Pore-Water Pressure and Creep in One-Dimensional Compression of Silt

1966 ◽  
pp. 316-332
Author(s):  
E. Schultze ◽  
J. Krause
Keyword(s):  
Pore Water ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
One Dimensional

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.

Analysis of One-Dimensional Thermal Consolidation of Saturated Soil with and without Thermo-Mechanical Coupling

2012 ◽  
Vol 594-597 ◽  
pp. 335-338
Author(s):  
Xue Shen ◽  
Rui Qian Wu
Keyword(s):  
Pore Water ◽  
Pore Water Pressure ◽  
Saturated Porous Medium ◽  
Water Pressure ◽  
Saturated Soil ◽  
Excess Pore Water Pressure ◽  
One Dimensional ◽  
Mechanical Coupling ◽  
Thermal Consolidation ◽  
Excess Pore

Based on a one-dimensional thermal consolidation formulation with and without thermo-mechanical coupling of saturated porous medium, problems of one-dimensional thermal consolidation of saturated soil were investigated. For the condition with instantaneous constant surface temperature and uniform initial pore-pressure, analytical solutions of excess pore-water pressure and temperature increment were derived respectively by the method of finite Fourier transform and inverse transform. A relevant computer program was developed, and the excess pore-water pressure was compared in detail. The results show that the thermo-mechanical coupling item in the thermal consolidation equation can be ignored.

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.

scholarly journals Study on Electroosmosis Consolidation of Punctiform Electrode Unit

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Xiaoyu Yang ◽  
Yongbin Xie ◽  
Jianhua Dong ◽  
Guosheng Liu ◽  
Yalin Zheng
Keyword(s):  
Finite Element ◽  
Pore Water ◽  
Potential Field ◽  
Potential Distribution ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Two Dimensional ◽  
Dimensional Model ◽  
One Dimensional ◽  
Electric Potential Field

In the electroosmosis method, when the distance between the opposite electrode and the same electrode is equal, the two-dimensional effect of electroosmotic consolidation is significant, and the use of one-dimensional model will overestimate the potential gradient, making the calculated pore pressure value too large. Aiming at this problem, according to the electrode arrangement rule and the minimum composition, a punctiform electrode unit model is proposed, and electroosmotic experiments are carried out on the symmetric and asymmetric unit models. The two-dimensional electroosmotic consolidation governing equation of the punctiform electrode unit is established. The electric potential field of the electrode unit and the finite element form of the electroosmotic consolidation equation are given by the Galerkin method. The PyEcFem finite-element numerical library is developed using Python programming to calculate. The research results show the following: (1) The two-dimensional effect of the potential field distribution of the punctiform electrode unit is significant. The reduction of spacing of the same nature electrode in the symmetrical unit can make the potential distribution close to a uniform electric field. The asymmetry prevents the electric potential field distribution from being reduced to a one-dimensional model. (2) The number of anodes will affect the electroosmosis effect of the soil. The more the anodes, the better the electroosmosis reinforcement effect of the soil, and the distribution of negative excess pore water pressure will be more uniform. (3) In the early stage of electroosmosis, the more the drainage boundaries, the faster the generation of negative pore pressure, but in the middle and late stages of electroosmosis, the potential value becomes the decisive factor, and the amplitude of negative pore water pressure in asymmetric units is higher than that in symmetric units. The potential distribution will not affect the degree of consolidation but will affect the extreme pore water pressure.

scholarly journals Analytical Solution and Application for One-Dimensional Consolidation of Tailings Dam

2018 ◽  
Vol 2018 ◽  
pp. 1-9
Author(s):  
Hai-ming Liu ◽  
Gan Nan ◽  
Wei Guo ◽  
Chun-he Yang ◽  
Chao Zhang
Keyword(s):  
Differential Equation ◽  
Partial Differential Equation ◽  
Pore Water ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Great Influence ◽  
Tailings Dam ◽  
Partial Differential ◽  
One Dimensional ◽  
The Stability

The pore water pressure of tailings dam has a very great influence on the stability of tailings dam. Based on the assumption of one-dimensional consolidation and small strain, the partial differential equation of pore water pressure is deduced. The obtained differential equation can be simplified based on the parameters which are constants. According to the characteristics of the tailings dam, the pore water pressure of the tailings dam can be divided into the slope dam segment, dry beach segment, and artificial lake segment. The pore water pressure is obtained through solving the partial differential equation by separation variable method. On this basis, the dissipation and accumulation of pore water pressure of the upstream tailings dam are analyzed. The example of typical tailings is introduced to elaborate the applicability of the analytic solution. What is more, the application of pore water pressure in tailings dam is discussed. The research results have important scientific and engineering application value for the stability of tailings dam.

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.

One-dimensional consolidation theory: unsaturated soils

1979 ◽  
Vol 16 (3) ◽  
pp. 521-531 ◽  
Author(s):  
Delwyn G. Fredlund ◽  
Jamshed U. Hasan
Keyword(s):  
Partial Differential Equations ◽  
Differential Equations ◽  
Pore Water ◽  
Unsaturated Soils ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Partial Differential ◽  
Total Load ◽  
One Dimensional ◽  
Consolidation Theory

A one-dimensional consolidation theory is presented for unsaturated soils. The assumptions made are in keeping with those used in the conventional theory of consolidation for saturated soils, with the additional assumption that the air phase is continuous. Two partial differential equations are derived to describe the transient processes taking place as a result of the application of a total load to an unsaturated soil.After a load has been applied to the soil, air and water flow simultaneously from the soil until equilibrium conditions are achieved. The simultaneous solution of the two partial differential equations gives the pore-air and pore-water pressures at any time and any depth throughout the soil. Two families of dimensionless curves are generated to show the pore-air and pore-water dissipation curves for various soil properties.For the case of an applied total load, two equations are also derived to predict the initial pore-air and pore-water pressure boundary conditions. An example problem demonstrates the nature of the results.

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.

TIME TO THE END OF PRIMARY CONSOLIDATION (EOP) OF SOFT CLAYEY SOILS: CONCERNING THE EFFECT OF ATTERBERG’S LIMIT AND CYCLIC LOADING HISTORY

2019 ◽  
Vol 128 (2B) ◽  
pp. 29-41
Author(s):  
Trần Thanh Nhàn
Keyword(s):  
Cyclic Loading ◽  
Pore Water ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Clayey Soils ◽  
Loading History ◽  
Cyclic Shear ◽  
Wide Range ◽  
Primary Consolidation ◽  
Time Required

In order to observe the end of primary consolidation (EOP) of cohesive soils with and without subjecting to cyclic loading, reconstituted specimens of clayey soils at various Atterberg’s limits were used for oedometer test at different loading increments and undrained cyclic shear test followed by drainage with various cyclic shear directions and a wide range of shear strain amplitudes. The pore water pressure and settlement of the soils were measured with time and the time to EOP was then determined by different methods. It is shown from observed results that the time to EOP determined by 3-t method agrees well with the time required for full dissipation of the pore water pressure and being considerably larger than those determined by Log Time method. These observations were then further evaluated in connection with effects of the Atterberg’s limit and the cyclic loading history.

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