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Seepage in tunnel engineering, especially in underground cable tunnels, is one of the influencing factors in tunnel safety. Seepage directly or indirectly induces many tunnel accidents. The reliable observation and reasonable identification of seepage plays an important role in ensuring the safety of a tunnel. This paper introduces an infrared thermography-based auto-inspection system for seepage in cable tunnels. The leaks whether they are detectable visually or not are identified. The leakage area is accurately calculated to make a quantitative analysis. The objective assessment documents (in PDF format) are exported and the need for skilled inspectors is reduced. The results of the field trail indicate that the automatic detection system can greatly improve detection efficiency (the detection speed is increased by 2.67 times), save manpower (it needs only one or two inspectors using this detection system instead of four inspectors using the traditional method) and material resources, and improve tunnel safety, all of which are of great importance in tunnel engineering.

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This paper presents the design and optimization of a novel MEMS tuning fork gyroscope microstructure. In order to improve the mechanical sensitivity of the gyroscope, much research has been carried out in areas such as mode matching, improving the quality factor, etc. This paper focuses on the analysis of mode shape, and effectively optimizes the decoupling structure and size of the gyroscope. In terms of structural design, the vibration performance of the proposed structure was compared with other typical structures. It was found that slotting in the middle of the base improved the transmission efficiency of Coriolis vibration, and opening arc slots between the tines reduced the working modal order and frequency. In terms of size optimization, the Taguchi method was used to optimize the relevant feature sizes of the gyroscope. Compared with the initial structure, the transmission efficiency of Coriolis vibration of the optimized gyroscope was improved by about 18%, and the working modal frequency was reduced by about 2.7 kHz. Improvement of these two indicators will further improve the mechanical sensitivity of the gyroscope.

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