Solution For Consolidation Research Articles

Fully transient analytical solution for solute transport in 1D deforming saturated porous media considering nonlinear compressibility and permeability

In this study, a series of analytical solutions for coupled consolidation and solute transport in 1D saturated deformable porous media considering nonlinear compressibility and permeability relationships is presented. The proposed analytical solutions consider the combined effects of consolidation, diffusion, advection, dispersion, sorption and degradation. The proposed analytical solutions are successfully validated against the experimental results of consolidation-induced solute transport tests and verified against the CST3 numerical model. The results in model verification indicate that the proposed analytical solution shows good efficiency and accuracy and the assumptions taken in deriving the analytical solution of consolidation governing equation have a limited impact on the accuracy of the proposed analytical solution. Using the verified analytical solution, a series of simulations is conducted to investigate the effects of consolidation and solute transport mechanisms (i.e., advection, dispersion, sorption and degradation) on trichloroethylene (TCE) transport through the compacted clay liner (CCL) system. The results indicate that, regardless of which solute transport mechanism is considered, the consolidation of CCL can substantially affect the TCE transport through the CCL liner system. The advection induced by the leachate head and the sorption of CCL increase the effect of consolidation on TCE transport through the CCL liner system, whereas the dispersion of TCE decreases this effect. Moreover, degradation (both the degradation of dissolved and sorbed TCE masses) can barely affect the effect of consolidation on TCE transport.

Consolidation considering increasing soil column radius for dredged slurries improved by vacuum preloading method

Soil column is often investigated in the improvement of dredged slurries. Different from the smear zone, the soil column forms gradually and has extremely low permeability. This study presents an analytical solution for soil consolidation considering the increasing radius of the soil column and time-dependent discharge capacity. Based on the solution, the influence of the radius' increase on the consolidation behavior is found significant when the soil column has low permeability and large final radius, and the increase of formation time can lead to the increase of consolidation speed and final consolidation degree.

Solution for consolidation and retrofitting a historical steel bridge

Sustainable development is a fundamental goal of the European Union and seeks to meet the needs of the present, without compromising the future. The rehabilitation of historic steel constructions and old steel bridges in service, is part of the maintenance and conservation of existing heritage, thus considering a sustainable development concept, while constituting an act of culture.In present time, in Romania there are a relatively small number of steel bridges older than 100 years, especially in Transylvania region; they can be considered "witnesses of the past". Two important aspects are highlighted: consolidation costs are lower than for a new structure and the retrofitted bridge can receive a new, modern functional role that fits functionally into the landscape. The paper is presenting a study case for an existing steel bridge build in the beginning of twentieth century (around year 1925). There are presented solution for consolidation of the bridge and retrofitting, taken into account fatigue design and structural integrity assessment. Critical flaws values were determined for each case type using the failure assessment diagrams. These values are used as limit values for fatigue analysis based on fracture mechanics principles, to determine the number of cycles for a crack to extend from initial to critical dimension, i.e. failure. For the assessment was used the code cyclic loading as a block independent iterative solver – applying the specified stress ranges sequentially line by line, repeating the entire cyclic loading - entire group of cycles for a number of blocks (one block representing all the applied cycles of stress ranges).

Semianalytical Solution for Thermal Consolidation of Viscoelastic Marine Clay with the Fractional Order Derivative

The deformation property of marine clay under a heat source has received considerable attention in the geotechnical literature. In this paper, a three‐parameter fractional order derivative model is introduced into the thermo‐hydro‐mechanical coupling governing equations with thermal filtration and thermo‐osmosis to simulate viscoelastic characteristics of marine clay. The excess pore pressure, temperature increment, and displacement of marine clay are derived by using the Laplace transform method, and the semianalytical solution for the one‐dimensional thermal consolidation in the time domain is derived by using a numerical inversion of the inverse Laplace transform. The influence of the order of the fractional derivative, material parameters, and phenomenological coefficient on thermal consolidation is investigated based on the present solutions. It is shown that the influence of the fractional derivative parameter on the excess pore pressure and displacement of marine clay depends on the properties of soil mass, and the temperature increment has an obvious effect on the thermal filtration and thermo‐osmosis process.

Justice, political ethics, and democracy. Assessing two levels of government

Fiat iustitia ne pereat mundus, literally ‘Justice must be done so the world may not perish’. It is a famous Latin proverb that forms the basis of modern jurisprudence. Both in the original version, ’Fiat iustitia e pereat mundus’, implying, ‘Let justice be done, and even the world may perish’ – and in our adjusted version, justice must be at the basis of human society, at least in a democratic political system. However, what kind of justice is most congruent with today’s pluralist democracy? The one is grounded on ethical intersubjective a priori mediation or directly applied justice regardless of its consequences. How can today’s democracy and comprehensive doctrines be compatible with negotiating pluralism and gaining stability within Albania successfully? To answer the above questions, in this article, we will use John Rawls’ response, introduced in his 1993 book Political Liberalism. Furthermore, another goal of this article is to elucidate the Albanian politician’s ethics outlook. In this regard, a set of fundamental questions arise here. For example, why do our politicians act as they do? Is there e proper political way to act? To cope with these questions, we will analyze Max Weber’s essay Between Two Laws to grasp the current Leader’s type of ethics. Weber’s classification of the ethic of conviction and ethic of responsibility, and to what extent he prescribes each ethic to the ‘ideal politician’, will be at the heart of this line of reasoning The article proceeds into four key sections — the first deals with assessing the Leader’s political ethics in current Albania. The second section provides a parsimonious classification of the current state of Albania’s democracy; the third section offers a short analysis of the Socialist Party government, both central and local, whereas the last part provides a solution for democratic consolidation through the empowerment of the Constitution.

An investigation on implementing a scenario on different cloud simulators

Recently, many algorithms have been introduced to provide solutions for Virtual Machine Consolidation in Cloud Data Center. Such Algorithms are usually implemented using many Cloud Simulators, which may have different representation and behavior of cloud infrastructure entities like Data Centers, Physical Machines(PMs), and Virtual Machines(VMs). In this paper, we investigated the impact of using a simulator on the implementation of Cloud infrastructure that is necessary for the Consolidation process, we chose Cloudsim and DISSECTCF simulators in particular since they both support Cloud infrastructure entities. Our aim is to find common entities for cloud simulators that are necessary to build the same infrastructure with particular interest on monitoring the CPU utilization and energy consumption. We report our experience with the implementation on the two Simulators, in addition to the limitation and differences we found during the reproducing process.

Theoretical Study on the Consolidation of Multiple Composite Foundations with Vertical Drains‐Impervious Piles considering Temperature Effect and Nonuniform Distribution of Initial Pore Pressure

For the problem of consolidation of multiple composite foundations of vertical drain‐impervious pile, considering the influence of temperature and nonuniform distribution of initial pore pressure, the consolidation control equations based on the assumption of equal strain are established, and the analytical solution method is adopted to give the analytical solution of consolidation of multiple composite foundations of the vertical drain‐impervious pile with trapezoidal, rectangular, positive triangular, and inverted triangular distribution of initial pore pressure. The correctness and reasonableness of the solutions are verified by comparing the degenerate solutions of this paper with the existing solutions. The consolidation properties of the multifaceted composite foundation are analyzed according to the solution of this paper. The results show that the initial pore pressure is faster to consolidate in a trapezoidal distribution than in a rectangular distribution, fastest to consolidate in an inverted triangular distribution and slowest to consolidate in a positive triangular distribution. The rate of consolidation of a multiple composite foundation can be significantly accelerated by increasing the temperature, the replacement rate of impervious piles, and the compression modulus. The rate of consolidation of a multiple composite foundation can be significantly increased compared to a single pile type foundation; the size of the permeability coefficient of the vertical drain almost represents the size of the drainage capacity of the composite foundation. The rate of consolidation of a multiple composite foundation is faster as the permeability coefficient of the vertical drain increases.

Analytical Solution for Consolidation of Vertical Drains‐Impervious Piles with Multiple Composite Foundations under Nonuniform Initial Pore Pressure and Time‐Dependent Well Resistance

For the vertical drains‐impervious pile multiple composite foundation consolidation problem, the effects of nonuniform distribution of initial pore pressure, variation of well resistance with time, and combined radial and vertical seepage in the soil are considered, and a consolidation control equation based on the assumption of equal strain is established based on the axisymmetric model. The analytical solution method is used to give an analytical solution for the consolidation of multiple composite foundations with vertical drains‐impervious piles with trapezoidal, rectangular, positive triangle, and inverted triangular distribution of initial pore pressure. The reasonableness of the solution of this study is verified by degradation analysis. According to the solution of the study, the consolidation properties of the multicomposite foundation were analyzed. The results show that the initial pore pressure is faster to consolidate with trapezoidal distribution than with rectangular distribution, the slowest to consolidate with positive triangular distribution, and the fastest to consolidate with inverted triangular distribution, and the larger the initial pore pressure value at the base of the soil layer, the slower the consolidation; the consolidation rate of the foundation all decreases with the increase of the well resistance factor, and the change of the well resistance mainly has an important influence on the later consolidation of the foundation; the vertical permeability coefficient of the soil has a greater influence on the consolidation of the foundation at the initial stage when the foundation thickness is small, and the vertical permeability coefficient of the soil has greater influence on the consolidation of the foundation at the later stage when the foundation thickness is large; the consolidation rate of foundation increases with the increase of replacement rate of impervious pile, compression modulus, and vertical permeability coefficient of soil. Compared with the single pile foundation, the multicomposite foundation can significantly improve the consolidation rate of foundation.

A semi-analytical solution for consolidation of ground with local permeable pipe pile

Aiming at optimization of drainage holes for permeable pile, a scheme of local pervious segment is introduced in the body of pipe pile to accelerate the dissipation of excess pore water pressure caused by pile driving. An axisymmetric consolidation model is established for a single local permeable pile in saturated clay. The semi-analytical solution is obtained using the boundary transform and integral transform methods. The effectiveness of the proposed solution is assessed by comparing with the results of degradation analysis, finite difference analysis and model test. Upon the successful calibration of the solution, the impacts of pervious segment parameters, geometric dimensions of pipe pile and soil physical parameters on the consolidation of soils around the pile are analyzed. Results show that local permeable pile can accelerate the soil consolidation based on the premise of structural strength of the pile body, and the acceleration effect is mainly in the early stage of consolidation. With the increase of pervious segment length and position, aspect ratio of pile, and soil permeability coefficient ratio, the benefit of local permeable pile is more apparent, which can provide reference for design.

Time‐varying characteristics of irregular rigid foundations on fractional visco‐poroelastic stratified cross‐anisotropic soils

AbstractBased on the consolidation solutions of cross‐anisotropic stratified fractional visco‐poroelastic soils, the interaction between an irregular rigid foundation and the underlying soils in the time domain is studied. Firstly, the foundation is discretized into a series of elements, which is similar to the division principle of the finite element method (FEM). The displacement equations of the foundation elements are established according to the fact that the rigid foundation remains flat when loaded. Secondly, the flexibility matrix of the soils is obtained from the consolidation solution, which is taken as the kernel function of the Boundary element method (BEM). After that, the interaction equation is derived according to the displacement compatibility condition and equilibrium of forces between the rigid foundation and the soils. So, the relation between the displacement and the contact force of the soils is attained. Finally, the rotation, displacement, and reaction of the foundation are obtained by solving the interaction equation. The results are compared with several published references to prove the validity of this study. Furthermore, numerical examples are designed to investigate the effects of the viscoelasticity, cross‐anisotropy, stratification, aspect ratio and the irregular shape on the time‐varying interaction.

A Short Note on the Degradation and Consolidation of Masonry Structures

Abstract This paper discusses the factors that can lead to the degradation of masonry structures and provides an overview of the existing techniques for their rehabilitation and consolidation. The degradation of masonry is often related to negative actions of the environment, such as water penetration, freeze-thaw cycles, chemical attacks, and exposure to pollutants. These factors can lead to the appearance of cracks, scaling, erosion, and other types of deterioration of masonry. To preserve masonry structures, frequent monitoring and repairs (locally), preferably immediately after any degradation, are the most important measures. When degradation occurs, prompt action is necessary to prevent further deterioration and to apply appropriate rehabilitation and consolidation methods. Rehabilitating a construction involves replacing or restoring degraded elements to restore functionality to the pre-degradation level and to improve the overall performance of the structure. In contrast, consolidation focuses on strengthening an existing structure by adding new structural elements or by applying specific consolidation techniques with the aim of achieving increased structural capacity. These processes are often interconnected and part of a larger process of restoring or maintaining buildings or structures. Regarding traditional solutions for consolidating masonry elements and structures, these consist of repairing or rebuilding affected areas with classic materials, such as simple or reinforced mortars, welded meshes, dowels, steel bars and profiles. Traditional masonry repair works include filling cracks by injection, partial disassembly of walls followed by reconstruction, dismantling of mortar joints followed by deep filling, stitching of cracks with steel dowels, and reinforcing and facing with mesh or mortar. These techniques are applied according to the degree and type of degradation of the existing structure, as well as local and environmental conditions, with the aim of ensuring efficient and durable consolidation of the structure. The informed decision on the rehabilitation or consolidation solution used and how it is to be applied is usually made after extensive studies and consultations to achieve the best possible result. Generally, masonry structures are considered very resistant and durable, due to their history of over 6000 years. However, proper care and attention to detail are crucial to prevent degradation and to maintain masonry structures in good condition.

Prediction of Radial Consolidation Settlement with Consideration of Sampling Range Effect: Updated Observational Methods

AbstractThis study investigated the disadvantages of existing observational methods using theoretical (radial consolidation solution) and actual (radial consolidation test with 24-h duration) settl...

Insight into the influence of pH on the precipitation induced by bacteria

AbstractIn recent years, microbial mineralization has aroused great attention in soil remediation. The pH is one of the critical factors that control the microbial mineralization process. However, the interaction mechanism between the environment pH and the mineralization process has not been clarified yet. This paper focused on the growth of bacteria, urease activity and the calcium utilization rate. Besides, we detected the particle size distribution, morphological characteristics and the composition of precipitations formed at different pH. Moreover, we evaluated the triaxial compressive strength of sand columns processed by different pH consolidation solutions. Additionally, the volume fraction of precipitations and its spatial distribution in sand columns were analysed by X‐ray CT. The results demonstrated that pH significantly influences the growth of bacteria and urease activity, especially in the bacteria's early growth stage. This paper also indicates that the environmental pH impacts the volume fraction of precipitations, affecting the consolidation properties. We also found a negative correlation between the cohesion and the total volume fraction of precipitations. In contrast, there was a positive correlation between the friction angle and the total volume fraction of precipitations. Moreover, we observed that the precipitations mainly distributed in the pores and throats, increasing the sand particles’ roughness. Furthermore, we proposed four cementing models for the spatial relationship between the precipitations and the sand particles, which provides new insight into the consolidation mechanism. This paper guides us to promote this environmentally friendly technology to treat soil liquefaction and desertification.

Analytical Solution for One-Dimensional Nonlinear Consolidation of Saturated Double-Layered Soil Subjected to Cyclic Loadings

Cyclic loading-induced consolidation behavior of soft soil is of great interest for the analysis of offshore and onshore structures. In this study, an analytical solution for one-dimensional (1D) nonlinear consolidation of saturated double-layered soil under various types of cyclic loadings such as trapezoidal cyclic loading, rectangular cyclic loading, and triangular cyclic loading was derived. The proposed solution was subsequently degenerated into solutions for special cases and compared to the existing solutions. The degenerate solutions show good agreement with the existing results, which proves that the proposed solutions are more general ones for 1D nonlinear consolidation of saturated soils under time-dependent loading. Finally, a comprehensive parametric study was conducted to investigate the influences of different layer parameters, drainage conditions, and loading parameters on nonlinear consolidation of saturated double-layered soil under cyclic loadings.

Cost Allocation for Less-Than-Truckload Collaboration via Shipper Consortium

We study the problem of collaborative less-than-truckload (LTL) transportation in the form of a shipper consortium, which is operated by a third-party logistics provider (3PL) through a cross-dock/pooling network. The 3PL has responsibility for planning the combined loads prior to actual shipments, hiring and routing carriers to execute shipping, and allocating the cost to the shippers in the consortium. Shippers receive substantial cost savings from combined truckload shipments. However, achieving consolidation and realizing this benefit requires addressing two essential issues: (i) how to find an approximately optimal consolidation solution in a large network with many freights and (ii) how to determine a fair cost allocation rule among the shippers’ consolidated freights that ensures budget balance while minimally violating coalitional stability. Our work resolves these two issues. We formulate a time-space network flow model of the problem under both incremental and all-unit discount structures of LTL rates and propose a computationally efficient algorithm based on local search heuristics. We model the problem of allocating cost to the shippers as a cooperative game. We decompose and linearize the Lagrangian dual problem by using total unimodularity and concavity. We propose an efficiently computable cost allocation rule from the linearized dual models. The dual rule ensures stable cooperation but may have underallocation equal to a duality gap. To cover the underallocation, we further develop a budget covering procedure and define an [Formula: see text]-core allocation with desirable properties. Through extensive computational experiments, we find that the shipper consortium reduces total shipping costs by more than 40% in most cases; meanwhile, the [Formula: see text]-core allocation is typically in the core for small-scale networks while violating stability by at most 5% for large-scale networks and provides consolidated freights with more than 50% individual cost savings on average.

One-dimensional consolidation of multilayered aquifer systems with viscoelastic properties induced by time-dependent groundwater drawdown

Most analytical and semi-analytical models for pumping-induced land subsidence invoke the simplifying assumptions regarding characteristics of geomaterials, as well as the pattern of drawdown response to pumping. This paper presents an analytical solution for one-dimensional consolidation of the multilayered soil due to groundwater drawdown, in which viscoelastic property and time-dependent drawdown are taken into account. The presented solution is developed by using the boundary transformation techniques. The validity of the proposed solution is verified by comparing with a degenerated case for a single layer, as well as with the numerical solutions and experimental results for a two-layer system. The difference between the average consolidation degree U p , defined by hydraulic head, and U s , defined by total settlement, is discussed. Detailed parametric studies are conducted to reveal the effects of viscoelastic properties and drawdown patterns on the consolidation process. It is revealed that while the effect of different drawdown response patterns is significant during the early–intermediate stages of consolidation, the viscoelastic properties may have a more dominant influence on long-term consolidation behaviour, depending on the values of the material parameters, which are reflected in both the deformation process of soil layers and the dissipation of excess pore-water pressure.

Radial consolidation considering non-linear compressibility and permeability of structured soils

Practitioners commonly use analytical solutions to predict radial consolidation behavior around vertical drains. Soil under consolidation exhibits non-linear characteristics in compressibility and permeability that varies with a change of effective stress. In particular, the presence of soil structure in natural clay plays an important role in the non-linear characteristics. This study presents a new semi-analytical solution for radial consolidation in structured soil, which can be easily incorporated into conventional spreadsheets. The proposed solution is validated by comparison with finite element prediction and field measurements from a case history of an embankment. A parametric study performed on soil structure indicates that soil structure would slow down the dissipation of excess pore water pressure and increase vertical strain. The design implications of these effects are discussed.

Analytical Solutions for the Radial Consolidation of Unsaturated Foundation with Prefabricated Vertical Drain Based on Fourier Series Expansion Theory

This paper presents the analytical solution of the radial consolidation of a prefabricated vertical drain (PVD) foundation under the unsaturated condition. In the proposed modeling, air and water phases in the foundation are thought to dissipate horizontally toward to the drain, and the smear effect, drain resistance and external time-dependent loading are fully considered. The analytical mathematical tools, namely the general integration method, Fourier series expansion method, decoupling method and the constant variation method, are utilized to solve the partial differential equations. Moreover, the current solutions are verified with existing solutions in the literature. Finally, a case study considering the ramp loading and exponential loading is conducted to investigate the consolidation patterns under various loading parameters. The results show that smear effect and drain resistance can significantly hinder the dissipation process of excess pore pressures, and different external loading types will lead to various dissipation characteristics (i.e., peak values).

Semi-analytical solution for the one-dimensional consolidation of multi-layered unsaturated soils with semi-permeable boundary

Semi-analytical solution for the one-dimensional consolidation of multi-layered unsaturated soils with semi-permeable boundary

A closed-form solution for 2D plane strain consolidation in unsaturated soils considering the lateral semipermeable drainage boundary

This paper presents a closed-form solution for two-dimensional (2D) plane strain consolidation in unsaturated soils with the lateral semipermeable drainage boundary. The partial differential governing equations (PDEs) of the 2D plane strain consolidation were expanded into two ordinary differential equations (ODEs) about time t by the eigenfunctions determined from the lateral semipermeable drainage boundary conditions. Subsequently, the ODEs were solved by the Laplace transform and its inverse transform analytically. The closed-form solution is then verified against the finite element simulation and the existing semi-analytical. The results show that the normalized pore-water pressure and pore-air pressure calculated by the closed-form solution are in perfect agreement with both finite element simulations and the existing semi-analytical solution, which indicates the correctness of the analytical solution. Based on the presented closed-form solution, it can be concluded that the closed-form solution is found to be more straightforward, simpler, and computationally faster than the semi-analytical solution. Moreover, only when the soil size H/L is greater than 1, it is meaningful to discuss the effect of semipermeable boundary on the consolidation behavior.