Real-time Monitoring Of Surrounding Rock Deformation In Deep Roadways And Accurate Intervention Decision Method Of Supporting Time

With the increasing depletion of shallow coal resources,most coal mines in central and eastern China have entered the stage of deep mining and development.Compared with the shallow part,the deformation and fracture mechanism of surrounding rock of deep roadway in coal mine is more complex under the combined action of high ground tress,high geothermal,high osmotic pressure and mining disturbance,and the engineering disaster problems such as large deformation instability are more serious.In order to realize the long-term stability of deep surrounding rock,it is necessary not only to formulate scientific and reasonable,economic and feasible support scheme,but also to monitor the internal deformation of surrounding rock after support for a long time,so as to ensure that the local fracture of surrounding rock occurs in time to take measures to strengthen support and avoid the overall instability of roadway.However,at present,there are few measuring points in the monitoring method of internal deformation of surrounding rock based on multi-point displacement meter,and it is difficult to carry out fine monitoring of internal deformation of surrounding rock.Therefore,it is impossible to quickly and accurately determine the stability of surrounding rock and put forward scientific and reasonable reinforcement support scheme.In order to solve the above problems,based on fiber sensing technology,this study developed a large-range strain sensor with weak fiber grating array,and supported the use of flameproof multi-channel demodulator for mining to achieve quasi-distributed monitoring of internal deformation of deep surrounding rock.The deformation monitoring software system of deep surrounding rock is developed to realize the real-time acquisition and visualization of surrounding rock deformation monitoring data.Then,through the analysis and summary of a large number of rock uniaxial compression test data,the mechanical state of surrounding rock with different lithology under different strains is divided.Combined with the distribution joint support theory of deep surrounding rock stability control,the accurate intervention decision method of deep surrounding rock support timing is proposed,and the real-time monitoring and support scheme decision system of deep roadway surrounding rock deformation is formed.On this basis,relying on the south wing roadway of Guqiao Coal Mine in Huainan,field industrial tests were carried out to test the accuracy and reliability of the monitoring system.The specific research contents of this paper are as follows:(1)Based on the principle of weak reflection and time division multiplexing technology of fiber grating sensing,a large-range strain sensor with weak fiber grating array is developed.Through theoretical derivation,the relationship equation between the center wavelength of weak fiber grating and strain and temperature is established.Through the indoor calibration test,the measurement performance and temperature characteristics of the weak fiber grating array sensor are tested.The calibration coefficient,range,return error,strain sensitivity and temperature sensitivity of the sensor are obtained.(2)The design principles of reliable,safe and advanced monitoring system are proposed to complete the overall structure design of the surrounding rock deformation monitoring system of deep roadway.And according to the content of the monitoring system,complete the monitoring system hardware equipment layout and software structure function design and development.Through software control,command transmission,data acquisition and other processes to ensure the normal operation of the monitoring system,the real-time monitoring of deep roadway surrounding rock is realized.(3)The uniaxial compression test data of a large number of rocks in coal mines were collected and statistically analyzed.The statistical laws of the strain values of rocks corresponding to the elasticity-damage-failure in the stress-strain curves of rocks with different lithology were mastered,and then the division methods of the elastic zone,the damage expansion zone and the fracture expansion zone of surrounding rock based on the strain data were proposed.Combined with the distribution combined support theory and support design scheme of surrounding rock control in deep roadway,the precise intervention method of surrounding rock support in deep roadway based on the range of surrounding rock fracture and expansion area was proposed.(4)Based on the south wing roadway of Huainan Guqiao Coal Mine,the field industrial test of the real-time monitoring and support scheme decision system of surrounding rock deformation in deep roadway was carried out.The installation and operation of weak fiber grating array strain sensor,weak fiber grating demodulation instrument and surrounding rock deformation monitoring software were completed.According to the strain data of roadway surrounding rock,the stability state of surrounding rock is accurately judged and the corresponding support scheme is proposed.Figure[50]table[9]reference[73]...