A method for driving precast piles by drilling and implanting.

Abstract

This invention provides a precast pile drilling and installation method. The integrated platform at the borehole opening is a steel composite structure, serving multiple functions including positioning and adjustment, temporary fixing of the precast pile, and support for the concrete pouring guide pipe. A clamping device is installed during pile driving to fix the precast pipe pile and for splicing piles. The clamping device is removed before concrete pouring. The support point of this structure is the surrounding soil, which is fixed using driven steel piles. This method cleverly combines mature technologies, does not involve major hazards during construction, and uses conventional machinery and equipment, reducing construction safety risks. Compared to bored pile construction, this method of drilling and installing piles first, followed by grouting, can reduce costs and shorten the construction period. It has a wide range of applications, and is suitable for situations where the geology is relatively hard, contains gravel layers, or the bearing stratum is rock, making it difficult to drive or press precast piles.

Description

Technical Field

[0001] This invention relates to the technical field of precast pile driving construction in civil engineering, and specifically to a method for driving precast piles by drilling and implanting them. Background Technology

[0002] Common methods for driving precast piles include hammer driving, vibration driving, pile driving, and bored pile driving, each suitable for different geological conditions. Bored pile driving is primarily used when the geology is relatively hard, contains gravel layers, or the bearing stratum is rock, making it difficult to drive the precast pile. The conventional approach is to first drill a hole (with a diameter larger than the pile diameter), then fill the hole with a certain amount of cement mortar, cement-soil, or fine aggregate concrete, and finally drive the precast pile into place. Simultaneously, the filler material is squeezed into the voids around the pile to form a dense structure. However, this method has the following problems: the strength and durability of cement mortar and cement-soil are slightly weaker than concrete, making them unsuitable when high pile side friction resistance is required; when using fine aggregate concrete, if driving is delayed or unexpectedly interrupted, the concrete filler material is prone to hardening or coarse aggregate may accumulate at the bottom, preventing the precast pile from sinking to the correct position; using retarders to control the concrete's strength setting time also increases the turnaround time for construction equipment and the interval between adjacent holes.

[0003] There is also a technique of first driving precast piles, then pouring crushed stone from the borehole to fill the pile side, and finally grouting to fill the gaps. However, the disadvantage is that pouring crushed stone from the top can easily block the narrow space on the pile side, resulting in an empty and loose pile; it can also easily cause mud and other debris from the borehole wall to get into the crushed stone, affecting the structure of the pile side, and in severe cases, causing the pile side to "break". Summary of the Invention

[0004] The main objective of this invention is to provide a method for driving precast piles by drilling and implanting them, thereby solving the problems mentioned in the background art.

[0005] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows: The specific steps are as follows:

[0006] S1. Measure and mark out the pile driving positions according to the design, and after the site is leveled, install temporary steel casings for drilling.

[0007] S2. Based on the geological survey, select appropriate drilling equipment, carry out mud-wall drilling to form holes until the precast piles are driven to the designed position, and then clean the holes.

[0008] S3. After removing the drilling equipment, set up an integrated platform at the borehole opening;

[0009] S4. Once the pile driving equipment is in place, the precast piles are driven from below. When splicing the piles, the already driven precast piles are temporarily fixed on the clamps of the integrated platform. After the splicing of the precast piles is completed, the piles continue to be driven down. This process is repeated until the piles are driven to the bottom of the hole. Then, the piles are hammered or driven down to sink the precast piles by 30-50cm. The precast piles are temporarily fixed by using the limiting steel plate of the integrated platform and the wedge rings.

[0010] S5. Two concrete guide pipes are symmetrically installed along the precast pile body, and the top of the guide pipes are supported by a supporting collar and placed on the limiting steel plate of the integrated platform.

[0011] S6. A large hopper with double discharge ports is used to fill a certain amount of sealant, and then concrete pipes are used to seal the bottom of the hole with concrete at the same time to flush up the sediment at the bottom of the hole.

[0012] S7. Continue pouring underwater concrete, using lifting equipment and concrete tremie pipes to pour simultaneously. During the pouring process, remove the concrete tremie pipes at the same time. The bottom end of the tremie pipe section is 2-6m below the concrete surface until the design elevation is reached, and then remove the concrete tremie pipes.

[0013] S8. After removing the concrete guide pipe, keep the precast pile integrated platform stationary for 1 to 3 hours before dismantling the integrated platform and removing the temporary steel casing using lifting equipment.

[0014] In the preferred embodiment, the borehole diameter in S2 is larger than the precast pile diameter, and the remaining space can ensure the smooth lowering of the concrete guide pipe without contacting the borehole wall.

[0015] In the preferred embodiment, the integrated platform for the borehole in S3 is a steel composite structure, and a clamp is provided during pile driving to fix the precast pile and the spliced ​​precast pile.

[0016] Before pouring concrete, the clamps are removed. The support points of the integrated platform are the surrounding soil, which is fixed by driven steel piles.

[0017] In the preferred embodiment, the joint filler in S6 is fine aggregate concrete with good fluidity.

[0018] In the preferred embodiment, symmetrically setting two concrete guide pipes can prevent the sediment from being completely flushed up during the bottom sealing process and the concrete from flowing unevenly during the pouring process.

[0019] In the preferred embodiment, two concrete guide pipes are used for sealing and pouring at the same time, and a large hopper with double discharge ports is used for material discharge.

[0020] The bottom sealing and pouring are carried out alternately in equal amounts to ensure that the amount of concrete in each alternation is equal. Each time the concrete surface rises by 3 to 5 meters during each alternation, the concrete guide pipes are also removed alternately according to the pouring height to ensure that the concrete on both sides of the two concrete guide pipes is evenly aligned.

[0021] In the preferred scheme, the time for dismantling the integrated platform and removing the temporary steel casing in S8 should be determined according to the actual site conditions, based on the premise that the concrete has initially set to ensure that the precast pipe piles are not shaken, and that they are not yet completely bonded to the temporary steel casing so as not to affect the removal.

[0022] In the preferred embodiment, an early-strength agent is added to the concrete to accelerate the turnover cycle of the temporary steel casing and the integrated platform, as well as the construction progress of adjacent holes.

[0023] This invention provides a method for driving precast piles by drilling and implanting, with the following advantages:

[0024] 1. Safety: This method combines mature technologies in a clever way, and the construction process does not involve major hazard sources. The machinery and equipment used are also conventional, which reduces the construction safety risks.

[0025] 2. Economy: Compared with bored pile construction, the method of drilling and planting piles first and then filling the gaps can reduce costs and shorten the construction period.

[0026] 3. Convenience: The tools, equipment and materials used in this method are all relatively conventional, and the construction process is also easy to operate;

[0027] 4. It has a wide range of applications. When the geology is relatively hard, contains gravel layers or the bearing layer is rock, and it is difficult to drive or press the precast piles, this implantation method can be used for construction, and it has good applicability. Attached Figure Description

[0028] The present invention will be further described below with reference to the accompanying drawings and embodiments:

[0029] Figure 1 This is a schematic diagram of the temporary steel casing installation according to the present invention;

[0030] Figure 2 This is a schematic diagram of the drilling process of the present invention;

[0031] Figure 3 This is a schematic diagram of the sinking of the first precast pile of the present invention;

[0032] Figure 4 This is a schematic diagram of the sinking of the precast piles of the present invention;

[0033] Figure 5 This is a schematic diagram of the installation of the concrete conduit of the present invention;

[0034] Figure 6 This is a schematic diagram of concrete pouring according to the present invention;

[0035] Figure 7 This is a schematic diagram of the completed casting process of the present invention;

[0036] Figure 8 This is a schematic diagram of the dismantling of the present invention;

[0037] Figure 9 These are front and top views of the integrated platform installation of this invention;

[0038] Figure 10 These are front and top views of the integrated platform installation during concrete pouring according to the present invention;

[0039] In the diagram: 1. Temporary steel casing; 2. Drilling equipment; 3. Hole; 4. Pile driving equipment; 5. Integrated platform; 5. Main steel frame; 501. Limiting steel plate; 502. Pillar beam; 503. Steel pile; 504. Hoop; 505. Precast pile; 6. Sinking precast pile; 601. Spliced ​​precast pile; 602. Sinking precast pile; 603. Supporting collar; 7. Concrete guide pipe; 8. Small hopper at the top of the guide pipe; 801. Guide pipe section; 802. Large hopper with double discharge ports; 9. Lifting equipment; 10. Concrete mixer truck; 11. Detailed Implementation

[0040] Example 1

[0041] like Figures 1-10 As shown, a method for driving precast piles by drilling and embedding is described. The method involves measuring and setting out the designed pile driving position, and then installing a temporary steel casing for drilling after the site is leveled.

[0042] Based on the geological survey, select appropriate drilling equipment such as rotary drilling rig, impact drilling rig, auger drilling rig or rotary drilling rig 2, and carry out mud wall drilling to form holes 3. The hole diameter is 25~35cm larger than the precast pile diameter 6 until the precast pile is driven to the designed position, and then clean the hole.

[0043] After removing the drilling equipment 2, an integrated platform 5 is set up at the borehole opening for lowering the precast pile 6, limiting and fixing the precast pile 6, and for subsequent concrete pouring.

[0044] Once the pile driving equipment 4 is in place, the precast pile 6 is lowered and driven. During the pile splicing, the pipe pile is temporarily fixed on the clamp 505 of the integrated platform 5. After the splicing is completed, the pile continues to be lowered. After it is lowered to the bottom of the hole, the precast pile 6 is further hammered or pressed to sink it by 30-50cm. The precast pile 6 is temporarily fixed using the integrated platform 5 in combination with the wedge ring.

[0045] Two concrete guide pipes 8 are symmetrically arranged along the precast pile 6, and the top of the guide pipes are supported on the integrated platform 5 using a supporting collar 7.

[0046] A large hopper is used to fill a certain amount of fine aggregate concrete (enough to ensure that the bottom of the guide pipe is buried more than 1m below the concrete after sealing). Then, two concrete guide pipes are used simultaneously to seal the bottom of the hole and flush up the sediment at the bottom.

[0047] Continue pouring underwater concrete (with an early-strength agent added), pouring with two guide pipes simultaneously (or pouring in equal amounts alternately, with an alternating height of 3-5m). During the pouring process, remove the guide pipes simultaneously (or remove them alternately with equal lengths). The bottom of the guide pipes should be 2-6m below the concrete surface until the design elevation is reached, and then remove the guide pipes.

[0048] Keep the temporary fixing device of the precast pile 6 still for 1 to 3 hours (around the initial setting period of the concrete), then remove the temporary fixing device of the precast pile 6 and pull out the temporary steel casing 1. During the pulling process, it is advisable to minimize the disturbance to the concrete.

[0049] Preferably, the diameter of borehole 3 should be larger than the diameter of precast pile 6, with the remaining space ensuring the smooth lowering of the concrete guide pipe without contacting the borehole wall; the diameter of the guide pipe should be 125~150mm, which can ensure the normal flow of concrete and the smooth lowering to the bottom of the borehole.

[0050] Preferably, after the precast pile 6 is lowered to the bottom of the hole, it is continued to be hammered or driven into a small displacement. This is mainly to prevent the soil at the bottom of the hole from being disturbed during the drilling process, which would cause the bottom of the hole to be loose. Continuing to hammer or drive the pile ensures that the pile is driven into place and stable.

[0051] Preferably, the integrated platform 5 of the orifice is a steel composite structure, which has the functions of limiting adjustment, temporarily fixing the precast pile 6, and supporting the concrete guide pipe 8 later. When driving the pile, a clamp device is provided to fix the precast pipe pile 6 and splice the pile. The clamp 505 is removed before pouring concrete. The support point of this structure is the surrounding soil, which is fixed by driving steel piles.

[0052] Preferably, fine aggregate concrete with good fluidity should be used as the joint filler.

[0053] Preferably, the purpose of symmetrically setting two guide pipes is to solve the problem of poor flowability of concrete in the narrow space around the pile, and to prevent the sediment from being completely flushed up during the bottom sealing and the uneven flow of concrete during the pouring process.

[0054] Preferably, when sealing and pouring the bottom of the two guide pipes at the same time, a large hopper with double discharge ports should be used for material discharge; if sealing and pouring are carried out alternately with equal amounts, it is necessary to ensure that the amount of concrete in the alternation is equal, and the concrete surface should rise by 3 to 5 meters each time the concrete is poured. The guide pipes should also be removed alternately according to the pouring height to ensure that the concrete on the sides of the two guide pipes is evenly distributed.

[0055] Preferably, the time for dismantling the integrated platform 5 and removing the temporary steel casing 1 should be determined according to the actual site conditions, based on the condition that the concrete has initially set to ensure that the precast pipe piles are not shaken and have not yet completely adhered to the casing to avoid affecting the removal.

[0056] Preferably, early-strength agents are added to the concrete to accelerate the turnover cycle of the steel casing 1 and the integrated structure, as well as the construction progress of adjacent holes (adjacent holes need to be constructed by "skipping piles" to reduce disturbance, and generally can only be constructed after the adjacent piles are stable, and construction can proceed closely).

[0057] Example 2

[0058] like Figures 1-10 As shown in Example 1, the specific construction steps are as follows:

[0059] 1) Measure and mark out the pile driving positions according to the design, and after leveling the site, install temporary steel casings for drilling.

[0060] 2) Based on the geological survey, select appropriate drilling equipment such as rotary drilling rig, impact drilling rig, auger drilling rig or rotary drilling rig 2, and carry out mud wall drilling to form holes 3 until the precast piles are driven to the designed position and the holes are cleaned.

[0061] 3) After removing the drilling equipment 2, an integrated platform 5 is set up at the borehole opening for the lowering, limiting, and fixing of the precast piles, as well as for the subsequent pouring of concrete.

[0062] 4) Once the pile driving equipment 4 is in place, the precast pile 6 is lowered and driven. When splicing the pile, the pipe pile 601 is temporarily fixed on the clamp 505 of the integrated platform 5. After the splicing of the precast pile 602 is completed, it continues to be lowered. This process is repeated until the pile is lowered to the bottom of the hole. Then, hammering or pressing is continued to make the precast pile sink 30-50cm. The precast pile is temporarily fixed by using the limiting steel plate 502 of the integrated platform 5 to insert a wedge ring.

[0063] 5) Two concrete pouring guide pipes 8 are symmetrically set along the precast pile body, and the top of the guide pipe is placed on the limiting steel plate 502 of the integrated platform 5 using the supporting collar 7.

[0064] 6) Use a double-outlet large hopper 9 to fill a certain amount of fine stone concrete (enough to bury the bottom of the guide pipe more than 1m below the concrete after sealing), and then use the guide pipe 8 to seal the bottom of the hole with concrete at the same time to flush up the sediment at the bottom of the hole.

[0065] 7) Continue pouring underwater concrete, using the lifting equipment 10 and the guide pipe 8 to pour simultaneously. During the pouring process, the guide pipe 8 is removed simultaneously. The bottom end of the guide pipe section 802 is located 2-6m below the concrete surface until the design elevation is reached, and then the guide pipe 8 is removed.

[0066] 8) After removing the guide pipe 8, keep the precast pile 6 integrated platform 5 stationary for 1 to 3 hours (around the initial setting time of the concrete), then dismantle the integrated platform and use the lifting equipment 10 to remove the temporary steel casing 1.

[0067] The above embodiments are merely preferred technical solutions of the present invention and should not be considered as limitations on the present invention. The scope of protection of the present invention should be limited to the technical solutions described in the claims, including equivalent substitutions of the technical features described in the claims. That is, equivalent substitutions and improvements within this scope are also within the scope of protection of the present invention.

Claims

1. A method for driving precast piles by drilling and embedding, the method comprising the following specific steps: S1. Measure and lay out the pile driving position according to the design. After the site is leveled, install temporary steel casing for drilling (1). S2. Based on the geological survey, select appropriate drilling equipment (2) to carry out mud wall drilling and hole formation (3) until the precast pile driving design position is reached, and then clean the hole (3). S3. After removing the drilling equipment (2), set up an integrated platform (5) at the borehole opening. S4. The pile driving equipment (4) is in place, and the precast pile (6) is driven. When the pile is connected, the precast pile (601) that has been driven is temporarily fixed on the clamp (505) of the integrated platform (5). After the precast pile (602) is connected, it continues to be lowered. The cycle continues until it is lowered to the bottom of the hole. Then, the hammer or pile is driven to make the precast pile (6) sink 30~50cm. The precast pile (6) is temporarily fixed by the wedge ring of the limiting steel plate (502) of the integrated platform (5). S5. Two concrete guide pipes (8) are symmetrically arranged along the precast pile (6) and the top of the guide pipes are placed on the limiting steel plate (502) of the integrated platform (5) using the supporting collar (7). S6. Use a double-outlet large hopper (9) to fill a certain amount of sealant, and then use concrete guide pipes (8) to seal the bottom of the hole with concrete at the same time to flush up the sediment at the bottom of the hole. S7. Continue to pour underwater concrete. Use the lifting equipment (10) and the concrete pipe (8) to pour at the same time. During the pouring process, remove the concrete pipe (8) at the same time. The bottom end of the pipe section (802) is 2~6m below the concrete surface until the design elevation is reached and the concrete pipe (8) is removed. S8. After removing the concrete guide pipe (8), keep the precast pile (6) integrated platform (5) still for 1h~3h, then dismantle the integrated platform (5) and use the lifting equipment (10) to remove the temporary steel casing (1).

2. The pile driving construction method for precast pile drilling and implantation according to claim 1, characterized in that: S2 The diameter of the borehole is larger than that of the precast pile (6), and the remaining space can ensure that the concrete guide pipe (8) is lowered smoothly without touching the borehole wall.

3. The pile driving construction method for precast pile drilling and implantation according to claim 1, characterized in that: The integrated platform (5) in S3 is a steel composite structure. When driving the pile, it is equipped with a clamp (505) to fix the precast pile (6) and the splicing precast pile (602). Before pouring concrete, remove the clamps (505). The support point of the integrated platform (5) is the surrounding soil, which is fixed by driving in steel piles (504).

4. The pile driving construction method for precast pile drilling and implantation according to claim 1, characterized in that: The joint filler in S6 uses fine aggregate concrete with good fluidity.

5. The pile driving construction method for precast pile drilling and implantation according to claim 1, characterized in that: The timing of removing the integrated platform (5) and the temporary steel casing (1) in S8 should be determined according to the actual site conditions, based on the premise that the concrete has initially set and can ensure that the precast pipe pile (6) is not shaken, and that it has not yet completely adhered to the temporary steel casing (1) and will not affect the removal.

6. The pile driving construction method for precast pile drilling and implantation according to claim 1, characterized in that: Adding an early-strength agent to the concrete accelerates the turnover cycle of the temporary steel casing (1) and the integrated platform (5) as well as the construction progress of adjacent holes.

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