Anchor cable pre-tightening automatic tension distribution device and method

Abstract

The invention relates to the technical field, and particularly discloses an anchor cable pre-tightening automatic tension distribution device and method. Comprising a main oil cylinder, an independent tensioning unit installed on one side of the telescopic end of the main oil cylinder and used for clamping and tensioning a plurality of sets of steel strands, a hydraulic pump station connected with the main oil cylinder and the independent tensioning unit, a monitoring assembly installed on the main oil cylinder and the independent tensioning unit, and a monitoring assembly connected with the main oil cylinder and the independent tensioning unit. The monitoring assemblies are respectively connected with a control unit. Automation, high precision and high efficiency of the anchor cable pre-tightening process can be achieved, and it is ensured that the pre-tightening force height of each steel strand is consistent. The problems of low efficiency and uneven tension caused by traditional manual one-by-one tensioning are thoroughly solved, and the construction quality, efficiency and safety are remarkably improved.

Description

Technical Field

[0001] This invention relates to the field of technology, and more specifically, to an automatic tension distribution device and method for anchor cable pretensioning. Background Technology

[0002] Prestressed anchor cables are widely used in slope protection, foundation pit anchoring, and dam reinforcement projects. The tensioning and pre-tightening of the anchor cables is a crucial step in ensuring their support function; the uniformity of the pre-tightening force directly determines the load-bearing capacity and long-term safety of the entire anchor cable system.

[0003] Currently, construction sites commonly use manual tensioning jacks to tension each steel strand in the anchor cable one by one. This method has the following disadvantages: (1) Low efficiency: Tensioning one strand at a time is time-consuming and laborious, affecting the construction progress.

[0004] (2) Large error: Due to differences in the operator's skill level, proficiency and fatigue level, as well as systematic errors between tools, the preload of each steel strand varies greatly, resulting in uneven tension distribution. One steel strand may be subjected to excessive tension and fail prematurely, while another may be in a slack state and fail to play its full role.

[0005] (3) Safety hazards: Under long-term load, the steel strand with greater stress in the anchor cable system with uneven tension will break first, triggering a chain reaction that leads to the failure of the entire anchor cable system and causes engineering accidents.

[0006] Therefore, developing a device and method that can automatically and synchronously tension multiple steel strands and intelligently distribute the tension to ensure that each steel strand is subjected to uniform force has become a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0007] The technical problem to be solved by the present invention is to provide an automatic tension distribution device and method for anchor cable pre-tightening, so as to realize the automation, high precision and high efficiency of the anchor cable pre-tightening process and ensure that the pre-tightening force of each steel strand is highly consistent; The solution adopted by this invention to solve the technical problem is: on the one hand: An automatic tension distribution device for anchor cable pretensioning includes a main hydraulic cylinder, an independent tensioning unit installed on one side of the telescopic end of the main hydraulic cylinder for clamping and tensioning several groups of steel strands respectively, a hydraulic pump station connected to the main hydraulic cylinder and the independent tensioning unit respectively, a monitoring component installed on the main hydraulic cylinder and the independent tensioning unit, and a control unit connected to the main hydraulic cylinder, the independent tensioning unit and the monitoring component respectively.

[0008] In some possible implementations, the independent tensioning unit includes a mounting base installed at the telescopic end of the main cylinder, a tensioning cylinder mounted on the mounting base for tensioning the steel strand, and clamps corresponding to the tensioning cylinders for clamping the steel strand; the tensioning cylinders and clamps are connected to the control unit.

[0009] In some possible implementations, the monitoring components include a pressure sensor 1 disposed in the oil inlet of each group of tensioning cylinders and connected to the control unit, a pressure sensor 2 disposed in the oil chamber of the main cylinder and connected to the control unit, and a displacement sensor mounted on an independent tensioning unit for detecting the displacement of each group of steel strands.

[0010] In some possible implementations, an oil inlet pipeline is provided between the hydraulic pump station and the main cylinder, and a main oil inlet valve is provided on the oil inlet pipeline. A second oil inlet pipeline is provided between the hydraulic pump station and the multiple sets of tensioning cylinders, and a multi-way diversion and combination valve is provided on the second oil inlet pipeline.

[0011] In some possible implementations, an electro-hydraulic proportional valve connected to the control unit is provided in the oil inlet line of each tensioning cylinder.

[0012] on the other hand: An automatic tension distribution method for anchor cable pretensioning, based on the aforementioned automatic tension distribution device for anchor cable pretensioning, specifically includes the following steps: Step S1: The independent tensioning unit clamps the steel strand; Step S2: The control unit controls the main hydraulic cylinder to perform initial tensioning on the independent tensioning unit and the steel strand, monitors the real-time pressure value in the main hydraulic cylinder of the component, and transmits it to the control unit until the initial tensioning is completed; Step S3: After the initial tensioning is completed, the control unit controls the tensioning of each group of steel strands separately through the tensioning cylinder in the independent tensioning unit; Step S4: During the tensioning process of each group of steel strands, the monitoring component monitors the pressure value inside the tensioning cylinder and the displacement of the steel strand corresponding to the tensioning cylinder, and transmits the data to the control unit. Control unit 5 calculates the actual tension F of each steel strand by using pressure and displacement values. _i Calculate the standard deviation of tension and compare it with the preset tolerance; Step S5: The control unit determines whether the actual tension distribution of each group of steel strands is uniform based on the comparison result between the tension standard deviation and the preset tolerance; if it is not uniform, it adjusts the tension until it meets the requirements. Step S6: Once all the steel strands are tensioned, maintain the hydraulic pressure and permanently lock the steel strands using a self-locking clamp. Step S7: After locking is completed, the control unit controls the hydraulic pump station to fully unload, and then controls all clamps to loosen and separate from the steel strand.

[0013] In some possible implementations, step S5 specifically refers to determining that if the standard deviation of tension is greater than the tolerance, the tension distribution is uneven, and the tensioning cylinder is used to independently adjust the tension of the corresponding steel strand. For steel strands with actual tension greater than target tension, adjust the corresponding electro-hydraulic proportional valve to fine-tune and relieve pressure until the standard deviation of tension is less than or equal to the tolerance. For steel strands with actual tension greater than target tension, adjust the corresponding electro-hydraulic proportional valve to fine-tune the pressure until the tension standard deviation is less than or equal to the tolerance.

[0014] In some possible implementations, the target tension is calculated using the formula F. _target =F _total / N; Among them, F _target For target tension; F _total Total preload for the target; N is the number of steel strands.

[0015] In some possible implementations, the adjustment amount of the electro-hydraulic proportional valve is calculated based on a PID control algorithm, wherein the adjustment amount is the tension deviation e of a single steel strand. _i =F _target -F _i ; Among them, F _i This represents the actual tension.

[0016] In some possible implementations, during the initial tensioning, the control unit opens the main oil inlet valve, and the hydraulic pump station supplies oil to the main oil chamber of the main oil cylinder, driving the independent tensioning unit to move synchronously and perform initial tensioning on all steel strands.

[0017] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention fundamentally solves the problem of uneven tension caused by manual tensioning through real-time monitoring and independent closed-loop control, greatly improving the overall load-bearing capacity and durability of the anchor cable; it also significantly reduces the dependence on the technical level and experience of operators, and reduces human error and labor intensity. Attached Figure Description

[0018] Figure 1 This is a schematic diagram showing the connection relationship between the main hydraulic cylinder and the independent tensioning unit in this invention; Figure 2 for Figure 1 Side view; Figure 3This is a cross-sectional view of the independent tensioning unit in this invention; Figure 4 This is a schematic diagram of the control unit and hydraulic pump station in this invention; in: 1. Main hydraulic cylinder; 2. Independent tensioning unit; 21. Mounting base; 22. Tensioning cylinder; 23. Clamp; 3. Hydraulic pump station; 4. Monitoring components; 41. Pressure sensor one; 42. Pressure sensor two; 5. Control unit; 6. Diverter and combiner valve. Detailed Implementation

[0019] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. The terms "first," "second," and similar terms used in this application do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Similarly, "a" or "one," etc., do not indicate a quantity limitation, but rather indicate the existence of at least one. In the implementation of this application, "and / or" describes the association relationship of related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. In the description of the embodiments of this application, unless otherwise stated, "multiple" means two or more. For example, multiple positioning posts refer to two or more positioning posts. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0020] The present invention will now be described in detail.

[0021] like Figures 1-4 As shown: on the one hand: An automatic tension distribution device for anchor cable pretensioning includes a main cylinder 1, an independent tensioning unit 2 installed on one side of the telescopic end of the main cylinder 1 and used for clamping and tensioning several groups of steel strands respectively, a hydraulic pump station 3 connected to the main cylinder 1 and the independent tensioning unit 2 respectively, a monitoring component 4 installed on the main cylinder 1 and the independent tensioning unit 2, and a control unit 5 connected to the main cylinder 1, the independent tensioning unit 2 and the monitoring component 4 respectively. The independent tensioning unit 2 includes a mounting base 21 installed on the telescopic end of the main cylinder 1, a tensioning cylinder 22 installed on the mounting base 21 for tensioning the steel strand, and a clamp 23 corresponding to the tensioning cylinder 22 for clamping the steel strand; the tensioning cylinder 22 and the clamp 23 are connected to the control unit 5.

[0022] The control unit 5 receives data from the monitoring component 4, which monitors the internal pressure of the main cylinder 1, the internal pressure of the tensioning cylinder 22, and the displacement data of the steel strand under the control of the tensioning cylinder 22. The control unit controls the start-up, shutdown, and unloading of the hydraulic pump station 3, and controls the clamping and releasing of the independent tensioning unit 2, so as to realize the synchronous and independent tensioning of multiple steel strands and the automatic distribution of tension, ultimately making the tension of all steel strands uniform. Before tensioning, the independent tensioning unit 2 is first installed on the main hydraulic cylinder 1, and then one end of the steel strand is clamped through the independent tensioning unit 2. During tensioning, the independent tensioning unit 2 is first controlled by the control unit 5, hydraulic pump station 3, and main oil cylinder 1, thereby achieving synchronous tensioning of all steel strands and eliminating most gaps. During synchronous tensioning, the monitoring component 4 will detect the internal pressure of the tensioning cylinder 22, the internal pressure of the main cylinder 1, and the displacement of each group of steel strands during individual tensioning. The actual tension of each group of steel strands is obtained by the internal pressure of the tensioning cylinder 22 and the displacement of each group of steel strands. Subsequently, the control unit 2 adjusts the tension of each group of steel strands according to the actual tension of all steel strands, so that the tension of all steel strands is uniform. This invention achieves full automation of anchor cable pretensioning, completely solving the problems of low efficiency and uneven tension caused by traditional manual tensioning of individual cables, and significantly improving construction quality, efficiency and safety.

[0023] Specifically, the mounting base 21 is provided with through holes, which are set one-to-one with the steel strands. The tensioning cylinder 22 and the clamp 23 will be installed in the through holes.

[0024] In some possible implementations, the monitoring component 4 includes a pressure sensor 41 disposed on the oil inlet path of each group of tensioning cylinders 22 and connected to the control unit 5, a pressure sensor 42 disposed in the oil chamber of the main cylinder 1 and connected to the control unit 5, and a displacement sensor mounted on the mounting base 21 for detecting the displacement of each group of steel strands. Specifically, pressure sensor 41 is used to detect the actual tension of each steel strand in real time during the tensioning process, thereby calculating the standard deviation of tension of each steel strand; pressure sensor 42 is used to detect the pressure in the oil chamber of the main oil cylinder 1, and through the detection of this pressure, the tensioning control of the independent tensioning unit 2 is realized. The displacement sensor is located at the point where the displacement of the steel strands is measured when each group of steel strands is tensioned separately.

[0025] In some possible implementations, an oil inlet pipeline is provided between the hydraulic pump station 3 and the main cylinder 1, and the hydraulic pump station 3 and the main cylinder 1 are connected by the oil inlet pipeline; a main oil inlet valve is provided on the oil inlet pipeline; the main oil inlet valve is responsible for providing strong tension in the initial stage to realize the synchronous tensioning of the independent tensioning unit 2 and the steel strand; A second oil inlet pipeline is provided between the hydraulic pump station 3 and the multiple sets of tensioning cylinders 22. The connection between the hydraulic pump station 3 and the multiple sets of tensioning cylinders 22 is realized through the oil inlet pipeline. A multi-way diversion and combination valve 6 is provided on the second oil inlet pipeline. The diversion and combination valve 6 realizes the supply of fluid to each set of tensioning cylinders 22 and realizes the tension control of each set of steel strands. A second pressure sensor 42 can be installed on the second oil inlet pipeline.

[0026] In some possible implementations, an electro-hydraulic proportional valve connected to the control unit 5 is provided in the oil inlet line of each tensioning cylinder 22; an electro-hydraulic proportional valve controlled by the control unit 5 is provided in the oil inlet line of each tensioning cylinder 22, which allows the control unit to independently and continuously fine-tune the tension of any steel strand, thereby realizing that the electro-hydraulic proportional valve will control the oil under the control of the control unit 5, and finally achieving tension balance of all steel strands.

[0027] Preferably, there are multiple sets of tensioning cylinders 22, with their axes arranged along the axis of the main cylinder 1. The multiple sets of tensioning cylinders 22 are evenly arranged on the mounting base 21 and are equidistant from the axis of the mounting base 21. The mounting base 21 is installed on the telescopic end of the main cylinder 1, and a flange for installing the mounting base 21 is provided on the telescopic end. The improvement of this invention does not lie in the specific structure of the clamp, main cylinder 1, tensioning cylinder 22, electro-hydraulic proportional valve, and flow divider / combiner valve 6, and will not be described in detail.

[0028] on the other hand: An automatic tension distribution method for anchor cable pretensioning, specifically, in this embodiment, the target total pretension force of the anchor cable is F. _total The anchor cable has N steel strands, and the target tension of a single steel strand is F. _target F _target =F _total / N; Based on the above-described automatic tension distribution device for anchor cable pretensioning; specifically including the following steps: Step S1: Independent tensioning unit 2 clamps all steel strands; Step S2: Control unit 5 controls main cylinder 1 to perform initial tensioning on independent tensioning unit 2 and steel strand. Monitoring component 4 collects the internal pressure value of main cylinder in real time and sends it to control unit 5 until the tension force reaches 30% of the pretension force, and the initial tensioning is completed. Specifically, during the initial tensioning, the control unit 5 opens the main oil inlet valve, and the hydraulic pump station 3 supplies oil to the main oil chamber of the main oil cylinder 1, driving the independent tensioning unit 2 to move synchronously and perform initial tensioning on all steel strands. Step S3: After the initial tensioning is completed, each group of steel strands is tensioned separately using an independent hydraulic cylinder; Step S4: During the tensioning process of each group of steel strands, pressure sensor 41 monitors the pressure value in the corresponding tensioning cylinder 22, and displacement sensor monitors the displacement of the steel strand corresponding to the tensioning cylinder 22 and transmits it to the control unit. Control unit 5 calculates the actual tension F of each steel strand by using the pressure value inside the tensioning cylinder 22 and the displacement of the steel strand corresponding to the tensioning cylinder 22. _i Through actual tension F _i The standard deviation of tension σ is calculated and compared with the preset tolerance ε. Step S5: Control unit 5 determines whether the actual tension distribution of each group of steel strands is uniform based on the comparison result between the tension standard deviation σ and the preset tolerance ε; if it is not uniform, it adjusts until it meets the requirements. The adjustment amount of the electro-hydraulic proportional valve is calculated based on a PID control algorithm, where the adjustment amount is the tension deviation of a single steel strand, and the formula for calculating the tension deviation of a single steel strand is e. _i =F _target -F _i ;e _i For tension deviation; Specifically, if σ>ε, it is determined that the tension distribution is uneven, and the tensioning cylinder 22 is used to independently adjust the force of the corresponding steel strand; Among them, for F _i >F _target If the tension of the steel strand is too high, adjust the corresponding electro-hydraulic proportional valve according to the tension deviation to fine-tune and relieve pressure until σ≤ε. For F _i >F _target If the steel strand has insufficient tension, then adjust the corresponding electro-hydraulic proportional valve to fine-tune the pressure increase according to the tension deviation until σ≤ε. Step S6: After all the steel strands are tensioned, maintain the hydraulic pressure and permanently lock the steel strands under the control of the control unit 5 through the self-locking clamp 23. Step S7: After locking is completed, the control unit controls the hydraulic pump station to fully unload, and then controls all clamps 23 to loosen and separate from the steel strand.

[0029] This invention is not limited to the specific embodiments described above. The invention extends to any new feature or combination disclosed in this specification, as well as any new method or process step or combination disclosed herein.

Claims

1. An automatic tension distribution device for anchor cable pre-tensioning, characterized in that, It includes a main hydraulic cylinder, an independent tensioning unit installed on one side of the telescopic end of the main hydraulic cylinder for clamping and tensioning several groups of steel strands respectively, a hydraulic pump station connected to the main hydraulic cylinder and the independent tensioning unit respectively, a monitoring component installed on the main hydraulic cylinder and the independent tensioning unit, and a control unit connected to the main hydraulic cylinder, the independent tensioning unit and the monitoring component respectively.

2. The automatic tension distribution device for anchor cable pre-tensioning according to claim 1, characterized in that, The independent tensioning unit includes a mounting base installed at the telescopic end of the main cylinder, a tensioning cylinder installed on the mounting base for tensioning the steel strand, and a clamp corresponding to the tensioning cylinder for clamping the steel strand; the tensioning cylinder and the clamp are connected to the control unit.

3. The automatic tension distribution device for anchor cable pre-tensioning according to claim 2, characterized in that, The monitoring components include a pressure sensor 1 installed in the oil inlet of each group of tensioning cylinders and connected to the control unit, a pressure sensor 2 installed in the oil chamber of the main cylinder and connected to the control unit, and a displacement sensor installed on an independent tensioning unit for detecting the displacement of each group of steel strands.

4. The automatic tension distribution device for anchor cable pre-tensioning according to claim 2, characterized in that, An oil inlet pipeline is provided between the hydraulic pump station and the main oil cylinder, and a main oil inlet valve is provided on the oil inlet pipeline. A second oil inlet pipeline is provided between the hydraulic pump station and the multiple sets of tensioning cylinders, and a multi-way diversion and combination valve is provided on the second oil inlet pipeline.

5. The automatic tension distribution device for anchor cable pre-tensioning according to claim 4, characterized in that, An electro-hydraulic proportional valve connected to the control unit is installed in the oil inlet line of each tensioning cylinder.

6. An automatic tension distribution method for anchor cable pre-tightening, characterized in that, An automatic tension distribution device for anchor cable pretensioning according to any one of claims 1-5; specifically comprising the following steps: Step S1: The independent tensioning unit clamps the steel strand; Step S2: The control unit controls the main hydraulic cylinder to perform initial tensioning on the independent tensioning unit and the steel strand, monitors the real-time pressure value in the main hydraulic cylinder of the component, and transmits it to the control unit until the initial tensioning is completed; Step S3: After the initial tensioning is completed, the control unit controls the tensioning of each group of steel strands separately through the tensioning cylinder in the independent tensioning unit; Step S4: During the tensioning process of each group of steel strands, the monitoring component monitors the pressure value inside the tensioning cylinder and the displacement of the steel strand corresponding to the tensioning cylinder, and transmits the data to the control unit. The control unit calculates the actual tension of each steel strand by using pressure value and displacement amount, calculates the tension standard deviation based on the actual tension, and compares the tension standard deviation with the preset tolerance. Step S5: The control unit determines whether the actual tension distribution of each group of steel strands is uniform based on the comparison result between the tension standard deviation and the preset tolerance; if it is not uniform, it adjusts the tension until it meets the requirements. Step S6: Once all the steel strands are tensioned, maintain the hydraulic pressure and permanently lock the steel strands using a self-locking clamp. Step S7: After locking is completed, the control unit controls the hydraulic pump station to fully unload, and then controls all clamps to loosen and separate from the steel strand.

7. The automatic tension distribution method for anchor cable pre-tightening according to claim 6, characterized in that, Specifically, step S5 refers to determining that if the standard deviation of tension is greater than the tolerance, the tension distribution is uneven, and the tensioning cylinder is used to independently adjust the tension of the corresponding steel strand. For steel strands with actual tension greater than target tension, adjust the corresponding electro-hydraulic proportional valve to fine-tune and relieve pressure until the standard deviation of tension is less than or equal to the tolerance. For steel strands with actual tension greater than target tension, adjust the corresponding electro-hydraulic proportional valve to fine-tune the pressure until the tension standard deviation is less than or equal to the tolerance.

8. The automatic tension distribution method for anchor cable pre-tightening according to claim 7, characterized in that, The formula for calculating the target tension is F. _target =F _total / N; Among them, F _target For target tension; F _total Total preload for the target; N is the number of steel strands.

9. The automatic tension distribution method for anchor cable pre-tightening according to claim 8, characterized in that, The adjustment amount of the electro-hydraulic proportional valve is calculated based on a PID control algorithm, wherein the adjustment amount is the tension deviation e of a single steel strand. _i =F _target -F _i ; Among them, F _i This represents the actual tension.

10. The automatic tension distribution method for anchor cable pre-tightening according to claim 7, characterized in that, During the initial tensioning, the control unit opens the main oil inlet valve, and the hydraulic pump station supplies oil to the main oil chamber of the main oil cylinder, driving the independent tensioning unit to move synchronously and perform initial tensioning on all steel strands.

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