Bored pile deep foundation pit supporting structure and construction method

Abstract

The application relates to the technical field of deep foundation pit support, and particularly discloses a bored pile deep foundation pit support structure and a construction method, the bored pile deep foundation pit support structure comprises an inner support, the inner support comprises a mounting cylinder, multistage telescopic structures and pressing plates, the two groups of multistage telescopic structures can at least partially extend to the two ends of the mounting cylinder and extend in the length direction of the mounting cylinder, and the mounting cylinder is provided with a driving mechanism, a locking mechanism and an unlocking mechanism. The driving mechanism can adjust the length of the multistage telescopic structures, so that the pressing plates at the two ends abut against the inner wall of the deep foundation pit; when the pressing plates firmly abut against the inner wall of the deep foundation pit, the locking mechanism limits the adjusting function of the multistage telescopic structures, so that the length of the multistage telescopic structures remains fixed; at this time, the multistage telescopic structures can stably abut the pressing plates against the inner wall of the deep foundation pit, so as to realize stable support of the inner wall of the deep foundation pit.

Description

A deep foundation pit support structure for bored cast-in-place piles and its construction method Technical Field

[0001] This application relates to the field of deep foundation pit support technology, and in particular to a deep foundation pit support structure and construction method using bored cast-in-place piles. Background Technology

[0002] Foundation pits are temporary works that provide a space for foundation construction to be carried out in the locations specified in the design. To ensure the safety of underground structure construction and the surrounding environment of the foundation pit, it is usually necessary to support the side walls of the foundation pit and the surrounding environment.

[0003] There are various forms of deep foundation pit support, including pile support, soil nailing wall support, sheet pile support, SMW method piles, PC method piles, diaphragm wall support, and reinforced concrete internal bracing support.

[0004] In the pile support method, it is usually composed of cast-in-place piles, supports and anti-seepage curtains. Multiple cast-in-place piles are arranged in sequence along the side wall of the deep foundation pit. The anti-seepage curtain is usually set in two rows, which are respectively surrounded on both sides of the cast-in-place piles, thereby effectively preventing water from outside the cast-in-place piles from seeping into the deep foundation pit and affecting normal construction.

[0005] In pile foundation support, various construction methods are employed. Internal support typically utilizes cast-in-place reinforced concrete or steel structures. In steel structure support, segmented steel pipes are transported to the construction site and then connected and fixed using flanges to achieve the required support length. However, this method requires manual connection of each pipe, and the stability of the connection point must be tested before support work can proceed. After the deep foundation pit support is completed, the internal support needs to be dismantled, requiring a second dismantling of the pipe connection points, resulting in low overall construction efficiency. Therefore, improvements are needed. Summary of the Invention

[0006] To improve the efficiency of deep foundation pit support operations, this application provides a drilled pile deep foundation pit support structure and construction method.

[0007] This application provides a deep foundation pit support structure for bored cast-in-place piles, employing the following technical solution:

[0008] A deep foundation pit support structure for bored piles includes an internal support. The internal support includes an installation cylinder, two sets of multi-stage telescopic structures symmetrically arranged within the installation cylinder, and pressure plates disposed at the telescopic ends of the two sets of multi-stage telescopic structures. At least a portion of the two sets of multi-stage telescopic structures can extend from both ends of the installation cylinder and extend along the length direction of the installation cylinder. The installation cylinder is respectively provided with a driving mechanism for driving the telescopic movement of the two sets of multi-stage telescopic structures, a locking mechanism for locking the two sets of multi-stage telescopic structures when they extend to the support length, and an unlocking mechanism for unlocking the multi-stage telescopic structures after the locking mechanism has locked them.

[0009] By adopting the above technical solution, the drive mechanism can adjust the length of the multi-stage telescopic structure, allowing the pressure plates at both ends to abut against the inner wall of the deep foundation pit. When the pressure plates are firmly pressed against the inner wall of the deep foundation pit, the locking mechanism restricts the adjustment function of the multi-stage telescopic structure, keeping its length fixed. At this point, the multi-stage telescopic structure can stably press the pressure plates against the inner wall of the deep foundation pit, thus achieving stable support for the inner wall. After the support of the deep foundation pit is completed, the unlocking mechanism can be used to quickly readjust the length of the multi-stage telescopic structure, making it easy to remove the multi-stage telescopic structure from the side wall of the deep foundation pit. Compared with traditional connection and installation methods, the entire support and dismantling process is more convenient and faster, improving overall construction efficiency.

[0010] Optionally, the multi-stage telescopic structure includes a first sleeve and a second sleeve that are slidably fitted together, wherein the first sleeve is slidably installed inside the mounting cylinder and the second sleeve is slidably installed inside the first sleeve;

[0011] The driving mechanism includes a dual-head drive motor installed inside the mounting cylinder along the length of the mounting cylinder, a drive screw coaxially fixedly installed on the output end of the dual-head drive motor, a first rack and a second rack respectively installed on the inner wall of the mounting cylinder and the outer wall of the second sleeve along the length of the mounting cylinder, and a drive gear that passes through and is rotatably installed on the side wall of the first sleeve.

[0012] The rotation axes of the two output ends of the dual-head drive motor are collinear. Two drive screws are provided for the two sets of multi-stage telescopic structures. The threads of the two drive screws are opposite and are coaxially fixed to the two output ends of the dual-head drive motor. The drive screws are threadedly connected to the end of the first sleeve. The drive gears mesh with the first rack and the second rack respectively.

[0013] By adopting the above technical solution, when it is necessary to adjust the multi-stage telescopic structure to the required length, the dual-head drive motor is connected to an external power source, and the dual-head drive motor is turned on, causing the drive screw to rotate. The drive screw drives the first sleeve to move along the length direction of the mounting cylinder. At this time, the first sleeve moves away from the dual-head drive motor. When the first sleeve moves away from the dual-head drive motor, the first rack will drive the second rack to move through the drive gear. Since the second rack is fixed on the outer wall of the second sleeve, the drive gear will drive the second sleeve to move away from the dual-head drive motor through the second rack, thereby increasing the length of the entire multi-stage telescopic structure. This allows the pressure plate at the end of the multi-stage telescopic structure to abut against the side wall of the deep foundation pit, thus achieving support for the side wall of the deep foundation pit.

[0014] Optionally, a guide structure for guiding is provided between the first sleeve and the mounting sleeve and the second sleeve, respectively.

[0015] By adopting the above technical solution, the guide structure can guide the sliding between the mounting cylinder and the first sleeve, and between the first sleeve and the second sleeve, making the elongation and shortening of the multi-stage telescopic structure smoother.

[0016] Optionally, the guide structure includes guide posts fixedly installed on the outer walls of the first sleeve and the second sleeve along the length direction of the mounting cylinder, and the inner walls of the mounting cylinder and the first sleeve are provided with sliding grooves for sliding corresponding to the guide posts.

[0017] By adopting the above technical solution, the guide column is slidably installed in the corresponding groove, making the mutual sliding between the mounting cylinder, the first sleeve and the second sleeve smoother.

[0018] Optionally, the locking mechanism includes a first locking bar and a second locking bar. The first locking bar is disposed along the length direction of the first sleeve at the end of the first sleeve near the dual-head drive motor, and the second locking bar is disposed along the length direction of the mounting cylinder on the inner wall of the mounting cylinder.

[0019] The first locking bar and the second locking bar each have oblique sawtooth-shaped meshing teeth on their opposite sides. A mounting base is also provided on the inner wall of the mounting cylinder. The second locking bar is slidably mounted on the mounting base, and the second locking bar can move away from the first locking bar obliquely above or below it. The mounting base is also provided with a first reset member for driving the second locking bar to reset. The first reset member is used to make the meshing teeth on the second locking bar mesh with the meshing teeth on the first locking bar.

[0020] By adopting the above technical solution, during the movement of the first and second sleeves outward from the mounting cylinder, the first locking bar pushes the second locking bar, causing the meshing teeth on the second locking bar to separate from the meshing teeth on the first locking bar. At this time, the locking mechanism will not limit or lock the extension of the multi-stage telescopic structure. When the pressure plate abuts against the side wall of the deep foundation pit, the dual-head drive motor stops rotating. At this time, the first locking bar stops moving relative to the mounting cylinder. Under the pulling action of the first reset member, the second locking bar moves towards the first locking bar, causing the meshing teeth on the second locking bar to mesh with the meshing teeth on the first locking bar. At this time, the second locking bar locks and limits the retraction of the first locking bar, that is, the multi-stage telescopic structure cannot shorten, thus enabling the multi-stage telescopic structure to stably support the deep foundation pit.

[0021] Optionally, the unlocking mechanism includes a first power gear, a second power gear, a cam, a push block, and a push rod. The first power gear is coaxially fixed on the drive screw. The second power gear is rotatably installed in the mounting cylinder and meshes with the first power gear. The cam is coaxially fixed with the second power gear, and the cam is circumferentially spaced with multiple protrusions, with adjacent protrusions forming an inward concave shape.

[0022] The push block is fixedly installed on the side wall of the second locking bar, and the side of the push block near the cam is set as a wedge-shaped inclined surface. The push rod is slidably installed in the mounting cylinder, and the end near the push block is set as a wedge-shaped inclined surface corresponding to the push block. One end of the push rod is directly opposite the wedge-shaped inclined surface of the push block, and the other end is directly opposite the peripheral wall of the cam.

[0023] The unlocking mechanism further includes a second reset member, which is used to make the end of the push block near the cam elastically abut against the peripheral wall of the cam. When one end of the push rod abuts against the protrusion of the cam, the other end of the push rod pushes the push block to move away from the cam, so that the biting teeth of the second locking bar separate from the biting teeth of the first locking bar.

[0024] By adopting the above technical solution, after the support of the deep foundation pit is completed, the multi-stage telescopic structure needs to be disassembled from the side wall of the deep foundation pit. This can be achieved by simply rotating the dual-head drive motor in reverse, which in turn drives the drive screw to rotate in reverse. The drive screw then drives the first power gear to rotate, which in turn drives the second power gear to rotate. The second power gear then drives the cam to rotate. Since the tooth diameter of the second power gear is much smaller than that of the first power gear, the rotational speed of the second power gear is much greater than that of the first power gear. At this time, the faster-rotating second power gear will drive the cam to rotate rapidly. The end of the push rod will then abut against the spaced protrusions in sequence, causing the end of the push rod away from the cam to repeatedly push the push block to move away from the cam. When the cam rotates fast enough, the end of the push rod can be approximated as continuously abutting against multiple protrusions. At this time, the end of the push rod away from the cam continuously pushes the push block towards the direction of the cam, thus causing the meshing teeth on the second locking bar to separate from the meshing teeth on the first locking bar. At this time, the locking mechanism no longer limits and locks the extension and retraction of the multi-stage telescopic structure. Therefore, driven by the dual-head drive motor, the first sleeve and the second sleeve will retract towards the mounting cylinder, causing the pressure plate to separate from the side wall of the deep foundation pit. This achieves rapid disassembly of the multi-stage telescopic structure, greatly improving the efficiency of installation and disassembly, shortening the construction cycle, and making the construction operation convenient. Only a small amount of labor is needed to achieve rapid support of the deep foundation pit.

[0025] Optionally, the inner support is further provided with a pressure detection mechanism for monitoring the pressure on the multi-stage telescopic structure and the pressure plate, and an alarm mechanism for alerting the pressure signal detected by the pressure detection mechanism.

[0026] By adopting the above technical solution, the pressure detection mechanism can detect the pressure between the multi-stage expansion joint and the sidewall of the deep foundation pit. When the pressure meets the pressure resistance condition, it proves that the construction requirements have met the standards, and the alarm mechanism will not issue an alarm. When the pressure does not meet the pressure resistance condition, the construction requirements are not met, and the alarm mechanism will issue an alarm to warn the construction workers, thereby checking the construction process and improving the safety of deep foundation pit support.

[0027] Optionally, the pressure detection mechanism includes a first pressure sensor disposed on the side of the pressure plate away from the second sleeve, a second pressure sensor disposed between the first sleeve and the second sleeve for detecting the pressure between the first sleeve and the second sleeve, and a controller electrically connected to the first pressure sensor and the second pressure sensor respectively.

[0028] By adopting the above technical solution, the first pressure sensor can detect the pressure between the pressure plate and the side wall of the deep foundation pit, thereby detecting the support pressure of the pressure plate. The second pressure sensor can detect the expansion and contraction of the multi-stage expansion structure itself, which facilitates the monitoring of the structural strength of the multi-stage expansion structure, and makes it convenient to quickly detect whether the construction process meets the standards, thereby improving the safety of construction.

[0029] Optionally, the alarm mechanism includes an alarm and an indicator light disposed on the outer wall of the mounting cylinder, both of which are electrically connected to the controller.

[0030] By adopting the above technical solution, when both the first pressure sensor and the second pressure sensor are greater than the set value, the alarm will not sound and the indicator light will be constantly green. However, if the pressure value of either the first pressure sensor or the second pressure sensor fails to reach the set value, the alarm will sound and the indicator light will be constantly red.

[0031] This application also provides a construction method for deep foundation pit support using bored cast-in-place piles, comprising the following steps:

[0032] S1: Construct bored piles so that they are laid out along the perimeter of the deep foundation pit;

[0033] S2: Two rows of water-stop curtains are constructed on both sides of the bored pile;

[0034] S3: Weld and install steel support brackets on the pre-embedded steel plate of the bored pile cap beam;

[0035] S4: Hoist the installation cylinder so that the pressure plates at both ends of the installation cylinder are directly facing the steel support brackets on both sides of the deep foundation pit;

[0036] S5: Connect the dual-head drive motor to the external power supply, adjust the length of the multi-stage telescopic structure until the two pressure plates are tightly abutted against the steel support bracket, and complete the internal support of the bored pile.

[0037] In summary, this application includes at least one of the following beneficial technical effects:

[0038] 1. The drive mechanism can adjust the length of the multi-stage telescopic structure, allowing the pressure plates at both ends to abut against the inner wall of the deep foundation pit. When the pressure plates are firmly pressed against the inner wall of the deep foundation pit, the locking mechanism restricts the adjustment function of the multi-stage telescopic structure, keeping its length fixed. At this point, the multi-stage telescopic structure can stably press the pressure plates against the inner wall of the deep foundation pit, thus achieving stable support for the inner wall. After the support of the deep foundation pit is completed, the unlocking mechanism can be used to quickly readjust the length of the multi-stage telescopic structure, making it easy to remove the multi-stage telescopic structure from the side wall of the deep foundation pit. Compared with traditional connection and installation methods, the entire support and dismantling process is more convenient and faster, improving overall construction efficiency.

[0039] 2. The pressure testing mechanism can detect the pressure between the multi-stage expansion joint and the sidewall of the deep foundation pit. When the pressure meets the pressure resistance condition, it proves that the construction requirements have met the standards, and the alarm mechanism will not sound an alarm. When the pressure does not meet the pressure resistance condition, the construction requirements are not met, and the alarm mechanism will sound an alarm to warn the construction workers. This allows for the inspection of the construction process and improves the safety of the deep foundation pit support. Attached Figure Description

[0040] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0041] Figure 1 is a schematic diagram of the multi-stage telescopic structure in its installation state;

[0042] Figure 2 is a schematic diagram of the overall structure of the multi-stage telescopic structure;

[0043] Figure 3 is a schematic diagram of the internal structure of the multi-stage telescopic structure in Figure 2;

[0044] Figure 4 is an enlarged view of point A in Figure 3;

[0045] Figure 5 is a schematic diagram of the internal structure of the multi-stage telescopic structure in Figure 2 from another perspective;

[0046] Figure 6 is an enlarged view of point B in Figure 5.

[0047] Reference numerals in the attached drawings: 1. Cast-in-place pile body; 2. Mounting cylinder; 21. Divider plate; 22. Mounting base; 221. First reset component; 23. Support column; 3. Pressure plate; 4. Multi-stage telescopic structure; 41. First sleeve; 42. Second sleeve; 5. Drive mechanism; 51. Dual-head drive motor; 52. Drive screw; 53. First rack; 54. Second rack; 55. Drive gear; 6. Locking mechanism; 61. First locking bar; 611. Engaging teeth; 62. Second locking bar; 7. Unlocking mechanism; 71. First power gear; 72. Second power gear; 73. Cam; 731. Protrusion; 74. Push block; 75. Push rod; 8. Pressure detection mechanism; 81. First pressure sensor; 82. Second pressure sensor; 9. Alarm mechanism; 91. Alarm; 92. Indicator light. Detailed Implementation

[0048] The present application will be further described in detail below with reference to Figures 1-6.

[0049] This application discloses a deep foundation pit support structure for bored cast-in-place piles.

[0050] A deep foundation pit support structure for bored cast-in-place piles, as shown in Figures 1 and 2, includes a cast-in-place pile body 1, a water-stop curtain, a steel support bracket, and an internal support. The internal support includes an installation cylinder 2, two sets of multi-stage telescopic structures 4 symmetrically arranged inside the installation cylinder 2, and a pressure plate 3 arranged at the telescopic ends of the two sets of multi-stage telescopic structures 4.

[0051] Two sets of multi-stage telescopic structures 4 are symmetrically installed inside the installation cylinder 2, and at least part of the two sets of multi-stage telescopic structures 4 can extend from both ends of the installation cylinder 2 and extend along the length of the installation cylinder 2. During the extension process, the two sections of the pressure plate 3 can abut against the side wall of the deep foundation pit, thereby achieving the support of the side wall of the deep foundation pit.

[0052] The installation cylinder 2 is equipped with a drive mechanism 5 for driving the extension and retraction of two sets of multi-stage telescopic structures 4. The drive mechanism 5 can drive the two pressure plates 3 to move towards or away from the side wall of the deep foundation pit. The installation cylinder 2 is also equipped with a locking mechanism 6 for locking the extension and retraction of the two sets of multi-stage telescopic structures 4 and an unlocking mechanism 7 for unlocking the multi-stage telescopic structures 4 after locking.

[0053] The locking mechanism 6 can lock the extension and retraction of the multi-stage telescopic structure 4 in one direction, that is, the multi-stage telescopic structure 4 can only extend and cannot retract under the action of the driving mechanism 5. The unlocking mechanism 7 can unlock the locking limit of the locking mechanism 6, so that the driving mechanism 5 can drive the multi-stage telescopic structure 4 to retract.

[0054] Referring to Figure 2, the multi-stage telescopic structure 4 includes a first sleeve 41 and a second sleeve 42 that are slidably fitted together. The first sleeve 41 is slidably installed inside the mounting cylinder 2, and the second sleeve 42 is slidably installed inside the first sleeve 41.

[0055] Referring to Figures 2, 3 and 4, the drive mechanism 5 includes a dual-head drive motor 51, a drive screw 52, ​​a first rack 53, a second rack 54 and a drive gear 55. A partition plate 21 is fixedly installed inside the mounting cylinder 2. The partition plate 21 separates the two sets of multi-stage telescopic structures 4, and the two sets of multi-stage telescopic structures 4 are symmetrical about the partition plate 21.

[0056] A dual-head drive motor 51 is fixedly mounted on the partition plate 21. The two output ends of the dual-head drive motor 51 are located on both sides of the partition plate 21, and the two output ends are collinear. The rotation axes of the two output ends are parallel to the length direction of the mounting cylinder 2. Two drive screws 52 are provided. The two drive screws 52 are coaxially welded and fixed to the two output ends of the dual-head drive motor 51. The drive screws 52 are threadedly connected to the ends of the corresponding first sleeves 41, and the threads on the two drive screws 52 have opposite directions of rotation.

[0057] Two sets of first racks 53 and second racks 54 are provided respectively. The two sets of first racks 53 are fixedly installed on the two inner side walls of the mounting cylinder 2 along the length direction of the mounting cylinder 2, and the two sets of second racks 54 are fixedly installed on the outer side wall of the second sleeve 42 along the length direction of the second sleeve 42. Two drive gears 55 are provided accordingly. The two drive gears 55 are rotatably installed on the two side walls of the first sleeve 41, and extend through the side walls of the first sleeve 41 into the inner cavity and the outer side of the first sleeve 41, respectively. The drive gears 55 mesh with the corresponding first racks 53 and second racks 54.

[0058] When the dual-head drive motor 51 is working, it will drive the drive screw 52 to rotate, causing the first sleeve 41 to move away from the dual-head drive motor 51 along the length of the mounting cylinder 2. At this time, the first rack 53 will drive the second rack 54 to move through the drive gear 55, causing the second rack 54 to drive the second sleeve 42 to move away from the dual-head drive motor 51, thereby increasing the length of the entire multi-stage telescopic structure 4, thereby causing the pressure plates 3 at the ends of the two second sleeves 42 to abut against the side wall of the deep foundation pit.

[0059] To make the sliding between the mounting cylinder 2, the first sleeve 41 and the second sleeve 42 smoother, a guide structure is provided between the first sleeve 41 and the mounting cylinder 2 and the second sleeve 42 respectively. The guide structure includes a guide post fixedly installed on the outer wall of the first sleeve 41 and the outer wall of the second sleeve 42 along the length direction of the mounting cylinder 2. The inner wall of the mounting cylinder 2 and the inner wall of the first sleeve 41 are provided with a sliding groove for the corresponding guide post to slide.

[0060] When both pressure plates 3 are pressed against the corresponding deep foundation pit sidewalls, the locking mechanism 6 is required to lock the extension and retraction of the multi-stage telescopic structure 4. The locking mechanism 6 includes a first locking bar 61 and a second locking bar 62. Referring to Figures 3, 5 and 6, the first locking bar 61 is located at the end of the first sleeve 41 near the double-head drive motor 51 along the length direction of the first sleeve 41, and the second locking bar 62 is located on the inner wall of the mounting cylinder 2 along the length direction of the mounting cylinder 2.

[0061] The first locking bar 61 and the second locking bar 62 are provided with oblique sawtooth-shaped meshing teeth 611 on their opposite sides. A mounting base 22 is also fixedly installed on the inner wall of the mounting cylinder 2. The second locking bar 62 is slidably installed on the mounting base 22, and the second locking bar 62 can move away from the first locking bar 61 at an oblique upper or oblique lower angle. In this embodiment, the second locking bar 62 can slide at an oblique upper left angle to the first locking bar 61.

[0062] Referring to Figure 6, the mounting base 22 is also provided with a first reset member 221 for driving the second locking bar 62 to reset. The first reset member 221 is a spring. One end of the first reset member 221 is fixedly connected to the mounting base 22, and the other end is fixedly connected to the second locking bar 62. When the first locking bar 61 does not move, the first reset member 221 can make the biting teeth 611 on the second locking bar 62 bite each other, so that the second locking bar 62 completes the limiting of the first locking bar 61. At this time, regardless of whether the dual-head drive motor 51 drives the first sleeve 41 to retract, the first sleeve 41 cannot retract into the mounting cylinder 2, thus ensuring the stable contact between the pressure plate 3 and the side wall of the deep foundation pit.

[0063] After the support of the deep foundation pit is completed, the locking mechanism 6 needs to be unlocked through the unlocking mechanism 7, so that the multi-stage telescopic structure 4 can be quickly disassembled from the side wall of the deep foundation pit. Referring to Figure 1, the unlocking mechanism 7 includes a first power gear 71, a second power gear 72, a cam 73, a push block 74, a push rod 75, and a second reset member. There are multiple sets of unlocking mechanisms 7. In this embodiment, there are four sets of unlocking mechanisms 7, and the four sets of locking mechanisms 6 are arranged at intervals inside the mounting cylinder 2.

[0064] Specifically, the first power gear 71 is coaxially fixed on the drive screw 52, ​​the second power gear 72 is rotatably installed in the mounting cylinder 2 and meshes with the first power gear 71, the cam 73 is coaxially fixed with the second power gear 72, and the cam 73 is provided with multiple protrusions 731 at circumferential intervals, and the adjacent protrusions 731 are surrounded by an inward concave shape.

[0065] The push block 74 is fixedly installed on the side wall of the second locking bar 62, and the side of the push block 74 near the cam 73 is set as a wedge-shaped slope. A support column 23 is fixedly installed on the partition plate 21. The push rod 75 is slidably installed on the support column 23, and the end near the push block 74 is set as a wedge-shaped slope corresponding to the push block 74. One end of the push rod 75 is directly opposite the wedge-shaped slope of the push block 74, and the other end is directly opposite the peripheral wall of the cam 73.

[0066] The second reset component also uses a spring. The second reset component is installed on the support column 23 and is used to make the end of the push block 74 near the cam 73 elastically abut against the peripheral wall of the cam 73. When one end of the push rod 75 abuts against the protrusion 731 of the cam 73, the other end of the push rod 75 pushes the push block 74 to move away from the cam 73, so that the biting teeth 611 of the second locking bar 62 are separated from the biting teeth 611 of the first locking bar 61. At this time, the locking mechanism 6 can be unlocked, so that the multi-stage telescopic structure 4 can be telescopic under the drive of the drive screw 52.

[0067] When one end of the push rod 75 abuts against the concave part of the cam 73, the other end of the push rod 75 no longer pushes the push block 74 to move. Under the action of the first reset member 221, the biting teeth 611 on the second locking bar 62 re-engage with the biting teeth 611 on the first locking bar 61, thereby locking and fixing the first locking bar 61.

[0068] Since the tooth diameter of the second power gear 72 is much smaller than that of the first power gear 71, the rotational speed of the second power gear 72 is much greater than that of the first power gear 71. At this time, the faster-rotating second power gear 72 will drive the cam 73 to rotate rapidly. At this time, the end of the push rod 75 will abut against the spaced protrusions 731 in sequence, causing the end of the push rod 75 away from the cam 73 to repeatedly push the push block 74 to move away from the cam 73.

[0069] When the rotation speed of the cam 73 is fast enough, the end of the push rod 75 can be approximated as being in constant contact with multiple protrusions 731. At this time, the end of the push rod 75 away from the cam 73 will continuously push the push block 74 to the direction where the cam 73 is located, thus causing the biting teeth 611 on the second locking bar 62 to separate from the biting teeth 611 on the first locking bar 61. At this time, the locking mechanism 6 no longer limits and locks the extension and retraction of the multi-stage telescopic structure 4.

[0070] Therefore, when the dual-head drive motor 51 is working, the multi-stage telescopic structure 4 can freely extend and retract to adjust the position of the pressure plate 3, thereby enabling the installation and disassembly of the multi-stage telescopic structure 4. When the dual-head drive motor 51 is not working, the multi-stage telescopic structure 4 cannot rotate freely, thus achieving the length limit locking of the multi-stage telescopic structure 4, so that the multi-stage telescopic structure 4 can firmly press the pressure plate 3 against the side wall of the deep foundation pit.

[0071] Furthermore, in order to detect the expansion and contraction of the multi-stage telescopic structure 4 itself, and to detect the pressure between the pressure plate 3 and the side wall of the deep foundation pit, as shown in Figure 2, the inner support is also provided with a pressure detection mechanism 8 for monitoring the pressure on the multi-stage telescopic structure 4 and the pressure plate 3, and an alarm mechanism 9 for alarming the pressure signal detected by the pressure detection mechanism 8.

[0072] Referring to Figures 2 and 3, the pressure detection mechanism 8 includes a first pressure sensor 81, a second pressure sensor 82, and a controller. The first pressure sensor 81 is disposed on the side of the pressure plate 3 away from the second sleeve 42, and the second pressure sensor 82 is disposed between the first sleeve 41 and the second sleeve 42, capable of detecting the pressure between the first sleeve 41 and the second sleeve 42. The controller is electrically connected to the first pressure sensor 81, the second pressure sensor 82, and the alarm mechanism. The alarm mechanism 9 includes an alarm 91 and an indicator light 92, both of which are disposed on the outer wall of the mounting cylinder 2 and are electrically connected to the controller.

[0073] The first pressure sensor 81 can detect the pressure between the pressure plate 3 and the side wall of the deep foundation pit, thereby detecting the support pressure of the pressure plate 3. The second pressure sensor 82 can detect the expansion and contraction of the multi-stage expansion structure 4 itself, which facilitates the monitoring of the structural strength of the multi-stage expansion structure 4, and makes it convenient to quickly detect whether the construction process meets the standards, thereby improving the safety of construction.

[0074] The implementation principle of a deep foundation pit support structure for bored piles in this application embodiment is as follows: When it is necessary to support the inner wall of the deep foundation pit, the external power supply is connected to the drive mechanism 5. The drive mechanism 5 can adjust the length of the multi-stage telescopic structure 4 so that the pressure plates 3 at both ends abut against the inner wall of the deep foundation pit. When the pressure plates 3 are firmly pressed against the inner wall of the deep foundation pit, the locking mechanism 6 restricts the adjustment function of the multi-stage telescopic structure 4, so that the length of the multi-stage telescopic structure 4 remains fixed. At this time, the multi-stage telescopic structure 4 can stably press the pressure plates 3 against the inner wall of the deep foundation pit, thereby achieving stable support for the inner wall of the deep foundation pit.

[0075] After the support of the deep foundation pit is completed, the length of the multi-stage telescopic structure 4 can be quickly readjusted using the unlocking mechanism 7, so that the multi-stage telescopic structure 4 can be easily removed from the side wall of the deep foundation pit. Compared with the traditional connection and installation methods, the entire support and dismantling process is more convenient and faster, improving the overall construction efficiency.

[0076] This application also discloses a construction method for deep foundation pit support using bored cast-in-place piles, comprising the following steps:

[0077] S1: Construct bored piles so that they are laid out along the perimeter of the deep foundation pit;

[0078] S2: Two rows of water-stop curtains are constructed on both sides of the bored pile;

[0079] S3: Weld and install steel support brackets on the pre-embedded steel plate of the bored pile cap beam;

[0080] S4: Hoist the installation cylinder 2 so that the pressure plates 3 at both ends of the installation cylinder 2 are directly facing the steel support brackets on both sides of the deep foundation pit;

[0081] S5: Connect the dual-head drive motor 51 to the external power supply, adjust the length of the multi-stage telescopic structure 4 until the two pressure plates 3 are tightly abutted against the steel support bracket, and complete the internal support of the bored pile.

[0082] Unless otherwise defined, the technical or scientific terms used in this application shall have the ordinary meaning understood by one of ordinary skill in the art to which this application pertains. The terms "first," "second," "third," and similar terms used in this application specification and claims do not indicate any order, quantity, or importance, but are merely used to distinguish different components. The terms "a" or "an," and similar terms do not indicate a quantity limitation, but rather indicate the presence of at least one. The terms "comprising," "including," and similar terms mean that the elements or objects preceding "comprising" encompass the elements or objects listed following "comprising" or "including," and their equivalents, but do not exclude other elements or objects. "Above," "below," "left," "right," etc., are used only to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0083] The above are all optional embodiments of this application and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A deep foundation pit support structure for bored cast-in-place piles, comprising internal bracing, characterized in that: The inner support includes a mounting cylinder (2), two sets of multi-stage telescopic structures (4) symmetrically arranged inside the mounting cylinder (2), and pressure plates (3) disposed at the telescopic ends of the two sets of multi-stage telescopic structures (4). At least part of the two sets of multi-stage telescopic structures (4) can extend out from both ends of the mounting cylinder (2) and extend along the length of the mounting cylinder (2). The mounting cylinder (2) is respectively provided with a driving mechanism (5) for driving the two sets of multi-stage telescopic structures (4) to telescopic, and a locking mechanism (6) for locking the two sets of multi-stage telescopic structures (4) when they telescopically reach the support length. And an unlocking mechanism (7) for unlocking the multi-stage telescopic structure (4) after the locking mechanism (6) is locked; the multi-stage telescopic structure (4) includes a first sleeve (41) and a second sleeve (42) that are slidably fitted together, the first sleeve (41) being slidably installed in the mounting cylinder (2), and the second sleeve (42) being slidably installed in the first sleeve (41); the driving mechanism (5) includes a dual-head drive motor (51) installed in the mounting cylinder (2) along the length direction of the mounting cylinder (2), and a coaxial fixed installation on the output end of the dual-head drive motor (51). The drive screw (52), the first rack (53) and the second rack (54) are respectively installed on the inner wall of the mounting cylinder (2) and the outer wall of the second sleeve (42) along the length direction of the mounting cylinder (2), and the drive gear (55) is installed through and rotatably on the side wall of the first sleeve (41); the rotation axes of the two output ends of the dual-head drive motor (51) are collinear, and two drive screws (52) are provided for the two sets of multi-stage telescopic structures (4). The thread directions of the two drive screws (52) are opposite and they are respectively coaxially fixed to the two output ends of the dual-head drive motor (51). At the end, the drive screw (52) is threadedly connected to the end of the first sleeve (41), and the drive gear (55) meshes with the first rack (53) and the second rack (54) respectively; the locking mechanism (6) includes a first locking bar (61) and a second locking bar (62), the first locking bar (61) is disposed along the length direction of the first sleeve (41) at the end of the first sleeve (41) near the side of the double-head drive motor (51), and the second locking bar (62) is disposed along the length direction of the mounting cylinder (2) on the inner wall of the mounting cylinder (2);The first locking bar (61) and the second locking bar (62) are provided with serrated teeth (611) on their opposite sides. The inner wall of the mounting cylinder (2) is also provided with a mounting seat (22). The second locking bar (62) is slidably mounted on the mounting seat (22), and the second locking bar (62) can move away from the first locking bar (61) diagonally above or diagonally below it. The mounting seat (22) is also provided with a first reset member (221) for driving the second locking bar (62) to reset. The locking mechanism (7) is used to engage the teeth (611) on the second locking bar (62) with the teeth (611) on the first locking bar (61). The unlocking mechanism (7) includes a first power gear (71), a second power gear (72), a cam (73), a push block (74), and a push rod (75). The first power gear (71) is coaxially fixed on the drive screw (52). The second power gear (72) is rotatably mounted in the mounting cylinder (2) and meshes with the first power gear (71). The cam (73) and the second power gear (72) are coaxially fixed. The shaft is fixed, and the cam (73) is provided with a plurality of protrusions (731) spaced circumferentially, with adjacent protrusions (731) forming an inward concave shape; the push block (74) is fixedly installed on the side wall of the second locking strip (62), and the side of the push block (74) near the cam (73) is provided with a wedge-shaped inclined surface; the push rod (75) is slidably installed in the mounting cylinder (2), and the end near the push block (74) is provided with a wedge-shaped inclined surface corresponding to the push block (74); one end of the push rod (75) is directly opposite the wedge-shaped inclined surface of the push block (74), and the other end is opposite to the... The peripheral wall of the cam (73) faces each other; the unlocking mechanism (7) further includes a second reset member, which is used to make the end of the push block (74) near the cam (73) elastically abut against the peripheral wall of the cam (73). When one end of the push rod (75) abuts against the protrusion (731) of the cam (73), the other end of the push rod (75) pushes the push block (74) to move away from the cam (73), so that the biting teeth (611) of the second locking bar (62) separate from the biting teeth (611) of the first locking bar (61).

2. The deep foundation pit support structure for bored cast-in-place piles according to claim 1, characterized in that: The first sleeve (41) is provided with a guide structure between itself and the mounting sleeve (2) and the second sleeve (42).

3. The deep foundation pit support structure for bored cast-in-place piles according to claim 2, characterized in that: The guide structure includes guide posts fixedly installed on the outer wall of the first sleeve (41) and the outer wall of the second sleeve (42) along the length direction of the mounting cylinder (2). The inner wall of the mounting cylinder (2) and the inner wall of the first sleeve (41) are provided with sliding grooves for sliding corresponding to the guide posts.

4. The deep foundation pit support structure for bored cast-in-place piles according to claim 1, characterized in that: The inner support is also provided with a pressure detection mechanism (8) for monitoring the pressure on the multi-stage telescopic structure (4) and the pressure plate (3), and an alarm mechanism (9) for alarming the pressure signal detected by the pressure detection mechanism (8).

5. A deep foundation pit support structure for bored cast-in-place piles according to claim 4, characterized in that: The pressure detection mechanism (8) includes a first pressure sensor (81) disposed on the side of the pressure plate (3) away from the second sleeve (42), a second pressure sensor (82) disposed between the first sleeve (41) and the second sleeve (42) for detecting the pressure between the first sleeve (41) and the second sleeve (42), and a controller electrically connected to the first pressure sensor (81) and the second pressure sensor (82) respectively.

6. The deep foundation pit support structure for bored cast-in-place piles according to claim 5, characterized in that: The alarm mechanism (9) includes an alarm (91) and an indicator light (92) disposed on the outer wall of the mounting cylinder (2), and both the alarm (91) and the indicator light (92) are electrically connected to the controller.

7. A construction method for deep foundation pit support using bored cast-in-place piles, characterized in that, The deep foundation pit support structure using any one of claims 1 to 6 is described. Includes the following steps: S1: Construct the bored piles so that they are laid out along the perimeter of the deep foundation pit; S2: Construct two rows of water-stop curtains on both sides of the bored piles; S3: Weld and install steel support brackets on the embedded steel plates of the bored pile cap beam; S4: Hoist the installation cylinder (2) so that the pressure plates (3) at both ends of the installation cylinder (2) are directly opposite the steel support brackets on both sides of the deep foundation pit; S5: Connect the double-head drive motor (51) to the external power supply and adjust the length of the multi-stage telescopic structure (4) until the two pressure plates (3) are tightly abutted against the steel support brackets to complete the internal support of the bored piles.

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