Vibration isolation using open or filled trenches Part 2: 3-D homogeneous soil
ABSTRACT The isolation of structures from ground transmitted waves by open and infilled trenches in a three-dimensional context is numerically studied. The soil medium is assumed to be elastic or viscoelastic, homogeneous and isotropic. Waves generated by the harmonic motion of a surface rigid machine foundation are considered in this work. The formulation and solution of the problem is accomplished by the boundary element method in the frequency domain. The infinite space fundamental solution is used requiring discretization of the trench surface, the soil-foundation interface and some portion of the free soil surface. The proposed methodology is first tested for accuracy by solving three characteristic wave propagation problems with known solutions and then applied to several vibration isolation problems involving open and concrete infilled trenches. Three-dimensional graphic displays of the surface displacement pattern around the trenches are also presented.
- SourceAvailable from: Mainak Majumder[Show abstract] [Hide abstract]
ABSTRACT: This paper presents the application of continuous geofoam filled barriers as vibration screening material. The numerical analysis is performed by using two-dimensional finite element method under dynamic condition considering vertically oscillated strip footing as a dynamic source. The present analysis considers the foundation bed as linearly elastic, isotropic, homogeneous and non-homogeneous soil deposit. The vertical displacement amplitudes of ground vibrations are measured at different pick-up points along the ground surface to determine the amplitude reduction factor, which is considered as a measure of the screening efficiency.Computer Methods and Recent Advances in Geomechanics, Kyoto, Japan; 09/2014
- [Show abstract] [Hide abstract]
ABSTRACT: [For parts I,II see: the last two authors and B. Dasgupta, ibid. 1, 43-63 (1986; Zbl 0614.73093), and ibid. 6, 129-142 (1990; Zbl 0725.73076).] The problem of isolating structures from surface waves by open or filled trenches under conditions of plane strain is numerically studied. The soil is assumed to be an isotropic, linear elastic or viscoelastic nonhomogeneous (layered) half-space medium. Waves generated by the harmonic motion of a rigid surface machine foundation are considered. The formulation and solution of the problem are accomplished by the frequency domain boundary element method. The Green function of Kausel-Peek-Hull for a thin layered half-space is employed and this essentially requires only a discretization of the trench perimeter and the soil-foundation interface. The proposed methodology is used for the solution of a number of vibration isolation problems and the effect of soil inhomogeneity on the wave screening effectiveness of trenches is discussed.Computational Mechanics 01/1990; 7(2). · 2.43 Impact Factor
- [Show abstract] [Hide abstract]
ABSTRACT: Field vibration tests were carried out at a proposed site for the vibration testing room, and 2D numerical analysis using finite difference tool FLAC 5.0 was performed to suggest effective vibration isolation systems. In the analysis, the numerical model is first calibrated with respect to material properties, damping value, and boundary conditions to obtain the output comparable to the field test results. The calibrated model was further used to perform a parametric study by (1) providing vibrating input motions from vibrating machines to be operated; (2) using two depths of cutoff trench; and (3) providing gravel bed, gravel bed with rubber pad, and gravel bed with rubber pad and cutoff trench to study the isolation effects. Comparing the results from the parametric studies with the human perception level of vibration, a decision on the isolation system was determined.International Journal of Geomechanics 10/2010; 11:364-369. · 1.20 Impact Factor