One-dimensional consolidation with uncertain properties

1992 ◽  
Vol 29 (1) ◽  
pp. 161-165 ◽  
Author(s):  
Han Ping Hong
Keyword(s):  
Pore Pressure ◽  
Probability Distributions ◽  
Random Variable ◽  
Excess Pore Pressure ◽  
Coefficient Of Consolidation ◽  
One Dimensional ◽  
Degree Of Consolidation ◽  
Fifth Order ◽  
Matching Probability ◽  
Excess Pore

Different reasonable probability distributions can be assigned for the coefficient of consolidation, C. But if no more than the first few probability moments of the excess pore pressure and of the degree of consolidation which are functions of C are of concern, it is advantageous to use a simpler, distribution-free method for matching probability moments of C. In this note, the method of discretization of probability is used to analyze one-dimensional consolidation. The solutions, influenced by the probability moments of third, fourth, and fifth order of C, are presented. Key words : probability, discretization, coefficient of consolidation, excess pore pressure, degree of consolidation, moments, random variable.

scholarly journals One-Dimensional Consolidation of Double-Layered Foundation with Depth-Dependent Initial Excess Pore Pressure and Additional Stress

2015 ◽  
Vol 2015 ◽  
pp. 1-13 ◽  
Author(s):  
Junhui Zhang ◽  
Guangming Cen ◽  
Weizheng Liu ◽  
Houxuan Wu
Keyword(s):  
Pore Pressure ◽  
Excess Pore Pressure ◽  
Additional Stress ◽  
Upper Crust ◽  
Consolidation Process ◽  
One Dimensional ◽  
Soft Foundation ◽  
Special Cases ◽  
Loading Modes ◽  
Excess Pore

A model for one-dimensional consolidation of a double-layered foundation considering the depth-dependent initial excess pore pressure and additional stress and time-dependent loading under different drainage conditions was presented in this study and its general analytical solution was deduced. The consolidation solutions of several special cases of single-drained and double-drained conditions under an instantaneous loading and a single-level uniform loading were derived. Then, the average degree of consolidation of the double-layered foundation defined by settlement was gained and verified. Finally, the effects of the initial excess pore pressure distributions, depth-dependent additional stress, and loading modes on the consolidation of the soft foundation with an upper crust with different drainage conditions were revealed. The results show that the distributions of initial excess pore pressure and additional stress with depth and loading rates have a significant influence on the consolidation process of the soft foundation with an upper crust. This influence is larger with the single-drained condition than that with the double-drained condition. Comparing the consolidation rate with a uniform initial pore pressure and additional stress, their decreasing distribution with depth quickens the consolidation at the former and middle stages. Moreover, the larger the loading rate is, the quicker the consolidation of the soft foundation with an upper crust is.

Analytical Solution and Consolidation Analysis of One-dimensional Large Strain Consolidation Differential Equation

2020 ◽  
Vol 15 ◽  
Author(s):  
Shijia Liu ◽  
Huifeng Su ◽  
Tao Yu ◽  
Shuo Zhao ◽  
Zhicheng Cui
Keyword(s):  
Analytical Solution ◽  
Pore Pressure ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Control Variable ◽  
Excess Pore Pressure ◽  
Excess Pore Water Pressure ◽  
One Dimensional ◽  
Small Strains ◽  
Excess Pore

Abstract:: According to the universal one-dimensional consolidation equation introduced by Gibson, the governing equation with the excess pore water pressure as the control variable is derived, and the Fourier series solution under the boundary condition of single-sided drainage is deduced in detail by the standard mathematical physical method. It verifies the correspondence between the analytical solution and the numerical solution from a theoretical point of view. Using this analytical solution, the nonlinear distribution of the excess pore pressure along the depth direction is obtained, and the traditional small strain consolidation is compared in terms of the average consolidation degree and the final settlement. Soft soil foundation, large deformation foundation Derive a consolidation equation for soft soils with large deformations using the super-static pore pressure as the control variable Formula derivation, Example analysis Based on Gibson's general equation of consolidation and its theory, the detailed derivation process of differential equations with excess pore water pressure as the control variable is given. According to the example, the image shows the distribution of excess pore pressure with depth, and comparative analysis of large and small strains, If all other conditions are the same, When mv1=1 MPa-1, it can be calculated according to the large and small strains, but when mv1≥3MPa-1, the two errors are large, The calculation must be considered separately.

Consolidation of a soil layer subsequent to cessation of deposition

2005 ◽  
Vol 42 (2) ◽  
pp. 678-682
Author(s):  
Guofu Zhu ◽  
Jian-Hua Yin
Keyword(s):  
Pore Pressure ◽  
Soil Layer ◽  
Average Degree ◽  
Excess Pore Pressure ◽  
Triangular Distribution ◽  
Pressure Distributions ◽  
Pore Pressures ◽  
Degree Of Consolidation ◽  
Excess Pore Pressures ◽  
Excess Pore

It is necessary in certain cases to estimate the progress of consolidation in a soil layer that has ceased increasing in thickness over time. In this paper, the existing excess pore pressures for two time–thickness relations are used as the "initial" pore pressures for analysing the consolidation of soil subsequent to the cessation of deposition. Average degrees of consolidation of the soil layer are presented for one-way drainage and two-way drainage boundary conditions. The average degrees of consolidation are compared with those for uniform and triangular initial excess pore pressure distributions. It is found that the average degree of consolidation for one-way drainage boundaries can be estimated using the value for the triangular distribution. The average degree of consolidation for two-way drainage boundaries is bound by the averages for both the uniform and the triangular initial excess pore pressure distributions.Key words: consolidation, deposition, drainage, settlement, soil.

scholarly journals Numerical Analysis of Staged Construction of an Embankment on Soft Soil

2021 ◽  
Author(s):  
Ayesha Binta Ali ◽  
Mehedi Ahmed Ansary
Keyword(s):  
Finite Element ◽  
Numerical Analysis ◽  
Pore Pressure ◽  
Soft Soil ◽  
Excess Pore Pressure ◽  
Element Analysis ◽  
Staged Construction ◽  
Modeling Software ◽  
Degree Of Consolidation ◽  
Excess Pore

Abstract The objective of this study was to predict the excess pore pressure and settlement of an embankment over soft ground, treated with vertical drain, through numerical analysis of staged construction. To carry out finite element analysis, numerical modeling software PLAXIS 3D was used. The practical demonstration was demonstrated by validating two case studies; the first one was a trial embankment at the Krishnapatnam Ultra Mega Power Project in Nellore, Andhra Pradesh, India and the second one was the Second Bangkok International Airport or Suvarnabhumi Airport, about 30 km from the city of Bangkok, Thailand. After the successful validation of the program, detailed finite element modelling of an embankment resting on soft soil was conducted. Moreover, the degree of consolidation and factor of safety were also determined. There was rapid dissipation of excess pore pressure and maximum settlement at the mid-height of the embankment. In contrast, the dissipation of excess pore pressure was very slow just below the embankment and it increased with the increment of the depth of the clay layer. Moreover, with the rise of the distance from the centre of the embankment, the dissipation of the excess pore pressure also raised and took less time, the settlement also increased.

Study on Soil Consolidation Coefficient on CPTU Model Test

2011 ◽  
Vol 201-203 ◽  
pp. 2587-2592
Author(s):  
Yan Chun Tang ◽  
Gao Tou Meng ◽  
Qiu Feng Mao
Keyword(s):  
Pore Pressure ◽  
Model Test ◽  
Vertical Direction ◽  
Test Methods ◽  
Excess Pore Pressure ◽  
Soil Consolidation ◽  
Consolidation Test ◽  
Consolidation Coefficient ◽  
Degree Of Consolidation ◽  
Excess Pore

Through analyzing excess pore pressure dissipation datum measured by CPTU probe and pore pressure mini-transducers on CPTU model test, the consolidation coefficient of soil of CPTU model test has been computed. Based on axis-symmetric consolidation model and Terzaghi consolidation theory, the computing equation of soil horizontal consolidation coefficient on CPTU model test has been acquired; on CPTU model test 50% degree of consolidation has been applied as calculate standard to compute soil horizontal consolidation coefficient, and dissipating time of 50% degree of consolidation can be acquired by normalized excess pore pressure dissipation curves based on excess pore pressure dissipation datum; through a series of indoor consolidation tests, the consolidation coefficient of remolded soil of CPTU model test sampling by horizontal and vertical direction has been acquired, and the results show that vertical consolidation coefficient is about 1.6 times greater than horizontal consolidation coefficient on indoor consolidation test, and large difference between horizontal and vertical property of remolded clay soil on CPTU model test has been existed; compared with the value of two test methods, the value of horizontal consolidation coefficient acquired by CPTU model test is roughly 100 times greater than the value of horizontal consolidation coefficient acquired by indoor consolidation test. The achieved result can provide a foundation for further study for CPTU mechanism.

Effect of unloading duration on unconfined compressive strength

1999 ◽  
Vol 36 (1) ◽  
pp. 166-172 ◽  
Author(s):  
M A Fam ◽  
M B Dusseault
Keyword(s):  
Compressive Strength ◽  
Pore Pressure ◽  
Unconfined Compressive Strength ◽  
Excess Pore Pressure ◽  
Triaxial Tests ◽  
Compression Tests ◽  
Unconfined Compression ◽  
Coefficient Of Consolidation ◽  
Unconfined Compression Test ◽  
Excess Pore

This note examines the effect of unloading duration on unconfined compression test results. Artificial clayey specimens were prepared using the slurry consolidation technique. Extracted specimens were loaded vertically under K0 conditions, and the load was kept constant until the end of primary consolidation. Specimens were unloaded and unconfined compression tests were carried out at different times after unloading. It is observed that the longer the unloading duration, the lower the measured unconfined strength. This behavior is attributed to the presence of negative excess pore pressure that dissipates with time, reducing the strength. Using the measured coefficient of consolidation, the degree of excess pore pressure dissipation and therefore the average mean effective stress near the failure zone can be calculated at the time of failure. Mohr circles are drawn tangential to the total shear envelope, using the calculated mean effective stresses. Reasonable agreement between predicted and measured unconfined compressive strengths has been observed, suggesting that consolidation theory can be adopted to assess the effect of unloading duration on unconfined compressive strength. Finally, engineering applications using a similar concept are briefly discussed.Key words: clays, unloading, consolidation, unconfined compression tests, triaxial tests.

scholarly journals Study on One-Dimensional Large Deformation Consolidation of Soil considering Liquid Phase Inertia

2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Xin-Yu Xie ◽  
Chun-Tai Xu ◽  
Jin-Zhu Li ◽  
Zhong-Jin Wang ◽  
Wen-Jun Wang
Keyword(s):  
Liquid Phase ◽  
Large Deformation ◽  
Pore Pressure ◽  
Large Strain ◽  
Excess Pore Pressure ◽  
Inertia Effect ◽  
One Dimensional ◽  
Initial Stage ◽  
Phase Acceleration ◽  
Excess Pore

Classical consolidation theory ignores the influence of soil liquid phase acceleration. This paper considers the influence of liquid phase acceleration on the stress balance equation during the consolidation of soil, obtains the one-dimensional equation governing quasi-hydrostatic consolidation under large deformation with the consideration of the inertia of the liquid phase, and solves the governing equations by finite element method. The calculation results show that the liquid phase inertia effect of the soil will cause excess pore pressure in the soil, obviously increasing in the initial stage of consolidation, and the self-weight of soil exerts an influence on the excess pore pressure at the later stages of consolidation. The liquid phase inertia effect parameter Dc determines the strength of the liquid phase inertia effect. A larger Dc value results in a larger increase in the excess pore pressure, and the later the liquid phase inertial effect occurs, the longer the duration is. In the large strain consolidation analysis, especially at the initial stage of consolidation, it is necessary to consider the liquid phase inertia effect of the soil.

Vibro-Stone Column Reinforcement Mechanism and Numerical Analysis

2012 ◽  
Vol 446-449 ◽  
pp. 1940-1943
Author(s):  
Yang Liu ◽  
Hong Xiang Yan
Keyword(s):  
Numerical Simulation ◽  
Numerical Analysis ◽  
Pore Pressure ◽  
Numerical Procedure ◽  
Numerical Results ◽  
Excess Pore Pressure ◽  
Stone Column ◽  
Reinforcement Mechanism ◽  
Consolidation Theory ◽  
Excess Pore

Numerical simulation of vibro-stone column is taken to simulate the installation of vibro-stone column. A relationship based on test is adopted to calculate the excess pore pressure induced by vibratory energy during the installation of vibro-stone column. A numerical procedure is developed based on the formula and Terzaghi-Renduric consolidation theory. Finally numerical results of composite stone column are compared single stone column.

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