A method for controlling the sinking construction of double-walled steel cofferdam without bottom in deep-water bare rock geology

Abstract

The present invention belongs to the technical field of cofferdam construction control, and specifically discloses a deep-water bare rock geological bottomless double-wall steel cofferdam sinking construction control method, the method comprising: collecting bare rock characteristic data and water body characteristic data of the construction area, and collecting information of the cofferdam, the information being size, shape, weight and surface roughness; confirming the auxiliary sinking mode switching point and confirming the starting construction time period; real-time monitoring of the state information during the sinking process, making a sinking adjustment judgment, and when the judgment result is adjustment, confirming the current adjustment sinking information, and when the judgment result is no adjustment, continuing to execute the sinking; controlling the steel cofferdam sinking construction process, and returning to the previous step while implementing control measures until the cofferdam is installed. The present invention can fully grasp the hydrological characteristics and changes of the construction waters, and at the same time realizes multi-link linkage control during the sinking adjustment, greatly improving the construction efficiency and construction accuracy of the cofferdam.

Description

Technical Field

[0001] The invention belongs to the technical field of cofferdam construction control, and in particular relates to a method for controlling the sinking construction of a double-walled steel cofferdam with no bottom in deep-water bare rock geology. Background Art

[0002] With the development of transportation infrastructure, many cross-river and cross-sea bridge projects have emerged. The underwater geology of some waters is bare rock and the water depth is relatively large. When constructing bridge foundations, a reliable cofferdam structure is required to create a dry construction environment. Double-walled steel cofferdams are often selected due to their good structural strength, waterproofness and stability. Their sinking construction in deep-water bare rock geology is crucial to ensure the smooth progress of bridge foundation construction.

[0003] Prior art, such as the deepwater double-walled steel cofferdam and its sinking construction method disclosed in the Chinese invention patent application with application number 202411409386.1, includes factory prefabrication of double-walled steel cofferdam blocks, on-site hoisting and splicing, sinking and implantation of steel cofferdam, deviation and inclination correction of steel cofferdam, concrete pouring in the wall cavity and bottom concrete pouring, and internal cleaning of steel cofferdam. When correcting the deviation, the concentrated excavation method and backfilling sand and gravel method are used to correct the deviation of the double-walled steel cofferdam, and the underwater jacking method and mud suction method are used to correct the inclination of the double-walled steel cofferdam. When the deviation is greater than the threshold, the steel cofferdam is lifted and sunk again, thereby realizing the precise processing of steel cofferdam components, reducing the difficulty of assembly, improving the sinking efficiency and control accuracy of the cofferdam, and being applicable to complex underwater environments, and ensuring the stability and bearing capacity of the deepwater cofferdam structure.

[0004] Another example of the prior art is the double-walled steel cofferdam and construction method for deep-water rock capping rotary trenching without bottom cover disclosed in the Chinese invention patent application with application number 202411433540.9. By adopting BIM three-dimensional simulation technology, the size of the cofferdam module and the position of the preset holes can be accurately designed, which greatly improves the accuracy and efficiency of the construction. By solving the problems of module size and layout in the design stage, the installation and commissioning work on site can be significantly reduced, thereby speeding up the construction progress and ensuring the quality of the project. At the same time, the quick connection method of prestressed tendons and extruded waterproof strips is adopted between the cofferdam modules, which saves a lot of welding work, not only improves the construction efficiency but also reduces the construction difficulty. The guide device used for the lowering of the cofferdam is used for horizontal, vertical displacement and inclination monitoring, which can help the cofferdam lowering process more accurately, and greatly improve the construction efficiency and safety. The comprehensive slotting method of impact drill, rotary drilling drill and grab bucket greatly improves the slotting efficiency and reduces the slotting difficulty.

[0005] With regard to the above technical solutions, it is obvious that the current deepwater bare rock geology bottomless double-wall steel cofferdam sinking construction still has the following deficiencies in the control process: 1. The steel cofferdam sinking construction is basically a combination of multiple sinking methods. Currently, there is insufficient attention paid to the timing of switching between different sinking methods, resulting in insufficient control of the key timing when combining multiple sinking methods for construction, making it difficult to ensure the tightness and smoothness of the connection between the sinking stages, and also adding additional adjustment time and construction complexity.

[0006] 2. Although the BIM three-dimensional simulation technology is currently used to accurately design the size of the cofferdam module and the position of the preset holes, the method in the subsequent sinking control process is relatively single and has certain limitations. The deflection of the steel cofferdam is often caused by the combined effect of multiple complex factors, involving multi-link joint control correction. It is currently difficult to deal with various causes of deflection more comprehensively and effectively and achieve an ideal correction effect, which results in a certain deviation in the improvement of construction efficiency and construction accuracy. Summary of the invention

[0007] In view of this, in order to solve the problems raised in the above background technology, a method for controlling the sinking construction of a double-walled steel cofferdam without a bottom in deep-water bare rock geology is proposed.

[0008] The purpose of the present invention can be achieved through the following technical solutions: The present invention provides a method for controlling the sinking construction of a double-walled steel cofferdam without a bottom in deep-water bare rock geology, the method comprising: S1, data collection and preparation: collecting bare rock characteristic data and water characteristic data in the construction area, and collecting information on the cofferdam, the information being size, shape, weight and surface roughness.

[0009] S2. Preliminary formulation of sinking plan: Based on the bare rock characteristic data, water body characteristic data and cofferdam information collected in step S1, confirm the switching point of the auxiliary sinking method and confirm the starting construction time period.

[0010] S3. Sinking execution and adjustment confirmation: monitor the status information of the sinking process in real time, and make a judgment on the sinking adjustment. When the judgment result is adjustment, confirm the current adjustment sinking information. When the judgment result is no adjustment, continue to execute the sinking.

[0011] S4, sinking process control: Based on the current adjusted sinking information, the sinking construction process of the steel cofferdam is controlled. While implementing the control measures, return to step S3 until the cofferdam installation is completed.

[0012] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) The present invention can comprehensively grasp the hydrological characteristics and their changes of the construction water area by calculating the differences and means of the water level heights, water flow velocities, and water height differences in different monitoring time periods and different monitoring days, and then confirming the starting construction time period, so as to select the construction time when all conditions are relatively stable and conducive to the sinking construction of double-walled steel cofferdams without bottom in deep-water bare rock geology, laying a good foundation for the smooth progress of the entire construction process.

[0013] (2) The present invention analyzes the feasibility of the cofferdam's self-weight sinking at various depths and the feasibility of its self-weight crossing at various calibrated monitoring raised positions to determine the switching point of the auxiliary sinking mode, thereby effectively solving the current problem of insufficient attention to the timing of switching between different sinking modes, ensuring the control of key time when a variety of sinking modes are combined for construction, thereby ensuring the tightness and smoothness of the connection between the sinking stages, while also avoiding additional adjustment time and reducing the complexity of construction.

[0014] (3) The present invention can ensure the effectiveness and timeliness of sinking control by analyzing the changing law of the sinking rate and the stability of the sinking posture at each blade foot, and then setting various judgment conditions and performing sinking adjustment judgment, while also ensuring the sinking efficiency and the verticality and horizontality during the sinking process.

[0015] (4) When the cofferdam deflects, the present invention effectively avoids the shortcomings of a relatively single method in the subsequent sinking control process by linking multiple links of control, thereby more comprehensively and effectively dealing with various causes of deflection, thereby better achieving the correction effect, and at the same time greatly improving the construction efficiency and construction accuracy of the cofferdam. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for describing the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative work.

[0017] Figure 1 The figure is a schematic flow chart of the overall implementation steps of the method of the present invention.

[0018] Figure 2 S2 implementation step flow chart of the present invention.

[0019] Figure 3 Schematic diagram of the sinking adjustment judgment flow of the present invention. DETAILED DESCRIPTION

[0020] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0021] See also Figure 1 As shown, the present invention provides a method for controlling the sinking construction of a double-walled steel cofferdam without a bottom in deep-water bare rock geology, the method comprising: the method comprising: S1, data collection and preparation: collecting bare rock characteristic data and water body characteristic data in the construction area, and collecting information on the cofferdam, the information being size, shape, weight and surface roughness.

[0022] S2. Preliminary formulation of sinking plan: Based on the bare rock characteristic data, water body characteristic data and cofferdam information collected in step S1, confirm the switching point of the auxiliary sinking method and confirm the starting construction time period.

[0023] See also Figure 2 As shown, S3, sinking execution and adjustment confirmation: real-time monitoring of the status information during the sinking process, and making a sinking adjustment judgment. When the judgment result is adjustment, confirm the current adjustment sinking information. When the judgment result is no adjustment, continue to execute the sinking.

[0024] S4, sinking process control: Based on the current adjusted sinking information, the sinking construction process of the steel cofferdam is controlled. While implementing the control measures, return to step S3 until the cofferdam installation is completed.

[0025] Specifically, the data collected in step S1 can be imported by relevant personnel themselves.

[0026] Specifically, the bare rock characteristic data includes but is not limited to information about bare rock in the construction area, wherein the information about bare rock in the construction area includes the depth, shape, hardness of the maximum protrusion on the rock surface, and the length and width along the sinking direction of the cofferdam.

[0027] Specifically, the water body characteristic data includes, but is not limited to, the water flow velocity, maximum water level and water level difference in the construction water area during each monitoring period corresponding to each monitoring day, and the water flow velocity monitored at each current depth.

[0028] Specifically, regarding the confirmation of the switching of the auxiliary sinking mode in step S2, it includes: S21, extracting the water flow rate monitored at each current depth of the construction water area from the water characteristic data, and calculating the feasibility of the cofferdam's self-weight sinking at each depth based on the size and weight of the cofferdam.

[0029] S22. Extract the bare rock information in the construction area from the bare rock feature data, and then extract the depth, shape, hardness of the maximum bulge on the rock surface, and the length and width along the sinking direction of the cofferdam, to confirm the feasibility of the cofferdam's self-weight crossing at each calibrated monitoring bulge position.

[0030] S23, recording the depth where the self-weight sinking feasibility is less than 0 as the obstruction depth, and selecting the lowest obstruction depth from the obstruction depths.

[0031] S24. If the lowest obstruction depth is above the depth of the maximum protrusion on the rock surface, the lowest obstruction depth is used as the switching point for the auxiliary sinking mode.

[0032] S25. If the lowest obstruction depth is at or below the maximum convex depth of the rock surface, select the calibrated monitoring convex positions whose self-weight crossing feasibility is greater than or equal to 0, and use the calibrated monitoring convex position closest to the maximum convex depth of the rock surface as the auxiliary sinking mode switching point.

[0033] It should be added that when the steel cofferdam begins to sink by its own weight and then transitions to other auxiliary sinking methods such as high-pressure water jetting and air suction, if the switching timing cannot be accurately grasped, the auxiliary means may be used too early or too late. If the switch is too early, the cofferdam will be intervened when its own gravity still has enough margin to push it to continue sinking for a distance, which will not only waste resources, but also disturb the surrounding geology due to additional operations, bringing instability to the subsequent sinking. Switching too late may cause the cofferdam to stagnate due to excessive resistance, affecting the entire sinking progress and destroying the continuity of the sinking stage. At the same time, the timing of switching the sinking method is not right, resulting in unsatisfactory sinking of the steel cofferdam, and frequent situations requiring additional adjustments. For example, if a certain sinking method is used too early or too late, the cofferdam will tilt or deflect. At this time, it is necessary to suspend the sinking and use other correction methods to correct it. The correction process involves multiple links of operation and repeated monitoring, which undoubtedly greatly increases the construction time cost and makes the entire construction process more complicated and cumbersome, which is easy to cause delays and waste of resources.

[0034] It should also be added that the bulge of the rock surface is a major obstacle to the sinking of the cofferdam, especially when the cofferdam relies on its own weight to sink to the calibrated monitoring bulge position. If the sinking method is not switched in advance, it is likely that the blade foot will be stuck and the cofferdam posture will be unbalanced due to force problems at the bulge, and the blade foot will be stuck. The position where the self-weight crossing feasibility is greater than or equal to 0 is selected for sinking mode switching. Auxiliary sinking means such as high-pressure water jetting and air mud suction can be used to treat the bulge and its surrounding areas in advance. For example, high-pressure water jetting can be used to disperse the rocks at the bulge, reduce the friction between the blade foot and the rock, and use air mud suction to clean up the broken rocks and other debris that are washed up, so as to help the cofferdam cross the bulge more smoothly, avoid encountering serious obstacles at the bulge, resulting in stagnation of sinking or other construction difficulties. At the same time, switching the sinking method at the calibrated monitoring bulge position can adjust the force of the cofferdam in a targeted manner according to the specific conditions of the bulge, such as hardness, so that it is in a relatively favorable mechanical state when crossing the bulge. The auxiliary sinking method can reasonably distribute the relationship between the cofferdam gravity, water flow force and external force generated by the auxiliary sinking, reduce the resistance in the process of crossing the bulge, increase the effective sinking force, ensure that all parts of the cofferdam are evenly stressed when crossing the bulge, and prevent damage to the cofferdam structure due to excessive local force, thereby ensuring the smooth progress of the entire crossing process.

[0035] The embodiment of the present invention analyzes the feasibility of the cofferdam's self-weight sinking at various depths and the feasibility of its self-weight crossing at various calibrated monitoring raised positions to confirm the switching point of the auxiliary sinking mode, thereby effectively solving the current problem of insufficient attention to the timing of switching between different sinking modes, ensuring the control of key time during the construction of a combination of multiple sinking modes, thereby ensuring the tightness and smoothness of the connection between the sinking stages, while also avoiding additional adjustment time and reducing the complexity of construction.

[0036] Specifically, regarding the confirmation of the starting construction time period in step S2, it includes: Y1, extracting the water flow velocity, maximum water level height and water level height difference of the construction water area in each monitoring time period corresponding to each monitoring day from the water body characteristic data.

[0037] Y2. For the maximum water level, water flow rate and water level height difference in the construction water area on different monitoring days within the same monitoring period, standard deviation and mean calculation shall be performed respectively. The corresponding results shall be recorded as the difference in water level, the difference in water flow rate, the difference in water level height difference, the average water level, the average water flow rate and the average water level height difference.

[0038] Y3. Record the average water level and water level difference corresponding to each monitoring time period as relevant parameters, calculate the water level consistency of each monitoring time period through statistical formula, and calculate the water flow velocity consistency and water level difference consistency of each monitoring time period in the same way.

[0039] Y4. Set the weight coefficients of the above three kinds of consistency, and calculate the recommended construction degree of the comprehensive water status in each monitoring time period by weighted average.

[0040] Y5. Compare each monitoring time period with the preset suitable construction time period, record the time period within the suitable construction time period as an alternative time period, and take the alternative time period with the highest construction recommendation as the starting construction time period.

[0041] The embodiment of the present invention calculates the difference and mean of the water level height, water flow rate and water height difference in different monitoring time periods and different monitoring days, and then confirms the starting construction time period. It can fully grasp the hydrological characteristics and changes of the construction waters, thereby selecting the construction time when all conditions are relatively stable and conducive to the sinking construction of the double-walled steel cofferdam without a bottom in deep-water bare rock geology, laying a good foundation for the smooth progress of the entire construction process.

[0042] Further, it can be understood that, by calculating the difference in the water level height of the construction water area, the fluctuation of the water level within a specific monitoring period can be intuitively understood. A smaller difference means that the water level is relatively stable. For the sinking construction of double-walled steel cofferdams without bottom in deep-water bare rock geology, it is conducive to accurately controlling the sinking process of the steel cofferdam and ensuring construction safety, avoiding problems such as large changes in the buoyancy of the steel cofferdam and unstable relative position with surrounding fixtures due to large fluctuations in water levels. The difference in water flow velocity reflects the magnitude of the change in water flow velocity during the monitoring period. During the construction process, whether the water flow velocity is stable or not has an important influence on the impact force and directional stability of the steel cofferdam. A smaller flow velocity difference indicates that the water flow is relatively stable, which can reduce the deviation and shaking of the steel cofferdam caused by the impact of the water flow, and is conducive to the smooth construction according to the predetermined plan, especially in the key operations such as lowering and docking of the steel cofferdam. A stable water flow environment is very critical. The change in the water level height difference will affect the overall hydraulic conditions of the construction water area, and its difference reflects the degree of fluctuation of this difference on different monitoring days.

[0043] Furthermore, regarding the statistics performed through the statistical formula in step Y3, in order to maintain the consistency of subsequent calculation results, an exponential function can be selected at this time, and the function output result is limited to between 0 and 1. On the one hand, the consistency of the sign of the value result can be guaranteed, and on the other hand, the consistency of the value range can be guaranteed, thereby facilitating subsequent analysis.

[0044] Specifically, when using the exponential function to count the water level coincidence of each monitoring time period, the specific statistical process is as follows: the average water level and water level difference corresponding to each monitoring time period are recorded as and , Indicates the monitoring time period number. .

[0045] Statistical consistency of water level height in each monitoring period , and They are respectively the appropriate construction water level height and water level height difference for setting reference. is a natural constant.

[0046] For example, for the sinking construction of double-walled steel cofferdams without bottom in deep-water bare rock geology, if the design height, water entry depth and connection with subsequent construction procedures such as foundation construction of the steel cofferdam have specific requirements for the water level, then the appropriate water level range should be determined according to these structural dimensions and construction processes. For example, if the height of the steel cofferdam is 30 meters, the planned water entry depth is 20 meters, and it is hoped that a certain height such as 2-3 meters above the water surface is exposed at the top of the steel cofferdam for construction operations and monitoring, then the appropriate water level is roughly around 7-8 meters, and 8 meters can be selected as the appropriate construction water level for setting reference. Of course, the embodiments of the present invention are only examples, and can be adjusted accordingly according to engineering requirements.

[0047] As another example, in projects that require extremely high accuracy in sinking steel cofferdams, such as the construction of key foundation parts of some large cross-sea bridges, the water level height difference is expected to be controlled within 0.1-0.3 meters, and 0.3 meters can be selected specifically, so as to minimize the impact of water level fluctuations on the steel cofferdam, ensure that the construction can be carried out in accordance with precise design requirements, and avoid problems such as steel cofferdam tilt and position deviation caused by water level changes. For the construction of steel cofferdams in general parts of ordinary inland river bridges or water conservancy hubs, during the entire construction period, if the water level height difference can be guaranteed to be around 0.3-0.5 meters, and 0.5 meters can be selected specifically, it can usually meet the construction requirements. Of course, the embodiments of the present invention are only examples, and can be adjusted accordingly according to engineering requirements.

[0048] Furthermore, the weight coefficients of the above three degrees of consistency set in step Y4 are determined in a specific embodiment according to the specific characteristics of the project, the construction focus, and the sensitivity to various hydrological factors. The following are examples of values ​​in different situations: 1) Conventional construction scenario: The weight coefficients of the water level height consistency, the water flow velocity consistency, and the water level height difference consistency can be 0.35, 0.35, and 0.3, respectively.

[0049] 2) Engineering scenarios that are sensitive to water level fluctuations: If there are some existing hydraulic structures that are sensitive to water level changes around the construction area, or the design and construction technology of the steel cofferdam have high requirements on the stability of the water level height, the weight coefficients of the water level height consistency, water flow velocity consistency and water level height difference consistency can be taken as 0.5, 0.3 and 0.2 respectively.

[0050] 3) Construction scenarios where water flow impact force has a critical impact: If the water flow velocity in the construction water area is usually large, the water flow impact force plays a dominant role in the stability and posture control of the steel cofferdam during the sinking process. For example, in some projects in turbulent water areas such as narrow sections of rivers and estuaries, the weight coefficients of water level height consistency, water body flow velocity consistency and water level height difference consistency can be taken as 0.3, 0.5 and 0.2 respectively.

[0051] Furthermore, what needs to be added about step Y5 is that, according to the law of water flow velocity and water level changes, priority should be given to selecting periods with slow water flow and relatively stable water level for key sinking operations of the steel cofferdam, such as the initial lowering of the steel cofferdam and the precise sinking when approaching the design elevation. Avoid unfavorable periods such as flood seasons and high tides when the water flow is turbulent and the water level fluctuates greatly, thereby reducing the interference of water flow on the sinking of the steel cofferdam and safety risks.

[0052] Among them, in step S21, the feasibility of the cofferdam's self-weight sinking at each depth is calculated, including: J1, calculating its volume according to the size of the cofferdam, and calculating its regularity according to the shape of the cofferdam , the surface roughness of the cofferdam is .

[0053] J2. Water flow rate monitored at each depth , according to the fluid mechanics resistance formula, calculate the horizontal thrust of the water body on the cofferdam at each depth ,

[0054] , and are to set the reference regularity and surface roughness respectively, and denote the first drag coefficient and the second drag coefficient, respectively. It represents the projected area of ​​the cofferdam in the direction perpendicular to the water flow. represents the density of water, Indicates the depth number. , is a natural constant.

[0055] J3. Calculate the gravity based on the weight of the cofferdam , according to the size of the cofferdam, the buoyancy of the cofferdam at each depth is calculated using the Archimedes principle , and then calculate the expected inclination angle of the cofferdam at each depth through the mechanical balance formula .

[0056] J4. Statistical feasibility of the cofferdam sinking under its own weight at each depth ,

[0057] , represents the friction coefficient, is the effective sinking force for setting reference.

[0058] In a specific embodiment, the effective sinking force of the reference may be set to 10% of the deadweight of the cofferdam, that is, .

[0059] Understandably, The calculation result indicates the The effective sinking force at a depth is: effective sinking force = effective gravity - effective buoyancy - friction + the vertical component of the horizontal thrust of the water body on the cofferdam, and the effective weight and effective buoyancy are obtained by decomposing them according to the expected inclination angle.

[0060] Furthermore, it should be added about step J1 that when the cofferdam is a rectangle or a cylinder, the calculation is performed using the corresponding defined volume calculation formula; when the cofferdam is irregular, it can be divided into multiple regular-shaped parts by the segmentation method, and the corresponding calculation is performed according to the regular-shaped relevant volume calculation formula, and the sum of the volumes of the multiple regular-shaped parts is used as the volume of the cofferdam.

[0061] It should be added that the specific calculation of the regularity of the cofferdam according to its shape is as follows: J11. Based on the shape of the cofferdam, the cofferdam is cut to obtain each cut cofferdam part, and the outline of each cut cofferdam part is extracted.

[0062] J12. Randomly select a cutting cofferdam part as the reference part, and compare and overlap the outline of the reference part with the outlines of other cutting cofferdam parts to obtain the overlapping volume of the outlines of the reference part and other cutting cofferdam parts, and divide it by the overlapping volume of the outlines of the reference part. The ratio is recorded as the overlapping contour volume ratio.

[0063] J13. Repeat the above steps to obtain the overlapping contour volume ratio between each cutting cofferdam part in turn, and take the cutting cofferdam part with the overlapping contour volume ratio greater than the set value as the similar part of the corresponding cutting cofferdam part, count the number of similar parts of each cutting cofferdam part, and filter out the maximum value from them. ,Will As a similarity ratio, Indicates the number of cut cofferdam sections.

[0064] J14. Calculate the standard deviation of the overlapping contour volume ratio between each cutting cofferdam part to obtain the overlapping contour volume ratio difference ,Will As the regularity of the cofferdam.

[0065] Furthermore, the resistance coefficient in step J2 is generally obtained through experiments or experience, and the common value is between 0.15 and 1.5, that is, and The values ​​are 0.15 and 1.5 respectively.

[0066] It is understandable that the drag coefficient is related to the shape and surface roughness of the cofferdam, so the shape of the cofferdam is used to calculate the regularity, and the correction factor is set based on the two indicators of regularity and surface roughness. represents a correction factor, ranging from 0 to 1, and exemplarily, The value can be 0.5. The value can be 12.5 microns.

[0067] In one embodiment, fresh water The value is ,seawater The value is .

[0068] Furthermore, regarding the buoyancy of the cofferdam at each depth in step J3 = the drainage volume at each depth × the density of water × the gravity coefficient.

[0069] It should be added that the supplementary calculation of the expected inclination angle of the cofferdam at each depth calculated by the mechanical balance formula is as follows: When the cofferdam is subjected to horizontal thrust at a certain depth, it will tilt, and the inclination angle is recorded as , the horizontal thrust can be decomposed into vertical and horizontal components, and the horizontal thrust corresponding to the depth is recorded as ,Will Marked as the component of horizontal thrust in the vertical direction, The component of horizontal thrust in the horizontal direction is marked as follows: , At the same time, the positive pressure between the bottom of the cofferdam and the contact surface of the water bottom will also change, positive pressure is the component of gravity perpendicular to the bottom surface The resultant force of the horizontal thrust and the vertical component of the horizontal thrust The sum of .

[0070] In the tilted state, the equation is established based on the force balance parallel to the bottom surface and other conditions:

[0071] ,Right now .

[0072] In a specific embodiment, the starting time period has been selected before the cofferdam sinks, that is, the water flow rate will affect the sinking of the cofferdam, but the effect will not be very significant, that is, a weak effect, and the interference caused by the horizontal thrust will also be lower than the deadweight, and the inclination angle of the cofferdam will also be smaller. For example, The value is 0.4.

[0073] Among them, step S23 confirms the feasibility of the cofferdam's self-weight crossing at each calibrated monitoring convex position, including: R1, the length of the maximum convexity of the rock surface along the sinking direction of the cofferdam is , the width perpendicular to the sinking direction is .

[0074] R2. For each calibrated monitoring raised position, first obtain its depth value, and then calculate the water pressure at each calibrated monitoring raised position according to the water pressure calculation formula , Indicates the number of the calibrated monitoring raised position. .

[0075] R3. Calculate the effective force component of the cofferdam in the vertical direction of gravity at each calibrated monitoring convex position. , and use the friction calculation formula to calculate the friction force of the cofferdam at each calibrated monitoring convex position , and confirm the additional resistance of the rock surface, recorded as .

[0076] R4. Calculate the feasibility of the cofferdam’s self-weight span at each calibrated monitoring bulge ,

[0077] .

[0078] It should be added that the gravity of the cofferdam at the calibrated monitoring convex position can be decomposed into a component perpendicular to the convex slope and a component parallel to the convex slope. According to the trigonometric function relationship , can be obtained

[0079] , . and Respectively represent the cofferdam in the The gravity at the calibrated monitoring bulge position is decomposed into the component of force perpendicular to the bulge slope surface and the component of force parallel to the bulge slope surface.

[0080] It should be added that the index of the feasibility of self-weight crossing is expressed by the ratio of the difference between the component of gravity along the slope direction minus the friction force and the additional resistance to the component of gravity along the slope direction. Indicates that the cofferdam is The component of gravity along the slope direction corresponding to the calibrated monitoring convex position.

[0081] Further, the calculation formula for the water pressure at each calibrated monitoring protrusion position in step R2 is as follows: , Indicates The depth value of the calibrated monitoring convex position, Represents the acceleration due to gravity.

[0082] Furthermore, regarding the calculation of the effective component of the cofferdam in the vertical direction of gravity at each calibrated monitoring convex position in step R3, , , Indicates that the cofferdam is The displacement volume at a calibrated monitoring bulge location.

[0083] Understandably, the cofferdam The drainage volume at the calibrated monitoring convex position can be determined by combining the cofferdam in the The calculation is performed based on the posture at the calibrated monitoring bulge position, wherein the calculation method of the drainage volume is a relatively mature existing calculation method and will not be demonstrated here.

[0084] Furthermore, the calculation formula for the friction force of the cofferdam at each calibrated monitoring convex position in step R3 is: , Represents the friction coefficient between the blade foot and the bare rock.

[0085] It should be added that the friction coefficient between the blade foot and the bare rock is obtained through field tests or reference to similar engineering experience.

[0086] Furthermore, the additional resistance of the rock surface in step R3 is determined by drawing a three-dimensional contour according to the shape of the largest protrusion on the rock surface, and calculating the ratio of the volume of the three-dimensional contour to the volume of the smallest external sphere, which is recorded as .

[0087] The hardness of the largest convex part of the rock surface is , calculate the additional resistance of the rock surface ,

[0088] , To set the reference baseline additional resistance, and are the volume ratio and rock hardness of the reference respectively.

[0089] Understandably, ,

[0090] Indicates the compensation factor for the resistance setting at the maximum protrusion of the rock surface.

[0091] In a specific embodiment, The value can be 0.7. The hardness is expressed by the Proctor coefficient, and the specific value can be 2. It is set with reference to the Proctor coefficient of medium-hard rock. For the sinking of the cofferdam, the medium-hard rock will produce a certain resistance. For soft rock, the main consideration may be to prevent sinking too fast and keep the cofferdam posture stable.

[0092] Specifically, see Figure 3 As shown, the sinking adjustment judgment in step S3 includes: S31, extracting the horizontal displacement value and the vertical displacement value of each blade foot from the real-time monitoring sinking state information.

[0093] S32, integrating the blades on the same cofferdam side, and calculating the standard deviation of the vertical displacement value and the horizontal displacement value at each blade on the same cofferdam side at the current time point, and obtaining the vertical deviation and horizontal deviation of each cofferdam side, which are recorded as and , Indicates the cofferdam side number, .

[0094] S33, filter out the maximum value of the horizontal displacement value and the vertical displacement value at each blade foot of the same cofferdam side at the current time point, obtain the maximum horizontal displacement value and the maximum vertical displacement value of each cofferdam side, and record them as and ;

[0095] S34. Calculate the standard deviation of the maximum horizontal displacement and maximum vertical displacement on different cofferdam sides to obtain the overall horizontal deviation Deviation from overall vertical displacement .

[0096] S35. Calculate the stability of the sinking posture of the cofferdam ,

[0097] , , and They are used to set the reference vertical deviation, horizontal deviation and horizontal displacement values ​​respectively.

[0098] S36, extracting the sinking speed of each blade foot from the real-time monitoring sinking status information, and defining various conditions, including condition 1, condition 2 and condition 3.

[0099] S37. Determine whether any of the conditions are met. If so, make adjustments as the determination result. If not, make no adjustments as the determination result.

[0100] The embodiment of the present invention can ensure the effectiveness and timeliness of the sinking control by analyzing the changing law of the sinking rate and the smoothness of the sinking posture at each blade foot, and then setting various judgment conditions and performing sinking adjustment judgment, while also ensuring the sinking efficiency and the verticality and horizontality during the sinking process.

[0101] Furthermore, various conditions are defined in step S36, including: constructing a sinking speed change curve at each blade foot with time as the horizontal coordinate and the sinking speed as the vertical coordinate, extracting the slope of the curve as the sinking speed change rate, and screening out its maximum and minimum values ​​to form a sinking rate change range.

[0102] The standard deviation of the change rate of the sinking velocity at each blade foot is calculated to obtain the difference in the change of the sinking velocity at the blade foot.

[0103] The difference in the change of the sinking speed at the blade foot is greater than or equal to the set value as condition 1, the part of the sinking rate change range that is outside the set reference sinking rate change range is defined as condition 2, and the sinking posture smoothness is less than the set reference sinking posture smoothness is defined as condition 3.

[0104] In a specific embodiment, the vertical deviation and horizontal deviation of the reference may be set to 10 mm, and the horizontal displacement value of the reference may be set to 20 mm.

[0105] In another specific embodiment, confirming the current adjustment of the sinking information includes: E1. If condition 1 or condition 2 is met, setting the sinking speed adjustment as the adjustment item; if condition 3 is met, setting the sinking posture adjustment as the adjustment item.

[0106] E2. If the adjustment item is the sinking speed and condition 1 is met, the current sinking depth is extracted from the real-time monitoring sinking status information, and matched and compared with the reference sinking depths corresponding to the set reference sinking speed ranges to obtain the matching reference sinking speed range.

[0107] E3. Calculate the reference speed difference for each blade foot, average the reference speed differences of each blade foot on the same cofferdam side, and obtain the comprehensive speed difference on each cofferdam side. , count the adjustment tension of the corresponding suspension ropes on each cofferdam side , , is the proportionality coefficient, as an adjustment indicator.

[0108] E4. If the adjustment item is sinking speed and meets condition 2, when the lower limit of the sinking rate change interval is less than the lower limit of the sinking rate change interval set as the reference, the difference between the two is calculated and recorded as the sinking rate difference. When the current mode is the self-weight sinking mode, the current sinking depth is used as the auxiliary sinking mode switching point and as the adjustment index. When the current mode is not the self-weight sinking mode, the sinking rate difference is matched and compared with the sinking rate difference interval corresponding to the set adjustment drainage ratio, and the matched adjustment drainage ratio is used as the adjustment index.

[0109] E5. When the upper limit of the sinking rate change interval is greater than the upper limit of the sinking rate change interval set as the reference, as an adjustment indicator.

[0110] E6. If the adjustment item is an adjustment posture, confirm the adjustment index, and then use the adjustment item and the adjustment index under the adjustment item as the current adjustment sinking information.

[0111] Further, confirming the adjustment index includes: extracting the current tilt angle from the real-time monitoring sinking status information and tilt direction.

[0112] Calculate the volume of injected water , , Indicates the arm length from the water injection position to the cofferdam rotation axis, Indicates the center of gravity height of the cofferdam.

[0113] The direction of the inclination is taken as the water injection direction, and the water injection direction, the injected water volume and the adjustment tension of the corresponding associated hanging gods on each cofferdam side are taken as adjustment indicators.

[0114] It should be added that when the cofferdam is tilted, water is added or drained into different compartments of the cofferdam to change its weight distribution, and then the moment generated by gravity is used to restore the cofferdam to a vertical state. The core is to calculate the amount of water that needs to be adjusted and the corresponding compartment operation based on the moment balance principle.

[0115] In a specific embodiment, when the cofferdam is a rectangular parallelepiped, assuming that its mass is evenly distributed, its center of gravity is at the geometric center position, and the center of gravity height is half of its height. For the cofferdam in the shape of a cylinder, also under the assumption of uniform mass distribution, its center of gravity is located at the midpoint of the central axis of the cylinder, and the center of gravity height is also half of its height. If the cofferdam is composed of multiple simple shapes, the cofferdam can be divided into multiple parts of known shapes, and the volume and center of gravity position coordinates of each part are calculated separately, and the center of gravity height is calculated according to the center of gravity calculation formula, where the center of gravity calculation formula is an existing formula and is not used as an example here.

[0116] In another specific embodiment, for a rectangular cofferdam, it can usually be rotated around a certain bottom side. For example, when the short side is inclined, the straight line where the short side is located can be regarded as the rotation axis. If the coordinates of the center position of the water-filled chamber are , , a circular cofferdam can generally use the vertical axis where the center of the circle is located as the reference axis of rotation. Assuming that the cofferdam is twisted and tilted around the axis, if the angle between the radius direction corresponding to the location of the water-filled compartment and a certain reference radius direction is known , and the distance between the cabin and the center of the circle is , .

[0117] It should be noted that in practice, the cabins of the circular cofferdam may not be evenly distributed at equal angles, or there may be complex situations such as multi-layer cabin structures. At this time, it is also necessary to follow the detailed design drawings. For irregular-shaped cabins, first determine the center of gravity of the water-filled cabin. For regular-shaped cabins, determine the geometric center position, and then calculate the lever arm length by geometric methods. When the rectangle is irregular, measure the vertical distance from the center position to the selected rotation axis. This vertical distance is the required lever arm length. At the same time, it is necessary to consider the change in the position relationship of the cabin relative to the rotation axis after the cofferdam is tilted. Generally, the lever arm length is determined by the structural design in the initial non-tilted state.

[0118] The embodiment of the present invention realizes multi-link control by linking water injection information and adjusting tension when the cofferdam is skewed, effectively avoiding the deficiency of a relatively single method in the subsequent sinking control process, thereby more comprehensively and effectively dealing with various causes of deflection, thereby better achieving the correction effect, and at the same time greatly improving the construction efficiency and construction accuracy of the cofferdam, and also ensuring the stability and effectiveness of sinking speed control.

[0119] The above contents are merely examples and explanations of the concept of the present invention. Those skilled in the art may make various modifications or additions to the specific embodiments described or replace them in a similar manner. As long as they do not deviate from the concept of the invention or exceed the scope defined by the present invention, they shall all fall within the protection scope of the present invention.

Claims

1. A method for controlling the sinking construction of a double-walled steel cofferdam without a bottom seal in deep-water bare rock geology, characterized in that: The method includes: S1. Data collection and preparation: Collect the bare rock characteristic data and water characteristic data of the construction area, and collect the information of the cofferdam, including size, shape, weight and surface roughness; S2. Preliminary formulation of sinking plan: Based on the bare rock characteristic data, water body characteristic data and cofferdam information collected in step S1, confirm the switching point of the auxiliary sinking method and confirm the starting construction time period; The step of confirming the switching of the auxiliary sinking mode includes: Extract the water flow rate monitored at various depths in the construction water area from the water body characteristic data, and calculate the feasibility of the cofferdam's self-weight sinking at various depths based on the size and weight of the cofferdam; Extract the information of bare rock in the construction area from the bare rock feature data, and then extract the depth, shape, hardness of the maximum bulge on the rock surface, and the length and width along the sinking direction of the cofferdam, and confirm the feasibility of the cofferdam's self-weight crossing at each calibrated monitoring bulge position; The depth where the feasibility of self-weight sinking is less than 0 is recorded as the obstruction depth, and the lowest obstruction depth is selected from various obstruction depths; If the lowest obstruction depth is above the depth of the maximum bulge on the rock surface, the lowest obstruction depth is used as the switching point for the auxiliary sinking mode; If the lowest obstruction depth is at or below the maximum convex depth of the rock surface, select the calibrated monitoring convex positions with self-weight crossing feasibility greater than or equal to 0, and use the calibrated monitoring convex position closest to the maximum convex depth of the rock surface as the auxiliary sinking mode switching point; S3, sinking execution and adjustment confirmation: real-time monitoring of the status information during the sinking process, and making a judgment on the sinking adjustment. When the judgment result is adjustment, confirm the current adjustment sinking information. When the judgment result is no adjustment, continue to execute the sinking; S4, sinking process control: Based on the current adjusted sinking information, the sinking construction process of the steel cofferdam is controlled. While implementing the control measures, return to step S3 until the cofferdam installation is completed.

2. A method for controlling the sinking construction of a deepwater bare rock geological double-walled steel cofferdam without a bottom seal as claimed in claim 1, characterized in that: The confirmation of the starting construction time period includes: Extract the water flow velocity, maximum water level and water level height difference in the construction water area in each monitoring period on each monitoring day from the water body characteristic data; For the maximum water level, water flow rate, and water level height difference in the construction water area on different monitoring days within the same monitoring period, standard deviation and mean calculation are performed respectively, and the corresponding results are recorded as the difference of water level height, the difference of water flow rate, the difference of water level height difference, the average water level, the average water flow rate, and the average water level height difference; The average water level and water level difference corresponding to each monitoring time period are recorded as relevant parameters, and the water level consistency of each monitoring time period is calculated by statistical formula, and the water flow velocity consistency and water level difference consistency of each monitoring time period are calculated in the same way; Set the weight coefficients of the above three kinds of consistency, and calculate the recommended construction degree of the comprehensive water status in each monitoring period by weighted average; Compare each monitoring time period with the preset suitable construction time period, record the time period within the suitable construction time period as an alternative time period, and take the alternative time period with the highest construction recommendation as the starting construction time period.

3. A method for controlling the sinking construction of a deepwater bare rock geological double-walled steel cofferdam without a bottom seal as claimed in claim 1, characterized in that: The feasibility of calculating the self-weight sinking of the cofferdam at each depth includes: Calculate the volume based on the size of the cofferdam and the regularity based on the shape of the cofferdam. , the surface roughness of the cofferdam is ; The water flow rate monitored at each depth , according to the fluid mechanics resistance formula, calculate the horizontal thrust of the water body on the cofferdam at each depth , , and are to set the reference regularity and surface roughness respectively, and denote the first drag coefficient and the second drag coefficient, respectively. It represents the projected area of ​​the cofferdam in the direction perpendicular to the water flow. represents the density of water, Indicates the depth number. , is a natural constant; Calculate the gravity based on the weight of the cofferdam , according to the size of the cofferdam, the buoyancy of the cofferdam at each depth is calculated using the Archimedes principle , and then calculate the expected inclination angle of the cofferdam at each depth through the mechanical balance formula ; Statistical feasibility of cofferdam sinking under its own weight at various depths , , represents the friction coefficient, is the effective sinking force for setting reference.

4. A method for controlling the sinking construction of a deepwater bare rock geological double-walled steel cofferdam without a bottom seal as claimed in claim 1, characterized in that: The confirmation of the feasibility of the deadweight crossing of the cofferdam at each calibrated monitoring convex position includes: The length of the maximum bulge of the rock surface along the sinking direction of the cofferdam is , the width perpendicular to the sinking direction is ; For each calibrated monitoring raised position, first obtain its depth value, and then calculate the water pressure at each calibrated monitoring raised position according to the water pressure calculation formula , Indicates the number of the calibrated monitoring raised position. ; Calculate the effective force component of the cofferdam in the vertical direction of gravity at each calibrated monitoring convex position , and use the friction calculation formula to calculate the friction force of the cofferdam at each calibrated monitoring convex position , and confirm the additional resistance of the rock surface, recorded as ; Calculate the feasibility of the cofferdam's deadweight span at each calibrated monitoring bulge , 。 5. A method for controlling the sinking construction of a double-walled steel cofferdam without a bottom seal in deep-water bare rock geology as claimed in claim 4, characterized in that: The additional resistance of the rock surface is confirmed, including: Draw the three-dimensional contour according to the shape of the largest convex part of the rock surface, and calculate the ratio of the volume of the three-dimensional contour to the volume of the smallest external sphere, which is recorded as ; The hardness of the largest convex part of the rock surface is , calculate the additional resistance of the rock surface , , To set the reference baseline additional resistance, and are the volume ratio and rock hardness of the reference respectively.

6. A method for controlling the sinking construction of a double-walled steel cofferdam without a bottom in deep-water bare rock geology as claimed in claim 3, characterized in that: The sinking adjustment judgment comprises: Extract the horizontal displacement value and vertical displacement value of each blade foot from the real-time monitoring sinking status information; Integrate the blades on the same cofferdam side, calculate the standard deviation of the vertical displacement value and horizontal displacement value of each blade at the same cofferdam side at the current time point, and obtain the vertical deviation and horizontal deviation of each cofferdam side, which are recorded as and , Indicates the cofferdam side number, ; The maximum value of the horizontal displacement value and the vertical displacement value at each blade foot of the same cofferdam side at the current time point is selected to obtain the maximum horizontal displacement value and the maximum vertical displacement value of each cofferdam side, and they are recorded as and ; The standard deviation of the maximum horizontal displacement and maximum vertical displacement on different cofferdam sides was calculated to obtain the overall horizontal deviation. Deviation from the overall vertical displacement ; Calculate the stability of the sinking posture of the cofferdam , , , and They are respectively used to set the vertical deviation, horizontal deviation and horizontal displacement value of the reference; Extract the sinking speed of each blade foot from the real-time monitoring sinking status information, and define various conditions, including condition 1, condition 2 and condition 3; Determine whether any of the conditions are met. If so, make adjustments as the judgment result. If not, make no adjustments as the judgment result.

7. A method for controlling the sinking construction of a double-walled steel cofferdam without a bottom in deep-water bare rock geology as claimed in claim 6, characterized in that: The conditions described herein include: The sinking velocity variation curves at each blade foot were constructed with time as the horizontal coordinate and sinking velocity as the vertical coordinate. The slope of the curve was extracted as the sinking velocity variation rate, and its maximum and minimum values ​​were screened out to form the sinking velocity variation interval. The standard deviation of the change rate of the sinking velocity at each blade foot is calculated to obtain the difference in the change of the sinking velocity at the blade foot; The difference in the change of the sinking speed at the blade foot is greater than or equal to the set value as condition 1, the part of the sinking rate change range that is outside the set reference sinking rate change range is defined as condition 2, and the sinking posture smoothness is less than the set reference sinking posture smoothness is defined as condition 3.

8. A method for controlling the sinking construction of a double-walled steel cofferdam without a bottom seal in deep-water bare rock geology as claimed in claim 7, characterized in that: The confirmation of the current adjustment sinking information includes: If condition 1 or condition 2 is met, the sinking speed adjustment is set as the adjustment item, and if condition 3 is met, the sinking attitude adjustment is set as the adjustment item; If the adjustment item is the sinking speed and condition 1 is met, the current sinking depth is extracted from the real-time monitoring sinking state information, and matched and compared with the reference sinking depths corresponding to the set reference sinking speed ranges to obtain the matching reference sinking speed range; Calculate the reference speed difference for each blade foot, average the reference speed differences of each blade foot on the same cofferdam side, and obtain the comprehensive speed difference on each cofferdam side. , count the adjustment tension of the corresponding suspension ropes on each cofferdam side , , is the proportionality coefficient, As an adjustment indicator; If the adjustment item is the sinking speed and condition 2 is met, when the lower limit of the sinking rate change interval is less than the lower limit of the sinking rate change interval set as the reference, the difference between the two is calculated and recorded as the sinking rate difference. When the current sinking mode is the self-weight sinking mode, the current sinking depth is used as the auxiliary sinking mode switching point and as the adjustment index. When the current sinking mode is not the self-weight sinking mode, the sinking rate difference is matched and compared with the sinking rate difference interval corresponding to each set adjustment drainage ratio, and the matched adjustment drainage ratio is used as the adjustment index; When the upper limit of the sinking rate change interval is greater than the upper limit of the sinking rate change interval set as the reference, As an adjustment indicator; If the adjustment item is an adjustment posture, confirm the adjustment indicator, and then use the adjustment item and the adjustment indicator under the adjustment item as the current adjustment sinking information.

9. A method for controlling the sinking construction of a double-walled steel cofferdam without a bottom seal in deep-water bare rock geology as claimed in claim 8, characterized in that: The confirmation adjustment indicators include: Extracting the current tilt angle from real-time monitoring sinking status information and tilt direction; Calculate the volume of injected water , , Indicates the arm length from the water injection position to the cofferdam rotation axis, represents the height of the center of gravity of the cofferdam, represents the acceleration due to gravity; The direction of the inclination is taken as the water injection direction, and the water injection direction, the injected water volume and the adjustment tension of the corresponding associated hanging gods on each cofferdam side are taken as adjustment indicators.

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