A cross-shaped precast solid square pile splicing structure suitable for sandy soil liquefaction zones

Abstract

This utility model provides a cross-shaped precast solid square pile splicing structure suitable for sandy soil liquefaction zones, belonging to the field of building foundation engineering technology. It includes a precast reinforced concrete square pile body, comprising a first pile section and a second pile section that can be interlocked. The first pile section has a cross-shaped protrusion at its insertion end, and the second pile section has a cross-shaped groove at its insertion end that mates with the cross-shaped protrusion. Both the first and second pile sections have welded end plates at their insertion ends, and the reinforcing bars within the precast reinforced concrete square pile body are arranged along the entire length of the pile. This utility model, through the cross-shaped interlocking of the first and second pile sections and the arrangement of the reinforcing bars along the entire length of the pile body, and the fact that the insertion ends of the first and second pile sections can be welded through end plates, significantly improves the horizontal resistance of the precast pile splicing, enhances the shear resistance at the joint, and solves the problems of excessively long single piles and insufficient resistance to horizontal forces in precast square piles in deep sandy soil liquefaction strata.

Description

Technical Field

[0001] This utility model belongs to the field of building foundation engineering technology, and more specifically, it relates to a cross-shaped precast solid square pile splicing structure suitable for sand liquefaction zones. Background Technology

[0002] In construction engineering, precast piles are widely used due to their advantages such as high construction efficiency and controllable quality. Precast solid square piles are made of high-strength concrete, have a solid structure, can withstand greater pressure and bending and shear stress, have high bearing capacity and stability, and are suitable for various foundation conditions, especially for soft soil foundation reinforcement and foundation engineering of high-rise buildings.

[0003] However, soft soil foundations are widely composed of loose to slightly dense silt and fine sand, which are often classified as liquefiable soil in areas with seismic intensity VII and above. Because sandy soil liquefies under seismic loads, its strength decreases, severely impacting the stability of pile foundations.

[0004] Traditional precast solid square pile splicing structures present numerous problems when splicing piles in liquefiable sand layers. For example, they cannot effectively resist the horizontal forces generated during earthquakes, leading to pile tilting, weld fractures, and other damage. Furthermore, the excessive length of individual precast piles in deep liquefiable sand layers poses a significant challenge to construction. Therefore, developing a highly efficient and stable precast solid square pile splicing structure suitable for earthquake-prone liquefiable sand zones is of great importance. Utility Model Content

[0005] The purpose of this utility model is to provide a cross-shaped precast solid square pile splicing structure suitable for sandy soil liquefaction zones. This splicing structure adopts a cross-shaped insertion method, with reinforcing ribs set at the insertion point. The cross-shaped insertion splicing structure can resist horizontal forces, enhance the shear resistance of the joint, and overcome the problems of excessive length of traditional precast piles and their insufficient resistance to horizontal forces.

[0006] To achieve the above objectives, this utility model provides a cross-shaped precast solid square pile splicing structure suitable for sandy soil liquefaction zones, comprising a precast reinforced concrete square pile body, wherein the precast reinforced concrete square pile body includes a first pile section and a second pile section that can be interlocked; the first pile section has a cross-shaped protrusion at its insertion end, and the second pile section has a cross-shaped groove at its insertion end that mates with the cross-shaped protrusion; both the first pile section and the second pile section have welded end plates at their insertion ends, and the reinforcing bars inside the precast reinforced concrete square pile body are arranged along the entire length of the pile body.

[0007] Furthermore, reinforcing bars are pre-embedded in the splice ends of the first and second pile sections, and transverse bars are pre-embedded in the pile body of the precast reinforced concrete square pile near the splice ends of the first and second pile sections. The diameter of the reinforcing bars is the same as that of the main reinforcing bars in the pile body of the precast reinforced concrete square pile. The reinforcing bars are welded to the transverse bars, and the transverse bars and the end plates are welded to the main reinforcing bars.

[0008] Furthermore, the length of the transverse reinforcement from the splice end of the first or second pile section is 150-300 mm, and the diameter of the transverse reinforcement is the same as that of the main reinforcement.

[0009] Furthermore, the stirrups inside the precast reinforced concrete square pile are thickened and densified, with a diameter of 6 mm and a spacing of 50 mm.

[0010] Furthermore, the height of the cross-shaped protrusion and the depth of the cross-shaped groove are both 0.4L, where L is the side length of the precast reinforced concrete square pile.

[0011] Furthermore, the cross-sectional width of the cross-shaped protrusion is L / 3-1mm.

[0012] Furthermore, a cross-shaped channel steel is pre-embedded within the cross-shaped protrusion, and the channel steel is welded to the end plate.

[0013] Furthermore, the four protrusions at the insertion end of the second pile section are square protrusions, and each square protrusion is pre-embedded with square steel, which is welded to the end plate.

[0014] Furthermore, the thickness of both the channel steel and the square steel is 10-14 mm.

[0015] Furthermore, the end plate thickness is 20-24 mm.

[0016] Compared with the prior art, the present invention has the following technical effects: This utility model discloses a precast reinforced concrete square pile with a cross-shaped precast solid square pile splicing structure suitable for sandy soil liquefaction zones. The pile body includes a first pile section and a second pile section that can be spliced ​​in a cross shape. The auxiliary reinforcement bars inside the precast reinforced concrete square pile body are arranged along the entire length of the pile body. The splicing ends of the first pile section and the second pile section can be further welded through end plates. This significantly improves the horizontal resistance of the precast pile splicing and enhances the shear resistance at the joint. It solves the problems of excessively long single piles of precast square piles in deep sandy soil liquefaction strata and the inability to splice piles in sandy soil liquefaction layers. The welding construction efficiency is significantly improved, and it is suitable for pile foundation engineering in earthquake-prone sandy soil liquefaction strata.

[0017] Furthermore, the cross-shaped precast solid square pile splicing structure of this utility model, suitable for sandy soil liquefaction zones, also arranges reinforcing bars and transverse bars at the splice ends of the first and second pile sections. The transverse bars connect the reinforcing bars to the main bars, increasing the reinforcement ratio at the joint without significantly increasing the pile body reinforcement ratio, thus enhancing the horizontal resistance of the splicing structure. By thickening and densifying the stirrups, the resistance of the splicing structure to liquefaction horizontal forces is further enhanced. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of this utility model, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 A schematic diagram of a cross-shaped precast solid square pile splicing structure suitable for sand liquefaction zones is provided for an embodiment of this utility model. Figure 2 for Figure 1 A top view of the end of the first pile section; Figure 3 for Figure 1 A top view of the end of the second pile insertion section; Figure 4 for Figure 2 Schematic diagram of the cross-sectional structure along line A-A'; Figure 5 for Figure 2 Schematic diagram of the cross-sectional structure between B and B'; Figure 6 for Figure 3 Schematic diagram of the C-C' cross-sectional structure; Figure 7 This is a schematic diagram of the D-D' cross-sectional structure in section 3.

[0020] The following are the labeling elements in the figure: 1. Precast reinforced concrete square pile body; 2. Main reinforcement; 3. Supplementary reinforcement; 4. Horizontal reinforcement; 5. Reinforcing reinforcement; 6. End plate; 7. Channel steel; 8. Cross-shaped protrusion; 9. Square protrusion; 10. Square steel; 11. Stirrup; 101. First pile section; 102. Second pile section. Detailed Implementation

[0021] To make the technical problems, technical solutions, and beneficial effects of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present utility model and are not intended to limit the present utility model.

[0022] The terminology used in the embodiments of this utility model is for the purpose of describing particular embodiments only and is not intended to be limiting of the utility model. The singular forms “a,” “the,” and “the” used in the embodiments of this utility model and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise.

[0023] The terms "first" and "second" are used for descriptive purposes only, to distinguish objects, such as substances, from one another, and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. For example, without departing from the scope of the embodiments of this utility model, a first XX can also be referred to as a second XX, and similarly, a second XX can also be referred to as a first XX. Thus, a feature defined with "first" and "second" may explicitly or implicitly include one or more of that feature.

[0024] Please see Figures 1-7 The present invention will now describe a cross-shaped precast solid square pile splicing structure suitable for sandy soil liquefaction zones, provided by an embodiment of the present invention.

[0025] In one embodiment of this utility model, a cross-shaped precast solid square pile splicing structure suitable for sandy soil liquefaction zones includes a precast reinforced concrete square pile body 1. The precast reinforced concrete square pile body 1 includes a first pile section 101 and a second pile section 102 that can be interlocked. The first pile section 101 has a cross-shaped protrusion 8 at its insertion end, and the second pile section 102 has a cross-shaped groove that interlocks with the cross-shaped protrusion 8 at its insertion end. Both the first pile section 101 and the second pile section 102 have welded end plates 6 at their insertion ends, and the reinforcing bars 3 inside the precast reinforced concrete square pile body 1 are arranged along the entire length of the pile body.

[0026] In this embodiment, the first pile section 101 is the upper pile section, and the second pile section 102 is the lower pile section. The end of the insertion end of the second pile section 102 is provided with four protrusions, forming a cross-shaped groove between the four protrusions. These four protrusions can be square protrusions 9. Both the upper and lower pile sections are high-strength precast solid square piles. At the joint, the upper pile section has a cross-shaped convex shape, and the lower pile section has a cross-shaped concave shape. An end plate 6 is provided on the horizontal plane at the joint of the upper and lower pile sections. The size of the end plate 6 is consistent with the contact surface at the joint. The end plates 6 of the upper and lower pile sections are connected by welding.

[0027] When precasting the upper and lower pile sections, the design of the precast reinforced concrete square pile body 1 is consistent with that of traditional precast concrete pile bodies. The main reinforcement arrangement is consistent with the main reinforcement arrangement in the standard drawings, and the diameter of the auxiliary reinforcement is consistent with the auxiliary reinforcement configuration in the standard drawings. According to the reinforcement requirements in the standard drawings, the concrete material, the size and length of the main reinforcement 2 are selected according to the standard drawings and design requirements. The auxiliary reinforcement 3 is arranged along the entire length of the pile body to the end plate 6. The setting of the main reinforcement 2, auxiliary reinforcement 3 and stirrups 11 in the precast reinforced concrete square pile body 1 can refer to the conventional square pile structure design. The difference is that the auxiliary reinforcement 3 in conventional square piles does not need to be arranged along the entire length. However, in this embodiment, in order to enhance the horizontal resistance at the square pile joint, the auxiliary reinforcement 3 is lengthened and arranged along the entire length.

[0028] This utility model provides a precast reinforced concrete square pile body suitable for cross-shaped precast solid square pile splicing structure in sandy soil liquefaction zones. The pile body includes a first pile section 101 and a second pile section 102 that can be cross-shapedly inserted. The auxiliary reinforcement 3 inside the precast reinforced concrete square pile body 1 is arranged along the entire length of the pile body. The insertion ends of the first pile section 101 and the second pile section 102 can be further welded through end plates 6, which significantly improves the horizontal resistance of the precast pile splicing and enhances the shear resistance at the joint. It solves the problems of excessively long single piles of precast square piles in deep sandy soil liquefaction strata and the inability to splice piles in sandy soil liquefaction layers. The welding construction efficiency is significantly improved, and it is suitable for pile foundation engineering in earthquake-prone sandy soil liquefaction strata.

[0029] Furthermore, to enhance the structural strength of the cross-shaped protrusion 8 at the joint of the upper pile and the four square protrusions 9 of the lower pile, reinforcing bars 5 are pre-embedded in the insertion ends of the first pile 101 and the second pile 102. Transverse bars 4 are pre-embedded in the precast reinforced concrete square pile body 1 near the insertion ends of the first pile 101 and the second pile 102. The diameter of the reinforcing bars 5 is the same as that of the main reinforcing bars 2 in the precast reinforced concrete square pile body 1. The reinforcing bars 5 are welded to the transverse bars 4, and the transverse bars 4 and end plates 6 are welded to the main reinforcing bars 2. Taking a YZH450×450 solid square pile as an example, there are 12 main reinforcing bars 2 from the pile body to the transverse bars 4, and a total of 20 main reinforcing bars 2 and reinforcing bars 5 from the transverse bars 4 to the joint. The use of transverse bars 4 and reinforcing bars 5 can significantly improve the horizontal resistance at the joint without significantly increasing the overall reinforcement ratio of the pile body.

[0030] Furthermore, the horizontal reinforcement 4 is 150-300 mm long from the splice end of the first pile section 101 or the second pile section 102, and the diameter of the horizontal reinforcement 4 is the same as that of the main reinforcement 2. That is, the horizontal reinforcement 4 is set at a length of 150-300 mm from the joint of the upper and lower pile sections. The specific length is adjusted according to the pile size and is suitable for square piles of 200×200~600×600. The horizontal reinforcement 4 is connected to the main reinforcement 2 and the reinforcing reinforcement 5 by welding.

[0031] Furthermore, the stirrups 11 inside the precast reinforced concrete square pile body 1 are thickened and densified, with a diameter of 6 mm and a spacing of 50 mm. The stirrups of conventional square piles are generally 5 mm in diameter and 100 mm in spacing. In this embodiment, the stirrups 11 are thickened and densified to further enhance the horizontal resistance of the pile body and better resist liquefaction horizontal forces.

[0032] Furthermore, the height of the cross-shaped protrusion 8 and the depth of the cross-shaped groove are both 0.4L, where L is the side length of the precast reinforced concrete square pile. This ensures that the joint at the splice can effectively resist the horizontal force in the sand liquefaction zone during an earthquake.

[0033] Furthermore, the cross-shaped protrusion 8 has a cross-sectional width of L / 3-1mm, meaning that the width of the protruding cross portion of the upper pile and the recessed cross portion of the lower pile is both L / 3-1mm. This width design ensures that the upper and lower piles can be smoothly inserted, and also increases the contact area to a certain extent, thereby improving the stability of the connection.

[0034] Furthermore, a cross-shaped channel steel 7 is pre-embedded within the cross-shaped protrusion 8, and the channel steel 7 is welded to the end plate 6. The channel steel 7 can be an integral cross shape or four channel steels welded to the sides and pre-embedded in the upper pile joint. Even further, the four protrusions at the insertion end of the second pile 102 are square protrusions 9, each square protrusion 9 pre-embedded with square steel 10, and the square steel 10 is welded to the end plate 6. The thickness of the channel steel 7 and the square steel 10 can be 10-14 mm, and the thickness of the end plate 6 can be 20-24 mm, increasing according to the size of the square pile body.

[0035] In this embodiment, steel components are pre-embedded at the edge of the pile joint. Channel steel 7 is pre-embedded within the cross-shaped protrusion 8 at the pile joint of the upper pile section. End plates 6 are installed at the pile joint position of the cross-shaped protrusion 8 and on the four square recesses on its outer side. The channel steel 7 is reinforced by welding to the end plates 6 at its upper and lower positions. The end plates 6 are connected to the main reinforcement 2. End plates 6 are installed on the top of the cross-shaped recesses and the four square protrusions 9 on the outer side of the lower pile joint. Square steel 10 is pre-embedded inside the four square protrusions 9. The square steel 10 is reinforced by welding to the end plates 6 at its upper and lower positions. The end plates 6 are connected to the main reinforcement 2. The pre-embedded steel components facilitate the welding connection between the upper and lower pile sections, increasing the connection strength. They also significantly increase the horizontal resistance at the pile joint. In earthquake-prone sandy soil liquefaction zones, horizontal force is a key factor affecting pile foundation stability. The reinforcement effect of the steel components can effectively improve the horizontal resistance of the pile foundation during earthquakes.

[0036] In this embodiment, the reinforcing rib 5 and the auxiliary reinforcing rib 3 are directly welded to the pile head end plate 6, and the channel steel 7 and the square steel 10 are welded to the end plate 6 at their upper and lower ends and are embedded in the pile body. During pile fabrication, the cross-shaped protrusion of the upper pile section and the cross-shaped recess of the lower pile section must be precisely fabricated to ensure the firmness of the welds between the main reinforcing rib 2 and the transverse reinforcing rib 4, the transverse reinforcing rib 4 and the reinforcing rib 5, the auxiliary reinforcing rib 3 and the end plate 6, the reinforcing rib 5 and the end plate 6, and the square steel 10 and the channel steel 7 and the end plate 6. Simultaneously, dimensional accuracy must be guaranteed.

[0037] In this embodiment of the utility model, a cross-shaped precast solid square pile splicing structure suitable for sandy soil liquefaction zones can be welded using the following two welding methods, depending on the different sandy soil liquefaction levels and stress requirements: For pile foundations that generally only bear compressive loads, when the liquefaction level of the stratum sand is slightly liquefied, the welding position is at the transverse contact surface between the upper and lower pile sections, that is, only the transverse contact part of the protrusion and depression is welded. The end plates 6 of the upper and lower pile sections are welded, and the weld length is 4L. This welding method not only meets the stability requirements of the pile foundation under slightly liquefied conditions, but also simplifies the construction process and reduces construction costs.

[0038] For pile foundations requiring tensile and horizontal force resistance, or pile foundations with moderate sand liquefaction, in addition to welding the transverse contact surface 4L of the end plates of the upper and lower pile sections, eight vertical welds are required between the channel steel 7 and the square steel 10. These are the eight vertical contact surfaces of the square steel 10 and channel steel 7 where the upper pile protrudes and the lower pile recesses, each weld being 0.4L, for a total weld length of 7.2L. By increasing the number and length of welds, the tensile and horizontal force resistance of the pile foundation under complex working conditions can be greatly improved, ensuring the stability of the pile foundation in earthquake-prone sand liquefaction zones.

[0039] A cross-shaped precast solid square pile splicing structure suitable for sandy soil liquefaction zones according to an embodiment of this utility model can be manufactured and spliced ​​using the following methods; The main reinforcement 2, auxiliary reinforcement 3, transverse reinforcement 4, reinforcing reinforcement 5, end plate 6, channel steel 7, square steel 10, and stirrups 11 are assembled into a steel cage according to the design structure. After the steel cage is made, it is placed in a special mold for pouring and vibration to remove air bubbles, reduce pores, and make the concrete densely bonded. After this process is completed, high-temperature steam curing can be carried out. After the pile body strength reaches 100%, it can be transported to the construction site for piling.

[0040] On-site pile splicing: Place the lower pile section vertically and accurately according to the design position, then drive it into the ground using a pile driver. A static pressure pile driver is recommended to protect the pile head and prevent the protruding part of the lower pile section from tilting during splicing. Then, align the convex cross section of the upper pile section with the concave cross section of the lower pile section for splicing. For general compressive pile foundations in slightly liquefiable strata, ensure a weld length of 4L at the transverse contact points of the upper and lower pile end plates, as required. For pile foundations with pull-out and horizontal force requirements, or in strata with moderate liquefaction levels of sandy soil, after completing the transverse contact surface welding of the end plates, continue welding the eight contact lines between the channel steel at the cross protrusion of the upper pile section and the square steel at the square protrusion of the lower pile section, ensuring a weld length of 7.2L. The welding process must strictly adhere to welding process requirements to ensure welding quality. To guarantee the strength of the splice, it is recommended that the welding quality meet the requirements of a Class II weld.

[0041] Compared to the traditional method of directly welding end plates to the horizontal plane of upper and lower pile sections, the pile splicing structure of this utility model embodiment has significant advantages: through cross-shaped insertion, the horizontal resistance of the pile foundation is greatly increased without significantly increasing the reinforcement ratio of the pile body, effectively solving the limitations of excessively long precast piles or the inability to splice piles in liquefiable sand layers. Simultaneously, the reasonable design of the concave-convex cross-shaped width and the application of pre-embedded steel components facilitate insertion and further enhance the strength of the protruding structure at the joint. Furthermore, this utility model embodiment provides targeted welding methods for pile foundations with different sand liquefaction levels and stress requirements, optimizing weld dimensions. Compared to the traditional end plate welding method, this pile splicing structure of this utility model embodiment, through cross-shaped insertion and the design of pre-embedded channel steel 7, square steel 10, and the setting of transverse ribs 4 and reinforcing ribs 5, can significantly improve the horizontal resistance of precast pile splicing and enhance structural strength; it also allows for full contact at the protrusions, the weld length can be adjusted according to requirements, resulting in higher welding efficiency and stronger resistance to horizontal forces.

[0042] The above embodiments only illustrate several implementation methods of this utility model, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of this utility model patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this utility model, and these all fall within the protection scope of this utility model. Therefore, the protection scope of this utility model patent should be determined by the appended claims.

Claims

1. A cross-shaped precast solid square pile splicing structure suitable for sandy soil liquefaction zones, characterized in that, The precast reinforced concrete square pile includes a first pile section and a second pile section that can be interlocked. The first pile section has a cross-shaped protrusion at its interlocking end, and the second pile section has a cross-shaped groove at its interlocking end that interlocks with the cross-shaped protrusion. Both the first pile section and the second pile section have welded end plates at their interlocking ends. The reinforcing bars inside the precast reinforced concrete square pile are arranged along the entire length of the pile.

2. The cross-shaped precast solid square pile splicing structure suitable for sandy soil liquefaction zones as described in claim 1, characterized in that, Reinforcing bars are pre-embedded in the splice ends of the first and second pile sections. Horizontal reinforcing bars are pre-embedded in the pile body of the precast reinforced concrete square pile near the splice ends of the first and second pile sections. The diameter of the reinforcing bars is the same as that of the main reinforcing bars in the pile body of the precast reinforced concrete square pile. The reinforcing bars are welded to the horizontal reinforcing bars. The horizontal reinforcing bars and the end plates are both welded to the main reinforcing bars.

3. The cross-shaped precast solid square pile splicing structure suitable for sandy soil liquefaction zones as described in claim 2, characterized in that, The transverse reinforcement is 150-300 mm long from the splice end of the first or second pile section, and the diameter of the transverse reinforcement is the same as that of the main reinforcement.

4. The cross-shaped precast solid square pile splicing structure suitable for sandy soil liquefaction zones as described in claim 1, characterized in that, The stirrups inside the precast reinforced concrete square pile are thickened and densified, with a diameter of 6 mm and a spacing of 50 mm.

5. The cross-shaped precast solid square pile splicing structure suitable for sandy soil liquefaction zones as described in claim 1, characterized in that, The height of the cross-shaped protrusion and the depth of the cross-shaped groove are both 0.4L, where L is the side length of the precast reinforced concrete square pile.

6. The cross-shaped precast solid square pile splicing structure suitable for sandy soil liquefaction zones as described in claim 5, characterized in that, The cross-sectional width of the cross-shaped protrusion is L / 3-1mm.

7. The cross-shaped precast solid square pile splicing structure suitable for sandy soil liquefaction zones as described in claim 1, characterized in that, A cross-shaped channel steel is pre-embedded in the cross-shaped protrusion, and the channel steel is welded to the end plate.

8. A cross-shaped precast solid square pile splicing structure suitable for sandy soil liquefaction zones as described in claim 7, characterized in that... The four protrusions at the insertion end of the second pile section are square protrusions, and each square protrusion is pre-embedded with square steel, which is welded to the end plate.

9. A cross-shaped precast solid square pile splicing structure suitable for sandy soil liquefaction zones as described in claim 8, characterized in that, The thickness of both the channel steel and the square steel is 10-14 mm.

10. A cross-shaped precast solid square pile splicing structure suitable for sandy soil liquefaction zones as described in any one of claims 1-9, characterized in that, The end plate has a thickness of 20-24 mm.

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