Construction method of deep foundation pit support column

Abstract

The application provides a construction method and a penetrating method of a deep foundation pit supporting stand column, the stand column pile reinforcement cage and the concrete square pile are welded into an integrated structure at the orifice of a pile hole, and then are lowered into the pile hole together, and then the stand column pile reinforcement cage and the concrete square pile are sent into the preset position of the pile hole by using a pile sender, so that the problem of difficult positioning of the stand column pile reinforcement cage in the hole can be effectively solved; the position of the pile sender can be controlled on the ground, so that the construction quality of the stand column pile and the construction precision of the concrete square pile can be improved.

Description

Technical Field

[0001] This invention relates to the field of engineering construction technology, and more specifically, to a construction method for deep foundation pit support columns. Background Technology

[0002] Common deep foundation pit retaining structures for subway stations include retaining piles, horizontal supports, and temporary columns. These support systems are often abandoned or dismantled after station construction, resulting in significant waste. To address this, in prefabricated composite subway stations, precast concrete square piles are used as deep foundation pit support columns. The foundation uses bored piles as column piles, with the precast concrete square piles anchored into these columns. These precast concrete square piles are then encased in cast-in-place concrete to serve as the station's permanent structural columns. This improves the utilization rate of temporary structures and reduces construction costs.

[0003] The precast concrete square piles also serve as permanent structures. The pile body has numerous embedded parts in the concrete longitudinal beams and support nodes of the station, which requires high construction precision.

[0004] The current construction method involves first lowering the steel reinforcement cage of the column pile and then pouring concrete before inserting the precast concrete square pile. On the one hand, it is difficult to position the steel reinforcement cage of the column pile in the hole, which makes it impossible to guarantee the construction quality of the column pile. On the other hand, the precast concrete square pile is located below the ground, and it is difficult to control the accuracy of its plane position, verticality and elevation. Summary of the Invention

[0005] In view of the above problems, the purpose of this invention is to provide a construction method for deep foundation pit support columns, so as to solve the problems of the existing construction method of first lowering the column pile reinforcement cage and pouring concrete and then inserting the precast concrete square pile, which has the problems of difficulty in positioning the column pile reinforcement cage in the hole and the inability to guarantee the construction quality of the column pile; and the problem that the precast concrete square pile is located below the ground, and the accuracy of its plane position, verticality and elevation is difficult to control.

[0006] This invention provides a construction method for deep foundation pit support columns, comprising the following steps:

[0007] S1. The prefabricated column pile reinforcement cage is hoisted into the pre-constructed pile hole, and after leaving a first preset length above the column pile reinforcement cage, it is placed above the pile hole.

[0008] S2. Lift the precast concrete square pile so that the lower end of the concrete square pile is inserted into the column pile reinforcement cage through the upper entrance. When the concrete square pile is inserted into the column pile reinforcement cage to the first preset position, use metal parts to weld and fix the metal plates embedded around the pile body of the concrete square pile to the column pile reinforcement cage.

[0009] S3. The concrete square pile and the column pile reinforcement cage, which are fixed as one piece, are lowered together in the pile hole, and after leaving a second preset length above the concrete square pile, they are placed above the pile hole.

[0010] S4. Fix the bottom bolt through hole of the prefabricated pile driver to the pre-embedded connecting bolt at the top of the concrete square pile, so that the pile driver, the concrete square pile and the column pile reinforcement cage form an integral structure to be lowered.

[0011] S5. Place a portal-shaped beam frame at the pile hole, and lower the overall structure to be lowered through the inside of the beam frame into the pile hole, so that the column pile reinforcement cage and the concrete square pile are lowered to the second preset position of the pile hole. Fix horizontal plates on both sides of the pile driver, and place the bottom end of the horizontal plate on the beam frame.

[0012] S6. Concrete is poured between the steel reinforcement cage of the column pile and the concrete square pile, which is lowered to the second preset position. After the concrete solidifies, the pile hole is backfilled to complete the construction of the deep foundation pit support column.

[0013] Furthermore, a preferred embodiment is that the step of hoisting the prefabricated column pile reinforcement cage into the pre-constructed pile hole, and then placing the column pile reinforcement cage above the pile hole after leaving a first preset length above it, includes:

[0014] A crane is used to lift the steel reinforcement cage of the column pile to the pile hole, so that the lower end of the steel reinforcement cage of the column pile is lowered into the inside of the pile hole;

[0015] When the length of the upper part of the column pile reinforcement cage outside the pile hole reaches the first preset length, the column pile reinforcement cage is placed at the pile hole by passing reinforcement bars horizontally above the column pile reinforcement cage.

[0016] Furthermore, a preferred embodiment includes the following: hoisting the precast concrete square pile so that its lower end is inserted into the column pile reinforcement cage through the upper inlet;

[0017] A steel bar is horizontally inserted into a pre-set through hole on the upper part of the concrete square pile.

[0018] The crane hook is attached to the steel bar, and the concrete square pile is lifted from a horizontal position to a vertical position, so that the lower end of the concrete square pile is inserted into the column pile reinforcement cage through the upper entrance of the column pile reinforcement cage.

[0019] Furthermore, a preferred embodiment is that, during the process of lowering the integrally fixed concrete square pile and the reinforcing cage of the column pile together into the pile hole, and leaving a second predetermined length above the concrete square pile, it is placed above the pile hole.

[0020] The through hole of the concrete square pile is preset at the pile body position from the top of the pile down to the second preset length;

[0021] When the reinforced cage of the concrete square pile and the column pile, which are fixed as one piece, is lowered into the pile hole to leave a second preset length above the concrete square pile, the concrete square pile is supported above the pile hole by the steel bar.

[0022] Furthermore, a preferred embodiment is that, when the concrete square pile is inserted into the first preset position of the column pile reinforcement cage, during the process of welding and fixing the metal plates pre-embedded around the pile body of the concrete square pile to the column pile reinforcement cage using metal components,

[0023] The metal component is a reinforcing bar; one end of the reinforcing bar is welded to the metal plate, and the other end of the reinforcing bar is welded to the reinforcing cage of the column pile.

[0024] Furthermore, in a preferred embodiment, the pile driver includes a pile driver body made of H-beams or I-beams and a horizontal steel plate fixed to the bottom of the pile driver body; the area of ​​the horizontal steel plate is equal to the area of ​​the top cross-section of the concrete square pile and the same shape; the horizontal steel plate is provided with bolt through holes corresponding to the positions of the connecting bolts, and the bolt through holes are adapted to the connecting bolts; a hoisting hole is provided on the upper part of the pile driver body.

[0025] Furthermore, a preferred embodiment is that, during the process of lowering the integral structure to be lowered through the interior of the crossbeam frame into the pile hole, so that the column pile reinforcement cage and the concrete square pile are lowered to the second preset position of the pile hole, horizontal plates are fixed on both sides of the pile driver, and the bottom end of the horizontal plates rests on the crossbeam frame,

[0026] The planar position of the pile driver is adjusted by the crossbeam frame to control the planar position of the concrete square pile and the steel reinforcement cage of the column pile.

[0027] Make elevation marks on both sides of the pile driver corresponding to the top of the crossbeam frame, and fix a horizontal plate at the elevation marks.

[0028] In addition, a preferred embodiment is that the horizontal plate is a steel plate; the steel plate is welded and fixed to the pile driver.

[0029] Furthermore, a preferred embodiment is that during the process of pouring concrete between the steel reinforcement cage of the column pile and the concrete square pile, which is lowered to the second preset position,

[0030] Concrete is poured between the steel reinforcement cage of the column pile and the concrete square pile using a conduit with a diameter of 150-200 mm.

[0031] Furthermore, a preferred embodiment is that the crossbeam frame is welded from three sections of square steel.

[0032] As can be seen from the above technical solution, the construction method for deep foundation pit support columns provided by the present invention welds the column pile reinforcement cage and the concrete square pile into an integral structure at the opening of the pile hole, and then lowers them together into the pile hole. Then, a pile driver is used to send the column pile reinforcement cage and the concrete square pile into the preset position of the pile hole. This can effectively solve the problem of difficulty in positioning the column pile reinforcement cage in the hole. The position of the pile driver can be controlled on the ground, thus improving the construction quality of the column pile and the construction accuracy of the concrete square pile.

[0033] To achieve the foregoing and related objectives, one or more aspects of the invention include the features that will be described in detail below. The following description and accompanying drawings illustrate certain exemplary aspects of the invention. However, these aspects indicate only a few of the various ways in which the principles of the invention can be used. Furthermore, the invention is intended to encompass all such aspects and their equivalents. Attached Figure Description

[0034] Other objects and results of the invention will become more apparent and readily understood with reference to the following description taken in conjunction with the accompanying drawings. In the drawings:

[0035] Figure 1 A flowchart illustrating a construction method for deep foundation pit support columns according to an embodiment of the present invention;

[0036] Figure 2 This is a top view of the steel reinforcement cage and concrete square pile according to an embodiment of the present invention.

[0037] Figure 3 This is a schematic diagram of the axial structure of the concrete square pile and the pile driver according to an embodiment of the present invention;

[0038] Figure 4 An elevation view of the welding of the concrete square pile and the column pile reinforcement cage according to an embodiment of the present invention.

[0039] Figure 5 This is an elevation view of the connection between the concrete square pile and the pile driver according to an embodiment of the present invention;

[0040] Figure 6This is an isometric view of the connection between the concrete square pile and the pile driver according to an embodiment of the present invention;

[0041] Figure 7 This is an elevation view of the installation and positioning of the concrete square pile and column pile reinforcement cage according to an embodiment of the present invention.

[0042] Figure 8 This is a top view of the installation and positioning of the concrete square pile and column pile reinforcement cage according to an embodiment of the present invention.

[0043] In the attached drawings, 1-reinforcing cage for column pile, 2-pile hole, 3-concrete square pile, 4-column pile, 5-pile driver, 6-crane, 7-metal plate, 8-through hole, 9-steel bar, 10-connecting bolt, 11-bolt through hole, 12-pile driver body, 13-horizontal steel plate, 14-lifting hole, 15-beam frame, 16-horizontal horizontal plate, 17-guide pipe, 18-steel casing.

[0044] In all the accompanying drawings, the same reference numerals indicate similar or corresponding features or functions. Detailed Implementation

[0045] In the following description, numerous specific details are set forth for illustrative purposes and to provide a thorough understanding of one or more embodiments. However, it will be apparent that these embodiments may also be implemented without these specific details.

[0046] In response to the aforementioned problems in the existing technology, which involves first lowering the steel reinforcement cage of the column pile and then pouring concrete before inserting the precast concrete square pile, there are difficulties in positioning the steel reinforcement cage of the column pile in the hole, making it impossible to guarantee the construction quality of the column pile; and the precast concrete square pile is located below the ground, making it difficult to control the accuracy of its plane position, verticality and elevation. Therefore, a construction method for supporting columns in deep foundation pits is proposed.

[0047] The specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0048] To illustrate the construction method of the deep foundation pit support column provided by the present invention, Figure 1 The flowchart of a construction method for a deep foundation pit support column according to an embodiment of the present invention is shown; Figure 2 The top view of the steel reinforcement cage and concrete square pile according to an embodiment of the present invention is shown. Figure 3 The axial structure of a concrete square pile and a pile driver according to an embodiment of the present invention is shown; Figure 4 The elevation structure of the concrete square pile and the column pile reinforcement cage welded according to an embodiment of the present invention is shown. Figure 5 The elevation structure connecting the concrete square pile and the pile driver according to an embodiment of the present invention is shown. Figure 6 The axial structure connecting the concrete square pile and the pile driver according to an embodiment of the present invention is shown; Figure 7 The elevation structure of the concrete square pile and column pile reinforcement cage installation in place according to an embodiment of the present invention is shown. Figure 8 The diagram shows a top view of the installation and positioning of the concrete square pile and column pile reinforcement cage according to an embodiment of the present invention.

[0049] like Figures 1 to 8 As shown in the figure, the construction method for deep foundation pit support columns provided by the present invention includes the following steps:

[0050] S1. The prefabricated column pile reinforcement cage 1 is hoisted into the pre-constructed pile hole 2, and after leaving a first preset length above the column pile reinforcement cage 2, it is placed above the pile hole 2.

[0051] Specifically, the location of the pile holes, i.e., the designed pile positions, is determined according to the on-site construction requirements. Holes are drilled at these designed positions, ensuring that the verticality, depth, and diameter of the holes meet design and specification requirements, thus obtaining pile hole 2. The column pile reinforcement cage 1 and the concrete square pile 3 are then placed in pile hole 2, and after concrete pouring and solidification, pile hole 2 is backfilled to obtain the permanent structural column, i.e., column pile 4. The first preset length can be determined according to on-site construction requirements, as long as it ensures that the concrete square pile 3 is inserted into the column pile reinforcement cage 2 to the preset position, and that welding between the two can be performed on the ground. This facilitates the welding operation between the concrete square pile 3 and the column pile reinforcement cage 2, ensuring smooth welding.

[0052] The existing technology involves first lowering the reinforcing cage of the column pile and pouring concrete, and then inserting the concrete square pile. On the one hand, it is difficult to position the reinforcing cage of the column pile in the hole, which cannot guarantee the construction quality of the column pile. On the other hand, the concrete square pile is located below the ground, and its plane position, verticality and elevation accuracy are difficult to control. Based on the above-mentioned defects of the existing technology, the present invention provides a construction method for deep foundation pit support columns. By first welding the reinforcing cage 1 of the column pile and the concrete square pile 3 at the pile hole 2, they are lowered together. The position of the pile driver 5 is controlled on the ground with the help of the pile driver 5. When it is lowered to the preset position of the pile hole 2, concrete is poured. This solves the above-mentioned defects of the existing technology and effectively improves the construction quality of the column pile and the construction accuracy of the precast concrete square pile.

[0053] As a preferred embodiment of the present invention, the prefabricated column pile reinforcement cage 1 is hoisted into the pre-constructed pile hole 2, and after leaving a first preset length above the column pile reinforcement cage 1, it is placed above the pile hole 2, including:

[0054] Crane 6 is used to lift the column pile reinforcement cage 1 to the pile hole 2, so that the lower end of the column pile reinforcement cage 1 is lowered into the pile hole 2;

[0055] When the length of the upper part of the column pile reinforcement cage 1 outside the pile hole 2 reaches the first preset length, the column pile reinforcement cage 1 is placed at the pile hole 2 by passing reinforcement bars horizontally through the upper part of the column pile reinforcement cage 1.

[0056] Specifically, according to the design drawings and construction requirements, the column pile reinforcement cage 1 and pile driver 5 are manufactured in the processing plant, and the prefabrication of concrete square piles 3 is completed. The column pile reinforcement cage 1 is hoisted into the pile hole 2 by a crane 6, so that the lower end of the column pile reinforcement cage 1 is inserted into the pile hole 2, and the upper part of the column pile reinforcement cage 1 is left with a first preset length for inserting and fixing the concrete square pile 3. There are various ways to place the column pile reinforcement cage 1 in the pile hole 2. For example, a horizontal bar can be placed at the pile hole 2, and then hooks can be installed on the column pile reinforcement cage 1 or it can be fixed to the horizontal bar by tying ropes. In this embodiment, the preferred method is to pass steel bars or rod-shaped structural members horizontally through the cage body of the column pile reinforcement cage 1, and then erect the steel bars or rod-shaped structural members at the opening of the pile hole 2 so that the column pile reinforcement cage 1 is placed at the pile hole 2. In practical applications, there can be many alternative methods. This embodiment of the invention does not limit the specific method of placement. Those skilled in the art can use appropriate means to place the column pile reinforcement cage 1 at the pile hole 2 according to the actual site conditions.

[0057] S2. Lift the precast concrete square pile 3 so that the lower end of the concrete square pile 3 is inserted into the column pile reinforcement cage 1 through the upper entrance. When the concrete square pile 3 is inserted into the column pile reinforcement cage 1 to the first preset position, use metal parts to weld and fix the metal plate 7 embedded around the pile body of the concrete square pile 3 to the column pile reinforcement cage 1.

[0058] Specifically, such as Figure 4 As shown, a crane is used to lift the concrete square pile 3, and then the lower end of the concrete square pile 3 is inserted into the column pile reinforcement cage 1 through the upper entrance. When the concrete square pile 3 is inserted into the column pile reinforcement cage 1 to the first preset position, metal plates 7 embedded around the pile body of the concrete square pile 3 are welded and fixed to the column pile reinforcement cage 1 using metal parts. The concrete square pile 3 is lifted using an externally installed lifting device, for example, by fixing a useful lifting rope to the top of the concrete square pile 3. A through hole 8 is pre-drilled in the upper part of the concrete square pile 3, and a steel bar is inserted laterally into the through hole to assist the crane in lifting. The present invention does not particularly limit the lifting method of the concrete square pile 3, as long as it can be successfully lifted and inserted into a suitable position in the column pile reinforcement cage 1.

[0059] As a preferred embodiment of the present invention, the precast concrete square pile 3 is lifted so that the lower end of the concrete square pile 3 is inserted into the column pile reinforcement cage 1 through the upper entrance of the column pile reinforcement cage 1, including:

[0060] A steel bar 9 is horizontally inserted into the pre-set through hole 8 on the upper part of the concrete square pile 3.

[0061] The hook of the crane 6 is attached to the steel bar 9, and the concrete square pile 3 is lifted from a horizontal position to a vertical position, so that the lower end of the concrete square pile 3 is inserted into the column pile reinforcement cage 1 through the upper entrance of the column pile reinforcement cage 1.

[0062] As a preferred embodiment of the present invention, when the concrete square pile 3 is inserted into the first preset position of the column pile reinforcement cage 1, the metal plates 7 embedded around the pile body of the concrete square pile 3 are welded and fixed to the column pile reinforcement cage 1 using metal parts.

[0063] Metal component 7 is a reinforcing bar; one end of the reinforcing bar is welded to metal plate 7, and the other end of the reinforcing bar is welded to column pile reinforcing cage 1.

[0064] Specifically, during the prefabrication of the concrete square pile 3, a through hole 8 is reserved 1m away from the pile top. Metal plates 7 are pre-embedded around the portion of the pile body anchored into the column pile reinforcement cage 1. The metal plates 7 can be iron, copper, or steel plates. In this embodiment of the invention, steel plates are preferred. Four connecting bolts 10 are pre-embedded at the pile top. After acceptance, the pile is transported to the site. When the concrete square pile 3 is anchored into the preset position within the column pile reinforcement cage 1, the metal plates 7 pre-embedded around the pile body of the concrete square pile 3 are welded and fixed to the column pile reinforcement cage 1 using metal components. This forms an integral structure between the column pile reinforcement cage 1 and the concrete square pile 3, making it easier to position the column pile reinforcement cage 1 within the pile hole 2.

[0065] S3. The concrete square pile 3, which is fixed as one piece, and the steel cage 1 of the column pile are lowered together in the pile hole 2. After leaving a second preset length above the concrete square pile 3, it is placed above the pile hole 2.

[0066] Specifically, the second preset length can be determined according to the actual construction situation. Its function is to make the top of the concrete square pile 3 protrude from the pile hole 2 at a certain height, so as to facilitate the connection between the pile driver 5 and the top of the concrete square pile 3.

[0067] As a preferred embodiment of the present invention, after the concrete square pile 3 and the column pile reinforcement cage 1, which are fixed as one piece, are lowered together in the pile hole 2, and after leaving a second preset length above the concrete square pile 3, it is placed above the pile hole 2.

[0068] The through hole 8 of the concrete square pile 3 is pre-set at the pile body position from the top of the pile down to the second pre-set length;

[0069] When the concrete square pile 3, which is fixed as one piece, and the column pile reinforcement cage 1 are lowered into the pile hole 2, leaving a second preset length above the concrete square pile 3, the concrete square pile 3 is supported above the pile hole 2 by the steel rod 9.

[0070] Specifically, the perforation 8 is pre-set at a position on the pile body from the top of the pile down to the second pre-set length. It can be used to hoist the concrete square pile 3 by passing a steel bar 9 through it, and it can also be used to support the concrete square pile 3 and the column pile reinforcement cage 1, which are fixed as one piece, in the pile hole 2 and lower them together to a suitable position, with the steel bar 9 supporting them above the pile hole 2. The second pre-set length is preferably 1 meter.

[0071] S4. Fix the bottom bolt through hole 11 of the prefabricated pile driver 5 to the pre-embedded connecting bolt 10 at the top of the concrete square pile 3, so that the pile driver 5, the concrete square pile 3 and the column pile reinforcement cage 1 form an integral structure to be lowered.

[0072] Specifically, such as Figure 3 , Figure 5 as well as Figure 6 As shown, the pile driver 5 is connected to the concrete square pile 3 and the column pile reinforcement cage 1 as a whole by connecting bolts 10. Then, the concrete square pile 3 and the column pile reinforcement cage 1 are placed into the pile hole 2 by using the pile driver 5. Therefore, the plane position, verticality and elevation of the concrete square pile 3 and the column pile reinforcement cage 1 can be controlled by adjusting the plane position of the pile driver 5 on the ground.

[0073] As a preferred embodiment of the present invention, the pile driver includes a pile driver body 12 made of H-beams or I-beams and a horizontal steel plate 13 fixed at the bottom of the pile driver body 12; the area of ​​the horizontal steel plate 13 is equal to the area of ​​the top cross section of the concrete square pile 3 and the same shape; a bolt through hole 11 corresponding to the position of the connecting bolt 10 is provided on the horizontal steel plate 13, and the bolt through hole 11 is adapted to the connecting bolt 10; a hoisting hole 14 is provided on the upper part of the pile driver body 12.

[0074] Specifically, such as Figure 3 As shown, the pile driver 5 is a steel pile driver, which is sturdy and durable. A horizontal steel plate 13 is welded to the bottom of the pile driver body 12 for fixed connection with the pre-embedded connecting bolts 10 at the top of the concrete square pile 3. The area of ​​the horizontal steel plate 13 is equal to the area of ​​the top cross-section of the concrete square pile 3, and their identical shape ensures better fit between the two. By adjusting the plane position, verticality, and elevation of the pile driver 5 on the ground, the concrete square pile 3 and the column pile reinforcement cage 1 below can be better controlled. The length of the pile driver 5 is the ground elevation of the pile position - the top elevation of the concrete square pile 3 + 1m, and the top of the pile driver 5 has a lifting hole 14.

[0075] S5. Place the portal frame 15 at the pile hole 2, and lower the whole structure to be lowered through the inside of the frame 15 into the pile hole 2, so that the column pile reinforcement cage 1 and the concrete square pile 3 are lowered to the second preset position of the pile hole 2. Fix the horizontal plate 16 on both sides of the pile driver 5, and place the bottom end of the horizontal plate 16 on the frame 15.

[0076] Specifically, the crossbeam frame 15 is made of three sections of square steel welded into a "door" shape. The net distance between the middle of the crossbeam is slightly larger than the size of the main body of the pile driver 5. The crossbeam frame 15 plays the role of supporting the support point and controlling the accuracy. Its strength can meet the requirements of bearing the structural weight.

[0077] As a preferred embodiment of the present invention, during the process of lowering the overall structure to be lowered through the interior of the crossbeam frame 15 into the pile hole 2, so that the column pile reinforcement cage 1 and the concrete square pile 3 are lowered to the second preset position of the pile hole 2, horizontal plates 16 are fixed on both sides of the pile driver 5, and the bottom end of the horizontal plates 16 is placed on the crossbeam frame 15,

[0078] The planar position of the pile driver 5 is adjusted by the crossbeam frame 15 to control the planar position of the concrete square pile 3 and the column pile reinforcement cage 1.

[0079] Make elevation marks on both sides of the pile driver 5 corresponding to the top of the crossbeam frame 15, and fix the horizontal plate 16 at the elevation marks.

[0080] Specifically, since the crossbeam frame 15 is placed flat at the pile hole 2, and the pile driver 5 passes vertically through the interior of the crossbeam frame 15, the two are perpendicular. By using the crossbeam frame 15 as the horizontal plane, the planar position of the pile driver 5 can be adjusted to determine the planar position of the concrete square pile 3 and the column pile reinforcement cage 1. By marking the elevation on both sides of the pile driver 5 at the top of the crossbeam frame 15, the lowering elevation of the column pile reinforcement cage 1 and the concrete square pile 3 can be determined. It is only necessary to know the height of the column pile reinforcement cage 1, the concrete square pile 3, the pile driver 5, and the pile hole 2 in advance.

[0081] As a preferred embodiment of the present invention, the horizontal plate 16 is a steel plate; the steel plate is welded and fixed on the pile driver 5.

[0082] As a preferred embodiment of the present invention, the crossbeam frame 15 is welded from three sections of square steel.

[0083] Specifically, the planar position of the pile driver 5 is adjusted by the crossbeam frame 15 to control the planar position of the precast concrete square pile 3 and the reinforcing cage 1 and lower it to the design elevation. At this time, marks are made on both sides of the pile driver 5 corresponding to the top of the crossbeam frame 15. Four steel plates are fully welded to the marked positions on both sides of the pile driver 5 and placed on the crossbeam frame 15. The planar position, verticality and elevation of the concrete square pile 3 and the reinforcing cage 1 can be accurately controlled.

[0084] S6. Pour concrete between the steel cage 1 and the concrete square pile 3, which are lowered to the second preset position. After the concrete solidifies, backfill the pile hole 2 to complete the construction of the deep foundation pit support column.

[0085] As a preferred embodiment of the present invention, during the process of pouring concrete between the steel reinforcement cage 1 of the column pile and the concrete square pile 3, which is lowered to the second preset position,

[0086] Concrete is poured between the steel reinforcement cage of the column pile and the concrete square pile using a conduit with a diameter of 150-200 mm.

[0087] After the concrete square pile 3 and the column pile reinforcement cage 1 are in place, the column pile concrete is poured. Since the gap between the column pile reinforcement cage 1 and the concrete square pile 3 is too small, a guide pipe 17 with a diameter of 150-200mm can be used to pour the concrete. After the concrete solidifies, the pile hole 2 is backfilled.

[0088] To better illustrate the construction method of the deep foundation pit support column provided by the present invention, the following specific embodiments are provided.

[0089] Example 1

[0090] According to the design drawings and construction requirements, the reinforcing cage 1 for the column piles and the pile driver 5 are fabricated in the processing plant, and the prefabrication of the concrete square piles 3 is completed. During the prefabrication of the concrete square piles 3, a through hole 8 is reserved 1m from the pile top. Steel plates are pre-embedded around the portion of the pile body anchored into the column pile, and four connecting bolts 10 are pre-embedded at the pile top. After acceptance, the piles are transported to the site. Based on the designed height of the concrete square pile 3 from the ground, the corresponding pile driver 5 is fabricated. The pile driver 5 is composed of H-beams or I-beams welded to steel plates. Bolt through holes 11 are opened at the corresponding positions of the connecting bolts 10 at the pile top on the bottom steel plate. The length of the pile driver 5 is the ground elevation of the pile location minus the top elevation of the concrete square pile 3 + 1m. A lifting hole 14 is provided at the top of the pile driver 5. The crossbeam frame 15 is welded from three sections of square steel into a "door" shape. The clear distance between the middle sections of the crossbeam frame 15 is slightly larger than the size of the pile driver 5. The crossbeam frame 15 serves to support the points and control accuracy, and its strength is sufficient to bear the structural weight requirements.

[0091] When drilling at the designed pile location, the verticality, depth, and diameter of the borehole should meet the design and specification requirements.

[0092] The column pile reinforcement cage 1 is lifted into the hole by a crane and placed at the hole opening, with a portion of the column pile reinforcement cage 1 reserved above the hole opening;

[0093] The concrete square pile 3 is lifted from a horizontal position to a vertical position by a crane using a pre-reserved through hole 8 and a steel bar 9. The pile body is then moved above the hole and inserted into the designed position inside the column pile reinforcement cage 1. The column pile reinforcement cage 1 is welded to the pre-embedded steel plates around the pile body using steel bars. Before welding, the relative positions of the center of the concrete square pile 3 and the center of the column pile reinforcement cage 1 should be fixed.

[0094] After the steel reinforcement cage 1 of the column pile is welded to the concrete square pile 3, they are lowered together until the pre-drilled steel bar 9 is left in the pile body. The concrete square pile 3 is then placed on the crossbeam frame 15 on the steel casing 18. The pre-processed pile driver 5 is then lifted to the top of the concrete square pile 3 by a crane and connected to the four connecting bolts 10.

[0095] After the pile driver 5 is connected to the concrete square pile 3, the supporting steel rod 9 is pulled out, and the pile driver 5, the concrete square pile 3 and the column pile reinforcement cage 1 are lowered as a whole. During the lowering process, the planar position of the pile driver 5 is adjusted by the crossbeam frame 15 to control the planar position of the concrete square pile 3 and the column pile reinforcement cage 1 and lower it to the design elevation. At this time, marks are made on both sides of the pile driver 5 corresponding to the top of the crossbeam frame 15. Four steel plates are fully welded to the marked positions on both sides of the pile driver 5 and supported on the crossbeam frame 15. The planar position, verticality and elevation of the concrete square pile 3 and the column pile reinforcement cage 1 can be accurately controlled.

[0096] After the concrete square pile 3 and the column pile reinforcement cage 1 are in place, the column pile concrete is poured. Since the gap between the column pile reinforcement cage 1 and the precast concrete square pile 3 is too small, a guide pipe 17 with a diameter of 150-200mm can be used to pour the concrete. After the concrete solidifies, the pile hole 2 is backfilled.

[0097] As can be seen from the above specific embodiments, the construction method for deep foundation pit support columns provided by the present invention, by welding the column pile reinforcement cage and the concrete square pile into an integral structure at the opening of the pile hole and lowering them together into the pile hole, and then using a pile driver to send the column pile reinforcement cage and the concrete square pile into the preset position of the pile hole, can effectively solve the problem of difficulty in positioning the column pile reinforcement cage in the hole; the position of the pile driver can be controlled on the ground, thus improving the construction quality of the column pile and the construction accuracy of the concrete square pile.

[0098] The construction method for deep foundation pit support columns according to the present invention has been described above by way of example with reference to the accompanying drawings. However, those skilled in the art should understand that various modifications can be made to the construction method for deep foundation pit support columns according to the present invention without departing from the scope of the invention. Therefore, the scope of protection of the present invention should be determined by the contents of the appended claims.

Claims

1. A construction method for a deep foundation pit support column, characterized in that, Includes the following steps: S1. The prefabricated column pile reinforcement cage is hoisted into the pre-constructed pile hole, and after leaving a first preset length above the column pile reinforcement cage, it is placed above the pile hole. S2. Lift the precast concrete square pile so that the lower end of the concrete square pile is inserted into the column pile reinforcement cage through the upper entrance. When the concrete square pile is inserted into the column pile reinforcement cage to the first preset position, use metal parts to weld and fix the metal plates embedded around the pile body of the concrete square pile to the column pile reinforcement cage. S3. The concrete square pile and the column pile reinforcement cage, which are fixed as one piece, are lowered together in the pile hole, and after leaving a second preset length above the concrete square pile, they are placed above the pile hole. S4. Fix the bottom bolt through hole of the prefabricated pile driver to the pre-embedded connecting bolt at the top of the concrete square pile, so that the pile driver, the concrete square pile and the column pile reinforcement cage form an integral structure to be lowered. S5. A portal-shaped crossbeam frame is placed at the pile hole, and the entire structure to be lowered is passed through the inside of the crossbeam frame and lowered into the pile hole, so that the column pile reinforcement cage and the concrete square pile are lowered to the second preset position of the pile hole. Horizontal plates are fixed on both sides of the pile driver, and the bottom end of the horizontal plates rests on the crossbeam frame; wherein... The horizontal plate is a steel plate; the steel plate is welded and fixed to the pile driver. The crossbeam frame is welded from three sections of square steel. During the process of lowering the overall structure to be lowered through the interior of the crossbeam frame into the pile hole, so that the column pile reinforcement cage and the concrete square pile are lowered to the second preset position of the pile hole, horizontal plates are fixed on both sides of the pile driver, and the bottom end of the horizontal plates rests on the crossbeam frame. The planar position of the pile driver is adjusted by the crossbeam frame to control the planar position of the concrete square pile and the steel reinforcement cage of the column pile. Make elevation marks on both sides of the pile driver corresponding to the top of the crossbeam frame, and fix a horizontal plate at the elevation marks; S6. Concrete is poured between the steel reinforcement cage of the column pile and the concrete square pile, which is lowered to the second preset position. After the concrete solidifies, the pile hole is backfilled to complete the construction of the deep foundation pit support column.

2. The construction method for deep foundation pit support columns according to claim 1, characterized in that, The step of hoisting the prefabricated column pile reinforcement cage into the pre-constructed pile hole, and placing the column pile reinforcement cage above the pile hole after leaving a first preset length above it includes: A crane is used to lift the steel reinforcement cage of the column pile to the pile hole, so that the lower end of the steel reinforcement cage of the column pile is lowered into the inside of the pile hole; When the length of the upper part of the column pile reinforcement cage outside the pile hole reaches the first preset length, the column pile reinforcement cage is placed at the pile hole by passing reinforcement bars horizontally above the column pile reinforcement cage.

3. The construction method for deep foundation pit support columns according to claim 1, characterized in that, The step of lifting the precast concrete square pile so that the lower end of the concrete square pile is inserted into the column pile reinforcement cage through the upper entrance of the column pile reinforcement cage includes: A steel bar is horizontally inserted into a pre-set through hole on the upper part of the concrete square pile. The crane hook is attached to the steel bar, and the concrete square pile is lifted from a horizontal position to a vertical position, so that the lower end of the concrete square pile is inserted into the column pile reinforcement cage through the upper entrance of the column pile reinforcement cage.

4. The construction method for deep foundation pit support columns according to claim 3, characterized in that, During the process of lowering the concrete square pile and the reinforcing cage of the column pile, which are fixed as a whole, together into the pile hole, and leaving a second preset length above the concrete square pile, it is placed above the pile hole. The through hole of the concrete square pile is pre-set at the pile body position from the top of the pile down to the second pre-set length; When the reinforced concrete square pile and the column pile, which are fixed as one piece, are lowered into the pile hole to leave a second preset length above the concrete square pile, the concrete square pile is supported above the pile hole by the steel bar.

5. The construction method for deep foundation pit support columns according to claim 1, characterized in that, During the process of welding and fixing the metal plates embedded around the perimeter of the concrete square pile to the steel reinforcement cage of the column pile when the concrete square pile is inserted to the first preset position, metal components are used to fix the concrete square pile to the steel reinforcement cage. The metal component is a reinforcing bar; one end of the reinforcing bar is welded to the metal plate, and the other end of the reinforcing bar is welded to the reinforcing cage of the column pile.

6. The construction method for deep foundation pit support columns according to claim 1, characterized in that, The pile driver includes a pile driver body made of H-beams or I-beams and a horizontal steel plate fixed at the bottom of the pile driver body; the area of ​​the horizontal steel plate is equal to the area of ​​the top cross section of the concrete square pile and the same shape; the horizontal steel plate is provided with bolt through holes corresponding to the positions of the connecting bolts, and the bolt through holes are adapted to the connecting bolts; a hoisting hole is provided at the upper part of the pile driver body.

7. The construction method for deep foundation pit support columns according to claim 1, characterized in that, During the process of pouring concrete between the steel reinforcement cage of the column pile and the concrete square pile, which is lowered to the second preset position, Concrete is poured between the steel reinforcement cage of the column pile and the concrete square pile using a conduit with a diameter of 150~200mm.

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