Meshfree consolidation analysis of saturated porous media with stabilized conforming nodal integration formulation

Wang, Dongdong,Xie, Pinkang,Lu, Hongsheng Techno-Press 2013 Interaction and multiscale mechanics Vol.6 No.2

A strain smoothing meshfree formulation with stabilized conforming nodal integration is presented for modeling the consolidation process in saturated porous media. In the present method, nodal strain smoothing is consistently introduced into the meshfree approximation of strain and pore pressure gradient variables associated with the saturated porous media. Meanwhile, in order to achieve a consistent numerical implementation, a smoothing approximation of the meshfree shape function within a nodal representative domain is also proposed in the stiffness construction. The resulting discrete system of equations is all expressed in smoothed nodal measures that are very efficient for numerical evaluation. Subsequently the space-time fully discrete equations are further established by the generalized trapezoidal rule for time integration. The effectiveness of the proposed meshfree consolidation analysis method is systematically illustrated by several benchmark problems.

1-D Finite Element Artificial Boundary Method for Saturated Layered Half-Space Site Response under Obliquely Incident P-SV Waves

Lingwei Chen,Bo Li,Peng Li 대한토목학회 2024 KSCE Journal of Civil Engineering Vol.28 No.1

A novel finite element scheme is derived to evaluate the transient dynamic response of a multi-layered saturated porous half-space due to obliquely incident P or SV wave. The system consists of N  1 layers with different thickness and properties that overlay on a saturated half-space from which the wave is input. Biot theory is utilized to describe the mechanism of saturated poroelastic media. In this method finite computational area is truncated from the infinite domain by a horizontal artifitial boundary introduced in the underlying half-space. Wave inputting effects and absorbing boundary condition at the bounday are derived. The spatial problem is then transformed approximatedly into a one-dimensional problem based on the Snell's law. The transient 1-D problem is descritized spacially by means of FEM and solved by the standard time intergration algorithm. Numerical examples show that the proposed 1-D finite element artificial boundary method can provide accurate results for seismic performance of saturated layerd half-space under obliquely incident waves with low values of permeability or frequency content. The method is applied in site response analysis of Hong Kong-Zhuhai-Macao immersed tunnel project. By comparison with the analytical solutions, it is demonstrated for geotechnic earthquake engineering problems, site response solutions with satisfactory accuracy can be achieved by the proposed method.

Contaminant transport through porous media: An overview of experimental and numerical studies

Patil, S.B.,Chore, H.S. Techno-Press 2014 Advances in environmental research Vol.3 No.1

The groundwater has been a major source of water supply throughout the ages. Around 50% of the rural as well as urban population in the developing countries like India depends on groundwater for drinking. The groundwater is also an important source in the agriculture and industrial sector. In many parts of the world, groundwater resources are under increasing threat from growing demands, wasteful use and contamination. A good planning and management practices are needed to face this challenge. A key to the management of groundwater is the ability to model the movement of fluids and contaminants in the subsurface environment. It is obvious that the contaminant source activities cannot be completely eliminated and perhaps our water bodies will continue to serve as receptors of vast quantities of waste. In such a scenario, the goal of water quality protection efforts must necessarily be the control and management of these sources to ensure that released pollutants will be sufficiently attenuated within the region of interest and the quality of water at points of withdrawal is not impaired. In order to understand the behaviour of contaminant transport through different types of media, several researchers are carrying out experimental investigations through laboratory and field studies. Many of them are working on the analytical and numerical studies to simulate the movement of contaminants in soil and groundwater of the contaminant transport. With the advent of high power computers especially, a numerical modelling has gained popularity and is indeed of particular relevance in this regard. This paper provides the state of the art of contaminant transport and reviews the allied research works carried out through experimental investigation or using the analytical solution and numerical method. The review involves the investigation in respect of both, saturated and unsaturated, porous media.

A radial point interpolation method for 1D contaminant transport modelling through landfill liners

Praveen Kumar, R.,Dodagoudar, G.R. Techno-Press 2010 Geomechanics & engineering Vol.2 No.2

In the framework of meshfree methods, a new methodology is developed based on radial point interpolation method (RPIM). This methodology is applied to a one-dimensional contaminant transport modelling in the saturated porous media. The one-dimensional form of advection-dispersion equation involving reactive contaminant is considered in the analysis. The Galerkin weak form of the governing equation is formulated using 1D meshfree shape functions constructed using thin plate spline radial basis functions. MATLAB code is developed to obtain the numerical solution. Numerical examples representing various phenomena, which occur during migration of contaminants, are presented to illustrate the applicability of the proposed method and the results are compared with those obtained from the analytical and finite element solutions. The proposed RPIM has generated results with no oscillations and they are insensitive to Peclet constraints. In order to test the practical applicability and performance of the RPIM, three case studies of contaminant transport through the landfill liners are presented. A good agreement is obtained between the results of the RPIM and the field investigation data.

Transport of chloride through saturated soil column: An experimental study

Patil, S.B.,Chore, H.S. Techno-Press 2015 Advances in environmental research Vol.4 No.2

The groundwater is a very important part of the environment and must be protected for the benefit of the present and future generation. The contamination of soil and groundwater by chemicals has become an increasing concern in the recent past. These chemicals enter the groundwater system by a wide variety of mechanisms, including accidental spills, land disposal of domestic and industrial wastes and application of agricultural fertilizers. Once introduced into an aquifer, these contaminants will be transported by flowing groundwater and may degrade water quality at nearby wells and streams. For improving the management and protection of groundwater resources, it is important to first understand the various processes that control the transport of contaminants in groundwater. Predictions of the fate of groundwater contaminants can be made to assess the effect of these chemicals on local water resources and to evaluate the effectiveness of remedial actions. In this study, an attempt has been made to investigate the behaviour of solute transport through porous media using laboratory experiments. Sodium chloride was used as a conservative chemical in the experiment. During the experiment, pulse boundary condition and continuous boundary conditions were used. Experimental results have been presented for conservative solute transport in the sand. The pattern of the break through curve remains almost same in all the cases of varying flow rate and initial concentration of conservative chemical.

Degradation Of Oxytetracycline In Saturated Porous Media By In Situ Chemical Oxidation Using Oxygen Doped Graphitic Carbon Nitride And Peroxymonosulfate

Thanh Tuan Nguyen(NGUYEN THANH TUAN),Seok-Oh Ko(고석오),Do Gun Kim(김도군) 대한환경공학회 2021 대한환경공학회 학술발표논문집 Vol.2021 No.11

다공성 포화 매질에서 효소 중합반응을 이용한 페놀 제거

김원기(Won Gee Kim),이승목(Seung Mok Lee) 大韓環境工學會 2008 대한환경공학회지 Vol.30 No.10

Fluid-structure interaction system predicting both internal pore pressure and outside hydrodynamic pressure

Hadzalic, Emina,Ibrahimbegovic, Adnan,Dolarevic, Samir Techno-Press 2018 Coupled systems mechanics Vol.7 No.6

In this paper, we present a numerical model for fluid-structure interaction between structure built of porous media and acoustic fluid, which provides both pore pressure inside porous media and hydrodynamic pressures and hydrodynamic forces exerted on the upstream face of the structure in an unified manner and simplifies fluid-structure interaction problems. The first original feature of the proposed model concerns the structure built of saturated porous medium whose response is obtained with coupled discrete beam lattice model, which is based on Voronoi cell representation with cohesive links as linear elastic Timoshenko beam finite elements. The motion of the pore fluid is governed by Darcy's law, and the coupling between the solid phase and the pore fluid is introduced in the model through Biot's porous media theory. The pore pressure field is discretized with CST (Constant Strain Triangle) finite elements, which coincide with Delaunay triangles. By exploiting Hammer quadrature rule for numerical integration on CST elements, and duality property between Voronoi diagram and Delaunay triangulation, the numerical implementation of the coupling results with an additional pore pressure degree of freedom placed at each node of a Timoshenko beam finite element. The second original point of the model concerns the motion of the outside fluid which is modeled with mixed displacement/pressure based formulation. The chosen finite element representations of the structure response and the outside fluid motion ensures for the structure and fluid finite elements to be connected directly at the common nodes at the fluid-structure interface, because they share both the displacement and the pressure degrees of freedom. Numerical simulations presented in this paper show an excellent agreement between the numerically obtained results and the analytical solutions.

다공성 매질내의 공기압 확산에 대한 실내 배수시험과 유한요소해석 비교분석

김유성,김재홍,김태헌,이진광 한국지반공학회 2014 한국지반공학회논문집 Vol.30 No.2

3상으로 이루어진 다공성 매질 내에서 공기의 흐름을 확인하기 위해 실내시험과 수치해석 알고리즘의 비교분석을하였다. 불포화 지반내의 유체의 흐름을 확인하는 연구는 이산화탄소 지중저장을 위한 안정성 예측을 위해 중요한기초연구이다. 일반적으로 대기압에 노출되어 있는 지반공학적인 문제들은 3상 다공성 매질 내부에서 발생할 수있는 공기압을 ‘0’으로 가정하고 해석하지만, 지중 1km 지점에서의 불포화토의 거동은 기체압력을 고려하여 지반의변형과 연계해석이 필수적이다. 본 연구는 이러한 지중 깊숙한 곳에서 발생할 수 있는 불포화 지반의 거동을 해석하고자 공기압의 확산과 소산에 대한 수치해석과 실내배수시험을 비교분석하여 유한요소해석 알고리즘을 검증하고자한다.

함수다공질층의 진공건조에 관한 실험적 연구(Ⅰ)

박형진(H. J. Park),김경근(K. K. Kim),김명환(M. H. Kim) 한국마린엔지니어링학회 1996 한국마린엔지니어링학회지 Vol.20 No.5