Construction method for sinking a caisson foundation rock section

Abstract

The application discloses a construction method for sinking a caisson rock section, which comprises the following specific steps: S1, making a caisson, which is composed of a well wall and a blade foot; S2, sinking the caisson into the rock section, selecting and surrounding a plurality of jacks under the blade foot of the caisson, and arranging support pads on the top of the jacks for supporting the blade foot; S3, arranging prefabricated pads at the bottom of the jacks to lift the height of the blade foot; S4, dividing the operation range of each jack, shrinking the plunger of the jack one by one, cutting the cross section of the rock section in the operation range and newly arranging prefabricated pads, and cyclically operating until the final sinking depth; S5, removing the prefabricated pads under the jacks one by one until all the prefabricated pads are removed; and S6, replacing the jacks by replacement pads and pouring and sealing the bottom of the caisson. In the sinking construction of the caisson in the rock section, the blasting technology is no longer needed, the sinking operation of the caisson in the rock section can be realized, and the delay of the construction period is avoided.

Description

Technical Field

[0001] This invention relates to the field of caisson engineering technology, and in particular to a construction method for sinking the bedrock section of a caisson. Background Technology

[0002] A caisson is a cylindrical structure formed by excavating soil into the well and allowing it to sink to the designed elevation under its own weight, overcoming the frictional resistance of the well walls. The bottom is then sealed with concrete, and the well opening is filled, making it the foundation for bridge piers or other structures. It is commonly used in the construction of foundation pits for large bridge piers, sewage pumping stations, large equipment foundations, civil defense shelters, shield tunnel assembly shafts, and hydraulic foundations for underground tracks and railway stations.

[0003] Caissons are suitable for soil layers and can sink relatively quickly under their own weight. However, they are difficult to sink in hard rock layers, such as bedrock. In the past, blasting technology was generally used to achieve sinking. However, blasting operations and explosives are on the key regulatory list, and it is difficult to apply for operations in certain areas at certain times. If blasting is not used, it is difficult to continue construction with existing construction techniques after the caisson is in the bedrock, which will easily delay the construction period. Therefore, it is necessary to design a construction method that can replace the existing blasting to achieve the sinking of caissons in bedrock and avoid delays in the construction period. Summary of the Invention

[0004] The purpose of this invention is to provide a construction method for sinking the bedrock section of a caisson.

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

[0006] A construction method for sinking the bedrock section of a caisson includes the following steps:

[0007] S1. Constructing a caisson, which consists of a caisson wall and a cutting edge;

[0008] S2. When the caisson enters the bedrock section, multiple jacks are selected and installed around the cutting edge of the caisson, and support pads are installed on the top of the jacks to support the cutting edge.

[0009] S3. Set prefabricated pads at the bottom of the jack to raise the height of the cutting foot;

[0010] S4. Divide the working range of each jack, retract the plunger of each jack one by one, cut the bedrock section within the working range and make new precast pads, and repeat the operation until the final sinking depth.

[0011] S5. Remove the precast pads under the jack one by one until they are all removed;

[0012] S6. Replace the jacks with replacement pads to seal the bottom of the caisson.

[0013] Furthermore, the number of jacks in step S2 is related to the total weight of the caisson, and the specific formula is as follows:

[0014]

[0015] Where n is the number of jacks, G k Where is the total weight of the caisson, k = 2 is the safety factor, and N is the lifting weight of the jack, which is ≤300KN.

[0016] Furthermore, step S3 specifically includes the following steps:

[0017] S31. The plunger is lifted together by all jacks to support the caisson against the support pad block;

[0018] S32. Select a jack and retract its plunger to unload and release it. Add a precast pad block to the bottom of the jack and lift the plunger to restore the load support.

[0019] S33. Perform S32 operation on each jack in a cycle to raise the height of the space under the cutting edge until it reaches the drilling height of the worker.

[0020] Furthermore, step S4 specifically includes the following steps:

[0021] S41. Divide the working area of ​​a single jack according to the average subordinate area;

[0022] S42. According to the working range, select a jack to retract its plunger to unload and release the cutting edge of the working range;

[0023] S43. Preset a certain cutting depth, drill vertical and horizontal holes in the bedrock section below the jack, connect them, pass through the wire rope cutting, first perform vertical section cutting, then perform horizontal section cutting, perform section cutting on each side of the area, and clean the bedrock in the work area after the cutting is completed.

[0024] S44. Add a pre-set pad block to support the jack in the bedrock section below the jack, and restore the load support of the jack lifting plunger.

[0025] S45. Repeat the above actions for each jack to cut new bedrock sections, and continue the operation until the final sinking depth is reached.

[0026] Furthermore, step S5 specifically includes the following steps:

[0027] S51. Based on the working range, select a jack to retract its plunger to unload and release the cutting edge of the working range;

[0028] S52. Remove the precast pad block under the jack, raise the jack plunger, and restore the load support;

[0029] S53. Repeat the above actions for each jack until all pads under the jacks are removed.

[0030] Furthermore, step S6 specifically includes the following steps:

[0031] S61. A replacement pad for replacing the jack is placed on one side of each jack.

[0032] S62. Lower the plunger of each jack until the replacement pad replaces the cutting edge of the jack supporting the caisson;

[0033] S63. Remove all jacks and support blocks, and pour and seal the bottom of the caisson.

[0034] By adopting the above technical solution, the present invention has the following advantages compared with the prior art:

[0035] This invention eliminates the need for blasting techniques during the sinking of caissons in bedrock sections. Instead, under strict supervision of blasting and explosives in specific locations and at specific times, jacks and prefabricated blocks are used to support the caisson and allow for cutting operations. The bedrock section within the work area is then repeatedly cut until the final sinking depth is reached. This replaces existing blasting methods and enables caisson sinking in bedrock sections, avoiding delays in the construction schedule. Attached Figure Description

[0036] Figure 1 This is a flowchart of the method of the present invention;

[0037] Figure 2 This is a schematic diagram of the caisson and jack of the present invention;

[0038] Figure 3 This is a side view of the caisson of the present invention;

[0039] Figure 4 This is a schematic diagram of the jack of the present invention positioned between the cutting edge of the caisson and the bedrock section;

[0040] Figure 5 This is a top view of the cross-section cut of the present invention;

[0041] Figure 6 This is a side view of the cross-section cut of the present invention. Detailed Implementation

[0042] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0043] It should be noted that in this invention, the terms "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. are all based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element of this invention must have a specific orientation, and therefore should not be construed as a limitation of this invention.

[0044] Example

[0045] Cooperate Figures 1 to 6 As shown, this invention discloses a construction method for sinking the bedrock section of a caisson 1, comprising the following steps:

[0046] S1. Construct caisson 1, which consists of a well wall and a cutting edge.

[0047] S2. When the caisson 1 enters the bedrock section, multiple jacks 2 are selected and arranged around the cutting edge of the caisson 1, and support pads 3 are set on the top of the jacks 2 to support the cutting edge.

[0048] S3. Set a prefabricated pad 4 at the bottom of the jack 2 to raise the height of the cutting edge.

[0049] S4. Divide the working range of each jack 2, retract the plunger of each jack 2 one by one, cut the bedrock section within the working range and install new precast pad blocks 4, and repeat the operation until the final sinking depth.

[0050] S5. Remove the precast pads 4 under the jack 2 one by one until they are all removed.

[0051] S6. Replace jack 2 with replacement pads and pour the bottom seal for caisson 1.

[0052] Step S2 includes the following specific steps:

[0053] S21. Select and arrange jack 2. Select jack 2 with a lifting capacity of 500KN, and its lifting capacity during operation shall not exceed 300KN.

[0054] The placement of jack 2 is not limited in this embodiment. It can be that an installation hole is dug in the caisson 1 according to the layout requirements, the hole is placed below the cutting foot, and jack 2 is placed in the installation hole to lift and support the caisson 1.

[0055] The number of jacks 2 in step S2 is related to the total weight of caisson 1, and the specific formula is as follows:

[0056]

[0057] Where n is the number of jacks, G k Where is the total weight of the caisson, k = 2 is the safety factor, and N is the lifting capacity of the jack, preferably within the range of ≤300KN.

[0058] S22. Design review and construction requirements for the cutting edge.

[0059] Based on the arrangement of jack 2, the circular caisson cutting edge is regarded as a continuous horizontal circular ring beam. Under the action of uniformly distributed load q0 (caisson self-weight), its shear force, bending moment and torque can be found in the table below, and the cutting edge section and reinforcement are verified.

[0060] The table below shows the internal force coefficients for calculating a circular ring beam.

[0061]

[0062] Where R is the radius of caisson 1, and the calculation method for the self-weight of caisson 1 is existing technology, which will not be elaborated in this embodiment.

[0063] As the supporting surface of jack 2, the bottom width of the cutting foot tread should be no less than 300mm.

[0064] Step S3 specifically includes the following steps:

[0065] S31. The plunger is lifted by each jack 2 together to support the caisson 1 by contacting the support pad block 3.

[0066] S32. Select jack 2 and retract its plunger to unload and release it. Add prefabricated pad block 4 to the bottom of jack 2 and lift the plunger to restore the load support.

[0067] S33. Perform S32 operation on each jack 2 in a cycle to raise the height of the space under the cutting edge until it reaches the drilling height of the worker.

[0068] The drilling height for workers is not limited in this example; it is based on existing technology and will be adjusted according to different caissons.

[0069] Step S4 specifically includes the following steps:

[0070] S41. Based on the average subordinate area, divide the working area of ​​single jack 2.

[0071] Each jack 2 has the same working range and is positioned at the center of that working range.

[0072] S42. According to the working range, select jack 2 and retract its plunger to unload and release the cutting edge of the working range.

[0073] S43. Preset a certain cutting depth, drill vertical and horizontal holes in the bedrock section below jack 2, connect them, pass through the wire rope, first perform vertical section cutting, then perform horizontal section cutting, perform section cutting on each side of the area, and clean the bedrock in the work area after the cutting is completed.

[0074] The cutting section is cut using a wire cutter 5. The middle area of ​​the caisson 1 is hollowed out as the cutting working surface, so that the wire cutter 5 can cut the bedrock of the bedrock section through the wire cutter wire rope. The wire cutter 5 is existing technology and is not limited in this embodiment.

[0075] The section cutting requires cutting four sections. The specific steps include: first, cutting vertical sections one and two, as follows: preset a certain cutting depth, drill vertical and horizontal holes, connect them, pass the wire rope through, and cut. After completing vertical sections one and two, turn the wire rope cutting device 5 disc to the horizontal position and cut vertical section three. After cutting to the specified depth, perform horizontal cutting to cut horizontal section four, thus ending the cutting operation in this area.

[0076] S44. Add a pre-set pad block to support jack 2 in the bedrock section below jack 2, and jack 2 lifts the plunger to restore the load support.

[0077] S45. Repeat the above actions for each jack 2 cycles to cut new bedrock sections, and continue the cycle until the final sinking depth is reached.

[0078] Step S5 specifically includes the following steps:

[0079] S51. According to the working range, select jack 2 and retract its plunger to unload and release the cutting edge of the working range.

[0080] S52. Remove the precast pad 4 below the jack 2, lift the plunger of the jack 2, and restore the load support.

[0081] S53. Repeat the above actions for each jack 2 until all pads under jack 2 are removed.

[0082] In this embodiment, the precast pads 4 of the jacks 2 can be removed one by one. If the plunger can meet the height of multiple precast pads 4, multiple precast pads 4 can be removed at once. By the contraction of the plunger of each jack 2, the position of the caisson 1 can be adjusted. The final sinking depth of the caisson 1 can be adjusted according to the construction requirements. Alternatively, the caisson 1 can be measured and adjusted in position and balance while sinking. Then, steps S3-S5 can be repeated until the final sinking depth is reached.

[0083] Step S6 specifically includes the following steps:

[0084] S61. A replacement pad for replacing the jack 2 is placed on one side of each jack 2.

[0085] S62. Lower the plungers of each jack 2 until the replacement pad replaces the cutting edge of the caisson 1 supported by the jack 2.

[0086] S63. Remove each jack 2 and support pad 3, and pour and seal the bottom of the caisson 1.

[0087] In this embodiment, the caisson 1 is sunk in the bedrock section without the need for blasting. Instead, at specific times and in specific areas, under strict supervision of blasting and explosives, jacks 2 and prefabricated pads 4 are used to support the caisson 1 and leave space for cutting operations. The bedrock section within the working area is cut repeatedly until the final sinking depth is reached. This construction method, which replaces blasting, enables the caisson 1 to sink in the bedrock section, avoiding delays in the construction period.

[0088] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A construction method for sinking a caisson in bedrock section, characterized in that, Includes the following steps: S1. Constructing a caisson, which consists of a caisson wall and a cutting edge; S2. When the caisson enters the bedrock section, multiple jacks are selected and installed around the cutting edge of the caisson, and support pads are installed on the top of the jacks to support the cutting edge. S3. Set prefabricated pads at the bottom of the jack to raise the height of the cutting foot; S4. Divide the working range of each jack, retract the plunger of each jack one by one, cut the bedrock section within the working range and add new precast pads, and repeat the operation until the final sinking depth. S5. Remove the precast pads under the jack one by one until they are all removed; S6. Replace the jacks with replacement pads to seal the bottom of the caisson.

2. The construction method for sinking the bedrock section of a caisson as described in claim 1, characterized in that: The number of jacks in step S2 is related to the total weight of the caisson, and the specific formula is as follows: Where n is the number of jacks, G k Where is the total weight of the caisson, k = 2 is the safety factor, and N is the lifting weight of the jack, which is ≤300KN.

3. The construction method for sinking the bedrock section of a caisson as described in claim 1, characterized in that, Step S3 specifically includes the following steps: S31. The plunger is lifted together by all jacks to support the caisson against the support pad block; S32. Select a jack and retract its plunger to unload and release it. Add a precast pad block to the bottom of the jack and lift the plunger to restore the load support. S33. Perform S32 operation on each jack in a cycle to raise the height of the space under the cutting edge until it reaches the drilling height of the worker.

4. The construction method for sinking the bedrock section of a caisson as described in claim 3, characterized in that, Step S4 specifically includes the following steps: S41. Divide the working area of ​​a single jack according to the average subordinate area; S42. According to the working range, select a jack to retract its plunger to unload and release the cutting edge of the working range; S43. Preset a certain cutting depth, drill vertical and horizontal holes in the bedrock section below the jack, connect them, pass through the wire rope cutting, first perform vertical section cutting, then perform horizontal section cutting, perform section cutting on each side of the area, and clean the bedrock in the work area after the cutting is completed. S44. Add a pre-set pad block to support the jack in the bedrock section below the jack, and restore the load support of the jack lifting plunger. S45. Repeat the above actions for each jack to cut new bedrock sections, and continue the operation until the final sinking depth is reached.

5. The construction method for sinking the bedrock section of a caisson as described in claim 4, characterized in that, Step S5 specifically includes the following steps: S51. Based on the working range, select a jack to retract its plunger to unload and release the cutting edge of the working range; S52. Remove the precast pad block under the jack, raise the jack plunger, and restore the load support; S53. Repeat the above actions for each jack until all pads under the jacks are removed.

6. The construction method for sinking the bedrock section of a caisson as described in claim 5, characterized in that, Step S6 specifically includes the following steps: S61. A replacement pad for replacing the jack is placed on one side of each jack. S62. Lower the plunger of each jack until the replacement pad replaces the cutting edge of the jack supporting the caisson; S63. Remove all jacks and support blocks, and pour and seal the bottom of the caisson.

Images