Experimental method for dynamic response of anchor failure and progressive collapse of suspended tunnel

Abstract

The present invention discloses a method for testing the dynamic response of anchor failure and continuous collapse of a suspended tunnel. The test device used includes a test water tank, a test model pipe body, an anchor system and an anchor continuous collapse device. The test model pipe body is installed in the test water tank through the anchor system. The anchor system includes an anchor and a cable tensioner. The cable tensioner is installed on the anchor. The cable tensioner is used to adjust the anchor. The anchor continuous collapse device includes multiple anchor breaking trigger devices. Each anchor breaking trigger device is installed on the anchor. The anchor breaking trigger device includes a tension sensor and a control circuit device. The tension sensor is used to monitor the tension of the anchor. The control circuit device is connected to the tension sensor. The control circuit device breaks the anchor according to the tension value measured by the tension sensor. The present invention can simulate the breaking of the anchor cable and the continuous collapse of the anchor cable through multiple groups of tension sensors and control circuit devices, and analyze the residual system dynamic response after the anchor cable fails.

Description

Technical Field

[0001] The invention relates to the technical field of suspended tunnels, in particular to a test device and a test method for dynamic response of anchor failure and continuous collapse of suspended tunnels. Background Art

[0002] The suspended tunnel, also known as the "Archimedes Bridge", is an innovative transportation structure that spans long and deep waters. The suspended tunnel is composed of a tunnel body, anchor cables, foundations, and connections on both sides. Among them, the anchor cables are mainly used to connect the tunnel body to the seabed, and together with the anchor foundation, they constitute an anchoring system. All external loads are borne by the anchoring system. It can be seen that the anchor cables play a vital role in the construction and operation of the suspended tunnel. However, since the suspended tunnel has been in the offshore marine environment for a long time, the anchor cables will suffer from cross-sectional loss or even breakage under complex factors such as wave and current loads, earthquakes, corrosion, wear, or submarine collisions, that is, the anchor cables fail. Once the anchor cable fails, the original equilibrium state of the tunnel system will be broken, and the anchor tension relaxation phenomenon is prone to occur, which seriously threatens its normal construction and operation. It is more worth emphasizing that the failure of the anchor cable may also cause the continuous collapse of the entire suspended tunnel, that is, the local failure causes the destruction of the overall structure, which will have catastrophic consequences for the entire tunnel. In addition, it is extremely difficult to safely handle it in the complex offshore deep-water environment, and it faces a series of scientific, technical and engineering problems. It can be seen that the dynamic response analysis of the failure of suspended tunnel anchor cables and their progressive collapse cannot be ignored and requires our in-depth research. Summary of the invention

[0003] The purpose of the present invention is to provide a test device and a test method for dynamic response of anchor cable failure and continuous collapse of a suspended tunnel in view of the problems existing in the prior art.

[0004] In order to achieve the above object, the technical solution adopted by the present invention is:

[0005] A suspended tunnel anchor failure and continuous collapse dynamic response test device, comprising a test water tank, a test model pipe body, an anchor system and an anchor continuous collapse device, wherein the test model pipe body is installed in the test water tank through the anchor system, the anchor system comprises an anchor cable and a cable tensioner, the cable tensioner is installed on the anchor cable, the cable tensioner is used to adjust the anchor cable, thereby changing the initial tension stress of the anchor cable, the anchor continuous collapse device comprises a plurality of anchor cable breaking trigger devices, each of the anchor cable breaking trigger devices is installed on the anchor cable, the anchor cable breaking trigger device comprises a tension sensor and a control circuit device, the tension sensor is used to monitor the tension of the anchor cable, the control circuit device is connected to the tension sensor, and the control circuit device is used to break the anchor cable according to the tension value measured by the tension sensor.

[0006] The existing test device that achieves the effect of anchor cable breaking by increasing or decreasing air pressure has a certain time delay and cannot achieve force-controlled and time-controlled cable breaking, so it cannot simulate the dynamic response of the suspended tunnel anchor cable after instantaneous breaking in the test. The dynamic response test device described in the present invention monitors data in real time through a tension sensor and controls the power on and off through a control circuit device to achieve the effect of instantaneous anchor cable breaking, thereby improving the authenticity and accuracy of data collection, and can simulate the dynamic response of the suspended tunnel anchor cable after instantaneous breaking in the test; and the anchor cable breaking trigger device has a simple structure, is easy to install and operate, and the anchor cable breaking trigger condition can be self-adjusted, so that the fracture test of different anchor cable tensions can be achieved, which can be used repeatedly and has low cost.

[0007] Furthermore, by setting up multiple groups of tension sensors and control circuit devices, the continuous collapse effect of the suspended tunnel can be achieved, and the transient dynamic response of the remaining system after the continuous failure of the anchor cables can be truly simulated and analyzed, providing a reference for the design and construction of the suspended tunnel.

[0008] Furthermore, the cable tensioner may be a turnbuckle.

[0009] As a preferred embodiment of the present invention, the control circuit device includes a de-energized electromagnet and an iron block installed on the anchor cable, one end of the anchor cable is connected to the de-energized electromagnet, and the other end is connected to the iron block, and the de-energized electromagnet is connected to a comparison circuit, the comparison circuit includes a voltage comparator, a relay and a resistor, and the comparison circuit outputs high and low levels through the voltage comparator to control the opening and closing of the relay, and then control the magnetism of the de-energized electromagnet.

[0010] The tension value can be observed on the digital display of the tension sensor, and the tension sensor is connected to a control circuit device. The device first uses the voltage comparator to realize power off or power on, and then realizes the magnetic or non-magnetic nature of the de-energized electromagnet through the relay, so that the iron block will be adsorbed and separated from the electromagnet. Separation indicates that the anchor cable is disconnected, that is, the control function of cable breakage is realized. The trigger condition for the anchor cable to break is the set anchor cable failure threshold tension. When the tension does not reach the set value, the relay cannot start working, the de-energized electromagnet appears to be magnetic, the de-energized electromagnet is attracted to the iron block, and the anchor cable is in a normal state. When the tension reaches the set value, the relay starts working, the de-energized electromagnet appears to be non-magnetic, and the de-energized electromagnet is separated from the iron block, thereby controlling the occurrence of cable breakage.

[0011] The tension sensor uses a resistive strain type tension sensor, which is a sensor composed of a measurement circuit composed of a resistance strain gauge and an elastic sensitive element. When the elastic sensitive element is subjected to external tension, strain will be generated, and the resistance strain gauge attached to the surface will also be strained, and the resistance value will change.

[0012] The energized electromagnet can maintain its magnetism only when it is continuously energized. However, continuous energization will cause the energized electromagnet to heat up and reduce its magnetism, while the de-energized electromagnet can maintain its magnetism for a long time.

[0013] As a preferred solution of the present invention, the comparison circuit structure is as follows: the resistance value of the strain gauge of the tension sensor is Rz, and the resistance value Rz changes with the change of the external force, and the magnitude of the change value is proportional to the magnitude of the tension. When a 5V voltage is applied to the strain gauge resistance value Rz and the resistor R1, there is a voltage VA at point A. When the tension of the anchor cable increases, the resistance value of the resistor Rz decreases, causing VA to rise. When the anchor cable tension reaches a certain set value, this tension value is the set threshold tension FTH. Resistor R2 and the sliding resistor Rp form a voltage divider. Adjusting Rp can change the voltage of VB. The VB value is the threshold voltage set by the comparator, called VTH. Once the tension of the anchor cable exceeds the threshold tension FTH, VA>VTH, the comparator outputs a low level, the relay K is energized, the de-energized electromagnet is energized and loses its magnetism, so that the de-energized electromagnet is separated from the iron block, thereby achieving the purpose of breaking the anchor cable.

[0014] As a preferred solution of the present invention, the dynamic response test device further comprises a sensor measuring instrument, and the sensor measuring instrument comprises a gyroscope and a non-contact strain displacement measuring device.

[0015] The gyroscope is installed at the center of gravity of the test model tube body. The gyroscope can be used to measure the angular velocity of rotation around the axis, and the rotation angle around the axis can be obtained by deduction. The spatial posture at the center of gravity of the test model tube body is calculated, so that the rotation amount of the suspended tunnel test model can be calculated. The gyroscope can accurately measure the rotation amount of the center of gravity of the suspended tunnel. By measuring the angular velocity of the test model tube body, the three rotation states of the test model tube body, namely pitch, roll and yaw, can be determined. The gyroscope has the advantages of small size, simple structure, high precision, etc.

[0016] Although the gyroscope can also obtain the acceleration data of the test model pipe body, and use its acceleration for secondary integration to obtain three translational time domain responses, the acceleration obtained by the gyroscope is not accurate enough, and the translational time domain response needs to be obtained through secondary integration of the acceleration, which is difficult and the accuracy is not high. Therefore, the present invention adopts a non-contact strain displacement measurement device to obtain the translational time domain response of the test model pipe body, that is, the horizontal translational time domain and the vertical translational time domain response. Not only does it not need to consider the complex requirement that the sensor needs to be waterproofed, it is easy to install and operate, and it can also accurately use computer algorithms to solve the translational time domain response of the test model pipe body, solving the problem that the gyroscope cannot accurately measure the translational time domain response. Finally, the response results are graphically displayed on the computer, which has the advantages of intuitive and visible images and high measurement accuracy, and is convenient for better understanding and analysis of the performance of the model pipe body.

[0017] The non-contact strain displacement measuring device includes at least two cameras and a plurality of target points arranged on the cross section of the test model tube body. The target point and the cross section of the test model tube body move in coordination and do not move at all during the measurement process, so that the motion posture of the test model tube body is consistent with the motion posture of the target point. The non-contact strain displacement measuring device samples the target point at high speed through the camera, and performs a comparison algorithm through the collected image-related points to calculate the displacement and strain distribution of the target point surface.

[0018] The wall of the sink can be made of transparent glass, and two cameras are installed on one side of the sink.

[0019] As a preferred solution of the present invention, the camera is a high-speed camera, so that high-speed sampling can be achieved and samples can be captured at a high frequency.

[0020] As a preferred embodiment of the present invention, the non-contact strain displacement measuring device further comprises background paper, the background paper is pasted on the cross section of the test model tube body, and the target point is arranged on the background paper. The background paper is pure color paper as much as possible, and the color of the background paper is in sharp contrast with the color of the target point as much as possible, so as to facilitate sampling of the target point.

[0021] As a preferred embodiment of the present invention, the number of the target points is 3, and the 3 target points are arranged non-collinearly.

[0022] As a preferred solution of the present invention, the sensing and measuring instrument also includes a wave height meter and a flow rate meter installed in the test water tank, which can obtain important parameters of the test such as wave height and flow rate.

[0023] As a preferred solution of the present invention, the tension sensor is installed above the water surface to realize the conversion of underwater measurement into above-water measurement, which not only meets the measurement accuracy requirements but also eliminates the need to consider waterproof measures, making the installation operation more convenient.

[0024] As a preferred embodiment of the present invention, the mooring system further comprises a false bottom, a pulley and a fixed bracket, wherein the false bottom is fixed to the bottom of the test water tank, the fixed bracket is fixed above the water surface, and the anchor cable is connected to the fixed bracket after passing through the pulley. By setting the fixed bracket and the pulley above the water surface, a part of the anchor cable can be exposed above the water surface, so that the tension sensor can be installed on the anchor cable exposed above the water surface to achieve water measurement.

[0025] As a preferred solution of the present invention, the pulley can slide along the false bottom, thereby changing the force transmission direction of the anchor cable.

[0026] As a preferred embodiment of the present invention, the dynamic response test device also includes a restraint device, which includes a tension spring and a torsion spring. The tension spring is installed in the lateral swing, longitudinal swing and vertical swing directions of the test model pipe body, and the tension spring is used to simulate the restraining effect of adjacent pipe sections on the lateral swing, longitudinal swing and vertical swing of the test model pipe body. The torsion spring is installed in the roll, pitch and yaw directions of the test model pipe body, and the torsion spring is used to simulate the restraining effect of adjacent pipe sections on the roll, pitch and yaw of the test model pipe body.

[0027] Suspended tunnels are ultra-long span traffic structures. Due to the limited test site, segmental pipe segment model experiments are mostly used. In actual engineering, the two ends of the full-scale suspended tunnel are anchored in the land rock mass. The constraints at both ends of the full-scale suspended tunnel can be considered as simply supported constraints. However, for the suspended tunnel segment model, the constraints at both ends of the segment suspended tunnel model come from the constraints of its adjacent pipe segments on it. This constraint is related to the length of the suspended tunnel, the anchoring form, the structural form, etc. Therefore, the constraints at both ends of the suspended tunnel segment model test cannot be considered as simple simply supported constraints or full freedom.

[0028] In order to accurately simulate the constraints at both ends of the suspended tunnel segment model test, improve the test accuracy, and be close to engineering practice, the present invention specially designs a special model constraint device, which controls the size of the constraint effect through the axial stiffness and torsional stiffness of the 6-directional springs, thereby more realistically and flexibly simulating the actual constraint conditions of the test model pipe body.

[0029] As a preferred embodiment of the present invention, the length of the water tank is much larger than its cross-sectional size. A wave-making and flow-generating system and a wave-breaking system are provided in the test water tank. The wave-making and flow-generating system and the wave-breaking system are respectively arranged at two ends of the test water tank. The wave-making and flow-generating system can simulate the dynamic response of the physical model of the suspended tunnel under the action of waves and flows. The wave-breaking system is used to reduce the reflection effect of oncoming waves, thereby improving the authenticity of the data collected by the measuring device.

[0030] As a preferred embodiment of the present invention, the wave-breaking system is a gravel wave-breaking system.

[0031] The test method for performing a dynamic response test using the suspension tunnel anchor cable failure and progressive collapse dynamic response test device of the present invention comprises the following steps:

[0032] Step 1: Make a test model tube body, install the gyroscope at the center of gravity of the test model tube body, and set a target point on the end cross section of the test model tube body;

[0033] Step 2: Place the test model pipe body into the test water tank, install the anchor system, anchor cable continuous collapse device and other sensor measurement instruments;

[0034] Step 3: After setting the anchor failure threshold tension, turn on the flow and wave making system to create waves and flow, and also turn on the wave breaking system;

[0035] Step 4: Collect and organize the dynamic time domain response data obtained by the sensor measurement instrument after the continuous failure of the anchor cables, and analyze the transient dynamic response of the remaining system of the test model pipe body after the continuous failure of the anchor cables.

[0036] The test method of the present invention can realize instantaneous cable breaking of anchor cables and continuous collapse of suspended tunnels, improve the authenticity and accuracy of data collection, and truly simulate and analyze the mechanical characteristics and motion state change laws of tunnels and anchor cables after anchor cable failure.

[0037] As a preferred embodiment of the present invention, in step three, the failure threshold tension of one or more anchor cables is set to be smaller than the failure threshold tension of other anchor cables. Preferably, the failure threshold tensions of other anchor cables are the same. This test can analyze the change law of the motion state of the tube body after the internal force of the remaining structure is redistributed after the failure of one or more anchor cables, and the time domain dynamic response mechanical characteristics of the continuous collapse of the remaining anchor cables.

[0038] As a preferred solution of the present invention, in step 4, the response intensity coefficient RIF is used to describe the response intensity of the test model pipe body after the anchor cable fails. Where S d is the instantaneous maximum dynamic response of the test model pipe body after the anchor cable fails, and S0 is the instantaneous dynamic response of the test model pipe body before the anchor cable fails. The critical value of continuous collapse after the failure of an anchor cable is determined through simulation tests. When RIF is greater than the critical value, it means that the test model pipe body has experienced continuous collapse after the failure of the anchor cable.

[0039] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0040] (1) The present invention proposes an anchor cable breaking device for simulating the breaking of an anchor cable in a suspended tunnel model. The various components of the device are very small, the structure is simple, and the installation and operation are convenient. The triggering conditions for anchor cable breaking can be self-adjusted, so that the breaking test of different anchor cable tensions can be realized, that is, force control. In addition, the device uses a tension sensor for real-time monitoring, and combines a relay to control the power supply of a de-energized electromagnet to achieve an instantaneous anchor cable breaking effect, thereby improving the authenticity and accuracy of data collection. The anchor cable breaking device can be used repeatedly and has low cost.

[0041] (2) The present invention can achieve the continuous collapse effect of the suspended tunnel by setting up multiple groups of tension sensors and control circuit devices, truly simulate and analyze the transient dynamic response of the remaining system after the continuous failure of the anchor cables, and provide a reference for the design and construction of the suspended tunnel.

[0042] (3) The present invention uses a gyroscope and a non-contact strain displacement measuring device to accurately measure the motion posture of the underwater suspended tunnel model. Among them, the gyroscope can accurately obtain the three rotation time domain responses of the test model tube body, namely pitch, roll and yaw, by measuring the angular velocity of the model tube body; the non-contact strain displacement measuring device can obtain the translation time domain response of the test model tube body, namely the horizontal translation time domain and the vertical translation time domain response. Not only does it not need to consider the complex requirement that the sensor needs to be waterproofed, it is easy to install and operate, and it can also accurately use computer algorithms to solve the translation time domain response of the tube body, solving the problem that the gyroscope cannot accurately measure the translation time domain response. Finally, the response results are graphically displayed on the computer, which has the advantages of intuitive and visible images and high measurement accuracy, and is convenient for better understanding and analysis of the performance of the test model tube body.

[0043] (4) The present invention specifically designs a special model constraint device, which controls the magnitude of the constraint effect through the axial stiffness and torsional stiffness of the six-directional springs, thereby simulating the actual constraint conditions of the test model tube body more realistically and flexibly.

[0044] (5) The present invention extends the anchor cable to the water surface through a pulley, and the tension sensor for measuring the anchor cable tension can be installed on the water surface, converting the underwater measurement of the test model into a mature and high-precision water measurement, without considering the waterproof problem of the sensor and the convenience of installation operation. At the same time, by adjusting the position of the false bottom installation, different anchor cable angle arrangements can be achieved.

[0045] (6) The present invention can change the magnitude of the initial tensile stress of the anchor cable by adjusting the cable tensioner, thereby meeting different initial tensile stresses required by the test.

[0046] (7) The test method described in the present invention can be used to realize instantaneous cable breaking of anchor cables and continuous collapse of suspended tunnels, improve the authenticity and accuracy of data collection, and truly simulate and analyze the mechanical characteristics and motion state changes of suspended tunnels and anchor cables after anchor cable failure.

[0047] (8) The present invention uses the response intensity factor RIF to describe the response intensity of the test model pipe body after the anchor cable fails. The critical value of progressive collapse after an anchor failure is determined through simulation tests. When the RIF is greater than the critical value, it indicates that the test model pipe body undergoes progressive collapse after the anchor failure. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Figure 1 It is a structural schematic diagram of a suspended tunnel anchor cable failure and progressive collapse dynamic response test device described in the present invention.

[0049] Figure 2 It is a three-dimensional schematic diagram of a suspended tunnel anchor cable failure and progressive collapse dynamic response test device described in the present invention.

[0050] Figure 3 yes Figure 2 A partial enlarged schematic diagram of .

[0051] Figure 4 It is a schematic structural diagram of the anchor cable of the present invention in a normal state.

[0052] Figure 5 It is a schematic structural diagram of the anchor cable of the present invention in a broken state.

[0053] Figure 6 is a circuit diagram of the control circuit device of the present invention.

[0054] Figure 7 It is a structural schematic diagram of the restraining device described in the present invention.

[0055] Icons: 1-test model tube, 2-anchor cable, 3-tension sensor, 4-pulley, 5-cable tensioner, 6-false bottom, 7-fixed bracket, 8-de-energized electromagnet, 9-iron block, 10-comparison circuit, 11-non-contact strain displacement measuring device, 12-background paper, 13-target point, 14-gyroscope, 15-wave height meter, 16-flow meter, 17-tension spring, 18-torsion spring, 101-wave and flow making system, 102-wave breaking system. DETAILED DESCRIPTION

[0056] The present invention will be described in detail below in conjunction with the accompanying drawings.

[0057] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0058] Example 1

[0059] like Figure 1-Figure 3 As shown, a suspension tunnel anchor failure and continuous collapse dynamic response test device includes a test water tank, a test model pipe body 1, an anchor system, an anchor continuous collapse device and a sensor measurement instrument.

[0060] The test water tank mainly includes a water tank, a wave and flow making system 101 and a wave breaking system 102 .

[0061] The length of the water tank should be much larger than its cross-sectional size, which can reduce the reflection of waves. The wave-making and flow-generating system 101 is arranged at one end of the test water tank, and the wave-breaking system 102, i.e., a gravel wave-breaking system, is arranged at the other end. The wave-making and flow-generating system 101 can be used to simulate the dynamic response of the suspended tunnel test model under the action of waves and flows. The wave-breaking system 102 is mainly a wave-breaking device made of gravel, which is used to reduce the reflection of oncoming waves, thereby improving the authenticity of the collected data.

[0062] The cross section of the test model tube body 1 is set to be circular, and a white background paper 12 is pasted on one end of the test model tube body 1, and three black characteristic dots, namely, target points 13, are arranged on the background paper 12. Since the background paper 12 is pasted on the cross section of the test model tube body 1, the target points 13 can ensure that they always move in coordination with the cross section of the test model tube body 1 during the measurement process without any movement, so that the movement posture of the target points 13 is consistent with the movement posture of the test model tube body 1.

[0063] The mooring system includes an anchor cable 2, a cable tensioner 5, a pulley 4, a false bottom 6 and a fixed bracket 7 on the water surface. The test model pipe body 1 is suspended in the water by the support of the anchor cable 2. The anchor cable 2 is extended to the fixed bracket 7 on the water surface through the pulley 4 pre-fixed on the false bottom 6, so that the tension sensor 3 for monitoring the tension of the anchor cable 2 can be placed above the water surface, realizing the conversion of underwater measurement into surface measurement, which not only meets the measurement accuracy requirements, but also does not need to consider waterproof measures and the convenience of installation operation. The pulley 4 can slide along the false bottom 6, so as to change the force transmission direction of the anchor cable 2.

[0064] The cable tensioner 5 is installed on the anchor cable 2 . The anchor cable 2 can be adjusted by rotating the cable tensioner 5 , thereby changing the initial tension stress of the anchor cable 2 .

[0065] The anchor cable continuous collapse device includes multiple anchor cable break trigger devices, each anchor cable break trigger device includes a tension sensor 3 and a control circuit device, the tension sensor 3 is installed on the anchor cable 2, and the tension state of the anchor cable 2 is monitored in real time. The tension data can be observed on the sensor digital display instrument, and the tension sensor 3 is externally connected to a control circuit device. The control circuit device includes a power-off type electromagnet 8 and an iron block 9 installed on the anchor cable 2, and the power-off type electromagnet 8 is connected to a comparison circuit 10, and the comparison circuit 10 includes a voltage comparator, a relay K and resistors (R1, R2, R Z , R P ), the device first uses the voltage comparator to realize power off or power on, and then realizes the magnetic or non-magnetic nature of the de-energized electromagnet 8 through the action of the relay K, so that the iron block 9 will be attracted and separated from the de-energized electromagnet 8, and separation indicates that the anchor cable 2 is broken, that is, the control function of cable breaking is realized.

[0066] The tension sensor 3 adopts a resistive strain type tension sensor, which is a sensor composed of a measuring circuit composed of a resistance strain gauge and an elastic sensitive element. When the elastic sensitive element is subjected to external tension, strain will be generated, and the resistance strain gauge attached to the surface will also be strained, and the resistance value will change.

[0067] The circuit structure of the control circuit device, such as Figure 6 As shown, the resistance value of the tension sensor strain gauge is Rz. When a 5V voltage is applied to the Rz and R1 resistors, the voltage at point A is VA. When the tension of the anchor cable 2 increases, the resistance value of the resistor Rz decreases, causing VA to rise. When the tension of the anchor cable 2 reaches a certain set value, the tension value is the set failure threshold tension FTH. R2 and Rp form a voltage divider. Adjusting Rp can change the voltage of VB. The VB value is the threshold voltage set by the comparator, called VTH. Once the tension of the anchor cable 2 exceeds the failure threshold tension FTH, VA>VTH, the comparator outputs a low level, the relay K is energized, the de-energized electromagnet 8 is energized and loses its magnetism, so that the de-energized electromagnet 8 is separated from the iron block 9, thereby achieving the purpose of breaking the anchor cable 2.

[0068] like Figure 4 As shown, the trigger condition for the anchor cable 2 to break is the set failure threshold tension of the anchor cable 2. When the tension does not reach the set value, the relay K cannot start working, the de-energized electromagnet 8 is magnetic, the de-energized electromagnet 8 is attracted to the iron block 9, and the anchor cable 2 is in a normal state. Figure 5 As shown, when the tension reaches the set value, the relay K starts to work, the de-energized electromagnet 8 becomes non-magnetic, and the de-energized electromagnet 8 is separated from the iron block 9, thereby controlling the occurrence of cable breakage.

[0069] The sensing and measuring instruments include a gyroscope 14, a non-contact strain displacement measuring device 11, a wave height meter 15 and a flow meter 16. The gyroscope 14 is installed at the center of gravity of the test model tube body 1. The gyroscope 14 can be used to measure the angular velocity of rotation around the axis, and the rotation angle around the axis can be obtained by deduction. The spatial posture at the center of mass of the tube body is calculated, so that the rotation amount of the suspended tunnel model can be calculated.

[0070] The non-contact strain displacement measuring device 11 includes the above-mentioned background paper 12 and target 13, and at least two cameras, preferably industrial high-speed cameras. The non-contact strain displacement measuring device 11 uses the industrial high-speed camera to perform high-speed sampling on the target 13, and performs a comparison algorithm through the collected image-related points to calculate the displacement and strain distribution on the surface of the target 13.

[0071] Example 2

[0072] like Figure 7 As shown, the difference between this embodiment and embodiment 1 is that the dynamic response test device described in this embodiment further includes a restraining device, the restraining device comprises a tension spring 17 and a torsion spring 18, the tension spring 17 is installed in the lateral swing, longitudinal swing and vertical swing directions of the test model pipe body 1, the tension spring 17 is used to simulate the restraining effect of the adjacent pipe section on the lateral swing, longitudinal swing and vertical swing of the test model pipe body 1, the torsion spring 18 is installed in the roll, pitch and yaw directions of the test model pipe body 1, the torsion spring 18 is used to simulate the restraining effect of the adjacent pipe section on the roll, pitch and yaw of the test model pipe body 1

[0073] Among them, the stiffness of the tension spring 17 and the torsion spring 18 can be determined by numerical simulation, empirical formula, etc. to first determine the segment equivalent stiffness, and then obtain the spring stiffness. For example, the calculation formula for the equivalent stiffness of the suspended tunnel segment is:

[0074]

[0075] In the formula, K i (i=1,2,3,4,5,6) are the equivalent stiffness of the suspended tunnel segment in the six directions of sway, sway, heave, roll, pitch and pitch. i (i=1,2,3,4,5,6) are the masses of the suspended tunnel segments taking into account the additional water masses in each direction of sway, surge, heave, roll, pitch and bow swing. i (i=1, 2, 3, 4, 5, 6) represents the first-order natural vibration period (obtained by numerical simulation) of the suspended tunnel segment in the lateral, longitudinal, heave, roll, pitch and yaw directions, respectively.

[0076] Since the segment model and prototype under study are scaled, the prototype equivalent stiffness value needs to be converted into the model equivalent stiffness value through the similarity ratio.

[0077] Example 3

[0078] This embodiment discloses a method for testing the dynamic response of continuous collapse of a suspended tunnel based on anchor failure, and the test is performed using the suspended tunnel anchor failure and continuous collapse dynamic response test device as described in Embodiment 1 or Embodiment 2, including the following steps:

[0079] Step 1: Make a test model tube body 1, install a gyroscope 14 at the center of gravity of the test model tube body 1, take waterproof measures, and attach a background plate 12 with a target point 13 to the end cross section of the test model tube body 1;

[0080] Step 2: Place the test model pipe body 1 in the test water tank, install the anchor system, anchor cable continuous collapse device and other sensor measurement instruments (wave height meter 15, current meter 16, industrial high-speed camera, etc.);

[0081] Step 3: setting the failure threshold tension of the anchor cables 2, setting the failure threshold tension of one or more anchor cables 2 to be smaller than the failure threshold tension of other anchor cables 2, and setting the failure threshold tension of other anchor cables 2 to be the same, turning on the flow and wave making system 101 to make waves and flow, and also turning on the wave breaking system 102;

[0082] Step 4: Observe the continuous collapse of the remaining anchor cables 2 after one or more anchor cables 2 fail, collect and organize the dynamic time domain response data obtained by the sensing and measuring instruments after the continuous failure of the anchor cables, and analyze the time domain dynamic response of the continuous collapse of the remaining anchor cables of the suspended tunnel after the failure of the anchor cables.

[0083] In step 4, the response severity coefficient RIF is used to describe the response severity of the test model pipe body after the anchor cable fails. Where S d is the instantaneous maximum dynamic response of the test model pipe body after the anchor cable fails, and S0 is the instantaneous dynamic response of the test model pipe body before the anchor cable fails. The critical value of continuous collapse after the failure of a cable is determined through simulation tests. When RIF is greater than the critical value, it means that the test model pipe body will experience continuous collapse after the failure of the cable, otherwise it will not.

[0084] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A test method for dynamic response of anchor failure and progressive collapse of a suspended tunnel, characterized in that: A test device for failure and continuous collapse of anchor cables in a suspended tunnel is used for testing. The test device comprises a test water tank, a test model pipe body, an anchor system and an anchor cable continuous collapse device. The test model pipe body is installed in the test water tank through the anchor system. The anchor system comprises an anchor cable and a cable tensioner. The cable tensioner is installed on the anchor cable. The cable tensioner is used to adjust the anchor cable. The anchor cable continuous collapse device comprises a plurality of anchor cable breaking trigger devices. Each anchor cable breaking trigger device is installed on the anchor cable. The anchor cable breaking trigger device comprises a tension sensor and a control circuit device. The tension sensor is used to monitor the tension of the anchor cable. The control circuit device is connected to the tension sensor. The control circuit device is used to break the anchor cable according to the tension value measured by the tension sensor. The test method comprises the following steps: Step 1: Make a test model tube body, install the gyroscope at the center of gravity of the test model tube body, and set a target point on the end cross section of the test model tube body; Step 2: Place the test model pipe body into the test water tank, install the anchor system, anchor cable continuous collapse device and other sensor measurement instruments; Step 3: After setting the anchor failure threshold tension, turn on the flow and wave making system to create waves and flow, and also turn on the wave breaking system; Step 4: Collect and organize the dynamic time domain response data obtained by the sensor measurement instrument after the continuous failure of the anchor cables, and analyze the transient dynamic response of the remaining system of the test model pipe body after the continuous failure of the anchor cables.

2. The method for testing the dynamic response of anchor failure and progressive collapse of a suspended tunnel according to claim 1 is characterized in that: The step three is to set the failure threshold tension of one or more anchor cables to be smaller than the failure threshold tension of other anchor cables.

3. The method for testing the dynamic response of anchor failure and progressive collapse of a suspended tunnel according to claim 2 is characterized in that: In step 4, the response intensity factor RIF is used to describe the response intensity of the test model pipe body after the anchor cable fails. Where S d is the instantaneous maximum dynamic response of the test model pipe body after the anchor cable fails, S0 is the instantaneous dynamic response of the test model pipe body before the anchor cable fails. When RIF is greater than the critical value, it means that the test model pipe body undergoes continuous collapse after the anchor cable fails.

4. The method for testing the dynamic response of anchor failure and progressive collapse of a suspended tunnel according to claim 1, characterized in that: The control circuit device includes a de-energized electromagnet and an iron block installed on the anchor cable, and the de-energized electromagnet is connected to a comparison circuit, the comparison circuit includes a voltage comparator, a relay and a resistor, and the comparison circuit outputs high and low levels through the voltage comparator to control the opening and closing of the relay, and then controls the magnetism of the de-energized electromagnet, so that the iron block adsorbs or separates the de-energized electromagnet.

5. The method for testing the dynamic response of anchor failure and progressive collapse of a suspended tunnel according to claim 1, characterized in that: It also includes a sensing and measuring instrument, which includes a gyroscope and a non-contact strain displacement measuring device. The gyroscope is installed at the center of gravity of the test model tube body. The non-contact strain displacement measuring device includes at least two cameras and a plurality of target points arranged on the cross section of the test model tube body.

6. The method for testing the dynamic response of anchor failure and progressive collapse of a suspended tunnel according to claim 5, characterized in that: The non-contact strain displacement measuring device further comprises background paper, the background paper is pasted on the cross section of the test model tube body, and the target point is arranged on the background paper.

7. The method for testing the dynamic response of anchor failure and progressive collapse of a suspended tunnel according to claim 5, characterized in that: The number of the target points is 3, and the 3 target points are arranged non-collinearly.

8. The method for testing the dynamic response of anchor failure and progressive collapse of a suspended tunnel according to claim 1, characterized in that: The mooring system also includes a false bottom, a pulley and a fixed bracket, wherein the false bottom is fixed to the bottom of the test water tank, the fixed bracket is fixed above the water surface, the anchor cable passes through the pulley and is connected to the fixed bracket, the pulley can slide along the false bottom, and the tension sensor is installed on the anchor cable above the water surface.

9. The method for testing the dynamic response of anchor failure and progressive collapse of a suspended tunnel according to any one of claims 4 to 8, characterized in that: It also includes a restraint device, which includes a tension spring and a torsion spring. The tension spring is installed in the lateral swing, longitudinal swing and vertical swing directions of the test model pipe body, and the tension spring is used to simulate the restraining effect of adjacent pipe sections on the lateral swing, longitudinal swing and vertical swing of the test model pipe body. The torsion spring is installed in the roll, pitch and yaw directions of the test model pipe body, and the torsion spring is used to simulate the restraining effect of adjacent pipe sections on the roll, pitch and yaw of the test model pipe body.

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