scholarly journals The Liquefaction Behavior of Poorly Graded Sands Reinforced with Fibers

2018 ◽  
Vol 2018 ◽  
pp. 1-14 ◽  
Author(s):  
Eyyüb Karakan ◽  
Tuğba Eskişar ◽  
Selim Altun
Keyword(s):  
Pore Water ◽  
Fiber Length ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Fiber Content ◽  
Excess Pore Pressure ◽  
Triaxial Tests ◽  
Strong Impact ◽  
Fiber Reinforced ◽  
Excess Pore

This study focuses on the performance of fibers, improving the resistance to liquefaction in loose sands, medium sands, and dense sands in Izmir, Turkey. A systematic testing schedule consisting of cyclic triaxial tests was held under stress-controlled and undrained conditions on saturated sand specimens with and without fiber reinforcements. The major parameters having effects on the dynamic behavior such as fiber content, fiber length, and relative density on the liquefaction behavior and the excess pore water pressure developments of specimens with and without fibers were investigated. If the fiber content or the fiber length was increased in the specimens, higher number of loading cycles was needed in order to experience the liquefaction of sands. The reinforcement effect in medium-dense specimens was found to be apparently distinctive compared to loose specimens. The curves of pore water pressures and shear strains were achieved for the fiber-reinforced sands. The boundaries of pore water pressure curves presented in the literature on the clean sands were utilized in comparison with the pore water pressure curves of fiber-reinforced sands of this study. As a conclusion, the results presented in this study are useful to develop insight into the behavior of clean and fiber-reinforced sands under seismic loading conditions. Based on the test results, it was found that the number of loading cycles had a strong impact on the excess pore pressure generation.

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.

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 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.

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 Mechanical response of fiber-reinforced sand under cyclic loading

2020 ◽  
Vol 198 ◽  
pp. 01048
Author(s):  
Gang Li ◽  
Jinli Zhang ◽  
Jia Liu
Keyword(s):  
Cyclic Loading ◽  
Fiber Length ◽  
Mechanical Response ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Dynamic Strength ◽  
Fiber Content ◽  
Dynamic Shear Modulus ◽  
Fiber Reinforced ◽  
Reinforced Sand

Based on the consolidated undrained test under cyclic loading, the mechanical response of fiber-reinforced sand under cyclic loading was studied by varying fiber content (0.2% and 0.4%), fiber length (7 mm and 13 mm), and cyclic stress ratio (0.22, 0.24 and 0.26), and the effects of fiber content and fiber length on the excess pore water pressure, dynamic strength and dynamic shear modulus were discussed. The results showed that with the increasing of fiber content, the dynamic strength and liquefaction resistance increased, whereas the accumulation rate of excess pore water pressure decreased. The reduction rate of dynamic shear modulus decreased with the increasing of fiber length, and the dynamic strength decreased with the increasing of cyclic stress ratio, which indicated that the dynamic characteristics of fiber-reinforced sand were better than that of unreinforced sand.

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.

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.

Numerical Analysis of MMP Piling with Wet-Jetting Method

2012 ◽  
Vol 446-449 ◽  
pp. 1718-1722
Author(s):  
Yao Yao Chen ◽  
De An Sun
Keyword(s):  
Pore Water ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Excess Pore Pressure ◽  
Three Dimension ◽  
Three Dimensional Model ◽  
Excess Pore Water Pressure ◽  
Modified Cam Clay ◽  
Excess Pore

MMP pile is a method of foundation treatment, and driving pile brings the excess pore water pressure in the surrounding subgrade. By using a software ABAQUS to build a three-dimensional model, the process of MMP pile driven at a site of railway foundation in Shanghai is simulated using theory of Biot consolidation and modified Cam-clay model with three-dimension effect being considered. The changes in the excess pore pressure are obtained. Comparing the computed results with measured results in situ shows that the computed excess pore water pressure is consistency with that measured from in situ.

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