Passive protective net device suitable for tunnel portal slope

Abstract

A passive protective net device suitable for a tunnel portal slope comprises a protective net, a fixing frame, a pull rope, a solar cell panel, a storage battery, an element box, an anchor rod and a short message module and further comprises a control circuit, a detection mechanism, a fixing frame inclination detection circuit and a protective net and pull rope detection circuit. The fixing frame is installed in front of a monitoring area, the lower ends of the two pull ropes are installed on the two anchor rods respectively, the two stretching upper ends are installed at the upper end of the fixing frame, and the protective nets are installed on the two sides of the pull ropes and the rear side of the fixing frame respectively. The storage battery, the short message module, the control circuit, the detection mechanism, the fixing frame inclination detection circuit, the protective net and the pull rope detection circuit are installed in the element box, the solar cell panel is installed on the rear outer side of the element box, and the front side of the element box is installed on the rear side of the fixing frame. The tension springs can play a role in buffering and protecting the protective net, and related personnel can be remotely prompted to go to the site for disposal in a short message mode at the first time when rockfall occurs, the protective net or the pull rope is damaged, and the fixing frame inclines or collapses.

Description

Technical Field

[0001] The utility model relates to the technical field of protective equipment, in particular to a passive protective net device suitable for a tunnel opening slope. Background Art

[0002] Shallow bias tunnel is an important construction method in tunnel engineering. Its design and construction methods have greater flexibility and plasticity than traditional deep tunnel. Specifically, the design of shallow bias tunnel first considers the topography and geomorphology, and uses the bias of geological structure to make the top and bottom of the tunnel not on the same horizontal plane, and then determines the structural form and equipment parameters according to various requirements. Compared with deep tunnel, shallow bias tunnel has the advantages of shallow depth, multiple structural forms, effective use of geological structure bias, and short construction period. Shallow bias tunnel can also greatly save the space used on the ground, and is more flexible in terms of tunnel length, cross-sectional shape, construction method and construction period.

[0003] Although shallow-buried bias-pressure tunnels have the above-mentioned advantages, they are limited by their structure and construction methods and still have the following major technical problems. Due to the special engineering geological conditions, the thickness of the stratum where the tunnel is located is relatively thin, the terrain is asymmetrical on both sides, and the slope stability is poor. Therefore, the slope is very susceptible to construction vibration or precipitation erosion, resulting in the falling of stones or rock spalling on the slope, which seriously threatens the safety of the tunnel entrance. Therefore, in the current actual construction, a passive protection net system is set up under the slope to intercept rolling stones from above. For the existing protection net, when the speed of falling rocks on the slope is high, it has a great impact on the protection net, and when it exceeds its interception limit, due to the poor ductility of the protection net, there is a probability that the protection net and its side end pull rope will break, and then lose the function of intercepting falling rocks, thereby endangering the traffic safety below the slope. More importantly, the currently used protective net system cannot prompt the relevant personnel who are not on site to go to the site in time to deal with the situation when the protective net or the rope is damaged, the fixed frame tilts or collapses, or when rolling stones occur. This increases the probability of safety accidents due to the inability to repair the relevant equipment and eliminate the relevant hidden dangers in time. In summary, it is particularly necessary to provide a protective net device that not only has the functions of an ordinary protective net, but also can monitor the presence of rolling stones and the related performance of the protective net equipment in real time, and can promptly prompt the remote relevant personnel to go to the site to deal with the situation by SMS in the event of falling rocks and damage to the protective net equipment. Utility Model Content

[0004] In order to overcome the drawbacks of the existing protective net equipment used in shallow biased tunnels due to structural limitations as described in the background, the utility model provides a passive protective net device suitable for the slope of the tunnel entrance, which is powered by solar panels and batteries in coordination with the joint action of relevant mechanisms, thereby saving electricity and reducing the cost of laying lines. When working, it can monitor whether there is rockfall in relevant positions as comprehensively as possible. In the event of rockfall, damage to the protective net or rope, tilt or collapse of the fixed frame, it can remotely prompt relevant personnel to go to the scene for disposal via text messages at the first time, thereby reducing the probability of accidents and achieving better safety effects.

[0005] The technical solution adopted by the utility model to solve its technical problems is:

[0006] A passive protective net device suitable for the slope of a tunnel entrance, comprising a protective net, a fixed frame, a pull rope, a solar panel, a storage battery, a component box, an anchor rod, and a text message module, characterized in that it also comprises a control circuit, a detection mechanism, a fixed frame tilt detection circuit, a protective net and a pull rope detection circuit; there are at least two anchor rods and pull ropes, the lower part of the fixed frame is at the front end of the monitoring area, the lower ends of the two pull ropes are respectively mounted on the two anchor rods, the two stretched upper ends are mounted on the upper end of the fixed frame, and the protective net is respectively mounted on both sides of the pull rope and the rear side of the fixed frame; the storage battery, the text message module, the control circuit, the trigger circuit of the detection mechanism, the fixed frame tilt detection circuit, the protective net The net and rope detection circuit are installed in the component box, the solar cell panel is installed at the rear outer end of the component box, and the front end of the component box is installed on the rear end of the fixing frame; the solar cell panel and the battery, the SMS module, the control circuit, the trigger circuit of the detection mechanism, the fixing frame tilt detection circuit, the protective net and the rope detection circuit are electrically connected to the power input end; the trigger output end of the control circuit is electrically connected to the trigger signal input end of the detection mechanism, the signal output end of the fixing frame tilt detection circuit, the protective net and the rope detection circuit is electrically connected to the control signal input end of the detection mechanism, and the signal output end of the detection mechanism is electrically connected to the signal input end of the SMS module.

[0007] Furthermore, the detection mechanism includes a motor reduction device, a microwave detection module, and a trigger circuit. The lower end of the microwave detection module is installed on the rotating shaft of the motor reduction device. There is an opening on the rear end of the component box, and the detection head of the microwave detection module is located in the opening.

[0008] Furthermore, the trigger circuit includes an electrically connected adjustable resistor, a resistor, and a transistor, and is connected to a microwave detection module, the signal output end of the microwave detection module is connected to one end of the adjustable resistor, the other end of the adjustable resistor is connected to one end of the first resistor and the other end of the second resistor, the other end of the second resistor is connected to the base of the transistor, and the other end of the first resistor is connected to the emitter of the transistor and the negative power input end of the microwave detection module.

[0009] Furthermore, the control circuit includes two electrically connected time-controlled switches, and two ends of power inputs of the two time-controlled switches are respectively connected.

[0010] Furthermore, the fixing frame tilt detection circuit includes a resistor and a mercury switch, the universal mercury switch is installed on the fixing frame, and one end of the resistor is connected to one end of the mercury switch.

[0011] Furthermore, the protective net and pull rope detection circuit includes an electrically connected resistor, a transistor and a wire. The wire is straightened and installed between the protective net and the two pull ropes after being wrapped around multiple times with a distance between the upper and lower parts. The head end of the wire is connected to one end of the first resistor, the tail end of the wire is connected to one end of the second resistor, the other end of the second resistor is connected to the base of the first transistor, the collector of the first transistor is connected to the other end of the first resistor and the base of the second transistor, and the emitters of the two transistors are connected.

[0012] Furthermore, each pull rope is divided into two sections, and a tension spring is installed in series between the two sections of the pull rope.

[0013] Compared with the prior art, the present invention has the following beneficial effects: (1) the present invention uses solar panels and batteries to supply power, which saves electricity and reduces the cost of laying lines. The tension spring of the pull rope can play a role in buffering and protecting the protective net (when falling rocks collide with the protective net, the probability of the pull rope breaking is reduced as much as possible due to the buffering effect); (2) the control circuit, detection mechanism, fixed frame tilt detection circuit, protective net and pull rope detection circuit can monitor whether there is falling rocks in the relevant positions as comprehensively as possible when working. In the first time when falling rocks, the protective net or pull rope is damaged, or the fixed frame tilts or collapses, the relevant personnel can be remotely prompted to go to the scene for disposal by SMS, thereby reducing the probability of accidents and achieving better safety effects. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0015] Figure 1 It is a schematic diagram of the overall and partial enlarged structure of the utility model.

[0016] Figure 2 , 3 It is a partial enlarged structural schematic diagram of the utility model.

[0017] Figure 4 This is a circuit diagram of the utility model. DETAILED DESCRIPTION

[0018] Figure 1 , 2As shown in Figures 3 and 4, a passive protection net device suitable for the slope of a tunnel entrance comprises a protection net 1, a fixing frame 2, a pull rope 3, a solar panel G1, a battery G2, a component box 4, an anchor rod 5, and a text message module W2. It also has a control circuit 6, a detection mechanism, a fixing frame tilt detection circuit 7, a protection net and a pull rope detection circuit 8; there are at least two anchor rods 5 and pull ropes 3, the lower end of the fixing frame 2 is vertically installed on a concrete foundation pile 12 under the ground of the monitoring area, and the lower ends of the two anchor rods 5 are deeply buried under the ground at both sides of the foundation pile 12, and the two anchor rods 5 are installed on the ground at both sides of the foundation pile 12. The lower ends of the pull ropes 3 are fixedly mounted on the two anchor rods 5 respectively, the upper ends of the two pull ropes 3 are fixedly mounted on both sides of the upper end of the fixing frame 2, and the two sides and the middle front side of the protective net 1 are respectively mounted on both sides of the pull rope 3 and the rear side end of the fixing frame 2; the battery G2, SMS module W2, control circuit 6, fixing frame inclination detection circuit 7, protective net and pull rope detection circuit 8, and trigger circuit 9 of the detection mechanism are mounted on the circuit board inside the component box 4, the solar cell panel G1 is mounted on the rear outer side end of the component box 4, and the front side end of the component box 4 is bolted to the upper part of the rear side end of the fixing frame 2.

[0019] Figure 1 , 2As shown in Figures 3 and 4, the detection mechanism includes a motor reduction device M1, a microwave detector W1, a trigger circuit 9, and push-button normally closed power switches D and D1. The lower end of the microwave detection module W1 is horizontally fixedly installed on the rotating shaft of the motor reduction device M1. A laterally distributed rectangular opening 41 is provided in the upper middle of the rear end of the component box 4 (to ensure that the detection head of the microwave detection module W1 can detect the relevant area at nearly 180 degrees). The detection head of the microwave detection module W1 is located outside the rear side end of the opening 41. A baffle 10 is laterally welded to the lower end of the rotating shaft of the motor reduction device M1. A fixing seat 11 is respectively welded to the outside of the middle of both sides of the upper end of the shell of the motor reduction device M1. The shells of the two power switches D and D1 are respectively glued to the rear ends of the two fixing seats 11, and the buttons of the power switches D and D1 face the rear side (the baffle 10 is located at the rear side ends of the buttons of the power switches D and D1). The trigger circuit includes an adjustable resistor RP1, resistors R1 and R2, and a transistor Q1 connected via circuit board wiring, and is connected to a microwave detection module W1 via a wire, a signal output terminal 3 pin of the microwave detection module W1 is connected to one end of the adjustable resistor RP1, one end of the adjustable resistor RP1 is connected to one end of the first resistor R1 and the other end of the second resistor R2, the other end of the second resistor R2 is connected to the base of the transistor Q1, the other end of the first resistor R1 is connected to the emitter of the transistor Q1 and the negative power input terminal 2 pin of the microwave detection module W1. The control circuit includes two-way time-controlled switches W3 and W connected via circuit board wiring, the power input terminals 1 and 2 of the two-way time-controlled switches W3 and W are respectively connected, and the positive power output terminals 3 pins of the two-way time-controlled switches W and W3 are respectively connected to one end of two power switches D and D1 of the trigger circuit via wires. The fixed frame tilt detection circuit includes a resistor R4 and a mercury switch GH1. The mercury switch GH1 is vertically installed alone in a shell, and the lower end of the shell is horizontally installed outside the upper end of the fixed frame 2. The mercury switch is a universal mercury switch, and the mercury of the mercury switch GH1 is located at the lower end of its shell and the two contact contacts are located at the upper end of the shell. One end of the resistor R4 is connected to one end of the mercury switch GH1. The protection net and the pull rope detection circuit includes resistors R3 and R5, transistors Q2 and Q3 and thin enameled wire X. The enameled wire X is straightened and installed between the rear end of the protection net 1 and the two pull ropes 3 with a distance of 4 cm between the upper and lower parts (the gap between the enameled wire X and the protection net 1 is wound and fixed), the head end of the enameled wire X is connected to one end of the first resistor R5, the tail end of the enameled wire X is connected to one end of the second resistor R3, the other end of the second resistor R3 is connected to the base of the first transistor Q1, the collector of the first transistor Q1 is connected to the other end of the first resistor R5 and the base of the second transistor Q2, and the emitters of the two transistors Q2 and Q3 are connected. Each pull rope 3 is divided into two sections, and a tension spring 31 is fixedly installed in series between the two sections of the pull rope (the upper and lower ends of the tension spring are fixedly connected to the lower end of the upper pull rope and the upper end of the lower pull rope).

[0020] Figure 1 , 2As shown in Figures 3 and 4, the two poles of the solar panel G1 and the battery G2 are connected by wires, and are connected in series with the power input terminals 1 and 2 of the SMS module W2, the power input terminals 1 and 2 of the control circuit, the power input terminals 1 and 2 of the time switch W3, the power input terminals 1 and 2 of the detection mechanism, the power input terminals 1 and 2 of the microwave detection module W1, the other end of the mercury switch GH1 at the power input terminal of the fixed frame tilt detection circuit, one end of the resistor R5 at the power input terminal of the protection net and the pull rope detection circuit, and the emitter of the transistor Q2. The 3rd pin of the time switch W is connected in series with the power switch D, the 4th pin of the time switch W and the 3rd pin of the time switch W3 are connected in series with the power switch D1, the 4th pin of the time switch W3, and the positive and negative and negative and positive power input terminals of the motor reduction device M1 are connected by wires. The other end of the resistor R4 at the signal output end of the fixed frame tilt detection circuit is connected to the base of the transistor Q1 through a wire, and the collector of the transistor Q3 at the signal output end of the protection net and pull rope detection circuit, the collector of the transistor Q1 at the signal output end of the detection mechanism and the signal input end pin 3 of the SMS module W2 are connected through a wire.

[0021] Figure 1 , 2As shown in Figures 3 and 4, after the installation of the new model, the protective net is located in the area prone to geological disasters on the front side of the slope of the tunnel entrance (a few meters or so will suffice, such as an area prone to rockfall). The solar panel G1 of the new model is usually exposed to light to generate electricity to charge the battery G2, which ensures that the new model can be used all day on rainy days and at night, saving electricity and reducing the cost of setting up power supply lines; the tension spring 31 of the pull rope can play a buffering role (when falling rocks collide with the protective net 1, the tension spring 31 has a buffering effect, which minimizes the probability of the pull rope 3 breaking). The power output by the battery G2 enters the control circuit, the detection mechanism, the fixed frame tilt detection circuit, the protective net and the pull rope detection circuit, and the power input end of the SMS module W2. After the control circuit is powered on, the 3rd and 4th pins of the time-controlled switches W and W3 will cyclically output power for 6 seconds to the positive and negative and / or negative and positive power input terminals of the motor reduction device M1 (for example, the 3rd and 4th pins of the time-controlled switch W will first output power for 6 seconds, and then the 3rd and 4th pins of the time-controlled switch W3 will output power for 6 seconds, and the above process will be continuously cycled). Subsequently, the shaft of the motor reduction device M1 will drive the microwave detection module W1 to rotate clockwise and counterclockwise along the opening 41 (close to 180 degrees), and the microwave detection module W1 will monitor whether there is rockfall in the front area. In actual situations, when the shaft drives the baffle 10 to rotate to the left or right stop point, the front side end or the rear side end of the baffle will press the button of the power switch D or D1 respectively, and the internal contact of the power switch D or D1 will be open. Since the 3rd pin of the time switch W is connected in series through the power switch D, the 4th pin of the time switch W and the 3rd pin of the time switch W3 are connected in series through the power switch D1, and the 4th pin of the time switch W3 are connected to the positive and negative and negative and positive and negative power input terminals of the motor reduction device M1 respectively through wires, when the shaft drives the microwave detection module W3 to rotate to the left or right stop point, the motor reduction device M1 will lose power and not work, preventing the motor reduction device M1 from rotating to the left or right angle without control, causing the device to fail to work normally (without affecting the reverse power supply of the power input terminal of the motor reduction device M1). When the microwave detection module W1 is powered on and working, if there is no falling rock rolling at the front end of its detection head (for example, about 7 meters), the 3rd pin of the microwave detection module W1 will not output a high level, and the corresponding SMS module W2 will not send SMS. When the microwave detection module W1 is working and a rock falls and rolls at the front end of its detection head, the pin 3 of the microwave detection module W1 will output a high level. The high level is divided by the adjustable resistor RP1 and the resistor R1, and the resistor R2 reduces the voltage and limits the current (higher than 0.7V) to enter the base of the transistor Q1. The transistor Q1 is turned on and the collector outputs a low level to enter the signal input terminal pin 3 of the SMS module W2. The SMS module W2 then sends out the SMS stored inside.

[0022] Figure 1 , 2As shown in Figures 3 and 4, when there is no falling rock that knocks down the fixed pole 2 or causes it to tilt, the internal contact of the mercury switch GH1 will not close. In this way, the transistor Q1 will not be turned on, and the corresponding SMS module W2 will not send SMS. When the falling rock knocks down the fixed pole 2 or causes it to tilt, the internal contact of the mercury switch GH1 will be closed, and the positive electrode of the 12V power supply will enter the base of the transistor Q1 through the resistor R4 to reduce the voltage and limit the current. The transistor Q1 is turned on and the collector outputs a low level to enter the signal input terminal 3 of the SMS module W2, and the SMS module W2 will then send out the internally stored SMS. In the protective net and pull rope detection circuit, when there is no falling rock that hits the protective net 1 or the pull rope 3 to cause the protective net or the pull rope 3 to be damaged or broken, the enameled wire will not break, and the positive electrode of the 12V power supply will enter the base of the transistor Q2 through the enameled wire X through the resistor R3 to reduce the voltage and limit the current. The transistor Q2 is turned on and its collector outputs a low level to enter the base of the transistor Q3. The transistor Q3 will not be turned on, and the corresponding SMS module W2 will not send SMS. When a falling rock collides with the protective net 1 or the pull rope 3, causing the protective net or the pull rope 3 to be damaged or broken, the enameled wire X will break, and the positive electrode of the 12V power supply will no longer enter the base of the transistor Q2 through the enameled wire X. The collector of the transistor Q2 will no longer output a low level and enter the base of the transistor Q3. The transistor Q3 will obtain a suitable forward bias voltage through the resistor R5 to reduce the voltage and limit the current, and the collector will output a low level and enter the signal input terminal 3 of the SMS module W2. The SMS module W3 will then send out the SMS stored inside.

[0023] Figure 1 , 2 As shown in Figures 3 and 4, through the above, the new type can monitor whether there is rockfall in relevant positions as comprehensively as possible when working. In the first time when rockfall occurs, the protective net or rope is damaged, or the fixed frame is tilted or collapsed, it can remotely prompt relevant personnel to go to the scene for disposal by SMS, thereby reducing the probability of accidents and achieving better safety effects. Figure 4As shown, the motor reduction mechanism M1 is a finished product of a coaxial motor gear reducer with a power of 10W (5 revolutions per minute); the time control switch W3, W is a finished product of a time control switch of model KG136, which has two power input terminals, two power output terminals, and seven setting buttons. The seven setting buttons can be operated respectively to set the time for the power output terminal to output power; the resistance values ​​of resistors R1, R2, R3, R4, and R5 are 4.7K, 10K, 100K, 100K, and 200K respectively; the transistors Q1, Q2, and Q3 are NPN transistors of model 9013; the power switches D and D1 are self-reset button type normally closed power switches; the solar panel G1 model is 12V, 20W; the battery G2 is a lithium battery of specification 12V / 50Ah; The adjustable resistor RP1 has a resistance of 470K (adjusted to 21.5K in this embodiment. The larger the resistance value is adjusted, the greater the voltage division is. Then, when the distance between the detection heads of the subsequent rockfall interval microwave detection module W1 is closer, the transistor Q1 will be turned on, that is, the detection threshold of this embodiment is relatively close; when the resistance value is adjusted to a smaller value, the smaller the voltage division is. Then, when the distance between the detection heads of the subsequent rockfall interval microwave detection module W1 is larger, the transistor Q1 will be turned on, that is, the detection threshold of this embodiment is relatively large); the microwave detection module W1 is a finished product of a microwave detection module of model TWH9251, which has two power input terminals and a signal output terminal. The detection distance of the detection head is adjustable from 2 to 7 meters. After actual installation, the front end of the detection head is aligned with the detection area; the SMS module W2 is a GSM The SMS alarm module of 800, the finished SMS alarm module has two power input terminals 1 and 2, and signal input ports 3-8. After a low-level signal is input to each signal input port, the finished SMS alarm module will send a text message via the wireless mobile network. The SMS alarm module stores text messages. This embodiment stores "Rolling stones occur on site". After a low-level signal is input to pin 3 of the signal input port of the SMS alarm module, the SMS alarm module can send a text message.

[0024] The above shows and describes the basic principles and main features of the utility model and the advantages of the utility model. For those skilled in the art, it is obvious that the utility model is limited to the details of the above exemplary embodiments, and the utility model can be implemented in other specific forms without departing from the spirit or basic features of the utility model. Therefore, no matter from which point of view, the embodiments should be regarded as exemplary and non-restrictive. The scope of the utility model is defined by the attached claims rather than the above description, and it is intended that all changes that fall within the meaning and scope of the equivalent elements of the claims are included in the utility model.

[0025] In addition, it should be understood that although the present specification is described according to the implementation mode, the implementation mode does not only include an independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in the embodiments can also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A passive protection net device suitable for tunnel entrance slope, comprising a protection net, a fixing frame, a pull rope, a solar panel, a battery, a component box, an anchor rod, and a text message module, characterized in that: It also has a control circuit, a detection mechanism, a fixed frame tilt detection circuit, a protective net and a pull rope detection circuit; there are at least two anchor rods and pull ropes, the lower part of the fixed frame is at the front end of the monitoring area, the lower ends of the two pull ropes are respectively installed on the two anchor rods, the upper ends of the two pull ropes are installed on the upper end of the fixed frame, and the protective nets are respectively installed on both sides of the pull ropes and the rear side of the fixed frame; the battery, the SMS module, the control circuit, the trigger circuit of the detection mechanism, the fixed frame tilt detection circuit, the protective net and the pull rope detection circuit are installed in the component box, the solar cell panel is installed at the rear outer end of the component box, and the front end of the component box is installed on the rear end of the fixed frame; the solar cell panel and the battery, the SMS module, the control circuit, the trigger circuit of the detection mechanism, the fixed frame tilt detection circuit, the protective net and the pull rope detection circuit are electrically connected to the power input end; the trigger output end of the control circuit is electrically connected to the trigger signal input end of the detection mechanism, the signal output end of the fixed frame tilt detection circuit, the protective net and the pull rope detection circuit is electrically connected to the control signal input end of the detection mechanism, and the signal output end of the detection mechanism is electrically connected to the signal input end of the SMS module.

2. A passive protection net device suitable for tunnel entrance slope according to claim 1, characterized in that: The detection mechanism includes a motor reduction device, a microwave detection module, and a trigger circuit. The lower end of the microwave detection module is installed on the rotating shaft of the motor reduction device. There is an opening on the rear end of the component box, and the detection head of the microwave detection module is located in the opening.

3. A passive protection net device suitable for tunnel entrance slope according to claim 1, characterized in that: The trigger circuit includes an electrically connected adjustable resistor, a resistor, and a transistor, and is connected to a microwave detection module. The signal output end of the microwave detection module is connected to one end of the adjustable resistor, the other end of the adjustable resistor is connected to one end of the first resistor and the other end of the second resistor, the other end of the second resistor is connected to the base of the transistor, and the other end of the first resistor is connected to the emitter of the transistor and the negative power input end of the microwave detection module.

4. A passive protection net device suitable for tunnel entrance slope according to claim 1, characterized in that: The control circuit comprises two electrically connected time-controlled switches, and two ends of power input of the two time-controlled switches are connected respectively.

5. A passive protection net device suitable for tunnel entrance slope according to claim 1, characterized in that: The fixed frame tilt detection circuit comprises a resistor and a mercury switch. The universal mercury switch is installed on the fixed frame, and one end of the resistor is connected to one end of the mercury switch.

6. A passive protection net device suitable for tunnel entrance slope according to claim 1, characterized in that: The protective net and pull rope detection circuit includes an electrically connected resistor, a transistor and a wire. The wire is straightened and installed between the protective net and the two pull ropes with multiple turns at a distance from top to bottom. The head end of the wire is connected to one end of the first resistor, the tail end of the wire is connected to one end of the second resistor, the other end of the second resistor is connected to the base of the first transistor, the collector of the first transistor is connected to the other end of the first resistor and the base of the second transistor, and the emitters of the two transistors are connected.

7. A passive protection net device suitable for tunnel entrance slope according to claim 1, characterized in that: Each pull rope is divided into two sections, and a tension spring is installed in series between the two sections of the pull rope.

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