In-situ mixing steel pipe pile construction system and method applied to coral reef geology

Abstract

The present invention discloses an in-situ mixing steel pipe pile construction system and method applied to coral reef geology. The system includes: a steel pipe pile, which includes an integrally formed upper standard section and a lower enlarged diameter section, and the side surface of the steel pipe pile has a plurality of openings; a rotary power device, which is connected with a drill pipe, and the drill pipe is a hollow rod; a grouting pipeline; an under-reaming bit. The method includes: preparation; drilling, when the under-reaming bit drills to the enlarged diameter section at the bottom of the steel pipe pile, the under-reaming bit is enlarged in diameter and continues to drill; injecting the solidifying slurry into the bottom of the hole through the drill pipe, and driving the rotation and stirring of the under-reaming bit through the rotation of the drill pipe to mix evenly with the coral reef sand, and the solidifying slurry-coral reef sand mixture fills the inside and outside of the standard section through the openings on the steel pipe pile. The present invention combines the construction methods of in-situ mixing piles and steel pipe piles, integrates the three processes of drilling, pile sinking, and grouting into one process, and has the advantages of high bearing capacity, high construction efficiency, and low project cost.

Description

Technical Field

[0001] The present invention relates to the technical field of pile foundation construction. More specifically, the present invention relates to an in-situ mixing steel pipe pile construction system and method applied to coral reef geology. Background Art

[0002] Driven steel pipe piles are low in cost and fast in construction process, and are widely used in marine engineering. Although the technologies related to driven steel pipe piles are relatively mature, in coral reef formations, the pile driving process will damage fragile particles and soil structures, resulting in very low side friction resistance of the steel pipe piles, which may cause problems such as "pile slipping" or vertical bearing capacity not meeting the design requirements. At present, foreign countries generally use drilled grouted steel pipe piles to solve this problem, that is, first drill a hole, then clean the hole, then insert the steel pipe pile, and finally grout. Although this method solves the problem of low side friction resistance of the steel pipe pile, it has many processes, a long construction period, high cost, and cracks are likely to occur after the solidified grout is consolidated. Post-grouting of driven steel pipe piles can also solve this problem to a certain extent, but it is difficult to ensure the grouting coverage rate, the side friction resistance of the pile is unstable, and pressure grouting may cause certain damage to the soil structure, instead reducing its bearing capacity. At the same time, there is often a covering rock or highly consolidated soil on the surface of coral reef geology, and the steel pipe pile is prone to curling during the driving process, resulting in the overall scrapping of the steel pipe pile. Summary of the Invention

[0003] An object of the present invention is to provide an in-situ mixing steel pipe pile construction system and method applied to coral reef geology, which combines the construction methods of in-situ mixing piles and steel pipe piles, integrates the three processes of drilling, pile sinking, and grouting into one process, and has the advantages of high bearing capacity, high construction efficiency, and low project cost.

[0004] To achieve these and other advantages in accordance with the present invention, there is provided an in-situ mixing steel pipe pile construction system applied to coral reef geology, including: a steel pipe pile, which is fixed at a designed position by a pile driver, the steel pipe pile includes an integrally formed upper standard section and a lower enlarged diameter section, and the side surface of the steel pipe pile has a plurality of openings; a rotary power device, which is installed on the upper part of the steel pipe pile, the rotary power device is connected with a drill pipe, which is located inside the steel pipe pile, and the drill pipe is a hollow rod; a grouting pipeline, one end of which is communicated with the drill pipe, and the other end of the grouting pipeline is connected with an external grouting device; an underreaming bit, which is connected to the bottom of the drill pipe and does not interfere with the communication between the bottom of the drill pipe and the inside of the steel pipe pile.

[0005] Preferably, the diameter of the enlarged diameter section is greater than 0.1 times the diameter of the standard section.

[0006] Preferably, the under-reaming bit comprises: a hydraulic telescopic rod fixedly connected to the drill pipe, with the bottom end of the variable-diameter rod of the hydraulic telescopic rod connected to the drill bit body; a fixing member fixedly sleeved on the hydraulic telescopic rod; a pair of reaming rods symmetrically located on both sides of the hydraulic telescopic rod, with the upper ends of the reaming rods hinged to the fixing member; and a pair of connecting rods also symmetrically located on both sides of the hydraulic telescopic rod, with the upper ends of the connecting rods hinged to the reaming rods and the lower ends of the connecting rods hinged to the drill bit body.

[0007] Preferably, the side surface of the bottom of the drill pipe has a plurality of small holes communicating with the inside of the steel pipe pile.

[0008] Preferably, the under-reaming diameter of the under-reaming bit is slightly smaller than the diameter of the reaming section and slightly larger than the diameter of the standard section.

[0009] The present invention also provides an in-situ mixing steel pipe pile construction method applied to coral reef geology, comprising the following steps:

[0010] Step 1: Measuring and positioning, installing the steel pipe pile at the designed position and fixing it through a pile driver. The steel pipe pile enters the soil under its own weight for a certain part, and at the same time, the solidifying slurry is prepared and the grouting pipeline is connected.

[0011] Step 2: Install the rotary power device on the upper part of the steel pipe pile, put the under-reaming bit into the steel pipe pile through the drill pipe, and drill a hole.

[0012] Step 3: When the under-reaming bit drills to the reaming section at the bottom of the steel pipe pile, expand the under-reaming bit and continue drilling. The hole diameter formed is slightly larger than the standard pile diameter of the steel pipe pile and slightly smaller than the pile diameter of the reaming section. During the process of drilling and forming the hole, the solidifying slurry is always injected into the bottom of the hole through the drill pipe, and the rotary stirring action of the drill pipe drives the rotation of the under-reaming bit to mix evenly with the coral reef sand.

[0013] Step 4: After drilling to a certain depth, the bottom of the steel pipe pile will be basically void, so the steel pipe pile will continue to enter the soil under its own weight, and the solidifying slurry-coral reef sand mixture fills the inside and outside of the standard section through the openings on the steel pipe pile.

[0014] Step 5: Drill to the designed bottom elevation, continue to inject the solidifying slurry and rotate the under-reaming bit, stir for a period of time until the end of the steel pipe pile is grouted densely. Finally, reduce the diameter of the under-reaming bit and pull it out. After waiting for the solidifying slurry-coral reef sand mixture to coagulate and complete the curing, the construction of the in-situ mixing steel pipe pile is completed.

[0015] The present invention has at least the following beneficial effects:

[0016] The present invention combines the construction methods of in-situ mixing piles and steel pipe piles, integrates the three processes of drilling, pile sinking, and grouting into one process, solves the problems of low side friction resistance of driven steel pipe piles and high cost of drilled grouting steel pipe piles under coral reef geological conditions, and has the advantages of high bearing capacity, high construction efficiency, and low project cost.

[0017] Other advantages, objectives, and features of the present invention will be partially reflected by the following description and partially understood by those skilled in the art through the research and practice of the present invention. Description of the Drawings

[0018] Figure 1 It is a schematic diagram of the construction method of the in-situ mixing steel pipe pile in the present invention.

[0019] Figure 2 It is a partial enlarged view of the bottom of the in-situ mixing steel pipe pile during the construction process.

[0020] Figure 3 It is an elevation view of the steel pipe pile in the present invention.

[0021] Figure 4 It is a schematic diagram before the reaming bit in the present invention expands the diameter;

[0022] Figure 5 It is a schematic diagram after the reaming bit in the present invention expands the diameter.

[0023] Description of the Reference Numerals:

[0024] 1. Pile driver, 2. Steel pipe pile, 3. Rotary power device, 4. Drill pipe, 5. Reaming bit, 6. Grouting pipeline, 2-1. Standard section, 2-2. Diameter-expanded section, 2-3. Opening, 5-1. Reducing rod, 5-2. Hydraulic telescopic rod, 5-3. Fixing part, 5-4. Diameter-expanding rod, 5-5. Connecting rod, 5-6. Bit body. Detailed Embodiments

[0025] The following further describes the present invention in detail with reference to the drawings, so that those skilled in the art can implement it according to the description in the specification.

[0026] It should be noted that the experimental methods described in the following implementation plans are all conventional methods unless otherwise specified, and the reagents and materials can be obtained from commercial channels unless otherwise specified; in the description of the present invention, the terms "lateral", "longitudinal", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be construed as a limitation to the present invention.

[0027] As Figures 1 to 3 shown, the present invention provides an in-situ mixing steel pipe pile construction system applied to coral reef geology, including: a steel pipe pile 2, which is fixed at the designed position by a pile driver 1. The steel pipe pile 2 includes an integrally formed upper standard section 2-1 and a lower enlarged diameter section 2-2. The side of the steel pipe pile 2 has a plurality of openings 2-3; a rotary power device 3, which is installed on the upper part of the steel pipe pile 2. The rotary power device 3 is connected with a drill pipe 4, which is located inside the steel pipe pile 2. The drill pipe 4 is a hollow rod; a grouting pipeline 6, one end of which is communicated with the drill pipe 4, and the other end of the grouting pipeline 6 is connected to an external grouting device; an under-reaming bit 5, which is connected to the bottom of the drill pipe 4 and does not interfere with the communication between the bottom of the drill pipe 4 and the inside of the steel pipe pile 2.

[0028] The present invention also provides an in-situ mixing steel pipe pile construction method applied to coral reef geology, including the following steps:

[0029] Step 1: Measuring and positioning. Install the steel pipe pile 2 at the designed position and fix it through the pile driver 1. The steel pipe pile 2 enters the soil by its own weight for a certain part, and at the same time, prepare the solidified slurry and connect the grouting pipeline 6.

[0030] Step 2: Install the rotary power device 3 on the upper part of the steel pipe pile 2, and put the under-reaming bit 5 into the steel pipe pile 2 through the drill pipe 4 and drill to form a hole.

[0031] Step 3: When the under-reaming bit 5 drills to the enlarged diameter section 2-2 at the bottom of the steel pipe pile 2, expand the under-reaming bit 5 and continue drilling. The diameter of the formed hole is slightly larger than the diameter of the standard section 2-1 of the steel pipe pile 2 and slightly smaller than the diameter of the enlarged diameter section 2-2. During the process of drilling to form a hole, always inject the solidified slurry into the bottom of the hole through the drill pipe 4, and drive the rotation and stirring of the under-reaming bit through the rotation of the drill pipe 4 to mix evenly with the coral reef sand.

[0032] Step 4: After drilling to a certain depth, the bottom of the steel pipe pile 2 will be basically void, so the steel pipe pile will continue to enter the soil under its own weight, and the solidified slurry-coral reef sand mixture fills the inside and outside of the standard section 2-1 through the openings 2-3 on the steel pipe pile 2.

[0033] Step 5: Drill to the designed bottom elevation, continue to inject the solidifying slurry and rotate the reaming bit, stir for a period of time until the grouting at the end of the steel pipe pile 2 is dense; finally, reduce the diameter of the under-reaming bit 5 and pull it out. After waiting for the solidifying slurry - coral reef sand mixture to coagulate and the curing to be completed, the construction of the in-situ mixing steel pipe pile 2 is completed.

[0034] In the above technical solution, the steel pipe pile 2 is composed of a standard section 2-1 and a reaming section 2-2. The setting of the reaming section 2-2 can, on the one hand, make a certain gap between the standard section 2-1 of the steel pipe pile 2 and the side of the coral reef geology. The mixture after the solidifying slurry and the coral reef sand are mixed can penetrate into the side gap through the openings 2-3 provided on the steel pipe pile 2, ensuring the bonding force between the steel pipe pile 2 and the coral reef and improving the side friction resistance of the steel pipe pile. On the other hand, when the under-reaming bit 5 is under-reaming, the hole-forming diameter is slightly smaller than the diameter of the reaming section 2-2. The outer side of the bottom of the reaming section 2-2 can be stably located on the surrounding undrilled soil mass, as Figure 2 shown, thus ensuring the stability of the steel pipe pile 2, and also ensuring that the center line of the steel pipe pile 2 can always be basically coincident with the center line of the finally formed hole, ensuring the smooth and stable progress of the hole forming. The rotary power device 3 is a conventional existing drilling machine, which is connected to the drill pipe 4 and can drive the drill pipe 4 to move downward and rotate. The grouting pipeline 6 presses the solidifying slurry into the drill pipe 4 through the grouting device, and is located inside and outside the steel pipe pile 2 through the drill pipe 4. A plurality of small holes communicating with the inside of the steel pipe pile 2 are provided on the side of the bottom of the drill pipe 4. After the solidifying slurry used is designed through mix proportion, it can form a certain strength after being mixed with the coral reef sand, about 5 MPa. The under-reaming bit 5 reams when drilling to the reaming section 2-2, and can be reduced in diameter and taken out after drilling is completed. The structure of the under-reaming bit 5 is simple, easy to operate and can be directly taken out. The diameter of the reaming section 2-2 is 0.1 times larger than the diameter of the standard section 2-1. Taking the 2m steel pipe pile 2 as an example, the diameter of the reaming section 2-2 is 20 cm larger than the diameter of the standard section 2-1 of the steel pipe pile 2. The construction of the steel pipe pile 2 takes 3 to 5 hours, and the solidifying slurry takes 24 hours to solidify. Therefore, the construction of the present invention can be fully implemented and good technical effects can be obtained.

[0035] Under the coral reef geological conditions, the under-reaming bit 5 is placed at the bottom of the steel pipe pile 2 through the drill pipe 4, and under-reaming drilling is carried out. The hole-forming diameter is slightly larger than the diameter of the standard section 2-1 of the steel pipe pile and slightly smaller than the diameter of the reaming section 2-2. During the drilling process, the solidifying slurry is injected into the hole through the drill pipe 4. The rotating and stirring action of the under-reaming bit 5 mixes the solidifying slurry and the coral reef sand evenly, and flows to the outside of the steel pipe pile 2 through the openings 2-3 at the bottom and side of the steel pipe pile 2. After the construction is completed, both the inside and outside of the steel pipe pile 2 are wrapped by the mixture of the solidifying slurry and the coral reef sand, and the side friction resistance of the steel pipe pile 2 can be improved after coagulation.

[0036] As Figure 4 and Figure 5As shown in the figure, in a preferred embodiment of the in-situ mixing steel pipe pile construction system applied to coral reef geology of the present application, the under-reaming bit 5 includes: a hydraulic telescopic rod 5-2, which is fixedly connected to the drill pipe 4, and the bottom end of the variable diameter rod 5-1 of the hydraulic telescopic rod 5-2 is connected to the drill bit body 5-6; a fixing member 5-3, which is fixedly sleeved on the hydraulic telescopic rod 5-2; a pair of reaming rods 5-4, which are symmetrically located on both sides of the hydraulic telescopic rod 5-2, and the upper end of the reaming rod 5-4 is hinged to the fixing member 5-3; a pair of connecting rods 5-5, which are also symmetrically located on both sides of the hydraulic telescopic rod 5-2, the upper end of the connecting rod 5-5 is hinged to the reaming rod 5-4, and the lower end of the connecting rod 5-5 is hinged to the drill bit body 5-6.

[0037] In the above technical solution, the under-reaming of the under-reaming bit 5 is realized by the telescopic movement of the hydraulic telescopic rod 5-2. Specifically, it is realized by the up and down telescopic movement of the variable diameter rod 5-1 inside the hydraulic telescopic rod 5-2, and its telescopic movement is controlled by a controller connected to the construction ground through a circuit. When the variable diameter rod 5-1 moves up and down, it drives a pair of connecting rods 5-5 to expand and contract in and out, thereby driving a pair of reaming rods 5-4 to expand and contract in and out, realizing the expansion and contraction of the under-reaming bit 5.

[0038] The specific construction effects of the present invention are as follows:

[0039] Side friction resistance problem: In coral reef geology, when directly driving steel pipe piles, the side friction resistance is about 0 - 20 kPa. After adopting this process, the side friction resistance is 100 - 200 KPa.

[0040] In terms of vertical bearing capacity: Taking a steel pipe pile with a diameter of 1 m and a height of 20 m as an example, when driving 20 m into a certain coral reef formation and calculating, when driving with a traditional pile driving boat, its ultimate bearing capacity is about 2400 kN. After forming a pile using this process, the bearing capacity is 7500 kN.

[0041] In terms of construction efficiency: The traditional steel pipe pile driving takes 40 minutes, while this process takes 5 hours, and the bored cast-in-place pile takes 3 days.

[0042] Although the embodiments of the present invention have been disclosed as above, it is not limited to only the applications listed in the description and embodiments. It can be fully applied to various fields suitable for the present invention. For those familiar with the field, additional modifications can be easily made. Therefore, without departing from the general concept defined by the claims and the equivalent scope, the present invention is not limited to the specific details and the illustrated and described examples here.

Claims

1. Construction method of in-situ mixing steel pipe pile construction system applied to coral reef geology Characterized in that The in-situ mixing steel pipe pile construction system applied to coral reef geology includes Steel pipe piles, which are fixed at the designed positions by pile drivers. The steel pipe piles include an integrally formed upper standard section and a lower enlarged diameter section. Multiple openings are provided on the side of the steel pipe piles Rotary power device, which is installed on the upper part of the steel pipe pile. The rotary power device is connected with a drill pipe, which is located inside the steel pipe pile. The drill pipe is a hollow rod Grouting pipeline, one end of which is communicated with the drill pipe, and the other end of the grouting pipeline is connected with an external grouting device Under-reaming bit, which is connected to the bottom of the drill pipe and does not interfere with the internal communication of the bottom of the drill pipe with the steel pipe pile The construction steps are as follows Step 1: Measurement and positioning. Install the steel pipe pile at the designed position and fix it by a pile driver. The steel pipe pile enters the soil under its own weight for a certain part. At the same time, prepare the solidifying slurry and connect the grouting pipeline Step 2: Install the rotary power device on the upper part of the steel pipe pile. Lower the under-reaming bit into the steel pipe pile through the drill pipe and drill a hole Step 3: When the under-reaming bit drills to the enlarged diameter section at the bottom of the steel pipe pile, expand the under-reaming bit and continue drilling. The hole diameter is slightly larger than the pile diameter of the standard section of the steel pipe pile and slightly smaller than the pile diameter of the enlarged diameter section. During the process of drilling the hole, always inject the solidifying slurry into the bottom of the hole through the drill pipe, and drive the rotation and stirring of the under-reaming bit through the rotation of the drill pipe to mix evenly with the coral reef sand Step 4: After drilling to a certain depth, the bottom of the steel pipe pile will be basically hollow. Therefore, the steel pipe pile will continue to enter the soil under its own weight, and the solidifying slurry-coral reef sand mixture fills the inside and outside of the standard section through the openings on the steel pipe pile Step 5: Drill to the designed bottom elevation, continue to inject the solidifying slurry and rotate the under-reaming bit, stir for a period of time until the end of the steel pipe pile is densely grouted. Finally, reduce the diameter of the under-reaming bit and pull it out. After waiting for the solidifying slurry-coral reef sand mixture to coagulate and complete the curing, complete the construction of the in-situ mixing steel pipe pile 2. The construction method of the in-situ mixing steel pipe pile construction system applied to coral reef geology as described in claim 1 Characterized in that The diameter of the enlarged diameter section is more than 0.1 times the diameter of the standard section 3. The construction method of the in-situ mixing steel pipe pile construction system applied to coral reef geology as described in claim 1 Characterized in that The under-reaming bit includes Hydraulic telescopic rod, which is fixedly connected to the drill pipe. The bottom end of the variable diameter rod of the hydraulic telescopic rod is connected to the drill bit body Fixing piece, which is fixedly sleeved on the hydraulic telescopic rod A pair of expanding rods, which are symmetrically located on both sides of the hydraulic telescopic rod. The upper end of the expanding rod is hinged to the fixing piece A pair of connecting rods, which are also symmetrically located on both sides of the hydraulic telescopic rod. The upper end of the connecting rod is hinged to the expanding rod, and the lower end of the connecting rod is hinged to the drill bit body 4. The construction method of the in-situ mixing steel pipe pile construction system applied to coral reef geology as described in claim 1 Characterized in that Multiple small holes communicating with the inside of the steel pipe pile are provided on the side of the bottom of the drill pipe 5. The construction method of the in-situ mixing steel pipe pile construction system applied to coral reef geology as described in claim 3 Characterized in that The under-reamed diameter of the under-reaming bit is slightly smaller than the diameter of the reaming section and slightly larger than the diameter of the standard section.

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