A system and method for monitoring slope slippage in an open cut coal mine

Abstract

This invention discloses a landslide monitoring system and method for open-pit coal mine slopes. It is a BOTDR-based open-pit coal mine slope disaster monitoring system and method. The BOTDR-based system includes a distributed optical fiber sensing system, which comprises a sensing and sensor network module and a data signal processing module. The sensing and sensor network module senses soil and rock deformation, obtains strain signals of the deformation via a strain optical fiber, and transmits the strain signals using a communication optical fiber. The data signal processing module receives, controls, and analyzes the strain signals transmitted via the strain optical fiber. This invention enables long-distance, large-scale, spatiotemporal continuous internal monitoring of soil and rock deformation in open-pit coal mine slopes under complex environments, providing long-term and effective monitoring and real-time acquisition of soil and rock deformation monitoring data.

Description

Technical Field

[0001] This invention belongs to the field of fiber optic sensing and monitoring technology, specifically relating to a landslide monitoring system and method for open-pit coal mine slopes. Background Technology

[0002] In open-pit coal mining, slopes are primarily constructed using artificial excavation. As mining operations continue, the slopes continue to develop. Slope engineering plays a crucial role in open-pit coal mine construction. Various natural and non-natural factors can easily cause landslides and collapses during open-pit coal mining, endangering lives and causing property damage. Therefore, monitoring the stability of open-pit coal mine slopes is of paramount importance.

[0003] Currently, the main equipment for landslide monitoring includes total stations, inclinometers, and slope radar. These devices are all based on surface and fixed-point monitoring methods and cannot monitor the interior of the slope, thus posing a risk of monitoring failure or malfunction. Due to the limitations of existing monitoring methods, they cannot accurately monitor the overall stability of the slope. Therefore, there is an urgent need to design a high-resolution, low-cost monitoring method capable of monitoring both the interior and surface of the slope, thereby improving monitoring effectiveness. Summary of the Invention

[0004] Based on the technical problems existing in the prior art, the present invention provides a landslide monitoring system and method for open-pit coal mine slopes. It is a BOTDR-based open-pit coal mine slope disaster monitoring system and method, which solves the problems of large error, high cost, limitation to point and surface testing, and inability to conduct distributed and internal sensing and monitoring of soil and rock masses in the prior art.

[0005] To address the aforementioned technical problems, according to a first aspect of the present invention, an open-pit coal mine slope landslide monitoring system is provided, comprising a distributed optical fiber sensing system. The distributed optical fiber sensing system includes a sensing and sensing network module and a data signal processing module. The sensing and sensing network module is used to sense the deformation of the soil and rock mass, obtain strain signals of the deformation through a strain optical fiber, and transmit the strain signals using a communication optical fiber. The data signal processing module is used to receive, control, and analyze the strain signals transmitted through the strain optical fiber. The sensing and sensing network module includes the slope's boundary soil and rock mass, the slope's sloping soil and rock mass, iron or aluminum alloy hoops, anchor bolts, strain optical cables, and communication optical cables. Trenches of different depths are excavated on the surface of the boundary soil and rock mass. Threaded anchor bolts of a set length are inserted at equal intervals at the bottom of the trenches. The strain optical cables are fixed to the anchor bolts by iron or aluminum alloy hoops and the anchor bolt lugs. The slope's sloping soil and rock mass are connected to the boundary soil and rock mass, forming a slope surface at a certain angle to the horizontal plane. The communication optical cable is connected to the strain optical cable and is used to transmit strain signals to the data signal processing module.

[0006] Preferably, in the sensing and sensing network module of the open-pit coal mine slope landslide monitoring system, anchor rods of a set length are directly inserted into the slope slope soil and rock mass, strain optical cables are fixed to the anchor rod lugs of the anchor rods by iron hoops or aluminum alloy hoops, strain optical cables pass through PVC sleeves, and the strain optical cables are connected to communication optical cables, which are then connected to optical switch controllers.

[0007] Furthermore, the data signal processing module includes a relay, an optical fiber patch cord, a data line, a BOTDR demodulator, an OTDR analyzer, and a display terminal. The relay is connected to the display terminal and the optical switch controller via data lines. The optical switch controller is connected to the BOTDR demodulator, the OTDR analyzer, and the optical fiber patch cord. The BOTDR demodulator and the OTDR analyzer are connected to the relay via data lines.

[0008] Preferably, the strain optical cable and the communication optical cable are connected by optical cable fusion splicing machine, the optical loss at the splice point is less than 0.1dB, and a polyurethane heat shrink tubing is inserted at the splice point.

[0009] Preferably, the trench is located near the upper edge of the slope's rock and soil mass; a thin layer of fine sand is laid at the bottom of the trench, and anchor bolts are inserted at intervals of 2m-15m at the bottom of the trench. The anchor bolts are threaded, with a length of 50cm-150cm and a diameter of 1cm-3cm, and are notched circular connectors with an anchor lug at the top. An iron or aluminum alloy hoop is attached to the anchor lug, and the anchor bolt body is threaded. The diameter of the circular connector is between 3cm and 8cm. The spacing of the anchor bolts is calculated based on the slope safety factor, using the following formula: S = (2πrτ) / (F) S *γ*H); In the formula, S is the spacing between anchor bolts, r is the diameter of the anchor bolt, τ is the bond strength of the slope rock and soil, γ is the weight of the slope rock and soil, H is the slope height of the slope rock and soil, and F S This is the slope safety factor.

[0010] Preferably, the excavation of the border rock and soil body involves trenches less than 50cm deep. At the bottom of the trench, threaded carbon steel anchors with a length of 100cm and a diameter of 2cm are inserted. The distance between the anchors is 10m. The inner wall of the anchor lug with a diameter of 5cm at the top of each anchor is provided with arranged iron or aluminum alloy hoops. These hoops fix the strain gauge cable to the inner wall of the anchor lug, keeping the anchor lug in contact with the ground. The strain gauge cable is taut between the anchors. A small amount of fine sand is used to fill the strain gauge cable and anchor lug, thus filling the trench with sandy mudstone. The pre-tension strain of the strain gauge cable and the anchoring stress of the anchor (2) satisfy the following formula: T = k * αS; In the formula, T is the pre-tension strain, α is the anchoring stress, k is the coupling coefficient, k∈[0.8,1], and S is the spacing of the anchor rods (2).

[0011] Furthermore, threaded anchor rods with a diameter of 2 cm and a length of 100 cm are directly inserted into the slope's rock and soil mass. The anchor rods are laid in a U-shape with a distance of 10 m between them. Each anchor rod has an anchor lug, and strain gauge optical cables are arranged inside the anchor lug. Iron hoops or aluminum alloy hoops fix the strain gauge optical cables to the inner wall of the anchor lug, keeping the anchor lug in contact with the ground. The strain gauge optical cables are taut between the anchor rods, and the angle of the strain gauge optical cable at the bending corner is greater than 90°.

[0012] According to a second aspect of the technical solution of the present invention, a method for monitoring landslides on open-pit coal mine slopes is provided, which is implemented using the above-mentioned open-pit coal mine slope landslide monitoring system, and includes the following steps: Step S1: Locating trenches in the edge rock and soil of the open-pit coal mine slope. Trenches of different depths are excavated at the edge of the edge rock and soil to monitor the stress changes inside the open-pit coal mine slope. Step S2: Excavate the trench according to the trench location determined in Step S1: During trench construction, the trench depth is less than 50cm and the trench width is less than 30cm; during the trench excavation process, the excavated sandy mudstone soil is placed next to the trench for backfilling; after the trench is formed, a thin layer of fine sand is laid at the bottom of the trench. Step S3: Insert threaded carbon steel anchor rods into the bottom of the trench along the slope and rock mass. Bind the strain gauge cable to the anchor rods and lay it on the fine sand. Then cover the laid strain gauge cable with a thicker layer of fine sand in the trench. After that, lay the strain gauge cable on the thicker layer of fine sand. Then backfill the excavated sandy mudstone soil onto the surface of the fine sand in the trench. Repeat this process to lay the strain gauge cable in a U-shape with the ends connected. Strain optical cables are guided from the top of the trench in the slope edge rock and soil mass to the slope slope rock and soil mass; strain optical cables are laid directly on the surface of the slope slope rock and soil mass, so that the strain optical cables laid on the surface of the slope slope rock and soil mass are laid in a U-shape with the beginning and end connected; threaded carbon steel anchor rods are directly inserted into the surface of the slope slope rock and soil mass, and the anchor rod lugs at the top of the anchor rods are connected to the strain optical cables through iron hoops or aluminum alloy hoops to keep the strain optical cables connected between the anchor rods in a taut state. Step S4: On the lower side of the slope rock and soil, the strain optical cable is connected to the communication optical cable. The strain optical cable end is fused to the communication optical cable beginning using an optical cable fusion splicer.

[0013] Furthermore, the open-pit coal mine slope landslide monitoring method further includes the following steps: Step S5: Laying the communication optical cable. The steel wire rope and the communication optical cable are tied together with cable ties. The steel wire rope and the communication optical cable are passed through the hole at the top of the cement pole together. The end of the communication optical cable is connected to the optical switch controller. Step S6: Connect the data signal processing module. Transmit the strain signal of the strain optical cable transmitted by the communication optical cable to the data signal processing module. The relay in the data signal processing module is connected to the display terminal and the optical switch controller. The optical switch controller is connected to the OTDR analyzer and the BOTDR demodulator through the optical cable jumper. The OTDR analyzer and the BOTDR demodulator are connected to the relay.

[0014] Preferably, the open-pit coal mine slope landslide monitoring method further includes the following steps: Step S7: The distributed optical cable sensing and monitoring system performs monitoring range analysis, measures the detection distance of the laid communication optical cable and strain optical cable, and detects the connectivity of the laid strain optical cable and communication optical cable; controls the relay to enable the optical switch controller to connect the BOTDR demodulator, so that the entire optical signal can be detected along the entire laid strain optical cable, and controls the display terminal to modulate the optical signal.

[0015] Compared with existing technologies, the open-pit coal mine slope landslide monitoring system and method of the present invention have the following beneficial effects: 1. This invention provides long-distance, spatiotemporal continuous, and internal monitoring for open-pit coal mine slopes. It solves the problem that traditional monitoring equipment struggles to conduct long-term, stable internal monitoring of coal mine slopes under complex conditions such as prolonged manual operations and natural rainfall. This invention utilizes distributed optical fiber sensing technology to achieve long-term monitoring for over five years even in complex natural environments.

[0016] 2. This invention enables large-scale real-time distributed monitoring of open-pit coal mine slopes, effectively solving the limitations of existing monitoring methods such as point-based measurement, surface measurement only, susceptibility to interference from external factors, and inability to acquire monitoring data in real time. Distributed optical fiber sensing technology can achieve large-scale, distributed, and real-time internal monitoring.

[0017] 3. This invention is the first to obtain slope displacement monitoring data through distributed optical cable monitoring, realizing the assessment of slope stability in open-pit coal mines.

[0018] 4. This invention involves inserting anchor bolts at the bottom of the trench, with the anchor bolt lugs tightly against the ground surface of the rock and soil mass, keeping the strain optical cable taut between the anchor bolts, and fixing the strain optical cable to the anchor bolt lugs with iron hoops or aluminum alloy hoops. Sand is then laid on top to cover the rock and soil mass, enabling monitoring of the interior of the slope. At the location where the strain optical cable is laid on the slope, the anchor bolts allow the cable to bend at angles greater than 90°, preventing the cable from being squeezed, broken, or knotted, thus better protecting the strain optical cable and improving the acquisition of strain data.

[0019] 5. By using distributed optical fiber sensing technology, this invention can perform long-distance, large-scale, spatiotemporal continuous, and internal long-term effective monitoring of rock and soil deformation on open-pit coal mine slopes. It can also monitor rock deformation under complex environmental conditions and acquire real-time monitoring data of slope rock and soil deformation. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the open-pit coal mine slope landslide monitoring system according to the present invention; Figure 2 This is a schematic diagram of the arrangement of strain gauge optical cables on the slope surface; Figure 3 This is a schematic diagram of the anchor bolt structure; Figure 4 This is a cross-sectional schematic diagram of the internal structure of the strain gauge optical cable; Figure 5 This is a cross-sectional schematic diagram of the internal structure of a communication optical cable.

[0021] Figure 6 This is a schematic diagram of the test results of the distributed strain optical cable strain data of the present invention.

[0022] The following are the reference numerals in the attached figures: 1. Strain gauge fiber optic cable; 2. Anchor bolt; 3. Communication fiber optic cable; 4. Cement pole; 5. Fixed valve; 6. Trench; 7. Junction box; 8. Fine sandy soil; 9. Sandy mudstone soil; 10. BOTDR demodulator; 11. Optical switch controller; 12. Display terminal; 13. Polyether flame-retardant polyurethane sheath; 14. Aramid reinforcement; 15. Spiral armor tube; 16. Fiber optic cable sheath; 17. Outer sheath; 18. Tightly wrapped fiber; 19. Steel cable; 20. Iron hoop or aluminum alloy hoop; 21. Thread; 22. Anchor bolt lug; 23. Border rock and soil; 24. Slope rock and soil; 25. Relay; 26. Fiber optic cable patch cord; 27. Data cable; 28. OTDR analyzer. Detailed Implementation

[0023] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0024] To better illustrate this embodiment, some components in the accompanying drawings may be omitted, enlarged, or reduced, and do not represent the actual dimensions of the product. The technical solution of the present invention will be further described below with reference to the accompanying drawings and embodiments.

[0025] This invention discloses a landslide monitoring system for open-pit coal mine slopes. It is a BOTDR-based open-pit coal mine slope disaster monitoring system, comprising a sensing and sensor network module and a data signal processing module. The sensing and sensor network module includes the slope's edge rock and soil mass 23, the slope's sloping rock and soil mass 24, iron or aluminum alloy hoops 20, anchor bolts 2, strain gauge optical cables 1, and communication optical cables 3. A trench 6 is excavated on the surface of the edge rock and soil mass 23, and anchor bolts 2 are inserted into the bottom of the trench 6, connected by iron or aluminum alloy hoops. The alloy hoop 20 fixes the strain optical cable 1 to the anchor lug 22 of the anchor rod 2. The slope rock and soil mass 24 is directly inserted into the anchor rod 2. The strain optical cable 1 is fixed to the anchor lug 22 of the anchor rod 2 by the iron hoop or aluminum alloy hoop 20. The strain optical cable 1 is connected to the communication optical cable 3, and the communication optical cable 3 is connected to the optical switch controller 11. The data signal processing module includes a relay 25, an optical cable jumper 26, a data line 27, a BOTDR demodulator 10, an OTDR analyzer 28, and a display terminal 12. The relay 25 is connected to the display terminal 12 and the data line of the optical switch controller 11. The optical switch controller 11 is connected to the optical cable jumper 26 of the BOTDR demodulator 10 and the OTDR analyzer 28. The BOTDR demodulator 10 and the OTDR analyzer 28 are connected to the data line 27 of the relay 25.

[0026] The BOTDR, or Brillouin Optical Time Domain Reflectometer, is a distributed fiber optic sensing device based on the Brillouin scattering effect. It achieves real-time monitoring of temperature and strain by measuring the Brillouin frequency shift distribution along the fiber. The BOTDR utilizes the linear relationship between the change in power or frequency shift of spontaneously scattered Brillouin light in the fiber and changes in temperature and strain. It emits probe pulses using a laser, collects the scattered signals, analyzes the frequency shift data, and ultimately locates the temperature or strain information at various points along the fiber. The Brillouin optical time domain reflectometer technology used in this invention has advantages such as resistance to electromagnetic interference, single-end access, and a wide monitoring range, and can be applied to fields such as power transmission line icing early warning and underground engineering monitoring.

[0027] An OTDR (optical time-domain reflectometer) is an instrument that analyzes measurement curves to understand several properties of optical fibers, such as uniformity, defects, breaks, and splice coupling. OTDRs are based on the principles of backscattering and Fresnel reflection of light, using the backscattered light generated when light propagates in the fiber to obtain attenuation information. They can be used to measure fiber attenuation, splice loss, locate fiber fault points, and understand the loss distribution along the fiber's length.

[0028] Furthermore, the strain optical cables 1 are connected to each other and to the communication optical cable 3 by optical cable fusion splicing. The optical loss at the splice point is less than 0.1dB, and a polyurethane heat shrink tubing is inserted at the splice point. A trench 6 less than 50cm deep is excavated in the border rock and soil mass 23. Anchor rods 2 with threads 21, each 100cm long and 2cm in diameter, are inserted into the bottom of the trench 6. The anchor rods 2 are made of carbon steel. The distance between anchor rods 2 is 10m. The top inner wall of the anchor rod lug 22, with a diameter of 5cm at the top of each anchor rod 2, is provided with arranged iron or aluminum alloy hoops 20. The iron or aluminum alloy hoops 20 fix the strain optical cables 1 to the inner wall of the anchor rod lug 22, keeping the anchor rod lug 22 in contact with the ground, and the strain optical cables 1 are taut between the anchor rods 2. A small amount of fine sand is used to fill the strain optical cables 1 and the anchor rod lug 22, and the sandy mudstone soil mass 9 is used to fill the trench 6. In another embodiment, the slope slope rock and soil 24 is directly inserted with a threaded anchor 2, which is 100cm long and 2cm in diameter. The anchor 2 is laid in a U-shape and the distance between the anchor 2 is 10m. The anchor 2 is provided with anchor lugs 22. The strain optical cable 1 is arranged in the anchor lugs 22. The iron hoop or aluminum alloy hoop 20 fixes the strain optical cable 1 to the inner wall of the anchor lug 22, keeping the anchor lug 22 in contact with the slope rock and soil 23 or the slope slope rock and soil 24. The strain optical cable 1 is taut between the anchor 2. The angle of the strain optical cable 1 at the bending corner of the strain optical cable is greater than 90°.

[0029] The specific embodiments of the present invention will now be described with reference to the accompanying drawings. Figure 1As shown, the open-pit coal mine slope landslide monitoring system of the present invention includes a sensing and sensor network module and a data signal processing module. The sensing and sensor network module is used to sense the deformation of the rock and soil mass, obtain the strain signal of the rock and soil mass deformation through the strain optical cable 1, and realize the transmission of the strain signal using the communication optical cable 3. The data signal processing module is used to receive, control and analyze the strain signal transmitted by the communication optical cable 3. Further, the sensing and sensor network module includes a boundary rock and soil mass 23, a slope rock and soil mass 24, an anchor 2, a strain optical cable 1 and a communication optical cable 3; the boundary rock and soil mass 23 is the main body of the accumulated soil or the top surface of the coal pile, which is basically on the same plane as the horizontal plane; the slope rock and soil mass 24 is connected to the boundary rock and soil mass 23 and forms a slope surface with a certain angle to the horizontal plane; the anchor 2 is inserted into the boundary rock and soil mass 23 and / or the slope rock and soil mass 24 to fix the strain optical cable 1; the strain optical cable 1 is used to sense the deformation or change of the slope rock and soil mass 24. The communication optical cable 3 is connected to the strain optical cable 1 via the junction box 7, and is used to transmit the deformation signal of the slope rock and soil 24 sensed by the strain optical cable 1 to the data signal processing module.

[0030] In one embodiment, such as Figures 1-3As shown, a trench 6 with a depth of less than 50cm is excavated on the surface of the slope rock and soil 23. Preferably, the trench 6 is close to the upper edge of the slope rock and soil 24. A thin layer of fine sand 8 is laid at the bottom of the trench 6. Anchor rods 2 are inserted at any interval between 2m and 15m at the bottom of the trench 6. The anchor rods 2 are carbon steel anchor rods with threads 21 with any length between 50cm and 150cm and any diameter between 1cm and 3cm. An anchor rod ears 22 are provided at the top of the anchor rods 2. The anchor rod ears 22 are circular connectors with notches. Iron hoops or aluminum alloy hoops 20 are provided on the anchor rod ears 22. The anchor rod body is provided with threads 21. The diameter of the circular connector is any value between 3cm and 8cm. The strain gauge fiber optic cable 1 passes through the circular connector of the anchor bolt lug 22 and is fixed to the anchor bolt lug 22 via an iron hoop or aluminum alloy hoop 20, keeping the strain gauge fiber optic cable 1 connected between the anchor bolts 2 taut. A thick layer of fine sand soil 8 is placed in the trench 6, and then sandy mudstone soil 9 is placed on top of the fine sand soil 8 in the trench 6. Further, the same strain gauge fiber optic cable 1 is guided to the slope rock and soil 24, and an anchor bolt 2 with a thread 21 of any length between 50cm and 150cm and any diameter between 1cm and 3cm is directly inserted into the surface of the slope rock and soil 24. Similarly, the strain gauge fiber optic cable 1 is fixed to the anchor bolt lug 22 of the anchor bolt 2 via an iron hoop or aluminum alloy hoop 20, keeping the strain gauge fiber optic cable 1 taut. Optimally, the strain optical cable 1 installed in the slope rock and soil mass 24 and the border rock and soil mass 23 is a single strain optical cable 1, so that there is no attenuation or distortion of the sensing signal; and the strain optical cable 1 installed in the border rock and soil mass 23 extends deep into the sandy mudstone soil mass 9 of the border rock and soil mass 23 to maximize the sensing of any deformation or loosening of the border rock and soil mass 23.

[0031] like Figure 1 As shown, strain gauge optical cable 1 is connected to one end of communication optical cable 3 via junction box 7. Communication optical cable 3 is fixed to the top of multiple cement poles 4 using fixing valve 5. The other end of communication optical cable 3 is connected to optical switch controller 11. In a preferred embodiment, strain gauge optical cable 1 is arranged in a zigzag pattern within the slope rock and soil mass 24 and the edge rock and soil mass 23, preferably using a continuous "U"-shaped arrangement structure. The spacing between the U-shaped arms of the "U"-shaped arrangement structure is no greater than 2 meters, preferably no greater than 50 centimeters. In a preferred embodiment, strain gauge optical cable 1 is a 9000m long armored type; communication optical cable 3 is 1800m long and is fixed to the top of a 15-meter-high cement pole 4, ultimately connecting to optical switch controller 11.

[0032] In another preferred embodiment, a trench 6 with a depth of 10-35cm is excavated on the surface of the border rock and soil 23. Anchor rods 2 with any spacing of 8m-12m are inserted into the bottom of the trench 6. The anchor rods 2 are anchor rods with threads 21 with any length of 80cm-120cm and any diameter of 1.5cm-2.5cm. The diameter of the circular connector of the anchor rod lug 22 is any value of 4cm to 6cm.

[0033] In another preferred embodiment, anchor rods 2, spaced 10m apart, are inserted into the bottom of the trench 6. Each anchor rod 2 is 100cm long, 2cm in diameter, and threaded 21. Anchor rod lugs 22, 5cm in diameter at the top of each anchor rod 2, are connected to the strain gauge optical cable 1 via iron or aluminum alloy hoops 20, keeping the strain gauge optical cable 1 connected between the anchor rods 2 taut. The strain gauge optical cable 1 is connected end-to-end to the communication optical cable 3. A fixing valve 5 secures the communication optical cable 3 to the top of a 15-meter-high concrete pole 4. Finally, the communication optical cable 3 is connected to the optical switch controller 11. The strain gauge optical cable 1 is 9000m long; the communication optical cable 3 is 1800m long. The data signal processing module includes a relay 25, an optical cable patch cord 26, a data line 27, a BOTDR demodulator 10, an OTDR analyzer 28, and a display terminal 12. The relay 25 controls the reception of demodulated data from the BOTDR demodulator 10 and / or the OTDR analyzer 28, and simultaneously controls the transmission of demodulated data to the display terminal 12. Furthermore, it controls the optical switch controller to connect the optical path to the BOTDR demodulator 10 and / or the OTDR analyzer 28. The relay's function or purpose is described as follows: The optical cable patch cord 26 transmits the strain signal from the communication optical cable 3 to the BOTDR demodulator 10 and the OTDR analyzer 28. The data line 27 transmits data from the OTDR analyzer 28 or the BOTDR demodulator 10 to a computer. The BOTDR demodulator 10 controls the basic parameters of its internal modules and demodulates the strain signal of the soil and rock mass. The OTDR analyzer 28 measures the loss of the strain optical cable 1. The display terminal 12 visualizes, monitors, and analyzes the acquired data.

[0034] In one embodiment, the OTDR analyzer acquires optical cable link loss data α in real time. L The data is transmitted to a BOTDR demodulator for strain error compensation. The compensation formula is as follows: ε c =εr*(1 α L / α max ); In the formula, εr is the original strain value, α max Maximum loss, ε c This is the compensation value.

[0035] In one embodiment, relay 25 is connected to data line 27 of display terminal 12 and optical switch controller 11, optical switch controller 11 is connected to BOTDR demodulator 10, OTDR analyzer 28 and optical cable patch cord 26, and BOTDR demodulator 10 and OTDR analyzer 28 are connected to data line 27 of relay 25.

[0036] In the open-pit coal mine slope landslide monitoring system of the present invention, 100cm anchor rods 2 are directly inserted into the slope rock and soil mass 24. The anchor rods 2 are laid in a U-shape arrangement, with a distance of 10m between them. They are made of threaded steel and have anchor lugs 22. Strain gauge optical cables 1 are arranged in the anchor lugs 22. The top inner wall of the anchor lugs 22 is provided with arranged iron hoops or aluminum alloy hoops 20, which fix the strain gauge optical cables 1 on the inner wall of the anchor lugs 22. The angle of the strain gauge optical cable 1 at the bending corner is greater than 90°. The strain gauge optical cable 1 is armored, with a tight-packed optical cable core, a stranded steel cable outer layer, and a medium-density polyether flame-retardant polyurethane sheath. The outer diameter is 5.0±0.2mm, and the laying length is 9000m. Communication optical cable 3 is armored, with a core of tight-packed optical cable, an outer layer of aramid, and a sheath of polyether flame-retardant polyurethane. Its outer diameter is 3.0±0.1mm, and its laying length is 1800m.

[0037] like Figure 2 As shown, the strain optical cable 1 is arranged in a U-shape on the slope rock and soil. 100cm anchor rods 2 are directly inserted into the slope rock and soil 24 at 10m intervals. This allows for overall monitoring of the deformation of the slope rock and soil in both horizontal and vertical directions, which is beneficial for understanding the micro-dynamic process of the deformation of the slope rock and soil 24. The angle of the strain optical cable 1 at the bending corner is greater than 90°. The strain optical cable 1 achieves long-distance signal transmission at the cost of relatively low optical loss.

[0038] like Figure 3 As shown, anchor rod 2 is 100cm long and 2cm in diameter, made of carbon steel, with threads 21 engraved on its surface and an anchor lug 22 at one end. This anchor rod structure has low manufacturing cost, high modulus, and can achieve good coupling with the soil and rock mass and strain-resistant optical cable 1. However, in some cases, the combination of axial, bending, and / or shear forces may lead to failure of the fixing structure. Nevertheless, this structure can bear a large main load. The spacing of the anchor rods 2 is calculated based on the slope safety factor, using the following formula: S = (2πrτ) / (F) S *γ*H); In the formula, S is the spacing between anchor bolts, r is the diameter of the anchor bolt, τ is the bond strength of the slope rock and soil, γ is the weight of the slope rock and soil, H is the slope height of the slope rock and soil, and F S This is the slope safety factor.

[0039] like Figure 4 The diagram shows a cross-sectional view of the internal structure of the strain gauge optical cable 1. The strain gauge optical cable 1 is an armored strain sensing optical cable with a multi-layered composite structure design. From the inside out, it consists of an optical cable sheath 16, a spiral armor tube 15, an aramid reinforcement 14, and a polyether flame-retardant polyurethane sheath 13. The optical cable sheath 16 adopts a wrapped-type stress sensing optical cable structure. The spiral armor tube 15 is a flexible tube made of stainless steel, possessing strong flexibility. Under certain conditions, bending cannot exceed the radius, and it cannot be stretched even under strong tension. Even with lateral pressure, it remains very robust under vertical pressure. Utilizing these characteristics, the fragile optical fiber and sensor can be reliably protected after vertical pressure, impact, welding, repeated bending, and lateral pressure. The aramid reinforcement 14 uses a spiral stranded steel cable reinforcement layer, and the polyether flame-retardant polyurethane sheath 13 uses a medium-density polyether flame-retardant polyurethane sheath. The uniform transmission of stress field is achieved through the mechanical coupling of the strain-strength optical cable 1 with the reinforcing layer consisting of the optical cable sheath 16, the spiral armor tube 15, and the aramid reinforcement 14, and the polyether flame-retardant polyurethane sheath 13. The strain amplification effect of the reinforcing layer structure enhances sensing sensitivity, while the elastic modulus matching of the medium-density polyether flame-retardant polyurethane sheath achieves a balance between mechanical protection and stress transmission. The pre-tension strain of the strain-strength optical cable and the anchoring stress of the anchor rod (2) satisfy the following formula: T = k * αS; In the formula, T is the pre-tension strain, α is the anchoring stress, k is the coupling coefficient, k∈[0.8,1], and S is the spacing of the anchor rods (2).

[0040] like Figure 5 As shown, the communication optical cable 3 is also made of a multi-layer composite structure. From the inside out, the communication optical cable 3 consists of a tight-buffered fiber 18, a steel cable 19, and an outer sheath 17. The tight-buffered fiber 18 is a tight-buffered optical cable, and the steel cable 19 is a spiral-stranded steel cable reinforcement layer. The outer sheath 17 is a polyethylene sheath, which is lightweight, has a wide operating temperature range, and can be used for temporary and rapid wiring and repeated deployment and retraction in the field and complex environments. Figure 6 As shown, Figure 6 The horizontal axis represents the optical cable distance, and the vertical axis represents strain (frequency shift). This invention uses three types of optical cables: communication optical cables, strain optical cables 1 in the border rock and soil mass 23, and strain optical cables 1 within the slope of the inclined rock and soil mass 24. All strain optical cables 1 can be distributed sensing optical cables, i.e., distributed strain optical cables. Figure 6In the analysis of the frequency shift results of strain optical cable 1 in the slope rock and soil mass 23 and the slope rock and soil mass 24, it can be seen that comparing the data from December 31, 2024, January 18, 2025, and February 18, 2025, the frequency shift of strain optical cable 1 at some locations increases significantly over time, indicating that strain optical cable 1 at these locations experiences significant strain, mainly due to deformation of the rock and soil mass. This shift result demonstrates that distributed sensing technology can monitor the strain state of the slope in real time.

[0041] According to another aspect of the present invention, a method for monitoring landslides on open-pit coal mine slopes is provided, specifically including the following steps: Step S1: Locate the trench 6 of the edge rock and soil body 23 of the open-pit coal mine slope. Excavate trenches 6 of different depths at the edge of the edge rock and soil body 23. Use the trenches 6 to monitor the stress changes inside the open-pit coal mine slope.

[0042] Step S2: Excavate trench 6 according to the location of trench 6 determined in step S1: During the construction of trench 6, the depth of trench 6 is less than 50cm and the width of trench 6 is less than 30cm; During the excavation of trench 6, the excavated sandy mudstone soil 9 is placed next to trench 6 for backfilling trench 6; After trench 6 is formed, a thin layer of fine sand soil 8 is laid at the bottom of trench 6. The depth of trench 6 is less than 50cm and the width of trench 6 is 20cm; During the excavation of trench 6, the sandy mudstone soil 9 is placed next to trench 6 for backfilling trench 6; After trench 6 is formed, a thin layer of fine sand soil 8 is laid at the bottom of trench 6.

[0043] Step S3: Insert an anchor rod 2 with thread 21 into the bottom of the trench 6 of the slope edge rock and soil 23, bind the strain optical cable 1 to the anchor rod 2 and lay it on the fine sand soil 8, and then cover the laid strain optical cable 1 with a thicker layer of fine sand soil 8 in the trench 6; then lay the strain optical cable 1 on the thicker layer of fine sand soil 8, and then backfill the excavated sandy mudstone soil 9 to cover the surface of the fine sand soil 8 in the trench 6. Repeat this process to lay the strain optical cable 1 so that the strain optical cable 1 laid in the trench 6 is laid in a U-shape with the beginning and end connected. Strain optical cable 1 is guided from the top of the trench 6 of the slope slope rock and soil 23 to the slope slope rock and soil 24; strain optical cable 1 is directly laid on the surface of the slope slope rock and soil 24, so that the strain optical cable 1 laid on the surface of the slope slope rock and soil 24 is laid in a U-shape with the beginning and end connected; anchor rod 2 with thread 21 is directly inserted into the surface of the slope slope rock and soil 24, and the anchor rod ear 22 at the top of the anchor rod 2 is connected to the strain optical cable 1 through iron hoop or aluminum alloy hoop 20, so that the strain optical cable 1 connected between the anchor rods 2 is kept in a taut state. In a preferred embodiment, anchor rods 2, spaced 10m apart, are inserted at the bottom of the trench 6. The anchor rods 2 are 100cm long and 2cm in diameter, made of carbon steel with thread. The anchor rod ears 22, with a diameter of 5cm at the top of the anchor rods 2, are connected to the strain optical cable 1 by iron hoops or aluminum alloy hoops 20, keeping the strain optical cable 1 connected between the anchor rods 2 in a taut state. A thick layer of fine sand 8 is placed in the trench 6, and then sandy mudstone 9 is placed on the surface of the fine sand 8 in the trench 6. The strain optical cable 1 is led out to the slope rock and soil 24. Anchor rods 2, with threads 21 and a length of 100cm and a diameter of 2cm, are directly inserted into the surface of the slope rock and soil 24. The strain optical cable 1 is fixed to the anchor rod ears 22 of the anchor rods 2 by iron hoops or aluminum alloy hoops 20, keeping the strain optical cable 1 in a taut state. Specifically, anchor rods 2 with threads 21, each 100cm long and 2cm in diameter, are directly inserted into the slope rock and soil 24. The anchor rods 2 are laid in a U-shape, with a distance of 10m between them. Strain gauge optical cables 1 are arranged inside the anchor rod ears 22. Iron hoops or aluminum alloy hoops 20 fix the strain gauge optical cables 1 to the inner wall of the anchor rod ears 22. The angle of the strain gauge optical cables 1 at the corners is greater than 90°. The strain gauge optical cables 1 are 9000m long. Step S4: On the lower side of the slope slope rock and soil 24, the strain gauge optical cable 1 is connected to the communication optical cable 3. A fiber optic fusion splicer is used to splice the end of the strain gauge optical cable 1 to the beginning of the communication optical cable 3. Specifically, the strain gauge optical cable 1 is spliced ​​to the communication optical cable 3 using a fiber optic fusion splicer. Before splicing, the protective layers of both the strain gauge optical cable 1 and the communication optical cable 3 are removed using three-pronged fiber strippers to expose the bare fiber cores. The fiber cores are wiped with alcohol, and the fiber cores of both the strain gauge optical cable 1 and the communication optical cable 3 are placed in the splicing area of ​​the fiber optic fusion splicer. After splicing, the quality of the splice point is checked, and the optical loss at the fiber core splice point is controlled to be approximately 0.1 dB. The splice point is then spliced ​​using heat shrink tubing and placed in the slot of the junction box 7 for protection. The junction box 7 is then placed in the meter box for protection.

[0044] Further steps include S5, laying the communication optical cable 3, binding the steel wire rope and the communication optical cable 3 together with cable ties, passing the steel wire rope and the communication optical cable 3 together through the hole at the top of the cement pole 4, and connecting the end of the communication optical cable 3 to the optical switch controller 11; the communication optical cable 3 is 1800m long. Step S6: Connect the data signal processing module. Transmit the strain signal of strain optical cable 1 transmitted by communication optical cable 3 to the data signal processing module. The relay 25 in the data signal processing module is connected to the display terminal 12 and the optical switch controller 11. The optical switch controller 11 is connected to the OTDR analyzer 28 and the BOTDR demodulator 10 through the optical cable jumper 26. The OTDR analyzer 28 and the BOTDR demodulator 10 are connected to the relay 25.

[0045] Step S7: The distributed optical cable sensing and monitoring system analyzes the monitoring range, measures the detection distance of the laid communication optical cable 3 and strain optical cable 1, and detects the connectivity of the laid strain optical cable 1 and communication optical cable 3; controls the relay 25 to enable the optical switch controller 11 to connect the BOTDR demodulator 10, so that the entire optical signal is detected along the entire laid optical cable, and controls the display terminal 12 to modulate the optical signal. Step S7 further includes step S71: controlling the laser pulse width parameter through the display terminal 12, specifically controlling the parameters of the BOTDR demodulator 10 through the display terminal 12 so that the pulse width of the laser output by the BOTDR demodulator 10 is greater than or equal to 60ns; the laser beam modulated by the BOTDR demodulator 10 is transmitted to the optical switch controller 11 through the optical fiber patch cord 26, and then transmitted to the strain optical cable 1 via the communication optical cable 3.

[0046] Step S72: Control the EDFA (Erb-doped Fiber Amplifier) ​​parameters via display terminal 12, setting the EDFA's receiving current to 280mA and the transmitting current to 200mA. Under these parameter settings, the laser beam of strain gauge 1 is very stable and no distortion occurs during transmission. The EDFA is connected to the BOTDR demodulator 10.

[0047] Step S8: The distributed optical cable sensing and monitoring system performs data analysis and spatial positioning. After the signal modulation of the erbium-doped fiber amplifier is completed, the strain data of the strain cable 1 is scanned once using a BOTDR data demodulator while keeping the signal modulation parameters of the erbium-doped fiber amplifier unchanged. The strain signal corresponding to the detection length of the strain cable 1 in the current operating environment is obtained. Based on the laying parameters of the strain cable 1 and the corresponding data of the strain signal, the position of the strain data corresponding to the strain cable 1 in the slope edge rock and soil 23 and the strain cable 1 in the slope slope rock and soil 24 is calibrated and recorded as the original standard reference data. In the monitoring of step S8, since the measurement time interval is short, the changes of the communication optical cable 3 with external factors are generally not considered. Further, the strain optical cable 1 is buried in the soil, and data changes are monitored continuously for 24 hours. If the strain value of the strain optical cable 1 does not change, the strain change caused by temperature can be ignored. In this step, the positioning formula for the spatial distance of the optical cable based on the strain value is: position distance = extraction coefficient × A meters, where A is preferably 0.1021. The laser beam modulated by the BOTDR demodulator 10 is transmitted to the optical switch controller 11 via the fiber optic patch cord 26, and then transmitted to the strain optical cable 1 via the communication optical cable 3. The output end of the BOTDR demodulator 10 is connected to the communication optical cable 3. The position calculated from the connection end of the optical switch controller 11 is the starting point of 0 meters, and the length of the optical cable extending along the communication optical cable 3 and the strain optical cable 1 is the position distance. Parameter A is a fixed setting parameter of the data signal processing module. Once the data signal processing module is determined, the value of parameter A is determined. Similarly, when the data signal processing module changes, the value of parameter A changes accordingly. Since the measurement results can send a maximum of 16,384 data points at a time, with each data point spaced 0.1 meters apart (0.1021 meters to be precise), that is, 16,384 × 0.1 = 1,638.4 meters = 1.6384 kilometers. If the measurement distance is greater than 1.6384 kilometers, and the data points are still spaced 0.1 meters apart, the number of data points sent at once would exceed 16,384, which is too much for the device to store and transmit. Therefore, 8 data points are extracted to output 1 point, with an extraction coefficient of 8. The maximum measurement length can reach 1.6384 × 8 = 13.1072 kilometers, which exceeds 10 kilometers.

[0048] Based on the signal information measured by the strain optical cable 1 at a certain location, it is used as the basic standard signal; when the signal measured by the strain optical cable 1 at that location changes relative to the basic standard signal, it is determined that the rock and soil mass at that location has slipped or moved.

[0049] Furthermore, in the absence of landslides in the slope's rock and soil, the strain values ​​of strain-sensitive optical cable 1 are continuously monitored for a fixed duration (e.g., 3 months), and their average value is used as the original standard reference data.

[0050] Step S9: Judgment of slope landslide monitoring results. If the variation of the monitoring strain optical cable 1 data at a certain moment is within 1% compared with the original standard reference data, the slope slope rock and soil mass is considered to be stable. If the variation of the monitoring strain optical cable 1 data at a certain moment is greater than 1% but less than 5% compared with the original standard reference data, the slope slope rock and soil mass is considered to be likely to landslide, which is a precursor to landslide. If the variation of the monitoring strain optical cable 1 data at a certain moment is greater than 5% but less than 15% compared with the original standard reference data, the slope slope rock and soil mass is considered to have experienced a minor landslide, and the slope slope rock and soil mass should be reinforced. If the data from monitoring strain cable 1 at a certain moment differs from the original standard reference data by more than 15% but less than 25%, a small landslide is considered to have occurred on the slope, and a landslide warning should be issued. If the data from monitoring strain cable 1 at a certain moment differs from the original standard reference data by more than 25% but less than 50%, a medium-sized landslide is considered to have occurred on the slope, and a landslide contingency plan should be implemented immediately. If the data from monitoring strain cable 1 at a certain moment differs from the original standard reference data by more than 50%, a large landslide is considered to have occurred on the slope, and post-landslide solutions should be initiated immediately. If the data from monitoring strain cable 1 at a certain moment differs from the original standard reference data by more than 400%, a collapse is considered to have occurred on the slope, and production equipment near the slope should be removed immediately and personnel should evacuate.

[0051] Furthermore, the strain data of the strained optical cable is continuously monitored for changes, and early warnings are issued in a timely manner.

[0052] The above methods enable the monitoring of artificial slopes in open-pit coal mines, thereby facilitating the assessment of potential hazards. Compared to traditional monitoring methods, open-pit coal mine landslide monitoring technology offers advantages such as small size, long-term durability, resistance to electromagnetic interference, long-distance and wide-range signal transmission, and continuous spatial sensing. Distributed optical fiber sensors can be integrated with slope reinforcements such as anchor bolts. The deformation of the soil and rock mass causes deformation in the reinforcement, which is then transmitted to the optical fiber sensors. These sensors function similarly to the nervous system, capturing a large amount of information in real time to assess the health of the landslide. This technology not only enables dynamic monitoring of the entire process of slope instability occurrence, development, and disaster formation, but also maintains the sensitivity and connectivity of the sensing optical path throughout the monitoring process, demonstrating its feasibility in slope engineering monitoring.

[0053] In summary, this invention utilizes distributed optical fiber sensing technology to enable long-distance, large-scale, spatiotemporally continuous, and internal long-term effective monitoring of rock and soil deformation on open-pit coal mine slopes. It can also monitor rock deformation under complex environmental conditions and acquire real-time monitoring data on slope rock and soil deformation.

[0054] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. For those skilled in the art, other variations or modifications can be made based on the foregoing description. It is neither necessary nor possible to exhaustively describe all possible implementations. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. An open cut coal mine slope landslide monitoring system characterised in that, It includes a distributed optical fiber sensing system, which includes a sensing and sensing network module and a data signal processing module. The sensing and sensing network module is used to sense the deformation of the rock and soil, obtain the strain signal of the rock and soil deformation through the strain optical fiber (1), and realize the transmission of the strain signal using the communication optical fiber (3). The data signal processing module is used to receive, control and analyze the strain signal transmitted by the strain optical fiber (1). The sensing and sensing network module includes the slope edge rock and soil (23), the slope slope rock and soil (24), iron or aluminum alloy hoops (20), anchor bolts (2), strain optical cable (1) and communication optical cable (3). Trenches (6) of different depths are excavated on the surface of the edge rock and soil (23). Anchor bolts (2) with threads (21) of a set length are inserted at equal intervals at the bottom of the trenches (6). The strain optical cable (1) is fixed by the iron or aluminum alloy hoops (20) and the anchor bolt ears (22) of the anchor bolts (2). The slope slope rock and soil (24) is connected to the edge rock and soil (23) and forms a slope surface with a certain angle to the horizontal plane. The communication optical cable (3) is connected to the strain optical cable (1) and is used to transmit the strain signal to the data signal processing module.

2. The open cut coal mine slope landslide monitoring system according to claim 1, characterised in that, In the sensing and sensing network module, the slope slope rock and soil (24) is directly inserted into the anchor rod (2) of a set length. The strain optical cable (1) is fixed to the anchor rod ear (22) of the anchor rod (2) by iron hoop or aluminum alloy hoop (20). The strain optical cable (1) passes through the PVC sleeve. The strain optical cable (1) is connected to the communication optical cable (3). The communication optical cable (3) is connected to the optical switch controller (11).

3. The open-pit coal mine slope landslide monitoring system according to claim 1, characterized in that, The data signal processing module includes a relay (25), an optical cable patch cord (26), a data line (27), a BOTDR demodulator (10), an OTDR analyzer (28), and a display terminal (12). The relay (25) is connected to the display terminal (12) and the data line (27) of the optical switch controller (11). The optical switch controller (11) is connected to the BOTDR demodulator (10), the OTDR analyzer (28), and the optical cable patch cord (26). The BOTDR demodulator (10) and the OTDR analyzer (28) are connected to the relay (25) and the data line (27).

4. The open-pit coal mine slope landslide monitoring system according to claim 2, characterized in that, The strain optical cable (1) and the communication optical cable (3) are connected by optical cable fusion splicing machine. The optical loss at the splice point is less than 0.1dB, and a polyurethane heat shrink tube is inserted at the splice point.

5. The open-pit coal mine slope landslide monitoring system according to claim 1, characterized in that, The trench (6) is close to the upper edge of the slope rock and soil (24); a thin layer of fine sand (8) is laid at the bottom of the trench (6); anchor rods (2) are inserted at any distance between 2m and 15m at the bottom of the trench (6); the anchor rods (2) are threaded (21) with any length between 50cm and 150cm and any diameter between 1cm and 3cm; the top of the anchor rod (2) is provided with an anchor lug (22); the anchor lug (22) is a round connector with a notch; an iron hoop or aluminum alloy hoop (20) is provided on the anchor lug (22); the anchor rod (2) is threaded (21) on its body; the diameter of the round connector is any value between 3cm and 8cm. The spacing of the anchor bolts (2) is calculated based on the slope safety factor, and the calculation formula is as follows: S = (2πrτ) / (F S *γ*H); In the formula, S is the layout spacing, r is the anchor rod diameter, τ is the bonding strength of the inclined rock-soil body, γ is the weight of the inclined rock-soil body, H is the slope height of the inclined rock-soil body, F S is the slope safety factor.

6. The open-pit coal mine slope landslide monitoring system according to claim 5, characterized in that, The border rock and soil body (23) is excavated with a trench (6) less than 50cm deep. An anchor rod (2) with a length of 100cm and a diameter of 2cm with threads (21) is inserted into the bottom of the trench (6). The distance between the anchor rods (2) is 10m. The top inner wall of the anchor rod ear (22) with a diameter of 5cm at the top of the anchor rod (2) is provided with arranged iron hoops or aluminum alloy hoops (20). The iron hoops or aluminum alloy hoops (20) fix the strain optical cable (1) on the inner wall of the anchor rod ear (22), keep the anchor rod ear (22) in contact with the ground, and tighten the strain optical cable (1) between the anchor rods (2). A small amount of fine sand is used to fill the strain optical cable (1) and the anchor rod ear (22) to fill the trench (6) with sandy mudstone soil body (9).

7. The open-pit coal mine slope landslide monitoring system according to claim 5, characterized in that, An anchor rod (2) with a thread (21) and a diameter of 2cm is directly inserted into the slope rock and soil (24). The anchor rod (2) is laid in a U-shape and the distance between the anchor rods (2) is 10m. The anchor rod (2) is provided with anchor rod ears (22). The strain optical cable (1) is arranged in the anchor rod ears (22). The iron hoop or aluminum alloy hoop (20) fixes the strain optical cable (1) on the inner wall of the anchor rod ear (22) to keep the anchor rod ear (22) in contact with the ground. The strain optical cable (1) between the anchor rods (2) is taut. The angle of the strain optical cable (1) at the bending corner of the strain optical cable (1) is greater than 90°. The pre-tension strain of the strained optical cable (1) and the anchoring stress of the anchor rod (2) satisfy the following formula: T = k * αS; In the formula, T is the pre-tension strain, α is the anchoring stress, k is the coupling coefficient, k∈[0.8,1], and S is the spacing of the anchor rods (2).

8. A method for monitoring landslides on open-pit coal mine slopes, using the method described in claim 1. The open-pit coal mine slope landslide monitoring system described in any one of the 7 descriptions is characterized by: Specifically, the following steps are included: Step S1: Locate the trench (6) in the edge rock and soil mass (23) of the open-pit coal mine slope. Excavate trenches (6) of different depths at the edge of the edge rock and soil mass (23) and use the trenches (6) to monitor the stress changes inside the open-pit coal mine slope. Step S2: Excavate the trench (6) according to the location of the trench (6) determined in step S1: During the construction of the trench (6), the depth of the trench (6) is less than 50cm and the width of the trench (6) is less than 30cm; During the excavation of the trench (6), the excavated sandy mudstone soil (9) is placed next to the trench (6) for backfilling the trench (6); After the trench (6) is formed, a thin layer of fine sand soil (8) is laid at the bottom of the trench (6); Step S3: Insert a threaded (21) anchor rod (2) into the bottom of the trench (6) of the slope edge rock and soil (23), bind the strain optical cable (1) to the anchor rod (2) and lay it on the fine sand soil (8), and then cover the laid strain optical cable (1) with a thicker layer of fine sand soil (8) in the trench (6); then lay the strain optical cable (1) on the thicker layer of fine sand soil (8), and then backfill the excavated sandy mudstone soil (9) on the surface of the fine sand soil (8) in the trench (6), and repeat the laying of the strain optical cable (1) in this way so that the strain optical cable (1) laid in the trench (6) is laid in a U-shape with the beginning and end connected; Strain optical cable (1) is guided from the top of the trench (6) of the slope edge rock and soil (23) to the slope slope rock and soil (24); strain optical cable (1) is directly laid on the surface of the slope slope rock and soil (24), and the strain optical cable (1) laid on the surface of the slope slope rock and soil (24) is laid in a U-shape with the ends connected; carbon steel anchor rods (2) with threads (21) are directly inserted into the surface of the slope slope rock and soil (24), and the anchor rod ears (22) at the top of the anchor rod (2) are connected to the strain optical cable (1) through iron hoops or aluminum alloy hoops (20), so that the strain optical cable (1) connected between the anchor rods (2) is in a taut state; Step S4: On the lower side of the slope rock and soil (24), the strain optical cable (1) is connected to the communication optical cable (3), wherein the end of the strain optical cable (1) is fused to the beginning of the communication optical cable (3) by means of an optical cable fusion splicer.

9. The method for monitoring landslides on open-pit coal mine slopes according to claim 8, characterized in that, Further steps include: Step S5: Laying the communication optical cable (3), binding the steel wire rope and the communication optical cable (3) together with cable ties, passing the steel wire rope and the communication optical cable (3) through the hole at the top of the cement pole (4), and connecting the end of the communication optical cable (3) to the optical switch controller (11). Step S6: Connect the data signal processing module. Transmit the strain signal of the strain optical cable (1) transmitted by the communication optical cable (3) to the data signal processing module. The relay (25) in the data signal processing module is connected to the display terminal (12) and the optical switch controller (11). The optical switch controller (11) is connected to the OTDR analyzer (28) and the BOTDR demodulator (10) through the optical cable jumper (26). The OTDR analyzer (28) and the BOTDR demodulator (10) are connected to the relay (25).

10. The method for monitoring landslides on open-pit coal mine slopes according to claim 9, characterized in that, Further steps include: Step S7: The distributed optical cable sensing and monitoring system performs a monitoring range analysis, measures the detection distance of the laid communication optical cable (3) and strain optical cable (1), and detects the connectivity of the laid strain optical cable (1) and communication optical cable (3); controls the relay (25) to enable the optical switch controller (11) to connect the BOTDR demodulator (10), so that the entire optical signal can be detected along the entire laid strain optical cable (1), and controls the display terminal (12) to modulate the optical signal.

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