The theory of one-dimensional consolidation of saturated clays. II. Finite nonlinear consolidation of thick homogeneous layers

1981 ◽  
Vol 18 (2) ◽  
pp. 280-293 ◽  
Author(s):  
Robert E. Gibson ◽  
Robert L. Schiffman ◽  
Kenneth W. Cargill
Keyword(s):  
Pore Water Pressure ◽  
Water Pressure ◽  
Excess Pore Pressure ◽  
Conventional Theory ◽  
One Dimensional ◽  
Consolidation Settlement ◽  
Finite Strain Theory ◽  
Effective Stress Analysis ◽  
The One ◽  
Excess Pore

The one-dimensional consolidation of a thick clay layer, initially consolidated fully under its own weight, is considered. Account is taken of the variation of the coefficients of permeability and compressibility as consolidation proceeds. To render the theory consistent finite strains are permitted. Comparisons with conventional theory, in a practical example, show that nonlinear finite strain theory predicts the progress of consolidation settlement to be substantially swifter than indicated by conventional theory, although the dissipation of excess pore pressure may be slower. The consequences of this indicate that conventional consolidation theory has the potential to seriously underestimate the excess pore water pressure in a soft layer. As a result, the estimated shear strength would, if an effective stress analysis were used, be overestimated; a potentially unsafe design could emerge.

Vacuum and surcharge combined one-dimensional consolidation of clay soils

2002 ◽  
Vol 39 (5) ◽  
pp. 1126-1138 ◽  
Author(s):  
E Mohamedelhassan ◽  
J Q Shang
Keyword(s):  
Pore Water ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Clay Soils ◽  
Soil Consolidation ◽  
Excess Pore Water Pressure ◽  
One Dimensional ◽  
Consolidation Model ◽  
The One ◽  
Excess Pore

In this study, a vacuum and surcharge combined one-dimensional consolidation model is developed. Terzaghi's consolidation theory is revisited by applying the initial and boundary conditions corresponding to combined vacuum and surcharge loading on a soil. A test apparatus is designed, manufactured, and assembled to verify the model. The apparatus has the capacity of applying designated vacuum and surcharge pressures to a soil specimen, and it allows for the measurement of the excess pore-water pressure, settlement, and volume change during the consolidation process. Two series of tests are performed using the apparatus on two reconstituted natural clay soils, namely, the Welland sediment at water contents close to its liquid limit and the Orleans clay, reconstituted and consolidated under an effective stress of 60 kPa. The former test series mimics the strengthening of a very soft soil, such as the hydraulic fill used in land reclamation. The latter test series is designed to study vacuum–surcharge combined strengthening of a consolidated soil. It is demonstrated from the experiments that the one-dimensional vacuum-surcharge consolidation model describes the consolidation behaviour of both soils well. The consolidation characteristics of the soils show no discrimination against the nature of the consolidation pressure, namely, whether they are consolidated under the vacuum pressure alone, under the surcharge pressure alone, or under a pressure generated by the combined application of vacuum and surcharge. The study concluded that the soil consolidation characteristics obtained from the conventional consolidation tests can be used in the design of vacuum preloading systems, provided that the one-dimensional loading condition prevails.Key words: consolidation, soil improvement, vacuum pressure, surcharge pressure, excess pore-water pressure, soil consolidation parameters.

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.

scholarly journals Analytical Solution for One-Dimensional Consolidation of Soil with Exponentially Time-Growing Drainage Boundary under a Ramp Load

2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
Ming Sun ◽  
Meng-fan Zong ◽  
Shao-jun Ma ◽  
Wen-bing Wu ◽  
Rong-zhu Liang
Keyword(s):  
Analytical Solution ◽  
Pore Water ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Excess Pore Water Pressure ◽  
One Dimensional ◽  
The One ◽  
Interface Parameters ◽  
Ramp Load ◽  
Excess Pore

By introducing the exponentially time-growing drainage boundary, this paper investigated the one-dimensional consolidation problem of soil under a ramp load. Firstly, the one-dimensional consolidation equations of soil are established when there is a ramp load acting on the soil surface. Then, the analytical solution of excess pore water pressure and consolidation degree is derived by means of the method of separation of variables and the integral transform technique. The rationality of this solution is also verified by comparing it with other existing analytical solutions. Finally, the consolidation behavior of soil is studied in detail for different interface parameters or loading scheme. The results show that the exponentially time-growing drainage boundary can reflect the phenomenon that the excess pore water pressure at the drainage boundaries dissipates smoothly rather than abruptly from its initial value to the value of zero. By adjusting the values of interface parameters b and c, the presented solution can be degraded to Schiffman’s solution, which can compensate for the shortcoming that Terzaghi’s drainage boundary can only consider the two extreme cases of fully pervious and impervious boundaries. The significant advantage of the exponentially time-growing drainage boundary is that it can be applied to describe the asymmetric drainage characteristics of the top and bottom drainage surfaces of the actual soil layer by choosing the appropriate interface parameters b and c.

Finite Element Analysis for Subgrade Consolidation Settlement in Soft Soil

2013 ◽  
Vol 448-453 ◽  
pp. 1256-1259
Author(s):  
Feng Tan ◽  
Tai Quan Zhou
Keyword(s):  
Finite Element ◽  
Pore Water ◽  
Pore Water Pressure ◽  
Soil Depth ◽  
Water Pressure ◽  
Soft Soil ◽  
Excess Pore Pressure ◽  
Excess Pore Water Pressure ◽  
Consolidation Settlement ◽  
Excess Pore

The two-dimensional finite element model for subgrade consolidation settlement analysis within soft soil pile is developed using ABAQUS. The numerical simulation on a highway subgrade deformation is performed to study the variation of consolidation settlement and the excess pore water pressure distribution in the central location and the part under centerline of the embankment. The results show that settlement develops gradually with the increasing period of soil consolidation. The excess pore water pressure of deep subgrade soils under embankment centerline rise due to the increased load. After each soil layer was filled, the excess pore water pressure increased in the first and was stable later along with the increase of soil depth. After the embankment soil was filled completely, excess pore pressure dissipated with time developing until the completion of consolidation.

scholarly journals Analytical solution for one-dimensional consolidation of double-layered soil with exponentially time-growing drainage boundary

2018 ◽  
Vol 14 (10) ◽  
pp. 155014771880671 ◽  
Author(s):  
Wenbing Wu ◽  
Mengfan Zong ◽  
M Hesham El Naggar ◽  
Guoxiong Mei ◽  
Rongzhu Liang
Keyword(s):  
Analytical Solution ◽  
Pore Water ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Soil Layer ◽  
Excess Pore Water Pressure ◽  
One Dimensional ◽  
Present Solution ◽  
The One ◽  
Excess Pore

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.

Analysis of One-Dimensional Thermal Consolidation for Saturated Soil Considering Different Permeabilities

2014 ◽  
Vol 919-921 ◽  
pp. 641-644
Author(s):  
Cai Xia Guo ◽  
Rui Qian Wu
Keyword(s):  
Pore Water ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Saturated Soil ◽  
Excess Pore Water Pressure ◽  
One Dimensional ◽  
Consolidation Theory ◽  
Thermal Consolidation ◽  
The One ◽  
Excess Pore

Based on the analytical solutions of pore-water pressure and settlement. Problems of the one-dimensional thermal consolidation of saturated soil considering three different permeabilities were analyzed. Aiming at each permeability of thermal consolidation theory, compared with the corresponding Terzaghis consolidation theory, the one-dimensional thermal consolidation behaviour of saturated soil was analyzed in terms of excess pore-water pressure, the settlement. The results show that the permeability plays an important role in the thermal consolidation. The more permeability, the quicker pore-water pressure dissipation and the rate of settlement. Settlement of ground is more sensitive to temperature condition than the excess pore-water pressure. The behaviour of excess pore-water pressure in the process of thermal consolidation is very similar to the corresponding Terzaghis theory.

The Test Study to the Changes of Excess Pore Water Pressure during Precast Pile Construction

2012 ◽  
Vol 193-194 ◽  
pp. 1010-1013
Author(s):  
Shu Qing Zhao
Keyword(s):  
Pore Water ◽  
Clayey Soil ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Excess Pore Pressure ◽  
Soil Pressure ◽  
Excess Pore Water Pressure ◽  
Test Study ◽  
Excess Pore

The construct to precast pile in thick clayey soil can cause the accumulation of excess pore water pressure. The high excess pore pressure can make soil, buildings and pipes surrounded have large deflection, even make them injured. Combining with actual projects, this paper presents an in-situ model test on the changes of excess pore water pressure caused by precast pile construct. It is found that the radius of influence range for single pile driven is about 15m，the excess pore water pressure can reach or even exceed the above effective soil pressure, and there are two relatively stable stages.

The Influence Factors Analysis of Initial Excess Pore Water Pressure Caused by Construction of Shield Tunnels

2011 ◽  
Vol 268-270 ◽  
pp. 1295-1300
Author(s):  
Xin Jiang Wei ◽  
Wei Jun Chen ◽  
Gang Wei ◽  
An Yuan Liu
Keyword(s):  
Pore Water ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Influence Factors ◽  
Stress Transfer ◽  
Tunnel Lining ◽  
Excess Pore Water Pressure ◽  
Factors Analysis ◽  
Consolidation Settlement ◽  
Excess Pore

Excess pore water pressure caused by construction dissipated, resulting in consolidation settlement. The formula of initial excess pore water pressure around tunnel lining was deduced by stress relief theory, and its formula within the region of its distribution at any point was subsequently deduced by stress transfer theory. By comparing the measured data, shows that the calculated closed to the measured, and with the distance increased the initial excess pore water pressure decreased in a concave curve shape. When the depth of tunnel increased or the diameter decreased, would made initial excess pore water pressure between the tunnel bottom and tunnel center horizon around tunnel lining more different. At a certain depth, the mast initial excess pore water pressure above tunnel axis, away from the axis reduced; showing a similar PECK shape.

Analysis of One-Dimensional Consolidation of Non-Homogeneous Layer with Exponential Flow Law

2014 ◽  
Vol 638-640 ◽  
pp. 374-379 ◽  
Author(s):  
Feng Xi Zhou ◽  
Yi Ming He ◽  
Ying Xin
Keyword(s):  
Numerical Solution ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Decisive Role ◽  
Homogeneous Layer ◽  
One Dimensional ◽  
Governing Differential Equation ◽  
Degree Of Consolidation ◽  
Flow Law ◽  
The One

Based on exponential flow law, the analytical solution to the one-dimension consolidation governing differential equation was deduced when the laws of permeability and compressibility coefficients with depth can be expressed as exponential function. By finite difference method, the numerical solution of excess pore water pressure and degree of consolidation was obtained, then the reliability of numerical solution is verified by comparing numerical results with analytical results, and consolidation behavior of non-homogeneous layer with exponential flow law under various parameters is analyzed. The results showed that under the condition of the two-sided drainage, the heterogeneity of foundation consolidation of index of seepage speed depends on the index of the size and the size of the non-uniform parameters. That is when the index m is bigger, increase the permeability coefficient, reduce the compression coefficient, the consolidation is faster, but the inhomogeneous parameters are still play a decisive role.

Excess Pore Pressures During Undrained Clay Creep

1973 ◽  
Vol 10 (1) ◽  
pp. 12-24 ◽  
Author(s):  
Thomas L. Holzer ◽  
Kaare Höeg ◽  
Kandiah Arulanandan
Keyword(s):  
Pore Pressure ◽  
San Francisco ◽  
Pore Water ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Excess Pore Pressure ◽  
Time Behavior ◽  
Pore Pressures ◽  
Undrained Creep ◽  
Excess Pore

The objective of this presentation is to examine experimentally how the excess pore-water pressure is related to the mechanism for undrained creep of San Francisco Bay mud. The results are discussed in the context of creep mechanisms previously suggested in the literature and based on laboratory testing.It is found that shear strains occurring during undrained creep are directly related to a gradual but significant increase in excess pore pressure and, hence, reduction in effective stresses. The increase in magnitude of the pore pressure is, except immediately after the creep shear stress is applied, solely a function of the initial consolidation stress and consolidation period. The magnitude of the long-term build-up may be related to the amount of secondary compression which would occur during drained conditions. It increases with the organic content of the soil and decreases with the degree of remolding. The mechanism for the increase in pore-water pressure may be explained by drainage of water from micropores in the microstructure into the macrostructure.Unless one accounts for the increase in pore pressures during undrained creep, it is unlikely that one will be successful in formulating a generally valid mathematical model for stress–strain–strength–time behavior based on laboratory testing.

Sign in / Sign up

Export Citation Format

Share Document