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According to the specific geological condition, analyzed the stress distribution of the overlying strata, the displacement of pressure released seam, thickness variation and the distribution of plastic zones by FLAC 3D software to simulate mining of the long-distance lower protective seam. The research results show that the distribution of vertical stress appears as a "Double-hump" within the pressure-relief range of the protected coal seam and the swelling deformation curve of coal bodies takes an "M" shape. The swelling is divided into initial swelling, swelling increase and swelling compression stability. The maximum swelling ratio of the pressure released seam is 1.84%, protection angle of the lower protective coal seam along the strike direction is about 55°, protection angle below the dip direction is about 50°, protection angle above the dip direction is about 55°, and the coal seam compression zone resembles a "U" shape.

Fiber optic sensors (FOS) for vibration monitoring of smart structures have certain advantages over conventional strain gage based sensors due to electromagnetic environment insensitivity and high response bandwidth. During the present study, a spatially integrating fiber optic sensor was used for vibration monitoring. It is based on the concept that the optimal placement of the sensing element can be sought by using a priori knowledge of the mode shapes of the structure. The applicability ofthis approach to polarimetric optical fibers is described. The acquired integrating FOS signal was used to sense and control the vibration of an eiectrorheoiogicai adaptive structure subjected to a random external excitation.

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