liquefaction of the soil around the pile, which could lead to sudden sinking or tilting of the pile. An intermittent process of "vibration-static extraction-re-vibration" should be adopted. During construction, a theodolite or plumb bob should be used to monitor the verticality of the pile. If any deviation is found, it should be adjusted immediately.

[0034] During the pile extraction process, the vibration sound is closely monitored, and the pile body is observed for abnormal swaying or crack expansion. For concrete piles, special attention is paid to prevent pile breakage when the pile is pulled to the second half. The pressure of the hydraulic system is also monitored in real time, converted into the pile extraction force, and compared with the theoretical calculation value to determine whether there is any abnormality.

[0035] During the pile extraction process, control the upward speed to be uniform, closely observe the pressure gauge and data, and stop immediately when the resistance increases sharply. Analyze the cause (such as encountering an obstacle or the pile breaking). Do not force the pile to be pulled out.

[0036] After the pile extraction is completed, the coordinates of each pile are collected and recorded, and marked on the drawings. The length of the extracted pile is measured on site, recorded, and the pile tip is checked to determine the integrity of the extracted pile.

[0037] S5. Pile Extraction and Backfilling: After the pile extraction and obstacle clearing are completed, the pile extraction holes should be backfilled in a timely manner. The gaps between the extracted piles should be backfilled with homogeneous materials. Within 13.6m of the outer contour of the shield structure, clay balls and cement mortar should be used for backfilling to ensure compaction and guarantee that the strength is not lower than that of the original soil. To ensure that the pile hole backfilling is compact, cement grout should be injected immediately after the pile is extracted. The amount of cement grout to be injected should be calculated according to the hole depth and diameter to ensure that the filling coefficient is greater than 1. If the hole shrinkage is serious and the cement grout filling coefficient is small, WSS grouting should be carried out on the ground for auxiliary reinforcement. The water-cement ratio is 1:1, the cement content is 20%, the verticality of the pilot hole is no more than 1 / 300, the grouting pressure is 0.5-0.8 MPa, and the flow rate is 55 L / min. During the grouting process, close attention must be paid to changes in grouting pressure and flow rate. If the pressure suddenly increases or the flow rate suddenly decreases, grouting should be suspended to check for pipe blockage or abnormal ground conditions. Construction can only continue after the problem is resolved. After grouting is completed, curing is required for more than 7 days to ensure that the backfill material reaches the design strength. At the same time, surface settlement monitoring should be carried out in the backfill area for no less than 14 days. If the settlement is found to exceed the warning value, reinforcement measures such as supplementary grouting should be taken in time to ensure the safety of subsequent construction and the stability of the surrounding environment.

[0038] In this embodiment, the core principle of the hydraulic high-frequency vibratory hammer pile extraction method is to use high-frequency vibration to cause resonance in the pile-soil system, thereby destroying the structural strength of the soil around the pile and significantly reducing the pile side friction. At the same time, a customized steel lattice column is used as the pile extraction sleeve, and a high-pressure water jet device and a one-way self-locking mechanism are set at the bottom of the steel lattice column to ensure the integrity of the pile extraction, thus achieving efficient pile extraction. Its key technologies mainly include high-frequency vibration wave transmission, hydraulic power system control, and adaptive adjustment of clamping force. Compared with traditional static pile extraction or mechanical crushing methods, vibratory pile extraction efficiency can be increased by more than 5 times, which is especially suitable for projects with tight schedules. It is usually carried by an excavator or a special pile frame with a hydraulic high-frequency vibratory hammer, which has both mobility and power output stability. It has lower requirements for the working surface and can be constructed in narrow sites (such as around basements or near buildings). It is superior to large equipment such as full-rotation drilling rigs. Overall, vibratory pipe driving pile extraction achieves efficient pile extraction by reducing the side friction between the pile and the soil. It has a fast construction speed, little impact on the surrounding environment, wide applicability, significantly improves the success rate of deep pile extraction, and reduces the amount of subsequent foundation treatment work.

[0039] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for vibratory driving and extraction of ultra-long precast piles, characterized in that, Includes the following steps: S1. Locate the pile extraction position. Use Huace RTK to determine the pile center and mark the determined pile position with steel nails or red paint. Draw a circle with the same diameter as the steel casing as the center of the circle. S2. Determine the pile head location. Based on the design location of the equipment foundation piles, excavate trenches and expose the pile heads. Determine the pile locations that need to be removed. Excavate and break up the reinforced concrete foundation to expose the tops of each pile to be removed in the foundation. S3. Place the steel column. Use a crawler crane to lift the steel column with a diameter of 550-650mm that meets the required rigidity and vibratory hammer to vibrate and sink the steel column to the design elevation, i.e., 50-100cm above the bottom of the square pile. Control its verticality during the sinking process. S4. After the pile body is lowered into place, lock the pile body with the pre-embedded shaft pin, start the hydraulic vibratory hammer, and gradually increase the vibration frequency until the pile body begins to float. Control the floating speed by adjusting the vibration frequency and amplitude. Then, use a crane to pull the pile body out of the ground. Repeat this process until the entire pile extraction process is completed. If an abandoned pile is encountered, use a pickaxe to break it and transport the concrete block away. S5. Pile extraction and backfilling: The gaps between piles should be backfilled with homogeneous materials. Within 13.6m of the outer contour of the shield structure, clay balls and cement mortar should be used for backfilling to ensure compaction and guarantee that the strength is not lower than that of the original soil.

2. The method for vibratory driving and extraction of ultra-long precast piles according to claim 1, characterized in that: In steps S3 and S4, roadbed boxes should be laid on soft ground to ensure construction safety.

3. The method for vibratory driving and extraction of ultra-long precast piles according to claim 1, characterized in that: In steps S3 and S4, a 150T crawler crane and an 8.5T vibratory hammer are used. Rubber vibration damping pads are added between the vibratory hammer and the clamps and slings. Anti-vibration trenches are set up on the side adjacent to sensitive buildings. Temporary sound barriers are erected if necessary. The upward movement is controlled at a uniform speed. The pressure gauge and data are closely observed. If the resistance increases sharply, it should be stopped immediately and the cause should be analyzed.

4. The method for vibratory driving and extraction of ultra-long precast piles according to claim 1, characterized in that: In step S4, the crane pulls the pile out of the ground by a length of 8 to 10 meters.

5. The method for vibratory driving and extraction of ultra-long precast piles according to claim 1, characterized in that: In step S4, the vibration frequency should start from a low frequency when the vibratory hammer is started, and gradually adjusted to the optimal working frequency. The duration of each continuous vibration should be strictly controlled to avoid excessive disturbance and liquefaction of the soil around the pile, which could lead to sudden sinking or tilting of the pile. An intermittent process of "vibration-static extraction-re-vibration" should be adopted. During construction, a theodolite or plumb bob should be used to monitor the verticality of the pile, and any deviation should be adjusted immediately.

6. The method for vibratory driving and extraction of ultra-long precast piles according to claim 1, characterized in that: In steps S3 and S4, after the pile extraction is completed, the coordinates of each pile are collected, recorded, and marked on the drawings. The length of the extracted pile is measured on-site, recorded, and the pile tip is checked to determine the integrity of the extracted pile.

7. The method for vibratory driving and extraction of ultra-long precast piles according to claim 1, characterized in that: In step S5, cement grout is injected immediately after the pile is pulled out. The amount of cement grout to be injected is calculated based on the hole depth and diameter to ensure that the filling coefficient is greater than 1. If the hole shrinkage is severe and the cement grout filling coefficient is small, WSS grouting is performed on the ground for auxiliary reinforcement.

8. The method for vibratory driving and extraction of ultra-long precast piles according to claim 1, characterized in that: In step S4, the vibration sound is closely monitored during the pile extraction process, and the pile body is observed for abnormal swaying or crack expansion. For concrete piles, special attention is paid to prevent pile breakage when the pile is pulled to the second half.

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