scholarly journals Excess pore pressure in a poroelastic seabed saturated with a compressible fluid

1994 ◽  
Vol 31 (6) ◽  
pp. 989-1003 ◽  
Author(s):  
Z.Q. Yue ◽  
A.P.S. Selvadurai ◽  
K.T. Law
Keyword(s):  
Pore Pressure ◽  
Fluid Pressure ◽  
Offshore Structures ◽  
Pore Fluid ◽  
Excess Pore Pressure ◽  
Soil Consolidation ◽  
Normal Surface ◽  
Compressible Pore Fluid ◽  
Poroelastic Seabed ◽  
Excess Pore

This paper presents an analytical investigation on the excess pore-fluid pressure in a finite seabed layer by taking into account the influence of a compressible pore fluid. The seabed layer is modeled as a poroelastic layer saturated with a compressible pore fluid and resting on a rough, rigid impermeable base. The surface of the poroelastic seabed layer is either completely pervious or completely impervious, and subjected to a normal surface traction induced by offshore structures. The paper presents analytical and numerical results to illustrate the time-dependent behaviour of excess pore pressure in the poroelastic seabed. The results demonstrate that the presence of a compressible pore fluid reduces the generation of excess pore pressure in the poroelastic seabed layer. Key words : excess pore pressure, poroelastic seabed layer, soil consolidation, compressible pore fluid, integral transforms.

scholarly journals A semi-empirical model to predict excess pore pressure generation in partially saturated sand

2020 ◽  
Vol 195 ◽  
pp. 02026
Author(s):  
Mousavi Sayedmasoud ◽  
Majid Ghayoomi
Keyword(s):  
Pore Pressure ◽  
Empirical Model ◽  
Pressure Ratio ◽  
Pore Fluid ◽  
Excess Pore Pressure ◽  
Saturated Soils ◽  
Partial Saturation ◽  
Liquefaction Resistance ◽  
Semi Empirical ◽  
Excess Pore

Past studies revealed that excess pore pressure generation due to cyclic loading is highly governed by induced strains, volumetric deformation potential of soil, number of cycles, and bulk stiffness of pore fluid. It is well established that partial saturation can significantly reduce bulk stiffness of pore fluid and consequently excess pore pressure generation during seismic loading. On the basis of that, a number of researchers have investigated induced partial saturation as an effective soil improvement technique to increase the liquefaction resistance of fully saturated soils. This paper focuses on development of a semi- empirical model to interpret the effects of partial saturation on the excess pore pressure generation in sands. In this regard, an existing strain based excess pore pressure ratio (ru) prediction model originally developed for fully saturated soils was modified to incorporate the effect of partial saturation on the excess pore pressure generation. The literature data as well as data from a series of strain-controlled direct simple shear test were used to evaluate the reliability of the proposed equation in predicting the excess pore pressure ratio in partial saturation condition.

Study on Different Methods of Computing Consolidation Coefficient by Excess Pore Pressure Dissipation Datum on CPTU

2011 ◽  
Vol 90-93 ◽  
pp. 680-683
Author(s):  
Yan Chun Tang ◽  
Gao Tou Meng ◽  
Qiu Feng Mao
Keyword(s):  
Pore Pressure ◽  
Strain Path ◽  
Engineering Application ◽  
Excess Pore Pressure ◽  
Soil Consolidation ◽  
Application Research ◽  
Empirical Coefficient ◽  
Consolidation Coefficient ◽  
Coefficient Method ◽  
Excess Pore

Based on the different methods of computing the soil consolidation coefficient by excess pore pressure dissipation datum on CPTU, through computing the soil consolidation coefficient by different methods on the datum of CPTU model test and CPTU application research on Pearl River Delta, the applicability on different methods of computing consolidation coefficient by CPTU has been studied. The results show that on the computing value of consolidation coefficient, TB10041-2003 is more conservative; because of poor applicability on Strain Path Method and difficulty for obtaining t100 on Zhu-Xiaolin Method and α on Empirical Coefficient Method, some results can not be solved, so Strain Path Method and Zhu-Xiaolin Method and Empirical Coefficient Method are poor in engineering application; the computing way and the computing result on Zhang-Chenghou Method are similar with Torstensson Method with 50% consolidation degree. The achieved result can provide a foundation for further study for CPTU application research.

scholarly journals Comparison of Coupled and Uncoupled Consolidation Equations Using Finite Element Method in Plane-Strain Condition

2016 ◽  
Vol 2 (8) ◽  
pp. 375-388 ◽  
Author(s):  
Mohamadtaqi Baqersad ◽  
Abbas Eslami Haghighat ◽  
Mohammadali Rowshanzamir ◽  
Hamid Mortazavi Bak
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Pore Pressure ◽  
Effective Stress ◽  
Excess Pore Pressure ◽  
Soil Deformation ◽  
Soil Consolidation ◽  
Time Step ◽  
Excess Pore ◽  
Element Method

In the current paper, the consolidation settlement of a strip footing over a finite layer of saturated soil has been studied using the finite element method. In Biot’s coupled consolidation equations, the soil deformation and excess pore pressure are determined simultaneously in every time step which refers to the hydro-mechanical coupling. By considering a constant total stress throughout the time and by assuming that volume strain is a function of isotropic effective stress, uncoupled consolidation equations can be obtained using coupled consolidation equations. In these uncoupled equations, excess pore pressure and deformation are determined separately. In this approach, the excess pore pressure can be identified in the first stage. Using the calculated excess pore pressure, the soil deformation is determined through effective stress-strain analyses. A computer code was developed based on coupled and uncoupled equations that are capable of performing consolidation analyses. To verify the accuracy of these analyses, the obtained results have been compared with the precise solution of Terzaghi’s one-dimensional consolidation theory. The capability of these two approaches in estimation of pore water pressure and settlement and to show Mandel-Crayer’s effect in soil consolidation is discussed. Then, the necessity of utilizing coupled analyses for evaluating soil consolidation analysis was investigated by comparing the coupled and uncoupled analyses results.

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.

scholarly journals Factors affecting seismic response of submarine slopes

2006 ◽  
Vol 6 (1) ◽  
pp. 97-107 ◽  
Author(s):  
G. Biscontin ◽  
J. M. Pestana
Keyword(s):  
Pore Pressure ◽  
Slope Failure ◽  
Site Response ◽  
Soil Mass ◽  
Offshore Structures ◽  
Constitutive Law ◽  
Excess Pore Pressure ◽  
Factors Affecting ◽  
Motion Characteristics ◽  
Excess Pore

Abstract. The response of submerged slopes on the continental shelf to seismic or storm loading has become an important element in the risk assessment for offshore structures and "local" tsunami hazards worldwide. The geological profile of these slopes typically includes normally consolidated to lightly overconsolidated soft cohesive soils with layer thickness ranging from a few meters to hundreds of meters. The factor of safety obtained from pseudo-static analyses is not always a useful measure for evaluating the slope response, since values less than one do not necessarily imply slope failure with large movements of the soil mass. This paper addresses the relative importance of different factors affecting the response of submerged slopes during seismic loading. The analyses use a dynamic finite element code which includes a constitutive law describing the anisotropic stress-strain-strength behavior of normally consolidated to lightly overconsolidated clays. The model also incorporates anisotropic hardening to describe the effect of different shear strain and stress histories as well as bounding surface principles to provide realistic descriptions of the accumulation of the plastic strains and excess pore pressure during successive loading cycles. The paper presents results from parametric site response analyses on slope geometry and layering, soil material parameters, and input ground motion characteristics. The predicted maximum shear strains, permanent deformations, displacement time histories and maximum excess pore pressure development provide insight of slope performance during a seismic event.

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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