Coastal reclamation vacuum preloading soil PC composite pile construction method and special hole guiding equipment

Abstract

The invention discloses a coastal reclamation vacuum preloading soil PC composite pile construction method and special hole guiding equipment, and the construction method comprises the following steps: S1, carrying out survey lofting in a field after vacuum preloading treatment so as to position and mark the mounting position of each pile body in a PC composite pile; s2, a pile driver body is adopted and matched with special hole guiding equipment to conduct hole guiding in the soil body in the site, shallow obstacles in the soil body are removed, and therefore a mounting hole position is formed; s3, after the depth of the guide hole reaches the designed depth of the PC composite pile, a high-pressure medium is sprayed into the mounting hole position through special guide hole equipment so as to remove impurities at the bottom of the hole; s4, the special hole guiding equipment is lifted away from the hole opening, and a pile driver body is adopted and matched with a vibratory hammer to drive the first pile body in the PC combined pile into the mounting hole position so as to complete mounting of the first pile body; and S5, the steps S2 to S4 are repeated till installation of all the pile bodies is completed, the efficiency is high, the cost is low, obstacle clearing is thorough, the pile forming quality is good, and the high popularization value is achieved.

Description

Technical Field

[0001] This invention relates to the field of building construction technology, and in particular to a construction method and special drilling equipment for vacuum preloading of PC composite piles in coastal dredged and filled soil. Background Technology

[0002] Coastal areas often acquire land for construction through reclamation. The silty, soft soil formed by reclamation has high water content, low strength, and high compressibility, making it unable to directly support the superstructure. Therefore, vacuum preloading is commonly used to reinforce it before construction. This method compacts the soil through drainage consolidation, significantly improving its bearing capacity.

[0003] However, vacuum preloading also brings new construction challenges:

[0004] 1. Numerous obstacles during pile formation: After preloading, a large amount of hard plastic drainage boards (PVDs), sand cushions, and shells and other debris remain in the soil, forming an underground obstacle network.

[0005] 2. Changes in soil properties: After preloading, the strength, density and bearing capacity of the soil are significantly improved, resulting in huge resistance to pile driving.

[0006] 3. Pile body is easily damaged: When constructing PC composite piles (usually a combination of steel pipe piles and Larssen sheet piles) in this type of stratum, the pile tip (especially the thin-walled interlock of Larssen piles) is very likely to collide with hard obstacles, resulting in deformation, tearing or even damage to the pile end, which seriously affects the water-stopping and soil-retaining performance of the support structure.

[0007] 4. High efficiency and low cost: The conventional solution is to increase the power of the piling equipment, but the effect is limited, and the equipment cost, energy consumption and maintenance costs rise sharply, and the construction efficiency remains low.

[0008] Currently, the closest existing technology is to directly use a high-power vibratory hammer for "heavy impact." This approach not only fails to effectively solve the problem of pile damage, but also has significant disadvantages in terms of economy and environmental protection. Summary of the Invention

[0009] To overcome the shortcomings of existing technologies, this invention provides a construction method and dedicated drilling equipment for vacuum preloading of PC composite piles in coastal dredged reclamation soil, which solves the problem that existing technologies cannot effectively solve pile damage and have significant disadvantages in terms of economy and environmental protection.

[0010] To achieve the above objectives, the present invention provides a method for constructing PC composite piles in coastal dredged and reclaimed vacuum preloading soil, comprising the following steps:

[0011] S1. Conduct surveying and layout within the site after vacuum preloading to locate and mark the installation positions of each pile in the PC composite pile;

[0012] S2. Using a pile driver and a special pre-drilling device, pre-drill holes are made in the soil on site and shallow obstacles in the soil are removed to form installation holes.

[0013] S3. After the pilot hole depth reaches the design depth of the PC composite pile, high-pressure medium is sprayed into the installation hole through a special pilot hole equipment to remove debris from the bottom of the hole.

[0014] S4. Lift the special pre-hole device away from the hole opening, and use the pile driver body and vibratory hammer to drive the first pile of the PC composite pile into the installation hole to complete the installation of the first pile.

[0015] S5. Repeat steps S2 to S4 until all piles are installed.

[0016] Preferably, before conducting measurement and layout within the vacuum-preloaded site, the vacuum-preloaded site is leveled and compacted.

[0017] Preferably, when drilling and removing shallow obstacles in the soil, the drilling depth is calculated using Formula 1.

[0018] H = L - (2~3)m (Formula 1)

[0019] Where H is the depth of the pilot hole and L is the design pile length of the PC composite pile.

[0020] Preferably, when high-pressure medium is injected into the hole through a dedicated pilot hole device to remove debris from the bottom of the hole, the bottom of the dedicated pilot hole device is provided with a high-pressure airflow hole for injecting high-speed airflow into the bottom of the hole and a high-pressure water flow hole for injecting high-pressure water flow into the bottom of the hole.

[0021] Preferably, after the first pile of the PC composite pile is driven into the installation hole using a pile driver and a vibratory hammer to complete the installation of the first pile, the installed first pile is inspected and accepted. After the inspection is passed, the pile driver is moved to the next installation position to install the next pile.

[0022] A specialized pre-drilling device, characterized in that it is used in conjunction with a pile driver to achieve the construction of the coastal dredged and preloaded vacuum-loaded PC composite piles, the specialized pre-drilling device comprising:

[0023] A spiral drill rod, wherein spiral fan blades are fixedly installed on the surface of the spiral drill rod;

[0024] A combined drill bit includes a square drill bit located at the bottom of the spiral drill rod and a conical drill bit located at the center of the square drill bit and extending in a direction away from the spiral drill rod. The conical drill bit has at least two high-pressure medium injection holes.

[0025] A drive shaft is located at the top of the auger drill rod and can rotate around its own axis. The first end of the drive shaft is fixedly connected to the auger drill rod through a power output shaft.

[0026] The drive mechanism is located between the second end of the drive shaft and the piling machine body, and is used to drive the drive shaft to rotate around its own axis, thereby driving the spiral drill rod to rotate to achieve pilot hole drilling.

[0027] Preferably, a fixing pin is fixedly installed on the side of the drive mechanism opposite to the transmission shaft for connecting the drive mechanism to the pile driver body, thereby realizing the fixed connection between the equipment and the pile driver body.

[0028] Preferably, a rocker arm is fixedly mounted on the side of the second chain tooth away from the connecting shaft.

[0029] By adopting the above technical solution, the present invention has the following beneficial effects:

[0030] 1) High efficiency and low cost: By pre-drilling, most obstacles are removed, reducing the resistance of subsequent piling by more than 70%, eliminating the need for extra-large piling equipment, increasing construction efficiency by about 40%, and significantly reducing overall costs.

[0031] 2) High quality of pile driving: The method has changed from "passive hard driving" to "active obstacle removal", which fundamentally avoids direct damage to the pile body and interlocking joint, ensuring the complete water-stop curtain effect and support strength of the PC composite pile, and greatly improving the safety and reliability of the foundation pit.

[0032] 3) Thorough clearance and adaptability: The unique high-pressure airflow / water flow hole clearing function can effectively solve the specific problem of plastic drainage board residue, making the adaptability and reliability of this method in vacuum preloading sites far exceed existing technologies.

[0033] 4) High degree of intelligence and standardization: The design of quick-connect interfaces and special equipment makes process switching smooth, facilitates the formation of standardized operating procedures, and is conducive to quality control and large-scale promotion. Attached Figure Description

[0034] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0035] Figure 1 This is a flowchart of the construction method of PC composite piles for vacuum preloading of coastal dredged soil in an embodiment of the present invention.

[0036] Figure 2 This is a schematic diagram of the drilling operation in an embodiment of the present invention.

[0037] Figure 3 This is a schematic diagram of the structure of the dedicated aperture device in an embodiment of the present invention.

[0038] Figure 4 This is a schematic diagram of the structure of the combined pile head in an embodiment of the present invention.

[0039] Figure 5 This is a schematic diagram of the arrangement of PC combined piles in an embodiment of the present invention.

[0040] Figure 6 This is a schematic diagram of the PC combined pile driving construction in an embodiment of the present invention.

[0041] The correspondence between the numbers in the attached diagram is as follows:

[0042] 1-Fixed pin; 2-Drive mechanism; 21-Motor; 22-Precision gear; 3-Auger drill rod; 4-Auger fan blade; 5-Square drill bit; 6-Conical drill bit; 7-High-pressure airflow hole; 8-High-pressure water flow hole; 9-Drive shaft; 10-Power output shaft; 11-Larsen sheet pile; 12-Steel pipe pile; 13-Pile driver body. Detailed Implementation

[0043] The specific embodiments of the present invention will be further described below with reference to the accompanying drawings. It should be noted that these descriptions are for the purpose of aiding understanding the present invention, but do not constitute a limitation thereof. Furthermore, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0044] Please see Figures 1 to 6 As shown in the figure, this invention provides a method for constructing PC composite piles in coastal dredged and vacuum-preloaded soil, including the following steps:

[0045] S1 Construction Preparation and Surveying

[0046] Measurement and layout are carried out in the site after vacuum preloading to locate and mark the installation position of each pile in the PC composite pile (using a total station and other high-precision equipment to measure and lay out the pile, accurately locate the pile core position of each pile, and make clear marks with wooden stakes or lime).

[0047] S2 pilot hole and obstacle removal construction

[0048] The piling machine body (in this embodiment, a tracked piling machine is used to travel to the predetermined pile position) and a special pre-drilling device are used to drill holes in the soil in the site and remove shallow obstacles in the soil to form the installation hole position. It should be noted that before drilling and clearing the obstacles, the piling machine body and the special pre-drilling device need to be installed in place.

[0049] S3 High Pressure Medium Cleaning

[0050] After the pilot hole reaches the designed depth of the PC composite pile, a high-pressure medium is sprayed into the installation hole using a special pilot hole equipment to remove debris from the bottom of the hole.

[0051] S4 equipment switching and PC combined pile driving

[0052] The special pre-drilling equipment is lifted away from the borehole, and the first pile body of the PC composite pile is driven into the installation hole by the pile driver body and vibratory hammer to complete the installation of the first pile body. During construction, the steel pipe piles are constructed first, and then the Larssen steel sheet piles are constructed.

[0053] S5 Acceptance and Cyclic Operations

[0054] Repeat steps S2 to S4 until all piles are installed, such as... Figure 4 The diagram shown is a schematic diagram of the arrangement of PC composite piles in an embodiment of the present invention. The PC composite piles include steel pipe piles 12 and Larssen steel sheet piles 11 that are interlocked with each other. Their structural composition and connection method are all existing technologies publicly known in the art, and therefore will not be described in detail.

[0055] Furthermore, in this embodiment, before conducting measurement and layout within the vacuum pre-compression treated site, the vacuum pre-compression treated site is leveled and compacted.

[0056] Furthermore, when drilling and removing shallow obstacles in the soil, the drilling depth is calculated using Formula 1.

[0057] H = L - (2~3)m (Formula 1)

[0058] Where H is the depth of the pilot hole and L is the design pile length of the PC composite pile.

[0059] Please see Figures 2 to 4 As shown, when high-pressure medium is injected into the hole through a special pilot hole device to remove debris from the bottom of the hole, the bottom of the special pilot hole device is reserved with a high-pressure airflow hole 7 for injecting high-speed airflow into the bottom of the hole and a high-pressure water flow hole 8 for injecting high-pressure water flow into the bottom of the hole. The injection of high-speed gas and high-pressure water flow can thoroughly blow away or wash away the plastic drainage board debris and mud remaining at the bottom of the hole, preventing them from re-aggregating during subsequent piling and affecting the bearing capacity of the pile tip or damaging the pile tip.

[0060] Please see Figure 1 As shown in this embodiment, after the first pile of the PC composite pile is driven into the installation hole by the pile driver body and the vibratory hammer to complete the installation of the first pile, the installed first pile is inspected (in this embodiment, the verticality of the pile is checked by the inclinometer and the elevation of the pile top is measured by the level to ensure that it meets the design and specification requirements). After the inspection is passed, the pile driver body is moved to the next installation position to install the next pile.

[0061] Please see Figures 2 to 5 As shown, this embodiment of the invention also discloses a dedicated pre-drilling device for use in conjunction with the pile driver body 13 to achieve the construction of the aforementioned coastal dredged vacuum preloaded soil PC composite piles. The dedicated pre-drilling device includes a spiral drill rod 3, a combined drill bit, a drive shaft 9, and a drive mechanism 2. The spiral drill rod 3 has spiral fan blades 4 fixedly mounted on its surface. The combined drill bit includes a square drill bit 5 located at the bottom of the spiral drill rod 3 and a conical drill bit 6 located at the center of the square drill bit 5 and extending towards the side opposite to the spiral drill rod 3. The conical drill bit 6 has at least two high-pressure medium injection holes pre-drilled on it. The drive shaft 9 is located at the top of the spiral drill rod 3 and can rotate around its own axis. The first end of the drive shaft 9 is fixedly connected to the spiral drill rod 3 via a power output shaft 10. The drive mechanism 2 is located between the second end of the drive shaft 9 and the pile driver body 13 and is used to drive the drive shaft 9 to rotate around its own axis, thereby driving the spiral drill rod 3 to rotate to achieve pre-drilling.

[0062] It should be noted that in this embodiment, both the square drill bit 5 and the conical drill bit 6 are made of alloy. During the startup of the piling machine and the rotation and sinking of the auger drill rod 3 via the drive system, the square drill bit 5 at the bottom, with its sharp cutting edges, first shears and breaks down hard underground obstacles such as plastic drainage boards. The alloy conical drill bit 6, following closely behind, is responsible for cutting and crushing the soil. The broken soil is continuously transported to the surface by the spiral fan blades 4. The conical drill bit 6 is equipped with two high-pressure medium injection holes: a high-pressure airflow hole 7 for injecting high-speed airflow into the bottom of the hole and a high-pressure water flow hole 8 for injecting high-pressure water.

[0063] Furthermore, a fixing pin 1 is fixedly installed on the side of the drive mechanism 2 opposite to the transmission shaft 9 to connect the drive mechanism 2 to the pile driver body 13, thereby realizing the fixed connection between the equipment and the pile driver body 13. In this embodiment, the drive mechanism 2 includes a motor 21 and a precision gear 22 (the structure and connection relationship of the motor and precision gear are well known in the art and will not be described in detail here), and its specific function is to drive the transmission shaft 9 to generate rotational force.

[0064] In step S4, after the special pre-drilling device is lifted away from the hole, the fixing pin 1 is pulled out to remove the device. Then, the pile to be installed is hoisted to the corresponding installation hole position, and the same set of fixing pin 1 and power output shaft 10 interface is used to rigidly connect the pile to the vibratory hammer. Align it with the pre-drilled installation hole position, and rely on the weight of the pile and the high-frequency vibration of the vibratory hammer to drive the pile into the design elevation quickly and smoothly.

[0065] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings, but the present invention is not limited to the described embodiments. For those skilled in the art, various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention, and these variations still fall within the protection scope of the present invention.

Claims

1. A construction method for vacuum preloading PC composite piles in coastal dredged and filled soil, characterized in that, Includes the following steps: S1. Conduct surveying and layout within the site after vacuum preloading to locate and mark the installation positions of each pile in the PC composite pile; S2. Using a pile driver and a special pre-drilling device, pre-drill holes are made in the soil on site and shallow obstacles in the soil are removed to form installation holes. S3. After the pilot hole depth reaches the design depth of the PC composite pile, high-pressure medium is sprayed into the installation hole through a special pilot hole equipment to remove debris from the bottom of the hole. S4. Lift the special pre-hole device away from the hole opening, and use the pile driver body and vibratory hammer to drive the first pile of the PC composite pile into the installation hole to complete the installation of the first pile. S5. Repeat steps S2 to S4 until all piles are installed.

2. The construction method for vacuum preloading soil PC composite piles in coastal reclamation as described in claim 1, characterized in that, Before conducting measurements and setting out in the vacuum-preloaded site, the site is leveled and compacted.

3. The construction method for vacuum preloading soil PC composite piles in coastal reclamation as described in claim 1, characterized in that, When drilling and removing shallow obstacles in the soil, the drilling depth is calculated using Formula 1. H = L - (2~3)m (Formula 1) where H is the depth of the pilot hole and L is the design pile length of the PC composite pile.

4. The construction method for vacuum preloading soil PC composite piles in coastal reclamation as described in claim 1, characterized in that, When high-pressure medium is injected into the hole through a special pilot hole device to remove debris from the bottom of the hole, the bottom of the special pilot hole device is reserved with a high-pressure airflow hole for injecting high-speed airflow into the bottom of the hole and a high-pressure water flow hole for injecting high-pressure water flow into the bottom of the hole.

5. The construction method for vacuum preloading soil PC composite piles in coastal reclamation as described in claim 1, characterized in that, After the first pile in the PC composite pile is driven into the installation hole using a pile driver and vibratory hammer to complete the installation of the first pile, the installed first pile is inspected and accepted. After the inspection is passed, the pile driver is moved to the next installation position to install the next pile.

6. A dedicated drilling device, characterized in that, The dedicated pre-drilling equipment, used in conjunction with the pile driver body to achieve the construction of the coastal dredged vacuum preloaded soil PC composite pile as described in claim 1, includes: A spiral drill rod, wherein spiral fan blades are fixedly installed on the surface of the spiral drill rod; A combined drill bit includes a square drill bit located at the bottom of the spiral drill rod and a conical drill bit located at the center of the square drill bit and extending in a direction away from the spiral drill rod. The conical drill bit has at least two high-pressure medium injection holes. A drive shaft is located at the top of the auger drill rod and can rotate around its own axis. The first end of the drive shaft is fixedly connected to the auger drill rod through a power output shaft. The drive mechanism is located between the second end of the drive shaft and the piling machine body, and is used to drive the drive shaft to rotate around its own axis, thereby driving the spiral drill rod to rotate to achieve pilot hole drilling.

7. The dedicated pilot hole device as described in claim 6, characterized in that, A fixing pin is fixedly installed on the side of the drive mechanism opposite to the transmission shaft to connect the drive mechanism to the pile driver body, thereby realizing the fixed connection between the equipment and the pile driver body.

Images