Steel concrete column pile and its construction method

Abstract

The present application proposes a steel concrete column pile, which includes a prefabricated pipe pile, an H steel pile and an expansion part, the expansion part is located at the pile top of the prefabricated pipe pile, and the H steel pile is installed on the expansion part; when the steel concrete column pile extends in the vertical direction, in the horizontal direction, the outer peripheral surface of the expansion part outwardly exceeds the outer peripheral surface of the prefabricated pipe pile; the expansion part includes a steel cylinder, which is fixedly connected to the prefabricated pipe pile, one end of the core steel cage extends into the center hole of the prefabricated pipe pile, and the other end extends into the steel cylinder, and a concrete core extending into the center hole of the prefabricated pipe pile is poured in the steel cylinder; after the bottom plate of the underground structure reaches the maintenance period, at least part of the H steel pile that exceeds the bottom plate upward is removed. The present application also proposes a construction method for the steel concrete column pile. The present application can better solve the problems of poor stability of the supporting columns inside the foundation pit in the soft soil layer and poor water stopping effect.

Description

Technical Field

[0001] The invention relates to a steel concrete column pile and a construction method of the steel concrete column pile. Background Art

[0002] At present, the commonly used supporting columns for foundation pit support are mainly "cast-in-place piles + steel lattice columns". This structure has a high bearing capacity, but the construction speed is slow and the cost is high. In the construction of some foundation pits, H-shaped steel is used as the supporting column. The construction speed is fast and it can be directly driven into the underground soil layer. Since this type of supporting column is actually a friction pile, when the soil layer under the foundation pit is relatively weak, the stability of the supporting column in the soil is poor, and a longer supporting column is required to meet the needs, which not only increases the difficulty of construction, but also increases the construction cost. In addition, in order to improve the anti-twisting performance of the supporting column, steel pipes are used as supporting columns during the construction of some foundation pits. The construction speed and economy of steel pipes are relatively good, but groundwater can easily penetrate into the underground structure through the inner cavity of the steel pipe, reducing the waterproof performance of the bottom plate of the underground structure, and it is also easy to destroy the integrity of the bottom plate.

[0003] In addition, since the support columns are set inside the foundation pit, they will be fixed by the bottom plate during the construction process. When removing the support columns, only the support columns above the bottom plate can be removed, and some of the support columns are retained underground. These support columns cannot meet the support requirements of the underground structure, and additional pull-out piles are required. Due to the existence of the support columns, it will be more difficult to construct the pull-out piles. Sometimes, the existence of the support columns will also destroy the overall layout of the pull-out piles, increasing the difficulty of designing the pull-out piles. In addition, since some of the support columns retained underground have a smaller cross-section, during the use of the underground structure, over time, under the action of underground buoyancy, some of the support columns retained underground will cause stress concentration on the bottom plate, causing cracks in the bottom plate and affecting the waterproof performance of the bottom plate. Summary of the invention

[0004] In order to solve the problem of poor stability of the supporting columns inside the foundation pit in the soft soil layer and poor water-stopping effect, the present application first proposes a steel concrete column pile, which includes a prefabricated pipe pile, an H-steel pile and an expansion part, the expansion part is located at the pile top of the prefabricated pipe pile, and the H-steel pile is installed on the expansion part; the end of the H-steel pile facing the prefabricated pipe pile is called the steel pile connection end, and the end of the prefabricated pipe pile facing the H-steel pile is called the pipe pile connection end; when the steel concrete column pile extends in the vertical direction, in the horizontal direction, the outer peripheral surface of the expansion part outwardly exceeds the outer peripheral surface of the prefabricated pipe pile;

[0005] The expansion part includes a steel cylinder, which is fixedly connected to the pipe pile connection end of the prefabricated pipe pile, one end of the core-casting steel cage extends into the central hole of the prefabricated pipe pile, and the other end of the core-casting steel cage extends into the steel cylinder, a concrete core is poured in the steel cylinder, and the concrete core extends into the central hole of the prefabricated pipe pile;

[0006] The steel pile connection end of the H steel pile is located in the concrete core, and a water stop plate is welded on the H steel pile, and there is a distance between the water stop plate and the expansion part; when the steel concrete column pile is located underground, the H steel pile is located on the upper side of the prefabricated pipe pile, and the water stop plate is located in the bottom plate of the underground structure; after the bottom plate of the underground structure reaches the maintenance period, at least part of the H steel pile that exceeds the bottom plate upward is removed. The prefabricated pipe pile can be a prestressed concrete square pile (PRC pile for short), a prestressed concrete pipe pile (PC pile for short) or a prestressed concrete centrifugal pipe pile (PHC pile for short), preferably a prestressed concrete centrifugal pipe pile (PHC pile for short).

[0007] In the steel concrete column piles of the present application, pile bodies formed by two different structures, namely prefabricated pipe piles and H-steel piles, are arranged, and an enlarged portion is arranged between the prefabricated pipe piles and the H-steel piles. When in use, the prefabricated pipe piles and the enlarged portion are located below the bottom surface of the foundation pit, and the H-steel piles serve as supporting columns in the foundation pit for supporting horizontal supports. After completing the task of serving as supporting columns, the H-steel piles are removed; the prefabricated pipe piles and the enlarged portion are retained underground as pull-out piles or compression piles.

[0008] By utilizing the larger contact area between the prefabricated pipe piles and the soil, sufficient friction can be provided for the steel concrete column piles, while the high strength of the prefabricated pipe piles can be utilized to provide support for the building, and the excellent anti-corrosion performance of the prefabricated pipe piles can be utilized to ensure the service life of the steel concrete column piles. The setting of the expansion part not only serves to connect the prefabricated pipe piles and the H-steel piles together, but also serves to improve the pull-out resistance of the steel concrete column piles. Since the steel concrete column piles in this application can be used as pull-out piles, the steel concrete column piles can be considered together when designing the pull-out piles, so as to avoid the layout of the pull-out piles being destroyed due to the interference of the supporting columns in the prior art.

[0009] Since the enlarged portion in the present application has a larger cross-section, it can have a larger contact area with the bottom plate of the underground structure, and can provide a more uniform support force for the bottom plate, thereby preventing the bottom plate from being subjected to excessive local force and affecting the stability of the bottom plate. The concrete core can effectively prevent groundwater from entering the underground structure upward along the center hole of the prefabricated pipe pile. The H-steel pile ensures the rapid installation of the supporting parts of each horizontal support in the foundation pit. For example, the supporting parts such as steel corbels can be quickly welded or connected to the H-steel piles, and after the horizontal support is removed, the H-steel piles can be quickly cut off and recycled, thereby improving the construction progress of the underground structure and reducing some construction costs.

[0010] The steel concrete column pile in the present application is composed of two pile bodies with different structures and performances, which can give full play to the characteristics of each pile body, so that the steel concrete column pile has the functions of supporting column and anti-pullout pile.

[0011] After the base plate of the underground structure reaches the maintenance period, at least part of the H-steel piles of the steel concrete column piles that extend upwards beyond the base plate will be removed to avoid affecting the construction and use of other facilities of the underground structure. Since the main purpose of the H-steel piles is to support horizontal supports, they must be removed after they have completed supporting the horizontal supports.

[0012] Furthermore, when the steel concrete column pile extends in the vertical direction, the outer peripheral surface of the enlarged portion extends outwardly beyond the outer peripheral surface of the prefabricated pipe pile in the horizontal direction, and the outer peripheral surface of the enlarged portion extends outwardly beyond the outer peripheral surface of the H steel pile in the horizontal direction. This design enables a step to be formed between the enlarged portion and the H steel pile and the prefabricated pipe pile, and the step is used to stably maintain the steel concrete column pile in the soil.

[0013] In order to enable the steel concrete column pile to withstand greater external forces in the vertical direction, the central axis of the prefabricated pipe pile coincides with the central axis of the H steel pile. After the central axes of the prefabricated pipe pile and the H steel pile coincide, the steel concrete column pile can maintain sufficient stability when subjected to external forces, and will not tilt due to the horizontal distance between the central axes of the prefabricated pipe pile and the H steel pile, thus maintaining the safety of the foundation pit during the construction process.

[0014] In order to ensure the connection strength between the H-steel pile and the prefabricated pipe pile, the cast-in-place steel cage is welded to the H-steel pile.

[0015] Specifically, the steel cylinder is welded to the connecting end plate of the prefabricated pipe pile. In order to facilitate the connection of two prefabricated pipe piles, connecting end plates are pre-buried at both ends of the prefabricated pipe pile. The connecting end plates can not only conveniently fix the steel cylinder to the prefabricated pipe pile, but also ensure the connection strength.

[0016] To ensure the connection strength between the enlarged portion and the prefabricated pipe pile, the length of the concrete core in the center hole of the prefabricated pipe pile is ≥2 meters and ≥5D, where D is the inner diameter of the center hole of the prefabricated pipe pile.

[0017] In order to improve the strength of the expansion part, an expansion part steel cage is set in the steel cylinder, and the expansion part steel cage is cast in the concrete core. After the expansion part steel cage is set, not only the strength of the expansion part can be improved, but also the bending strength of the steel concrete column pile can be improved. When there is only a cast-in-core steel cage, the cast-in-core steel cage and the steel cylinder are mainly connected by concrete. Concrete has a high compressive strength, but its tensile strength is low. After adding the expansion part steel cage, the tensile strength of the expansion part can be improved, and the overall strength of the steel concrete column pile can be guaranteed accordingly.

[0018] Secondly, the present application also provides a construction method for any of the above-mentioned steel concrete column piles, and the construction method specifically comprises the following steps:

[0019] (1) sinking the prefabricated pipe pile at the setting position so that the upper end of the prefabricated pipe pile remains above the ground, and suspending the sinking of the prefabricated pipe pile;

[0020] (2) Install the steel cylinder to the upper end of the prefabricated pipe pile, insert the lower end of the cast-core steel cage into the center hole of the prefabricated pipe pile, and make the upper end of the cast-core steel cage located in the steel cylinder; insert the H steel pile into the steel cylinder, and weld the cast-core steel cage to the H steel pile;

[0021] Pour concrete into the steel cylinder and allow the concrete to enter the center hole of the prefabricated pipe pile to form a steel concrete column pile;

[0022] (3) using a steel casing to sink the steel concrete column pile to a first set elevation, and then removing the steel casing;

[0023] (4) Excavate the foundation pit. When the installation elevation of the horizontal support is reached, suspend the excavation of the foundation pit and install the column brackets and horizontal supports;

[0024] (5) Continue to excavate the foundation pit and complete it, weld the water stop plate on the H steel pile, and construct the bottom plate of the underground structure so that the water stop plate is located inside the bottom plate;

[0025] (6) Remove the portion of the H-steel pile above the base plate.

[0026] In this construction method, the steel concrete column piles are completed during the construction process, and the method of sinking and making is adopted. If the steel concrete column piles are completed and then sunk, it will not only cause transportation difficulties, but also affect the sinking progress, and may also cause damage to the steel concrete column piles.

[0027] The steel concrete column piles in this application are formed by connecting prefabricated pipe piles and H-steel piles together. Although an expansion part is set between the two, which can play a certain role in strengthening the connection strength between the two, since the overall length of the steel concrete column piles is relatively large, and the expansion part at least exceeds the prefabricated pipe piles in the radial direction, additional reinforcement measures are required during transportation. Even if the steel concrete column piles are made at the construction site, when lifting the steel concrete column piles, not only larger lifting equipment is required, but also since the connection between the prefabricated pipe piles and the H-steel piles is still a weak point, during the lifting process, the steel concrete column piles may be broken at the connection between the prefabricated pipe piles and the H-steel piles. When constructing steel concrete column piles by sinking and making, there is no need to use large-scale lifting equipment. Only lifting equipment that can complete ordinary prefabricated pipe piles and H-steel piles is used, and the damage to the expansion part that may be caused during lifting is avoided.

[0028] In order to increase the construction speed, the concrete in the steel cylinder is fast-setting and early-strength concrete, and the grade of the fast-setting and early-strength concrete is preferably ≥ C40.

[0029] In order to prevent the expansion part from affecting the construction of the underground structure, the upper end surface of the expansion part is lower than the second set elevation of the bottom surface of the foundation pit. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a schematic diagram of steel concrete column piles located underground.

[0031] Figure 2 yes Figure 1 The enlarged view of part A in the figure has the base plate of the underground structure removed for clarity.

[0032] Figure 3 yes Figure 2 Top view of the .

[0033] Figure 4 This is a schematic diagram after the pipe pile is partially sunk into the ground.

[0034] Figure 5 This is a schematic diagram after the steel concrete column pile production is completed.

[0035] Figure 6 This is a schematic diagram after the steel concrete column piles have been sunk.

[0036] Figure 7 This is a schematic diagram after the horizontal support installation is completed.

[0037] Figure 8 This is a schematic diagram after the foundation pit excavation is completed.

[0038] Fig. 9 This is a schematic diagram after the construction of the base plate of the underground structure is completed.

[0039] Fig.10 This is a schematic diagram after the portion of the H-steel pile located above the base plate has been removed. DETAILED DESCRIPTION

[0040] See also Figure 1 , Figure 2 and Figure 3 A steel concrete column pile comprises a prefabricated pipe pile 11, an H steel pile 26 and an enlarged portion 30, wherein the enlarged portion 30 is mounted on the pile top of the prefabricated pipe pile 11, and the H steel pile 26 is mounted on the enlarged portion 30. The end of the H steel pile 26 facing the prefabricated pipe pile 11 is called a steel pile connection end 265, and the end of the prefabricated pipe pile 11 facing the H steel pile 26 is called a pipe pile connection end 111. When the steel concrete column pile extends in the vertical direction, the outer peripheral surface of the enlarged portion extends outwardly beyond the outer peripheral surface of the prefabricated pipe pile in the horizontal direction. Figure 1A schematic diagram showing the steel concrete column piles being located in a foundation pit 70.

[0041] The expansion portion 30 includes a steel cylinder 31, which specifically includes a cylindrical steel sleeve 311 and an annular ring plate 312 connected to one end of the steel sleeve 311, the inner hole of the ring plate is sleeved on the connecting end plate 13 on the pipe pile connecting end 111 of the prefabricated pipe pile 11, and the connecting end plate 13 is an annular steel plate prefabricated on the end surface of the prefabricated pipe pile 11. The steel sleeve 311 extends in a direction away from the prefabricated pipe pile 11.

[0042] One end of the cast-core steel cage 21 extends into the center hole 12 of the precast pipe pile 11, and the other end of the cast-core steel cage 21 extends into the steel sleeve 311 of the steel cylinder 31. A support plate 22 is welded to one end of the cast-core steel cage 21 located in the center hole 12 of the precast pipe pile 11. A concrete core 23 is poured in the steel cylinder 31, and the concrete core extends into the center hole 12 of the precast pipe pile and fills the area of ​​the center hole 12 above the support plate 22.

[0043] The steel pile connection end 265 of the H steel pile 26 is located in the concrete core, and the steel bars of the core-cast steel cage 21 are welded to the flange 261 and the web 263 of the H steel pile 26. A water stop plate 262 is welded to the H steel pile 26, and there is a distance between the water stop plate 262 and the enlarged portion 30.

[0044] When the steel concrete column pile is located underground, the H steel pile 26 is located on the upper side of the prefabricated pipe pile 11, and the water stop plate 262 is located in the bottom plate 61 of the underground structure 60. After the bottom plate 61 of the underground structure reaches the maintenance period and completes the task of supporting the horizontal support, the H steel pile that exceeds the bottom plate 61 upward is removed. It can be understood that in other embodiments, the H steel pile that partially exceeds the bottom plate upward can also be used for other purposes, for example, it can be partially retained in the boss on the bottom plate or other concrete structures for continued use. At this time, only the part of the H steel pile that exceeds the boss or other concrete structure needs to be removed.

[0045] In order to increase the strength of the enlarged portion 30, an enlarged portion steel cage 32 is provided in the steel cylinder 31, and the enlarged portion steel cage 32 is cast in the concrete core 23. In this embodiment, the prefabricated pipe pile specifically adopts a PHC600 pipe pile, the inner diameter of the center hole of the PHC600 pipe pile is 340 mm, and the length of the concrete core 23 in the center hole of the prefabricated pipe pile is 2.5 meters, which is greater than 5 times the inner diameter of the center hole.

[0046] The steel cylinder 31 , the enlarged portion reinforcement cage 32 , the portion of the concrete core 23 located inside the steel cylinder 31 , and the portion of the cast-in-place reinforcement cage 21 located inside the steel cylinder 31 together form an enlarged portion.

[0047] It can be understood that in other embodiments, when the enlarged portion reinforcement cage is not provided, the enlarged portion does not include the enlarged portion reinforcement cage.

[0048] In this embodiment, when the steel concrete column pile extends in the vertical direction, in the horizontal direction, the outer peripheral surface of the expansion portion extends outwardly beyond the outer peripheral surface of the prefabricated pipe pile in the horizontal direction, and the outer peripheral surface of the expansion portion extends outwardly beyond the outer peripheral surface of the H steel pile in the horizontal direction. It can be understood that in other embodiments, when the steel concrete column pile extends in the vertical direction, in the horizontal direction, the outer peripheral surface of the expansion portion may only extend outwardly beyond the outer peripheral surface of the prefabricated pipe pile.

[0049] The central axis of the prefabricated pipe pile 11 in this embodiment coincides with the central axis of the H-steel pile 26. Figure 2 In the figure, the axis 300 is both the center axis of the prefabricated pipe pile 11 and the center axis of the H-steel pile 26.

[0050] Example 2

[0051] This embodiment is to carry out specific construction on the steel concrete column piles in Example 1, and the construction method specifically includes the following steps:

[0052] (1) Please refer to Figure 4 Before constructing the steel concrete column piles, first complete the construction of the foundation pit retaining wall 51, and then construct the steel concrete column piles.

[0053] When constructing the steel concrete column pile, firstly sink the prefabricated pipe pile 11 at the setting position, so that the upper end of the prefabricated pipe pile is kept above the ground 100, and the sinking of the prefabricated pipe pile is suspended. The upper end of the prefabricated pipe pile is the pipe pile connection end 111.

[0054] (2) Please refer to Figure 5 , weld the ring plate 312 of the steel cylinder 31 to the connecting end plate 13 of the prefabricated pipe pile 11. Then place the enlarged steel cage 32 into the steel cylinder 31, and then insert the core steel cage 21 from top to bottom through the center hole of the enlarged steel cage 32 into the center hole of the prefabricated pipe pile, and make the upper end of the core steel cage be located in the steel cylinder 31. Then insert the H steel pile 26 into the steel cylinder 31, and weld the core steel cage 21 to the web and flange of the H steel pile 11.

[0055] Concrete is poured into the steel cylinder and allowed to enter the central hole of the prefabricated pipe pile to form a concrete core, so that the steel cylinder 31, the enlarged steel cage 32, the portion of the concrete core 23 located in the steel cylinder 31, and the portion of the core-cast steel cage 21 located in the steel cylinder 31 together form an enlarged portion 30. The upper end surface of the enlarged portion is lower than the second set elevation of the bottom surface of the foundation pit.

[0056] Complete the production of steel concrete column piles.

[0057] In this embodiment, the concrete is fast-setting early-strength concrete, and the concrete grade is C40. It can be understood that in other implementations, the concrete grade can also be higher.

[0058] (3) Please refer to Figure 6 , place the steel casing 200 against the enlarged portion 30 , and then use a pile driver to press the steel casing 200 downward to make the steel concrete column pile sink, and after reaching the first set elevation, remove the steel casing 200 .

[0059] (4) Please refer to Figure 7 , excavate the foundation pit 70, and when the installation elevation of the horizontal support 53 is reached, suspend the excavation of the foundation pit, install the column corbel 54 and the horizontal support 53 on the top of the H steel pile 26 of the steel concrete column pile, and connect the horizontal support 53 to the purlin 52 and support it on the column corbel 54.

[0060] (5) Please refer to Figure 8 , continue to excavate the foundation pit 70, so that the bottom surface 71 of the foundation pit reaches the second set elevation, and the excavation of the foundation pit is completed. Fig. 9 , a water stop plate 262 is welded on the H steel pile 26, a steel mesh is tied, and the steel mesh is welded together with the H steel pile 26. The bottom plate 61 of the underground structure 60 is constructed so that the water stop plate 262 is located inside the bottom plate 61.

[0061] In other embodiments, when tying the steel mesh, the steel bars of the steel mesh may also pass through the holes opened on the H-steel piles, or bypass the H-steel piles.

[0062] (6) Please refer to Fig.10 , continue to construct the underground structure upwards. After removing the horizontal supports supported on the H-steel piles, remove the part of the H-steel piles above the bottom plate. Fig.10 In the figure, reference numeral 264 indicates the remaining portion of the H-steel pile after the portion located above the bottom plate is removed.

Claims

1. Steel concrete column pile, characterized in that: It comprises a prefabricated pipe pile, an H-steel pile and an enlarged portion, wherein the enlarged portion is located at the top of the prefabricated pipe pile, and the H-steel pile is installed on the enlarged portion; the end of the H-steel pile facing the prefabricated pipe pile is called the steel pile connection end, and the end of the prefabricated pipe pile facing the H-steel pile is called the pipe pile connection end; when the steel concrete column pile extends in the vertical direction, in the horizontal direction, the outer peripheral surface of the enlarged portion outwardly exceeds the outer peripheral surface of the prefabricated pipe pile; the central axis of the prefabricated pipe pile coincides with the central axis of the H-steel pile; The expansion part includes a steel cylinder, which is fixedly connected to the pipe pile connection end of the prefabricated pipe pile, one end of the core-casting steel cage extends into the central hole of the prefabricated pipe pile, and the other end of the core-casting steel cage extends into the steel cylinder, a concrete core is poured in the steel cylinder, and the concrete core extends into the central hole of the prefabricated pipe pile; an expansion part steel cage is arranged in the steel cylinder, and the expansion part steel cage is poured in the concrete core; The steel pile connection end of the H steel pile is located in the concrete core, and a water stop plate is welded on the H steel pile, and there is a distance between the water stop plate and the expansion part; when the steel concrete column pile is located underground, the H steel pile is located on the upper side of the prefabricated pipe pile, and the water stop plate is located in the bottom plate of the underground structure; after the bottom plate of the underground structure reaches the maintenance period, at least part of the H steel piles that extend upward beyond the bottom plate are removed.

2. The reinforced concrete column pile according to claim 1, characterized in that: When the reinforced concrete column pile extends in the vertical direction, the outer peripheral surface of the enlarged portion extends outwardly beyond the outer peripheral surface of the prefabricated pipe pile in the horizontal direction, and the outer peripheral surface of the enlarged portion extends outwardly beyond the outer peripheral surface of the H-steel pile in the horizontal direction.

3. The reinforced concrete column pile according to claim 1, characterized in that: The cast-in-place steel cage is welded to the H-steel pile.

4. The reinforced concrete column pile according to claim 1, characterized in that: The steel cylinder is welded to the connecting end plate of the prefabricated pipe pile.

5. The reinforced concrete column pile according to claim 1, characterized in that: The length of the concrete core in the center hole of the prefabricated pipe pile is ≥2 meters and ≥5D, where D is the inner diameter of the center hole of the prefabricated pipe pile.

6. A method for constructing a steel concrete column pile, which is used to construct the steel concrete column pile according to any one of claims 1 to 5, characterized in that: The steps include: (1) Sink the prefabricated pipe pile at the installation location so that the upper end of the prefabricated pipe pile remains above the ground, and suspend the sinking of the prefabricated pipe pile; (2) Install the steel cylinder to the upper end of the prefabricated pipe pile, insert the lower end of the cast-in-core steel cage into the center hole of the prefabricated pipe pile, and make the upper end of the cast-in-core steel cage located in the steel cylinder; insert the H-steel pile into the steel cylinder, and weld the cast-in-core steel cage to the H-steel pile; Pour concrete into the steel cylinder and allow the concrete to enter the center hole of the prefabricated pipe pile to form a steel concrete column pile; (3) Use the steel casing to sink the steel concrete column pile to the first set elevation, and then remove the steel casing; (4) Excavate the foundation pit. When the installation elevation of the horizontal support is reached, suspend the excavation of the foundation pit and install the column brackets and horizontal supports; (5) Continue to excavate the foundation pit and complete it, weld the water stop plate on the H steel pile, and construct the bottom plate of the underground structure so that the water stop plate is located inside the bottom plate; (6) Remove the portion of the H-steel pile above the base plate.

7. The construction method according to claim 6, characterized in that: The concrete in the steel cylinder is fast-setting and early-strength concrete.

8. The construction method according to claim 6, characterized in that: The upper end surface of the enlarged portion is lower than the second set elevation of the bottom surface of the foundation pit.

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