End porous type expanded head full-section grouting screw pile and pile forming method thereof

Abstract

The invention discloses a full-section grouting screw pile with a porous end and an expanded head and a pile forming method of the full-section grouting screw pile. The device comprises an outer sleeve with holes in the whole section and an inner drill rod with multiple holes in the end. The full-section trepanning outer sleeve comprises a pile body, and internal threads are arranged in the pile body. The end porous type inner drill rod comprises a rod body and a pile head, the pile head is an inverted cone and is connected to the lower end of the rod body, external threads are arranged on the outer side of the rod body, and the whole-section perforated outer sleeve is connected with the end porous type inner drill rod through the threads; a grouting channel is arranged in the whole-section opening outer sleeve and the end porous inner drill rod, and a plurality of grouting outlets connected to the grouting channel are formed in the outer surface of the pile body and the outer surface of the pile head. The movement of the inner drill rod in the outer sleeve is controlled through screw-in of the threads, and operation is easy and convenient; convex nozzles on the surface of the outer sleeve can increase the surface friction coefficient; the anchoring length is effectively increased through the depth of the inner drill rod, and the bearing performance is improved; and through secondary grouting, a tentacle is used for going deep into the soil body for grouting, and the wrapping effect of the cement paste is enhanced.

Description

Technical Field

[0001] The invention belongs to the technical field of grouting screw piles, and in particular relates to a full-section grouting screw pile with a porous end enlarged head and a pile forming method thereof. Background Art

[0002] China has rich marine resources, but there is a wide distribution of marine soft clay in the coastal areas of my country, which has the characteristics of high water content, low strength, large compression settlement, and poor stability, which brings great challenges to the construction of marine engineering. The spiral pile is a special-shaped pile, which is a variable-section pile formed by connecting a number of spiral blades with a central axis. Compared with traditional piles, it has the advantages of fast pile formation, green environmental protection, and material saving. In order to cope with the poor geological conditions in coastal areas, spiral piles are widely used in offshore and coastal marine engineering construction. However, the bearing capacity of traditional spiral steel piles is limited, and the effect of simply increasing the diameter of the steel pipe, expanding the diameter of the spiral blade, and increasing the thickness of the blade is also limited and will increase the cost. In addition, due to the small soil pressure on the upper part of the pile body, the spiral pile will cause shaking and produce gaps during the construction process, and cannot exert its full bearing capacity. Moreover, the steel pipe is exposed in the marine soft soil and is easily eroded by seawater. The grouting screw pile is a further upgrade of the traditional screw pile, which combines the technology of drilling and grouting with the screw pile. The screw pile can spray slurry to the surrounding areas through small holes during the process of being screwed into the soil. The sprayed slurry can form a spiral cement mortar to wrap the pile body and fill the gaps generated during the screw pile's twisting process. It can increase the bearing capacity of the screw pile while protecting the pile shaft steel pipe from corrosion by sulfate ions and chloride ions.

[0003] With the rapid development of marine infrastructure engineering, higher requirements are placed on the bearing capacity of screw piles. In order to further enhance the pull-out resistance of grouting screw piles and make them more effective in engineering applications, it is necessary to propose a new enlarged head grouting screw pile. Summary of the invention

[0004] The purpose of the present invention is to solve the problems raised in the background technology, and to propose a full-section grouting spiral pile with a porous end enlarged head and a pile forming method thereof. The advantages are that the grouting range is expanded at the pile head by the secondary grouting method, the bearing capacity of the spiral pile is effectively enhanced, and the requirements and needs of modern marine infrastructure projects can be better met. The difference between the present invention and the traditional grouting spiral pile is that after the first grouting, the pile head can extend tentacles with small grouting holes distributed thereon, and the grouting holes on these tentacles can spray slurry outward for the second grouting, thereby increasing the slurry around the pile head, forming a coarser cement mortar solidified body at the pile head, and improving the bearing capacity of the spiral pile.

[0005] In order to achieve the purpose of the present invention, the present invention discloses a full-section grouting spiral pile with a porous enlarged head at the end, comprising a full-section perforated outer sleeve and a porous inner drill rod at the end; the full-section perforated outer sleeve comprises a pile body, and an internal thread is arranged inside the pile body; the porous inner drill rod at the end comprises a rod body and a pile head, the pile head is an inverted cone, connected to the lower end of the rod body, an external thread is arranged on the outer side of the rod body, and the full-section perforated outer sleeve and the porous inner drill rod at the end are connected by threads; grouting channels are arranged inside the full-section perforated outer sleeve and the porous inner drill rod at the end, and a plurality of grouting outlets connected to the grouting channels are arranged on the outer surfaces of the pile body and the pile head.

[0006] Furthermore, a plurality of grouting nozzles are arranged on the outer surface of the pile body, a first internal grouting channel is arranged in the pipe wall of the pile body, a grouting port is arranged at the upper end of the first internal grouting channel, and the lower end of the first internal grouting channel is connected to the plurality of grouting nozzles.

[0007] Furthermore, a plurality of spiral blades are welded on the outer surfaces of the pile body and the pile head.

[0008] Furthermore, a plurality of tentacles for spraying slurry are provided through the pile head, a second internal grouting channel is provided inside the shaft, a grouting port is provided at the upper end of the second internal grouting channel, and the lower end of the second internal grouting channel is connected to the plurality of tentacles.

[0009] Furthermore, there are circular holes on the surface of the pile head, and the tentacles are installed in the circular holes on the surface of the pile head through buckles; the tentacles are two small tubes nested in each other, which can be freely extended and retracted to lengthen or shorten the tentacles; and a plurality of small holes are provided on the surface of the tentacles as micro grouting holes.

[0010] Furthermore, the length of the shaft is longer than the pile shaft, and the upper part of the shaft extends out of the pile shaft.

[0011] Furthermore, the second internal grouting channel gradually narrows from top to bottom.

[0012] Furthermore, a grouting port provided at an upper end of the first internal grouting channel or the second internal grouting channel is connected to an external grouting device.

[0013] In order to achieve the purpose of the present invention, the present invention also discloses a method for forming a spiral pile with a multi-hole end enlarged head and a full-section grouting, comprising the following steps:

[0014] S1. The outer casing with full opening holes is tightly connected with the multi-hole inner drill rod at the end through threads. During construction, the spiral pile is vertically lifted with the pile head facing downward, and then slowly drilled into the soil along the direction of the spiral blade until the entire length of the outer casing with full opening holes enters the soil;

[0015] S2, the first grouting, the grouting equipment is connected to the grouting port at the upper end of the outer casing with full-section openings, and the high water-cement ratio cement slurry prepared in advance is injected into the grouting port under high pressure, and the cement slurry is ejected outward through the grouting protrusion along the first internal grouting channel, penetrates into the surrounding soil, and combines with the soil;

[0016] S3. The piling equipment is connected to the inner drill rod and the second piling begins. The porous inner drill rod at the end goes down along the thread and goes deeper into the soil along the spiral blade at the pile head.

[0017] S4. After the end porous inner drill rod reaches the maximum depth, the second grouting is carried out. The grouting equipment is connected to the upper grouting port of the end porous inner drill rod, and the high water-cement ratio cement slurry prepared in advance is injected into the grouting port under high pressure; when entering the second internal grouting channel in the inner drill rod, it becomes narrower and narrower as it goes downwards. Due to the narrow tube effect, the flow rate of the cement slurry gradually increases, and when it flows to the tentacles at the pile head, it has achieved a relatively high flow rate, which can flush the tentacles out of the pile head and penetrate into the surrounding soil; at the same time, the high-flow cement slurry is ejected outward from the micro-grouting holes on the surface of the tentacle, shot toward the soil around the pile head, and combined with the soil to form a solidified body with high strength.

[0018] Compared with the prior art, the significant improvements of the present invention are: 1) the design of matching the outer sleeve with the inner drill rod is adopted, and the movement of the inner drill rod in the outer sleeve is controlled by screwing in the thread, which is easy to operate; 2) the raised protrusions on the surface of the outer sleeve can increase the surface friction coefficient and increase the friction resistance on the pile side; the penetration of the inner drill rod effectively increases the anchoring length of the spiral pile and improves the bearing performance; 3) through secondary grouting, and using extended tentacles to penetrate deep into the soil for grouting, the wrapping effect of the cement slurry is enhanced; the tentacles can be extended to allow them to penetrate deeply into the soil, thereby strengthening the contact with the soil and enhancing the grouting effect.

[0019] In order to more clearly illustrate the functional characteristics and structural parameters of the present invention, further description is given below in conjunction with the accompanying drawings and specific implementation methods. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of this application. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0021] Figure 1 It is an overall cross-sectional view of the present invention;

[0022] Figure 2 This is a schematic diagram of an inner drill rod with multiple holes at the end of the present invention;

[0023] Figure 3 This is a schematic diagram of a fully perforated outer sleeve of the present invention;

[0024] Figure 4 This is a schematic diagram of the tentacle of the present invention;

[0025] Figure 5 This is a schematic diagram of the connection between the tentacle and the pile head of the present invention;

[0026] Figure 6 It is a schematic diagram of the construction process of the present invention;

[0027] The reference numerals in the figure are: 1-pile body, 2-grouting protrusion, 3-spiral blade, 4-grouting port, 5-first internal grouting channel, 6-rod body, 7-pile head, 8-tentacle, 9-micro grouting hole, 10-thread, 11-second internal grouting channel. DETAILED DESCRIPTION

[0028] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments; based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0029] like Figure 1-Figure 5 As shown, a full-section grouting spiral pile with a porous end enlarged head comprises a full-section perforated outer sleeve and a porous end inner drill rod; the full-section perforated outer sleeve comprises a pile body 1, and the pile body 1 is provided with an internal thread; the porous end inner drill rod comprises a rod body 6 and a pile head 7, the pile head 7 is an inverted cone, connected to the lower end of the rod body 6, the outer side of the rod body 6 is provided with an external thread 10, and the full-section perforated outer sleeve and the porous end inner drill rod are connected by threads; the full-section perforated outer sleeve and the porous end inner drill rod are provided with grouting channels, and the outer surfaces of the pile body 1 and the pile head 7 are provided with a plurality of grouting outlets connected to the grouting channels.

[0030] Specifically, in one embodiment, a plurality of grouting nozzles 2 are provided on the outer surface of the pile body 1, a first internal grouting channel 5 is provided in the pipe wall of the pile body 1, a grouting port 4 is provided at the upper end of the first internal grouting channel 5, and the lower end of the first internal grouting channel 5 is connected to the plurality of grouting nozzles 2.

[0031] Specifically, in one embodiment, a plurality of spiral blades 3 are welded to the outer surfaces of the pile body 1 and the pile head 7 .

[0032] Specifically, in one embodiment, the pile head 7 is provided with a plurality of tentacles 8 for spraying slurry, a second internal grouting channel 11 is provided inside the shaft 6, a grouting port 4 is provided at the upper end of the second internal grouting channel 11, and the lower end of the second internal grouting channel 11 is connected to the plurality of tentacles 8.

[0033] Specifically, in one embodiment, there is a circular hole on the surface of the pile head 7, and the tentacle is installed in the circular hole on the surface of the pile head 7 by snapping; the tentacle 8 is two small tubes nested in each other, which can be freely extended and retracted to lengthen or shorten the tentacles; a plurality of small holes are provided on the surface of the tentacle 8 as micro grouting holes 9.

[0034] Specifically, in one embodiment, the rod shaft 6 is longer than the pile shaft 1 , and the upper portion of the rod shaft 6 extends out of the pile shaft 1 .

[0035] Specifically, in one embodiment, the second internal grouting channel 11 gradually narrows from top to bottom.

[0036] Specifically, in one embodiment, the grouting port 4 provided at the upper end of the first internal grouting channel 5 or the second internal grouting channel 11 is connected to an external grouting device.

[0037] like Figure 6 As shown, a method for forming a spiral pile with a multi-hole end enlarged head and full-section grouting comprises the following steps:

[0038] S1. The outer casing with full opening holes is tightly connected with the multi-hole inner drill rod at the end through threads. During construction, the spiral pile is vertically lifted with the pile head facing downward, and then slowly drilled into the soil along the direction of the spiral blade until the entire length of the outer casing with full opening holes enters the soil;

[0039] S2, the first grouting, the grouting equipment is connected to the grouting port at the upper end of the outer casing with full-section openings, and the high water-cement ratio cement slurry prepared in advance is injected into the grouting port under high pressure, and the cement slurry is ejected outward through the grouting protrusion along the first internal grouting channel, penetrates into the surrounding soil, and combines with the soil;

[0040] S3. The piling equipment is connected to the inner drill rod and the second piling begins. The porous inner drill rod at the end goes down along the thread and goes deeper into the soil along the spiral blade at the pile head.

[0041] S4. After the end porous inner drill rod reaches the maximum depth, the second grouting is carried out. The grouting equipment is connected to the upper grouting port of the end porous inner drill rod, and the high water-cement ratio cement slurry prepared in advance is injected into the grouting port under high pressure; when entering the second internal grouting channel in the inner drill rod, it becomes narrower and narrower as it goes downwards. Due to the narrow tube effect, the flow rate of the cement slurry gradually increases, and when it flows to the tentacles at the pile head, it has achieved a relatively high flow rate, which can flush the tentacles out of the pile head and penetrate into the surrounding soil; at the same time, the high-flow cement slurry is ejected outward from the micro-grouting holes on the surface of the tentacle, shot toward the soil around the pile head, and combined with the soil to form a solidified body with high strength.

[0042] Specifically, in one embodiment, the site is leveled before piling.

[0043] Specifically, in one embodiment, during piling, the pile body is slowly screwed into the soil in the direction of the spiral blades.

[0044] Specifically, in one embodiment, during the second grouting, the grouting equipment is set with a pressure that can push the pile head tentacles out of the pile.

[0045] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0046] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A full-section grouting screw pile with a porous end-type enlarged head, characterized in that: The invention comprises a fully perforated outer casing and an end multi-hole inner drill rod; the fully perforated outer casing comprises a pile body (1), and the pile body (1) is provided with an internal thread; the end multi-hole inner drill rod comprises a rod body (6) and a pile head (7), the pile head (7) is an inverted cone, connected to the lower end of the rod body (6), the outer side of the rod body (6) is provided with an external thread (10), and the fully perforated outer casing and the end multi-hole inner drill rod are connected by threads; the fully perforated outer casing and the end multi-hole inner drill rod are provided with grouting channels, and the outer surfaces of the pile body (1) and the pile head (7) are provided with a plurality of grouting outlets connected to the grouting channels.

2. The full-section grouting screw pile with a porous end enlarged head according to claim 1 is characterized in that: The outer surface of the pile body (1) is provided with a plurality of grouting protrusions (2), a first internal grouting channel (5) is provided in the pipe wall of the pile body (1), a grouting port (4) is provided at the upper end of the first internal grouting channel (5), and the lower end of the first internal grouting channel (5) is connected to the plurality of grouting protrusions (2).

3. The full-section grouting screw pile with a porous end-enlarged head according to claim 1 is characterized in that: A plurality of spiral blades (3) are welded to the outer surfaces of the pile body (1) and the pile head (7).

4. The full-section grouting screw pile with a porous end-enlarged head according to claim 1 is characterized in that: The pile head (7) is provided with a plurality of tentacles (8) for spraying slurry, the shaft (6) is provided with a second internal grouting channel (11), the upper end of the second internal grouting channel (11) is provided with a grouting port (4), and the lower end of the second internal grouting channel (11) is connected to the plurality of tentacles (8).

5. The full-section grouting screw pile with a porous end-enlarged head according to claim 4 is characterized in that: There is a circular hole on the surface of the pile head (7), and the tentacle is installed in the circular hole on the surface of the pile head (7) through a buckle; the tentacle (8) is two small tubes nested in each other, which can be freely extended and retracted so that the tentacles are extended or shortened; and a plurality of small holes are arranged on the surface of the tentacle (8) as micro grouting holes (9).

6. The full-section grouting screw pile with a porous end-enlarged head according to claim 1 is characterized in that: The rod shaft (6) is longer than the pile shaft (1), and the upper part of the rod shaft (6) extends out of the pile shaft (1).

7. The full-section grouting screw pile with a porous end-enlarged head according to claim 1 is characterized in that: The second internal grouting channel (11) gradually narrows from top to bottom.

8. The full-section grouting screw pile with a porous end-enlarged head according to claim 2 or 4, characterized in that: The grouting port (4) provided at the upper end of the first internal grouting channel (5) or the second internal grouting channel (11) is connected to an external grouting device.

9. A method for forming a spiral pile with a multi-hole end enlarged head and full-section grouting, the method being based on a spiral pile with a multi-hole end enlarged head and full-section grouting according to any one of claims 1 to 8, characterized in that: The following steps are involved: S1. The outer casing with full opening holes is tightly connected with the multi-hole inner drill rod at the end through threads. During construction, the spiral pile is vertically lifted with the pile head facing downward, and then slowly drilled into the soil along the direction of the spiral blade until the entire length of the outer casing with full opening holes enters the soil; S2, the first grouting, the grouting equipment is connected to the grouting port at the upper end of the outer casing with full-section openings, and the high water-cement ratio cement slurry prepared in advance is injected into the grouting port under high pressure, and the cement slurry is ejected outward through the grouting protrusion along the first internal grouting channel, penetrates into the surrounding soil, and combines with the soil; S3. The piling equipment is connected to the inner drill rod and the second piling begins. The porous inner drill rod at the end goes down along the thread and goes deeper into the soil along the spiral blade at the pile head. S4. After the end porous inner drill rod reaches the maximum depth, the second grouting is carried out. The grouting equipment is connected to the upper grouting port of the end porous inner drill rod, and the high water-cement ratio cement slurry prepared in advance is injected into the grouting port under high pressure; when entering the second internal grouting channel in the inner drill rod, it becomes narrower and narrower as it goes downwards. Due to the narrow tube effect, the flow rate of the cement slurry gradually increases, and when it flows to the tentacles at the pile head, it has achieved a relatively high flow rate, which can flush the tentacles out of the pile head and penetrate into the surrounding soil; at the same time, the high-flow cement slurry is ejected outward from the micro-grouting holes on the surface of the tentacle, shot toward the soil around the pile head, and combined with the soil to form a solidified body with high strength.

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