"Riding mining" is a form of mining where the working face is located above the roadway and advances parallel to it.Riding mining in deep soft rock creates a particular set of problems in the roadway that in..."Riding mining" is a form of mining where the working face is located above the roadway and advances parallel to it.Riding mining in deep soft rock creates a particular set of problems in the roadway that include high stresses,large deformations,and support difficulties.Herein we describe a study of the rock deformation mechanism of a roadway as observed during riding mining in deep soft rock.Theoretical analysis,numerical simulations,and on site monitoring were used to examine this problem.The stress in the rock and the visco-elastic behavior of the rock are considered.Real time data,recorded over a period of 240 days,were taken from a 750 transportation roadway.Stress distributions in the rock surrounding the roadway were studied by comparing simulations to observations from the mine.The rock stress shows dynamic behavior as the working face advances.The pressure increases and then drops after peaking as the face advances.Both elastic and plastic deformation of the surrounding rock occurs.Plastic deformation provides a mechanism by which stress in the rock relaxes due to material flow.A way to rehabilitate the roadway is suggested that will help ensure mine safety.展开更多
A rationally designed support for deep roadways excavated in broken soft rock under high stress was investigated. The deformation and failure characteristics and the mechanism of ''yielding support'' w...A rationally designed support for deep roadways excavated in broken soft rock under high stress was investigated. The deformation and failure characteristics and the mechanism of ''yielding support'' was studied for anchor bolts and cables. The rail roadway of the 2-501 working face in the Liyazhuang Mine of the Huozhou coal area located in Shanxi province was used for field trials. The geological conditions used there were used during the design phase. The new ''highly resistant, yielding'' support system has a core of high strength, yielding bolts and anchor cables. The field tests show that this support system adapts well to the deformation and pressure in the deep broken soft rock. The support system effectively controls damage to the roadway and ensures the long term stability of the wall rock and safe production in the coal mine. This provides a remarkable economic and social benefit and has broad prospects for fur- ther application.展开更多
A real-time,long-round global positioning system (GPS) bridge-deformation monitoring technology was proposed,which processes the carrier phase of multiple GPS receivers in an operation center.It was demon- strated an ...A real-time,long-round global positioning system (GPS) bridge-deformation monitoring technology was proposed,which processes the carrier phase of multiple GPS receivers in an operation center.It was demon- strated an extended Kalman filter with triple differential ionospheric-free measurement (EKF-TIF) which can eliminate the ionospheric delay,whiten the TIF noise and optimize the results of EKF,consequently,achieves a better performance than existing real time kinematic (RTK) solution.An experiment,which takes an active ionosphere condition into consideration,proves the feasibility of this system by comparing its records to that of a traditional RTK solution,practically,the system installed on the Donghai Bridge has survived a non-break running for five months.The analysis to the monitoring records shows the system achieves the designed accu- racy and reliability.展开更多
A new asymmetric watermarking scheme is proposed in this letter. In the proposed scheme, a secret real fractional DCT-I transform and a primitive watermark are employed to generate an asymmetric watermark. The secret ...A new asymmetric watermarking scheme is proposed in this letter. In the proposed scheme, a secret real fractional DCT-I transform and a primitive watermark are employed to generate an asymmetric watermark. The secret watermark for em-bedding is derived from the primitive watermark, and is embedded in the large fractional DCT-I transformation coefficients of a cover signal. The asymmetric detection procedure is performed using a correlation test. Simulation results showed that the asymmetric detection is reliable, and that the scheme can provide minimum security.展开更多
The monitoring system for slope deformation which bases on Leica （TCA series） was researched and developed. This system consists of electronic total stations, high precision thermometer, digital barometer, photoelec...The monitoring system for slope deformation which bases on Leica （TCA series） was researched and developed. This system consists of electronic total stations, high precision thermometer, digital barometer, photoelectric frequency adjustor and other related instruments and data collection and processing software. The system can monitor a series of targets automatically to obtain accurate data of distance at predetermined time, besides, it can timely display targets＇ coordinates and deformation value, velocity, etc. in graph as well. To compare of the results of different monitoring time, we can find the problems of mine slope deformation rapidly and accurately.展开更多
An extended finite element method incorporated with the cohesive crack model(CCM-based XFEM) is developed in consideration of crack tip enrichment.It could improve the accuracy and is introduced into dam safety monito...An extended finite element method incorporated with the cohesive crack model(CCM-based XFEM) is developed in consideration of crack tip enrichment.It could improve the accuracy and is introduced into dam safety monitoring for the first time.Firstly,the proposed method is verified for a benchmark concrete beam by comparing the results with those of numerical investigations obtained by other researchers.Furthermore,it is adopted as an alternative method for building the deformation hybrid models of non-stable cracks in an arc dam,for the reason that classical FEMs are cumbersome in modeling the cohesive crack growth due to the need of remeshing the moving discontinuities.Case study proves that the fitted results of the mentioned deformation hybrid model,better than the classical statistical model,are well consistent with the measured data and reliable to forecast the development tendency of crack deformation.Therefore,the present CCM-based XFEM could provide a practical way to simulate and monitor the cracking process in concrete arch dam.展开更多
基金Supported by the National Natural Science Foundation of China (Nos. 50834005 and 51074163)the Ministry of Education Support Program for New Century Excellent of China(No. NCET-08-0837)+1 种基金the Fundamental Research Funds for the Central Universities of ChinaYouth Science and Technology Foundation of China University of Mining and Technology(No. 2010QNB25)
文摘"Riding mining" is a form of mining where the working face is located above the roadway and advances parallel to it.Riding mining in deep soft rock creates a particular set of problems in the roadway that include high stresses,large deformations,and support difficulties.Herein we describe a study of the rock deformation mechanism of a roadway as observed during riding mining in deep soft rock.Theoretical analysis,numerical simulations,and on site monitoring were used to examine this problem.The stress in the rock and the visco-elastic behavior of the rock are considered.Real time data,recorded over a period of 240 days,were taken from a 750 transportation roadway.Stress distributions in the rock surrounding the roadway were studied by comparing simulations to observations from the mine.The rock stress shows dynamic behavior as the working face advances.The pressure increases and then drops after peaking as the face advances.Both elastic and plastic deformation of the surrounding rock occurs.Plastic deformation provides a mechanism by which stress in the rock relaxes due to material flow.A way to rehabilitate the roadway is suggested that will help ensure mine safety.
基金supported by the National Natural Science Foundation of China (No. 50874103)the National Basic Research Program of China (No. 2010CB226805)+1 种基金the Natural Science Foundation of Jiangsu Province (No. BK2008135)as well as by the Open Foundation of State Key Laboratory of Geomechanics and Deep Underground Engineering (No. SKLGDUEK0905)
文摘A rationally designed support for deep roadways excavated in broken soft rock under high stress was investigated. The deformation and failure characteristics and the mechanism of ''yielding support'' was studied for anchor bolts and cables. The rail roadway of the 2-501 working face in the Liyazhuang Mine of the Huozhou coal area located in Shanxi province was used for field trials. The geological conditions used there were used during the design phase. The new ''highly resistant, yielding'' support system has a core of high strength, yielding bolts and anchor cables. The field tests show that this support system adapts well to the deformation and pressure in the deep broken soft rock. The support system effectively controls damage to the roadway and ensures the long term stability of the wall rock and safe production in the coal mine. This provides a remarkable economic and social benefit and has broad prospects for fur- ther application.
文摘A real-time,long-round global positioning system (GPS) bridge-deformation monitoring technology was proposed,which processes the carrier phase of multiple GPS receivers in an operation center.It was demon- strated an extended Kalman filter with triple differential ionospheric-free measurement (EKF-TIF) which can eliminate the ionospheric delay,whiten the TIF noise and optimize the results of EKF,consequently,achieves a better performance than existing real time kinematic (RTK) solution.An experiment,which takes an active ionosphere condition into consideration,proves the feasibility of this system by comparing its records to that of a traditional RTK solution,practically,the system installed on the Donghai Bridge has survived a non-break running for five months.The analysis to the monitoring records shows the system achieves the designed accu- racy and reliability.
基金Project (Nos. 60372076 and 60272082) supported by the National Natural Science Foundation of China
文摘A new asymmetric watermarking scheme is proposed in this letter. In the proposed scheme, a secret real fractional DCT-I transform and a primitive watermark are employed to generate an asymmetric watermark. The secret watermark for em-bedding is derived from the primitive watermark, and is embedded in the large fractional DCT-I transformation coefficients of a cover signal. The asymmetric detection procedure is performed using a correlation test. Simulation results showed that the asymmetric detection is reliable, and that the scheme can provide minimum security.
文摘The monitoring system for slope deformation which bases on Leica （TCA series） was researched and developed. This system consists of electronic total stations, high precision thermometer, digital barometer, photoelectric frequency adjustor and other related instruments and data collection and processing software. The system can monitor a series of targets automatically to obtain accurate data of distance at predetermined time, besides, it can timely display targets＇ coordinates and deformation value, velocity, etc. in graph as well. To compare of the results of different monitoring time, we can find the problems of mine slope deformation rapidly and accurately.
基金supported by the National Natural Science Foundation of China (Grant Nos. 50879024,50909041)Special Fund of State Key Laboratory of China (Grant Nos. 2009586012,2010585212) the Fun-damental Research Funds for the Central Universities (Grant Nos. 2009B08514,2010B20414)
文摘An extended finite element method incorporated with the cohesive crack model(CCM-based XFEM) is developed in consideration of crack tip enrichment.It could improve the accuracy and is introduced into dam safety monitoring for the first time.Firstly,the proposed method is verified for a benchmark concrete beam by comparing the results with those of numerical investigations obtained by other researchers.Furthermore,it is adopted as an alternative method for building the deformation hybrid models of non-stable cracks in an arc dam,for the reason that classical FEMs are cumbersome in modeling the cohesive crack growth due to the need of remeshing the moving discontinuities.Case study proves that the fitted results of the mentioned deformation hybrid model,better than the classical statistical model,are well consistent with the measured data and reliable to forecast the development tendency of crack deformation.Therefore,the present CCM-based XFEM could provide a practical way to simulate and monitor the cracking process in concrete arch dam.
