Fabricated open caisson multi-stage sinking construction method

Abstract

The invention relates to a multi-stage sinking construction method for an assembled open caisson, which comprises the following steps: on the basis of conventional open caisson construction, mounting a steel base with active stretching and retracting and active steering functions at the bottom of the open caisson, and mounting a supporting mechanism with an active stretching and retracting function between open caisson pipe joints; the construction method is characterized by comprising the following steps that S1, soil body excavation is conducted, specifically, the soil body at the bottom of the open caisson is excavated to the set depth; the open caisson has three different sinking control modes on the basis that the steel base with the active stretching and retracting function and the active steering function is installed at the bottom of the open caisson and the supporting mechanism with the active stretching and retracting function is installed between the open caisson pipe joints; different control modes can be selected to adapt to different sinking resistances to guarantee normal sinking construction of the open caisson, multi-stage sinking can be achieved through cooperation of the different control modes, and the sinking posture of the open caisson is guaranteed synchronously. The technical problems that according to a traditional assembly type open caisson construction method, sinking is difficult due to large sinking resistance, and the structural posture control capacity is poor are solved.

Description

Technical Field

[0001] The present invention relates to the technical field of caisson construction, in particular to a multi-stage sinking construction method for an assembled caisson. Background Art

[0002] Caisson technology is widely used in deep-buried projects such as bridge foundations and underground structures. Precise control of its sinking posture is a core challenge to ensure structural safety and construction efficiency.

[0003] In traditional construction, caissons are easily affected by factors such as uneven geology, excavation disturbance, and external forces, resulting in tilting, offset, and even "stuck" and other posture control problems; existing correction methods such as unilateral over-excavation, weight pressing, water injection, etc. often have lags, large disturbances and limited effects, especially in caissons with large depths and large cross-sections.

[0004] To this end, realizing active steering correction of the caisson base, actively offsetting the unbalanced torque caused by the caisson posture deviation, improving the adaptability and posture stability of the caisson when passing through complex formations, and reducing the disturbance to the surrounding soil are important research directions for realizing intelligent and high-precision construction of prefabricated caissons. They have significant theoretical value and broad engineering application prospects. Summary of the Invention

[0005] The purpose of the present invention is to overcome the defects of the prior art and provide a multi-stage sinking construction method for an assembled caisson, so as to solve the problems in the prior art of the traditional assembled caisson construction method in which the sinking resistance is large, resulting in difficulty in sinking and poor control ability of the structural posture.

[0006] To achieve the above-mentioned object, the present invention provides a multi-stage sinking construction method for an assembled caisson. Based on conventional assembled caisson construction, a steel base with both active telescopic and active steering functions is installed at the bottom of the caisson, and a support mechanism with active telescopic functions is installed between the caisson pipe sections. The construction method comprises the following steps:

[0007] S1. Soil excavation: excavate the soil at the bottom of the caisson to the set depth;

[0008] S2, Segment splicing: Assemble new pipe segments at the top of the caisson;

[0009] S3. Sinking control: Use the downward pressure mechanism to apply downward pressure to the caisson, while monitoring the offset of the center plane at the lower end of the steel base and the downward pressure applied by the downward pressure mechanism. Based on the monitoring results, select one of the following control modes:

[0010] Control mode 1: When the downward pressure is less than the set threshold, the downward pressure mechanism is continuously controlled to press downward and the steel base is adjusted to maintain the caisson posture until the downward pressure stroke of the downward pressure mechanism on the caisson is equal to the width of one ring of segments;

[0011] Control mode 2: When the downward pressure exceeds the set threshold and the caisson cannot sink, the steel base is adjusted to maintain the caisson's posture while controlling its lower end to extend actively until the lower end of the steel base extends a distance equal to the width of one ring of segments. The downward pressure mechanism is then controlled to press the caisson downward and the steel base is simultaneously controlled to retract until the downward pressure stroke of the downward pressure mechanism on the caisson is equal to the width of one ring of segments.

[0012] Control mode three: When the pressing mechanism still fails to sink in control mode two, the support mechanism is controlled to extend and the steel base is controlled to retract synchronously until the support mechanism extends to a distance equal to the width of one ring of segments. The pressing mechanism is then controlled to press down the caisson and the support mechanism is controlled to retract synchronously until the pressing stroke of the pressing mechanism on the caisson is equal to the width of one ring of segments.

[0013] S4. Circular construction: Repeat the above steps S2-S3 until the caisson sinks to the designed elevation.

[0014] By adopting this technical solution, a steel base with active telescopic and active steering functions is installed at the bottom of the caisson, and a support mechanism with active telescopic function is installed between the caisson pipe sections. As a result, the caisson has three different sinking control modes. By selecting different control modes, it can adapt to different sinking resistances to ensure the normal sinking construction of the caisson. It can also achieve multi-stage sinking through the coordination of different control modes and simultaneously ensure the sinking posture of the caisson, thereby solving the technical problems of traditional caisson construction methods that are difficult to sink due to large sinking resistance and poor structural posture control ability.

[0015] Furthermore, the steel base with both active telescopic and active steering functions includes a steel pipe section, a steel blade foot and a steering jack; wherein,

[0016] The steel pipe section is connected to the lower end of the caisson;

[0017] The steel blade foot is located below the steel pipe section;

[0018] The steering jacks are evenly distributed along the circumference between the steel pipe section and the steel blade foot, and any of the steering jacks can be controlled independently;

[0019] The steering jack base is fixedly connected to the lower bottom surface of the steel pipe section, and the steering jack piston rod end is hinged to the top surface of the steel blade foot.

[0020] By adopting this technical solution, when multiple steering jacks located between the steel pipe section and the steel blade foot are independently controlled, the angle of the steel blade foot relative to the steel pipe section can be changed, thereby coordinating the continued sinking of the caisson to achieve the steering effect and realize the corresponding steering capability, and the steering control only needs to overcome the pressure of the soil outside the steel blade foot, and the required control pressure is small, safe and fast; when multiple steering jacks located between the steel pipe section and the steel blade foot are controlled together, the steering jacks can push the steel blade foot to move vertically downward to achieve the telescopic function, and the caisson can be sunk first by moving the steel blade foot downward, and the sinking of the caisson does not need to overcome the soil resistance of the bottom end face, thereby reducing the downward force required for the sinking of the caisson and solving the sinking difficulty caused by excessive sinking resistance.

[0021] Furthermore, the steel base with both active telescopic and active steering functions also includes an inner ring plate, an outer ring plate and a double-layer sealing ring; wherein,

[0022] The inner ring plate and the outer ring plate are respectively connected to the inner and outer sides of the top surface of the steel blade foot, and the upper ends of the inner ring plate and the outer ring plate extend to the outer periphery of the top end of the steel pipe section;

[0023] The double-layer sealing ring is respectively installed on a side of the inner ring plate and the outer ring plate away from the steel blade foot and close to the steel pipe section.

[0024] By adopting this technical solution, the setting of the double-layer sealing ring can respectively achieve sealing between the inner ring plate and the steel pipe section and between the outer ring plate and the steel pipe section, thereby preventing external water and soil from entering the interior of the steel base.

[0025] Furthermore, the steel base with both active telescopic and active steering functions also includes an oil chamber and a grease injection pump; wherein,

[0026] The oil chamber is formed by double-layer sealing rings between the inner ring plate and the inner wall of the steel pipe section and between the outer ring plate and the outer wall of the steel pipe section;

[0027] The grease injection pump is connected to the oil chamber through a grease injection pipe.

[0028] By adopting this technical solution, the oil cavity is formed and the grease injection pump is set. During the caisson operation, the pressure inside the oil cavity can be adjusted by the grease injection pump, thereby improving the effect of resisting external water and soil intrusion and achieving the purpose of protecting the internal structure.

[0029] Furthermore, the supporting mechanism with active telescopic function includes a lower sleeve, an upper sleeve and a relay jack; wherein,

[0030] The lower sleeve has an inverted U-shaped vertical cross-section and is fixedly connected to the lower end of the upper pipe segment;

[0031] The upper sleeve has a vertical cross-section of a regular U shape and is fixedly connected to the upper end of the lower pipe section, and the upper sleeve and the lower sleeve are sleeved with each other;

[0032] The relay jacks are evenly distributed along the circumferential direction between the lower sleeve and the upper sleeve, and the relay jacks evenly distributed along the circumferential direction are controlled together;

[0033] The relay jack base is fixedly connected to the inner top surface of the lower sleeve, and the piston rod end of the relay jack is fixedly connected to the inner bottom surface of the upper sleeve.

[0034] By adopting this technical solution, the socket connection between the lower and upper sleeves enables the two to move relative to each other. With the addition of the relay jack, the lower and upper sleeves can be extended and retracted by controlling the relay jack, so as to achieve the purpose of applying pressure to the middle of the caisson.

[0035] Furthermore, the pressing mechanism includes a rotatable reaction frame and a pressing jack; wherein,

[0036] The rotatable reaction frame includes a column fixed to the ground and a horizontal frame horizontally rotatably connected to the top of the column;

[0037] The base of the downward pressure jack is connected to the bottom surface of the horizontal frame and can be moved to the top of the caisson with the rotation of the horizontal frame.

[0038] By adopting this technical solution, the setting of the rotatable reaction frame can change the position of the downward pressure jack used for applying pressure, so as to adapt to the needs of caisson sinking construction and new pipe section assembly. Specifically, when the downward pressure jack moves to the top of the caisson under the action of the rotatable reaction frame, it can apply pressure to the caisson to carry out caisson sinking operations. When the downward pressure jack moves outside the caisson under the action of the rotatable reaction frame, the new pipe section can be assembled normally.

[0039] Furthermore, the pressing mechanisms are evenly distributed along the periphery of the top of the caisson, and the evenly distributed pressing mechanisms are controlled together.

[0040] By adopting this technical solution, the evenly distributed and jointly controlled downward pressure mechanisms can provide stable downward pressure during caisson construction, which is beneficial to improving the posture control effect of the caisson.

[0041] Compared with the prior art, the present invention has the following beneficial effects:

[0042] Based on the installation of a steel base with active telescopic and active steering functions at the bottom of the caisson and the installation of a support mechanism with active telescopic function between the caisson pipe sections, the caisson has three different sinking control modes. It can adapt to different sinking resistances by selecting different control modes to ensure the normal sinking construction of the caisson. It can also achieve multi-stage sinking through the coordination of different control modes and simultaneously ensure the sinking posture of the caisson, thereby solving the technical problems of traditional prefabricated caisson construction methods that lead to sinking difficulties due to large sinking resistance and poor structural posture control ability. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 Schematic diagram of the process of the multi-stage sinking construction method of the assembled caisson in the present invention;

[0044] Figure 2 It is a schematic diagram of the overall construction elevation of the multi-stage sinking construction method of the assembled caisson in the present invention;

[0045] Figure 3 Schematic diagram of soil excavation for the multi-stage sinking construction method of the assembled caisson in the present invention;

[0046] Figure 4 Schematic diagram of segment splicing in the multi-stage sinking construction method of the assembled caisson in the present invention;

[0047] Figure 5 This is a schematic diagram of the control mode 1 of the multi-stage sinking construction method of the assembled caisson in the present invention before sinking construction;

[0048] Figure 6 This is a schematic diagram of the control mode of the multi-stage sinking construction method of the assembled caisson in the present invention after sinking construction;

[0049] Figure 7 Schematic diagram of control mode 2 of the multi-stage sinking construction method for assembled caisson in the present invention before sinking construction;

[0050] Figure 8 Schematic diagram of the control mode 2 of the multi-stage sinking construction method of the assembled caisson in the present invention after sinking construction;

[0051] Figure 9 Schematic diagram of control mode 3 of the multi-stage sinking construction method for assembled caisson in the present invention before sinking construction;

[0052] Figure 10 This is a schematic diagram of the control mode three after sinking construction of the multi-stage sinking construction method of the prefabricated caisson in the present invention.

[0053] Explanation of the accompanying symbols: 1. Steel pipe section; 2. Steel blade foot; 3. Steering jack; 4. Double-layer sealing ring; 5. Inner ring plate; 6. Outer ring plate; 7. Oil chamber; 8. Grease pump; 9. Relay jack; 10. Rotatable reaction frame; 11. Down-pressure jack. DETAILED DESCRIPTION

[0054] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0055] Please see the attached Figure 2 The present invention provides a multi-stage sinking construction method for an assembled caisson. Based on conventional assembled caisson construction, a steel base with both active telescopic and active steering functions is installed at the bottom of the caisson, a supporting mechanism with active telescopic functions is installed between the caisson pipe sections, and the existing pressing mechanism is improved. Specifically:

[0056] The steel base, which has both active telescopic and active steering functions, includes a steel pipe section 1, a steel blade foot 2, and a steering jack 3. The steel pipe section 1 is connected to the lower end of the caisson; the steel blade foot 2 is located below the steel pipe section 1; the steering jacks 3 are evenly distributed along the circumference between the steel pipe section 1 and the steel blade foot 2, and any steering jack 3 can be independently controlled; the base of the steering jack 3 is fixedly connected to the lower surface of the steel pipe section 1, and the piston rod end of the steering jack 3 is hinged to the top surface of the steel blade foot 2.

[0057] The arrangement, connection and coordination of the above structure, when the multiple steering jacks 3 located between the steel pipe section 1 and the steel blade foot 2 are independently controlled, can change the angle of the steel blade foot 2 relative to the steel pipe section 1, thereby coordinating the continued sinking of the caisson to achieve the steering effect and realize the corresponding steering capability, and the steering control only needs to overcome the soil pressure outside the steel blade foot 2, and the pressure needs to be controlled to be small, safe and fast; when the multiple steering jacks 3 located between the steel pipe section 1 and the steel blade foot 2 are controlled together, the steering jacks 3 can push the steel blade foot 2 to move vertically downward to achieve the telescopic function, and the caisson can be sunk first by the downward movement of the steel blade foot 2, and the sinking of the caisson does not need to overcome the soil resistance of the bottom end face, thereby reducing the downward force required for the sinking of the caisson and solving the sinking difficulty caused by excessive sinking resistance.

[0058] Furthermore, the steel base with both active telescopic and active steering functions also includes an inner ring plate 5, an outer ring plate 6 and a double-layer sealing ring 4; wherein the inner ring plate 5 and the outer ring plate 6 are respectively connected to the inner and outer sides of the top surface of the steel blade foot 2, and the upper ends of the inner ring plate 5 and the outer ring plate 6 extend to the outer periphery of the top of the steel pipe section 1; the double-layer sealing ring 4 is respectively installed on the side of the inner ring plate 5 and the outer ring plate 6 away from the steel blade foot 2 and close to the steel pipe section 1;

[0059] With the arrangement, connection and coordination of the above structures, the double-layer sealing ring 4 can respectively realize the sealing between the inner ring plate 5 and the steel pipe section 1 and between the outer ring plate 6 and the steel pipe section 1, thereby preventing external water and soil from entering the interior of the steel base.

[0060] Furthermore, the steel base with both active telescopic and active steering functions also includes an oil chamber 7 and a grease injection pump 8; wherein the oil chamber 7 is formed between the inner ring plate 5 and the inner wall of the steel pipe section 1 and between the outer ring plate 6 and the outer wall of the steel pipe section 1 through a double-layer sealing ring 4; the grease injection pump 8 is connected to the oil chamber 7 through a grease injection pipe;

[0061] The arrangement, connection and coordination of the above structures can adjust the pressure inside the oil chamber 7 through the grease injection pump 8 during the caisson operation, thereby improving the effect of resisting external water and soil intrusion and achieving the purpose of protecting the internal structure.

[0062] The support mechanism with active telescopic function includes a lower sleeve, an upper sleeve and a relay jack 9; wherein, the lower sleeve has an inverted U-shaped vertical section and is fixedly connected to the lower end of the upper pipe section; the upper sleeve has a positive U-shaped vertical section and is fixedly connected to the upper end of the lower pipe section, and the upper and lower sleeves are mutually connected; the relay jacks 9 are evenly distributed along the circumferential direction between the lower and upper sleeves, and the relay jacks 9 evenly distributed along the circumferential direction are jointly controlled; the base of the relay jack 9 is fixedly connected to the inner top surface of the lower sleeve, and the piston rod end of the relay jack 9 is fixedly connected to the inner bottom surface of the upper sleeve;

[0063] The arrangement, connection and coordination of the above structures enable the lower sleeve and the upper sleeve to be capable of moving relative to each other. With the addition of the relay jack 9, the lower sleeve and the upper sleeve can be extended and retracted relative to each other by controlling the relay jack 9, so as to achieve the purpose of applying pressure to the middle of the caisson.

[0064] Furthermore, the support mechanism can be selectively set according to the sinking construction depth and soil conditions during the actual construction process, and is not required to be set between any adjacent pipe sections, thereby reducing the cost of use.

[0065] The downward pressure mechanism includes a rotatable reaction frame 10 and a downward pressure jack 11; wherein the rotatable reaction frame 10 includes a column fixed to the ground and a horizontal frame horizontally connected to the top of the column; the downward pressure jack 11 base is connected to the bottom surface of the horizontal frame and can move to the top of the caisson with the rotation of the horizontal frame;

[0066] With the arrangement, connection and coordination of the above structures, the rotatable reaction frame 10 can change the position of the downward pressure jack 11 used for applying pressure to adapt to the needs of caisson sinking construction and new pipe section assembly. Specifically, when the downward pressure jack 11 moves to the top of the caisson under the action of the rotatable reaction frame 10, it can apply pressure on the caisson to perform caisson sinking operations. When the downward pressure jack 11 moves outside the caisson under the action of the rotatable reaction frame 10, the new pipe section can be assembled normally.

[0067] Furthermore, the downward pressure mechanism is evenly distributed along the periphery of the top of the caisson, and the evenly distributed downward pressure mechanism is jointly controlled; the evenly distributed and jointly controlled downward pressure mechanism can provide stable downward force for caisson construction, which is beneficial to improving the posture control effect of the caisson.

[0068] Please see the attached Figure 1 , the construction method includes the following steps:

[0069] S1. Soil excavation: Please refer to the attached Figure 3 , use the grab bucket to dig out the soil at the bottom of the caisson until the soil level is near the bottom of the steel blade foot;

[0070] S2. Segment splicing: Please refer to the attached Figure 4 , assemble a new ring of pipe sections on the top of the caisson;

[0071] S3. Sinking control: Please refer to the attached Figure 5 , adjust the downward pressure jack 11 to the position just above the top of the new pipe ring through the rotatable reaction frame 10, start the downward pressure jack 11 to apply downward pressure to the caisson from the top of the new pipe ring, and simultaneously monitor the offset of the center plane of the lower end of the steel blade foot 2 and the downward pressure applied by the downward pressure jack 11. Based on the monitoring results, select one of the following control modes:

[0072] Control mode 1: Please refer to the attached Figure 6 When the downward force applied by the pressing jack 11 is less than the set threshold, the relay jack 9 is locked and the pressing jack 11 is continuously controlled to press downward. At the same time, the steering jack 3 is fine-tuned to maintain the bottom center of the steel blade foot 2 at the design center to maintain the caisson posture until the downward stroke of the pressing jack 11 on the caisson is equal to the width of a new ring of segments.

[0073] Control mode 2: Please refer to the attached Figure 7-8, when the downward force applied by the pressing jack 11 exceeds the set threshold and the caisson cannot sink, the pressing jack 11 and the relay jack 9 are locked, and the steering jack 3 is fine-tuned to keep the bottom center of the steel blade foot 2 at the design center to maintain the posture of the steel blade foot 2, and then the multiple steering jacks 3 are synchronously controlled to extend, so that the steel blade foot 2 sinks compared to the steel pipe section 1 until the extension distance of the steel blade foot 2 is equal to the width of a new ring of segments, and then the pressing jack 11 is controlled to press down the caisson and the multiple steering jacks 3 are synchronously controlled to retract until the pressing stroke of the pressing jack 11 on the caisson is equal to the width of a new ring of segments;

[0074] In this control mode, it should be noted that there is a situation where the downward stroke of the pressing jack 11 is less than the width of a new ring of segments. In this case, the distance that the steel blade foot 2 sinks should be the width of the new ring of segments minus the downward stroke of the pressing jack 11. Correspondingly, after the sinking control of the steel blade foot 2 is completed, the downward stroke of the pressing jack 11 is the same as the distance the steel blade foot 2 has sunk.

[0075] Control mode 3: Please refer to the attached Figure 9-10 , when the sinking control of the steel blade foot 2 is completed in the second control mode and the caisson cannot be controlled to sink by the pressure jack 11, the pressure jack 11 should be locked first, and then the relay jack 9 should be controlled to extend and the steering jack 3 should be controlled to retract. At this time, the caisson part below the relay jack 9 should be sunk first until the extension distance of the relay jack 9 is equal to the width of the new ring of segments. Then the pressure jack 11 should be controlled to press down the caisson part above the relay jack 9 and the relay jack 9 should be controlled to retract until the downward stroke of the pressure jack 11 on the caisson is equal to the width of the new ring of segments.

[0076] In this control mode, it should be noted that, similar to control mode 2, there is a situation where the downward pressure jack 11 presses down to a certain stroke and does not meet the width of a new ring of segments. In this case, after the sinking of the steel blade foot 2 is controlled, the extended length of the relay jack 9 should be the same as the sinking distance of the steel blade foot 2. Correspondingly, after the caisson part below it controlled by the relay jack 9 sinks, the stroke of the downward pressure jack 11 continuing to press down should be the same as the extended length when the relay jack 9 controls the sinking of the caisson part below it.

[0077] S4, cyclic construction: move the downward pressure jack 11 to outside the top of the caisson through the rotatable reaction frame 10, and repeat steps S2-S3 until the caisson sinks to the designed elevation.

[0078] In the above construction method, the offset of the center plane of the lower end of the steel blade foot 2 and the downward pressure applied by the downward pressure jack 11 are monitored using corresponding standard monitoring equipment, such as using a position sensor and a pressure sensor for separate monitoring.

[0079] The present invention has been described in detail above with reference to the embodiments of the accompanying drawings. A person skilled in the art can make various modifications to the present invention based on the above description. Therefore, certain details in the embodiments should not be construed as limiting the present invention. The scope of protection of the present invention shall be determined by the scope defined in the appended claims.

Claims

1. A multi-stage sinking construction method for an assembled caisson, based on conventional assembled caisson construction, wherein a steel base with both active telescopic and active steering functions is installed at the bottom of the caisson, and a support mechanism with active telescopic function is installed between the caisson pipe sections; characterized in that: The construction method comprises the following steps: S1. Soil excavation: excavate the soil at the bottom of the caisson to the set depth; S2, Segment splicing: Assemble new pipe segments at the top of the caisson; S3. Sinking control: Use the downward pressure mechanism to apply downward pressure to the caisson, while monitoring the offset of the center plane at the lower end of the steel base and the downward pressure applied by the downward pressure mechanism. Based on the monitoring results, select one of the following control modes: Control mode 1: When the downward pressure is less than the set threshold, the downward pressure mechanism is continuously controlled to press downward and the steel base is adjusted to maintain the caisson posture until the downward pressure stroke of the downward pressure mechanism on the caisson is equal to the width of one ring of segments; Control mode 2: When the downward pressure exceeds the set threshold and the caisson cannot sink, the steel base is adjusted to maintain the caisson's posture while controlling its lower end to extend actively until the lower end of the steel base extends a distance equal to the width of one ring of segments. The downward pressure mechanism is then controlled to press the caisson downward and the steel base is simultaneously controlled to retract until the downward pressure stroke of the downward pressure mechanism on the caisson is equal to the width of one ring of segments. Control mode three: When the pressing mechanism still fails to sink in control mode two, the support mechanism is controlled to extend and the steel base is controlled to retract synchronously until the support mechanism extends to a distance equal to the width of one ring of segments. The pressing mechanism is then controlled to press down the caisson and the support mechanism is controlled to retract synchronously until the pressing stroke of the pressing mechanism on the caisson is equal to the width of one ring of segments. S4. Circular construction: Repeat the above steps S2-S3 until the caisson sinks to the designed elevation.

2. The multi-stage sinking construction method of the assembled caisson according to claim 1 is characterized in that: The steel base with both active telescopic and active steering functions includes a steel pipe section, a steel blade foot and a steering jack; wherein, The steel pipe section is connected to the lower end of the caisson; The steel blade foot is located below the steel pipe section; The steering jacks are evenly distributed along the circumference between the steel pipe section and the steel blade foot, and any of the steering jacks can be controlled independently; The steering jack base is fixedly connected to the lower bottom surface of the steel pipe section, and the steering jack piston rod end is hinged to the top surface of the steel blade foot.

3. The multi-stage sinking construction method of the assembled caisson according to claim 2 is characterized in that: The steel base with both active telescopic and active steering functions also includes an inner ring plate, an outer ring plate and a double-layer sealing ring; wherein, The inner ring plate and the outer ring plate are respectively connected to the inner and outer sides of the top surface of the steel blade foot, and the upper ends of the inner ring plate and the outer ring plate extend to the outer periphery of the top end of the steel pipe section; The double-layer sealing ring is respectively installed on a side of the inner ring plate and the outer ring plate away from the steel blade foot and close to the steel pipe section.

4. The multi-stage sinking construction method of an assembled caisson according to claim 3 is characterized in that: The steel base with both active telescopic and active steering functions also includes an oil chamber and a grease injection pump; wherein, The oil chamber is formed by double-layer sealing rings between the inner ring plate and the inner wall of the steel pipe section and between the outer ring plate and the outer wall of the steel pipe section; The grease injection pump is connected to the oil chamber through a grease injection pipe.

5. The multi-stage sinking construction method of an assembled caisson according to claim 1 is characterized in that: The supporting mechanism with active telescopic function includes a lower sleeve, an upper sleeve and a relay jack; wherein, The lower sleeve has an inverted U-shaped vertical cross-section and is fixedly connected to the lower end of the upper pipe segment; The upper sleeve has a vertical cross-section of a regular U shape and is fixedly connected to the upper end of the lower pipe section, and the upper sleeve and the lower sleeve are sleeved with each other; The relay jacks are evenly distributed along the circumferential direction between the lower sleeve and the upper sleeve, and the relay jacks evenly distributed along the circumferential direction are controlled together; The relay jack base is fixedly connected to the inner top surface of the lower sleeve, and the piston rod end of the relay jack is fixedly connected to the inner bottom surface of the upper sleeve.

6. The multi-stage sinking construction method of an assembled caisson according to claim 1 is characterized in that: The pressing mechanism includes a rotatable reaction frame and a pressing jack; wherein, The rotatable reaction frame includes a column fixed to the ground and a horizontal frame horizontally rotatably connected to the top of the column; The base of the downward pressure jack is connected to the bottom surface of the horizontal frame and can be moved to the top of the caisson with the rotation of the horizontal frame.

7. The multi-stage sinking construction method of an assembled caisson according to claim 6 is characterized in that: The pressing mechanisms are evenly distributed along the periphery of the top of the caisson, and the evenly distributed pressing mechanisms are controlled together.

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