CN111335954A - Rock burst monitoring system based on distributed optical fiber sensing and data acquisition and processing method - Google Patents
Rock burst monitoring system based on distributed optical fiber sensing and data acquisition and processing method Download PDFInfo
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- CN111335954A CN111335954A CN202010322324.2A CN202010322324A CN111335954A CN 111335954 A CN111335954 A CN 111335954A CN 202010322324 A CN202010322324 A CN 202010322324A CN 111335954 A CN111335954 A CN 111335954A
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Abstract
The invention discloses a distributed optical fiber sensing-based rockburst monitoring system and a data acquisition and processing method.A plurality of monitoring armored optical cables are supported on a rock mass or a supporting wall body along the top and two sides of a tunnel which is being tunneled or completed, or are fixedly installed on a working face which is being excavated along a mountain or a mineral body; one end of each monitoring armored optical cable is connected with the multi-channel wide-frequency distributed optical fiber sound wave and strain sensing modulation and demodulation system, and the multi-channel wide-frequency distributed optical fiber sound wave and strain sensing modulation and demodulation system is connected with the real-time data recording and processing computer. When a local section is subjected to strain, displacement and fracture and a large number of micro-seismic events are induced on a monitored tunnel or working face due to underground stress accumulation and concentration, the strain and the displacement are generated on the corresponding local section on the monitoring armored optical cable at the same time, and the strain, the displacement and the micro-seismic events which are measured and monitored in real time are used for early warning or processing or reinforcing the local section, which is possibly subjected to rock burst, on a monitored rock body in advance.
Description
Technical Field
The invention relates to the technical field of geophysical exploration, in particular to a rock burst monitoring system based on distributed optical fiber sensing and a data acquisition and processing method.
Background
Rock burst, also known as rock burst, is a phenomenon in which elastic deformation potential energy accumulated in a rock mass is suddenly and violently released under certain conditions, causing the rock to burst and be ejected. The main cause of rock burst is the sudden destabilizing failure of surrounding rock without the strength of the surrounding rock accommodating the concentrated excessive stress. Rock burst is one of the main potential safety hazards faced in tunnels and deep-well mines. The slight rock burst only has spalling rock slices, has no ejection phenomenon, can seriously measure 4.6-grade earthquake magnitude, and the intensity reaches 7-8 degrees, so that the ground building is damaged and is accompanied with great sound. The rock burst may occur instantaneously or may last from days to months. The condition of rock burst is that the rock mass has higher ground stress and exceeds the strength of the rock, and the rock has higher brittleness and elasticity, under the condition, once the original balance state of the rock mass is destroyed by underground engineering activity, the energy accumulated in the rock mass is released to cause the rock to be destroyed, and broken rock is thrown out.
Rock burst of tunnels and deep-well mines is a common dynamic destruction phenomenon in the construction process of deep-buried underground engineering, when high elastic strain energy accumulated in rock mass is larger than energy consumed by rock destruction, the balance of rock mass structure is destroyed, and redundant energy causes rock burst, so that rock fragments are stripped and burst out of the rock mass. Rock burst of tunnels and deep-well mines is a destructive phenomenon of rock fragmentation, ejection, even earthquake and the like caused by sudden release of elastic deformation energy of fragile rocks in a high-stress state due to excavation, the mechanical mechanism of the rock fragmentation, ejection and even earthquake is relatively complex, and the current research on the rock fragmentation, ejection and even earthquake is mostly stopped in hypothesis and experience stages. As a dynamic instability phenomenon induced by multi-factor coupling, the complexity of a rock burst forming mechanism and related theories are imperfect, so that the actual application effect of a rock burst prediction theory is not ideal, and a set of mature theory and method do not exist in China. In recent years, more and more rock burst problems are highlighted, rock burst not only damages production equipment and delays construction period, but also seriously threatens personal safety of constructors, and the rock burst becomes a great technical obstacle in future deep-buried underground engineering construction in China.
Rock burst often causes serious damage to an excavation working face, equipment damage and personal casualties, and becomes a worldwide problem in the fields of rock underground engineering and rock mechanics. Slight rock burst only peels off the rock slices, and no ejection phenomenon exists. Severe magnitude of 4.6 magnitude can be measured, typically lasting days or months. The reason for rock burst is that the rock has higher ground stress and exceeds the strength of the rock, and the rock has higher brittleness and elasticity. At this time, once the balance of rock mass is broken by underground engineering, the rock is broken by strong energy, and broken rock is thrown out. The method for preventing rock burst is stress relief method, water injection softening method and anchor bolt-steel wire mesh-concrete support.
The rock burst occurrence condition is that (1) the earth stress in deep ore rocks is higher due to recent tectonic activities, larger strain energy is stored in the rock mass, and when the energy of the part exceeds the strength of the rock, a rock burst event can occur;
(2) the surrounding rock which is hard, fresh and complete, has few or only hidden cracks and has higher brittleness and elasticity can store energy, the deformation characteristic of the surrounding rock belongs to a brittle failure type, and when the stress is relieved due to engineering excavation, the rock is likely to crack and pop up due to small rebound deformation;
(3) if the underground water is less, the rock mass is dry and rock burst is easy to occur;
(4) the underground engineering with irregular section shape and more branch holes of large-scale cavern groups or the zone with local stress concentration caused by section change is an area where rock burst is easy to occur.
The deep well mine rock burst has the following characteristics:
(1) burstiness: before the occurrence of the rock burst noise, no obvious positive sound exists, even no air noise can be heard, the rock burst noise can be suddenly generated at a place where the rock cannot fall, and the rock sometimes falls due to the sound and sometimes cannot fall temporarily.
(2) Site concentration: although there are individual cases where the rock burst occurs at a location that is relatively far from the newly excavated face of the T-face, most of it occurs near the newly excavated face. The common rockburst part is the most of arch part or arch waist part.
(3) Time concentration and duration: rock burst appears continuously after blasting or excavation, mostly occurs within 24 hours after blasting, the duration is generally 1-2 months, some rock bursts are prolonged by more than 1 year, and no obvious sign exists in advance.
(4) Ejection property: during rock burst, the rock mass is ejected from the surrounding rock matrix of the tunnel wall and generally takes the shape of an irregular sheet with a thick middle edge and a thin side.
Rock burst is one of major disasters threatening mine safety production, has sudden and disastrous performances, but has spatial and temporal implications in the accumulation process, so that on the basis of deeply understanding the rock burst occurrence mechanism, the spatial position and the temporal effect of the rock burst occurrence need to be predicted, and effective prevention and treatment measures are taken, so that the loss caused by the rock burst is avoided and reduced.
In the prior art, a rock burst monitoring system can generally monitor the following: (1) monitoring the convergence rate; (2) monitoring earthquake activity; (3) monitoring microseismic activity; (4) and (5) measuring the rock mass stress. The existing rock burst monitoring and early warning scheme which is feasible at present is multi-technology integration. The specific techniques that are possible are as follows: 1. and (3) ground stress test: a hollow bag body; 2. rapidly acquiring tunnel surrounding rock structure parameters: three-dimensional photogrammetry and rock mass structure analysis; 3. the three-dimensional stress field of the tunnel surrounding rock changes: a high-precision triaxial drilling strain gauge; 4. passive and active microseismic high-precision monitoring; the rockburst is a special earthquake, and monitoring and early warning of the rockburst are realized by using quantitative seismology and engineering seismology; 5. the method comprises the following steps of rapidly testing on-site rock physical and mechanical parameters, drilling a hole, and the like; 6. rockburst risk management software and rockburst treatment technology.
At present, the prevailing rock burst activity is observed by a microseismic monitoring technology, and although no obvious sign exists before the rock burst occurs, technicians find that the occurrence time of the general rock burst is mainly concentrated in 2-6 hours after the burst through detailed observation. In recent years, microseismic monitoring is rapidly developed as a method for effectively positioning rock mass fracture and monitoring strength in three-dimensional space. The microseismic monitoring technology can analyze the time, the position and the magnitude of a seismic source damage event (also called as three elements of space-time intensity) through sound waves, thereby providing potential possibility for rock burst prediction, and a microseismic monitoring system with higher sensitivity can capture rock micro-fracture precursor events with smaller magnitude than the rock burst magnitude.
The defects of the prior art are that almost all rock burst monitoring technologies and means rely on various sensors sparsely arranged in a tunnel or on a working surface to measure various rock mechanical parameters and local volume change characteristics of a rock body in real time, and the possibility of rock burst is monitored or predicted through data calculation and processing results. The monitoring of the possibility of rock burst along the whole tunnel or on the whole excavation working face by the sparsely arranged sensors is inaccurate or incomplete, and it is difficult to accurately determine the specific position or section where rock burst may occur by processing the monitoring data, and it is also difficult to effectively reinforce or otherwise process the specific position or section where rock burst may occur.
For example, the existing commonly used rockburst micro-seismic monitoring technology is a method and means for monitoring micro-seismic events occurring before rockburst occurs by only depending on a small number of conventional detectors sparsely distributed in a monitored area. However, the micro-seismic monitoring technology cannot accurately measure the slow strain and displacement caused by the concentration and accumulation of underground stress on the top and two sides of the tunnel supporting rock mass or the mountain or the excavation working surface of the ore body, and only can record the micro-seismic event with larger energy induced when the rock mass is cracked. Although the micro-seismic events monitored in the area or section where the rock burst is about to occur are directly related to the rock burst, the micro-seismic monitoring result close to the occurrence of the rock burst has no way of providing sufficient early warning time for constructors, and has no time for timely processing or reinforcing the dangerous part or section of the monitored rock mass before the rock burst occurs. In addition, because the rockburst micro-seismic monitoring system using a limited number of detectors is used, the recorded micro-seismic data amount is small, the processing result has low estimation precision on the positioning and energy intensity of the micro-seismic event, and the specific position and possible occurrence time of the rockburst are difficult to predict accurately.
Disclosure of Invention
In order to solve the problems in the prior art, the invention discloses a rock burst monitoring system based on distributed optical fiber sensing and a data acquisition and processing method, and solves the problems that the slow strain and displacement caused by underground stress concentration and accumulation on a supporting rock body at the top and two sides of a tunnel or a mountain body or an excavation working surface of the rock body can not be accurately measured and only the micro seismic event with larger energy induced when the rock body is broken can be recorded by using the conventional method and means for measuring and monitoring the mechanical parameters of the rock body before the rock burst occurs only by using a small number of various sensors which are sparsely distributed or monitoring the micro seismic event occurring before the rock burst occurs by using a limited number of conventional detectors. Although the micro-seismic events monitored in the area or section of the rock mass about to have the rock burst are directly related to the rock burst, the monitoring result of the micro-seismic events close to the rock burst before occurrence has no way of providing enough early warning time for constructors, and has no time for timely processing or reinforcing the dangerous part or section of the monitored rock mass before the rock burst occurs.
The invention provides a distributed optical fiber sensing-based rock burst monitoring system and a data acquisition and processing method, and adopts the technical scheme that:
the rock burst monitoring system based on distributed optical fiber sensing comprises a plurality of monitoring armored optical cables, a multi-channel broadband distributed optical fiber sound wave and strain sensing modulation and demodulation system and a real-time data recording, storing and processing computer system, wherein the monitoring armored optical cables are fixedly installed on a supporting rock body or a supporting wall body along the top and two sides of an excavation or tunneling or finished tunnel or on a working surface along the excavation or excavation of a mountain or an ore body; one end of each monitoring armored optical cable is connected with the multi-channel wide-frequency distributed optical fiber sound wave and strain sensing modulation and demodulation system, and the multi-channel wide-frequency distributed optical fiber sound wave and strain sensing modulation and demodulation system is connected with the real-time data recording, storing and processing computer system.
The monitoring armored optical cable is an armored optical cable wound in a spiral shape.
And the monitoring armored optical cables are parallel to the extending direction of the tunnel or the spreading direction of the working surface.
The distance between the adjacent monitoring armored optical cables is not more than 1 meter; the length of each monitoring armored cable covers the entire length of the tunnel or the entire length of the working face.
The monitoring armored optical cable is fixed by cement or staples and is fixed on a supporting rock body or a supporting wall body at the top and two sides of the tunnel or is fixed on a working face.
And the other ends of all the monitoring armored optical cables are provided with extinction devices. The extinction device is an extinction device arranged at the tail end of the monitoring armored optical cable, or the tail end of the optical fiber is knotted, so that strong reflection signals of the optical fiber at the tail end point are eliminated.
The data acquisition and processing method of the distributed optical fiber sensing-based rock burst monitoring system comprises the following steps:
s1: the monitoring armored optical cables are installed and fixed on the monitored rock mass through cement or staple bolts and are connected to the multi-channel wide-frequency distributed optical fiber sound wave and strain sensing modulation and demodulation system, the multi-channel wide-frequency distributed optical fiber sound wave and strain sensing modulation and demodulation system is started, and phase change information of backscattered Rayleigh light, transmitted to the multi-channel wide-frequency distributed optical fiber sound wave and strain sensing modulation and demodulation system by each monitoring armored optical cable, is continuously measured and recorded;
s2: comparing and analyzing the phase data of the backscattered Rayleigh light recorded by each measurement with the phase data of the backscattered Rayleigh light recorded in the front;
s3: when the phase data of the back scattering Rayleigh light, which are measured and recorded twice, are different or change at a certain position of the monitoring armored optical cable, the phase difference exclusive-or change data is converted into the strain or displacement data of the optical fiber through the multi-channel wide-frequency distribution type optical fiber sound wave and phase data processing software built in the strain sensing modulation and demodulation system, and then the strain or displacement data detected by the monitoring armored optical cable is transmitted to a real-time data recording and processing computer system on a monitoring site;
s4: after receiving strain or displacement data along each monitoring armored optical cable transmitted by the multichannel broadband distributed optical fiber sound wave and strain sensing modulation and demodulation system, the real-time data recording and processing computer system projects the data of rock mass strain or displacement on each monitoring armored optical cable onto a rock mass plane layout graph monitored by the real-time data recording and processing computer system through real-time calculation and statistical analysis processing;
s5: the time differential (first derivative) is obtained from the data of the rock mass strain on each monitoring armored optical cable, the change rate of the rock mass strain data on each monitoring armored optical cable along with time is obtained, and the change rate data of the rock mass strain data on each monitoring armored optical cable along with time is projected onto the monitored rock mass plane distribution diagram according to the actual distribution position of the change rate data;
s6: before the monitored rock mass is locally subjected to rock burst, the rock mass in a local or section begins to crack or break under the influence of local accumulation and concentration of underground ground stress on the rock mass, so that micro-seismic events distributed along the range of the broken rock mass are induced; at the moment, the monitoring armored optical cable arranged along the monitoring rock body can monitor and record seismic wave signals of the micro seismic events through a multi-channel broadband distributed optical fiber sound wave and strain sensing modulation and demodulation system, and transmits the recorded micro seismic data to a real-time data recording and processing computer system of a monitoring field in real time;
s7: according to the difference of the travel time of longitudinal waves and transverse waves of detected microseism event signals reaching detection points distributed on a monitoring armored optical cable, the coordinate position of each detection point and the longitudinal wave and transverse wave speeds of a monitored rock body in a real-time data recording and processing computer system of a monitoring site, the position coordinate of a specific breaking point on the rock body inducing the microseism event and the occurrence time of the microseism event can be calculated through inversion, and the size of the rock body breaking or the energy of the microseism event induced by the rock body breaking can be calculated through the amplitude (amplitude) of the recorded microseism event signals;
s8: displaying the distribution positions of the strain, strain rate, slow displacement and microseism event, the energy level and other results of the rock mass on the monitoring line or monitoring surface of the monitoring armored optical cable in real time on a screen of a real-time data recording and processing computer system on the monitoring site;
s9: according to the relatively concentrated distribution position of the large-magnitude strain, the rapid strain rate, the slow displacement superposition and the micro-seismic event which locally occur along the monitored rock mass of the armored optical cable and the trend that the energy thereof gradually increases, the local position or the specific section or interval of the rock mass which is likely to generate rock burst is determined, early warning information or forecast is timely sent out, and the local position or the specific section of the rock burst which is likely to generate on the rock mass is immediately processed or reinforced in advance.
The invention can measure and monitor the local strain, displacement, rupture and induced microseism events on the supporting rock mass or the mountain or the excavation working surface of the ore body at the top and two sides of the tunnel in real time, and can early warn or process or reinforce the local position or the specific section of the rockburst possibly occurring on the monitored rock mass in advance.
Drawings
FIG. 1 is a schematic diagram of the arrangement mode of the monitoring armored cable on a tunnel rock body.
FIG. 2 is a schematic view of the arrangement of the monitoring armored cable on the working surface of the mountain excavation.
Detailed Description
The following description of the embodiments of the present invention is provided to facilitate the understanding of the present invention by those skilled in the art, but it should be understood that the present invention is not limited to the scope of the embodiments, and it will be apparent to those skilled in the art that various changes may be made without departing from the spirit and scope of the invention as defined and defined in the appended claims, and all matters produced by the invention using the inventive concept are protected.
The rock burst monitoring system based on distributed optical fiber sensing comprises a plurality of monitoring armored optical cables 2, a multi-channel wide-frequency distributed optical fiber sound wave and strain sensing modulation and demodulation system 4 and a real-time data recording, storage and processing computer system 5;
as shown in fig. 1, the monitoring armored optical cable 2 is fixedly installed along the supporting rock mass or the supporting wall body at the top and two sides of the tunnel 1 which is being excavated or tunneled or is finished;
or as shown in fig. 2, the device is fixedly arranged on a working face 7 excavated or excavated along a mountain or an ore body 6;
the real-time data recording, storing and processing computer system 5 is connected with the multi-channel wide-frequency distribution type optical fiber sound wave and strain sensing modulation and demodulation system 4 and is used for recording, storing, processing and displaying results of strain, strain rate, displacement superposition, microseism events, energy and the like of a rock body on a monitoring line or a monitoring surface of the armored optical cable in real time.
The monitoring armored optical cable 2 is an armored optical cable wound in a spiral shape.
Each monitoring armored optical cable 2 is parallel to the extending direction of the tunnel 1 or the spreading direction of the working surface 7;
the distance between the adjacent monitoring armored optical cables 2 is not more than 1 meter; the length of each monitoring armored cable 2 covers the entire length of the tunnel 1 or the entire length of the working face 7.
Firstly, supporting a rock mass or a supporting wall body along the top and two sides of a tunnel 1 in the extending direction, or along the spreading direction of a working face 7, digging shallow trenches which are parallel to each other in advance, wherein the shallow trenches are 2 cm in width and 5 cm in depth, placing a monitoring armored optical cable 2 in the shallow trenches, fixing the monitoring armored optical cable 2 on the tunnel 1 or the working face 7 by using cement, and fixing the monitoring armored optical cable 2 on the tunnel 1 or the working face 7 by using densely distributed metal staples, so that the monitoring armored optical cable 2 has good adherent coupling with the rock mass or the wall body to be monitored. When a rock mass is supported or supported on the top and two sides of a tunnel 1 or on a supporting wall body, or when a large amount of induced micro-seismic events such as rock mass strain, deformation, displacement, rupture and a large amount of induced micro-seismic events occur due to the accumulation and concentration of ground stress on a working face 7 at a local position or a specific section, a monitoring armored optical cable 2 tightly coupled with the rock mass can be stretched or compressed along with the strain, deformation, displacement, rupture and a large amount of induced micro-seismic events to generate strain and deformation, at the moment, the phase of backward Rayleigh scattering light of an optical fiber stretching or compressing strain and a deformation part in the monitoring armored optical cable 2 can be changed along with the stretching or compressing of the optical fiber, a multi-channel wide-frequency distribution type optical fiber sound wave and strain sensing modulation and demodulation system 4 connected with the head end of the monitoring armored optical cable 2 is monitored, and a computer system 5 and a data processing and interpretation software, the strain, deformation, displacement and rupture of the rock mass on the monitoring line or monitoring surface along the monitoring armored optical cable 2 and the quantity, distribution position range and energy of the micro-seismic events can be calculated according to the phase change, and the specific accurate parts of the optical fiber, namely the positions or sections of the rock mass with strain, deformation, displacement, rupture and micro-seismic events, of the optical fiber can be easily determined according to the arrival time of the backward Rayleigh scattering light and the propagation speed of the light in the optical fiber.
After all the monitoring armored optical cables 2 are installed and fixed by cement or staple bolts at equal intervals along the extending direction of the tunnel 1 or the spreading direction of the working face 7, the tail end of the monitoring armored optical cable 2 is subjected to special technical treatment, such as installation of an extinction device or knotting of optical fibers, so as to eliminate strong reflection signals of the optical fibers at the tail end point, and finally the head end of the monitoring armored optical cable 2 is directly connected to the multichannel broadband distributed optical fiber sound wave and strain sensing modulation and demodulation system 4; the multichannel broadband distributed optical fiber sound wave and strain sensing modulation and demodulation system 4 is connected to a real-time data recording, storing and processing computer system 5 of a monitoring site, displays information such as slow strain, superimposed displacement and micro-seismic event position and energy of a rock mass on a monitoring line or a monitoring excavation working surface along the monitoring armored optical cable 2 in real time, and provides real-time rock burst risk monitoring and early warning information for a tunnel or mountain or ore body construction site.
The data acquisition and processing method of the distributed optical fiber sensing-based rock burst monitoring system comprises the following steps:
s1: the monitoring armored optical cables 2 are installed and fixed on the monitored rock mass through cement or staple bolts and are connected to the multichannel broadband distributed optical fiber sound wave and strain sensing modulation and demodulation system 4, the multichannel broadband distributed optical fiber sound wave and strain sensing modulation and demodulation system 4 is started, and phase change information of backscattered Rayleigh light, which is transmitted to the multichannel broadband distributed optical fiber sound wave and strain sensing modulation and demodulation system 4 by each monitoring armored optical cable 2, is continuously measured and recorded;
s2: comparing and analyzing the phase data of the backscattered Rayleigh light recorded by each measurement with the phase data of the backscattered Rayleigh light recorded in the front;
s3: when the phase data of the back scattering Rayleigh light recorded by the two measurements have difference or change at a certain position of the monitoring armored optical cable, the phase difference exclusive-or change data is converted into the strain or displacement data of the optical fiber through the multi-channel wide-frequency distribution type optical fiber sound wave and phase data processing software arranged in the strain sensing modulation and demodulation system 4, and then the strain or displacement data detected by the monitoring armored optical cable 2 is transmitted to a real-time data recording, storing and processing computer system 5 on a monitoring site;
s4: after receiving the strain or displacement data along each monitoring armored optical cable 2 transmitted from the multichannel broadband distributed optical fiber sound wave and strain sensing modulation and demodulation system 4, the real-time data recording, storing and processing computer system 5 projects the data of the strain or displacement of the rock mass on each monitoring armored optical cable 2 onto the rock mass plane layout to be monitored according to the actually laid position of the data;
s5: calculating time differential (first derivative) of the rock mass strain data on each monitoring armored optical cable 2 to obtain the change rate of the rock mass strain data on each monitoring armored optical cable 2 along with time, and projecting the change rate data of the rock mass strain data on each monitoring armored optical cable 2 along with time onto the monitored rock mass plane distribution map according to the actual distribution position of the change rate data;
s6: before the monitored rock mass is locally subjected to rock burst, the monitored rock mass locally or a section begins to crack or break under the influence of local accumulation and concentration of underground ground stress on the rock mass, so that micro-seismic events distributed along the range of the breaking rock mass are induced. At the moment, the monitoring armored optical cable 2 arranged along the monitoring rock body can monitor and record seismic wave signals of the micro seismic events through a multi-channel wide-frequency distribution type optical fiber sound wave and strain sensing modulation and demodulation system 4, and transmits the recorded micro seismic data to a real-time data recording, storing and processing computer system 5 of a monitoring site in real time;
s7: according to the difference of the travel time of longitudinal waves and transverse waves of detected microseism event signals reaching detection points distributed on the monitoring armored optical cable 2, the coordinate position of each detection point and the longitudinal wave and transverse wave speeds of a monitored rock mass in the computer system 5, the position coordinate of a specific breaking point on the rock mass inducing the microseism event and the occurrence time of the microseism event can be calculated through inversion, and the size of rock mass breaking or the energy of the microseism event induced by the rock mass breaking can be calculated through the amplitude (amplitude) of the recorded microseism event signals;
s8: displaying the results of strain, strain rate, slow displacement, distribution position of micro-seismic events, energy magnitude and the like of rock mass on a monitoring line or monitoring surface along the monitoring armored optical cable 2 in real time on a screen of a real-time data recording, storing and processing computer system 5 on a monitoring site;
s9: according to the relatively concentrated distribution position of the large-magnitude strain, the rapid strain rate, the slow displacement superposition and the micro-seismic event which locally appear along the monitored rock mass of the armored optical cable 2 and the trend that the energy thereof gradually increases, the local position or the specific section or interval of the rock mass which is likely to generate rock burst is determined, early warning information or forecast is timely sent out, and the local position or the specific section of the rock burst which is likely to generate on the rock mass is immediately processed or reinforced in advance.
Claims (8)
1. The rock burst monitoring system based on distributed optical fiber sensing is characterized by comprising a plurality of monitoring armored optical cables (2), a multi-channel wide-frequency distributed optical fiber sound wave and strain sensing modulation-demodulation system (4) and a real-time data recording, storing and processing computer system (5), wherein the monitoring armored optical cables (2) are fixedly installed on a supporting rock mass or a supporting wall body along the top and two sides of an excavation or tunneling or finished tunnel (1) or on a working face (7) of excavation or excavation along a mountain or an ore body (6); one ends of the monitoring armored optical cables (2) are connected with a multi-channel broadband distributed optical fiber sound wave and strain sensing modulation and demodulation system (4), and the multi-channel broadband distributed optical fiber sound wave and strain sensing modulation and demodulation system (4) is connected with a real-time data recording, storing and processing computer system (5).
2. The rock burst monitoring system based on distributed optical fiber sensing of claim 1, wherein the monitoring armored optical cable (2) is an armored optical cable wound in a spiral shape.
3. A rock burst monitoring system based on distributed optical fiber sensing according to claim 1, characterized in that a plurality of said monitoring armored optical cables (2) are parallel to the extending direction of the tunnel (1) or the spreading direction of the working face (7).
4. The distributed optical fiber sensing-based rock burst monitoring system according to claim 1, wherein the distance between adjacent monitoring armored optical cables (2) is not more than 1 m; the length of each monitoring armored cable (2) covers the length of the whole tunnel (1) or the length of the whole working face (7).
5. A rock burst monitoring system based on distributed optical fiber sensing according to claim 1, characterized in that the monitoring armored optical cable (2) is fixed by cement or staple, fixed on the supporting rock mass or supporting wall at the top and two sides of the tunnel (1), or fixed on the working face (7).
6. The rock burst monitoring system based on distributed optical fiber sensing of claim 1, characterized in that the other end (tail end) of all monitoring armored optical cables (2) is provided with a light extinction device.
7. A rock burst monitoring system based on distributed optical fiber sensing according to claim 6, characterized in that the light extinction device is a light extinction device installed at the tail end of the monitoring armored optical cable (2) or the tail end of the optical fiber is knotted to eliminate the strong reflection signal of the optical fiber at the tail end point.
8. The data acquisition and processing method of the rock burst monitoring system based on the distributed optical fiber sensing is characterized by comprising the following steps of:
s1: the monitoring armored optical cables (2) are well installed and fixed on a monitored rock body through cement or staples and are connected to the multichannel broadband distributed optical fiber sound wave and strain sensing modulation and demodulation system (4), the multichannel broadband distributed optical fiber sound wave and strain sensing modulation and demodulation system (4) is started, and phase change information of backscattered Rayleigh light, which is transmitted to the multichannel broadband distributed optical fiber sound wave and strain sensing modulation and demodulation system (4) by each monitoring armored optical cable (2), is continuously measured and recorded;
s2: comparing and analyzing the phase data of the backscattered Rayleigh light recorded by each measurement with the phase data of the backscattered Rayleigh light recorded in the front;
s3: when the phase data of the back scattering Rayleigh light, which are measured and recorded twice, are different or changed at a certain position of the monitoring armored optical cable, the phase difference exclusive-or change data is converted into the strain or displacement data of the optical fiber through phase data processing software which is arranged in a multi-channel wide-frequency distribution type optical fiber sound wave and strain sensing modulation and demodulation system (4), and then the strain or displacement data detected by the monitoring armored optical cable (2) is transmitted to a real-time data recording, storing and processing computer system (5) of a monitoring site;
s4: after receiving strain or displacement data along each monitoring armored optical cable (2) transmitted from the multichannel broadband distributed optical fiber sound wave and strain sensing modulation and demodulation system (4), the real-time data recording, storing and processing computer system (5) projects the data of the strain or displacement of the rock mass on each monitoring armored optical cable (2) onto the rock mass plane distribution diagram monitored by the monitoring armored optical cable according to the actually distributed position of the data;
s5: calculating time differential of the data of the rock mass strain on each monitoring armored optical cable (2), obtaining the change rate of the rock mass strain data on each monitoring armored optical cable (2) along with time, and projecting the change rate data of the rock mass strain data on each monitoring armored optical cable (2) along with time onto the monitored rock mass plane distribution diagram according to the actual distribution position of the change rate data;
s6: before the monitored rock mass is locally subjected to rock burst, the monitored rock mass locally or locally is influenced by accumulation and concentration of underground ground stress, the monitored rock mass locally or locally begins to crack or break, and accordingly microseismic events distributed along the range of the breaking rock mass or the area are induced; at the moment, the monitoring armored optical cable (2) arranged along the monitoring rock body can monitor and record seismic wave signals of the micro seismic events through a multi-channel wide-frequency distribution type optical fiber sound wave and strain sensing modulation-demodulation system (4), and transmits the recorded micro seismic data to a real-time data recording, storing and processing computer system (5) of a monitoring site in real time;
s7: according to the difference of the travel time of longitudinal waves and transverse waves of detected microseism event signals reaching detection points distributed on a monitoring armored optical cable (2) in a real-time data recording, storing and processing computer system (5) on the monitoring site, the coordinate position of each detection point and the longitudinal wave and transverse wave speeds of a monitored rock mass, the position coordinate of a specific breaking point on the rock mass inducing the microseism event and the occurrence time of the microseism event can be calculated through inversion, and the size of rock mass breakage or the energy of the microseism event induced by the rock mass can be calculated through the recorded amplitude of the microseism event signals;
s8: the results of strain, strain rate, slow displacement, distribution position of micro-seismic events, energy magnitude and the like of the rock mass on the monitoring line or monitoring surface along the monitoring armored optical cable (2) are displayed on a screen of a real-time data recording, storing and processing computer system (5) on the monitoring site in real time;
s9: according to the superposition result of large-magnitude strain, rapid strain rate and slow displacement which locally appear on the monitored rock mass along the monitoring armored optical cable (2), the relative concentrated distribution position of the micro-seismic event and the trend that the energy thereof gradually increases, the local position or the specific section or interval of the rock mass which is likely to generate rock burst is determined, early warning information or forecast is timely sent out, and the local position or the specific section of the rock burst which is likely to generate on the rock mass is immediately processed or reinforced in advance.
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| CN112785815A (en) * | 2021-01-27 | 2021-05-11 | 哈尔滨工业大学 | Surge monitoring device and method based on distributed optical fiber sensing technology |
| CN113031061A (en) * | 2021-04-02 | 2021-06-25 | 中油奥博(成都)科技有限公司 | Gasification cavity boundary identification method |
| CN116950720A (en) * | 2023-07-27 | 2023-10-27 | 中国矿业大学 | Stress wave induced roadway instability fracture field and three-dimensional strain field monitoring system and method |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN112785815A (en) * | 2021-01-27 | 2021-05-11 | 哈尔滨工业大学 | Surge monitoring device and method based on distributed optical fiber sensing technology |
| CN112785815B (en) * | 2021-01-27 | 2024-05-28 | 哈尔滨工业大学 | Surge monitoring device and method based on distributed optical fiber sensing technology |
| CN113031061A (en) * | 2021-04-02 | 2021-06-25 | 中油奥博(成都)科技有限公司 | Gasification cavity boundary identification method |
| CN116950720A (en) * | 2023-07-27 | 2023-10-27 | 中国矿业大学 | Stress wave induced roadway instability fracture field and three-dimensional strain field monitoring system and method |
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