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Taking the 11–3106 working face of Menkeqing Coal Mine as the research background, a fracture model of the structure covered by thick and hard overburden at the 11–3106 working face was established. The mechanism of rock burst in the open roadway of narrow coal pillar with multiple key layers under the deep thick and hard roof mining condition with high strength was studied. The three-level collaborative pressure relief prevention technology of “drilling, blasting and pressuring” was proposed and applied in the field. Seismic CT, microseismic monitoring, support pressure monitoring and surface subsidence observation were used to verify the effect of pressure relief. The results show that there are high and low key layers overlying the working surface of 11–3106. When the two key layers break, the overlying rock may move in a wide range, and the surrounding rock of the open roadway is greatly affected by the dynamic load disturbance. The low bearing capacity of the narrow coal pillar makes the overburden load transfer to the solid coal side of the roadway and the stress increase on the solid coal side, which is the main area of impact initiation. Under the superposition of the lateral fixed abutment pressure and the mobile abutment pressure of the working face, the stress concentration degree of the solid coal side increases continuously. Affected by the periodic breaking of the hard roof, the “dynamic and static” loading is easy to induce the impact of the open roadway. Hard roof is not only the high static load source in the 11–3106 working face system, but also the source of strong dynamic load outside the system. For the prevention of rock burst at the 11–3106 working face, the measures should be taken from three aspects at the same time: ① the coal body is weakened to form a buffer and isolation zone for impact; ② the low pre-cracking roof is weakened to reduce the density of coal rock mass and destroy the energy storage conditions inside and outside the system; and ③ the high pre-cracking roof is artificially induced to break the key layer in the middle and high levels. The three-level collaborative pressure relief prevention and control technology of “drilling, blasting and pressuring” was developed. After the on-site implementation, the impact dynamic load caused by the breaking of high and low thick hard roof was reduced, the stress concentration in the high stress zone in the coal body was weakened, the high energy microseismic events were significantly reduced, the surrounding rock activity during the mining of working face was reduced, the compressive strength of working face roof was reduced, and the ground settlement value was increased by 200%. The results show that the three-stage coordinated pressure relief of “drilling, blasting and pressuring” has a good effect of “energy release and impact reduction”, which can provide a reference for the rock burst prevention and control of narrow coal pillar working face under similar thick hard roof conditions.

Collaborative search with multiple Autonomous Underwater Vehicles (AUVs) significantly enhances search efficiency compared to the use of a single AUV, facilitating the rapid completion of extensive search tasks. However, challenges arise in underwater environments characterized by weak communication and dynamic complexities. In large marine areas, the limited endurance of a single AUV makes it impossible to cover the entire area, necessitating a collaborative approach using multiple AUVs. Addressing the limited prior information available in uncertain marine environments, this paper proposes a map-construction method using fuzzy clustering based on regional importance. Furthermore, a collaborative search method for large marine areas has been designed using a policy-iteration-based reinforcement learning algorithm. Through continuous sensing and interaction during the marine search process, multiple AUVs constantly update the map of regional importance and iteratively optimize the collaborative search strategy to achieve higher search gains. Simulation results confirm the effective utilization of limited information in uncertain environments and demonstrate enhanced search gains in collaborative scenarios.

Due to the strong disturbance of a mining face, the surrounding rock of the withdrawal roadway is susceptible to deformation and failure, which restricts the safe and efficient evacuation of mining equipment. To resolve this longstanding technical problem in mine production, an engineering investigation, numerical simulation, theoretical analysis, and other research methodologies were conducted in this study. Furthermore, the influence mechanism of mining-induced stress on the withdrawal roadway was revealed, the anti-disturbance principles of thick-layer anchorage of roadway roofs were elucidated, and a novel double-layer flexible support technique was proposed. The front abutment pressure, stress superposition, damage accumulation of the surrounding rock, and the fluctuation of mining-induced stress are the primary factors contributing to the significant deformation of the surrounding rock in a withdrawal roadway. However, the fluctuation of mining-induced stress has usually been ignored in previous studies, and it may be the most crucial cause of the significant deformation and instability of the surrounding rock. The thickness of the anchored rock beam is the most vital factor affecting the maximum subsidence and maximum tensile stress of the roof, and increasing the thickness of the anchored rock beam can significantly improve the stability and anti-disturbance performance of the roof. In the proposed double-layer flexible supporting technique, flexible steel strands serve as the carrier, which overcomes the constraint of the roadway height on the length of roof support components. The first layer of flexible support is used to construct a thick fundamental anchorage layer, while the second layer is employed to construct a thicker reinforced anchorage layer, facilitating the effective resistance of the roof against strong mining disturbances. The effectiveness of this technique was further validated through the application of an engineering practice. The research results have reference value for solving the difficult problem of mining roadway support.