cable

Abstract As coal mining operations extend to greater depths, the stress regime governing the surrounding rock of roadways becomes increasingly complex. Existing support schemes, often characterized by poor structural integrity and inadequate dynamic disturbance resistance, fail to effectively control rock deformation, thereby jeopardizing mine safety. This study focuses on the transport roadway of the 2803 working face at the Hetaoyu Coal Mine. To address the deficiencies of the current support strategy, a high-prestress, flexible, impact-resistant truss cable support system was developed, building upon a conventional truss bolt framework. Through an integrated approach combining numerical simulation and in-situ field measurement, a comparative analysis was conducted to evaluate the performance of the proposed support system against the original scheme during both roadway excavation and subsequent mining activities. The results demonstrate that the optimized system effectively redistributes stress within the surrounding rock under both static and dynamic disturbance conditions, fostering the formation of a composite load-bearing structure between the support elements and the surrounding rock. Field monitoring data reveal that, compared to roadways with the original support, the application of the optimized system reduces roof convergence by approximately 41% during excavation and 38% during mining period. Furthermore, rib-to-rib convergence is effectively contained, and the roof maintains its structural integrity without fracturing or collapsing. The implementation of the optimized truss system enhances the stability of deep roadways, providing a critical guarantee for safe and efficient underground coal extraction.

matched text: “cable”

An underwater towed vehicle serves as an effective and widely applicable mobile marine observation platform. Existing towed vehicles rely heavily on cables for depth adjustment. They also suffer from poor hydrodynamic efficiency and insufficient instrument space. To address these limitations, this study developed a novel compensation control system. This system regulates the vehicle’s vertical movement and cable deployment by controlling the attack angles of its front and rear hydrofoils. The Myring profile was selected as the base design for the towed vehicle, offering excellent hydrodynamic performance, ample internal space, and cost-effectiveness. To verify the system’s reliability, critical components were meticulously designed and calibrated. Hydrodynamic simulations confirmed that adjusting the hydrofoil angle effectively controls vertical motion, with stress and deformation in the lifting mechanism and cable connectors meeting design specifications. Additionally, the overall drag resistance remains low, while the lift generated by both hydrofoils satisfies depth adjustment requirements. This research provides robust numerical foundations for developing vertical control strategies, optimizing operational conditions, and conducting subsequent sea trials of towed vehicles. Quantitative comparison with the conventional scheme indicates that the proposed structure cuts total drag by 21.6%, boosts depth adjustment efficiency by 47.3%, and achieves a 32% higher hydrofoil lift-drag ratio, accompanied by a structural safety factor of 1.8 and maximum deformation of only 1.711 mm under rated working conditions.

matched text: “cable”