Adjusting device and method for prestress preloading at end of horizontal internal support of deep foundation pit

Abstract

The present invention discloses an adjusting device and method for prestressing at the end of a horizontal internal support in a deep foundation pit, which includes a sleeve, an inner core rod, a force transmission steel plate, a jack and a steel wedge; the axis of the sleeve is parallel to the axis of the steel support and one end of the sleeve is bolted to the end of the steel support; a sliding cavity is defined inside the sleeve; the inner core rod is slidably connected in the sliding cavity and one end of the inner core rod extends out of the end of the sleeve away from the steel support; a limiting groove is formed on the top surface of the inner core rod; the plate surface of the force transmission steel plate is perpendicularly fixed to the extending end of the inner core rod; the cylinder body and the piston rod of the jack can respectively abut against the opposite end surfaces of the force transmission steel plate and the sleeve to apply stress and make the inner core rod slide; the steel wedge is inserted into the limiting groove after the stress application is completed to limit the sliding of the inner core rod. The present invention solves the problems that the existing adjustment method for the internal support in a deep foundation pit is inefficient, has poor accuracy, and will damage the integrity of the support structure, and it is difficult to ensure the uniform transmission and long-term effective maintenance of the prestress.

Description

Technical Field

[0001] This invention relates to the field of deep foundation pit support technology, and more specifically to an adjustment device and method for prestressing the end of a horizontal internal support in a deep foundation pit. Background Technology

[0002] In deep foundation pit engineering, a composite support system of cast-in-place piles and internal bracing is often used to ensure slope stability and the safety of the support structure during excavation. Among these, steel pipe internal bracing is widely used due to its high load-bearing capacity and relatively convenient construction. However, in actual construction, the installation and use of traditional steel bracing faces two prominent problems: First, the processing length of the steel bracing is usually determined according to the design dimensions. However, during on-site installation, due to construction errors, pile displacement, or local changes in the dimensions of the foundation pit, the actual required length of the bracing often deviates from the design length. Traditional bracing has very limited length adjustment capabilities, making it difficult to flexibly adapt to these dimensional deviations. This results in the bracing and the support system not fitting tightly together, affecting the overall stress distribution. Second, when applying prestress (pre-stressing) to improve the rigidity of the bracing and control foundation pit deformation, traditional methods (such as using jacks for jacking followed by simple welding or bolt fixing) suffer from uneven force transmission and insecure locking. Uneven prestressing can easily lead to large differences in the stress state of different parts of the bracing, while insecure locking can easily lead to relaxation under subsequent construction vibrations or load changes, resulting in prestress loss. These problems significantly reduce the effectiveness of steel supports, potentially leading to excessive deformation of the support system and affecting construction accuracy. In more serious cases, they can cause support instability, threatening the safety of deep foundation pit construction.

[0003] Therefore, how to provide an adjustment device that integrates length fine-tuning and stable, precise prestressing application and locking functions is a problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0004] In view of this, the present invention provides an adjustment device and method for prestressing the end of a horizontal internal support in a deep foundation pit, which solves the problems of low efficiency, poor accuracy, damage to the integrity of the support structure, and difficulty in ensuring uniform transmission and long-term effective maintenance of prestress in existing internal support adjustment methods for deep foundation pits.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] An adjustable device for prestressing the end of a horizontal internal support in a deep foundation pit, comprising: A sleeve, the axis of which is parallel to the axis of the steel support and one end of which is bolted to the end of the steel support; a sliding cavity is defined inside the sleeve; An inner core rod is slidably connected within the sliding cavity, with one end extending out of the sleeve away from the steel support; a limit groove is formed on the top surface of the inner core rod. A force-transmitting steel plate, the surface of which is fixed perpendicularly to the extended end of the inner core rod; The jack, wherein the cylinder and piston rod of the jack can respectively abut against the opposite end faces of the force transmission steel plate and the sleeve to apply prestress and make the inner core rod slide; A steel wedge is inserted into the limiting groove after the prestress is applied to restrict the sliding of the inner core rod.

[0007] The beneficial effects of the technical solution of this invention are that the sleeve is bolted to the support pipe of the steel support as the end of the steel support, and the length of the steel support is finely adjusted by the sliding of the inner core rod to make it suitable for the width deformation and excavation error of the deep foundation pit, thus ensuring the support accuracy of the steel support; the jack is used to apply prestress to ensure the reliable stability of the steel support, and after the prestress is applied, it is locked by steel wedges to ensure the uniform transmission of force and long-term effective maintenance.

[0008] Preferably, the number of jacks is at least two and they are symmetrical on both sides of the inner core rod. By setting multiple jacks, the length of the steel support can be adjusted by sliding the inner core rod, and prestress can be applied evenly to ensure the stable support of the steel support.

[0009] Preferably, multiple stiffening ribs are fixed to the outer peripheral wall of the extended end of the inner core rod, and one end face of each stiffening rib is welded and fixed to the face plate of the force transmission steel plate. The stiffening ribs are used to improve the stiffness and deformation capacity of the end of the inner core rod corresponding to the force transmission steel plate, preventing structural damage to the inner core rod during the application of prestress.

[0010] Preferably, the stiffening rib is a triangular plate, with its two right-angled sides welded and fixed to the face plate of the force-transmitting steel plate and the outer wall of the inner core rod, respectively. The triangular stiffening rib can significantly improve the stability of the inner core rod.

[0011] Preferably, the sleeve includes a cylinder, a support plate, and a square steel bar; both ends of the cylinder are fixed with flanges, which can be bolted to the connecting flange on the steel support or abut against the piston rod of the jack; there are multiple support plates, one end of which is fixed to the inner wall of the cylinder; the square steel bar is located in the inner cavity of the cylinder, and its outer wall is fixed to the other end of the support plate, and the inner cavity of the square steel bar is a sliding cavity. By fixing the square steel bar coaxially in the inner cavity of the cylinder to define the sliding cavity, it is ensured that the inner core rod can move linearly along the axis of the cylinder, thereby realizing the fine adjustment of the steel support length and the application of prestress.

[0012] Preferably, the length of the square steel is equal to the length of the cylinder; multiple baffles are fixed to the end face of the cylinder away from the steel support, and the panels of the baffles are welded to the end face of the square steel. The baffles are used to increase the rigidity of the cylinder and prevent deformation during the application of prestress.

[0013] Preferably, the inner core rod is a square rod, and the outer wall of the square rod slides against the inner wall of the square steel. Using a square rod adapted to the square steel ensures sliding while improving the structural rigidity and deformation resistance of the entire sleeve, ensuring stable adjustment of the steel support and application of prestress, and improving the support accuracy and strength of the steel support for the inner wall of the deep foundation pit.

[0014] Preferably, the end of the limiting groove near the force-transmitting steel plate extends out of the cylinder; there are multiple steel wedges, all of which are inserted into the limiting groove outside the cylinder, and the outer wall of the steel wedge near the cylinder is pressed tightly against the end face of the square steel. Inserting steel wedges outside the sleeve facilitates operation, effectively locks the prestress, and improves the stability of the support for the inner wall of the deep foundation pit.

[0015] Preferably, the sliding stroke of the inner core rod is not less than 800mm. This meets the dimensional deviation adjustment requirements commonly encountered in deep foundation pit construction.

[0016] This invention also provides a method for adjusting the prestressed end of a horizontal internal support in a deep foundation pit, using an adjustment device for prestressing the end of a horizontal internal support in a deep foundation pit as described above, comprising the following steps: S1. Insert the inner core rod into the sliding cavity and make the force transmission steel plate abut against the pre-embedded steel plate on the inner wall of the deep foundation pit; S2. The cylinder of the jack is brought into contact with the force transmission steel plate, and the piston rod is adjusted to bring into contact with the end face of the sleeve. S3. Activate the jack to push the inner core rod to slide and adjust the overall length of the steel support; S4. Apply prestress in stages using the jacks. Stabilize the pressure for five minutes after each stage is completed until the design prestress value is reached. S5. After the prestress is applied, insert the steel wedge into the limiting groove to ensure that the inner core rod will not slide, thereby achieving prestress locking.

[0017] As can be seen from the above technical solution, compared with the prior art, the present invention discloses an adjustment device and method for prestressing the end of the horizontal internal support in deep foundation pits. It has a reasonable structure, is easy to operate, and has reliable performance. It realizes the flexible length adjustment of the end of the horizontal internal support in deep foundation pits and the stable application and locking of prestressing, which fundamentally improves the safety and economy of the deep foundation pit support system. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, 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 embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of the adjustment device structure provided by the present invention; Figure 2 A schematic diagram of the sleeve structure provided by the present invention; Figure 3 This is a schematic diagram of the inner core rod structure provided by the present invention; Figure 4 This is a schematic diagram of the steel wedge structure provided by the present invention; Figure 5 This is a schematic diagram of the application structure of the adjustment device provided by the present invention.

[0020] Among them, 1-sleeve; 11-support plate; 12-square steel; 13-baffle; 14-cylinder body; 2-inner core rod; 21-limiting groove; 22-stiffening rib plate; 3-force transmission steel plate; 4-jack; 5-steel wedge; 6-steel support. Detailed Implementation

[0021] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0022] Existing deep foundation pit bracing technologies often rely on temporary measures such as on-site cutting and pad adjustment to accommodate length deviations. However, this method is inefficient, inaccurate, and can compromise the integrity of the bracing structure. Prestressing application also largely depends on the experience of construction workers, lacking systematic and standardized processes and specialized locking components. This makes it difficult to ensure uniform transmission and long-term effective maintenance of prestress. To address these issues in existing technologies, [the following is a separate, unrelated sentence: "participating in..."] Figure 1 To be continued Figure 5This invention discloses an adjustment device and method for prestressing the end of a horizontal internal support in a deep foundation pit, comprising a sleeve 1, an inner core rod 2, a force transmission steel plate 3, a jack 4, and a steel wedge 5; the axis of the sleeve 1 is parallel to the axis of the steel support 6, and one end of the sleeve 1 is bolted to the end of the steel support 6; a sliding cavity is defined inside the sleeve 1; the inner core rod 2 is slidably connected in the sliding cavity, and one end of the inner core rod 2 extends out of the sleeve 1 away from the end of the steel support 6; a limiting groove 21 is formed on the top surface of the inner core rod 2; the surface of the force transmission steel plate 3 is fixed perpendicularly to the extended end of the inner core rod 2; the cylinder and piston rod of the jack 4 can respectively abut against the opposite end faces of the force transmission steel plate 3 and the sleeve 1 to apply prestress and make the inner core rod 2 slide; after the prestress is applied, the steel wedge 5 is inserted into the limiting groove 21 to restrict the sliding of the inner core rod 2 and lock the prestress.

[0023] In this embodiment, the sleeve 1 includes a cylinder 14, a support plate 11, and a square steel 12; both ends of the cylinder 14 are fixed with flanges 15, which can be bolted to the connecting flange on the steel support 6 or abutted against the piston rod of the jack 4; there are multiple support plates 11, and one end of each plate is fixed to the inner wall of the cylinder 14; the square steel 12 is located in the inner cavity of the cylinder 14, and its outer wall is fixed to the other end of the support plate 11, and the inner cavity of the square steel 12 is a sliding cavity.

[0024] To further optimize the above technical solution, the inner core rod 2 is a square rod, and the outer wall of the square rod slides against the inner wall of the square steel 12.

[0025] like Figure 1 and 2 As shown, the cylinder serves as the end part of the steel support. The inner cavity of the sleeve is coaxially fixed with square steel through multiple support plates. The inner cavity of the square steel serves as the sliding cavity of the inner core rod, which can ensure the coaxiality between the inner core rod and the sleeve. The adjustment accuracy of the steel support is ensured by using the coaxial sliding of the inner core rod in the cylinder.

[0026] To further optimize the above technical solution, improve the rigidity and deformation resistance of the sleeve, and prevent damage to the sleeve during the application of prestress, the length of the square steel 12 is equal to the length of the cylinder 14; multiple baffles 13 are fixed to the end face of the cylinder 14 away from the steel support 6, and the panel of the baffle 13 is welded and fixed to the end face of the square steel 12.

[0027] To further optimize the above technical solution, improve the structural rigidity and deformation resistance of the inner core rod, and prevent the inner core rod from deforming during the application of prestress, multiple stiffening ribs 22 are fixed on the outer peripheral wall of the extended end of the inner core rod 2, and one end face of the multiple stiffening ribs 22 is welded and fixed to the panel of the force transmission steel plate 3.

[0028] In some other specific embodiments, the stiffening rib 22 is a triangular plate, and its two right-angled sides are welded and fixed to the face plate of the force transmission steel plate 3 and the outer wall of the inner core rod 2, respectively.

[0029] To further optimize the above technical solution and ensure the accuracy of the length adjustment of the inner core rod and the application accuracy of the prestress of the steel support, the number of jacks 4 is at least two and they are symmetrical on both sides of the inner core rod 2.

[0030] In this embodiment, the end of the limiting groove 21 near the force transmission steel plate 3 extends out of the cylinder 14; there are multiple steel wedges 5, and all the steel wedges 5 are inserted into the limiting groove 21 outside the cylinder 14, and the outer wall of the steel wedge 5 near the cylinder 14 is pressed and fitted with the end face of the square steel 12.

[0031] like Figure 3 As shown, the limiting groove is formed on the top surface of the inner core rod on the side corresponding to the stiffening rib. Figure 4 As shown, the steel wedge has an isosceles trapezoidal cross-section, wider at the top and narrower at the bottom, thicker at the top and thinner at the bottom. It can be inserted into the limiting groove by hammering. In actual construction, if the length of the limiting groove protruding from the sleeve is short, only one steel wedge is needed; if the length is long, multiple steel wedges are required to lock the inner core rod.

[0032] To further optimize the above technical solution, the upper part of the steel wedge, which is the widest and thickest, is greater than the width of the limiting groove.

[0033] To further optimize the above technical solution, the sliding stroke of the inner core rod 2 shall not be less than 800mm.

[0034] This embodiment provides a method for adjusting the prestressed end of a horizontal internal support in a deep foundation pit. The method involves processing various components according to the prestressed adjustment device for the horizontal internal support in a deep foundation pit described in the above technical solution, spraying an anti-corrosion layer onto the outer surface of each component, and fixing the components together by welding to ensure the flatness of the plate surface. The method includes the following steps: S1. Insert the inner core rod 2 into the inner cavity of the square steel 12 and make the force transmission steel plate 3 abut against the pre-embedded steel plate on the inner wall of the deep foundation pit. S2. Place the cylinder of the jack 4 against the force transmission steel plate 3, and adjust the piston rod to make it abut against the end face of the sleeve 1 to complete the initial positioning of the steel support 6. S3. Start the jack 4 to push the inner core rod 2 to slide and adjust the overall length of the steel support 6. The fine adjustment result is based on the tight fit between the force transmission steel plate 3 and the pre-embedded steel plate. S4. Apply prestress in four stages using jacks. Stabilize the pressure for five minutes after each stage is completed until the design prestress value is reached. S5. After the prestress is applied, insert the steel wedge 5 into the limiting groove 21 to ensure that the inner core rod 2 will not slide, thereby locking the position of the prestress and the inner core rod 2.

[0035] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the apparatus disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple; relevant parts can be referred to the method section.

[0036] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A prestress-adjustable device for the end of a horizontal internal support in a deep foundation pit, characterized in that, include: Sleeve (1), the axis of which is parallel to the axis of the steel support (6) and one end of which is bolted to the end of the steel support (6); a sliding cavity is defined inside the sleeve (1). The inner core rod (2) is slidably connected in the sliding cavity and one end of it extends out of the sleeve (1) away from the steel support (6); a limit groove (21) is provided on the top surface of the inner core rod (2). Force transmission steel plate (3), the surface of the force transmission steel plate (3) is fixed perpendicularly to the extended end of the inner core rod (2); The jack (4) has a cylinder and piston rod that can abut against the opposite end faces of the force transmission steel plate (3) and the sleeve (1) to apply prestress and make the inner core rod (2) slide. A steel wedge (5) is inserted into the limiting groove (21) after the prestress is applied to restrict the sliding of the inner core rod (2).

2. The adjustable device for prestressing the end of a horizontal internal support in a deep foundation pit according to claim 1, characterized in that, The number of jacks (4) is at least two and they are symmetrical on both sides of the inner core rod (2).

3. The adjustable device for prestressing the end of a horizontal internal support in a deep foundation pit according to claim 1, characterized in that, Multiple stiffening ribs (22) are fixed on the outer peripheral wall of the extended end of the inner core rod (2), and one end face of the multiple stiffening ribs (22) is welded and fixed to the panel of the force transmission steel plate (3).

4. The adjustable device for prestressing the end of a horizontal internal support in a deep foundation pit according to claim 3, characterized in that, The stiffening rib (22) is a triangular plate, and its two right-angled sides are welded and fixed to the panel of the force transmission steel plate (3) and the outer wall of the inner core rod (2), respectively.

5. The adjustable device for prestressing the end of a horizontal internal support in a deep foundation pit according to claim 1, characterized in that, The sleeve (1) includes a cylinder (14), a support plate (11), and a square steel (12); both ends of the cylinder (14) are fixed with flanges (15), which can be bolted to the connecting flange on the steel support (6) or abutted against the piston rod of the jack (4); there are multiple support plates (11), one end of which is fixed to the inner wall of the cylinder (14); the square steel (12) is located in the inner cavity of the cylinder (14), and its outer wall is fixed to the other end of the support plate (11), and the inner cavity of the square steel (12) is a sliding cavity.

6. The adjustable device for prestressing the end of a horizontal internal support in a deep foundation pit according to claim 5, characterized in that, The length of the square steel (12) is equal to the length of the cylinder (14); multiple baffles (13) are fixed on one end face of the cylinder (14) away from the steel support (6), and the panel of the baffle (13) is welded and fixed to the end face of the square steel (12).

7. The adjustable device for prestressing the end of a horizontal internal support in a deep foundation pit according to claim 6, characterized in that, The inner core rod (2) is a square rod, and the outer wall of the square rod slides against the inner wall of the square steel (12).

8. The adjustable device for prestressing the end of a horizontal internal support in a deep foundation pit according to claim 7, characterized in that, The limiting groove (21) extends out of the cylinder (14) at one end near the force transmission steel plate (3); there are multiple steel wedges (5), and all the steel wedges (5) are inserted into the limiting groove (21) outside the cylinder (14), and the outer wall of the steel wedge (5) near the cylinder (14) is pressed against the end face of the square steel (12).

9. The adjustable device for prestressing the end of a horizontal internal support in a deep foundation pit according to claim 1, characterized in that, The sliding stroke of the inner core rod (2) is not less than 800 mm.

10. A method for adjusting the prestress at the end of a horizontal internal support in a deep foundation pit, characterized in that, The adjustment device for prestressing the end of a horizontal internal support in a deep foundation pit, as described in any one of claims 1 to 9, includes the following steps: S1. Insert the inner core rod (2) into the sliding cavity and make the force transmission steel plate (3) abut against the pre-embedded steel plate on the inner wall of the deep foundation pit; S2. The cylinder of the jack (4) is brought into contact with the force transmission steel plate (3), and the piston rod is adjusted to bring into contact with the end face of the sleeve (1). S3. Start the jack (4) to push the inner core rod (2) to slide and adjust the overall length of the steel support (6); S4. Apply prestress in stages using the jack (4). Stabilize the pressure for five minutes after each stage is completed until the design prestress value is reached. S5. After the prestress is applied, insert the steel wedge (5) into the limiting groove (21) to ensure that the inner core rod (2) will not slide, thereby achieving prestress locking.

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