scholarly journals Modified Maag’s Spherical Diffusion Model of Vacuum Penetration Grouting

2018 ◽  
Vol 2018 ◽  
pp. 1-7 ◽  
Author(s):  
Feng Huang ◽  
Jianguo Lyu ◽  
He Gao ◽  
Guihe Wang
Keyword(s):  
Diffusion Model ◽  
Diffusion Theory ◽  
Scientific Basis ◽  
Theory Model ◽  
Distribution Law ◽  
Modified Model ◽  
Grouting Pressure ◽  
Proposed Model ◽  
Penetration Grouting ◽  
Spherical Diffusion

The penetration grouting is very widely used in geotechnical engineering nowadays, but the slurry diffusion radius is not long enough because of low grouting pressure. The vacuum grouting method is proposed to solve this problem. However, there is no diffusion theory model of vacuum grouting, which makes the practical application lack scientific basis. In this paper, the distribution law of vacuum negative pressure in soil is deduced. Then, the boundary conditions of Maag’s spherical diffusion model are modified by the vacuum pressure distribution law. After that, the vacuum modification model is deduced. Finally, Maag’s model and modified model are analyzed according to a published experiment, which proves that the vacuum modification model is suitable for predicting the slurry diffusion of vacuum grouting. The proposed model provides a reference for the theoretical study of vacuum grouting.

Study on the generalized k-Hilfer–Prabhakar fractional viscoelastic–plastic model

2021 ◽  
pp. 108128652110258
Author(s):  
Yi-Ying Feng ◽  
Xiao-Jun Yang ◽  
Jian-Gen Liu ◽  
Zhan-Qing Chen
Keyword(s):  
Constitutive Model ◽  
Three Dimensional ◽  
Sensitivity Analyses ◽  
Creep Process ◽  
Fractional Operator ◽  
Modified Model ◽  
Proposed Model ◽  
Accelerated Creep ◽  
The Laplace Transform ◽  
Classical Models

The general fractional operator shows its great predominance in the construction of constitutive model owing to its agility in choosing the embedded parameters. A generalized fractional viscoelastic–plastic constitutive model with the sense of the k-Hilfer–Prabhakar ( k-H-P) fractional operator, which has the character recovering the known classical models from the proposed model, is established in this article. In order to describe the damage in the creep process, a time-varying elastic element [Formula: see text] is used in the proposed model with better representation of accelerated creep stage. According to the theory of the kinematics of deformation and the Laplace transform, the creep constitutive equation and the strain of the modified model are established and obtained. The validity and rationality of the proposed model are identified by fitting with the experimental data. Finally, the influences of the fractional derivative order [Formula: see text] and parameter k on the creep process are investigated through the sensitivity analyses with two- and three-dimensional plots.

CC-CV charge protocol based on spherical diffusion model

2011 ◽  
Vol 18 (2) ◽  
pp. 319-322 ◽  
Author(s):  
Lian-xing Li ◽  
Xin-cun Tang ◽  
Yi Qu ◽  
Hong-tao Liu
Keyword(s):  
Diffusion Model ◽  
Spherical Diffusion

Study on Model of Back-Filled Grouting of Shield Tunnel

2014 ◽  
Vol 919-921 ◽  
pp. 883-886
Author(s):  
Dao Yuan Wang ◽  
Dong Li ◽  
Jin Xiu Yuan
Keyword(s):  
Time Pressure ◽  
Time Dependent ◽  
Shield Tunnel ◽  
Distribution Law ◽  
Spreading Model ◽  
Grouting Pressure ◽  
Dependent Behavior ◽  
Cylindrical Diffusion

Basing on the theory of maag cylindrical diffusion, back grout diffusion radius and grouting pressure formula of shield tunnel were derived in two cases of the viscosity time-dependent behavior or not.The distribution law of diffusion radius and the pressure to segments were obtained by applicating the spreading model in some project.The results show that grout diffusion radius and grouting pressure both increase with the increasing of grouting time and grouting pressure whether considering the viscosity time-dependent behavior or not.In the same grouting time (pressure),the calculated values that unconsidering the viscosity time-dependent behavior are bigger than the values of considering.

Spherical Diffusion Model of Interspecies Hydrogen Transfer in Steady-State Methanogenic Reactors

1992 ◽  
Vol 26 (9-11) ◽  
pp. 2389-2392 ◽  
Author(s):  
D. P. Smith
Keyword(s):  
Mathematical Model ◽  
Steady State ◽  
Diffusion Model ◽  
Hydrogen Concentration ◽  
Hydrogen Transfer ◽  
Solution Concentration ◽  
Bulk Solution ◽  
Transfer Resistance ◽  
Concentration Difference ◽  
Spherical Diffusion

A previously developed spherical diffusion model of interspecies molecular hydrogen transfer was applied to a mathematical model of ethanol and propionate methanogenesis in a dispersed-growth, continuously stirred tank reactor (CSTR). Steady-state methanogenesis at a 0.10 day−1 space velocity required a hydrogen concentration difference of 1.12 × 10−5 aim (8.4 × 10−12 moles/cm3) between the surface of the propionate organisms and the bulk solution. The total difference in hydrogen concentration between source organism and sink organism Ihydrogenotrophic methanogenstwas 2.1 × 10−5 atm (1.6 × 10−11 moles/cm3). Steep gradients in hydrogen concentration existed only at close proximity to the bacterial spheres, with hydrogen concentration approaching bulk solution concentration at distances greater than 10 microns. Small hydrogen gradients and the bulk solution concentration prevailed through the majority of the reactor aqueous volume. Overall, the incorporation of hydrogen mass transfer resistance into the mathematical model had only a slight effect on hydrogen partial pressure, organic substrate levels, and bacterial mass concentrations predicted by the steady-state solution.

Three-Group Albedo Method Applied to the Diffusion Phenomenon with Up-Scattering of Neutrons

2006 ◽  
Vol 258-260 ◽  
pp. 403-408
Author(s):  
André Miguel Barge Pontes Torres Terra ◽  
Jorge Alberto Valle da Silva ◽  
Ronaldo Glicério Cabral
Keyword(s):  
Radiation Transport ◽  
Diffusion Theory ◽  
Theory Model ◽  
Model Case ◽  
Diffusion Phenomenon ◽  
Conventional Radiation ◽  
Major Application ◽  
Albedo Method ◽  
Transport Method

The main objective of this research is to develop a three-group neutron Albedo algorithm considering the up-scattering of neutrons in order to analyze the diffusion phenomenon in nonmultiplying media. The neutron Albedo method is an analytical method that does not try to solve explicit describing equations for the neutron fluxes [1,2]. Thus the neutron Albedo methodology is very different from the conventional methodology, as the neutron diffusion theory model. Graphite is analyzed as a model case. One major application is in the determination of the nonleakage probabilities with more understandable results in physical terms than conventional radiation transport method calculations.

Study on Grout Permeation Model of an Equipment for Grouting in Roller Compacted Concrete

2011 ◽  
Vol 287-290 ◽  
pp. 2840-2843 ◽  
Author(s):  
Wei Ping Peng ◽  
Xiong Zhao ◽  
Zhao Liu
Keyword(s):  
Permeability Coefficient ◽  
Diffusion Theory ◽  
Power Station ◽  
Construction Time ◽  
Hydraulic Power ◽  
Roller Compacted Concrete ◽  
Rcc Dam ◽  
Grouting Pressure ◽  
Cylindrical Diffusion ◽  
The Relationship

Based on cylindrical diffusion theory and characteristics of enriched vibrated Roller Compacted Concrete (RCC), a model of grout permeation was established. According to this model and generalized Darcy’s law, a formula was deduced, which shows the relationship among diffusion radius of grout, grouting pressure, radius of grouting pipe, construction time, viscosity of grout, permeability coefficient of RCC, porosity of RCC and rheological index of grout, computing steps by this formula were presented, and results of computing grout diffusion radius for an equipment of grouting in Roller Compacted Concrete was given, which was developed for construction of RCC dam at Tingzikou hydraulic power station.

FSM Based Collaborative Design Oriented Component Agent Model

2014 ◽  
Vol 988 ◽  
pp. 437-440
Author(s):  
Cai Mao Su ◽  
Zhong Li
Keyword(s):  
Data Model ◽  
Collaborative Design ◽  
Theory Model ◽  
Time To Market ◽  
Agent Based ◽  
Agent Model ◽  
Advanced Technologies ◽  
Proposed Model ◽  
Collaborative Product Design ◽  
Finite State

The keen competitive market is forcing companies to adopt various advanced technologies, such as collaborative design, to short the product development time-to-market. In this paper, the theory model of the component agent based on finite state machine is proposed first. Secondly, a product component agent frame is proposed by combining the proposed agent model with collaborative design-oriented product data model. Finally, an application is given which shows that the proposed model can enhance the ability of the collaborative product design.

A Modified Model for Friction Reduction by Vibrating Drill-String Longitudinally

2014 ◽  
Vol 535 ◽  
pp. 597-601 ◽  
Author(s):  
Peng Wang ◽  
Hong Jian Ni ◽  
Zhi Na Li ◽  
Rui He Wang
Keyword(s):  
Drill String ◽  
Friction Reduction ◽  
Contact Theory ◽  
Rock Surface ◽  
Modified Model ◽  
String Vibration ◽  
Tangential Stiffness ◽  
Proposed Model ◽  
Drilling Method ◽  
Coulomb Model

Drill-string vibration excitation longitudinally is a potential drilling method for reducing friction between drill-string and borehole rock. This article assumes that borehole rock surface is composed of elliptical asperities, based on elastic-plastic contact theory, a modified model for friction reduction by vibrating drill-string longitudinally is developed. The results show that the tangential stiffness of borehole rock surface decreased with increasing ovality of asperity. Further, at the same ovality, thin and tall asperity has bigger tangential stiffness than short and fat asperity. Only when the tangential stiffness of borehole rock is greater than a certain threshold, the friction force calculated by proposed model in this paper can appear reverse phenomenon. When the tangential stiffness tends to infinity, the result tends to Coulomb model. The conclusions provide basis for research and application of drill-string vibration longitudinally friction reduction technology.

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