It is significant to research the impact resistance properties of hydraulic support due to its key support role in the fully mechanized mining face.However,it is difficult for the entire hydraulic support to implement...It is significant to research the impact resistance properties of hydraulic support due to its key support role in the fully mechanized mining face.However,it is difficult for the entire hydraulic support to implement the impact experiment underground and analyze the response characteristic.Therefore,a dynamic impact experiment for the entire hydraulic support was proposed in this paper,where a 1:2 reducedscale model of hydraulic support was designed and its response characteristics under dynamic impact load were analyzed.Firstly,a comprehensive monitoring scheme was proposed to achieve an effective monitoring for dynamic response of hydraulic support.Secondly,a multi-scale impact experiment was carried out for the entire hydraulic support and dynamic behaviors of hydraulic support under the multi-scale impact load were revealed by experimental data.Then a dynamic impact experiment of the entire hydraulic support was simulated in ADAMS with the same experiment conditions,and the experimental and simulation data were verified mutually.Finally,the characteristics of energy conversion and dissipation of the entire experiment system after impact were analyzed.The experiment results showed that the impact resistance properties of hydraulic support largely depended on the initial support conditions and different vertical rigidities affected energy distribution proportion of the entire support system.展开更多
Full-face hard rock tunnel boring machines(TBM)are essential equipment in highway and railway tunnel engineering construction.During the tunneling process,TBM have serious vibrations,which can damage some of its key c...Full-face hard rock tunnel boring machines(TBM)are essential equipment in highway and railway tunnel engineering construction.During the tunneling process,TBM have serious vibrations,which can damage some of its key components.The support system,an important part of TBM,is one path through which vibrational energy from the cutter head is transmitted.To reduce the vibration of support systems of TBM during the excavation process,based on the structural features of the support hydraulic system,a nonlinear dynamical model of support hydraulic systems of TBM is established.The influences of the component structure parameters and operating conditions parameters on the stiffness characteristics of the support hydraulic system are analyzed.The analysis results indicate that the static stiffness of the support hydraulic system consists of an increase stage,stable stage and decrease stage.The static stiffness value increases with an increase in the clearances.The pre-compression length of the spring in the relief valve a ects the range of the stable stage of the static stiffness,and it does not a ect the static stiffness value.The dynamic stiffness of the support hydraulic system consists of a U-shape and reverse U-shape.The bottom value of the U-shape increases with the amplitude and frequency of the external force acting on the cylinder body,however,the top value of the reverse U-shape remains constant.This study instructs how to design the support hydraulic system of TBM.展开更多
Comparing with the resin bolt, the hydraulic expansion bolt has different anchoring mechanism and application advantage. According to the working mechanism of the hydraulic expansion bolt, its anchoring force is expre...Comparing with the resin bolt, the hydraulic expansion bolt has different anchoring mechanism and application advantage. According to the working mechanism of the hydraulic expansion bolt, its anchoring force is expressed in four forms including support anchoring force, tension anchoring force, expansion anchoring force and tangent anchoring force, and their values can be obtained on the basis of each calculation formula. Among them, the expansion anchoring force, which is the unique anchoring force of the hydraulic expansion bolt, can provide confining pressure to increase the strength of rock. Aiming at solving the problem of stability control in the soft rock roadway in Jinbaotun Coal Mine which has a double layer of 40 U-type sheds and cannot provide enough resistance support to control floor heave, the study reveals the mechanism of floor heave in the soft rock roadway, and designs the reasonable support parameters of the hydraulic expansion bolts. The observed results of floor convergence indicate that the hydraulic expansion bolts can prevent the development and flow of the plastic zone in the floor rock to control floor heave. Research results enrich the control technology in the soft rock roadway.展开更多
The movement of the floating connecting mechanism between a hydraulic support and scraper conveyor is space movement;thus,when the hydraulic support pushes the scraper conveyor,there is an error between the actual dis...The movement of the floating connecting mechanism between a hydraulic support and scraper conveyor is space movement;thus,when the hydraulic support pushes the scraper conveyor,there is an error between the actual distance of the scraper conveyor and the theoretical moving distance.As a result,the scraper conveyor cannot obtain the straightness requirement.Therefore,the movement law of the floating connecting mechanism between the hydraulic support and scraper conveyor is analyzed and programmed into the Unity3D to realize accurate pushing of the scraper conveyor via hydraulic support.The Coal Seam?Equipment Joint Virtual Straightening System is established,and a straightening method based on the motion law of a floating connection is proposed as the default method of the system.In addition,a straightening simulation of the scraper conveyor was performed on a complex coal seam floor,the results demonstrate that the average straightening error of the scraper conveyor is within 2-8 mm,and is in direct proportion to the fluctuation of the coal seam floor in the strike of the seam with high accuracy,the straightness of scraper conveyor is more affected by the subsidence terrain during straightening than by the bulge terrain.And some conclusions are verified by experiment.Based on the verification of the relevant conclusions,a comparison and analysis of Longwall Automation Steering Committee(LASC)straightening technology and default straightening method in the simulation system shows that the straightness accuracy of LASC straightening technology under complex floor conditions is slightly less than that of the default straightening method in the proposed system.展开更多
Hydraulic support is the primary equipment used for surrounding rock control at fully mechanized mining faces.The load,location,and attitude of the hydraulic support are important sets of basis data to predict roof di...Hydraulic support is the primary equipment used for surrounding rock control at fully mechanized mining faces.The load,location,and attitude of the hydraulic support are important sets of basis data to predict roof disasters.This paper summarized and analyzed the status of coal mine safety accidents and the primary influencing factors of roof disasters.This work also proposed monitoring characteristic parameters of roof disasters based on support posture-load changes,such as the support location and support posture.The data feature decomposition method of the additive model was used with the monitoring load data of the hydraulic support in the Yanghuopan coal mine to effectively extract the trend,cycle period,and residuals,which provided the period weighting characteristics of the longwall face.The autoregressive,long-short term memory,and support vector regression algorithms were used to model and analyze the monitoring data to realize single-point predictions.The seasonal autoregressive integrated moving average(SARIMA)and autoregressive integrated moving average(ARIMA)models were adopted to predict the support cycle load of the hydraulic support.The SARIMA model is shown to be better than the ARIMA model for load predictions in one support cycle,but the prediction effect of these two algorithms over a fracture cycle is poor.Therefore,we proposed a hydraulic support load prediction method based on multiple data cutting and a hydraulic support load template library.The constructed technical framework of the roof disaster intelligent prediction platform is based on this method to perform predictions and early warnings of roof disasters based on the load and posture monitoring information from the hydraulic support.展开更多
基金supported by National Key R&D Program of China for the 13th Five-Year Plan(No.2017YFC0603005)National Natural Science Foundation of China(Nos.51874174and 51834006)。
文摘It is significant to research the impact resistance properties of hydraulic support due to its key support role in the fully mechanized mining face.However,it is difficult for the entire hydraulic support to implement the impact experiment underground and analyze the response characteristic.Therefore,a dynamic impact experiment for the entire hydraulic support was proposed in this paper,where a 1:2 reducedscale model of hydraulic support was designed and its response characteristics under dynamic impact load were analyzed.Firstly,a comprehensive monitoring scheme was proposed to achieve an effective monitoring for dynamic response of hydraulic support.Secondly,a multi-scale impact experiment was carried out for the entire hydraulic support and dynamic behaviors of hydraulic support under the multi-scale impact load were revealed by experimental data.Then a dynamic impact experiment of the entire hydraulic support was simulated in ADAMS with the same experiment conditions,and the experimental and simulation data were verified mutually.Finally,the characteristics of energy conversion and dissipation of the entire experiment system after impact were analyzed.The experiment results showed that the impact resistance properties of hydraulic support largely depended on the initial support conditions and different vertical rigidities affected energy distribution proportion of the entire support system.
基金Supported by National Key R&D Program of China(Grant No.2018YFB1702503)National Program on Key Basic Research Project of China(973 Program,Grant No.2013CB035403)Startup Fund for Youngman Research at SJTU(SFYR at SJTU)
文摘Full-face hard rock tunnel boring machines(TBM)are essential equipment in highway and railway tunnel engineering construction.During the tunneling process,TBM have serious vibrations,which can damage some of its key components.The support system,an important part of TBM,is one path through which vibrational energy from the cutter head is transmitted.To reduce the vibration of support systems of TBM during the excavation process,based on the structural features of the support hydraulic system,a nonlinear dynamical model of support hydraulic systems of TBM is established.The influences of the component structure parameters and operating conditions parameters on the stiffness characteristics of the support hydraulic system are analyzed.The analysis results indicate that the static stiffness of the support hydraulic system consists of an increase stage,stable stage and decrease stage.The static stiffness value increases with an increase in the clearances.The pre-compression length of the spring in the relief valve a ects the range of the stable stage of the static stiffness,and it does not a ect the static stiffness value.The dynamic stiffness of the support hydraulic system consists of a U-shape and reverse U-shape.The bottom value of the U-shape increases with the amplitude and frequency of the external force acting on the cylinder body,however,the top value of the reverse U-shape remains constant.This study instructs how to design the support hydraulic system of TBM.
基金support by the National Natural Science Foundation of China (No.51174195)the Fundamental Research Funds for the Central Universities of China (No.2010QNA31)
文摘Comparing with the resin bolt, the hydraulic expansion bolt has different anchoring mechanism and application advantage. According to the working mechanism of the hydraulic expansion bolt, its anchoring force is expressed in four forms including support anchoring force, tension anchoring force, expansion anchoring force and tangent anchoring force, and their values can be obtained on the basis of each calculation formula. Among them, the expansion anchoring force, which is the unique anchoring force of the hydraulic expansion bolt, can provide confining pressure to increase the strength of rock. Aiming at solving the problem of stability control in the soft rock roadway in Jinbaotun Coal Mine which has a double layer of 40 U-type sheds and cannot provide enough resistance support to control floor heave, the study reveals the mechanism of floor heave in the soft rock roadway, and designs the reasonable support parameters of the hydraulic expansion bolts. The observed results of floor convergence indicate that the hydraulic expansion bolts can prevent the development and flow of the plastic zone in the floor rock to control floor heave. Research results enrich the control technology in the soft rock roadway.
基金This research was supported by the Project funded by National Natural Science Foundation of China(Grant No.52004174)China Postdoctoral Science Foundation(No.2019M651081)+2 种基金the Key Research and Development Program of Shanxi(201903D121141)the Natural Science Foundation of Shanxi Province(201901D211022)the Scientific and Technological Innovation Programs of Higher Education Institutions in Shan Xi(No.2019L0305).
文摘The movement of the floating connecting mechanism between a hydraulic support and scraper conveyor is space movement;thus,when the hydraulic support pushes the scraper conveyor,there is an error between the actual distance of the scraper conveyor and the theoretical moving distance.As a result,the scraper conveyor cannot obtain the straightness requirement.Therefore,the movement law of the floating connecting mechanism between the hydraulic support and scraper conveyor is analyzed and programmed into the Unity3D to realize accurate pushing of the scraper conveyor via hydraulic support.The Coal Seam?Equipment Joint Virtual Straightening System is established,and a straightening method based on the motion law of a floating connection is proposed as the default method of the system.In addition,a straightening simulation of the scraper conveyor was performed on a complex coal seam floor,the results demonstrate that the average straightening error of the scraper conveyor is within 2-8 mm,and is in direct proportion to the fluctuation of the coal seam floor in the strike of the seam with high accuracy,the straightness of scraper conveyor is more affected by the subsidence terrain during straightening than by the bulge terrain.And some conclusions are verified by experiment.Based on the verification of the relevant conclusions,a comparison and analysis of Longwall Automation Steering Committee(LASC)straightening technology and default straightening method in the simulation system shows that the straightness accuracy of LASC straightening technology under complex floor conditions is slightly less than that of the default straightening method in the proposed system.
基金The study was supported by the National Natural Science Foundation of China of basic theory research on digital coal mine and intelligent mining(51834006)study on stress,cyclic osmotic pressure and corrosion coupling damage mechanism of coal pillar dam for coalmine underground reservoir(52004124)study on the progressive evolution mechanism of overburden fracture and ore pressure in fully mechanized mining with super high mining height under three field perspectives(51874175)。
文摘Hydraulic support is the primary equipment used for surrounding rock control at fully mechanized mining faces.The load,location,and attitude of the hydraulic support are important sets of basis data to predict roof disasters.This paper summarized and analyzed the status of coal mine safety accidents and the primary influencing factors of roof disasters.This work also proposed monitoring characteristic parameters of roof disasters based on support posture-load changes,such as the support location and support posture.The data feature decomposition method of the additive model was used with the monitoring load data of the hydraulic support in the Yanghuopan coal mine to effectively extract the trend,cycle period,and residuals,which provided the period weighting characteristics of the longwall face.The autoregressive,long-short term memory,and support vector regression algorithms were used to model and analyze the monitoring data to realize single-point predictions.The seasonal autoregressive integrated moving average(SARIMA)and autoregressive integrated moving average(ARIMA)models were adopted to predict the support cycle load of the hydraulic support.The SARIMA model is shown to be better than the ARIMA model for load predictions in one support cycle,but the prediction effect of these two algorithms over a fracture cycle is poor.Therefore,we proposed a hydraulic support load prediction method based on multiple data cutting and a hydraulic support load template library.The constructed technical framework of the roof disaster intelligent prediction platform is based on this method to perform predictions and early warnings of roof disasters based on the load and posture monitoring information from the hydraulic support.
