A fiber optic sensing system based on multi-parameter monitoring of geotechnical engineering

Abstract

The present application discloses a fiber optic sensing system based on multi-parameter monitoring of geotechnical engineering, which relates to the field of monitoring and analysis technology, and includes a sensor deployment module, which is used to deploy sensors at each monitoring node in the target geotechnical engineering, and then confirm the signal data corresponding to each monitoring node; a demodulation module, which is used to demodulate the signal data of each monitoring node, and then confirm the parameter data corresponding to each monitoring node; a data evaluation module, which is used to analyze the parameter data corresponding to each monitoring node, and then confirm the safety score value corresponding to each monitoring node in the target geotechnical engineering; a comprehensive analysis module, which is used to compare the safety score value corresponding to each monitoring node in the target geotechnical engineering with the preset safety score interval, obtain the corresponding abnormal monitoring node in the target geotechnical engineering, output an early warning signal according to the abnormal monitoring node, and adjust based on the abnormal monitoring node. The present application has the effect of improving work efficiency.

Description

Technical Field

[0001] The present application relates to the field of monitoring and analysis technology, and in particular to an optical fiber sensing system based on multi-parameter monitoring of geotechnical engineering. Background Art

[0002] Fiber Bragg grating sensing technology obtains sensing information by modulating the wavelength of the fiber Bragg grating by external physical parameters, and realizes direct measurement of physical quantities such as temperature and strain. In addition to many advantages of ordinary optical fibers, fiber Bragg grating sensors also have their own sensing signals that are mainly wavelength modulation, and the measurement signals are not affected by light source fluctuations, fiber bending losses, light source power fluctuations, and system losses. In geotechnical engineering such as underground engineering, coal mining engineering, slope engineering, and pile foundation engineering, real-time monitoring of physical parameters of the geotechnical environment such as stress, strain, temperature, and humidity is crucial for engineering safety and risk assessment.

[0003] In the relevant technologies, there are still some areas that need to be optimized in the detection process of geotechnical engineering, which are specifically reflected in the following aspects:

[0004] At present, when using fiber Bragg grating to measure parameters in geotechnical engineering, the fiber Bragg grating has a small multiplexing capacity, poor reliability, and complex preparation and laying processes, which makes it difficult to meet the needs of geotechnical engineering monitoring, further reducing work efficiency, and there is room for improvement;

[0005] Currently, the strain data output by fiber grating sensing technology has not been analyzed from a multi-level perspective, which can easily lead to differences in the analysis data and increase the risk of safety accidents. There is room for improvement. Summary of the invention

[0006] In view of the above problems existing in the prior art, the present application provides a fiber optic sensing system based on multi-parameter monitoring of geotechnical engineering.

[0007] The present application provides a fiber optic sensing system based on geotechnical engineering multi-parameter monitoring, which adopts the following technical solutions:

[0008] An optical fiber sensing system based on geotechnical engineering multi-parameter monitoring, comprising:

[0009] The sensor deployment module is used to deploy sensors at each monitoring node in the target geotechnical engineering project, and then confirm the signal data corresponding to each monitoring node;

[0010] The demodulation module is used to demodulate the signal data of each monitoring node, and then confirm the parameter data corresponding to each monitoring node;

[0011] The data evaluation module is used to analyze the parameter data corresponding to each monitoring node, and then confirm the safety score value corresponding to each monitoring node in the target geotechnical engineering;

[0012] The comprehensive analysis module is used to compare the safety score value corresponding to each monitoring node in the target geotechnical engineering with the preset safety score interval, obtain the corresponding abnormal monitoring node in the target geotechnical engineering, and then output a warning signal according to the abnormal monitoring node, and make adjustments based on the abnormal monitoring node.

[0013] Preferably, the demodulation module includes a front-end circuit, a test unit and a signal processing unit;

[0014] The front-end circuit includes a broadband light source, a first semiconductor laser amplifier, an erbium-doped laser amplifier and a circulator; the broadband light source is connected to the first semiconductor laser amplifier, the first semiconductor laser amplifier is connected to the erbium-doped laser amplifier, wherein the circulator is provided with a first port, a second port and a third port, and the first port is connected to the erbium-doped laser amplifier;

[0015] The test unit includes a grating array optical fiber and a weak grating array optical fiber;

[0016] The signal processing unit includes a second semiconductor laser amplifier, a third semiconductor laser amplifier, an FP filter demodulation system, an imaging spectrum demodulation system and a programmable device FPGA; the second semiconductor laser amplifier is connected to the FP filter demodulation system, and the third semiconductor laser amplifier is connected to the imaging spectrum demodulation system.

[0017] Preferably, the FP filter demodulation system includes a tunable FP filter, a photodetector and a first A / D converter, the imaging spectrum demodulation system includes an InGaAs photodetector and a second A / D converter, and the programmable device FPGA includes a pulse generator, a D / A converter, a sampling controller, a time interval module, and a data transmission module;

[0018] The pulse generator is used to generate periodic pulse light and control the first semiconductor laser amplifier to output pulse light;

[0019] The D / A converter is connected to the tunable FP filter and is used to output a sawtooth wave;

[0020] The sampling controller is connected to the first A / D converter, the second A / D converter and the data transmission module for collecting signals.

[0021] Preferably, the second semiconductor laser amplifier and the third semiconductor laser amplifier are also used as optical switches; the switching states of the second semiconductor laser amplifier and the third semiconductor laser amplifier are controlled by a time interval module in the programmable device FPGA, and the second semiconductor laser amplifier and / or the third semiconductor laser amplifier are driven by a high level to make their working state ON, allowing reflected light to pass through, and OFF when the level is low, preventing reflected light from passing through;

[0022] Among them, the second semiconductor laser amplifier is connected to the FP filter demodulation system for demodulating the reflected light of the fiber grating to obtain parameter data, and the third semiconductor laser amplifier is connected to the imaging spectrum demodulation system for demodulating the reflected light of the weak fiber grating to obtain parameter data.

[0023] Preferably, the parameter data corresponding to each monitoring node is analyzed to further confirm the safety score value corresponding to each monitoring node in the target geotechnical engineering, specifically including:

[0024] Extract the strain value corresponding to each monitoring node from the parameter data corresponding to each monitoring node, and confirm the stress value corresponding to each monitoring node through Hooke's law ,in, It represents the number corresponding to each monitoring node. ;

[0025] The stress value corresponding to each monitoring node With the preset yield limit value Compare and then confirm the quantized strain type corresponding to each monitoring node, wherein if the stress value corresponding to a monitoring node is lower than the preset yield limit value, the quantized strain type corresponding to the monitoring node is set to 0, otherwise, the quantized strain type corresponding to the monitoring node is set to 1;

[0026] In the preset time window, the maximum stress value corresponding to each monitoring node is obtained, and the maximum stress value corresponding to each monitoring node is proportionally calculated with the preset design stress threshold corresponding to each monitoring node, so as to confirm the stress concentration factor corresponding to each monitoring node. ;

[0027] By calculating the formula , and obtain the safety score corresponding to each monitoring node in the target geotechnical engineering ,in, Respectively expressed as The temperature influence coefficient and quantified strain type corresponding to each monitoring node, Expressed as the preset critical stress concentration factor, Expressed as The strain rate corresponding to each monitoring node is Expressed as the strain rate correction factor, Expressed as weight coefficient.

[0028] Preferably, the safety score value corresponding to each monitoring node in the target geotechnical engineering is compared with a preset safety score interval to obtain the corresponding abnormal monitoring node in the target geotechnical engineering, and then an early warning signal is output according to the abnormal monitoring node, and adjustments are made based on the abnormal monitoring node, specifically including:

[0029] The safety score corresponding to each monitoring node in the target geotechnical engineering Compare with the preset safety score range;

[0030] If there is a security score value corresponding to the monitoring node In If the monitoring node is determined to be in a dangerous state, the monitoring node is set as an abnormal monitoring node and needs to be reinforced in time, and a first-level warning signal is output, wherein, They are respectively represented as a first preset safety score threshold and a second preset safety score threshold;

[0031] If there is a security score value corresponding to the monitoring node In the middle When the monitoring node is in the middle, it is necessary to further analyze the monitoring node and output a secondary warning signal, where: It is represented as a third preset safety score threshold, and the warning level of the first-level warning signal is greater than that of the second-level warning signal;

[0032] If the safety score value corresponding to each monitoring node Both greater than , it is determined that all monitoring nodes in the target geotechnical engineering are in a safe state and no adjustment is required.

[0033] Preferably, further analysis is performed on the monitoring node, specifically including:

[0034] Within the preset time interval, the time strain series data corresponding to the monitoring node is obtained at each acquisition time node ,in, It represents the number corresponding to each collection time node. ;

[0035] By calculating the formula , and obtain the risk coefficient corresponding to the monitoring node ,in, Expressed as the preset allowable stress difference, Expressed as correction factor;

[0036] The risk coefficient corresponding to the monitoring node The preset risk factor threshold Make a comparison;

[0037] like Less than When the monitoring node is in a safe state, it will be determined that the monitoring node is in a safe state and no adjustment is required; otherwise, the monitoring node will be set as an abnormal monitoring node and needs to be reinforced in time, and a first-level warning signal will be output.

[0038] Preferably, it also includes:

[0039] Confirm the safety score value corresponding to each monitoring node in the target geotechnical engineering , and obtain the average safety score value corresponding to the target geotechnical engineering by averaging, and establish a real-time change curve corresponding to the average safety score value of the target geotechnical engineering ;

[0040] By calculating the formula , and obtain the coefficient of variation corresponding to the average safety score of the target geotechnical engineering ;

[0041] The coefficient of variation corresponding to the average safety score of the target geotechnical engineering Preset average safety score threshold with target geotechnical engineering Make a comparison;

[0042] like Greater than , it is determined that the risk factor of the target geotechnical engineering in the future time period increases, and a warning is issued in time; otherwise, the risk factor of the target geotechnical engineering in the future time period does not increase.

[0043] In summary, the present application includes at least one of the following beneficial technical effects:

[0044] The present invention provides a fiber optic sensing system based on geotechnical engineering multi-parameter monitoring, which solves the problem of small multiplexing capacity of fiber gratings through the mutual cooperation of a sensor layout module and a demodulation module, and based on an FP filter demodulation system and an imaging spectrum demodulation system, effectively increases the poor reliability of fiber grating sensing technology, and thus effectively meets the needs of geotechnical engineering detection, thereby effectively improving work efficiency;

[0045] By analyzing the parameter data corresponding to each monitoring node, the safety score value corresponding to each monitoring node in the target geotechnical engineering project is confirmed, and the safety score value corresponding to each monitoring node in the target geotechnical engineering project is compared with the preset safety score interval to obtain the corresponding abnormal monitoring node in the target geotechnical engineering project. Then, an early warning signal is output according to the abnormal monitoring node, and adjustments are made based on the abnormal monitoring node, thereby effectively reducing the risk of safety accidents. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 It is a system schematic diagram of optical fiber sensing based on multi-parameter monitoring of geotechnical engineering according to an embodiment of the present application. DETAILED DESCRIPTION

[0047] The present application is further described in detail below in conjunction with the accompanying drawings.

[0048] Example 1

[0049] The embodiment of the present application discloses a fiber optic sensing system based on multi-parameter monitoring of geotechnical engineering.

[0050] Reference Figure 1 , an optical fiber sensing system based on geotechnical engineering multi-parameter monitoring, comprising:

[0051] The sensor deployment module is used to deploy sensors at each monitoring node in the target geotechnical engineering project, and then confirm the signal data corresponding to each monitoring node;

[0052] The demodulation module is used to demodulate the signal data of each monitoring node, and then confirm the parameter data corresponding to each monitoring node;

[0053] The data evaluation module is used to analyze the parameter data corresponding to each monitoring node, and then confirm the safety score value corresponding to each monitoring node in the target geotechnical engineering;

[0054] The comprehensive analysis module is used to compare the safety score value corresponding to each monitoring node in the target geotechnical engineering with the preset safety score threshold, obtain the corresponding abnormal monitoring node in the target geotechnical engineering, and then output a warning signal according to the abnormal monitoring node, and make adjustments based on the abnormal monitoring node.

[0055] Furthermore, the demodulation module includes a front-end circuit, a test unit and a signal processing unit;

[0056] The front-end circuit includes a broadband light source, a first semiconductor laser amplifier, an erbium-doped laser amplifier and a circulator; the broadband light source is connected to the first semiconductor laser amplifier, the first semiconductor laser amplifier is connected to the erbium-doped laser amplifier, wherein the circulator is provided with a first port, a second port and a third port, and the first port is connected to the erbium-doped laser amplifier;

[0057] The test unit includes a grating array optical fiber and a weak grating array optical fiber;

[0058] The signal processing unit includes a second semiconductor laser amplifier, a third semiconductor laser amplifier, an FP filter demodulation system, an imaging spectrum demodulation system and a programmable device FPGA; the second semiconductor laser amplifier is connected to the FP filter demodulation system, and the third semiconductor laser amplifier is connected to the imaging spectrum demodulation system.

[0059] It should be noted that the FP filter demodulation system includes a tunable FP filter, a photodetector and a first A / D converter, the imaging spectrum demodulation system includes an InGaAs photodetector and a second A / D converter, and the programmable device FPGA includes a pulse generator, a D / A converter, a sampling controller, a time interval module, and a data transmission module;

[0060] The pulse generator is used to generate periodic pulse light and control the first semiconductor laser amplifier to output pulse light;

[0061] The D / A converter is connected to the tunable FP filter and is used to output a sawtooth wave;

[0062] The sampling controller is connected to the first A / D converter, the second A / D converter and the data transmission module for collecting signals.

[0063] Specifically, the broadband light source is connected to the first semiconductor laser amplifier, and the light source emitted by the broadband light source is modulated into pulse light by the first semiconductor laser amplifier and undergoes a first-stage amplification, wherein the first semiconductor laser amplifier is controlled by the pulse generator, and the erbium-doped laser amplifier is connected to the first semiconductor laser amplifier, and the erbium-doped laser amplifier undergoes a second-stage amplification of the pulse light and is set as a pulse light source.

[0064] Specifically, the first port of the circulator is connected to the erbium-doped laser amplifier, the second port is connected to the test unit, and the third port is connected to the second semiconductor laser amplifier and the third semiconductor laser amplifier. The optical signal is transmitted along the specified ports in sequence, that is, the pulse light enters the circulator through the first port to the test unit connected to the second port, and the light reflected by the fiber grating enters the third port from the second port to the second semiconductor laser amplifier and the third semiconductor laser amplifier.

[0065] The test unit includes an optical fiber engraved with a grating array and an optical fiber with a weak grating array. A redundant optical fiber length is added between the optical fiber with a grating array and the optical fiber with a weak grating array, and the reflected light of different optical fibers is divided into different times in the time domain for transmission, thereby realizing time division multiplexing technology.

[0066] Furthermore, the second semiconductor laser amplifier and the third semiconductor laser amplifier can be used as optical switches, and the switching states of the second semiconductor laser amplifier and the third semiconductor laser amplifier are controlled by the time interval module in the programmable device FPGA, that is, the semiconductor laser amplifier is driven by a high level to make its working state ON, allowing the reflected light to pass through, and OFF at a low level to prevent the reflected light from passing through, wherein the second semiconductor laser amplifier is connected to the FP filter demodulation system, and is used to demodulate the reflected light of the fiber grating to obtain parameter data, and the third semiconductor laser amplifier is connected to the imaging spectrum demodulation system, and is used to demodulate the reflected light of the weak fiber grating to obtain parameter data. Exemplarily, since the reflected light of the fiber grating array and the weak fiber grating array are separated in the time domain, when the fiber grating return light reaches the optical switch, the second semiconductor laser amplifier is allowed to pass through and enter the FP filter demodulation system, and when the light reflected by the weak fiber grating reaches the optical switch, the third semiconductor laser amplifier is allowed to pass through and enter the imaging spectrum demodulation system, and the remaining light is isolated to realize the demodulation of the fiber grating and the weak fiber grating.

[0067] Specifically, the second semiconductor laser amplifier is connected to the tunable FP filter, the tunable FP filter is connected to the first A / D converter, and the D / A converter in the programmable device FPGA outputs sawtooth wave control to achieve demodulation of the fiber Bragg grating reflected light; the third semiconductor laser amplifier is connected to the InGaAs photodetector, and the InGaAs photodetector is connected to the second A / D converter to achieve demodulation of the weak fiber Bragg grating reflected light.

[0068] It should be noted that the parameter data corresponding to each monitoring node is analyzed to confirm the safety score value corresponding to each monitoring node in the target geotechnical engineering, including:

[0069] Extract the strain value corresponding to each monitoring node from the parameter data corresponding to each monitoring node, and confirm the stress value corresponding to each monitoring node through Hooke's law ,in, It represents the number corresponding to each monitoring node. ;

[0070] The stress value corresponding to each monitoring node With the preset yield limit value Compare and then confirm the quantized strain type corresponding to each monitoring node, wherein if the stress value corresponding to a monitoring node is lower than the preset yield limit value, the quantized strain type corresponding to the monitoring node is set to 0, otherwise, the quantized strain type corresponding to the monitoring node is set to 1;

[0071] In the preset time window, the maximum stress value corresponding to each monitoring node is obtained, and the maximum stress value corresponding to each monitoring node is proportionally calculated with the preset design stress threshold corresponding to each monitoring node, so as to confirm the stress concentration factor corresponding to each monitoring node. ;

[0072] By calculating the formula , and obtain the safety score corresponding to each monitoring node in the target geotechnical engineering ,in, Respectively expressed as The temperature influence coefficient and quantified strain type corresponding to each monitoring node, Expressed as the preset critical stress concentration factor, Expressed as The strain rate corresponding to each monitoring node is Expressed as the strain rate correction factor, Expressed as weight coefficient.

[0073] Specifically, the safety score value corresponding to each monitoring node is obtained through the stress value, quantitative strain type, stress concentration factor and strain rate corresponding to each monitoring node. Real-time monitoring of the safety score value can help staff identify potential problems in geotechnical engineering, so as to take measures in advance to prevent the problem from expanding.

[0074] Furthermore, the safety score value corresponding to each monitoring node in the target geotechnical engineering is compared with the preset safety score interval to obtain the corresponding abnormal monitoring node in the target geotechnical engineering, and then an early warning signal is output according to the abnormal monitoring node, and adjustments are made based on the abnormal monitoring node, specifically including:

[0075] The safety score corresponding to each monitoring node in the target geotechnical engineering Compare with the preset safety score range;

[0076] If there is a security score value corresponding to the monitoring node In If the monitoring node is determined to be in a dangerous state, the monitoring node is set as an abnormal monitoring node and needs to be reinforced in time, and a first-level warning signal is output, wherein, They are respectively represented as a first preset safety score threshold and a second preset safety score threshold;

[0077] If there is a security score value corresponding to the monitoring node In the middle When the monitoring node is in the middle, it is necessary to further analyze the monitoring node and output a secondary warning signal, where: It is represented as a third preset safety score threshold, and the warning level of the first-level warning signal is greater than that of the second-level warning signal;

[0078] If the safety score value corresponding to each monitoring node Both greater than , it is determined that all monitoring nodes in the target geotechnical engineering are in a safe state and no adjustment is required.

[0079] Specifically, by outputting warning signals of different warning levels, effective judgments can be made on each monitoring node based on the warning signals, thereby effectively improving the monitoring efficiency.

[0080] It should be noted that further analysis of the monitoring node specifically includes:

[0081] Within the preset time interval, the time strain series data corresponding to the monitoring node is obtained at each acquisition time node ,in, It represents the number corresponding to each collection time node. ;

[0082] By calculating the formula , and obtain the risk coefficient corresponding to the monitoring node ,in, Expressed as the preset allowable stress difference, Expressed as correction factor;

[0083] The risk coefficient corresponding to the monitoring node The preset risk factor threshold Make a comparison;

[0084] like Less than When the monitoring node is in a safe state, it will be determined that the monitoring node is in a safe state and no adjustment is required; otherwise, the monitoring node will be set as an abnormal monitoring node and needs to be reinforced in time, and a first-level warning signal will be output.

[0085] Furthermore, it also includes:

[0086] Confirm the safety score value corresponding to each monitoring node in the target geotechnical engineering , and obtain the average safety score value corresponding to the target geotechnical engineering by averaging, and establish a real-time change curve corresponding to the average safety score value of the target geotechnical engineering ;

[0087] By calculating the formula , and obtain the coefficient of variation corresponding to the average safety score of the target geotechnical engineering ;

[0088] The coefficient of variation corresponding to the average safety score of the target geotechnical engineering Preset average safety score threshold with target geotechnical engineering Make a comparison;

[0089] like Greater than , it is determined that the risk factor of the target geotechnical engineering in the future time period increases, and a warning is issued in time; otherwise, the risk factor of the target geotechnical engineering in the future time period does not increase.

[0090] Specifically, through this type of judgment method, the risk factor of the target geotechnical engineering project in the future time period can be evaluated, and potential safety hazards can be discovered in time, so as to provide timely warning and prevention.

[0091] The above contents are merely examples and explanations of the concept of the present invention. The technicians in this technical field may make various modifications or additions to the specific embodiments described or replace them in a similar manner. As long as they do not deviate from the concept of the invention or exceed the scope defined by the claims, they should all fall within the protection scope of the present invention.

[0092] In the description of this specification, the description with reference to the terms "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0093] The preferred embodiments of the present invention disclosed above are only used to help explain the present invention. The preferred embodiments do not describe all the details in detail, nor do they limit the invention to only specific implementation methods. Obviously, many modifications and changes can be made according to the content of this specification. This specification selects and specifically describes these embodiments in order to better explain the principles and practical applications of the present invention, so that those skilled in the art can understand and use the present invention well. The present invention is limited only by the claims and their full scope and equivalents.

Claims

1. An optical fiber sensing system based on multi-parameter monitoring of geotechnical engineering, characterized in that: include: A sensor deployment module is used to deploy sensors at each monitoring node in the target tunnel, and then confirm the signal data corresponding to each monitoring node; The demodulation module is used to demodulate the signal data of each monitoring node, and then confirm the parameter data corresponding to each monitoring node; The data evaluation module is used to analyze the parameter data corresponding to each monitoring node, and then confirm the safety score value corresponding to each monitoring node in the target tunnel; Analyze the parameter data corresponding to each monitoring node, and then confirm the safety score value corresponding to each monitoring node in the target tunnel, including: Extract the strain value corresponding to each monitoring node from the parameter data corresponding to each monitoring node, and confirm the stress value corresponding to each monitoring node through Hooke's law ,in, It represents the number corresponding to each monitoring node. ; The stress value corresponding to each monitoring node With the preset yield limit value Compare and then confirm the quantized strain type corresponding to each monitoring node, wherein if the stress value corresponding to a monitoring node is lower than the preset yield limit value, the quantized strain type corresponding to the monitoring node is set to 0, otherwise, the quantized strain type corresponding to the monitoring node is set to 1; In the preset time window, the maximum stress value corresponding to each monitoring node is obtained, and the maximum stress value corresponding to each monitoring node is proportionally calculated with the preset design stress threshold corresponding to each monitoring node, so as to confirm the stress concentration factor corresponding to each monitoring node. ; By calculating the formula , and obtain the security score corresponding to each monitoring node in the target tunnel ,in, Respectively expressed as The temperature influence coefficient and quantified strain type corresponding to each monitoring node, Expressed as the preset critical stress concentration factor, Expressed as The strain rate corresponding to each monitoring node is Expressed as the strain rate correction factor, Expressed as weight coefficient; The comprehensive analysis module is used to compare the security score value corresponding to each monitoring node in the target tunnel with the preset security score interval, obtain the corresponding abnormal monitoring node in the target tunnel, and then output a warning signal according to the abnormal monitoring node, and make adjustments based on the abnormal monitoring node.

2. The optical fiber sensing system based on geotechnical engineering multi-parameter monitoring according to claim 1 is characterized in that: The demodulation module includes a front-end circuit, a test unit and a signal processing unit; The front-end circuit includes a broadband light source, a first semiconductor laser amplifier, an erbium-doped laser amplifier and a circulator; the broadband light source is connected to the first semiconductor laser amplifier, the first semiconductor laser amplifier is connected to the erbium-doped laser amplifier, wherein the circulator is provided with a first port, a second port and a third port, and the first port is connected to the erbium-doped laser amplifier; The test unit includes a grating array optical fiber and a weak grating array optical fiber; The signal processing unit includes a second semiconductor laser amplifier, a third semiconductor laser amplifier, an FP filter demodulation system, an imaging spectrum demodulation system and a programmable device FPGA; the second semiconductor laser amplifier is connected to the FP filter demodulation system, and the third semiconductor laser amplifier is connected to the imaging spectrum demodulation system.

3. The optical fiber sensing system based on geotechnical engineering multi-parameter monitoring according to claim 2 is characterized in that: The FP filter demodulation system includes a tunable FP filter, a photodetector and a first A / D converter, the imaging spectrum demodulation system includes an InGaAs photodetector and a second A / D converter, and the programmable device FPGA includes a pulse generator, a D / A converter, a sampling controller, a time interval module, and a data transmission module; The pulse generator is used to generate periodic pulse light and control the first semiconductor laser amplifier to output pulse light; The D / A converter is connected to the tunable FP filter and is used to output a sawtooth wave; The sampling controller is connected to the first A / D converter, the second A / D converter and the data transmission module for collecting signals.

4. The optical fiber sensing system based on geotechnical engineering multi-parameter monitoring according to claim 3 is characterized in that: The second semiconductor laser amplifier and the third semiconductor laser amplifier are also used as optical switches; the switching states of the second semiconductor laser amplifier and the third semiconductor laser amplifier are controlled by a time interval module in the programmable device FPGA, and the second semiconductor laser amplifier and / or the third semiconductor laser amplifier are driven by a high level to be in an ON state, allowing the reflected light to pass through, and are in an OFF state when the level is low, preventing the reflected light from passing through; Among them, the second semiconductor laser amplifier is connected to the FP filter demodulation system for demodulating the reflected light of the fiber grating to obtain parameter data, and the third semiconductor laser amplifier is connected to the imaging spectrum demodulation system for demodulating the reflected light of the weak fiber grating to obtain parameter data.

5. The optical fiber sensing system based on geotechnical engineering multi-parameter monitoring according to claim 1 is characterized in that: Compare the security score value corresponding to each monitoring node in the target tunnel with the preset security score interval to obtain the corresponding abnormal monitoring node in the target tunnel, and then output a warning signal according to the abnormal monitoring node, and make adjustments based on the abnormal monitoring node, specifically including: The security score corresponding to each monitoring node in the target tunnel Compare with the preset safety score range; If there is a security score value corresponding to the monitoring node In If the monitoring node is determined to be in a dangerous state, the monitoring node is set as an abnormal monitoring node and needs to be reinforced in time, and a first-level warning signal is output, wherein, They are respectively represented as a first preset safety score threshold and a second preset safety score threshold; If there is a security score value corresponding to the monitoring node In the middle When the monitoring node is in the middle, it is necessary to further analyze the monitoring node and output a secondary warning signal, where: It is represented as a third preset safety score threshold, and the warning level of the first-level warning signal is greater than that of the second-level warning signal; If the safety score value corresponding to each monitoring node Both greater than , it is determined that all monitoring nodes in the target tunnel are in a safe state and no adjustment is required.

6. The optical fiber sensing system based on geotechnical engineering multi-parameter monitoring according to claim 5, characterized in that: Further analysis of the monitoring node includes: Within the preset time interval, the time strain series data corresponding to the monitoring node is obtained at each acquisition time node ,in, It represents the number corresponding to each collection time node. ; By calculating the formula , and obtain the risk coefficient corresponding to the monitoring node ,in, Expressed as the preset allowable stress difference, Expressed as correction factor; The risk coefficient corresponding to the monitoring node The preset risk factor threshold Make a comparison; like Less than When the monitoring node is in a safe state, it will be determined that the monitoring node is in a safe state and no adjustment is required; otherwise, the monitoring node will be set as an abnormal monitoring node and needs to be reinforced in time, and a first-level warning signal will be output.

7. The optical fiber sensing system based on geotechnical engineering multi-parameter monitoring according to claim 6 is characterized in that: Also includes: Confirm the security score value corresponding to each monitoring node in the target tunnel , and obtain the average safety score value corresponding to the target tunnel by averaging, and establish a real-time change curve corresponding to the average safety score value of the target tunnel ; By calculating the formula , and obtain the coefficient of variation corresponding to the average safety score of the target tunnel ; The coefficient of change corresponding to the average safety score of the target tunnel Preset average security score threshold for target tunnel Make a comparison; like Greater than , then it is determined that the risk factor of the target tunnel in the future time period increases, and an early warning is issued in time; otherwise, the risk factor of the target tunnel in the future time period does not increase.

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