scholarly journals Behavior of Nonplastic Silty Soils under Cyclic Loading

2014 ◽  
Vol 2014 ◽  
pp. 1-12 ◽  
Author(s):  
Nazile Ural ◽  
Zeki Gunduz
Keyword(s):  
Pore Pressure ◽  
Pore Water ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Clay Content ◽  
Cyclic Stress ◽  
Excess Pore Pressure ◽  
Stress Ratios ◽  
Silty Soils ◽  
Excess Pore

The engineering behavior of nonplastic silts is more difficult to characterize than is the behavior of clay or sand. Especially, behavior of silty soils is important in view of the seismicity of several regions of alluvial deposits in the world, such as the United States, China, and Turkey. In several hazards substantial ground deformation, reduced bearing capacity, and liquefaction of silty soils have been attributed to excess pore pressure generation during dynamic loading. In this paper, an experimental study of the pore water pressure generation of silty soils was conducted by cyclic triaxial tests on samples of reconstituted soils by the slurry deposition method. In all tests silty samples which have different clay percentages were studied under different cyclic stress ratios. The results have showed that in soils having clay content equal to and less than 10%, the excess pore pressure ratio buildup was quicker with an increase in different cyclic stress ratios. When fine and clay content increases, excess pore water pressure decreases constant cyclic stress ratio in nonplastic silty soils. In addition, the applicability of the used criteria for the assessment of liquefaction susceptibility of fine grained soils is examined using laboratory test results.

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.

scholarly journals Radial consolidation response upon the application and removal of vacuum and fill loading

2015 ◽  
Vol 52 (12) ◽  
pp. 2156-2162 ◽  
Author(s):  
Kourosh Kianfar ◽  
Buddhima Indraratna ◽  
Cholachat Rujikiatkamjorn ◽  
Serge Leroueil
Keyword(s):  
Pore Pressure ◽  
Pore Water ◽  
Pore Water Pressure ◽  
Axial Strain ◽  
Water Pressure ◽  
Vacuum Pressure ◽  
Excess Pore Pressure ◽  
Excess Pore Water Pressure ◽  
Removal Time ◽  
Excess Pore

This Note presents a laboratory study using a Rowe cell to compare the consolidation responses upon vacuum pressure and fill load application and removal. The influences of the duration of application and removal of fill load and vacuum pressures on radial consolidation were investigated using excess pore-water pressure, axial strain, and overconsolidation ratio. It is shown that the appropriate removal time for vacuum pressure can be determined based on excess pore pressure responses.

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.

scholarly journals Effect of Variable Confining Pressure on Cyclic Triaxial Behavior of K0-consolidated Soft Marine Clay

2018 ◽  
Vol 4 (4) ◽  
pp. 755
Author(s):  
Lei Sun
Keyword(s):  
Pore Water ◽  
Pore Water Pressure ◽  
Axial Strain ◽  
Water Pressure ◽  
Confining Pressure ◽  
Stress Path ◽  
Cyclic Stress ◽  
Marine Clay ◽  
Stress Ratios ◽  
Variable Confining Pressure

The effect of variable confining pressure (VCP) on the cyclic deformation and cyclic pore water pressure in K0-consolidated saturated soft marine clay were investigated with the help of the cyclic stress-controlled advanced dynamic triaxial test in undrained condition. The testing program encompassed three cyclic deviator stress ratios, CSR=0.189, 0.284 and 0.379 and three stress path inclinations ηampl=3,1 and 0.64. All tests with constant confining pressure (CCP) and variable confining pressure (VCP) have identical initial stress and average stress. The results were analyzed in terms of the accumulative normalized excess pore water pressure rqu recorded at the end of each stress cycle and permanent axial strain, as well as resilient modulus. Limited data suggest that these behavior are significantly affected by both of the VCP and CSR. For a given value of VCP, both of the pore water pressure rqu and permanent axial strains are consistently increase with the increasing values of CSR. However, for a given value of CSR, the extent of the influence of VCP and the trend is substantially depend on the CSR.

scholarly journals Mechanical response and pore pressure generation in granular filters subjected to uniaxial cyclic loading

2018 ◽  
Vol 55 (12) ◽  
pp. 1756-1768
Author(s):  
Jahanzaib Israr ◽  
Buddhima Indraratna
Keyword(s):  
Cyclic Loading ◽  
Pore Pressure ◽  
Pore Water ◽  
Mechanical Response ◽  
Pore Water Pressure ◽  
Axial Strain ◽  
Water Pressure ◽  
Internal Erosion ◽  
Excess Pore Water Pressure ◽  
Excess Pore

This paper presents results from a series of piping tests carried out on a selected range of granular filters under static and cyclic loading conditions. The mechanical response of filters subjected to cyclic loading could be characterized in three distinct phases; namely, (I) pre-shakedown, (II) post-shakedown, and (III) post-critical (i.e., the occurrence of internal erosion). All the permanent geomechanical changes such, as erosion, permeability variations, and axial strain developments, took place during phases I and III, while the specimen response remained purely elastic during phase II. The post-critical occurrence of erosion incurred significant settlement that may not be tolerable for high-speed railway substructures. The analysis revealed that a cyclic load would induce excess pore-water pressure, which, in corroboration with steady seepage forces and agitation due to dynamic loading, could then cause internal erosion of fines from the specimens. The resulting excess pore pressure is a direct function of the axial strain due to cyclic densification, as well as the loading frequency and reduction in permeability. A model based on strain energy is proposed to quantify the excess pore-water pressure, and subsequently validated using current and existing test results from published studies.

scholarly journals Pore Pressure Response to Groundwater Fluctuations in Saturated Double-Layered Soil

2015 ◽  
Vol 2015 ◽  
pp. 1-11 ◽  
Author(s):  
Hongwei Ying ◽  
Lisha Zhang ◽  
Kanghe Xie ◽  
Dazhong Huang
Keyword(s):  
Pressure Distribution ◽  
Pore Pressure ◽  
Dimensionless Parameter ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Layered Soil ◽  
Excess Pore Pressure ◽  
Groundwater Fluctuation ◽  
Excess Pore Pressures ◽  
Excess Pore

Analytical solutions are developed for one-dimensional consolidation of double-layered saturated soil subjected to groundwater fluctuations. The solutions are derived by an explicit mathematical procedure using Duhamel’s theorem in conjunction with a Fourier series, when groundwater fluctuation is described by a general time-dependent function and assumed to be the pore water pressure variations at the upper boundary. Taking as an example the harmonic groundwater fluctuation, the relevant response of the excess pore water pressure is discussed in detail, and the main influencing factors of the excess pore pressure distribution are analyzed. A dimensionless parameterθhas been introduced because it significantly affects the phase and the amplitude of excess pore pressures. The influences of the coefficients of permeability and compressibility of soil on the excess pore pressure distribution are different and cannot be incorporated into the coefficient of consolidation in double-layered soil. The relative permeability ratio of two clayey soils also plays an important role on the curves of the distributions of the excess pore pressures. The effects of the thickness of the soil layer on the excess pore pressure distribution should be considered together with the dimensionless parameterθand the permeability and compressibility of the double-layered soil system.

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 Contribution of Pumping Action of Wave-Induced Pore-Pressure Response to Development of Fluid Mud Layer

2019 ◽  
Vol 7 (9) ◽  
pp. 317 ◽  
Author(s):  
Yang ◽  
Zhu ◽  
Liu ◽  
Sun ◽  
Ling ◽  
...  
Keyword(s):  
Pore Pressure ◽  
Fine Particles ◽  
Pore Water Pressure ◽  
Theoretical Calculations ◽  
Water Pressure ◽  
Pressure Response ◽  
Excess Pore Pressure ◽  
Pore Pressure Response ◽  
Wave Induced ◽  
Excess Pore

To investigate the vertical migration response of fine sediments, the pore pressure response of the silty seabed under the action of waves was tested. Under the action of waves, there is an obvious pumping phenomenon in the sludge accumulated by pore pressure. The excess pore water pressure caused by the waves in the seabed is unevenly distributed with respect to depth and there is an extreme value of up to 1.19 kPa. The pressure affects the liquefaction properties of the sludge. According to instantaneous-liquefaction judgment, the liquefaction of surface soil occurs, but the soil is not completely liquefied. Using theoretical calculations, the vertical source supply of floating mud development was analyzed. The pumping effect of the wave-induced excess pore pressure manifests in two aspects, as follows: (1) The centralized migration of splitting channels, which is visible to the naked eye, and (2) the general migration of fine particles between particle gaps at the mesoscopic level, which accounts for up to 22.2% of the migration of fine particles.

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.

Piezocone testing in underconsolidated clay

1989 ◽  
Vol 26 (4) ◽  
pp. 563-567 ◽  
Author(s):  
Yasuo Tanaka ◽  
Toshihiko Sakagami
Keyword(s):  
Pore Water ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Excess Pore Pressure ◽  
Special Importance ◽  
Tip Resistance ◽  
Degree Of Consolidation ◽  
Excess Pore Pressures ◽  
Marine Clays ◽  
Excess Pore

This paper describes the results of piezocone testing that was carried out in underconsolidated soft marine clay in Osaka Bay. The obtained profiles of the tip resistance and the pore-water pressure were quite different from those for clay strata of normally consolidated state. It was apparent that a different approach is needed to interpret the test results for underconsolidated clay. The dissipation tests with the piezocone were performed at different elevations and indicated the excess pore-water pressures remaining in the stratum.The depth profile of excess pore pressure of underconsolidated clay is of special importance to the understanding of the degree of consolidation of the stratum. An effort was made in this paper to assess the excess pore pressures remaining in the clay based on the piezocone data obtained during penetration. An examination was made of available piezocone data of similar marine clays, of both normally consolidated and underconsolidated states. Based on this, a method was proposed for predicting the profile of pore-water pressure in underconsolidated clay using the piezocone data obtained during penetration. Key words: piezocone, field test, underconsolidated clay, excess pore-water pressure, interpretation.

Sign in / Sign up

Export Citation Format

Share Document