Large-diameter combined pile used in limited space and construction method thereof

Abstract

The invention belongs to the technical field of precast piles, and discloses a large-diameter combined pile used in a confined space and a construction method thereof, and the large-diameter combined pile used in the confined space comprises a pile cylinder unit, a connecting assembly and a miniature pile group. Each pile cylinder unit comprises a pile cylinder part and a connecting part, the pile cylinder parts extend in the first direction, filling cavities penetrating through the pile cylinder parts in the first direction are formed in the pile cylinder parts, the connecting parts extend in the first direction and are arranged in the pile cylinder parts in a penetrating mode, and the multiple pile cylinder units are sequentially connected in the first direction to form an open caisson body. The multiple pile barrel pieces are parallel to one another in the first direction and are coaxially arranged, and in every two adjacent pile barrel pieces, one connecting piece is connected to the other connecting piece through a connecting assembly. Through the arrangement, the large-diameter combined pile used in the limited space can be constructed in the limited space, the construction quality and the operation efficiency are improved, and the environmental protection property is higher.

Description

Technical Field

[0001] The invention relates to the technical field of pile foundation construction, and in particular to a large-diameter combined pile used in a confined space and a construction method thereof. Background Art

[0002] With the continuous acceleration of urbanization, construction projects are gradually developing underground and in narrow spaces. In projects such as the renovation of old buildings in the central area of ​​the city, the construction of subway tunnels, the construction of underground integrated pipe corridors, and the construction under high-voltage power lines, there are often restrictions such as small construction sites and complex surrounding environments, which puts higher requirements on pile foundation construction technology. At present, the pile foundation construction processes that can be used in confined spaces mainly include anchor static piles, micro piles, and cast-in-place piles. Anchor static piles use the building's own weight load as the pile pressure reaction force to press the pile body into the soil. They are suitable for operations under low clearance of existing buildings, but the pile length and pile diameter are limited by the size of the reaction load, and the bearing capacity of a single pile is usually not high. Micro piles are usually constructed with small geological drilling rigs, and the pile diameter and single pile bearing capacity are limited. Although bored cast-in-place piles can construct piles with larger pile diameters and pile lengths, conventional construction equipment cannot be used in confined spaces, and mud pollution will be caused when the mud wall protection process is used for construction. Therefore, the construction of large-diameter, high-bearing-capacity pile foundations in confined spaces has always been a common problem faced by the industry. Summary of the invention

[0003] The purpose of the present invention is to provide a large-diameter composite pile for use in a confined space, which can be constructed in the confined space, improves the construction quality and operation efficiency, and is more environmentally friendly.

[0004] To achieve this object, the present invention adopts the following technical solutions:

[0005] A large-diameter composite pile for use in confined spaces, comprising:

[0006] A pile barrel unit, comprising a pile barrel member and a connecting member, wherein the pile barrel member is extended along a first direction and has a filling cavity therein which is penetrated along the first direction, and the connecting member is extended along the first direction and penetrated in the pile barrel member;

[0007] A connecting assembly, wherein the pile barrel units are provided in plurality, and the plurality of pile barrel units are sequentially connected along the first direction to form a caisson body, in the caisson body, the plurality of pile barrel members are arranged parallel to each other and coaxially along the first direction, and one of the connecting members of two adjacent pile barrel members is connected to the other connecting member through the connecting assembly;

[0008] A micro pile group is connected to the caisson body.

[0009] Optionally, the pile barrel member is provided with a plurality of connection holes, the connection holes are arranged through along the first direction, the plurality of connection holes are arranged at intervals along the circumference of the pile barrel member, a plurality of connection members are provided, and the plurality of connection members are respectively inserted into the plurality of connection holes.

[0010] Optionally, the pile tube member is provided with an in-well grouting hole, the connecting hole is connected to the outside through the in-well grouting hole, and the connecting component is provided with a grouting hole, and both ends of the grouting hole are respectively connected to the connecting hole and the outside.

[0011] Optionally, the connection assembly includes a fixing member and a fastener, the fixing member is arranged at one end of the pile barrel member, one end of the connecting member is passed through the fixing member and fixedly connected to the fastener, so that the fixing member can be abutted against the pile barrel member.

[0012] Optionally, a limiting groove is provided on the pile tube member, and the fixing member abuts against a groove wall of the limiting groove.

[0013] Optionally, the connection assembly further includes a locking member, and one of the connection members of two adjacent pile barrel members is connected to the other connection member via the locking member, and two ends of the locking member are respectively sleeved on the two connection members.

[0014] Optionally, a plurality of skeleton nets are provided in the pile barrel member, the skeleton nets are extended along the circumference of the pile barrel member, and the plurality of skeleton nets are arranged at intervals along the radial direction of the pile barrel member.

[0015] Optionally, the pile barrel component further includes an out-of-hole grouting hole, and two ends of the out-of-hole grouting hole are respectively provided with a grouting inlet end and a grouting outlet end, the grouting inlet end is arranged at one end of the pile barrel component, and the grouting outlet end is arranged on the outer peripheral wall of the pile barrel component.

[0016] Optionally, the large-diameter composite pile for use in a confined space further includes a slurry plug, and the slurry plug is arranged at the slurry outlet end.

[0017] Another object of the present invention is to provide a construction method for large-diameter composite piles in confined spaces, which can be constructed in confined spaces, improves construction quality and operating efficiency, and ensures that the quality and performance of the composite piles meet design requirements.

[0018] To achieve this object, the present invention adopts the following technical solutions:

[0019] A construction method for large-diameter composite piles in confined spaces, used for the large-diameter composite piles in confined spaces as described above, the construction method for large-diameter composite piles in confined spaces comprising:

[0020] Step 1: Install and fix the crimping equipment;

[0021] Step 2: Install the first pile barrel unit;

[0022] Step 3: connect the connecting piece of the next pile barrel unit with the connecting piece of the previous pile barrel unit along the first direction through the connecting assembly, and insert the pile barrel member of the next pile barrel unit into the connected connecting piece, so as to fit the end faces of the two pile barrel members and connect them to each other;

[0023] Step 4: Apply prestress to the connecting parts;

[0024] Step 5: injecting grout between the pile tube and the connecting piece;

[0025] Step 6: Press the pile tube unit downward into the ground and dig out the soil inside the filling cavity;

[0026] Step 7: When the pile barrel unit reaches the predetermined position, stop pressing down, and repeat steps 3 to 6 until the pile barrel unit reaches the designed depth;

[0027] Step 8: Drill multiple holes at the bottom of the caisson body to a preset depth, then lower steel bars to the bottom of the holes, and pour concrete to form a micro pile group;

[0028] Step 9: pouring bottom sealing concrete into the filling cavity and pumping out the groundwater infiltrated into the filling cavity;

[0029] Step 10: grouting outside the well in sections;

[0030] Step 11: Add filling material into the filling cavity and pour capping concrete.

[0031] Beneficial effects of the present invention:

[0032] The present invention provides a large-diameter composite pile for use in a confined space, which includes a pile barrel unit, a connecting assembly and a micro pile group. The pile barrel unit includes a pile barrel member and a connecting member. The pile barrel member is extended along a first direction, and a filling cavity is provided inside the pile barrel member and is provided through the first direction. The filling cavity is used to fill concrete and other fillers to improve the strength and bearing capacity of the overall structure of the composite pile. The connecting member extends along the first direction and is inserted into the pile barrel member so that the connecting members of multiple pile barrel members can be connected to each other. There are multiple pile barrel units, and the multiple pile barrel units are connected in sequence along the first direction to form a caisson body. Since the pile barrel units can be prefabricated in a factory and then transported to the site for splicing and assembly, the construction process is simplified and the operation efficiency is improved. Moreover, the above-mentioned assembly method has low requirements for the construction space and can be constructed under limited space. In the caisson body, multiple pile barrel members are arranged parallel to each other and coaxially along the first direction to ensure that the caisson body is subjected to balanced force and avoid eccentricity that affects the normal force of the composite pile. Among two adjacent pile barrel parts, one connecting part is connected to the other connecting part through a connecting assembly, and multiple pile barrel parts can be tightly connected together through the connecting assembly, thereby improving the horizontal load resistance and earthquake resistance of the composite pile. Since the pile barrel unit is small in size, it is convenient to transport, and does not require large-scale construction equipment, and the construction occupies a small area, which is particularly suitable for large-diameter pile foundations in confined spaces. Since the construction does not require the use of mud and chemical slurry, it will not affect the surrounding environment and is more environmentally friendly. The construction process is a repetitive modular operation, which is simple and convenient, with low process noise and easy construction management. The micro-pile group is connected to the caisson body, which improves the pile foundation bearing capacity of the composite pile. Through the above-mentioned settings, the large-diameter composite piles used in confined spaces in this application can be constructed in confined spaces, which improves the construction quality and operating efficiency, and is more environmentally friendly.

[0033] The present invention also provides a construction method for large-diameter composite piles in confined spaces. First, a crimping device is installed and fixed to facilitate the downward pressing operation of the pile barrel unit. Then, the first section of the pile barrel unit is installed to provide a solid foundation for the installation of subsequent pile barrel units, thereby ensuring the initial stability and accuracy of the overall structure. Then, the connecting piece of the next section of the pile barrel unit is connected to the connecting piece of the previous section of the pile barrel unit in a first direction through a connecting assembly to ensure the connection strength and stability between the connecting pieces. The pile barrel piece of the next section of the pile barrel unit is inserted into the already connected connecting piece, which is more convenient and simple to operate and improves the construction efficiency. The end faces of the two pile barrel pieces are fitted and connected to each other, thereby achieving a tight connection between the pile barrel units, ensuring the continuity and integrity of the caisson body when subjected to force, and improving the stability and bearing capacity of the structure. Prestress is applied to the connecting piece, and then grouting is injected into the gap between the pile barrel piece and the connecting piece, which not only improves the bonding force between the pile barrel piece and the connecting piece, but also can prevent the connecting piece from corroding. After that, the pile barrel unit is pressed down into the stratum, and the soil inside the filling cavity is dug out to provide space for the filling cavity, so as to carry out subsequent concrete pouring or other filling operations, and also help the pile barrel unit to better combine with the stratum. When the pile barrel unit reaches the predetermined position, the downward pressure is stopped, and steps three to six are repeated until the pile barrel unit reaches the designed depth, thereby ensuring the depth and stability of the overall structure. Then, multiple boreholes are drilled at the bottom of the caisson body to a preset depth, steel bars are lowered to the bottom of the boreholes, and concrete is poured to form a micro pile group, thereby improving the pile foundation bearing capacity of the composite pile. Then, the bottom sealing concrete is poured into the filling cavity, and the groundwater infiltrated in the filling cavity is extracted, so that the operator can perform segmented out-of-well grouting in the filling cavity, so that the slurry outside the well is fully and evenly mixed with the stratum soil, thereby enhancing the bonding force between the stratum and the pile barrel unit, and improving the pull-out resistance and overall stability of the composite pile. Finally, filler is placed in the filling cavity, and the capping concrete is poured to complete the closure of the filling cavity, further improving the bearing capacity and stability of the composite pile. Through the above arrangement, the construction method of large-diameter composite piles in confined spaces of the present application can be constructed in confined spaces, thereby improving construction quality and operating efficiency, and ensuring that the quality and performance of the composite piles meet design requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 It is a schematic diagram of the construction of large-diameter composite piles in a confined space provided by an embodiment of the present invention;

[0035] Figure 2 is a cross-sectional view of a pile barrel member provided by an embodiment of the present invention;

[0036] Figure 3 is a partial structural schematic diagram of a pile barrel member provided by an embodiment of the present invention;

[0037] Figure 4is a schematic diagram of connecting two adjacent pile barrel units provided by an embodiment of the present invention;

[0038] Figure 5 is a schematic diagram of a slurry plug provided in an embodiment of the present invention being disposed in a pile barrel;

[0039] Figure 6 is a schematic diagram of a first plug body provided by an embodiment of the present invention;

[0040] Figure 7 is a schematic diagram of a second plug body provided by an embodiment of the present invention;

[0041] Figure 8 is a schematic diagram of a third plug body provided by an embodiment of the present invention;

[0042] Fig. 9 It is a flow chart of a construction method for large-diameter composite piles in a confined space provided by an embodiment of the present invention;

[0043] Fig.10 is a first schematic diagram of a crimping device provided by an embodiment of the present invention;

[0044] Fig.11 It is a second schematic diagram of the crimping device provided in an embodiment of the present invention.

[0045] In the figure:

[0046] 100, crimping equipment; 10, press table; 101, base; 102, support arm; 103, oil cylinder; 104, piston; 105, hoop; 106, slide rail; 20, press ring; 201, hanging ear;

[0047] 1. Pile barrel unit; 11. Pile barrel member; 111. Filling cavity; 112. Connecting hole; 113. Grouting hole in the well; 114. Limiting groove; 115. Skeleton net; 116. Grouting hole outside the well; 1161. First section hole; 1162. Second section hole; 12. Connecting piece; 2. Connecting assembly; 21. Slurry discharge hole; 22. Fixing piece; 23. Fastener; 24. Locking piece; 3. Slurry plug; 31. First plug body; 32. Second plug body; 33. Third plug body; 4. Micro pile group. DETAILED DESCRIPTION

[0048] The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the present invention, rather than to limit the present invention. It should also be noted that, for ease of description, only parts related to the present invention, rather than all structures, are shown in the accompanying drawings.

[0049] In the description of the present invention, unless otherwise clearly specified and limited, the terms "connected", "connected", and "fixed" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0050] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0051] In the description of this embodiment, the terms "upper", "lower", "right" and other directions or positional relationships are based on the directions or positional relationships shown in the drawings, and are only for the convenience of description and simplified operation, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are only used to distinguish in the description and have no special meaning.

[0052] like Figure 1-Figure 8 As shown, this embodiment provides a large-diameter composite pile for use in a confined space (hereinafter referred to as a "combined pile"), which includes a pile barrel unit 1 and a connecting assembly 2. The pile barrel unit 1 includes a pile barrel member 11 and a connecting member 12. The pile barrel member 11 is extended along a first direction, and a filling cavity 111 is provided inside the pile barrel member 11, which is provided along the first direction. The connecting member 12 extends along the first direction and is penetrated in the pile barrel member 11. There are multiple pile barrel units 1, and the multiple pile barrel units 1 are sequentially connected along the first direction to form a caisson body. In the caisson body, multiple pile barrel members 11 are parallel to each other and coaxially arranged along the first direction. Among two adjacent pile barrel members 11, one connecting member 12 is connected to the other connecting member 12 through the connecting assembly 2, and the micro pile group 4 is connected to the caisson body.

[0053] In this embodiment, the pile barrel unit 1 includes a pile barrel member 11 and a connecting member 12. The pile barrel member 11 is extended along the first direction and is provided with a filling cavity 111 extending along the first direction. The filling cavity 111 is used to fill concrete and other fillers to improve the strength and bearing capacity of the overall structure of the composite pile. The connecting member 12 extends along the first direction and is inserted into the pile barrel member 11 so that the connecting members 12 of multiple pile barrel members 11 can be connected to each other. There are multiple pile barrel units 1, and multiple pile barrel units 1 are connected in sequence along the first direction to form a caisson body. Since the pile barrel unit 1 can be prefabricated in the factory and then transported to the site for assembly, the construction process is simplified and the work efficiency is improved. Moreover, the above-mentioned assembly method has low requirements for the construction space and can be constructed under limited space. In the caisson body, multiple pile barrel members 11 are arranged parallel to each other and coaxially along the first direction to ensure that the caisson body is subjected to balanced force and avoid eccentricity that affects the normal force of the composite pile. Among two adjacent pile barrel parts 11, one connecting part 12 is connected to the other connecting part 12 through the connecting assembly 2, and the connecting assembly 2 can be used to tightly connect multiple pile barrel parts 11 together, thereby improving the horizontal load resistance and earthquake resistance of the composite pile. Since the pile barrel unit 1 is small in size, it is convenient to transport, and does not require large-scale construction equipment, and the construction occupies a small area, it is particularly suitable for large-diameter pile foundations in confined spaces. Since the construction does not require the use of mud and chemical slurry, it will not affect the surrounding environment, and it is more environmentally friendly. In addition, the construction process is a repeated modular operation, which is simple and convenient, with low process noise and easy construction management. The micro-pile group 4 is connected to the caisson body, which improves the pile foundation bearing capacity of the composite pile. Through the above-mentioned settings, the large-diameter composite piles used in confined spaces in this embodiment can be constructed in confined spaces, which improves the construction quality and operating efficiency, and is more environmentally friendly.

[0054] It should be noted that in this embodiment, the first direction is the vertical direction, so as to facilitate the hoisting and splicing of the pile tube unit 1 and the pressing of the combined pile into the stratum. In other embodiments, the first direction can be adjusted according to the actual construction of the combined pile, and is not limited here.

[0055] In addition, part of the pile head of the micro pile group 4 is placed in the filling cavity 111, and by pouring concrete into the bottom of the filling cavity 111, the caisson body located at the upper part and the micro pile group 4 located at the lower part are connected into an integral structure to improve the connection strength between the two, which is beneficial to improving the pile foundation bearing capacity of the combined pile. Among them, the micro pile group 4 can be a small diameter cast-in-place pile or a prefabricated pile. When the micro pile group 4 adopts a cast-in-place pile, its longitudinal steel bar should extend into the filling cavity 111 to a certain length, and when the micro pile group 4 adopts a prefabricated pile, its pile top should be higher than the bottom of the caisson body to a certain height.

[0056] The specific structure of large-diameter composite piles used in confined spaces is described below:

[0057] Specifically, a hoisting hole is provided on the pile barrel member 11 to facilitate on-site hoisting operations. The hoisting hole is provided through the pile barrel member 11 in a radial direction to facilitate the insertion of hoisting ropes.

[0058] Specifically, Figure 1-Figure 3 As shown, the pile barrel member 11 is provided with a plurality of connection holes 112, thereby increasing the connection points between the pile barrel members 11, making the connection between adjacent pile barrel members 11 more stable. The connection holes 112 are arranged through along the first direction, and the plurality of connection holes 112 are arranged at intervals along the circumference of the pile barrel member 11, ensuring that the pile barrel member 11 can be evenly distributed when subjected to stress, thereby avoiding stress concentration. There are a plurality of connection members 12, and the plurality of connection members 12 are respectively inserted into the plurality of connection holes 112. When two adjacent pile barrel members 11 are connected toward each other, the plurality of connection holes 112 on the two pile barrel members 11 are aligned one by one, so as to ensure that the plurality of connection members 12 on one of the pile barrel members 11 can be inserted into the plurality of connection holes 112 on the other pile barrel member 11 in a one-to-one correspondence, thereby improving the convenience of operation. It can be understood that, for the caisson body, multiple connecting parts 12 are connected in sequence to form a connecting body, and are inserted into the corresponding connecting holes 112 in multiple pile tube parts 11. The two ends of the connecting body can be connected to the two ends of the caisson body through a connecting component 2 or welding to ensure the stability of the overall structure. The specific connection method of the two ends of the connecting body is not limited here.

[0059] Specifically, Figure 1-Figure 4 As shown, the pile barrel member 11 is provided with an in-well grouting hole 113, and the connecting hole 112 is connected to the outside through the in-well grouting hole 113, so that the operator can inject the sealing material into the connecting hole 112 through the in-well grouting hole 113, which is equivalent to injecting the sealing material into the gap between the pile barrel member 11 and the connecting member 12, so as to improve the bonding force between the pile barrel member 11 and the connecting member 12, and at the same time protect the connecting member 12 and prevent the connecting member 12 from corrosion. The connection component 2 is provided with a grouting hole 21, and the two ends of the grouting hole 21 are respectively connected to the connecting hole 112 and the outside. By providing the grouting hole 21, the excess slurry or gas generated during the grouting process can be discharged to ensure the grouting effect.

[0060] More specifically, if Figure 4As shown, the well grouting hole 113 is arranged to extend radially along the pile barrel member 11, so that the sealing material can be directly injected into the connecting hole 112, thereby achieving the reinforcement of the connection portion between the pile barrel member 11 and the connecting member 12. The end of the well grouting hole 113 connected to the outside is used to inject sealing materials such as epoxy resin and cement mortar into the connecting hole 112. These materials have good adhesion and curing strength, and can effectively fill the gap in the connecting hole 112, thereby improving the connection strength between the pile barrel member 11 and the connecting member 12. Moreover, the grouting hole 21 is arranged to be inclined upward, so that the slurry can be discharged upward more easily under the action of its own gravity and grouting pressure, thereby avoiding the accumulation of slurry in the connecting hole 112. When two adjacent pile barrel units 1 are connected in sequence along the vertical direction, grouting is performed through the grouting hole 113 in the well of the pile barrel unit 1 at the bottom, and the grouting hole 21 at the upper end of the pile barrel unit 1 is monitored to see if there is grout discharged, so as to ensure that the connection hole 112 is fully grouted, thereby improving the connection strength between the pile barrel member 11 and the connection member 12. In addition, a monitoring unit can be provided at the grouting hole 21 to realize automatic detection and improve operation efficiency. The monitoring unit is a conventional device in the art, so there is no need to elaborate on its working principle.

[0061] Specifically, Figure 1-Figure 4 As shown, the connection assembly 2 includes a fixing member 22 and a fastener 23. The fixing member 22 is arranged at one end of the pile member 11 to play a role in positioning and supporting. One end of the connection member 12 is passed through the fixing member 22 and fixedly connected to the fastener 23, so that the fixing member 22 can be abutted against the pile member 11, so that the connection member 12 can be stably connected to the pile member 11 and is not easy to loosen or fall off. Figure 2 and Figure 4 As shown, for a pile barrel unit 1, a plurality of fixing members 22 are provided, and the plurality of fixing members 22 are arranged one by one with the plurality of connecting members 12, and the plurality of connecting members 12 are correspondingly inserted into a plurality of evenly distributed connecting holes 112 to ensure the connection stability and uniform force between the connecting members 12 and the pile barrel member 11. Among them, the fixing members 22 can be made of steel plates or steel sections, which can withstand the force and torque transmitted by the connecting members 12 to meet the requirements of sufficient strength and rigidity; and the fasteners 23 can be made of nuts or rivets to achieve the fastening effect of the connecting members 12 and the pile barrel member 11; and the connecting members 12 can be made of steel bars or composite fibers to facilitate the assembly and performance requirements of the pile barrel unit 1, and the specific structures of the fixing members 22, fasteners 23 and connecting members 12 are not further limited here.

[0062] More specifically, if Figure 4As shown, the pile tube member 11 is provided with a limit groove 114, and the fixing member 22 abuts against the groove wall of the limit groove 114, thereby ensuring that the fixing member 22 can accurately align with the limit groove 114 and be installed in place during the installation process. Moreover, the above arrangement makes it difficult for the connecting member 12 to be displaced when subjected to external loads, thereby improving the stability of the connection. In addition, the grouting hole 21 is arranged on the fixing member 22 at an angle upward to ensure the grouting monitoring effect.

[0063] More specifically, Figure 1-Figure 4 As shown, the connection assembly 2 also includes a locking member 24. Among two adjacent pile barrel members 11, one of the connecting members 12 is connected to the other connecting member 12 through the locking member 24, so that the connection between the two adjacent pile barrel members 11 is more secure. The two ends of the locking member 24 are respectively sleeved on the two connecting members 12, which can effectively prevent the connecting members 12 from relative displacement when subjected to external loads. The locking member 24 can be a nut or a locking bolt, and the specific structure of the locking member 24 is not limited here, as long as it can achieve the above-mentioned functions.

[0064] Specifically, Figure 4 As shown, one end of the connection hole 112 is provided with an enlarged end, and the diameter of the enlarged end is 1.2 to 1.3 times the diameter of the connection member 12, so that the locking member 24 can be accommodated in the enlarged end. The diameter of the connection hole 112 is 1.1 to 1.2 times the diameter of the connection member 12, so that the connection member 12 can be inserted into the connection hole 112. At the same time, the locking member 24 will be clamped on the enlarged end, which can ensure that the connection member 12 is prevented from being pulled out of the connection hole 112 when the connection member 12 is prestressed.

[0065] Specifically, Figure 1-Figure 3 As shown, a plurality of skeleton nets 115 are provided in the pile barrel member 11, and the skeleton nets 115 are arranged along the circumference of the pile barrel member 11, which can form a stable support system, effectively resist the influence of external loads on the pile barrel member 11, and prevent the structure from being damaged. The plurality of skeleton nets 115 are arranged at intervals along the radial direction of the pile barrel member 11 to ensure that the strength and rigidity of the pile barrel member 11 in all directions can be evenly improved.

[0066] More specifically, if Figure 2As shown, in this embodiment, the skeleton net 115 includes longitudinal bars and stirrups. A plurality of longitudinal bars are provided and arranged along the extension direction of the pile barrel 11. A plurality of longitudinal bars are arranged at intervals along the circumference of the pile barrel 11, and stirrups are arranged on the outer periphery of the plurality of longitudinal bars. A plurality of stirrups are provided and the plurality of stirrups are arranged at intervals along the extension direction of the pile barrel 11 to improve the overall structural strength of the skeleton net 115. In other embodiments, the skeleton net 115 includes a steel mesh, and the steel mesh is arranged in the pile barrel 11 to improve the self strength of the pile barrel 11. It can be understood that the specific structure of the skeleton net 115 is not limited here, as long as the above-mentioned functions can be achieved.

[0067] Specifically, Figure 1-Figure 5 As shown, the pile barrel member 11 also includes an external grouting hole 116, which is used to improve the connection quality between each pile barrel unit 1 and the pile side friction resistance. The two ends of the external grouting hole 116 are respectively provided with a grouting inlet end and a grouting outlet end. The grouting inlet end is arranged at one end of the pile barrel member 11 along the first direction, and the grouting outlet end is arranged on the outer peripheral wall of the pile barrel member 11. The grouting material is injected from the grouting inlet end, and the grouting liquid is uniformly injected into the soil around the pile barrel member 11 through the grouting pressure. After the grouting liquid solidifies in the soil, it can fill the pores and cracks in the soil, enhance the density and strength of the soil, and help improve the overall stability and bearing capacity of the pile barrel member 11 and the surrounding soil.

[0068] More specifically, if Figure 1-Figure 5 As shown, in this embodiment, the out-hole grouting hole 116 includes a first section hole 1161 and a second section hole 1162. The first section hole 1161 and the connecting hole 112 are parallel to each other and arranged at intervals. The grouting end is arranged on the first section hole 1161, and the second section hole 1162 extends along the radial direction of the pile barrel 11. The two ends are respectively connected to the first section hole 1161 and the outside, so that the operator can inject slurry through the slurry inlet end and discharge the slurry to the space between the pile barrel 11 and the surrounding soil through the slurry outlet end, thereby forming a more uniform reinforcement layer, which can improve the lateral friction resistance of the combined pile foundation on the one hand, and further improve the integrity and seismic resistance of the pile foundation on the other hand. It should be noted that in the actual operation process, part of the connecting hole 112 can be used as the first section hole 1161 for out-hole grouting operation, and the second section hole 1162 can be opened to connect the first section hole 1161, which can simplify the construction process and improve the operation efficiency.

[0069] More specifically, the diameter of the second section hole 1162 is 1.2 to 1.3 times the diameter of the first section hole 1161. By increasing the diameter of the second section hole 1162, the resistance loss along the slurry can be reduced, so that the slurry can diffuse along a larger diameter range after injection, thereby more effectively penetrating into the soil around the pile tube 11, forming a wider reinforcement layer, and improving the overall bearing capacity and stability of the soil.

[0070] Specifically, Figure 1-Figure 5 As shown, the large-diameter composite pile used in a confined space also includes a slurry plug 3, which is arranged at the slurry outlet end. When the grouting operation outside the well is completed, in order to prevent the soil on the periphery of the pile barrel 11 from entering the pile barrel 11 through the grouting hole 116 outside the well, the slurry plug 3 is inserted and connected to the grouting hole 116 outside the well, so as to protect the internal environment of the filling cavity 111 and prevent foreign matter from entering.

[0071] More specifically, Figure 1-Figure 8 As shown, in other embodiments, since the two ends of the second hole 1162 are respectively connected to the filling cavity 111 and the outside, in order to facilitate the segmented off-hole grouting operation, the slurry plug 3 can be inserted into the second hole 1162, including a first plug body 31, a second plug body 32 and a third plug body 33. The first plug body 31 is provided with a through hole for connecting to the first hole 1161. The length of the second plug body 32 is shorter than that of the first plug body 31, and the length of the third plug body 33 is equal to that of the first plug body 31, so as to block the first through hole. During the segmented outhole grouting process, the first section holes 1161 of the plurality of pile barrel components 11 are connected in sequence along the vertical direction. At this time, the plurality of first plug bodies 31 are correspondingly inserted into the second section holes 1162 of the plurality of pile barrel components 11. The operator is located in the filling chamber 111. First, the upper first plug body 31 of the pile barrel component 11 at the bottom is replaced with the second plug body 32. Then, grouting is injected into the first section hole 1161 through the slurry inlet end on the top pile barrel component 11. After the slurry flows through the plurality of first section holes 1161 and the through holes of the plurality of first plug bodies 31, it is grouted out of the well through the second section hole 1162 on the bottom pile barrel component 11. After the outhole grouting of the pile barrel component 11 at the bottom is completed, the second plug body 32 is replaced by the third plug body 33 to achieve plugging. Then, the first plug body 31 on the next section of the pile barrel component 11 is replaced from bottom to top with the second plug body 32. The above steps are repeated until the segmented outhole grouting operation of all pile barrel components 11 is completed. Through the above-mentioned segmented grouting operation, the slurry is mixed more evenly and the bonding force between the caisson body and the surrounding soil is stronger.

[0072] like Figure 1-Figure 11 As shown, this embodiment also provides a construction method for large-diameter composite piles in confined spaces, which can be constructed in confined spaces, improves construction quality and operation efficiency, and ensures that the quality and performance of the composite piles meet the design requirements. The method specifically includes the following steps:

[0073] Step 1: Install and fix the crimping device 100.

[0074] In the above step 1, regarding the specific structure and working principle of the crimping device 100:

[0075] like Fig.10 and Fig.11As shown, the crimping device 100 includes a plurality of press tables 10 and a press ring 20, and the plurality of press tables 10 are arranged at intervals along the circumference of the press ring 20. The press table 10 includes a base 101, a support arm 102, a cylinder 103, a piston 104, a hoop 105 and a slide rail 106. The support arm 102 is fixedly connected to the base 101, and the cylinder 103 is slidably connected to the support arm 102 in a vertical direction through the hoop 105. One end of the piston 104 is fixedly connected to the base 101, and the other end is slidably connected to the cylinder 103. Under hydraulic drive, the piston 104 contracts and extends relative to the cylinder 103, so that the cylinder 103 can slide up and down relative to the support arm 102. The hoop 105 is fixedly connected to the oil cylinder 103, and two pins are symmetrically arranged on the hoop 105. The pressure ring 20 is provided with a plurality of hanging ears 201 at intervals along its outer peripheral wall. The pins can be inserted into the hanging ears 201, thereby locking the oil cylinder 103, the hoop 105 and the pressure ring 20 with each other, so that the compressive load of the oil cylinder 103 can be transmitted to the pressure ring 20. Since the pressure ring 20 is coaxially arranged with the pile barrel member 11, the downward movement of the oil cylinder 103 drives the pressure ring 20 to move downward, thereby providing a uniform downward pressure load to the pile barrel member 11.

[0076] Step 2: Install the first pile tube unit 1.

[0077] In the above step 2, a fixing seat is first installed on the ground, and the fixing seat is fixed to the ground by pressing H-shaped steel into the ground, driving ground anchors or piling weights, so as to provide a reaction force for the subsequent pressing of the pile barrel 11 into the ground. A guide rail is provided on the fixing seat to prevent the pile barrel 11 from tilting. The fixing seat is a mechanical structure well known in the art and will not be described in detail here.

[0078] In addition, if Figure 1 As shown, a boot-shaped portion is provided at one end of the first pile barrel unit 1 facing the ground, and the diameter of the boot-shaped portion gradually decreases from top to bottom to reduce the soil resistance during the pressing process of the pile barrel unit 1, thereby improving construction efficiency, reducing energy consumption, and helping to maintain the stability of the pile barrel unit 1 during the pressing process, preventing tilting or deviation, and ensuring construction quality and safety.

[0079] Step 3: Connect the connecting piece 12 of the next pile barrel unit 1 with the connecting piece 12 of the previous pile barrel unit 1 along the first direction through the connecting assembly 2, and pass the pile barrel component 11 of the next pile barrel unit 1 through the connected connecting piece 12, so as to fit the end faces of the two pile barrel components 11 and connect them to each other.

[0080] In the above step three, for the last section of the pile barrel unit 1, the fixing member 22 is arranged at one end of the pile barrel member 11, one end of the connecting member 12 is passed through the fixing member 22 and fixedly connected to the fastener 23, so that the fixing member 22 can be abutted against the pile barrel member 11, so that the connecting member 12 can be stably connected to the last section of the pile barrel member 11, and the connecting member 12 of the last section of the pile barrel unit 1 is connected to the connecting member 12 of the next section of the pile barrel unit 1 through the locking member 24, and then the adhesive is applied on the end face of the last section of the pile barrel member 11, and the pile barrel member 11 of the next section of the pile barrel unit 1 is passed through the connected connecting member 12, so that the end faces of the two pile barrel members 11 are bonded to each other. Among them, the adhesive can be an epoxy-type water-based adhesive or a polyurethane-type water-curing adhesive to ensure the connection strength between the pile barrel members 11.

[0081] Step 4: Apply prestress to the connecting member 12.

[0082] In the above step four, when the designed prestress value is small, the fastener 23 can be tightened by a torque wrench so that the fixing part 22 is tightly abutted against the pile barrel member 11, so that the connecting member 12 reaches the corresponding prestress value; and when the designed prestress value is large, the connecting member 12 can be pre-tensioned to the corresponding predetermined force value by a through-hole jack, and then the two ends of the connecting member 12 can be locked on the pile barrel member 11, thereby improving the crack resistance, rigidity and stability of the overall structure, while also saving material costs.

[0083] Step 5: inject grout between the pile tube member 11 and the connecting member 12.

[0084] In the above step five, for two adjacent pile barrel units 1, sealing materials such as epoxy resin and cement mortar are injected into the connection hole 112 through the grouting hole 113 in the well on the pile barrel component 11 at the bottom end, so as to improve the bonding force between the pile barrel component 11 and the connection component 12, and prevent the connection component 12 from corrosion. A grouting hole 21 is provided on the connection component 2, and the grouting hole 21 is inclined upward, and the two ends are respectively connected to the connection hole 112 and the outside. The slurry is more easily discharged upward under the action of its own gravity and grouting pressure. By monitoring whether there is slurry discharged from the grouting hole 21 of the pile barrel component 11 at the upper end, it is ensured that the connection hole 112 is fully grouted, and the connection strength between the pile barrel component 11 and the connection component 12 is improved.

[0085] Step 6: Press the pile tube unit 1 downward into the ground, and dig out the soil inside the filling cavity 111.

[0086] In the upper step six, the connected pile barrel unit 1 is pressed down by the crimping device 100, and the soil inside the caisson is dug out by the excavation equipment. Specifically, when the ballasting process is performed, the pressing ring 20 is first placed on the pile barrel member 11, and a slide rail 106 is arranged on the base 101. The support arm 102 is slidably connected to the slide rail 106, so that the support arm 102 can move inward toward the pressing ring 20 along the radial direction of the pressing ring 20, so that the pin on the hoop 105 is inserted into the hanging ear 201 on the pressing ring 20, and then the hydraulic drive cylinder 103 moves downward, thereby driving the pile barrel member 11 to be pressed into the formation. When the pressing process is completed, the support arm 102 moves outward in the direction away from the pressing ring 20, so that the pin is separated from the hanging ear 201, and the pressing ring 20 is taken out, so as to enter the pressing process of the next section of the pile barrel member 11. Moreover, by synchronously pressing the pile tube 11 through multiple oil cylinders 103, not only the disturbance to the surrounding soil during the pile foundation construction is reduced, the impact on surrounding buildings is reduced, but also the construction accuracy is improved, and the problem of easy tilting of the pile body during traditional construction is solved.

[0087] Step 7: When the pile tube unit 1 reaches the predetermined position, stop pressing down, and repeat steps 3 to 6 until the pile tube unit 1 reaches the designed depth. The predetermined position can be determined according to the actual construction work, and no further limitation is made here.

[0088] Step 8: Drill multiple holes at the bottom of the caisson body to a preset depth, then lower steel bars to the bottom of the holes, and pour concrete to form a micro pile group 4.

[0089] In the above step eight, a small drilling rig is used to drill a plurality of small-diameter holes at the bottom of the caisson body to a preset depth, and then steel bars are lowered to the bottom of the holes, and then the concrete casting operation of the micro pile group 4 is carried out. Part of the pile head of the micro pile group 4 is placed in the filling cavity 111, and by pouring concrete into the bottom of the filling cavity 111, the caisson body located at the upper part and the micro pile group 4 located at the lower part are connected to form an integral structure to improve the connection strength between the two, which is conducive to improving the pile foundation bearing capacity of the combined pile. Among them, the micro pile group 4 can be a small-diameter cast-in-place pile or a precast pile. When the micro pile group 4 adopts a cast-in-place pile, its longitudinal steel bar should extend into the filling cavity 111 to a certain length, and when the micro pile group 4 adopts a precast pile, its pile top should be higher than the bottom of the caisson body to a certain height.

[0090] Step 9: pour the bottom seal concrete into the filling cavity 111, and extract the groundwater that has infiltrated the filling cavity 111, so that the operators can enter the filling cavity 111 to perform segmented outhole operations. It should be noted that the inner diameter of the filling cavity 111 of the first pile barrel unit 1 should be larger than the inner diameter of the filling cavity 111 of other pile barrel units 1 to prevent shear slippage of the bottom seal concrete.

[0091] Step 10: Grouting outside the well in sections.

[0092] In the above step 10, the grouting material is injected from the grouting end, and the grouting pressure is used to uniformly inject the slurry into the soil around the pile tube member 11. After the slurry solidifies in the soil, it can fill the pores and cracks in the soil, enhance the density and strength of the soil, and help improve the overall stability and bearing capacity of the pile tube member 11 and the surrounding soil. It should be noted that the specific step of segmented out-of-hole grouting can refer to the first plug body 31, the second plug body 32 and the third plug body 33 to achieve the method of segmented grouting, which will not be repeated here.

[0093] Step 11, put the filling material into the filling cavity 111, and pour the capping concrete. The filling material includes dry hard concrete, cement sand mixture, cement, crushed stone, pebbles and slag, which will not be explained in detail here. It should be noted that the radial thickness of the second pile barrel member 11 from top to bottom is greater than the radial thickness of other pile barrel members 11, that is, the inner diameter of the filling cavity 111 of the second pile barrel member 11 is smaller than the inner diameter of the filling cavity 111 of other pile barrel members 11, so as to prevent the capping concrete from shearing and slipping with the inner wall of the pile barrel member 11 under a large load.

[0094] It should be noted that if Figure 9-11 As shown, when the designed pile length is longer, the upper half of the composite pile can adopt the construction method for large-diameter composite piles in confined spaces, and the lower half of the composite pile adopts cast-in-place concrete. Such a configuration can reduce the load requirements for the crimping equipment 100 and reduce the weight of the crimping equipment 100. Moreover, the upper loose strata are surrounded by the composite piles, avoiding the risk of hole collapse, eliminating the need for mud wall protection, reducing environmental pollution, and improving environmental protection. In the case of water construction, no additional operations such as throttling and construction of cofferdams are required, thereby reducing construction costs. The specific construction process is as follows:

[0095] It should be noted that the pile barrel unit 1 is first pressed into the soft soil layer, and as the depth of the pile barrel unit 1 increases, the main body of the caisson is continuously extended. Due to the limited reaction load in the confined space, when the bottom of the pile barrel member 11 is pressed into the dense and hard soil layer, the resistance increases sharply, and the pile barrel unit 1 is stopped from being pressed, and a small geological drilling rig or pile barrel pressing equipment is used to construct a micro pile group 4 at the bottom of the caisson body. By pouring concrete at the bottom of the filling cavity 111, the caisson body located at the upper part and the micro pile group 4 located at the lower part are connected to form an integral structure. Then, fillers are thrown into the filling cavity 111 and vibrated to make it dense, so that the various parts of the combined pile are synergistically stressed. The caisson body bears a large side friction resistance, and the micro pile group 4 located at the lower part is located on the bearing layer, which can increase the pile end resistance of the combined pile. Through the above-mentioned arrangement, the large-diameter composite piles for confined spaces and the construction method thereof of this embodiment can solve the construction difficulties of large-diameter piles in confined spaces, do not require large-scale construction equipment, improve the bearing capacity of a single pile, ensure the construction quality and operating efficiency, and at the same time be beneficial to environmental protection, avoiding the problem of mud wall protection required for the construction of cast-in-place piles in loose strata.

[0096] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. For those skilled in the art, various obvious changes, readjustments and substitutions can be made without departing from the protection scope of the present invention. It is not necessary and impossible to list all the embodiments here. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. Used for large diameter composite piles in confined spaces, characterized by: include: A pile barrel unit (1) comprises a pile barrel component (11) and a connecting component (12); the pile barrel component (11) is extended along a first direction and is provided with a filling cavity (111) extending along the first direction; the connecting component (12) is extended along the first direction and is inserted into the pile barrel component (11); A connecting assembly (2), wherein the pile barrel units (1) are provided with a plurality of them, and the plurality of pile barrel units (1) are sequentially connected along the first direction to form a caisson body, in the caisson body, the plurality of pile barrel components (11) are arranged parallel to each other and coaxially along the first direction, and in two adjacent pile barrel components (11), one of the connecting components (12) is connected to the other connecting component (12) through the connecting assembly (2); A micro pile group (4) is connected to the caisson body.

2. The large-diameter composite pile for use in confined spaces according to claim 1, characterized in that: The pile barrel member (11) is provided with a plurality of connection holes (112), the connection holes (112) are arranged through along the first direction, the plurality of connection holes (112) are arranged at intervals along the circumference of the pile barrel member (11), a plurality of connection members (12) are provided, and the plurality of connection members (12) are respectively inserted into the plurality of connection holes (112).

3. The large-diameter composite pile for use in confined spaces according to claim 2, characterized in that: The pile tube member (11) is provided with an in-well grouting hole (113), the connection hole (112) is connected to the outside through the in-well grouting hole (113), and the connection component (2) is provided with a grouting hole (21), and the two ends of the grouting hole (21) are respectively connected to the connection hole (112) and the outside.

4. The large-diameter composite pile for use in confined spaces according to claim 1, characterized in that: The connecting assembly (2) comprises a fixing member (22) and a fastening member (23); the fixing member (22) is arranged at one end of the pile tube member (11); one end of the connecting member (12) is passed through the fixing member (22) and is fixedly connected to the fastening member (23), so that the fixing member (22) can be abutted against the pile tube member (11).

5. The large-diameter composite pile for use in confined spaces according to claim 4, characterized in that: The pile tube member (11) is provided with a limiting groove (114), and the fixing member (22) abuts against a groove wall of the limiting groove (114).

6. The large-diameter composite pile for use in confined spaces according to claim 1, characterized in that: The connection assembly (2) further comprises a locking member (24), wherein one of the connection members (12) of two adjacent pile tube members (11) is connected to the other connection member (12) via the locking member (24), and the two ends of the locking member (24) are respectively sleeved on the two connection members (12).

7. The large-diameter composite pile for use in confined spaces according to claim 1, characterized in that: A plurality of skeleton nets (115) are arranged in the pile barrel component (11), the skeleton nets (115) are extended along the circumference of the pile barrel component (11), and the plurality of skeleton nets (115) are arranged at intervals along the radial direction of the pile barrel component (11).

8. The large-diameter composite pile for use in confined spaces according to claim 1, characterized in that: The pile barrel component (11) further comprises an out-of-hole grouting hole (116), and two ends of the out-of-hole grouting hole (116) are respectively provided with a grouting inlet end and a grouting outlet end, the grouting inlet end is arranged at one end of the pile barrel component (11), and the grouting outlet end is arranged on the outer peripheral wall of the pile barrel component (11).

9. The large-diameter composite pile for use in confined spaces according to claim 8, characterized in that: The large-diameter composite pile for use in a confined space further comprises a slurry plug (3), wherein the slurry plug (3) is arranged at the slurry outlet end.

10. A construction method for large diameter composite piles in confined spaces, characterized in that: The large-diameter composite pile for use in a confined space as claimed in any one of claims 1 to 9, wherein the construction method of the large-diameter composite pile for use in a confined space comprises: Step 1: Install and fix the crimping equipment; Step 2: installing the first pile barrel unit (1); Step 3: Connect the connecting piece (12) of the next pile barrel unit (1) with the connecting piece (12) of the previous pile barrel unit (1) along the first direction through the connecting assembly (2), and insert the pile barrel component (11) of the next pile barrel unit (1) onto the connected connecting piece (12), so that the end surfaces of the two pile barrel components (11) are fitted and connected to each other; Step 4: applying prestress to the connecting member (12); Step 5: injecting grout between the pile tube member (11) and the connecting member (12); Step 6: Press the pile tube unit (1) downward into the ground, and dig out the soil inside the filling cavity (111); Step 7: When the pile tube unit (1) reaches the predetermined position, stop pressing down, and repeat steps 3 to 6 until the pile tube unit (1) reaches the designed depth; Step 8: Drill multiple holes at the bottom of the caisson body to a preset depth, then lower steel bars to the bottom of the holes, and pour concrete to form a micro pile group (4); Step nine, pouring bottom sealing concrete into the filling cavity (111), and extracting the groundwater that has infiltrated the filling cavity (111); Step 10: grouting outside the well in sections; Step 11: Add filling material into the filling cavity (111) and pour capping concrete.

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