SUMMARYA simplified analytical method is presented for the vertical dynamic analysis of a rigid, massive, cylindrical foundation embedded in a poroelastic soil layer. The foundation is subjected to a time-harmonic vertical loading and is perfectly bonded to the surrounding soil in the vertical direction. The soil underlying the foundation base is represented by a single-layered poroelastic soil based on rigid bedrock while the soil at the side of the foundation is modeled as an independent poroelastic layer composed of a series of infinitesimally thin layers. The behavior of the soil is governed by Biot's poroelastodynamic theory and its governing equations are solved by the use of Hankel integral transform. The contact surface between the foundation base and the soil is smooth and fully permeable. The dynamic interaction problem is solved following standard numerical procedures. The accuracy of the present solution is verified by comparisons with the well-known solutions obtained from other approaches for both the elastodynamic interaction problem and poroelastodynamic interaction problem. Numerical results for the vertical dynamic impedance and response factor of the foundation are presented to demonstrate the influence of nondimensional frequency of excitation, soil layer thickness, poroelastic material parameters, depth ratio and mass ratio on the dynamic response of a rigid foundation embedded in a poroelastic soil layer.

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SUMMARYThis paper presents an analysis of the rocking vibrations of a rigid cylindrical foundation embedded in poroelastic soil. The foundation is subjected to time-harmonic rocking excitation and is perfectly bonded to the surrounding soil. The soil underlying the foundation base is represented by a homogeneous poroelastic half-space, whereas the soil along the side of the foundation is modeled as an independent poroelastic stratum composed of a series of infinitesimally thin layers. The behavior of the soil is governed by Biot's poroelastodynamic theory. The contact surface between the foundation base and the poroelastic soil is assumed to be smooth and either fully permeable or impermeable. The dynamic interaction problem is solved by employing a simplified analytical method. Some numerical results for the nondimensional rocking dynamic impedance and nondimensional angular displacement amplitude of the foundation are presented to show the effect of nondimensional frequency of excitation, poroelastic material parameters, hydraulic boundary condition, depth ratio and mass ratio of the foundation.

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Abstract-Taking 2-1 coal seam of Zhao GU second mine of Henan Coal Mine Group as the background, the article analyzed the relationship between stress of deep mining coal and rock mass and permeability, and studied the relationship between oriented flow channels namely the Gas Channels of deep mining coal and rock mass and permeability and revealed laws of the formation of the Gas Channels of the deep space mining. The research results are as follows: (1) under the impact of mining, the stress of space mining redistributes and the inner of the coal and rock mass emerges the phenomenon that cracks expanse and rupture. The channel forming at this time, in which gas flows and diffuses, is called the Gas Channel. (2) Fit out curves about stress of mining coal and rock mass and permeability in different coal and rock mass states. (3) Get the relationship between maximal and minimum permeability and distance that working face has advanced and obtain the position of permeability mutation point above the gob. (4) Gain that the permeability is related to the degree of coal and rock mass's cracks development. However, it is essentially related to stress acting on mining coal and rock mass.