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Author

Lijun Yin

Bio: Lijun Yin is an academic researcher from Beijing University of Technology. The author has contributed to research in topics: Image segmentation & Slag (welding). The author has an hindex of 2, co-authored 4 publications receiving 13 citations.

Papers
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Journal ArticleDOI
TL;DR: The engineering application showed that this cutterhead vibration monitoring system can reflect the changes of the geological conditions and operating parameters, providing guidance for the TBM tunnelling.

11 citations

Journal ArticleDOI
TL;DR: In this article, a cutterhead working status monitoring system for shield TBM tunnelling was developed to monitor the working status of the cutterhead in real-time, which consists of data acquisition subsystem, control and data transmission subsystem, as well as data processing and display subsystem.
Abstract: During the shield TBM tunnelling, the working status of the cutterhead is difficult to be determined because the pressured chamber is located behind the cutterhead In this paper, a cutterhead working status monitoring system for shield TBM tunnelling was developed to monitor the working status of the cutterhead in real time The system consists of data acquisition subsystem, control and data transmission subsystem, as well as data processing and display subsystem The cutter wear, cutter rotation speed and cutterhead temperature can be monitored and transmitted to the system software through the central port by cable and wireless The system software can simultaneously display the TBM operating parameters and cutterhead working status parameters, predict the cutter life and present early warning of abnormal working status The system has been successfully applied in a shield tunnelling project Based on the analysis of the monitoring data, it was found that the normal cutter wear mainly depended on the rock abrasiveness and cutter rotation distance The difference in cutter wear rate in the different ground was more than 3 times The relative sliding between the cutter and the tunnel face was widespread The sliding distance in low-abrasive formations exceeded 1/3 of the cutter track length Under the normal tunneling conditions, the cutterhead temperature was lower than 50° The successful application shows that this system can work stably in long term under harsh work environment and provide guidance for shield TBM tunnelling

11 citations

Patent
22 Sep 2017
TL;DR: In this paper, an image segmentation method and device and a segmentation threshold value is calculated according to the two-dimensional histogram of the image, and the to-be-tested object in the image is segmented precisely through a watershed method.
Abstract: The invention discloses an image segmentation method and device and an image segmentation method and device applied to slag pieces The method comprises the steps that a grayscale average of a neighborhood of each pixel point is calculated based on a grayscale value of each pixel point in an image of a to-be-tested object; a two-dimensional histogram of the image is constructed according to the calculated grayscale value of each pixel point and the grayscale average of the neighborhood of each pixel point; an optimal segmentation threshold value is calculated according to the two-dimensional histogram of the image; the to-be-tested object in the image is segmented based on the optimal segmentation threshold value to obtain an initial segmented binary image; and the to-be-tested object in the initial segmented binary image is segmented precisely through a watershed method Through the image segmentation method and device and the image segmentation method and device applied to the slag pieces, the image can be segmented precisely

5 citations

Patent
29 Sep 2017
TL;DR: In this paper, an online analysis method and system of slag pieces is presented, which consists of the following steps: continuously photographing slag bits on a moving slag discharging belt to obtain slag piece images.
Abstract: The invention discloses an online analysis method and system of slag pieces. The method comprises the following steps: continuously photographing slag pieces on a moving slag discharging belt to obtain slag piece images; acquiring a transmission speed of the slag discharging belt and slag piece quality in real time; scanning the slag pieces on the moving slag discharging belt by pre-set frequency in real time, so as to obtain outline data of the slag pieces; analyzing the obtained slag piece images to obtain lumpiness distribution data of the obtained slag pieces and carrying out combined analysis on the transmission speed and the slag piece quality to obtain mass flow data of the slag pieces; carrying out combined analysis on the transmission speed and the outline data of the slag pieces to obtain volume flow data of the slag pieces. According to the online analysis method and system, the images of the slag pieces on the slag discharging belt, the mass flow data and the volume flow data are acquired in real time, so that continuous sampling of the slag pieces can be realized and online real-time analysis on properties of the slag pieces can be carried out; powerful guarantees are provided for optimized construction of a TBM (Tunnel Boring Machine).

5 citations


Cited by
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Journal ArticleDOI
TL;DR: The engineering application showed that this cutterhead vibration monitoring system can reflect the changes of the geological conditions and operating parameters, providing guidance for the TBM tunnelling.

11 citations

Journal ArticleDOI
TL;DR: In this paper, a field measurement of TBM vibration in changing ground conditions was carried out with accelerometers mounted on the TBM bulkhead, and the vibration characteristics and patterns under different ground conditions were compared by signal processing.
Abstract: TBM vibration is inevitable during excavation in hard rock or mixed face ground conditions (MFC) and is detrimental to equipment safety and environmental protection. However, the cutting-induced vibration can help clarify the TBM-ground interaction and provide a valuable ground identification approach. In the present investigation, a field measurement of TBM vibration in changing ground conditions was carried out with accelerometers mounted on the TBM bulkhead. The vibration characteristics and patterns under different ground conditions were compared by signal processing, and their relationships to the operating parameters were investigated. The results showed that the TBM dynamic response was highly dependent on geological conditions. In homogeneous soft ground (HSG), the magnitude of vibration was low and stable, while under the MFC, the high frequency and strong vibration occurred. The vibration waveform in the MFC had an apparent periodicity and was consistent with the cutter head rotation speed. In addition, the signal consisted of a series of periodical impulses with intervals, revealing the rock-cutting process. Since the TBM vibration was sensitive to ground changes, it could provide valuable and precise information about the cutting face ground conditions. This investigation of the relationship between the ground and vibration can provide a foundation for vibration-based ground identification, which is a potential application in simultaneously tracking geological conditions during tunneling.

10 citations

Journal ArticleDOI
TL;DR: In this paper , an original methodology of signal processing is proposed to characterize the amplitude of the particle velocities, as well as the frequency content of the signals to highlight the most energetic bands, and the levels of vibrations are also compared with the thresholds existing in various European regulations concerning the impact on neighbouring structures and the disturbance to local residents.
Abstract: Excavation with tunnel boring machine (TBM) can generate vibrations, causing damages to neighbouring buildings and disturbing the residents or the equipment. This problem is particularly challenging in urban areas, where TBMs are increasingly large in diameter and shallow in depth. In response to this problem, four experimental campaigns were carried out in different geotechnical contexts in France. The vibration measurements were acquired on the surface and inside the TBMs. These measurements are also complemented by few data in the literature. An original methodology of signal processing is proposed to characterize the amplitude of the particle velocities, as well as the frequency content of the signals to highlight the most energetic bands. The levels of vibrations are also compared with the thresholds existing in various European regulations concerning the impact on neighbouring structures and the disturbance to local residents.

4 citations

Patent
10 Jul 2018
TL;DR: In this paper, an excavated earth volume measuring and early warning system of a shield machine consisting of a weight sensor, a speed sensor, an infrared area scanner, a controller, a touch screen and a belt is presented.
Abstract: An excavated earth volume measuring and early-warning system of a shield machine comprises a weight sensor, a speed sensor, an infrared area scanning sensor, a controller, a touch screen and a belt. The weight sensor is mounted under a fixed bearing surface of the belt, a support for mounting the infrared area scanning sensor is mounted on the belt, and the infrared area scanning sensor is positioned above the belt; and the weight sensor, the speed sensor, the infrared area scanning sensor and the touch screen are connected with the controller via cables, and the controller and the touch screen are installed in a control chamber. Thus, the weight, volume and density of excavated earth can be calculated accurately in a construction site to improve excavation efficiency and safety of equipment, the system is simple in structure, easy to maintain, low in cost and capable of early warning, the working efficiency and safety of the shield machine are improved greatly, and the system is applied to the technical field of shield machine engineering.

3 citations