Time Effects on Settlement of Rigid Pile Composite Foundation: Simplified Models

2018 ◽  
Vol 15 (07) ◽  
pp. 1850066 ◽  
Author(s):  
Meijuan Xu ◽  
Pengpeng Ni ◽  
Guoxiong Mei ◽  
Yanlin Zhao
Keyword(s):  
Numerical Integration ◽  
Half Space ◽  
Unsaturated Soils ◽  
Pressure Coefficient ◽  
Closed Form Solution ◽  
Elastic Half Space ◽  
Composite Foundation ◽  
Model Parameters ◽  
Time Effects ◽  
Rigid Pile

The behavior of pile composite foundation is studied using the flexibility method. During the analysis, determination of the flexibility matrix (settlement) is critical. However, conventional methods of Winkler and elastic half-space foundation models are incapable of considering the time effects of soil consolidation and creep. The foundation model of Zaretsky and Tsytovich [1965] can be used to evaluate settlement for unsaturated soils, but the complexity of numerical integration over an arbitrary loading area hinders its application. In this paper, a novel scheme is proposed for numerical integration by rotating the loading surface using the equiareal transformation technique. Therefore, a simplified closed-form solution is developed to calculate time dependent settlement for foundation soils. The efficacy of the proposed technique is demonstrated using illustrative examples of an elastic half-space, a rigid raft foundation without piles, and rigid pile composite foundations with multiple piles under surface loading. Furthermore, parametric study is conducted to evaluate the sensitivity of model parameters. The permeability [Formula: see text] and Poisson’s ratio [Formula: see text] are found to be important, whereas pore pressure coefficient [Formula: see text] and degree of saturation [Formula: see text] are less significant in the calculation.

Numerical Solution of Prestressed Foundation - Subsoil Interaction Using FEM

2020 ◽  
Vol 832 ◽  
pp. 81-88 ◽  
Author(s):  
Radim Čajka ◽  
Jaroslav Navrátil
Keyword(s):  
Numerical Solution ◽  
Numerical Integration ◽  
Half Space ◽  
Structural Strength ◽  
Elastic Half Space ◽  
Isoparametric Element ◽  
Foundation Soil ◽  
Fem Model ◽  
Interaction Task ◽  
Internal Forces

This paper deals with prestressed foundation - soil interaction. For interaction task is used FEM model of thick slab with shear influence which is supported by structural strength modified elastic half-space. The calculation of deformations, internal forces and contact stresses in subsoil is performed iteratively by means of isoparametric element and numerical integration. The results of settlement and stress of non-prestressed/prestressed slab - subsoil interaction are compared on example.

Accuracy of Stress Analysis Using Numerical Integration of Elastic Half-Space

2013 ◽  
Vol 300-301 ◽  
pp. 1127-1135 ◽  
Author(s):  
Radim Čajka
Keyword(s):  
Finite Element ◽  
Stress Analysis ◽  
Numerical Integration ◽  
Half Space ◽  
Elastic Half Space ◽  
Rigidity Matrix ◽  
Interaction Solutions ◽  
Proposed Model ◽  
Isoparametric Elements

In case of constructions placed on subsoil, it is necessary to create a rigidity matrix for the element subsoil. That rigidity matrix should be then added up in respective positions with the rigidity matrix of an element. To clarify the proposed model of the subsoil, a method is derived for determination of vertical subsoil stress analysis under any shape of a slab construction by means of numerical integration and theory of isoparametric elements using the Jacobian transformation. This approach is rather original and represents the key contribution of this work in interaction solutions. Using the proposed approach, the method can be employed for any shape of a finite element.

Study on overflow problem of numerical integration for layered elastic half-space systems

2017 ◽  
Vol 19 (6) ◽  
pp. 1476-1488
Author(s):  
Yuan Pang ◽  
Peiwen Hao ◽  
Chuanchao Zheng ◽  
Haiwei Zhang ◽  
Lei Bu ◽  
...  
Keyword(s):  
Numerical Integration ◽  
Half Space ◽  
Elastic Half Space ◽  
Space Systems

Exact closed-form solutions for Lamb’s problem—III: the case for buried source and receiver

2020 ◽  
Vol 224 (1) ◽  
pp. 517-532
Author(s):  
Xi Feng ◽  
Haiming Zhang
Keyword(s):  
Closed Form ◽  
Half Space ◽  
Closed Form Solution ◽  
Time History ◽  
Natural Generalization ◽  
Elastic Half Space ◽  
Form Solution ◽  
Elementary Functions ◽  
Heaviside Step Function ◽  
Lamb’S Problem

SUMMARY In this paper, we derive the exact closed-form solution for the displacement in the interior of an elastic half-space due to a buried point force with Heaviside step function time history. It is referred to as the tensor Green’s function for the elastic wave equation in a uniform half-space, also a natural generalization of the classical 3-D Lamb’s problem, for which previous solutions have been restricted to the cases of either the source or the receiver or both are located on the free surface. Starting from the complex integral solutions of Johnson, we follow the similar procedures presented by Feng and Zhang to obtain the closed-form expressions in terms of elementary functions as well as elliptic integrals. Numerical results obtained from our closed-form expressions agree perfectly with those of Johnson, which validates our explicit formulae conclusively.

Solution of the Contact Problem of a Rigid Conical Frustum Indenting a Transversely Isotropic Elastic Half-Space

2013 ◽  
Vol 81 (4) ◽  
Author(s):  
X.-L. Gao ◽  
C. L. Mao
Keyword(s):  
Contact Problem ◽  
Closed Form ◽  
Half Space ◽  
Cone Angle ◽  
Closed Form Solution ◽  
Transversely Isotropic ◽  
Elastic Half Space ◽  
Form Solution ◽  
Potential Functions ◽  
Displacement Method

The contact problem of a rigid conical frustum indenting a transversely isotropic elastic half-space is analytically solved using a displacement method and a stress method, respectively. The displacement method makes use of two potential functions, while the stress method employs one potential function. In both the methods, Hankel's transforms are applied to construct potential functions, and the associated dual integral equations of Titchmarsh's type are analytically solved. The solution obtained using each method gives analytical expressions of the stress and displacement components on the surface of the half-space. These two sets of expressions are seen to be equivalent, thereby confirming the uniqueness of the elasticity solution. The newly derived solution is reduced to the closed-form solution for the contact problem of a conical punch indenting a transversely isotropic elastic half-space. In addition, the closed-form solution for the problem of a flat-end cylindrical indenter punching a transversely isotropic elastic half-space is obtained as a special case. To illustrate the new solution, numerical results are provided for different half-space materials and punch parameters and are compared to those based on the two specific solutions for the conical and cylindrical indentation problems. It is found that the indentation deformation increases with the decrease of the cone angle of the frustum indenter. Moreover, the largest deformation in the half-space is seen to be induced by a conical indenter, followed by a cylindrical indenter and then by a frustum indenter. In addition, the axial force–indentation depth relation is shown to be linear for the frustum indentation, which is similar to that exhibited by both the conical and cylindrical indentations—two limiting cases of the former.

Dynamical Compliance of Rectangular Foundations on an Elastic Half-Space

1963 ◽  
Vol 30 (4) ◽  
pp. 579-584 ◽  
Author(s):  
William T. Thomson ◽  
Takuji Kobori
Keyword(s):  
Half Space ◽  
Closed Form Solution ◽  
Static Problem ◽  
Elastic Half Space ◽  
Form Solution ◽  
Ground Displacement ◽  
Foundation Slab ◽  
Limiting Case ◽  
Rectangular Foundation ◽  
Zero Frequency

Equation for the compliance of the ground, considered as an elastic half-space under a rectangular foundation slab, is developed for harmonic forces normal to the ground. Displacement of the center of the slab for several rectangular shapes is evaluated numerically and plotted as a function of the frequency. A closed-form solution for the limiting case of zero frequency is shown to agree exactly with the static problem of Love [7].

The efficiency of application of virtual cross-sections method and hypotheses MELS in problems of wave signal propagation in elastic waveguides with rough surfaces

2016 ◽  
pp. 3564-3575 ◽  
Author(s):  
Ara Sergey Avetisyan
Keyword(s):  
Half Space ◽  
Cross Sections ◽  
Classical Method ◽  
Signal Propagation ◽  
Elastic Half Space ◽  
Layered Systems ◽  
Surface Layers ◽  
Inhomogeneous Surface ◽  
Wave Signal ◽  
The Impact

The efficiency of virtual cross sections method and MELS (Magneto Elastic Layered Systems) hypotheses application is shown on model problem about distribution of wave field in thin surface layers of waveguide when plane wave signal is propagating in it. The impact of surface non-smoothness on characteristics of propagation of high-frequency horizontally polarized wave signal in isotropic elastic half-space is studied. It is shown that the non-smoothness leads to strong distortion of the wave signal over the waveguide thickness and along wave signal propagation direction as well.  Numerical comparative analysis of change in amplitude and phase characteristics of obtained wave fields against roughness of weakly inhomogeneous surface of homogeneous elastic half-space surface is done by classical method and by proposed approach for different kind of non-smoothness.

Sign in / Sign up

Export Citation Format

Share Document