High-strength bare rock bored steel pipe piles and their construction method

Abstract

This invention provides a high-strength bare rock pre-drilled anchored steel pipe pile and its construction method. By pre-pouring concrete at the bottom of the steel pipe pile and arranging multiple grouting pipes, the floating problem of the steel pipe pile during sidewall grouting is effectively prevented. The overall operation is simple, ensuring the quality of grouting construction and improving construction efficiency by completing the grouting in one go. By using underwater drilling and blasting to assist in hole formation, the problem of difficulty in inserting steel pipe piles into inclined rock surfaces is effectively solved, improving construction efficiency, shortening the construction period, and improving the overall construction quality of the steel pipe pile while ensuring safety and reliability. By adding a guide steel pipe at the tail of the drill bit and installing a spiral strip on the outer wall of the guide steel pipe, the construction accuracy of the steel pipe pile is improved, while avoiding wear between the lower steel pipe and the inner wall of the steel pipe pile, so that the construction quality of the steel pipe pile meets the design and specification requirements.

Description

Technical Field

[0001] This invention relates to the field of steel pipe pile construction in marine environments, and in particular to high-strength bare rock pre-drilled anchored steel pipe piles and construction methods. Background Technology

[0002] With the increasing demand for transportation, the expansion of bridge spans, and the deepening of foundation penetration into water, bridge foundation structures are evolving rapidly, from the initial caisson and well foundations to pipe pile foundations, pile foundations, and various combined foundations and special foundations. Pile foundations are widely used in my country, but their construction often faces challenges such as harsh environments and complex techniques. The highly variable environment and geological conditions of marine areas significantly impact actual construction. Currently, steel trestle bridges and steel platforms are widely used in cross-river and sea bridge projects. However, in marine areas with riverbeds covered by high-strength rock strata, traditional steel pipe pile construction methods face difficulties such as not being able to penetrate deep into the riverbed, failing to meet the requirements for pull-out bearing capacity and penetration depth, and encountering problems such as unstable foundation construction and difficulty in controlling construction precision. Therefore, research on high-strength bare rock pre-drilled anchored steel pipe piles and their construction methods is of significant practical importance. Summary of the Invention

[0003] The purpose of this invention is to provide a high-strength bare rock pre-drilled anchored steel pipe pile and construction method that solves the above-mentioned technical problems.

[0004] To solve the above-mentioned technical problems, the present invention provides a construction method for high-strength bare rock pre-drilled anchored steel pipe piles, comprising the following steps:

[0005] S1. First, a steel casing is laid at the construction site to penetrate the overburden layer. The bottom of the steel casing is embedded in the rock layer. Then, before the steel pipe pile is lowered, the first grouting pipe is arranged on the outside and inside of the pile wall respectively. Concrete is pre-poured at the bottom of the steel pipe pile. Then, the steel pipe pile is lowered into the pile hole. Finally, the first grouting pipe is used to perform a one-time continuous grouting operation on the bottom reserved cavity and the void area of ​​the pile side wall.

[0006] S2. When there is a sloping rock surface in the near-shore waters, the work vessel is anchored on the water surface of the designated construction area. First, the position is measured and cored at the sloping rock surface of the external guide pipe and blasting hole. Then, the external guide pipe, PVC pipe and waterproof sealing material are installed together and lowered and fixed using the work platform on the work vessel. Next, the explosives and detonators are tied together in a string using plastic binding ropes, and a counterweight is placed at the bottom of the string of explosives. After the string of explosives is made, it is lowered into place by rope and detonating cord for blasting. Then, the drilling machine is used to continue the hole drilling.

[0007] S3. When constructing steel pipe piles underwater, a guide steel pipe is installed at the tail of the drill bit, and a spiral strip is installed on the outer wall of the guide steel pipe. Then, the drill bit is installed at the lower part of the drill rod and placed into the steel pipe pile. Finally, the drilling machine is started to carry out the hole-forming operation.

[0008] S4. When steel pipe piles are constructed in deep water and high-strength bare rock areas, firstly, a drilling rig is used to drill and core samples inside the steel pipe piles to form anchoring holes. Then, I-beams are placed into the anchoring holes as anchor bars. Next, a second grouting pipe and a sonic logging pipe are installed into the anchoring holes, and cement grout is injected into the anchoring holes until the rock surface is reached. Finally, concrete is poured into the space above the rock surface of the steel pipe piles to form a stable anchoring system of rock strata, I-beams, and steel pipe piles.

[0009] The beneficial effects of this invention are as follows:

[0010] (1) By pre-casting concrete at the bottom of the steel pipe pile and arranging multiple grouting pipes, the problem of the steel pipe pile floating during the side wall grouting construction is effectively prevented. The overall operation is simple, the grouting construction quality is guaranteed, and the one-time grouting completion improves the construction efficiency.

[0011] (2) By using underwater drilling and blasting to assist in hole formation, the problem of difficulty in inserting steel pipe piles into rock at inclined rock surfaces was effectively solved, the construction efficiency was improved, the construction period was shortened, and the overall construction quality of steel pipe piles was improved on the basis of ensuring safety and reliability.

[0012] (3) By adding a guide steel pipe at the tail of the drill bit and installing a spiral strip on the outer wall of the guide steel pipe, the accuracy of steel pipe pile construction is improved, and wear between the lower steel pipe and the inner wall of the steel pipe pile is avoided, so that the construction quality of the steel pipe pile meets the design and specification requirements.

[0013] (4) A drilling machine is used to drill cores in the steel pipe pile to form a rebar hole. After the hole is formed, an I-beam is placed in it as an anchor bar and grouting is used to solidify it. This solves the problem that the bearing capacity of the steel pipe pile is not guaranteed due to insufficient rock penetration depth. The overall system is safe and reliable, and the support stability of the steel pipe pile is enhanced. Attached Figure Description

[0014] Figure 1 Schematic diagram of the floating control technology for embedded rock-socketed steel pipe piles;

[0015] Figure 2 Schematic diagram of underwater blasting hole-forming technology on inclined rock surfaces;

[0016] Figure 3 Schematic diagram of underwater blasting explosives;

[0017] Figure 4 Schematic diagram of underwater blasting hole layout;

[0018] Figure 5 Schematic diagram of impact drilling pilot hole technology using guide steel pipe;

[0019] Figure 6 Schematic diagram of core extraction through drilling of I-beam with pilot hole inserted;

[0020] Figure 7 Schematic diagram of I-beam grouting and anchoring construction;

[0021] Figure 8 Schematic diagram of the anchoring technology for I-beams with pilot holes.

[0022] Explanation of reference numerals in the attached drawings: 1-Steel casing, 2-Steel pipe pile, 3-First grouting pipe, 4-Covering layer, 5-End plate, 6-Precast concrete, 7-Rock stratum, 8-Reserved cavity, 9-Cavity grout outlet, 10-Grouting outlet No. 1, 11-Grouting outlet No. 2, 12-Grouting outlet No. 3, 13-Grouting outlet No. 4, 14-Grouting material, 15-Water surface, 16-Working vessel, 17-Working platform, 18-Outer guide pipe, 19-Waterfront, 20-Sloping rock surface, 21-PVC pipe, 22- - Waterproof sealing material, 23- Explosives, 24- Plastic binding rope, 25- Rope, 26- Detonator, 27- Detonating cord, 28- Counterweight, 29- Steel pipe pile location, 30- Blasting hole, 31- Sealing cap, 32- Drill rod, 33- Drill bit, 34- Spiral strip, 35- Guide steel pipe, 36- Lower rock mass, 37- Water body, 38- Rock surface, 39- Rebar hole, 40- I-beam, 41- Sonic logging pipe, 42- Second grouting pipe, 43- Cement grout, 44- Concrete. Detailed Implementation

[0023] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention are within the scope of protection of the present invention.

[0024] Those skilled in the art should understand that, in the disclosure of the present invention, the terms "longitudinal", "transverse", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like to indicate orientations or positional relationships are based on the orientations or positional relationships shown in the accompanying drawings, which are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, the above terms should not be understood as limiting the present invention.

[0025] It is understood that the term "a" should be understood as "at least one" or "one or more", that is, in one embodiment, the number of an element can be one, while in another embodiment, the number of the element can be multiple, and the term "a" should not be understood as a limitation on the number.

[0026] like Figures 1-8 The present invention provides a high-strength bare rock anchored steel pipe pile with pre-drilled holes and a construction method thereof, including the following steps:

[0027] S1. First, a steel casing 1 is laid at the construction location to penetrate the overburden layer 4. The bottom of the steel casing 1 is embedded in the rock layer 7 to provide construction protection for the steel pipe pile 2. Then, before the steel pipe pile 2 is lowered, the first grouting pipe 3 is arranged on the outside and inside of the pile wall respectively, and concrete 6 is pre-poured at the bottom of the steel pipe pile 2. Then, the steel pipe pile 2 is lowered into the pile hole, and the construction position is checked and fixed. Finally, the first grouting pipe 3 is used to continuously inject grout 14 into the bottom reserved cavity 8 and the void area of ​​the pile side wall. During the initial grouting, the No. 3 grout outlet 12 is used first for continuous operation. If the pipe is blocked or the pressure is abnormal, the No. 1 grout outlet 10, No. 2 grout outlet 11, and No. 4 grout outlet 13 are immediately replaced for grouting. When the grout 14 fills the construction void and meets the requirements, the subsequent construction steps of the steel pipe pile 2 are carried out.

[0028] like Figure 1 As shown, when constructing steel pipe piles 2 on the waterfront, a steel casing 1 is first installed on the outside for protection. A 35cm high reserved cavity 8 is set at the bottom of the steel pipe pile 2, and grout outlets 9 are symmetrically set on both sides of the reserved cavity 8. Three first grouting pipes 3 are arranged on the inside of the steel pipe pile 2 and one first grouting pipe 3 is arranged on the outside. When the steel pipe pile 2 is driven into the pile, a one-time continuous grouting operation 14 is carried out on the reserved cavity 8 at the bottom and the side wall of the pile to improve the integrity between the steel pipe pile 2 and the rock stratum 7. The first grouting pipe 3 is fixed inside the steel pipe pile 2 with the help of a head plate 5.

[0029] In particular, an accelerator is appropriately added to the grout 14 during preparation, so that the grout 14 can solidify in a short time after grouting construction, reducing the impact of grout floating.

[0030] S2. When a sloping rock surface 20 appears in the waters near the shore 19, the work vessel 16 is anchored on the water surface 15 of the designated construction area. First, the location is measured and drilled using a drilling machine to core the sloping rock surface 20 at the external guide pipe 18 and the blasting hole 30. Then, the external guide pipe 18, PVC pipe 21 and waterproof sealing material 22 are installed together and temporarily fixed in the designed position using the work platform 17 on the work vessel 16. Next, the explosives 23 and detonators 26 are tied together into a string using plastic binding rope 24, and a counterweight 28 is placed at the bottom of the string of explosives 23. After the string of explosives 23 is completed, it is lowered into place using rope 25 and detonating cord 27. Finally, professional personnel carry out the blasting operation. After the site is cleared and the warning is removed, the drilling machine is used to continue the hole drilling.

[0031] like Figures 2-4As shown, when constructing steel pipe piles in the sloping rock surface 20 of the near-water shore 19, a PVC pipe 21 is placed in an outer guide tube 18, and a waterproof sealant 22 is filled into the bottom cavity of the outer guide tube 18. The outer guide tube 18 and the PVC pipe 21 are lowered and fixed using a working platform 17. Before lowering, the bottom of the PVC pipe 21 is sealed with a sealing cap 31. The dosage and operation of the underwater blasting explosive 23 are designed and constructed by professionals according to specifications to ensure safe operation. The waterproof sealant 22 not only plays a waterproof role but also uses its own weight to help the outer guide tube 18 and the PVC pipe 21 resist buoyancy.

[0032] The counterweight 28 at the bottom of the string of explosives 23 can be made from locally sourced rock cores extracted from the borehole.

[0033] S3. When constructing the steel pipe pile 2 below the water surface 15, in order to ensure construction quality and accuracy, the drill bit 33 of the drilling rig is first optimized and modified. A guide steel pipe 35 is added to the tail of the drill bit 33, and a spiral strip 34 is welded to the outer wall of the guide steel pipe 35. Then, the optimized and modified drill bit 33 is installed at the lower part of the drill rod 32, and the drill bit 32 is placed in the designated construction position inside the steel pipe pile 2. Finally, the drilling rig is started to carry out the hole-forming operation. The added guide steel pipe 35 and spiral strip 34 avoid the risk of the guide steel pipe 35 rubbing against the inside of the steel pipe pile 2 during construction, while ensuring the verticality of the pile hole.

[0034] like Figure 5 As shown, when constructing steel pipe piles 2 in the rock mass 36 below the water surface 15, a guide steel pipe 35 is added to the tail of the drill bit 33, and six spiral strips 34 are installed on the outer wall of the guide steel pipe 35 to protect the inner wall of the steel casing 2. Then, the drill bit 33 is driven by the drill rod 32 to perform hole forming operation.

[0035] During the drilling operation, the guide steel pipe 35 is always kept at least 2.5m inside the original steel pipe pile 2.

[0036] When the steel pipe pile 2 is constructed in the deep-water, high-strength bare rock area, a drilling rig is first used to drill and core samples inside the steel pipe pile 2 to form a rebar anchoring hole 39. Then, the I-beam 40 is placed into the rebar anchoring hole 39 as an anchor bar. Next, a second grouting pipe 42 and a sonic logging pipe 41 are installed into the rebar anchoring hole 39, and cement grout 43 is injected into the rebar anchoring hole 39 until the rock surface 38 is reached. The sonic logging pipe 41 is used to check and confirm the grouting quality of the rebar anchoring hole 39. Finally, when the grouting construction in the rebar anchoring hole 39 meets the requirements, concrete 44 is poured in the space above the rock surface 38 of the steel pipe pile 2 to form a stable anchoring system with the rock layer 7, the I-beam 40, and the steel pipe pile 2, thereby improving the overall stability of the steel pipe pile 2.

[0037] like Figures 6 to 8As shown, when steel pipe piles 2 are operated in a high-strength bare rock area in water, the depth of penetration into the rock layer 7 is difficult to meet the requirements. Therefore, firstly, a drilling machine is used to drill and core samples in the steel pipe pile 2 to form a rebar hole 39. Then, two I-beams 40 are placed in the rebar hole 39 as anchor bars. The overall stability is improved by the stable anchoring system formed by the rock layer 7, the I-beams 40, and the steel pipe pile 2, which resists the construction load and the load generated by the surrounding water body 37.

[0038] Among them, C30 concrete was used for the concrete pouring in the upper space of the rock surface 38 of the steel pipe pile 2.

[0039] The present invention is not limited to the above-mentioned optimal implementation mode. Anyone can derive other forms of products under the inspiration of the present invention. However, no matter what changes are made in the shape or structure, any technical solution that is the same or similar to that of the present application falls within the scope of protection of the present invention.

Claims

1. A construction method for anchoring high-strength bare rock steel pipe piles using pre-drilled holes, characterized in that... Includes the following steps: S1. First, a steel casing (1) is laid at the construction site to pass through the overburden layer (4). The bottom of the steel casing (1) is embedded in the rock layer (7). Then, before the steel pipe pile (2) is lowered, the first grouting pipe (3) is arranged on the outside and inside of the pile wall respectively, and concrete (6) is pre-poured at the bottom of the steel pipe pile (2). Then, the steel pipe pile (2) is lowered into the pile hole. Finally, the first grouting pipe (3) is used to perform a one-time continuous grouting operation (14) on the bottom reserved cavity (8) and the void area of ​​the pile side wall. S2. When a sloping rock surface (20) appears in the water near the shore (19), the work vessel (16) is anchored on the water surface (15) of the designated construction area. First, the position is measured and the core drilling operation is carried out on the sloping rock surface (20) at the external guide (18) and the blasting hole (30). Then, the external guide (18), PVC pipe (21) and waterproof sealing material (22) are installed together and lowered and fixed using the work platform (17) on the work vessel (16). Then, the explosive (23) and detonator (26) are tied together into a string using plastic binding rope (24), and a counterweight (28) is placed at the bottom of the string of explosives (23). After the string of explosives (23) is made, it is lowered into place by rope (25) and detonating cord (27) for blasting operation. Then, the drilling machine is used to continue the hole drilling construction. S3. When constructing steel pipe piles (2) below the water surface (15), a guide steel pipe (35) is installed at the tail of the drill bit (33), and a spiral strip (34) is installed on the outer wall of the guide steel pipe (35). Then, the drill bit (33) is installed at the lower part of the drill rod (32), and the drill bit (33) is placed into the steel pipe pile (2). Finally, the drilling machine is started to carry out hole-forming operations. S4. When the steel pipe pile (2) is constructed to the deep water high-strength bare rock area, the drilling machine is first used to drill and core the steel pipe pile (2) to form a rebar hole (39). Then, the I-beam (40) is placed into the rebar hole (39) as an anchor bar. Next, the second grouting pipe (42) and the sonic logging pipe (41) are installed into the rebar hole (39), and cement grout (43) is injected into the rebar hole (39) until the rock surface (38) is reached. Finally, concrete (44) is poured in the space above the rock surface (38) of the steel pipe pile (2) so that the rock layer (7), the I-beam (40) and the steel pipe pile (2) form a stable anchoring system.

2. The construction method for high-strength bare rock pre-drilled anchored steel pipe piles according to claim 1, characterized in that: In step S1, during the initial grouting, the No. 3 grout outlet (12) is used first for continuous operation. If the pipe is blocked or the pressure is abnormal, the No. 1 grout outlet (10), No. 2 grout outlet (11), and No. 4 grout outlet (13) are replaced for grouting operation.

3. The construction method for high-strength bare rock pre-drilled anchored steel pipe piles according to claim 1, characterized in that: In step S1, a reserved cavity (8) is provided at the bottom of the steel pipe pile (2), and grout outlets (9) are symmetrically provided on both sides of the reserved cavity (8). The steel pipe pile (2) is connected to the first grouting pipe (3) through the end cap plate (5).

4. The construction method for high-strength bare rock pre-drilled anchored steel pipe piles according to claim 1, characterized in that: A quick-setting agent is added during the preparation of the slurry (14).

5. The construction method for high-strength bare rock pre-drilled anchored steel pipe piles according to claim 1, characterized in that: In step S2, the PVC pipe (21) is placed in the outer conduit (18), and waterproof sealing material (22) is filled into the cavity at the bottom of the outer conduit (18); the bottom of the PVC pipe (21) is sealed with a sealing cap (31) before it is lowered.

6. The construction method for high-strength bare rock pre-drilled anchored steel pipe piles according to claim 1, characterized in that: In step S3, steel pipe piles (2) are constructed in the rock mass (36) below the water surface (15), and six spiral strips (34) are installed on the outer wall of the guide steel pipe (35) to protect the inner wall of the steel casing (1).

7. The construction method for high-strength bare rock pre-drilled anchored steel pipe piles according to claim 1, characterized in that: In step S4, C30 concrete is used for the concrete (44).

8. A high-strength bare rock pre-drilled rebar anchoring steel pipe pile, characterized in that: The high-strength bare rock pre-drilled anchored steel pipe pile is obtained by the construction method according to any one of claims 1-7.

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