Special-shaped reinforcement cage lowering and deviation rectifying method

Abstract

The invention discloses a special-shaped reinforcement cage lowering and deviation rectifying method which is characterized in that multi-modal modeling is adopted to obtain different depth structures of a groove body, and then a sensor assembly is used for detecting the depth and posture of a reinforcement cage. The posture of the reinforcement cage is adjusted by comparing the deviation between the current posture vector of the reinforcement cage and the axis of a tank body which is about to arrive, lowering of the reinforcement cage is completed, and the method specifically comprises the steps of system building, tank body model building, reinforcement cage posture determining, reinforcement cage closing external force vector obtaining, reinforcement cage lowering and reinforcement cage butt joint. And the reinforcement cage is completely lowered. According to the method, the pose of the reinforcement cage is monitored in real time, the axis of the groove body is accurately matched through the B spline curve, then the stress of the lifting point is dynamically adjusted, real-time deviation correction and feedback are achieved, and compared with traditional manual lifting and judgment, the real-time position and state of the reinforcement cage can be checked, and the problem of clamping stagnation of the reinforcement cage can be fundamentally solved.

Description

Technical Field

[0001] The present invention relates to the technical field of geological infrastructure, in particular to a construction process method for lowering a steel cage before pouring an anti-seepage wall, and specifically to a method for lowering and correcting a special-shaped steel cage. Background Art

[0002] The main methods for lowering the steel cage in the construction of geological anti-seepage walls are the segmented hoisting method, the integral hoisting method, and the synchronous lowering process combined with the continuous pouring of slots. The segmented hoisting method decomposes the steel cage into several segments, lowers them into the slots one by one using a crane, and achieves overall splicing through welding or mechanical connection. It is suitable for projects with large depths or complex geological conditions, but there are problems such as unstable connection quality and long time consumption. The integral hoisting method uses large lifting equipment to lower the complete steel cage at one time. It is more efficient, but has strict requirements on the verticality of the slot, the stability of the slot wall, and the lifting capacity of the equipment. It is easy to fail to lower the steel cage due to local collapse of the slot or deformation of the steel cage by its own weight. In addition, some projects use guide frames or temporary support structures to assist in positioning, or combine with the simultaneous pouring of concrete pipes to balance the pressure in the slot, but it is necessary to coordinate the lowering speed with the pouring progress, which is difficult to operate. The main problems currently faced are concentrated in three aspects: First, the structural strength of the steel cage itself is insufficiently compatible with the slot environment. Especially in deep trenches, soft soil layers, or conditions with high seepage pressure, the steel cage is easily affected by lateral soil pressure, fluid buoyancy, and pouring impact, causing distortion, displacement, or floating. Second, the stability of the slot is difficult to control. The effectiveness of the mud wall is affected by factors such as stratum permeability and groundwater flow rate, which can easily cause the hole to collapse or sediment accumulation, resulting in the steel cage being stuck or vertical deviation. Third, the contradiction between construction precision and efficiency is prominent. Although the segmented connection process can adapt to complex working conditions, welding quality inspection is difficult and the process connection is time-consuming. When lowering the steel cage into deep strata, the lack of precise control leads to interference with the slot body, resulting in the collapse of the slot sidewalls. Damage remains a prominent technical problem. The overall hoisting system is highly dependent on equipment, which limits its applicability in narrow sites or complex geological conditions. At the same time, monitoring technology is relatively lagging, lacking dynamic feedback on the real-time posture and stress state of the steel cage, making it difficult to accurately control the lowering process. These technical bottlenecks restrict the further improvement of the integrity and anti-seepage performance of the anti-seepage wall structure, and urgently need to be broken through by optimizing cage design, developing intelligent control systems and innovating flexible connection processes. Summary of the Invention

[0003] In order to solve the problem that the steel cage cannot be accurately adjusted during the lowering process, resulting in the deflection of the steel cage, which easily causes the steel cage to damage the side wall of the trough, thereby causing the steel cage to be stuck and the side wall of the trough to collapse, the present invention provides a method for lowering and correcting a special-shaped steel cage. By detecting the working condition of the trough in advance and establishing a three-dimensional model of the trough, the direction of the axis of the trough at different depths is fully understood; then during the lowering process of the steel cage, the state of the steel cage is detected in real time, including position, posture, deflection, etc., the direction of the axis of the steel cage is understood, and by comparing the axis deviation of the steel cage and the trough, the torque required to correct the deflection of the steel cage is obtained to correct the steel cage until the steel cage coincides with or is close to the axis of the stratum to be reached. Then, the steel cage is continued to be lowered, which can effectively solve the problem that the steel cage interferes with the side wall of the trough due to deflection, damages the retaining wall, and even causes the collapse of the trough.

[0004] In order to achieve the above objectives, the technical solutions adopted in this application are:

[0005] A method for lowering and correcting a special-shaped steel cage adopts multimodal modeling to obtain the structure of different depths of the trough body. A sensor component is then used to detect the depth and posture of the steel cage. The posture of the steel cage is adjusted by comparing the deviation between the current posture vector of the steel cage and the trough body axis to be reached, and the steel cage is lowered. The method specifically includes the following steps:

[0006] Step STP100: System setup: A fixed sonar and a mobile electromagnetic wave profiler are respectively arranged at the slot of the tank body where the steel cage is to be lowered. The fixed sonar includes four fixed sonar probes installed in a cross shape on the edge of the tank body side wall. The electromagnetic wave profiler's movement trajectory covers the central axis of the slot;

[0007] Step STP200: Establish a tank model. Use a tank scanning unit including a fixed sonar and a mobile electromagnetic wave profiler to scan the tank. Then, fuse the acquired sonar data and electromagnetic wave data to establish a spatial coordinate system W with the fixed sonar as the origin, and form a three-dimensional point cloud model of the tank S(z)={(x i ,y i ,z i )|i=1,2,3,…n}, complete the three-dimensional model construction;

[0008] Step STP300: tank axis fitting, using improved B-spline curve to fit the longitudinal axis C(z) of the tank model.

[0009]

[0010] Among them, N i,p is the p-order B-spline basis function, Q i are the coordinates of the control points;

[0011] Step STP300: Determine the posture of the rebar cage. Use a lifting device and a point-correction mechanism to vertically lift the first section of the rebar cage. The line connecting the lifting device and the connection point at the top of the first section of the rebar cage is rectangular. The bottom of the first section of the rebar cage is equipped with a well radar and a downward-mounted sonar connected to the control center, as well as INS modules installed at the top and bottom of the rebar cage, and an inclination sensor array installed along the length of the rebar cage. The current real-time posture vector of the rebar cage is obtained through the INS module and the inclination sensor array.

[0012]

[0013] Among them, X, Y, Z are the center point O of the bottom of the current steel cage B In the spatial coordinate system W, α, β, and γ are the yaw angle, pitch angle, and roll angle of the reinforcement cage axis, respectively;

[0014] Step STP400, obtain the external force vector of the steel cage, and obtain the external force vector F of the steel cage by establishing a dynamic model of the steel cage under mud ext ,

[0015]

[0016] Among them, M represents the mass matrix of the steel cage, C represents the damping matrix, and K represents the stiffness matrix;

[0017] Step STP500, the steel cage is lowered, and the real-time posture vector of the current tank axis and the steel cage is compared. Calculate the torque M required for correction correct ,

[0018]

[0019] Among them, F i is the tension at each lifting point of the steel cage, r i is the position vector of each hanging point;

[0020] The control center first sends a correction signal to the point correction mechanism, and then sends a lowering command to the lifting device after the correction is completed, until the current trough axis and the real-time posture vector of the steel cage are aligned. When the deviation between the two reaches the system preset correction value, the lifting device is suspended and the correction of this step is repeated until the top of the current steel cage exceeds the ground height by 1m.

[0021] In step STP600, the steel cages are docked and fixed using a ground fixing device. The point-correction mechanism is released, and another section of the steel cage is lifted and fixed to the current one. The ground fixing device is then released and step STP500 is executed until the steel cage touches the bottom of the trough, completing the lowering of the steel cage.

[0022] Preferably, in order to reduce the problem of decreased accuracy of the tank body three-dimensional point cloud model S(z) caused by data acquisition distortion due to errors, the step of optimizing the tank body three-dimensional point cloud model S(z) in step STP200 is further included. Specifically, the RANSAC algorithm is used to remove abnormal points using the following expression:

[0023]

[0024] Here, ρ(·) represents the robust loss function, and a, b, c, and d represent the coefficients of the plane equation in three-dimensional space.

[0025] The present invention also provides another method for fitting the tank axis after removing abnormal points based on the RANSAC algorithm. Specifically, the tank axis fitting step in step STP300 is replaced with the following steps:

[0026] Step STP310: Establish the coordinates of the axis point at any depth in the X-axis direction and the Y-axis direction respectively:

[0027] x=f(z)=a0+a1z+a2z 2

[0028] y=g(z)=b0+b1z+b2z 2

[0029] Where a0, b0 represent the initial offset of the axis at the notch z = 0; a1, b1 represent the linear slope of the axis with depth; a2, b2 represent the curvature of the axis, which is used to reflect the degree of axis bending;

[0030] Step STP320, the 3D point cloud of the tank after elimination by RANSAC algorithm {(x i ,y i ,z i )}Use the least squares method to construct the matrix equation:

[0031] By solving the matrix inversion or QR decomposition, the coefficients a0, a1, a2 and b0, b1, b2 can be obtained, thereby solving the coordinates of the axis point at any depth.

[0032] In order to further reduce the problem of the steel cage getting stuck during the lowering process due to the low verticality of the trough or the tilt of the steel cage itself, preferably, an annular guide wheel group is installed on each section of the steel cage side wall along the length of the steel cage, and the axial distance between two adjacent guide wheels is 5-15m. The annular guide wheels are located on the outside of the steel cage, contacting the side wall of the trough before the steel cage, and are arranged along the length. Regardless of the length of the steel cage, they can effectively provide auxiliary support and reduce the pressure of correction. Under the premise of adding the annular guide wheel group, even if the steel cage is close to the side wall of the trough or the axis of the trough is not straight and there is a bend, and it is inevitable that the deep bottom steel cage will contact the trough during the lowering process, it can still effectively reduce the friction resistance between the steel cage and the side wall of the trough, which is conducive to the normal lowering of the steel cage.

[0033] During the lowering process, the part of the rebar cage most likely to interfere with the trough is the bottom. Because the rebar cage itself lacks guidance, if it deflects within the trough, the bottom of the rebar cage can easily get stuck in the trough sidewalls, causing collapse. Simultaneously, the rebar cage can get stuck in the trough. To address this issue, the present invention employs a flexible hinged structure at the bottom of the rebar cage. The hinged structure is a deformable structure with its own guidance, hinged to the bottom of the rebar cage. This hinged structure allows the bottom of the rebar cage to be hinged to a guide structure that can deflect within a certain range. The sidewalls and bottom of the guide structure utilize smooth curved surfaces to achieve interference guidance, preventing the rebar cage from getting stuck in the trough sidewalls.

[0034] In order to facilitate control and reduce the amount of correction calculation, preferably, the point correction mechanism includes 4 sets of independent servo hoisting mechanisms or 4 hydraulic cylinders installed on the same rigid platform.

[0035] Beneficial effects:

[0036] 1. The present invention monitors the position of the steel cage in real time, accurately matches the trough axis through the B-spline curve, and then dynamically adjusts the force of the lifting point to achieve real-time correction and feedback. Compared with traditional manual lifting and judgment, the real-time position and status of the steel cage can be checked, and the problem of steel cage jamming can be fundamentally solved.

[0037] 2. This invention provides annular guide wheels on cross-shaped and T-shaped rebar cages, significantly reducing friction between the cage and the trough sidewalls and preventing damage to the trough sidewalls. Existing hoisting techniques frequently cause jamming of special-shaped rebar cages because they have larger radial dimensions than circular cages, making them more susceptible to jamming at the same tilt angle. Therefore, the dual correction and assistance of real-time deviation correction and annular guide wheels can significantly alleviate this jamming problem.

[0038] 3. The present invention pre-models the trough body by combining sonar and electromagnetic waves, and can predict the optimization scheme of the lowering parameters under different geological conditions based on historical data. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present application. For those skilled in the art, other drawings can be obtained based on these drawings without paying any creative labor.

[0040] Figure 1 This is a schematic diagram of the lifting of the steel cage.

[0041] Figure 2 It is a schematic diagram of the formation of a three-dimensional model database.

[0042] Figure 3 It is a schematic diagram of fixed and downward-mounted sonar installation when the three-dimensional model of the cross slot body is established.

[0043] Figure 4 It is a top view schematic diagram of a mobile electromagnetic wave profilometer installed in the slot of a cross slot body (the track is installed in the up and down directions);

[0044] Figure 5 It will Figure 4 The track is installed horizontally.

[0045] In the figure: 1-fixed sonar; 2-lowering sonar; 3-track; 4-electromagnetic wave profiler; 5-main winch; 6-main steel cable; 7-point correction mechanism; 8-lifting mechanism. DETAILED DESCRIPTION

[0046] To make the objectives, technical solutions, and advantages of the embodiments of the present application more clear, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Generally, the components of the embodiments of the present application described and shown in the drawings herein can be arranged and designed in various different configurations.

[0047] Therefore, the following detailed description of the embodiments of the present application provided in the accompanying drawings is not intended to limit the scope of the present application for protection, but merely represents selected embodiments of the present application. All other embodiments obtained by persons of ordinary skill in the art based on the embodiments in the present application without making any creative efforts shall fall within the scope of protection of the present application.

[0048] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, it does not need to be further defined or explained in subsequent drawings.

[0049] In the description of this application, it should be noted that if the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. appear, the orientation or position relationship indicated is based on the orientation or position relationship shown in the accompanying drawings, or the orientation or position relationship in which the product of the application is usually placed when in use. It is only for the convenience of describing this application and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation. Therefore, it cannot be understood as a limitation on this application. In addition, if the terms "first", "second", etc. appear in the description of this application, they are only used to distinguish the description and cannot be understood as indicating or implying relative importance.

[0050] Furthermore, the use of terms such as "horizontal" and "vertical" in the description of this application does not necessarily imply that a component must be absolutely horizontal or suspended, but rather that it can be slightly tilted. 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.

[0051] It should also be noted that, unless otherwise expressly specified or limited, the terms "disposed," "installed," "connected," and "connected" should be understood broadly. For example, they may refer to fixed connections, detachable connections, or integral connections; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; and internal connections between two components. A person of ordinary skill in the art will understand the specific meanings of the above terms in this application based on the specific circumstances.

[0052] Example 1:

[0053] This embodiment provides a method for lowering and correcting a special-shaped steel cage. Multimodal modeling is used to obtain the structure of a trough at different depths. A sensor assembly is then used to detect the depth and posture of the steel cage. The posture of the steel cage is adjusted by comparing the deviation between the current posture vector of the steel cage and the trough axis to be reached. The method further includes the following steps:

[0054] Step STP100: System setup: A fixed sonar 1 and a mobile electromagnetic wave profiler are respectively arranged at the slot of the tank body where the steel cage is to be lowered. The fixed sonar 1 includes four fixed sonar probes installed in a cross shape on the edge of the tank body side wall. The electromagnetic wave profiler 4 moves along a trajectory that covers the central axis of the slot.

[0055] About the installation method of fixed sonar 1 Figure 4-Figure 5 As shown, the fixed sonar 1 in this embodiment is composed of four sonar probes, which are respectively installed at relative positions near the edge of the slot. Taking a circular slot as an example, the fixed sonar 1 is installed at the two ends of two mutually perpendicular diameters, for example, the upper, lower, left and right positions. Taking a cross slot as an example, the four sonar probes are installed as follows: Figure 4 and Figure 5 If the tank is rectangular, the four sonar probes can be installed at the four corners or at the midpoints of the four sides. In this embodiment, the fixed sonar 1 uses a sonar array that can penetrate mud. Specifically, it uses a professional-grade multi-beam sonar, model Teledyne RESON SeaBat T50-P. To achieve better detection results in mud, the operating frequency is adjusted to 200-400kHz, the number of beams is 512, and the mud density is 1.3g / cm 3 The measuring range is about 150m in an environment with an axial resolution of 5mm and a lateral resolution of 10mm. The multi-beam sonar array has a built-in sound velocity profiler SVP to facilitate real-time correction of the propagation speed of sound waves in mud.

[0056] The moving track of the electromagnetic wave profiler 4 covers the central axis of the slot, which should be understood as follows: no matter what shape the cross section of the slot is, the electromagnetic wave profiler 4 can effectively cover the entire slot on the moving track. Figure 4-5 Taking the cross-shaped trough as an example, the moving trajectory of the electromagnetic wave profiler 4 is the horizontal and vertical center axis of the trough. The electromagnetic wave profiler 4 used is the IDS GeoRadar HYDRApro GPR, with a frequency range of 10-500MHz. In this embodiment, the mud environment is used, and the 50MHz low-frequency mode is preferably used. When the mud dielectric constant is less than 15, the penetration depth can reach 200m, and the sampling data density is 20 sampling points per meter. It is installed in the following Figure 4-Figure 5It reciprocates along the track 3 shown, providing full coverage of the entire slot. To achieve better results and to help the fixed sonar 1 and electromagnetic profiler 4 adjust to the optimal frequency for different slurries, a mud parameter monitoring module can be added. Specifically, an OFI Testing Equipment FANN2900HPHT rheometer can be used to monitor mud parameters during testing or before slot modeling or cage lowering. This helps better align the parameters of the slot scanning unit and achieve better modeling results. Of course, since preliminary geological surveys have already been conducted during the slot excavation process, the preliminary stratigraphic structure has been determined, and the selected mud parameters are known, mud parameter monitoring is not mandatory. However, during the slot excavation process, the cleaning of the node piles may cause contamination and dilution of the mud, thereby changing the original mud parameter properties. To meet the needs of precise adjustment, adding a mud parameter monitoring module is also a means of increasing efficiency.

[0057] Step STP200: Establish a tank model. Use a tank scanning unit including a fixed sonar and a mobile electromagnetic profiler GPR to scan the tank. Then, fuse the acquired sonar data and electromagnetic wave data to establish a spatial coordinate system W with the fixed sonar as the origin, and form a three-dimensional point cloud model of the tank S(z) = {(x i ,y i ,z i )|i=1,2,3,…n}, complete the three-dimensional model construction; the three-dimensional model in this embodiment adopts the method of fusing sonar data and electromagnetic wave data based on the weight distribution fusion algorithm, which can be expressed as

[0058] P 融合 (z)=ω1(z)P GPR (z)+ω2(z)P sonar (z)

[0059] Among them, P 融合 (z) represents the fused data, P GPR (z) represents electromagnetic wave data, P sonar (z) represents sonar data, ω1 represents electromagnetic wave weight, and ω2 represents sonar data weight;

[0060]

[0061] Among them, SNR i(z) represents the signal-to-noise ratio, which comes from the original signal of the sensor; z represents the current detection depth; it is worth noting that the current sensor components only include fixed sonar and mobile electromagnetic wave profiler. If the sensor components also include sensors of other modalities, the above-mentioned weight distribution fusion algorithm can also be used to perform data fusion. The more data modalities are fused, the more accurate the fused data obtained and the better the twin responsiveness.

[0062] Step STP300: tank axis fitting, using improved B-spline curve to fit the longitudinal axis C(z) of the tank model.

[0063]

[0064] Among them, N i,p is the p-order B-spline basis function, Q i are the coordinates of the control points;

[0065] Step STP300: Determine the posture of the steel cage. Use the lifting device and the point correction mechanism to lift the first section of the steel cage vertically. The line connecting the lifting device and the connection point on the top of the first section of the steel cage is rectangular. The bottom of the first section of the steel cage is equipped with a well radar and a downward-mounted sonar 2 that are connected to the control center. Figure 3 As shown in the figure, the inertial navigation system INS modules are installed on the top and bottom of the steel cage respectively, and the tilt sensor array is installed along the length of the steel cage; the real-time position vector of the current steel cage is obtained through the inertial navigation system INS module and the tilt sensor array

[0066]

[0067] Among them, X, Y, Z are the center point O of the bottom of the current steel cage B In the spatial coordinate system W, α, β, and γ are the yaw angle, pitch angle, and roll angle of the reinforcement cage axis, respectively;

[0068] On the other hand, the well radar and the lowered sonar 2 are not only used to provide real-time feedback on the position of the steel cage, but can also provide further tank data for the revision of the 3D model in step STP200. Figure 2As shown; the effective detection or scanning depths of the track-moving GPR and fixed sonar are 50m and 150m respectively. Even if their frequencies are optimally matched to the current mud parameters, their effective detection depth is limited, so accurate data cannot be obtained for the part of the tank that exceeds the depth. In this case, it is necessary to add a lowered sonar. By lowering the sonar, its effective detection depth can also be effectively increased, reaching a range of 50m-200m; the well radar is installed at the bottom of the steel cage. As the steel cage is lowered, the tank structure at the deepest position of the tank can be detected, so that a more accurate three-dimensional model can be updated using data fusion algorithms and weight matching; this is the innovation of the multi-modal, multi-mode, dynamic and static combined detection and feedback of the present invention. For a more intuitive understanding, refer to the sensor deployment and division of labor shown in Table 1 below to see the complementary role of multi-modal sensors.

[0069]

[0070] As shown in Table 1 above, the data collected by four different types of sensors installed at different locations can cover a tank body with a depth of up to 200m. Compared with the existing method of lowering the steel cage based on manual experience, the efficiency and accuracy are greatly improved.

[0071] Step STP400, obtain the external force vector of the steel cage, and obtain the external force vector F of the steel cage by establishing a dynamic model of the steel cage under mud ext ,

[0072]

[0073] Among them, M represents the mass matrix of the steel cage, which includes the composite matrix of the steel cage's own mass and the additional hydrodynamic mass; C represents the damping matrix, which includes the internal damping of the structural material and the viscous damping of the mud; K represents the stiffness matrix, which reflects the ability of the steel cage to resist deformation; It should be noted that q here should be understood as a generalized coordinate, as a description of the system's degree of freedom, used to fully characterize the movement and deformation state of the steel cage in three-dimensional space, with 6 degrees of freedom, namely movement along the X, Y, and Z axes and rotation around the X, Y, and Z axes. For ease of understanding, according to the resultant external force vector F ext The components of , can be calculated by components, specifically:

[0074] F ext =F g +F b +F drag +F contact

[0075] Among them, F g Indicates gravity, i.e. the weight of the steel cage; F brepresents the buoyancy, i.e. the Archimedean buoyancy of the steel cage in the mud; F drag Indicates fluid resistance, resistance caused by mud flow, F contact is the contact force, i.e., the contact force between the steel cage and the trench wall. The above components are calculated using an algorithm pre-set in the system control center. The calculations are based on mud density data, the mud resistance coefficient calibrated through experiments, and the contact stiffness of the trench wall obtained from geological survey reports.

[0076] Step STP500, the steel cage is lowered, and the real-time posture vector of the current tank axis and the steel cage is compared. Calculate the torque M required for correction correct ,

[0077]

[0078] Among them, F i is the tension at each lifting point of the steel cage, r i is the position vector of each hanging point; posture vector The adjustment is very critical.

[0079] The control center first sends a correction signal to the point correction mechanism, and then sends a lowering command to the lifting device after the correction is completed, until the current trough axis and the real-time posture vector of the steel cage are aligned. When the deviation between the two reaches the system preset correction value, the lifting device is stopped and the correction of this step is repeated until the top of the current steel cage exceeds the ground height by 1m. Figure 1 As shown, when the entire steel cage is lifted up and down, the main hoist 5 drives the main steel cable 6 to synchronously lift and lower the point deviation correction mechanism 7 together with the steel cage. At this time, for the steel cage, only the vertical force is applied to the steel cage, and it does not participate in the angle adjustment and has no correction function. When correction is required, refer to Figure 1 As shown, the point correction mechanism 7 applies vertical pulling force to the steel cage independently through the lifting mechanism 8 arranged according to the four corners of the square, thereby adjusting the points of the four steel cages up and down, thereby changing the posture of the steel cage to achieve the correction effect, so that the steel cage can match the current trough axis position, avoiding the problem of jamming due to the skewness of the steel cage and the inability to lower the steel cage normally.

[0080] In step STP600, the steel cages are docked and fixed using a ground fixing device. The point-correction mechanism is released, and another section of the steel cage is lifted and fixed to the current one. The ground fixing device is then released and step STP500 is executed until the steel cage touches the bottom of the trough, completing the lowering of the steel cage.

[0081] Preferably, in order to reduce the problem of decreased accuracy of the tank body three-dimensional point cloud model S(z) caused by data acquisition distortion due to errors, the step of optimizing the tank body three-dimensional point cloud model S(z) in step STP200 is further included. Specifically, the RANSAC algorithm is used to remove abnormal points using the following expression:

[0082]

[0083] Here, ρ(·) represents the robust loss function, and a, b, c, and d represent the coefficients of the plane equation in three-dimensional space.

[0084] The present invention also provides another method for fitting the tank axis after removing abnormal points based on the RANSAC algorithm. Specifically, the tank axis fitting step in step STP300 is replaced with the following steps:

[0085] Step STP310: Establish the coordinates of the axis point at any depth in the X-axis direction and the Y-axis direction respectively:

[0086] x=f(z)=a0+a1z+a2z 2

[0087] y=g(z)=b0+b1z+b2z 2

[0088] Where a0, b0 represent the initial offset of the axis at the notch z = 0; a1, b1 represent the linear slope of the axis with depth; a2, b2 represent the curvature of the axis, which is used to reflect the degree of axis bending;

[0089] Step STP320, the 3D point cloud of the tank after elimination by RANSAC algorithm {(x i ,y i ,z i )}Use the least squares method to construct the matrix equation:

[0090] By solving the matrix inversion or QR decomposition, the coefficients a0, a1, a2 and b0, b1, b2 can be obtained, thereby solving the coordinates of the axis point at any depth.

[0091] To further reduce the risk of the rebar cage becoming stuck during lowering due to poor verticality or tilting of the trough, in this embodiment, an annular guide wheel assembly is installed along the length of each cage sidewall, with an axial distance of 5-15m between adjacent guide wheels. These annular guide wheels are located on the outside of the cage, contacting the trough sidewalls before the cage and arranged along the length. Regardless of the length of the cage, they effectively provide auxiliary support and reduce the pressure required to correct deviation. With the addition of the annular guide wheel assembly, even if the cage approaches the trough sidewall or is bent due to a non-straight trough axis, which inevitably leads to contact between the cage and the trough during lowering, the frictional resistance between the cage and the trough sidewall is effectively reduced, facilitating the proper lowering of the cage.

[0092] During the lowering process, the part of the rebar cage most likely to interfere with the trough is the bottom. Because the rebar cage itself lacks guidance, if it deflects within the trough, the bottom of the rebar cage can easily get stuck in the trough sidewalls, causing collapse. Simultaneously, the rebar cage can get stuck in the trough. To address this issue, the present invention employs a flexible hinged structure at the bottom of the rebar cage. The hinged structure is a deformable structure with its own guidance, hinged to the bottom of the rebar cage. This hinged structure allows the bottom of the rebar cage to be hinged to a guide structure that can deflect within a certain range. The sidewalls and bottom of the guide structure utilize smooth curved surfaces to achieve interference guidance, preventing the rebar cage from getting stuck in the trough sidewalls.

[0093] In order to facilitate control and reduce the amount of correction calculation, in this embodiment, the point correction mechanism includes four independent servo hoisting mechanisms or four hydraulic cylinders installed on the same rigid platform.

[0094] The above description is merely a preferred embodiment of the present application and is not intended to limit the present application. Various modifications and variations are possible for those skilled in the art. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present application shall be included within the scope of protection of the present application.

Claims

1. A method for lowering and correcting a special-shaped steel cage, characterized by: Multimodal modeling is used to obtain the different depth structures of the tank body. Then, the sensor assembly is used to detect the depth and posture of the steel cage. By comparing the deviation between the current posture vector of the steel cage and the upcoming tank axis, the posture of the steel cage is adjusted to complete the lowering of the steel cage. The specific steps include: Step STP100: System setup: A fixed sonar and a mobile electromagnetic wave profiler are respectively arranged at the slot of the tank body where the steel cage is to be lowered. The fixed sonar includes four fixed sonar probes installed in a cross shape on the edge of the tank body side wall. The electromagnetic wave profiler's movement trajectory covers the central axis of the slot; Step STP200: Establish a tank model. Use a tank scanning unit including a fixed sonar and a mobile electromagnetic wave profiler to scan the tank. Then, fuse the acquired sonar data and electromagnetic wave data to establish a spatial coordinate system W with the fixed sonar as the origin, and form a three-dimensional point cloud model of the tank S(z)={(x i ,y i ,z i )|i=1,2,3,…n}, complete the three-dimensional model construction; Step STP300: tank axis fitting, using improved B-spline curve to fit the longitudinal axis C(z) of the tank model. Among them, N i,p is the p-order B-spline basis function, Q i are the coordinates of the control points; Step STP300: Determine the posture of the rebar cage. Use a lifting device and a point-correction mechanism to vertically lift the first section of the rebar cage. The line connecting the lifting device and the connection point at the top of the first section of the rebar cage is rectangular. The bottom of the first section of the rebar cage is equipped with a well radar and a downward-mounted sonar connected to the control center, as well as INS modules installed at the top and bottom of the rebar cage, and an inclination sensor array installed along the length of the rebar cage. The current real-time posture vector of the rebar cage is obtained through the INS module and the inclination sensor array. Among them, X, Y, Z are the center point O of the bottom of the current steel cage B In the spatial coordinate system W, α, β, and γ are the yaw angle, pitch angle, and roll angle of the reinforcement cage axis, respectively; Step STP400, obtain the external force vector of the steel cage, and obtain the external force vector F of the steel cage by establishing a dynamic model of the steel cage under mud ext , Among them, M represents the mass matrix of the steel cage, C represents the damping matrix, and K represents the stiffness matrix; Step STP500, the steel cage is lowered, and the real-time posture vector of the current tank axis and the steel cage is compared. Calculate the torque M required for correction correct , Among them, F i is the tension at each lifting point of the steel cage, r i is the position vector of each hanging point; The control center first sends a correction signal to the point correction mechanism, and then sends a lowering command to the lifting device after the correction is completed, until the current trough axis and the real-time posture vector of the steel cage are aligned. When the deviation between the two reaches the system preset correction value, the lifting device is suspended and the correction of this step is repeated until the top of the current steel cage exceeds the ground height by 1m. In step STP600, the steel cages are docked and fixed using a ground fixing device. The point-correction mechanism is released, and another section of the steel cage is lifted and fixed to the current one. The ground fixing device is then released and step STP500 is executed until the steel cage touches the bottom of the trough, completing the lowering of the steel cage.

2. The method for lowering and correcting a special-shaped steel cage according to claim 1, characterized in that: The step of optimizing the three-dimensional point cloud model S(z) of the tank body in step STP200 is also included. Specifically, the RANSAC algorithm is used to remove abnormal points using the following expression: Here, ρ(·) represents the robust loss function, and a, b, c, and d represent the coefficients of the plane equation in three-dimensional space.

3. The method for lowering and correcting a special-shaped steel cage according to claim 2, characterized in that: Replace the tank axis fitting step in step STP300 with the following steps: Step STP310: Establish the coordinates of the axis point at any depth in the X-axis direction and the Y-axis direction respectively: x=f(z)=a0+a1z+a2z 2 y=g(z)=b0+b1z+b2z 2 Where a0, b0 represent the initial offset of the axis at the notch z = 0; a1, b1 represent the linear slope of the axis with depth; a2, b2 represent the curvature of the axis, which is used to reflect the degree of axis bending; Step STP320, the 3D point cloud of the tank after elimination by RANSAC algorithm {(x i ,y i ,z i )}Use the least squares method to construct the matrix equation: By solving the matrix inversion or QR decomposition, the coefficients a0, a1, a2 and b0, b1, b2 can be obtained, thereby solving the coordinates of the axis point at any depth.

4. A method for lowering and correcting a special-shaped steel cage according to any one of claims 1 to 3, characterized in that: An annular guide wheel group is installed on the side wall of any section of the steel cage along the length direction of the steel cage, and the axial distance between two adjacent guide wheels is 5-15m.

5. A method for lowering and correcting a special-shaped steel cage according to any one of claims 1 to 3, characterized in that: The bottom of the steel cage adopts a flexible hinge structure.

6. The method for lowering and correcting a special-shaped steel cage according to claim 1, characterized in that: The point deviation correction mechanism includes four sets of independent servo hoisting mechanisms or four hydraulic cylinders installed on the same rigid platform.

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