Axisymmetrical analytical solution for vertical vibration of end-bearing pile in saturated viscoelastic soil layer

2010 ◽  
Vol 31 (2) ◽  
pp. 193-204 ◽  
Author(s):  
Xiao Yang ◽  
Yuan Pan
2012 ◽  
Vol 157-158 ◽  
pp. 419-423
Author(s):  
Ya Peng Zhang ◽  
Feng Gao

Considering the rheological characteristics of soil, think the fractional maxwell with viscoelastic model can be described, the fractional maxwell model into integral form of saturated soft soil layer, the one dimensional compression, through the Laplace transform problems get instantaneous loading and single stage, the analytical solution of the loading conditions.


Author(s):  
Vladimir S. Utkin

Introduction. The behavior of end-bearing piles in the foundation soil and the methodology for their reliability analysis, treated as operational safety measures applicable to a separate bearing element of a pile foundation, need clarification and further development. The weakness of the established reliability analysis methodology, focused on the bearing capacity of the foundation soil, is its failure to take account of each case of the soil behavior above rock or low compressibility soils pursuant to Construction rules and regulations 24.13330.2011. Taking account of the bearing capacity of this soil layer in respect of the load accommodation by an end-bearing pile (taking account of the pile weight) may improve its reliability by the criterion of the bearing capacity in combination with the soil behavior below the bottom tip of a pile. Nizhne-Suyanskiy Waterworks Facility had the mission to solve water household, energy and socio-economic problems. Materials and methods. The author analyzed piles made of any applicable materials; their reliability analysis methods are based on the possibility theory due to the limited amount of statistical information on controllable parameters to be entered into the limit state design model to verify the bearing capacity of the foundation soil. Results. The author presents the design formula to identify the parameters ensuring reliable failure-free behavior of an end-bearing pile in the foundation soil and in respect of the soil bearing capacity. The pile reliability analysis performed in respect of its bearing capacity (and focused on the strength of the pile material) is provided in the references section. The author uses two performance criteria to analyze the reliability of an end-bearing pile, given that an end-bearing pile is analyzed as a consistent mechanical system in terms of the reliability theory. Conclusions. The author has developed a methodology used to analyze the reliability of end-bearing piles. It is focused on the bearing capacity of the foundation soil below the bottom tip of a pile and along its length with a view to the quantitative assessment of its safe performance at the stage of design of a facility that has a piled footing; the groundwork has been laid for further research into the behavior of end-bearing piles and for the development of design regulations applicable to various types of piles that may differ in material, behavior, sinking techniques, etc.


Processes ◽  
2018 ◽  
Vol 7 (1) ◽  
pp. 5 ◽  
Author(s):  
Minghua Huang ◽  
Dun Li

The consolidation process of soil stratum is a common issue in geotechnical engineering. In this paper, the two-dimensional (2D) plane strain consolidation process of unsaturated soil was studied by incorporating vertical impeded drainage boundaries. The eigenfunction expansion and Laplace transform techniques were adopted to transform the partial differential equations for both the air and water phases into two ordinary equations, which can be easily solved. Then, the semi-analytical solutions for the excess pore-pressures and the soil layer settlement were derived in the Laplace domain. The final results in the time domain could be computed by performing the numerical inversion of Laplace transform. Furthermore, two comparisons were presented to verify the accuracy of the proposed semi-analytical solutions. It was found that the semi-analytical solution agreed well with the finite difference solution and the previous analytical solution from the literature. Finally, the 2D plane strain consolidation process of unsaturated soil under different drainage efficiencies of the vertical boundaries was illustrated, and the influences of the air-water permeability ratio, the anisotropic permeability ratio and the spacing-depth ratio were investigated.


2012 ◽  
Vol 170-173 ◽  
pp. 1142-1146
Author(s):  
Min Jie Wen ◽  
Hui Tuan He

Regarding the soil skeleton as viscoelastic medium with fractional derivative constitutive behavior, the influences of the soil skeleton viscosity and the soil layer thickness of saturated fractional derivative viscoelastic soil layer on the vertical vibration amplification coefficient is studied in the frequency domain by using the theory of Biot and one dimensional wave. The analytical expressions of the displacement, stress and pore water pressure of saturated soil layer are obtained by decoupling dynamic control equations and bounding the soil layer boundary conditions. The influences of physical and geometrical parameters of the saturated soil on vertical vibration amplification are investigated, and it is revealed that the vertical vibration amplification of the saturated classic elastic, fractional derivative type viscoelastic saturated soil and saturated classic viscoelastic soil are different when the soil layer thickness are changed; the material parameters of the fractional derivative model have great influences on the vertical vibration amplification coefficient.


2006 ◽  
Vol 51 (4) ◽  
pp. 626-641 ◽  
Author(s):  
EVANGELOS AKYLAS ◽  
ANTONIS D. KOUSSIS ◽  
ATHANASIOS N. YANNACOPOULOS

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Wenbing Wu ◽  
Guosheng Jiang ◽  
Bin Dou ◽  
Chin Jian Leo

Based on complex stiffness transfer model, the vertical vibration of tapered pile embedded in layered soil is theoretically investigated by considering the compacting effect of the soil layer surrounding the tapered pile in the piling process. Allowing for the stratification of the surrounding soil and variable crosssection of the tapered pile, the pile-soil system is discretized into finite segments. By virtue of the complex stiffness transfer model to simulate the compacting effect, the complex stiffness of different soil segments surrounding the tapered pile is obtained. Then, substituting the complex stiffness into the vertical dynamic governing equation of tapered pile, the analytical solution of vertical dynamic impedance of tapered pile under vertical exciting force is derived by means of the Laplace technique and impedance function transfer method. Based on the presented solutions, the influence of compacting effect of surrounding soil on vertical dynamic impedance at the pile head is investigated within the low frequency range concerned in the design of dynamic foundation.


2016 ◽  
Vol 53 (12) ◽  
pp. 2030-2038 ◽  
Author(s):  
Ibrahim Mashhour ◽  
Adel Hanna

Collapsible soils may experience sudden and excessive settlement when inundated. The use of pile foundations that penetrate the collapsible soil layer to reach a firm stratum is widely used in practice. However, when the ground is inundated, large and sudden settlement of the surrounding soil may take place, causing negative skin friction on the pile’s shaft, which may lead to catastrophic failure. In the literature, research dealing with negative skin friction for piles in collapsible soil is lagging due to the complexity of modeling collapsible soil analytically. Alternatively, results of sophisticated experimental investigation may produce valuable information to predict the negative skin friction and accordingly the drag load on these piles. This paper presents the results of an experimental investigation on a single end-bearing pile in collapsible soil. The investigation is tailored to measure the soil collapse before and during inundation and the associated drag load on the pile. The theory proposed by Hanna and Sharif in 2006 for predicting negative skin friction on piles due to consolidation of the surrounding soft clay was extended to predict the negative skin friction for these piles in collapsible soils. A proposed design procedure is presented.


2019 ◽  
Vol 2019 ◽  
pp. 1-18
Author(s):  
Lu Cao ◽  
Bin Zhou ◽  
Qiang Li ◽  
Weiwei Duan ◽  
Wenli Shu

A frozen soil is a multiphase medium composed of solid particles, ice, and water, and the cementation between the solid particles and ice strengthens with a decrease in temperature. Based on the theory of a composite solid-state saturated porous medium, a uniform solution for the vertical vibration of an end-bearing pile in a frozen soil is derived analytically. The axial displacements under impact loading in the time domain are calculated by using the numerical inverse transformation technique. The solution can degenerate into an end-bearing pile in a saturated soil layer as the temperature approaches the freezing point. If the cementation between the solid particles and ice is ignored, the amplitude of the displacement will be overestimated. The numerical results show that temperature has a significant impact on the dynamic responses of the pile due to variation of the ice content and, consequently, of the cementation between solid particles and ice.


2018 ◽  
Vol 14 (10) ◽  
pp. 155014771880671 ◽  
Author(s):  
Wenbing Wu ◽  
Mengfan Zong ◽  
M Hesham El Naggar ◽  
Guoxiong Mei ◽  
Rongzhu Liang

In this article, the exponentially time-growing drainage boundary is introduced to study the one-dimensional consolidation problem of double-layered soil. First, the one-dimensional consolidation equations of soil underlying a time-dependent loading are established. Then, the analytical solution of excess pore water pressure and average consolidation degree is obtained by utilizing the method of separation of variables when the soil layer is separately undergone instantaneous load and single-stage load. The validity of the present solution is proven by the comparison with other existing analytical solution. Finally, the influence of soil properties and loading scheme on the consolidation behavior of soil is investigated in detail. The results indicate that, the present solution can be degraded to Xie’s solution utilizing Terzaghi’s drainage boundary by adjusting the interface parameter, that is to say, Xie’s solution can be regarded as a special case of the present solution. The interface parameter has a significant influence on the excess pore water pressure of soil, and the larger interface parameter means the better drainage capacity of the soil layer.


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