Deep and large caisson drag reduction and sinking assistance system and coordinated control method

Abstract

The present invention relates to the field of geotechnical engineering construction, and specifically to a deep and large caisson drag reduction and sinking aid system and a coordinated control method. The system includes a formation information library that stores formation information corresponding to each well wall partition; a posture monitoring module for real-time acquisition of the caisson's control point coordinates, control point elevation, deflection, well bottom elevation, well water level, surrounding strata, sinking speed, and blade foot resistance; a thixotropic mud drag reduction module that can independently control the mud viscosity of each well wall partition; a high-pressure jet flow sinking aid module that can independently control the injection pressure of each well wall partition; and a counterweight adjustment module that can adjust the counterweight loading. The present invention covers self-weight sinking, thixotropic mud drag reduction, high-pressure jet flow sinking aid, and counterweight sinking aid, and can achieve coordinated control of each drag reduction and sinking aid system, which can greatly improve the construction efficiency of deep and large caissons penetrating hard soil layers, solve the pain points of poor geological adaptability, multi-system coordination difficulties, and high accident rates in caisson construction, and improve construction quality.

Description

Technical Field

[0001] The present invention relates to the field of geotechnical engineering construction, and in particular to a deep and large caisson drag reduction and sinking assistance system and a coordinated control method. Background Art

[0002] Currently, traditional caissons are prone to sinking difficulties during construction. Drag reduction and sinking aid systems rely on engineering experience, which can cause sudden sinking, deflection, and even stagnant sinking. For example, a large, deep caisson was constructed using an undrained sinking process. During the sinking process, they encountered a hard plastic viscosity layer up to 7 meters thick. They used a combination of deadweight sinking and thixotropic slurry sinking method, but when the hard plastic clay layer became thick, sinking stalled and became impossible. They had to install a water-blocking curtain outside the well and switch to dry excavation, increasing construction costs and timelines. Current large, deep caissons suffer from an imperfect drag reduction and sinking aid system, and their attitude and sinking speed control rely on engineering experience, resulting in low reliability in construction costs and timelines. Summary of the Invention

[0003] The purpose of the present invention is to overcome the shortcomings in the prior art such as the difficulty in sinking control, the independent operation of the drag reduction and sinking aid systems, the inability to be controlled in a linkage manner, and the susceptibility to difficulties in sinking, sudden sinking, and deflection. A deep and large caisson drag reduction and sinking aid system and a collaborative control method are provided, which covers deadweight, thixotropic mud drag reduction, high-pressure jet flow sinking and counterweight sinking, and can realize intelligent regulation and collaborative control of each drag reduction and sinking aid system.

[0004] In a first aspect, the present invention provides a deep caisson drag reduction and sinking assistance system, comprising:

[0005] The formation information database stores the formation information corresponding to each well wall partition;

[0006] The posture monitoring module is used to obtain the coordinates of the caisson's control points, control point elevation, deflection, bottom elevation, water level in the well, surrounding strata, sinking speed, and blade resistance in real time;

[0007] A thixotropic mud drag reduction module can be activated when the caisson sinking speed is less than the warning lower limit, and can independently control the mud viscosity of each well wall partition based on the formation information database and information provided by the posture monitoring module;

[0008] A high-pressure jet flow sinking aid module can be activated when the sinking speed of the caisson is less than the warning lower limit after the thixotropic mud drag reduction module is activated, and can independently control the jet pressure of each well wall partition based on the information provided by the formation information library and the posture monitoring module;

[0009] The counterweight adjustment module can be activated when the sinking speed of the caisson is less than the warning lower limit after the high-pressure jet flow sinking aid module is activated, and can adjust the counterweight loading amount.

[0010] Preferably, the stratum information in the stratum information database can be updated in real time according to the geological conditions revealed by actual excavation during construction.

[0011] Preferably, the thixotropic mud drag reduction module includes a grouting pipe buried in each well wall partition and an independently controllable electric regulating valve.

[0012] Preferably, the high-pressure jet flow assisted sinking module includes a high-pressure jet pipeline and a rotating jet nozzle connected to each other, the high-pressure jet pipeline is pre-buried in the well wall, and the rotating jet nozzle is arranged at the bottom end of the caisson blade foot.

[0013] Preferably, the high-pressure jet flow assisted sinking module also includes a sensor array, a central controller, a high-pressure water pump group, and an energy storage and pressure stabilizing tank. The sensor array can monitor the grouting pressure, the high-pressure water pump group is connected to the energy storage and pressure stabilizing tank, and the energy storage and pressure stabilizing tank is connected to the high-pressure jet pipeline. The central controller is used to control the opening and closing of the rotating jet nozzle.

[0014] Preferably, the counterweight adjustment module includes a plurality of sealed chambers, which are arranged at the top of the caisson, and the water levels of the sealed chambers can be adjusted.

[0015] In a second aspect, the present invention provides a method for coordinated control of drag reduction and sinking assistance in a deep and large caisson, comprising the following steps:

[0016] S1: Divide the caisson into a plurality of well wall partitions, and store the stratigraphic information of each well wall partition into the stratigraphic information database;

[0017] S2: Start the posture monitoring module to obtain the coordinates of the control points, the elevation of the control points, the deflection, the elevation of the bottom of the well, the water level in the well, the surrounding strata, the sinking speed, and the blade foot resistance of the caisson in real time;

[0018] S3: sinking by self-weight;

[0019] S4: When the sinking speed of the caisson is less than the warning lower limit, the thixotropic mud drag reduction module is activated to independently control the mud viscosity of each well wall partition according to the formation information database and the information provided by the attitude monitoring module;

[0020] S5: when the sinking speed of the caisson is less than the warning lower limit after the thixotropic mud drag reduction module is activated, the high-pressure jet flow assisting sinking module is activated, and the jet pressure of each well wall partition is independently controlled according to the formation information database and the information provided by the posture monitoring module;

[0021] S6: After the high-pressure jet flow sinking aid module is started, when the sinking speed of the caisson is less than the warning lower limit value, the counterweight adjustment module is started to increase the counterweight loading amount according to the gradient.

[0022] Preferably, the adjustment method of the thixotropic mud drag reduction module is:

[0023] S41: Set the viscosity reference value of thixotropic mud , sinking speed reference value ;

[0024] S42: According to the actual sinking speed Adjust viscosity change , when the actual sinking speed When the actual sinking speed is greater than the upper limit of the warning, the viscosity enhancer is injected to increase the viscosity. When the sinking speed is less than the lower limit of the warning, water is injected to reduce the viscosity.

[0025] Preferably, the counterweight adjustment module is loaded with 20% to 30% of the sealed chamber volume for the first time, and subsequently increases the sealed chamber volume by 10% to 15% each time.

[0026] Preferably, the thixotropic mud drag reduction module is automatically started when the sinking speed does not reach the target value within 10 to 30 minutes when the deadweight sinking is enabled; the high-pressure jet stream sinking aid module is automatically started when the sinking speed does not reach the target value within 10 to 30 minutes when the thixotropic mud drag reduction module is enabled; the counterweight adjustment module is automatically started when the sinking speed does not reach the target value within 10 to 30 minutes when the high-pressure jet stream sinking aid module is enabled.

[0027] It should be noted that the deep and large caisson mentioned in the present invention refers to a caisson with a diameter greater than 8m and a depth greater than 15m.

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] The present invention provides a drag reduction and sinking aiding system for deep and large caissons and a coordinated control method, which covers sinking by deadweight, thixotropic mud drag reduction, high-pressure jet flow sinking and counterweight sinking, and can realize intelligent regulation and coordinated control of each drag reduction and sinking aiding system, thereby realizing the smooth sinking of deep and large caissons.

[0030] The present invention can greatly improve the construction efficiency of deep and large caissons penetrating hard soil layers, solve the pain points of poor geological adaptability, difficulty in multi-system coordination, and high accident rate in traditional caisson construction, and improve construction quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 This is a framework diagram of the deep caisson drag reduction and sinking assistance system described in the present invention.

[0032] Figure 2 This is an operation flow chart of the thixotropic mud drag reduction module diagram described in the present invention.

[0033] Figure 3This is a system composition diagram of the high-pressure jet flow sinking aid module described in the present invention.

[0034] Figure 4 This is a flow chart of the coordinated control method for reducing drag and assisting sinking in deep and large caissons described in the present invention. DETAILED DESCRIPTION

[0035] The present invention will be further described in detail below with reference to specific embodiments. However, this should not be construed as limiting the scope of the present invention to the following embodiments, as all technologies implemented based on the present invention fall within the scope of the present invention.

[0036] Unless otherwise specified, in the description of the specific embodiments of the present invention, the terms indicating orientation or positional relationships such as "upper," "lower," "left," "right," "center," "inside," and "outside" are based on the orientation or positional relationships shown in the accompanying drawings, or are the orientation or positional relationships in which the invented product / device / apparatus is placed when it is conventionally used. These terms of orientation or positional relationships are merely for the purpose of facilitating the description of the present invention or simplifying the description of the specific embodiments to facilitate a quick understanding of the solutions by technicians, and do not indicate or imply that a particular device / component / element must have a specific orientation or be constructed and operated in a specific positional relationship. Therefore, they should not be construed as limitations on the present invention.

[0037] In addition, the use of terms such as "horizontal," "vertical," "overhanging," "parallel," and "coaxial" does not necessarily require that the corresponding devices / components / elements be absolutely horizontal, vertical, overhanging, parallel, or coaxial. Instead, they may be slightly tilted or have deviations, as long as they do not affect the normal function of the relevant components. For example, "horizontal" simply means that its direction is more horizontal than "vertical," and does not mean that the structure must be completely horizontal, but rather that it can be slightly tilted. "Coaxial" means that the two components are arranged as coaxially as possible, so that they move in a coaxial or approximately coaxial manner when their relative positions change. Alternatively, it can be simplified to mean that the corresponding devices / components / elements are arranged in a "horizontal," "vertical," "overhanging," "parallel," or "coaxial" direction, and can have an error / deviation of ±10% relative to the corresponding direction, more preferably within an error / deviation of ±8%, more preferably within an error / deviation of ±6%, more preferably within an error / deviation of ±5%, and more preferably within an error / deviation of ±4%. For example, the deviation in the "coaxial" direction is controlled within 0.2-1mm, preferably within 0.2-0.5mm. As long as the corresponding device / component / element is within the error / deviation range, it can still achieve its role in the solution of the present invention.

[0038] In addition, the expressions “first”, “second”, “third”, etc. in the terms are merely used to distinguish the description of the same or similar components, and should not be understood as emphasizing or implying the relative importance of specific components.

[0039] In addition, in the description of the embodiments of the present invention, "several," "a plurality," and "a number" represent at least two. It can also be any number such as two, three, four, five, six, seven, eight, nine, or even more than nine.

[0040] Furthermore, in the description of the technical solution of the present invention, unless otherwise expressly specified, defined, or limited, the terms "disposed," "installed," "connected," "connected," "provided with," "laid," and "arranged" should be understood broadly. For example, they may refer to fixed connections, detachable connections, or integral connections. They may be welded, riveted, bolted, threaded, or other commonly used connection methods in the art. Such connections may be mechanical, electrical, or communicative; they may be direct, indirect via an intermediate medium, or internally connected between two components.

[0041] Example 1

[0042] like Figure 1 As shown, a deep caisson drag reduction and sinking aid system includes a formation information library, a posture monitoring module, a thixotropic mud drag reduction module, a high-pressure jet flow sinking aid module and a counterweight adjustment module.

[0043] The stratum information database stores stratum information corresponding to each wellbore partition. Based on detailed survey data, the stratum distribution and physical and mechanical parameters surrounding the wellbore are entered into the database. Each wellbore partition has corresponding stratum information. The database is also updated based on geological conditions revealed during construction, enabling adjustments to thixotropic mud, high-pressure jet flow, and counterweights to be made according to the different strata during construction.

[0044] The attitude monitoring module is used to obtain real-time information about the caisson's control point coordinates, control point elevations, deflection, bottom elevation, water level, surrounding strata, sinking speed, and blade resistance. Operators can dynamically adjust drag reduction and sinking assistance measures for each caisson wall section based on this real-time information.

[0045] The thixotropic mud drag reduction module can be activated when the caisson sinking speed is less than the warning lower limit, and can independently control the mud viscosity of each well wall partition based on the formation information database and the information provided by the posture monitoring module. For example, the well wall is divided into 8 to 12 sector-shaped well wall partitions, each well wall partition is buried with a grouting pipe, and is equipped with an independently controllable electric regulating valve, and each well wall partition is independently controlled. When sinking is difficult relying on the deadweight of the well wall, the thixotropic mud drag reduction module is activated when the sinking speed is less than the warning lower limit, and thixotropic mud is injected into the outer periphery of the well wall to reduce the friction between the well wall and the soil layer. The mud viscosity can also be adjusted based on the sinking speed feedback result measured by the sinking speed sensor.

[0046] The high-pressure jet flow sinking assistance module can be activated when the sinking speed of the caisson is less than the warning lower limit after the thixotropic mud drag reduction module is activated, and can independently control the injection pressure of each well wall partition based on the information provided by the formation information library and the posture monitoring module.

[0047] In one or more preferred embodiments, Figure 3 As shown, the high-pressure jet flow assisted sinking module includes a sensor array, a central controller, a high-pressure water pump group, an energy storage and pressure regulating tank, a high-pressure jet pipeline and a rotating jet nozzle. The sensor array can monitor the grouting pressure, the high-pressure water pump group is connected to the energy storage and pressure regulating tank, the energy storage and pressure regulating tank is connected to the high-pressure jet pipeline, the high-pressure jet pipeline is connected to the rotating jet nozzle, the high-pressure jet pipeline is pre-buried in the well wall, and the rotating jet nozzle is arranged at the bottom end of the caisson blade. The central controller can control the opening and closing of the rotating jet nozzle. In the preferred solution, the central controller can control the opening and closing of the high-pressure water pump group. In the preferred solution, the rotating jet nozzle adopts a rotatable alloy nozzle, and the jet pressure can be steplessly adjusted within the range of 20MPa-50MPa.

[0048] The counterweight adjustment module can be activated when the caisson's sinking speed falls below the warning lower limit after the high-pressure jet flow assist module is activated. The counterweight adjustment module can adjust the counterweight loading. In a preferred embodiment, multiple water-filled sealed chambers are provided at the top of the caisson. The volume of the sealed chambers is calculated based on the required sinking force of the caisson, and the water level in the sealed chambers can be adjusted.

[0049] The deep and large caisson drag reduction and sinking aid system described in the present invention includes a thixotropic mud drag reduction module, a high-pressure jet flow sinking aid module and a counterweight adjustment module. It can adjust the drag reduction and sinking aid measures of each well wall partition according to the information of the formation information library and the attitude monitoring module to achieve linkage control, solving the industry pain points of poor geological adaptability, difficulty in multi-system coordination, and high accident rate in traditional caisson construction, which can improve construction efficiency, save energy consumption and improve construction quality.

[0050] Example 2

[0051] like Figure 4 As shown, a coordinated control method for reducing drag and aiding sinking in a deep and large caisson is provided, which uses the deep and large caisson drag reduction and aiding sinking system as described in Example 1, and includes the following steps:

[0052] S1: Divide the caisson into a plurality of well wall partitions, store the stratigraphic information of each well wall partition into the stratigraphic information database, and update the stratigraphic information database according to the geological conditions revealed by actual excavation during construction;

[0053] S2: Start the posture monitoring module to obtain the coordinates of the control points, the elevation of the control points, the deflection, the elevation of the bottom of the well, the water level in the well, the surrounding strata, the sinking speed, and the blade foot resistance of the caisson in real time;

[0054] S3: sinking by self-weight;

[0055] S4: When the caisson sinking velocity falls below the lower warning threshold, the thixotropic mud drag reduction module is activated. Based on information provided by the formation information database and the attitude monitoring module, the slurry viscosity in each wellbore section is independently controlled. In a preferred embodiment, during construction, the viscosity and injection rate of the thixotropic mud can be adjusted based on the sinking of each wellbore section to control deflection.

[0056] In one or more embodiments, Figure 2 As shown, the adjustment method of the thixotropic mud drag reduction module is:

[0057] S41: Set the viscosity reference value of thixotropic mud , sinking speed reference value , sinking speed warning lower limit value, sinking speed warning upper limit value;

[0058] S42: According to the actual sinking speed Adjust viscosity change , when the actual sinking speed When the sinking speed is greater than the upper limit of the warning, the viscosity enhancer is injected to increase the viscosity. In the preferred solution, the viscosity after the increase is required to be no more than 50s. When the actual sinking speed is When the sinking speed is less than the lower limit of the warning, water is injected to reduce the viscosity. In the preferred solution, the viscosity after reduction is required to be no less than 25s.

[0059] Thickener addition amount Calculated according to the following formula:

[0060] ,

[0061] Where, V is the effective volume of the mud pool, , Krepresents the response coefficient, which is 0.8 for clay soil and 1.2 for sandy soil; is the formation correction factor, which is 0.7 for clay, 1.0 for silty clay, 1.3 for silt sand, and 1.5 for gravel;

[0062] Water addition amount Calculated according to the following formula:

[0063] ,

[0064] Where, is the dilution coefficient, which is 1.8 for clay soil and 1.2 for sandy soil. is the current viscosity value, is the viscosity target value, the minimum viscosity target value should not be less than 25s, V is the effective volume of the mud pool.

[0065] After increasing the viscosity, continue to monitor whether the sinking speed reaches the target value. If not, continue to increase the viscosity until the viscosity reaches the upper limit. If the sinking speed still does not reach the target value after the viscosity reaches the upper limit, take measures such as unloading the counterweight and increasing the support at the bottom of the blade foot.

[0066] After adding water, the sinking speed reaches the expected target and the current viscosity is maintained. If the expected sinking speed is not reached, the inspection procedure should be started to check whether the mud sleeve is damaged. If damaged, inject plugging slurry; check whether the formation has changed. If the change is large, readjust the formation parameters; if the blade foot resistance is too large, start the high-pressure jet flow sinking aid module to cut the blade foot soil.

[0067] S5: After the thixotropic mud drag reduction module is activated, if the sinking speed of the caisson falls below the lower warning limit, the high-pressure jet flow assist module is activated. Based on information provided by the formation information database and the posture monitoring module, the jet pressure of each wellbore section is independently controlled. In a preferred embodiment, the rotating jet nozzles may be activated in batches at intervals.

[0068] When the grouting pressure suddenly increases significantly, the high-pressure jetting in the area should be stopped immediately, and the pipeline should be checked for blockage. The blockage should be cleared and the process should be restarted.

[0069] S6: After activating the high-pressure jet-assisted sinking module, if the caisson sinking speed falls below the lower warning threshold, the counterweight adjustment module is activated to gradually increase the counterweight loading. In a preferred embodiment, the counterweight adjustment module initially loads 20%-30% of the sealed chamber (water tank) volume, and subsequently increases the volume by 10%-15%. The counterweight should be added or removed in stages, and the caisson should be observed for 10-30 minutes after each addition or removal. If the desired sinking speed is not achieved, the counterweight should be added or removed again, and observed for another 10-30 minutes until the desired sinking position is reached.

[0070] In one or more preferred embodiments, the coordinated control method process of the caisson sinking aid system is as follows: sinking by dead weight → thixotropic mud drag reduction → high-pressure water jet sinking → counterweight loading, and when the sinking speed does not reach the target value within 10 to 30 minutes after the current level of measures is activated, the next level is automatically activated. That is, when the sinking speed does not reach the target value within 10 to 30 minutes after the dead weight sinking is activated, the thixotropic mud drag reduction module is automatically activated; when the sinking speed does not reach the target value within 10 to 30 minutes after the thixotropic mud drag reduction module is activated, the high-pressure jet sinking aid module is automatically activated; and when the sinking speed does not reach the target value within 10 to 30 minutes after the high-pressure jet sinking aid module is activated, the counterweight adjustment module is automatically activated.

[0071] The coordinated control method for reducing drag and assisting sinking of deep and large caissons described in the present invention can greatly improve the construction efficiency of deep and large caissons penetrating hard soil layers. Through time sequence triggering, waste can be avoided, and the overall energy consumption is reduced. The caisson posture control accuracy reaches 1%, and the correction response time is less than 2 minutes.

[0072] Example 3

[0073] Based on Example 1 and Example 2, this example specifically describes the construction of a working shaft and caisson in a municipal pipe-jacking river crossing project.

[0074] In a municipal pipe-jacking project across a river, the working well was constructed using a caisson. The caisson had a diameter of 20.8m and a depth of 33.5m. The strata that the caisson crossed were, from top to bottom, mainly fill, silty clay, medium sand, fine sand, medium sand, coarse sand, clay, medium sand, and mudstone. The clay layer was hard plastic and had high strength. The groundwater level was buried at a depth of approximately 2m. The undrained sinking method was used for construction. To ensure the smooth sinking of the caisson, a thixotropic mud drag reduction module was installed on the periphery of the caisson wall, and a high-pressure jet grouting pipeline was pre-buried at the blade foot. The specific implementation steps are as follows:

[0075] 1. Pre-buried thixotropic mud pipelines and high-pressure jet pipelines in the caisson wall, and pre-buried rotating jet nozzles under the blade foot;

[0076] 2. Install sensors in the caisson structure to monitor the coordinates, elevation, deflection, sinking speed, and blade resistance of each caisson control point to collect real-time information;

[0077] 3. In the initial stage, the sinking is done by its own weight;

[0078] 4. Set the baseline sinking speed The lower limit of the sinking speed warning is 0.25mm / min, and the upper limit of the sinking speed warning is 0.75mm / min. When the actual monitored sinking speed If the speed is less than 0.25 mm / min and lasts for 15 minutes, the thixotropic mud drag reduction module is activated;

[0079] 5. Set the initial viscosity of the thixotropic mud to 35s and the grouting pressure to 0.5MPa, start the thixotropic mud drag reduction nozzles in all zones to inject mud into the formation around the caisson;

[0080] 6. During construction, the viscosity of the thixotropic mud can be dynamically adjusted according to the caisson posture. When crossing the sand layer, if the sinking speed reaches 0.8mm / min and exceeds the warning upper limit, the viscosity of the mud will be increased to control the situation. The specific implementation method is as follows:

[0081] 1) Calculate viscosity increment : The response coefficient K of sand is 1.2, and the formation correction coefficient of sand layer is Take 1.3, the actual value of sinking speed Take 0.75mm / min, and the sinking speed reference value is 0.5mm / min, then

[0082]

[0083] 2) Calculate the amount of thickener added :Using carboxymethyl cellulose as viscosity enhancer, the effective volume of the mud pool is 20m³, then

[0084] ,

[0085] After the increase, the mud viscosity is adjusted to 45s; observe whether the sinking speed has dropped to near the baseline value. If not, continue to adjust the viscosity. When the viscosity increases to 50s, it should not be further increased to prevent pumping difficulties. Instead, take the next step, such as adding weights or activating a high-pressure jet flow sinking aid module. When crossing the viscosity section, the sinking speed is reduced to 0.15mm / min, which is less than the lower limit of the sinking speed warning. The method of increasing the amount of water is used to reduce the viscosity and speed up the sinking speed. The specific calculation method for the amount of water added is:

[0086]

[0087] in, is the dilution coefficient, which is 1.8 for clay soil; is the current viscosity value, take 40; The target viscosity value is 25s, and the effective volume V of the mud pool is 20m 3 Water can be added in batches. Stir each time and wait for about 15 minutes to test the viscosity. Stop when the viscosity reaches the target value. Otherwise, continue adding water until the viscosity reaches the target value. After the viscosity decreases, continue to observe whether the sinking speed increases to the baseline value.

[0088] 7. When all the thixotropic mud drag reduction modules are activated and the mud viscosity adjustment has reached the lower limit, if the sinking speed of the caisson is still decreasing and the duration exceeds 10 to 30 minutes, the high-pressure jet flow sinking aid module is activated.

[0089] The high-pressure jet-assisted sinking module is activated in batches based on the caisson's posture. For example, in this project, 48 rotatable nozzles were embedded at the base of the blade foot, divided into 12 zones. The nozzle outlet diameter is 2.5 mm, and the pressure can be adjusted between 20 and 50 MPa. Each nozzle can be turned on and off independently, and different pressures can be set for each zone. During construction, 12 nozzles, representing 1 / 4 of the total, were activated initially, and the remaining nozzles were activated in batches based on the sinking speed.

[0090] After adopting this system, the caisson was successfully sunk to the predetermined elevation, ensuring the construction period.

[0091] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A deep caisson drag reduction and sinking aid system, characterized in that: include: The formation information database stores the formation information corresponding to each well wall partition; The posture monitoring module is used to obtain the coordinates of the caisson's control points, control point elevation, deflection, bottom elevation, water level in the well, surrounding strata, sinking speed, and blade resistance in real time; A thixotropic mud drag reduction module can be activated when the caisson sinking speed is less than the warning lower limit, and can independently control the mud viscosity of each well wall partition based on the formation information database and information provided by the posture monitoring module; A high-pressure jet flow sinking aid module can be activated when the sinking speed of the caisson is less than the warning lower limit after the thixotropic mud drag reduction module is activated, and can independently control the jet pressure of each well wall partition based on the information provided by the formation information library and the posture monitoring module; The counterweight adjustment module can be activated when the sinking speed of the caisson is less than the warning lower limit after the high-pressure jet flow sinking aid module is activated, and can adjust the counterweight loading amount.

2. The deep caisson drag reduction and sinking aid system according to claim 1 is characterized in that: The stratum information in the stratum information database can be updated in real time according to the geological conditions revealed by actual excavation during construction.

3. The deep caisson drag reduction and sinking aid system according to claim 1 is characterized in that: The thixotropic mud drag reduction module includes a grouting pipe buried in each well wall partition and an independently controllable electric regulating valve.

4. The deep caisson drag reduction and sinking aid system according to claim 1 is characterized in that: The high-pressure jet flow assisted sinking module includes a high-pressure jet pipeline and a rotating jet nozzle that are interconnected. The high-pressure jet pipeline is pre-buried in the well wall, and the rotating jet nozzle is arranged at the bottom end of the caisson blade foot.

5. The deep caisson drag reduction and sinking aid system according to claim 4 is characterized in that: The high-pressure jet flow assisted sinking module also includes a sensor array, a central controller, a high-pressure water pump group, and an energy storage and pressure stabilizing tank. The sensor array can monitor the grouting pressure, the high-pressure water pump group is connected to the energy storage and pressure stabilizing tank, and the energy storage and pressure stabilizing tank is connected to the high-pressure jet pipeline. The central controller is used to control the opening and closing of the rotating jet nozzle.

6. The deep caisson drag reduction and sinking aid system according to claim 1 is characterized in that: The counterweight adjustment module includes a plurality of sealed chambers, which are arranged at the top of the caisson, and the water levels of the sealed chambers can be adjusted.

7. A coordinated control method for reducing drag and assisting sinking in deep and large caissons, characterized in that: The deep caisson drag reduction and sinking aid system according to any one of claims 1 to 6 is used, comprising the following steps: S1: Divide the caisson into a plurality of well wall partitions, and store the stratigraphic information of each well wall partition into the stratigraphic information database; S2: Start the posture monitoring module to obtain the coordinates of the control points, the elevation of the control points, the deflection, the elevation of the bottom of the well, the water level in the well, the surrounding strata, the sinking speed, and the blade foot resistance of the caisson in real time; S3: sinking by self-weight; S4: When the sinking speed of the caisson is less than the warning lower limit, the thixotropic mud drag reduction module is activated to independently control the mud viscosity of each well wall partition according to the formation information database and the information provided by the attitude monitoring module; S5: when the sinking speed of the caisson is less than the warning lower limit after the thixotropic mud drag reduction module is activated, the high-pressure jet flow assisting sinking module is activated, and the jet pressure of each well wall partition is independently controlled according to the formation information database and the information provided by the posture monitoring module; S6: After the high-pressure jet flow sinking aid module is started, when the sinking speed of the caisson is less than the warning lower limit value, the counterweight adjustment module is started to increase the counterweight loading amount according to the gradient.

8. The coordinated control method for reducing drag and assisting sinking in deep and large caissons according to claim 7 is characterized in that: The adjustment method of the thixotropic mud drag reduction module is: S41: Set the viscosity reference value of thixotropic mud , sinking speed reference value ; S42: According to the actual sinking speed Adjust viscosity change , when the actual sinking speed When the sinking speed is greater than the upper limit of the warning, a viscosity enhancer is injected to increase the viscosity; When the actual sinking speed When the sinking speed is less than the lower limit of the warning, water is injected to reduce the viscosity.

9. The coordinated control method for reducing drag and assisting sinking in deep and large caissons according to claim 8 is characterized in that: The counterweight adjustment module is initially loaded with 20% to 30% of the sealed chamber volume, and subsequently increases the sealed chamber volume by 10% to 15% each time.

10. The method for coordinated control of drag reduction and sinking assistance in deep and large caissons according to any one of claims 7 to 9, characterized in that: When the sinking speed does not reach the target value within 10 to 30 minutes after the deadweight sinking is enabled, the thixotropic mud drag reduction module is automatically started; when the sinking speed does not reach the target value within 10 to 30 minutes after the thixotropic mud drag reduction module is enabled, the high-pressure jet stream sinking aid module is automatically started; when the sinking speed does not reach the target value within 10 to 30 minutes after the high-pressure jet stream sinking aid module is enabled, the counterweight adjustment module is automatically started.

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