The Measurement of the Dynamic Properties for an Elastic Half-Space Medium

2005 ◽  
Author(s):  
H. R. Hamidzadeh ◽  
M. Dehghani
Keyword(s):  
Analytical Solution ◽  
Half Space ◽  
Dynamic Properties ◽  
Damping Ratio ◽  
Elastic Half Space ◽  
Laboratory Model ◽  
Rigid Base ◽  
Space Model ◽  
Frequency Responses ◽  
Soil Foundation

Reliable dynamic analysis of soil-foundation interaction requires knowledge of dynamic properties of shear modulus, Poisson’s ratio and the geometrical damping ratio of the medium. In the case of a machine foundation resting on the surface of ground it is common to assume a rigid base for the foundation and an elastic half-space model for the ground. To properly evaluate dynamic properties of medium a technique based on resonant testing in conjunction with analytical solution is adopted. In the experimental part of the analysis vertical frequency responses of different rigid square blocks individually resting on the medium are measured. These results are correlated with frequency responses computed using an established analytical solution. Analyzing this equitability of results can provide estimated values for dynamic properties of the medium. The validity of the proposed method is verified by performing experiments on laboratory model.

Dynamic Response of a Hemispherical Foundation Embedded in an Elastic Half-Space

1998 ◽  
Vol 120 (4) ◽  
pp. 343-348 ◽  
Author(s):  
C.-S. Yeh ◽  
T.-J. Teng ◽  
W.-I. Liao
Keyword(s):  
Dynamic Response ◽  
Half Space ◽  
Ground Surface ◽  
Integral Equation Method ◽  
Elastic Half Space ◽  
Least Square ◽  
Sh Waves ◽  
Soil Foundation ◽  
External Forces ◽  
Impedance Functions

The dynamic response of a massless rigid hemispherical foundation embedded in a uniform homogeneous elastic half-space is considered in this study. The foundation is subjected to external forces, moments, plane harmonic P and SH waves, respectively. The series solutions are constructed by three sequences of Lamb’s singular solutions which satisfy the traction-free conditions on ground surface and radiation conditions at infinity, automatically, and their coefficients are determined by the boundary conditions along the soil-foundation interface in the least square sense. The fictitious eigen-frequencies, which arise in integral equation method, will not appear in the numerical calculation by the proposed method. The impedance functions which characterize the response of the foundation to external harmonic forces and moments at low and intermediate frequencies are calculated and the translational and rocking responses of the foundation when subjected to plane P and SH waves are also presented and discussed in detail.

scholarly journals The use of modelling of impacts exerted by means of transport on the environment for ensuring safety

2018 ◽  
Vol 188 (2) ◽  
pp. 162-175
Author(s):  
Joanna Bril ◽  
Edward Rydygier
Keyword(s):  
Rigid Body ◽  
Half Space ◽  
Dynamic Properties ◽  
Elastic Half Space ◽  
Transport Systems ◽  
Concentrated Force ◽  
Foundation Soil ◽  
Infinite Mass ◽  
Model Research ◽  
Surface Rayleigh Wave

The article presents the model research on impacts exerted by means of transport on the structures. In modelling the dynamics of transport systems the dynamic properties of the ground forming the foundation soil for tracks or roadways have been taken into account. The ground has been modelled as an elastic half-space. The dynamics of an infinite mass band being in contact with an elastic half-space has been investigated. As part of the research on impacts exerted by means of transport on structures a model of a problem has been examined where an automotive vehicle, representing a concentrated force in motion, is in contact with a roadway described as a rigid body coupled with an elastic half-space. It has been demonstrated that a surface (Rayleigh) wave propagates in the ground, being a continuous (elastic) medium, and acts on a structure modelled as a rigid body. The research results have been presented in the form of vertical and horizontal transmittances of the ground for different frequencies of loading with different unit forces.

An Efficient Semi-Analytical Method to Compute Displacements and Stresses in an Elastic Half-Space with a Hemispherical Pit

2015 ◽  
Vol 7 (3) ◽  
pp. 295-322 ◽  
Author(s):  
Valeria Boccardo ◽  
Eduardo Godoy ◽  
Mario Durán
Keyword(s):  
Analytical Solution ◽  
Boundary Conditions ◽  
Half Space ◽  
Plane Surface ◽  
Elastic Half Space ◽  
Numerical Results ◽  
Quadratic Functional ◽  
Infinite Plane ◽  
Equilibrium Equations ◽  
Finite Element Software

AbstractThis paper presents an efficient method to calculate the displacement and stress fields in an isotropic elastic half-space having a hemispherical pit and being subject to gravity. The method is semi-analytical and takes advantage of the axisymmetry of the problem. The Boussinesq potentials are used to obtain an analytical solution in series form, which satisfies the equilibrium equations of elastostatics, traction-free boundary conditions on the infinite plane surface and decaying conditions at infinity. The boundary conditions on the free surface of the pit are then imposed numerically, by minimising a quadratic functional of surface elastic energy. The minimisation yields a symmetric and positive definite linear system of equations for the coefficients of the series, whose particular block structure allows its solution in an efficient and robust way. The convergence of the series is verified and the obtained semi-analytical solution is then evaluated, providing numerical results. The method is validated by comparing the semi-analytical solution with the numerical results obtained using a commercial finite element software.

The Improved Soil Model of Finite Compressible Layer

2012 ◽  
Vol 170-173 ◽  
pp. 64-67
Author(s):  
Li Na Yao ◽  
Guang Hua Yang ◽  
Peng Hua Wang
Keyword(s):  
Elastic Modulus ◽  
Half Space ◽  
Elastic Half Space ◽  
Foundation Settlement ◽  
Secant Modulus ◽  
Layer Model ◽  
Space Model ◽  
Soil Model ◽  
Engineering Practices

Choosing an accurate soil model is the key point in calculating the foundation settlement. The commonly used models in engineering practices are the Winkler’s model, elastic half space model and finite compressible layer model. Among these models, the finite compressible layer model is widely used in the designing of raft foundation. As the finite compressible layer model can not reflect the nature of the in situ soil and the nonlinear settlement, in this paper we try to modify the elastic modulus E by the secant modulus in order to improve the soil model of finite compressible layer.

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