Distributed optical fiber sensing device for earthquake monitoring

Abstract

The utility model discloses a distributed optical fiber sensing device for earthquake monitoring, which comprises an optical cable, a module laying unit is sleeved outside the optical cable, and an auxiliary laying structure is arranged on the module laying unit; the utility model relates to a distributed optical fiber sensing device, a plurality of adjusting parts are spliced in a snakelike shape to form a module laying unit, the length of an optical cable is multiplied in the same projection area, the density of monitoring points is improved, the monitoring quality is improved, and the laying density of the optical cable is adjusted by operating a manual adjusting assembly and adjusting the distance between two adjacent middle pipes. When an earthquake-prone zone is monitored, the laying density of optical cables needs to be large, namely, the distance between two adjacent middle pipes is shortened, the spatial resolution is improved, tiny strain and high-frequency vibration are more accurately captured, adjacent seismic sources can be distinguished, when an earthquake is not prone to happening, the laying density of the optical cables is small, the construction cost is saved, and the construction efficiency is improved. The coverage range can be adjusted through the auxiliary laying structure.

Description

TECHNICAL FIELD

[0001] The utility model relates to distributed optical fiber sensing device, concretely is a kind of for the distributed optical fiber sensing device of earthquake monitoring. BACKGROUND

[0002] Distributed optical fiber sensor (DAS) has significant advantages in earthquake monitoring, which can realize high-density and high-precision monitoring of surface and underground structures. Its core principle is based on the sensitivity of Rayleigh backscattering signal in optical fiber to slight deformation. By analyzing the phase change of optical pulse signal, the vibration information of seismic wave can be accurately extracted.

[0003] The propagation of seismic waves has obvious directional characteristics, i.e. the vertical vibration of longitudinal waves is significant, while the horizontal vibration of transverse waves is dominant. Traditional cable laying is linear, which results in poor sensitivity in capturing both types of seismic waves. Moreover, there is a significant difference in monitoring density required for active fault zones and stable blocks. Linear laying method is not convenient for adjusting monitoring point density according to different geological risk areas.

[0004] To solve the above problems, there may be technical means to solve them in the prior art, but the present case wants to provide an alternative or replacement technical solution. UTILITY MODEL CONTENT

[0005] To solve the problems raised in the background art, the utility model realizes the following technical scheme: a distributed optical fiber sensing device for earthquake monitoring, comprising an optical cable, a module laying unit is externally fitted on the optical cable, an auxiliary laying structure is provided on the module laying unit, and the module laying unit is composed of a plurality of adjusting parts in a serpentine joint.

[0006] Each adjusting part comprises a first right-angle pipe and a second right-angle pipe, a middle pipe is fixedly inserted at one end of the first right-angle pipe, the second right-angle pipe is movably fitted at one end of the middle pipe, the first right-angle pipe, the second right-angle pipe and the middle pipe are arranged in an S-shaped structure, elastic connecting components are provided on the first right-angle pipe and the second right-angle pipe, fixed discs are fitted on the outer side walls of the first right-angle pipe and the second right-angle pipe, end flange pipes are movably fitted at one end of the first right-angle pipe and the second right-angle pipe, and hand-operated adjusting components are provided between the end flange pipes and the fixed discs.

[0007] End fixing frames are provided on the first right-angle pipe and the second right-angle pipe along the axial direction of the middle pipe, and two middle fixing frames are symmetrically provided on the first right-angle pipe and the second right-angle pipe along the radial direction of the middle pipe.

[0008] Preferably, the manual adjusting assembly comprises a moving disc fixedly sleeved on the end flange pipe, a threaded rod is installed on the moving disc, an internally threaded sleeve is threadedly sleeved on the threaded rod, the internally threaded sleeve is movably inserted on a fixed disc, and a guide telescopic rod is arranged between the moving disc and the fixed disc.

[0009] Preferably, the auxiliary laying structure comprises a base, a plurality of electric push rods are arranged on the base, and a top plate is installed on the telescopic end of the plurality of electric push rods.

[0010] Preferably, the elastic connecting assembly comprises two connecting discs, the two connecting discs are fixedly sleeved on the first right-angle pipe and the second right-angle pipe respectively, and a plurality of spring columns are arranged between the two connecting discs.

[0011] Preferably, a plurality of mounting holes are formed in the end fixing frame, the two middle fixing frames and the base.

[0012] Preferably, an inclined surface is formed at the end of the middle pipe and the end flange pipe.

[0013] Beneficial effects

[0014] The utility model provides a kind of distributed optical fiber sensing device for seismic monitoring, compared with prior art, with the following beneficial effects: multiple adjusting parts are snake-shapedly spliced to form module laying unit, realize the length multiplication of optical cable in the same projection area, improve the monitoring point density, improve the monitoring quality, by operating manual adjusting assembly, the distance between adjacent two middle pipes is adjusted, the adjustment of optical cable laying density is realized, when monitoring earthquake-prone zone, optical cable laying density needs to be larger, i.e. shorten the distance between adjacent two middle pipes, improve spatial resolution, more accurate capture tiny strain and high frequency vibration, help to distinguish adjacent seismic source, when monitoring area where earthquake is not easy to occur, optical cable laying density is smaller, save construction cost, the coverage range can be adjusted by auxiliary laying structure. BRIEF DESCRIPTION OF DRAWINGS

[0015] Fig. 1 It is a whole three-dimensional structure schematic view of the utility model one kind for seismic monitoring distributed optical fiber sensing device.

[0016] Fig. 2 It is a local three-dimensional structure schematic view of the utility model one kind for seismic monitoring distributed optical fiber sensing device.

[0017] Fig. 3 It is a local main view sectional structure schematic view of the utility model one kind for seismic monitoring distributed optical fiber sensing device.

[0018] In the figure: 1, optical cable, 2, first elbow, 3, second elbow, 4, middle tube, 5, fixed disc, 6, end flange tube, 7, end fixed frame, 8, middle fixed frame, 9, moving disc, 10, threaded rod, 11, internally threaded sleeve, 12, base, 13, electric push rod, 14, top plate, 15, connecting disc, 16, spring post, 17, mounting hole, 18, bevel, 19, guide telescopic rod. DETAILED DESCRIPTION

[0019] Based on the embodiments in the utility model, all other embodiments obtained by those skilled in the art without making creative labor belong to the scope of protection of the utility model.

[0020] Embodiment: through the personnel in the art, all electrical components in the case and the power supply matched with them are connected through wires, and appropriate controllers should be selected according to actual conditions to meet the control requirements, and the specific connection and control sequence should be completed according to the working order between the electrical components in the following working principle, and the detailed connection means is the public technical knowledge in the art, and the following mainly introduces the working principle and process, and the electrical control is not described.

[0021] Please refer to Figs. 1-3 In order to solve the problem that the traditional optical cable 1 is laid in a straight line type, the sensitivity for simultaneously capturing two types of seismic waves is poor, and there is a magnitude difference in the required monitoring density between the active fault zone and the stable block, and the straight laying mode is not convenient for adjusting the monitoring point density according to different geological risk areas, the technical scheme is designed, and the detailed technical scheme is as follows.

[0022] A kind of distributed optical fiber sensing device for seismic monitoring, including optical cable 1, optical cable 1 is equipped with module laying unit outside, auxiliary laying structure is provided on module laying unit, and module laying unit is composed of multiple adjusting parts in the shape of snake;

[0023] It should be noted that the multiple adjusting parts are connected in the shape of snake to form the module laying unit, and in actual work, the length of the module laying unit can be adjusted by increasing or decreasing the number of adjusting parts, the optical cable 1 is arranged inside the module laying unit, and when performing seismic monitoring, the distributed optical fiber vibration monitoring host is connected to one end of the optical cable 1, and the specific structure and working principle of the optical cable 1 and the distributed optical fiber vibration monitoring host can be referred to the intelligent distributed optical fiber vibration monitoring host produced by Hebei Micro Exploration Technology Co., Ltd., which is prior art and will not be described in detail.

[0024] Specifically, each adjusting part comprises a first straight pipe 2 and a second straight pipe 3, the first straight pipe 2 is fixedly sleeved with a middle pipe 4 at one end, the second straight pipe 3 is movably sleeved at one end of the middle pipe 4, the first straight pipe 2, the second straight pipe 3 and the middle pipe 4 are arranged in an S-shaped structure, the first straight pipe 2 and the second straight pipe 3 are provided with elastic connecting assemblies, the first straight pipe 2 and the second straight pipe 3 are both sleeved with a fixed disc 5 on the outer wall surface, the first straight pipe 2 and the second straight pipe 3 are both movably sleeved with an end flange pipe 6 at one end, and the end flange pipe 6 is provided with a manual adjusting assembly between the fixed disc 5;

[0025] It should be noted that when laying multiple adjusting parts, the end flange pipe 6 can be moved at one end of the first straight pipe 2 and the second straight pipe 3 by operating the manual adjusting assembly, the overall length of the adjusting part is adjusted, the end flange pipes 6 in the two adjacent adjusting parts are connected symmetrically with each other to form a serpentine structure, which is equivalent to adjusting the distance between the two adjacent middle pipes 4, and the laying density of the optical cable 1 is adjusted. When monitoring the earthquake-prone zone, the laying density of the optical cable 1 needs to be large, that is, the distance between the two adjacent middle pipes 4 is shortened, the spatial resolution is improved, and the micro-strain and high-frequency vibration can be captured more accurately, which is helpful to distinguish adjacent seismic sources. When monitoring the area where earthquakes are not easy to occur, the laying density of the optical cable 1 is small, and the construction cost is saved.

[0026] Specifically, the manual adjusting assembly comprises a moving disc 9, the moving disc 9 is fixedly sleeved on the end flange pipe 6, a threaded rod 10 is installed on the moving disc 9, an internal threaded sleeve 11 is threadedly sleeved on the threaded rod 10, the internal threaded sleeve 11 is movably sleeved on the fixed disc 5, and a guide telescopic rod 19 is further arranged between the moving disc 9 and the fixed disc 5;

[0027] It should be noted that by rotating the internal threaded sleeve 11 on the fixed disc 5, the threaded rod 10 moves along the axial direction of the internal threaded sleeve 11 under the threaded connection, and the end flange pipe 6 moves at one end of the first straight pipe 2 and the second straight pipe 3 under the connection of the moving disc 9;

[0028] Specifically, the first straight pipe 2 and the second straight pipe 3 are both provided with an end fixed frame 7 along the axial direction of the middle pipe 4, and the first straight pipe 2 and the second straight pipe 3 are both provided with two middle fixed frames 8 symmetrically along the radial direction of the middle pipe 4;

[0029] It should be noted that when the module laying unit needs to be laid horizontally underground, the middle fixing frame 8 can be fixed on the installation plane, that is, the optical cable 1 is laid in a horizontal direction underground, which is used for faster detection of transverse waves in an earthquake, and when the module laying unit needs to be laid vertically underground, the end fixing frame 7 can be fixed on the installation plane, that is, the optical cable 1 is laid in a vertical direction underground, which is used for faster detection of longitudinal waves in an earthquake. The two laying methods can be combined to form three-dimensional monitoring, simultaneously capture depth and plane signals, and improve the accuracy of early warning. The serpentine laying can double the length of the optical cable 1 in the same projection area, improve the monitoring point density, and improve the monitoring quality.

[0030] Specifically, the auxiliary laying structure includes a base 12, a plurality of electric push rods 13 are arranged on the base 12, and a top plate 14 is installed at the extension end of the plurality of electric push rods 13. The module laying unit is installed on the opposite wall surface of the base 12 and the top plate 14.

[0031] It should be noted that when the distance between the second straight pipe 3 and the first straight pipe 2 needs to be adjusted, the end fixing frame 7 is first fixed and installed between the base 12 and the top plate 14, and the plurality of electric push rods 13 are connected to the power supply and the control system. By working of the plurality of electric push rods 13, the distance between the top plate 14 and the base 12 is increased, driving the second straight pipe 3 to move upward, the second straight pipe 3 moves at one end of the middle pipe 4, the height size of the module laying unit is adjusted, the coverage range is expanded, and then the base 12 and the top plate 14 are fixed and installed on the installation surface underground. When the module laying unit is fixed, the optical cable 1 can pass through the module laying unit;

[0032] Specifically, the elastic connection assembly includes two connecting discs 15, the two connecting discs 15 are fixedly sleeved on the first straight pipe 2 and the second straight pipe 3 respectively, and a plurality of spring columns 16 are arranged between the two connecting discs 15.

[0033] It should be noted that in a natural state, the plurality of spring columns 16 are in a contracted state, and the first straight pipe 2 and the second straight pipe 3 are elastically connected under the connection of the two connecting discs 15, preventing the second straight pipe 3 from falling off from one end of the middle pipe 4. When the electric push rod 13 is elongated, the plurality of spring columns 16 are stretched under the connection of the two connecting discs 15, so that the distance between the second straight pipe 3 and the first straight pipe 2 is adjusted.

[0034] As a preferred further, a plurality of mounting holes 17 are formed in the end fixing frame 7, the two middle fixing frames 8 and the base 12, for inserting fasteners such as bolts and nuts.

[0035] As preferred, further, the middle pipe 4 and the end of the end flange pipe 6 are both provided with a bevel 18, which facilitates the cable to pass through the connection between the middle pipe 4 and the end flange pipe 6 and the first right-angle pipe 2 and the second right-angle pipe 3.

[0036] Although the embodiments of the present application have been shown and described, it is to be understood that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present application, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A distributed optical fiber sensing device for seismic monitoring comprising an optical cable (1), characterized in that, The optical cable (1) is externally sleeved with a module laying unit, the module laying unit is provided with an auxiliary laying structure, and the module laying unit is composed of a plurality of adjusting parts in a snake shape. Each adjusting part comprises a first straight pipe (2) and a second straight pipe (3), one end of the first straight pipe (2) is fixedly sleeved with a middle pipe (4), one end of the second straight pipe (3) is movably sleeved with the middle pipe (4), the first straight pipe (2), the second straight pipe (3) and the middle pipe (4) are arranged in an S-shaped structure, the first straight pipe (2) and the second straight pipe (3) are provided with an elastic connecting assembly, the first straight pipe (2) and the second straight pipe (3) are both sleeved with a fixed disc (5) on the outer side wall surface, one end of the first straight pipe (2) and the second straight pipe (3) is movably sleeved with an end flange pipe (6), and a manual adjusting assembly is arranged between the end flange pipe (6) and the fixed disc (5). The first straight pipe (2) and the second straight pipe (3) are both provided with an end fixing frame (7) along the axial direction of the middle pipe (4), and the first straight pipe (2) and the second straight pipe (3) are both provided with two middle fixing frames (8) symmetrically along the radial direction of the middle pipe (4).

2. A distributed optical fibre sensing apparatus for seismic monitoring according to claim 1, characterised in that, The manual adjusting assembly comprises a moving disc (9), the moving disc (9) is fixedly sleeved on the end flange pipe (6), a threaded rod (10) is installed on the moving disc (9), an internal threaded sleeve (11) is threadedly sleeved on the threaded rod (10), the internal threaded sleeve (11) is movably sleeved on the fixed disc (5), and a guide telescopic rod (19) is further arranged between the moving disc (9) and the fixed disc (5).

3. The distributed fiber optic sensing apparatus for seismic monitoring of claim 1, wherein, The auxiliary laying structure comprises a base (12), a plurality of electric push rods (13) are arranged on the base (12), a top plate (14) is installed on the telescopic end of the plurality of electric push rods (13), and the module laying unit is installed on the opposite wall surface of the base (12) and the top plate (14).

4. The distributed fiber optic sensing apparatus for seismic monitoring of claim 1, wherein, The elastic connecting assembly comprises two connecting discs (15), the two connecting discs (15) are fixedly sleeved on the first straight pipe (2) and the second straight pipe (3) respectively, and a plurality of spring columns (16) are arranged between the two connecting discs (15).

5. The distributed fiber optic sensing apparatus for seismic monitoring of claim 1, wherein, The end fixing frame (7), the two middle fixing frames (8) and the base (12) are all provided with a plurality of mounting holes (17).

6. The distributed fiber optic sensing apparatus for seismic monitoring of claim 1, wherein, The end of the middle pipe (4) and the end of the end flange pipe (6) are both provided with an inclined surface (18).

Images