Auxiliary device for open caisson sinking and underwater bottom sealing and construction method

Abstract

The invention discloses an auxiliary device for open caisson sinking and underwater bottom sealing and a construction method. The device comprises a plurality of air curtain vertical pipes arranged inside or on the outer side of the well wall of the open caisson, each air curtain vertical pipe extends to the lower end of the well wall from the upper end of the well wall, the bottom ends of the air curtain vertical pipes are communicated with annular pipes, the annular pipes surround the periphery of the well wall, and the outer sides of the annular pipes are communicated with branch pipes abutting against soil on the outer side of the well wall; the air curtain vertical pipe, the annular pipe and the branch pipes are filled with high-pressure compressed air. A bailey truss which is transversely arranged is arranged at the position of a well opening in the upper end of the well wall, a plurality of steel wire ropes are hung at the bottom of the bailey truss, anchoring steel bars which are vertically arranged are hung at the bottom end of each steel wire rope, and the anchoring steel bars are woven and positioned into a whole through a flexible steel wire net which is transversely arranged. According to the method, solutions can be provided in a targeted mode according to scenes, and the problems that sinking of the open caisson is difficult, the well body inclines, and anchoring steel bars are difficult to manually arrange in underwater bottom sealing concrete are solved.

Description

Technical Field

[0001] The invention relates to the technical field of caisson construction, and in particular to an auxiliary device and a construction method for caisson sinking and underwater bottom sealing. Background Art

[0002] Caisson construction is a method of underground engineering construction that is different from traditional support excavation. The well wall is poured with reinforced concrete on the ground, and the well wall is used as a retaining structure. The well wall is sunk into the soil by digging in the well, and finally an underground structure is formed after the bottom is sealed. It is usually used in the construction of underground pump rooms or bridge foundations.

[0003] When the geological conditions are complex or the caisson size is large, the calculated predicted sinking force and soil friction of the caisson structure are often inaccurate. The existing technology can only be used for construction through slow sinking, real-time measurement, and timely correction during the actual construction process. However, this construction method has the following problems:

[0004] First, the construction efficiency is low. Once a stratum with large friction resistance that has not been explored in the early stage appears, it will be difficult to sink, which will have a great impact on the construction period;

[0005] Second, the well body tilts, threatening the safety of the well body structure;

[0006] When the groundwater level is high, it is usually necessary to manually dive underwater to seal the bottom of the caisson, and use the bottom sealing concrete as part of the anti-floating structure. However, there are the following problems with manual underwater construction:

[0007] First, when divers arrange the reserved anchor steel bars underwater, it is easy for the steel bar spacing to deviate greatly from the design requirements;

[0008] Second, underwater construction is dangerous and inefficient. Summary of the invention

[0009] In view of the shortcomings of the prior art, the present invention proposes an auxiliary device and construction method for caisson sinking and underwater bottom sealing, which can provide targeted solutions according to different scenarios based on actual engineering problems, and effectively solve problems in caisson construction such as sinking difficulty, well body inclination, and difficulty in manually setting anchor steel bars in underwater bottom sealing concrete, so as to achieve the purpose of improving caisson construction efficiency and improving the safety of caisson structure.

[0010] In order to achieve the above-mentioned purpose, the auxiliary device for sinking and underwater bottom sealing of a caisson designed by the present invention is particularly characterized in that: it comprises a plurality of air curtain risers arranged at intervals inside or outside the caisson wall, each of the air curtain risers extends from the upper end of the caisson wall to the lower end of the caisson wall, the bottom end of the air curtain riser is connected to an annular pipe, the annular pipe surrounds the caisson wall, and the outer side of the annular pipe is connected to a branch pipe abutting against the soil outside the caisson wall;

[0011] The air curtain riser, the ring pipe, and the branch pipe are filled with high-pressure compressed air, so that an annular air curtain is formed between the well wall and the outer soil during the sinking construction of the caisson, thereby accelerating the sinking of the caisson;

[0012] A transversely arranged Bailey frame is provided at the wellhead at the upper end of the well wall, and a plurality of steel wire ropes are suspended at the bottom of the Bailey frame. A vertically arranged anchor steel bar is suspended at the bottom end of each of the steel wire ropes. The plurality of anchor steel bars are woven and positioned as a whole by a transversely arranged flexible steel wire mesh. The lower end of the anchor steel bar is located inside the underwater bottom sealing concrete, and the upper end of the anchor steel bar is located inside the anchor bottom plate.

[0013] Furthermore, a sand filling groove is excavated on the ground along the outer periphery of the caisson wall, and the interior of the sand filling groove is filled with sandy friction reducing material for reducing the friction resistance of the caisson sinking.

[0014] Furthermore, the Bailey frame is provided with bagged soil for static pressure-assisted sinking or static pressure correction, and the bagged soil is of standard weight.

[0015] Furthermore, the ring tube is provided with partitions arranged at intervals, and the partitions are used to divide the ring tube into small sections.

[0016] Furthermore, the number, spacing and specifications of the anchoring steel bars should be determined based on the caisson size and anti-floating calculations.

[0017] Furthermore, the steel wire rope is connected to the anchor steel bar by binding or welding.

[0018] The present invention also provides a construction method for sinking a caisson and sealing the bottom underwater, which is applicable to the auxiliary device for sinking a caisson and sealing the bottom underwater, and is particularly characterized in that it comprises the following steps:

[0019] S1) During the sinking of the caisson, if it is found that the caisson is difficult to sink, then go to step S2); if it is found that the caisson is tilted, then go to step S3); if the caisson is sealed underwater, then go to step S4);

[0020] S2) digging sand filling grooves around the caisson on the ground and filling them with sandy friction-reducing materials to assist the sinking of the caisson; and / or introducing high-pressure compressed air into the air curtain riser to assist the sinking of the caisson and observe the sinking of the caisson;

[0021] If the caisson still sinks too slowly or cannot sink, a Bailey frame is installed on the edge of the caisson to form a loading platform and static pressure is used to assist the sinking until the uniform load applied to the Bailey frame is greater than the friction between the caisson wall and the soil, and the caisson resumes normal sinking;

[0022] If the sinking speed of the caisson returns to normal, there is no need to install Bailey frames on the edge of the caisson;

[0023] S3) If the sand filling, air curtain and static pressure assisted sinking construction in step S2) above are not carried out at this time, a Bailey frame is installed on the edge of the caisson to form a loading platform, and static pressure correction measures are taken to continuously load uneven loads on the Bailey frame to tilt the caisson in the opposite direction until the caisson recovers and continues to sink normally;

[0024] If the sand filling, air curtain and static pressure assisted sinking in step S2) have been carried out, the air curtain assisted sinking measure is stopped and static pressure correction measures are carried out to continuously unload the uneven load on the Bailey frame to make the caisson tilt in the opposite direction until the caisson posture is restored and continues to sink normally;

[0025] S4) Install Bailey frames on the edge of the caisson to form a working platform; determine the number and length of anchor bars according to the design, weave a flexible wire mesh, fix vertical anchor bars at each node on the horizontal mesh, set a wire rope on the top of each anchor bar, lift the wire mesh through the wire rope, and lower it to the designed height, fix the top of the wire rope to the Bailey frame, pour underwater bottom concrete, drain the water at the bottom of the well, and complete the underwater bottom construction of the caisson.

[0026] Furthermore, in S2), the static pressure-assisted sinking measure is specifically to use a crane to pile bagged soil on the Bailey frame in a uniform, symmetrical and layered manner, and continue to load the bagged soil until the applied load is greater than the frictional resistance between the caisson wall and the soil, and the caisson resumes normal sinking.

[0027] Furthermore, in S3), when the sand filling assisted sinking, air curtain assisted sinking, and static pressure assisted sinking construction are not carried out, the static pressure correction measures are specifically to use a crane to pile bagged soil on the Bailey frame, and pile it in the opposite direction of the tilt direction, and continue to load until the uneven load applied causes the caisson to tilt in the opposite direction, and adjust the amount of bagged soil according to the posture of the caisson until the posture of the caisson is restored and continues to sink normally;

[0028] When sand filling to assist sinking, air curtain to assist sinking, and static pressure to assist sinking have been carried out, the static pressure correction measures are specifically to use a crane to unload the bagged soil in the inclined direction, and continue unloading until the applied uneven load causes the caisson to tilt in the opposite direction, and adjust the amount of bagged soil according to the posture of the caisson until the posture of the caisson is restored and continues to sink normally.

[0029] Furthermore, in S4), when the top end of the steel wire rope is fixed to the Bailey frame, the fixing position of the steel wire rope and the Bailey frame is adjusted on the Bailey frame so that the wire mesh is unfolded according to the design requirements, ensuring that the spacing of the anchor steel bars meets the design requirements.

[0030] The advantages of the present invention are:

[0031] 1. The present invention designs the auxiliary device into an air curtain sinking aid device, a sand filling sinking aid structure, a static pressure sinking aid / correction device, and an underwater bottom sealing auxiliary device; wherein the air curtain sinking aid device, the sand filling sinking aid structure, and the static pressure sinking aid / correction device can be partially or fully implemented according to different geological conditions and sinking difficulties, and have extremely high flexibility; for caisson construction with good geological conditions and low descent difficulty, only sand filling can be used to assist sinking, which is extremely low in cost and can achieve good drag reduction effect; for caisson construction with good geological conditions but high sinking difficulty, air curtain sinking can be used; for caisson construction with complex geological conditions and high sinking difficulty, the above measures can be taken in combination; the static pressure sinking aid / correction device can adjust the pile load weight to correct the deviation in time while assisting sinking, so as to solve the problem of well body tilting during caisson construction, and can effectively improve construction efficiency;

[0032] 2. The underwater bottom sealing auxiliary device of the present invention utilizes the Bailey frame construction platform in the static pressure sinking assistance / correction device to hoist the flexible steel wire mesh pre-tied with anchor steel bars to the bottom of the caisson in an integral or piecewise hoisting installation manner, pour underwater bottom sealing concrete, and then drain the water at the bottom of the well to complete the underwater bottom sealing construction of the caisson, thereby greatly reducing the cost of underwater construction, improving construction safety, and avoiding the problems of large deviation of the steel bar spacing from the design requirements due to the underwater arrangement of reserved anchor steel bars by divers, as well as high risk of underwater construction, and can effectively improve the reliability of the bottom sealing anchoring structure;

[0033] The auxiliary device and construction method for caisson sinking and underwater bottom sealing of the present invention can provide targeted solutions according to different scenarios based on actual engineering problems, effectively solving problems such as sinking difficulty, well body inclination, and difficulty in manually setting anchor steel bars in underwater bottom sealing concrete during caisson construction, thereby achieving the purpose of improving caisson construction efficiency and improving the safety of caisson structures. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 It is a cross-sectional schematic diagram of the installation of underwater bottom concrete anchoring steel bars in the present invention;

[0035] Figure 2 It is a schematic plan view of the underwater bottom sealing concrete anchoring steel bars woven into a mesh in the present invention;

[0036] Figure 3 It is a schematic diagram of the structure of the air curtain sinking aid device, the sand filling sinking aid structure, and the static pressure sinking aid / deviation correction device in the present invention;

[0037] Figure 4 It is a schematic plan view of the arrangement of the air curtain sinking aid device in the well wall in the present invention;

[0038] Figure 5 It is a flow chart of the construction method of the present invention;

[0039] In the figure: shaft wall 1, Bailey frame 2, bagged soil 3, steel wire rope 4, anchor steel bar 5, steel wire mesh 6, sand filling trough 7, sandy friction reducing material 8, ground 9, air curtain riser 10, ring pipe 11, partition 12, branch pipe 13, underwater bottom sealing concrete 14;

[0040] The air curtain sinking aid device comprises: an air curtain riser 10, a ring pipe 11, a partition 12, and a branch pipe 13;

[0041] The sand filling and sedimentation aiding structure comprises: a sand filling tank 7, a sandy friction reducing material 8, and a ground surface 9;

[0042] The static pressure sinking assistance / deviation correction device includes: Bailey frame 2, bagged soil 3;

[0043] The underwater bottom sealing auxiliary device comprises: a Bailey frame 2, a steel wire rope 4, an anchoring steel bar 5, a steel wire mesh 6, and an underwater bottom sealing concrete 14. DETAILED DESCRIPTION

[0044] The present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0045] In the description of the present invention, it is necessary to understand that the terms "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the invention.

[0046] like Figures 1 to 4 As shown, an auxiliary device for sinking a caisson and sealing the bottom underwater of the caisson of the present invention comprises a plurality of air curtain risers 10 arranged at intervals inside or outside the caisson wall 1, each of the air curtain risers 10 extending from the upper end of the wall 1 to the lower end of the wall 1, the bottom end of the air curtain riser 10 is connected to an annular pipe 11, the annular pipe 11 surrounds the wall 1, and the outer side of the annular pipe 11 is connected to a branch pipe 13 abutting against the soil outside the wall 1.

[0047] Specifically, the air curtain riser 10 is a riser pre-buried at intervals inside the caisson wall 1 or fixed at intervals outside the caisson wall 1 .

[0048] The number and spacing of the branch pipes 13 are determined according to the design.

[0049] The air curtain riser 10, the annular pipe 11, and the branch pipe 13 are filled with high-pressure compressed air, so that an annular air curtain is formed between the well wall 1 and the outer soil during the sinking construction of the caisson, thereby accelerating the sinking of the caisson.

[0050] Preferably, the ring tube 11 is provided with partitions 12 arranged at intervals, and the partitions 12 are used to divide the ring tube 11 into small sections.

[0051] A transversely arranged Bailey frame 2 is provided at the wellhead at the upper end of the well wall 1, and a plurality of steel wire ropes 4 are hoisted at the bottom of the Bailey frame 2. A vertically arranged anchor steel bar 5 is suspended at the bottom end of each of the steel wire ropes 4. The plurality of anchor steel bars 5 are woven and positioned as a whole by a transversely arranged flexible steel wire mesh 6. The lower end of the anchor steel bar 5 is located inside the underwater bottom sealing concrete 14, and the upper end of the anchor steel bar 5 is located inside the anchor bottom plate.

[0052] The caisson wall 1 may be rectangular or circular; the Bailey frame 2 is an expandable connector of standard specifications, and the corresponding size is selected by calculation according to the span of the caisson.

[0053] The number, spacing and specifications of the anchoring steel bars 5 should be determined according to the caisson size and anti-floating calculation. The steel wire rope 4 and the anchoring steel bars 5 are connected by tying or welding.

[0054] Specifically, the length of the anchor steel bar 5 inserted into the underwater bottom concrete 14 and the length reserved for anchoring into the bottom plate should be determined according to the anchor length corresponding to its diameter; the wire mesh 6 should have a certain fixing effect to ensure that the designed spacing can be maintained during the process of lowering the anchor steel bar 5 to the designed elevation, and can be divided into several pieces according to the size of the caisson.

[0055] Preferably, bagged soil 3 for static pressure-assisted sinking or static pressure-corrected deviation is provided on the Bailey frame 2, and the bagged soil 3 is of standard weight. The strength and stability of the platform erected by the Bailey frame 2 can meet the requirements of heap loading.

[0056] A sand filling groove 7 is excavated on the ground 8 along the outer periphery of the caisson wall 1, and the sand filling groove 7 is filled with sandy friction reducing material 8 for reducing the friction resistance of the caisson sinking.

[0057] Specifically, the size of the sand filling groove 7 should be determined according to the size of the caisson, and the cross section of the sand filling groove 7 should be the same along the four sides of the well wall 1. The sandy friction reducing material 8 can significantly reduce the friction resistance encountered by the caisson when sinking compared to the original soil.

[0058] The auxiliary device of the present invention mainly includes four parts: an air curtain sinking aid device, a sand-filling sinking aid structure, a static pressure sinking aid / correction device, and an underwater bottom sealing auxiliary device. Specifically, the air curtain sinking aid device includes an air curtain riser 10, a ring pipe 11, a partition 12, and a branch pipe 13; the sand-filling sinking aid structure includes a sand-filling trough 7, sand-type friction-reducing material 8, and a ground surface 9; the static pressure sinking aid / correction device includes a Bailey frame 2 and bagged soil 3; the underwater bottom sealing auxiliary device includes a Bailey frame 2, a steel wire rope 4, an anchor steel bar 5, a steel wire mesh 6, and an underwater bottom sealing concrete 14.

[0059] Among them, the air curtain sinking aid device, sand filling sinking aid structure, and static pressure sinking aid / correction device can be partially or fully implemented according to the different geological conditions and sinking difficulty, which has extremely high flexibility; for caisson construction with good geological conditions and less difficulty in descending, only sand filling can be adopted, which is extremely low in cost and can achieve better drag reduction effect; for caisson construction with good geological conditions but greater difficulty in sinking, air curtain sinking can be adopted; for caisson construction with complex geological conditions and greater difficulty in sinking, the above measures can be adopted in combination; the static pressure sinking aid / correction device can adjust the pile load weight to make timely corrections while assisting sinking, thereby solving the problem of well body tilt during caisson construction, and can effectively improve construction efficiency.

[0060] The present invention also designs a construction method for caisson sinking and underwater bottom sealing, which is suitable for the auxiliary device of the above-mentioned caisson sinking and underwater bottom sealing. The process usage scenarios mainly include: scenario a - the caisson is difficult to sink, and it is necessary to take measures to assist sinking; scenario b - the caisson is tilted, and it is necessary to take corrective measures; scenario c - the caisson is underwater bottom sealed, and it is necessary to use underwater bottom sealing concrete to participate in anti-floating.

[0061] like Figure 5 As shown, the construction method includes the following steps:

[0062] S1) When the caisson is being sunk, if it is found that the caisson is difficult to sink, then go to step S2); if it is found that the caisson is tilted, then go to step S3); if the caisson is being sealed underwater, then go to step S4).

[0063] S2) When it belongs to the use scenario a - the caisson is difficult to sink and it is necessary to take measures to assist the sinking, the construction steps are as follows:

[0064] Excavate sand filling grooves 7 on the ground 9 along the periphery of the caisson, and fill with sandy friction reducing materials 8 to assist the sinking of the caisson; and / or introduce high-pressure compressed air into the air curtain riser 10 to assist the sinking of the caisson, and observe the sinking of the caisson;

[0065] If the sinking speed of the caisson is still too slow or it cannot sink, a Bailey frame 2 is installed on the edge of the caisson to form a loading platform, and static pressure is used to assist the sinking until the uniform load applied to the Bailey frame 2 is greater than the friction between the caisson wall 1 and the soil, and the caisson resumes normal sinking;

[0066] If the sinking speed of the caisson returns to normal, there is no need to install the Bailey frame 2 on the edge of the caisson.

[0067] Specifically, the static pressure-assisted sinking measure is to use a crane to pile the bagged soil 3 on the Bailey frame 2 in a uniform, symmetrical and layered manner, and continue to load the bagged soil 3 until the applied load is greater than the frictional resistance between the caisson wall 1 and the soil, and the caisson resumes normal sinking.

[0068] S3) When it belongs to the use scenario b - the caisson is tilted and corrective measures need to be taken, the construction steps are as follows:

[0069] If the sand filling assisted sinking, air curtain assisted sinking, and static pressure assisted sinking construction of the above step S2) are not performed at this time, a Bailey frame 2 is installed on the edge of the caisson to form a loading platform, and static pressure correction measures are taken to continuously load uneven loads on the Bailey frame 2 to tilt the caisson in the opposite direction until the caisson posture is restored and continues to sink normally;

[0070] If the sand filling to assist sinking, air curtain to assist sinking, and static pressure to assist sinking in the above step S2) have been carried out at this time, the air curtain to assist sinking measures shall be stopped and static pressure correction measures shall be carried out. The uneven load shall be continuously unloaded on the Bailey frame 2 to make the caisson tilt in the opposite direction until the caisson posture is restored and normal sinking continues.

[0071] Specifically, when the sand filling assisted sinking, air curtain assisted sinking, and static pressure assisted sinking construction are not carried out, the static pressure correction measures are specifically to use a crane to pile the bagged soil 3 on the Bailey frame 2, and pile it in the opposite direction of the tilt direction, and continue to load until the uneven load applied causes the caisson to tilt in the opposite direction, and adjust the amount of bagged soil according to the posture of the caisson until the posture of the caisson is restored and continues to sink normally;

[0072] When sand filling to assist sinking, air curtain to assist sinking, and static pressure to assist sinking have been carried out, the static pressure correction measures are specifically to use a crane to unload the bagged soil 3 in the inclined direction, and continue unloading until the applied uneven load causes the caisson to tilt in the opposite direction, and adjust the amount of bagged soil according to the posture of the caisson until the posture of the caisson is restored and continues to sink normally.

[0073] S4) When it belongs to the use scenario c - underwater bottom sealing of caisson, it is necessary to use bottom sealing concrete to participate in anti-floating, the construction steps are as follows:

[0074] Bailey frames 2 are installed on the edge of the caisson to form a working platform. The number and length of anchoring steel bars 5 are determined according to the design, and flexible steel meshes 6 are woven to fix vertical anchoring steel bars 5 at each node on the horizontal mesh. Steel wire ropes 4 are set on the top of each anchoring steel bar 5. The steel meshes 6 are lifted by the steel wire ropes 4 and lowered to the designed height. The tops of the steel wire ropes 4 are fixed to the Bailey frames 2, and underwater bottom sealing concrete 14 is poured. The water at the bottom of the well is drained to complete the underwater bottom sealing construction of the caisson.

[0075] The present invention sets the wire mesh 6 as a flexible wire mesh, the purpose of which is to facilitate the adjustment of the spacing of the anchor steel bars 5 by adjusting the spacing of the wire ropes 4, thereby avoiding the problem that the steel bar spacing deviates greatly from the design requirements due to the divers arranging the reserved anchor steel bars 5 underwater.

[0076] Specifically, when the top end of the steel wire rope 4 is fixed to the Bailey frame 2, the fixing position of the steel wire rope 4 and the Bailey frame 2 is adjusted on the Bailey frame 2, so that the steel mesh 6 is unfolded according to the design requirements, ensuring that the spacing of the anchor steel bars 5 meets the design requirements.

[0077] The auxiliary device and construction method for caisson sinking and underwater bottom sealing of the present invention can provide targeted solutions according to different scenarios based on actual engineering problems, effectively solving problems such as sinking difficulty, well body inclination, and difficulty in manually setting anchor steel bars in underwater bottom sealing concrete during caisson construction, thereby achieving the purpose of improving caisson construction efficiency and improving the safety of caisson structures.

[0078] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be equivalent replacement methods and are included in the protection scope of the present invention.

Claims

1. An auxiliary device for sinking a caisson and sealing the bottom underwater, characterized in that: The invention comprises a plurality of air curtain risers (10) arranged at intervals inside or outside a caisson wall (1), each of the air curtain risers (10) extending from the upper end of the caisson wall (1) to the lower end of the caisson wall (1), the bottom end of the air curtain riser (10) being connected to an annular pipe (11), the annular pipe (11) surrounding the caisson wall (1), the outer side of the annular pipe (11) being connected to a branch pipe (13) abutting against the soil outside the caisson wall (1); The air curtain riser (10), the annular pipe (11), and the branch pipe (13) are filled with high-pressure compressed air, so that an annular air curtain is formed between the well wall (1) and the outer soil during the sinking of the caisson, thereby accelerating the sinking of the caisson; A transversely arranged Bailey frame (2) is provided at the wellhead at the upper end of the well wall (1), and a plurality of steel wire ropes (4) are suspended at the bottom of the Bailey frame (2). A vertically arranged anchor steel bar (5) is suspended at the bottom end of each of the steel wire ropes (4). The plurality of anchor steel bars (5) are woven and positioned as a whole through a transversely arranged flexible steel wire mesh (6), and the lower end of the anchor steel bar (5) is located inside the underwater bottom sealing concrete (14), and the upper end of the anchor steel bar (5) is located inside the anchor bottom plate.

2. The auxiliary device for sinking and underwater bottom sealing of caisson according to claim 1 is characterized by: A sand filling groove (7) is excavated on the ground (9) along the outer periphery of the caisson wall (1), and the sand filling groove (7) is filled with sandy friction reducing material (8) for reducing the friction resistance of the caisson sinking.

3. The auxiliary device for sinking and underwater bottom sealing of caisson according to claim 2 is characterized by: The Bailey frame (2) is provided with bagged soil (3) for static pressure-assisted sinking or static pressure-corrected deviation, and the bagged soil (3) is of standard weight.

4. The auxiliary device for sinking and underwater bottom sealing of caisson according to claim 3 is characterized by: The ring tube (11) is provided with partitions (12) arranged at intervals, and the partitions (12) are used to divide the ring tube (11) into small sections.

5. The auxiliary device for sinking and underwater bottom sealing of caisson according to claim 1 is characterized by: The number, spacing and specifications of the anchoring steel bars (5) should be determined according to the caisson size and anti-floating calculation.

6. The auxiliary device for sinking and underwater bottom sealing of caisson according to claim 5 is characterized by: The steel wire rope (4) and the anchoring steel bar (5) are connected by binding or welding.

7. A construction method for sinking a caisson and sealing the bottom underwater, applicable to the auxiliary device for sinking a caisson and sealing the bottom underwater as claimed in any one of claims 1 to 6, characterized in that: The steps include: S1) During the sinking of the caisson, if it is found that the caisson is difficult to sink, then go to step S2); if it is found that the caisson is tilted, then go to step S3); if the caisson is sealed underwater, then go to step S4); S2) digging sand filling grooves (7) around the caisson on the ground (9), filling them with sandy friction reducing materials (8), and implementing sand filling to aid sinking; and / or introducing high-pressure compressed air into the air curtain riser (10), implementing air curtain to aid sinking, and observing the sinking of the caisson; If the caisson still sinks too slowly or cannot sink, a Bailey frame (2) is installed on the edge of the caisson to form a loading platform, and static pressure is used to assist the sinking until the uniform load applied to the Bailey frame (2) is greater than the frictional resistance between the caisson wall (1) and the soil, and the caisson resumes normal sinking; If the sinking speed of the caisson returns to normal, there is no need to install the Bailey frame (2) on the edge of the caisson; S3) If the sand filling assisted sinking, air curtain assisted sinking, and static pressure assisted sinking construction in the above step S2) are not carried out at this time, a Bailey frame (2) is installed on the edge of the caisson to form a loading platform, and static pressure correction measures are taken. The Bailey frame (2) is continuously loaded with uneven loads to make the caisson tilt in the opposite direction until the caisson posture is restored and continues to sink normally; If the sand filling, air curtain and static pressure assisted sinking in step S2) have been carried out, the air curtain assisted sinking measure is stopped and static pressure correction measures are carried out. The Bailey frame (2) continuously unloads the uneven load to make the caisson tilt in the opposite direction until the caisson recovers and continues to sink normally. S4) Bailey frames (2) are installed on the edge of the caisson to form a working platform; the number and length of anchoring steel bars (5) are determined according to the design, and a flexible steel wire mesh (6) is woven to fix vertical anchoring steel bars (5) at each node on the horizontal mesh; a steel wire rope (4) is arranged on the top of each anchoring steel bar (5); the steel wire mesh (6) is lifted by the steel wire rope (4) and lowered to the designed height; the top of the steel wire rope (4) is fixed to the Bailey frame (2), and underwater bottom sealing concrete (14) is poured, and the water stored at the bottom of the well is drained to complete the underwater bottom sealing construction of the caisson.

8. The method for sinking a caisson and sealing the bottom underwater according to claim 7, characterized in that: In S2), the static pressure-assisted sinking measure is specifically to use a crane to pile the bagged soil (3) on the Bailey frame (2) in a uniform, symmetrical and layered manner, and continue to load the bagged soil (3) until the applied load is greater than the frictional resistance between the caisson wall (1) and the soil, and the caisson resumes normal sinking.

9. The method for sinking a caisson and sealing the bottom underwater according to claim 8, characterized in that: In S3), when the sand filling assisted sinking, air curtain assisted sinking, and static pressure assisted sinking construction are not carried out, the static pressure correction measures are specifically to use a crane to pile bagged soil (3) on the Bailey frame (2), and pile it in the opposite direction of the tilting direction, and continue to load until the uneven load causes the caisson to tilt in the opposite direction, and adjust the amount of bagged soil according to the posture of the caisson until the posture of the caisson is restored and it continues to sink normally; When sand filling to assist sinking, air curtain to assist sinking, and static pressure to assist sinking have been carried out, the static pressure correction measures are specifically to use a crane to unload the bagged soil (3) in the tilted direction, and continue to unload until the uneven load applied causes the caisson to tilt in the opposite direction, and adjust the amount of bagged soil according to the posture of the caisson until the posture of the caisson is restored and it continues to sink normally.

10. The method for sinking a caisson and sealing the bottom underwater according to claim 9, characterized in that: In S4), when the top end of the steel wire rope (4) is fixed to the Bailey frame (2), the fixing position of the steel wire rope (4) and the Bailey frame (2) is adjusted on the Bailey frame (2), so that the steel wire mesh (6) is unfolded according to the design requirements, ensuring that the spacing of the anchor steel bars (5) meets the design requirements.

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