scholarly journals Undrained monotonic and cyclic shear response and particle crushing of silica sand at low and high pressures

2017 ◽  
Vol 54 (2) ◽  
pp. 207-218 ◽  
Author(s):  
Masayuki Hyodo ◽  
Yang Wu ◽  
Noritaka Aramaki ◽  
Yukio Nakata
Keyword(s):  
Pore Water ◽  
Stress Ratio ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Confining Pressure ◽  
Cyclic Stress ◽  
Silica Sand ◽  
Particle Crushing ◽  
Cyclic Stress Ratio ◽  
Confining Pressures

A series of undrained monotonic and cyclic triaxial tests were performed on silica sand at two initial densities and different confining pressures from 0.1 to 5 MPa to investigate their shear response and crushing behaviour. The influence of particle crushing on the undrained shear strength and pore-water pressure was examined. To clarify the evolution of particle crushing, undrained monotonic and cyclic tests were terminated at several distinctive stages and sieving analysis tests were subsequently performed on the tested specimens. In the undrained monotonic test, specimens exhibited remarkable dilation behaviour and experienced no apparent particle crushing at low confining pressures. An increase in the mean stress suppressed the dilatancy due to a faster increase of the pore-water pressure, giving rise to the occurrence of particle crushing. In the undrained cyclic test, a higher confining pressure and cyclic stress ratio resulted in a much higher relative breakage. At a specific cyclic stress ratio, the relative breakage increased as the cyclic loading progressed. The confining pressure and shear strain amplitude played a significant role in controlling the evolution of particle breakage. The correlation between the relative breakage and plastic work for specimens under isotropic consolidation, undrained monotonic, and cyclic loadings has been validated experimentally.

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.

Study of Variation of Soil Stress State Based on the Curve of Normalized Strain- Pore Water Pressure

2013 ◽  
Vol 275-277 ◽  
pp. 295-298
Author(s):  
Gang Yang ◽  
Qing Yang ◽  
Wen Hua Liu
Keyword(s):  
Pore Water ◽  
Pore Water Pressure ◽  
Axial Strain ◽  
Water Pressure ◽  
Cyclic Stress ◽  
Cyclic Stress Ratio ◽  
Cycle Number ◽  
Soil Stress ◽  
Critical Cyclic Stress Ratio ◽  
Versus Strain

The cyclic behavior of normally consolidated silty clays was investigated by conducting a series of cyclic simple shear tests on one-dimensionally and isotropically consolidated reconstituted samples. The critical cyclic stress ratio was obtained by the normalized axial strain. Based on hysteretic curve of pore water pressure versus strain, dynamic characteristics of silty clay were investigated. The results showed that with increasing of cyclic loading, soil stress state can be divided into steady state, critical state and failure state based on the critical cyclic stress ratio. The hysteresis curve of pore water pressure versus strain was divided into two parts by cross point A. Compared with two parts, the variation law was obtained. When the upper part area was bigger than the lower part area, pore water pressure and axial strain continuously increase with cycle number; when the upper part area was smaller than the lower part area, pore water pressure and axial strain tended to be steady with cycle number.

scholarly journals A SIMPLE SHAKING TABLE TEST TO MEASURE LIQUEFACTION POTENTIAL OF PRAMBANAN AREA, YOGYAKARTA, INDONESIA

2021 ◽  
Vol 11 (3) ◽  
pp. 89-108
Author(s):  
Lindung Zalbuin Mase ◽  
Teuku Faisal Fathani ◽  
Agus Darmawan Adi
Keyword(s):  
Dynamic Load ◽  
Stress Ratio ◽  
Shaking Table Test ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Pressure Ratio ◽  
Cyclic Stress ◽  
Shaking Table ◽  
Liquefaction Potential ◽  
Cyclic Stress Ratio

This paper presents the experimental study of liquefaction potential for sandy soil in Prambanan Area, Yogyakarta, Indonesia, which underwent liquefaction due to the Mw 6.3 Jogja Earthquake on May 27, 2006. Shaking table tests considering the variation of acceleration and shaking duration were performed to investigate the liquefaction potential of sand. The liquefaction time stages including time to start liquefaction, time to start pore pressure dissipation, and liquefaction duration were observed. The percentage of liquefaction duration increase, the excess pore water pressure ratio and the required time to generate liquefaction, and the effect of applied acceleration to cyclic stress ratio, were also presented. The results showed that the sand could undergo liquefaction under the variation of dynamic load. The variation of dynamic load significantly influenced the time stages of liquefaction, the increase of liquefaction duration percentage and cyclic stress ratio. The results also exhibited that the larger applied acceleration and the longer shaking duration means the longer liquefaction duration and the larger liquefaction potential. In general, the result could bring the recommendation to the liquefaction countermeasure for Prambanan Area.

Liquefaction-Induced Ground Deformation of Slopes Using Geostudio2007 Software Program

2011 ◽  
Vol 261-263 ◽  
pp. 1303-1308
Author(s):  
Baydaa Hussain Maula ◽  
Ling Zhang
Keyword(s):  
Stress Ratio ◽  
Pore Water Pressure ◽  
Ground Deformation ◽  
Water Pressure ◽  
Slope Angle ◽  
Cyclic Stress ◽  
Lateral Spreading ◽  
Severe Damage ◽  
Cyclic Stress Ratio ◽  
Earthquake Record

Liquefaction phenomenon which has produced severe damage all over the world was studied under earthquake record of 0.5g; one of the major effects of liquefaction is lateral spreading. Lateral spreading occurs in sloping grounds and can cause serious damage to structures and lifelines. The objective of this paper is to study the effect of earthquake shaking on soils and slope stability using Geo Studio software 2007. The applicability of the analysis is demonstrated by analysis various slope and embankments subjected to earthquake shaking. This study investigated the effect of embankment slope angle and its geometry on liquefaction. Pore water pressure can be increased by 100% to 35% as β ranged from 35ͦ to 45ͦ respectively, it can see that liquefaction zone induced by earthquake can eliminate as flattering slope and mean while reduced lateral speared displacement. Three case studies are providing to evaluation cyclic stress ratio (CSR) due to earthquake and lateral speared for soils.

scholarly journals Analisis Potensi Likuefaksi pada Tanah Pasir Akibat Gempa (Studi Kasus Mataram, Nusa Tenggara Barat)

2021 ◽  
Vol 6 (3) ◽  
pp. 166
Author(s):  
Gea Nurbani ◽  
Yuki Achmad Yakin
Keyword(s):  
Stress Ratio ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Standard Penetration Test ◽  
Cyclic Stress ◽  
Resistance Ratio ◽  
Penetration Test ◽  
Cyclic Stress Ratio ◽  
Cyclic Resistance ◽  
Cyclic Resistance Ratio

ABSTRAKPada hari Minggu, 5 Agustus 2018 pukul 19:46 WITA, gempa bumi mengguncang wilayah Labuan, Lombok, Nusa Tenggara Barat dengan skala magnitudo M7,0. Akibat guncangan tersebut, terjadi peristiwa likuefaksi di sebagian wilayah Provinsi Nusa Tenggara Barat dan menimbulkan kerusakan yang signifikan. Peristiwa likuefaksi dapat terjadi apabila mengalami peningkatan tekanan air pori yang dipicu oleh gempa bumi sehingga mengakibatkan tanah kehilangan kekakuan dan kuat geser tanah. Likuefaksi pada umumnya terjadi pada tanah pasir lepas dengan kondisi jenuh air. Dalam menganalisis potensi terjadinya likuefaksi di lokasi penelitian, digunakan nilai percepatan puncak di batuan dasar (PGA) sebesar 4,13 m/s2dan menggunakan data tanah hasil pengujian Standard Penetration Test (SPT). Hasil perbandingan antara ketahanan tanah atau Cyclic Resistance Ratio (CRR) dengan kemampuan tanah terlikuefaksi atau Cyclic Stress Ratio (CSR) menunjukkan bahwa likuefaksi terjadi pada rata-rata kedalaman 5,5 m – 19.5 m.Kata kunci: likuefaksi, cyclic stress ratio (CSR), cyclic resistance ratio (CRR), faktor keamanan (FK) ABSTRACTOn Sunday, August 5 2018 at 19:46 WITA, an earthquake has shook Labuan, Lombok, West Nusa Tenggara with magnitude 7.0 scale. As a result of the earthquake, liquefaction occurred in several regions of West Nusa Tenggara and caused severe damage. Liquefaction can occure when an increase in pore water pressure is triggered by an earthquake, which causes the soil losing its shear strength and stiffness. Liquefaction mostly occured in sand loose and saturated condition. Analysis of liquefaction based on Peak Ground Acceleration (PGA) at the research site 4.13 m/s2 were done according to the data of SPT (Standard Penetration Test). By comparing the value of soil resistance to liquefaction or Cyclic Resistance Ratio (CRR) and the ability of soil to be liquefied or Cyclic Stress Ratio (CSR), the analysis shows the soil in that area are liquefied at depth of 5.5 m – 19.5 m.Keywords: liquefaction, cyclic stress ratio (CSR), cyclic resistance ratio (CRR), safety of factor (SF)

scholarly journals Experimental Study on the Variation Law of Excess Pore Water Pressure at the Bottom of the Foundation Pit for Excavation

2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Qizhi Hu ◽  
Qiang Zou ◽  
Zhigang Ding ◽  
Zhaodong Xu
Keyword(s):  
Pore Water ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Soft Soil ◽  
Confining Pressure ◽  
Deep Foundation ◽  
Foundation Pit ◽  
Excess Pore Water Pressure ◽  
Accurate Expression ◽  
Excess Pore

The excavation unloading of deep foundation pits in soft soil areas often produces negative excess pore water pressure. The rebound deformation of soil on the excavation surface of the foundation pit can be predicted reliably through the accurate expression of relevant variation laws. In combination with the principle of effective stress and the general equation of unidirectional seepage consolidation, an equation for calculating the rebound deformation from the bottom in the process of foundation pit excavation unloading was obtained. Additionally, a triaxial unloading test was adopted to simulate the excavation unloading processes for actual foundation pit engineering. After studying the variation law of the excess pore water pressure generated by excavation unloading, it was found that the negative excess pore water pressure increased with increasing unloading rate, while the corresponding peak value decreased with increasing confining pressure. The equation for rebound calculation was verified through a comparison with relevant measured data from actual engineering. Therefore, it is considered that the equation can reliably describe the rebound deformation law of the base. This paper aims to guide the design and construction of deep foundation pits in soft soil areas.

scholarly journals Bench-Scale Experiments on Effects of Pipe Flow and Entrapped Air in Soil Layer on Hillslope Landslides

Geosciences ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 138 ◽  
Author(s):  
Yasutaka Tanaka ◽  
Taro Uchida ◽  
Hitoshi Nagai ◽  
Hikaru Todate
Keyword(s):  
Water Supply ◽  
Pore Water ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Soil Layer ◽  
Silica Sand ◽  
Bench Scale ◽  
Drainage Capacity ◽  
Entrapped Air ◽  
Model Slope

Soil pipes are commonly found in landslide scarps, and it has been suggested that build-up of pore water pressure due to clogged soil pipes influences landslide initiation. Several researchers have also suggested that entrapped air in the soil layer increases the pore water pressure. We carried out bench-scale model experiments to investigate the influence of soil pipes and entrapped air on the build-up of pore water pressure. We installed a water supply system consisting of an artificial rainfall simulator, and used a water supply tank to supply water to the model slope and artificial pipe. We used two types of artificial pipe: A straight pipe, and a confluence of three pipes. Furthermore, we placed a layer of silica sand on top of the model slope to investigate the effect of entrapped air in the soil layer on the build-up of pore water pressure. Silica sand is finer than the sand that we used for the bulk of the model slope. Our results indicate that, although artificial pipes decrease the pore water pressure when the amount of water supplied was smaller than the pipe drainage capacity, the pore water pressure increased when the water supply was too large for the artificial pipe to drain. In particular, the confluence of pipes increased the pore water pressure because the water supply exceeded the drainage capacity. The results also indicate that entrapped air increases the pore water pressure in the area with relatively low drainage capacity, too. Based on these results, we found that although soil pipes can drain a certain amount of water from a soil layer, they can also increase the pore water pressure, and destabilize slopes. Furthermore, entrapped air enhances the trend that the pore water pressure can increase in the area with relatively low drainage capacity, as pore water pressure increases when too much water is supplied, and the artificial pipe cannot drain all of it.

Laboratory study on subgrade fluidization under undrained cyclic triaxial loading

2020 ◽  
Vol 57 (11) ◽  
pp. 1767-1779 ◽  
Author(s):  
Buddhima Indraratna ◽  
Mandeep Singh ◽  
Thanh Trung Nguyen ◽  
Serge Leroueil ◽  
Aruni Abeywickrama ◽  
...  
Keyword(s):  
Stress Ratio ◽  
Confining Pressure ◽  
Cyclic Stress ◽  
Triaxial Tests ◽  
Loading Conditions ◽  
Cyclic Triaxial ◽  
Cyclic Stress Ratio ◽  
Upward Migration ◽  
Efficient Operation ◽  
Mud Pumping

A long-term issue that has hampered the efficient operation of heavy-haul tracks is the migration of fluidized fines from the shallow soft subgrade to the overlying ballast, i.e., mud pumping. This paper presents a series of undrained cyclic triaxial tests where realistic cyclic loading conditions were simulated at low confining pressure that is typical of shallow subgrade beneath a ballast track. Subgrade soil specimens with a low-plasticity index collected from a field site with recent history of mud pumping were tested at frequencies from 1.0 to 5.0 Hz and a cyclic stress ratio (CSR) from 0.1 to 1.0. The experimental results indicate that under adverse loading conditions of critical cyclic stress ratio (CSRc) and frequency, there is upward migration of moisture and the finest particles towards the specimen top and this causes the uppermost part of the soil specimen to soften and fluidize. Conversely, a smaller value of CSR tends to maintain stability of the specimen despite the increasing number of loading cycles. It is noteworthy that for any given combination of CSR and frequency, the relative compaction has a significant influence on the cyclic behaviour of the soil and its potential for fluidization.

Experimental technique for visualization of aquitard compaction over aquifer caused by excess pumping

2020 ◽  
Author(s):  
Kazunori Tabe ◽  
Masaatsu Aichi
Keyword(s):  
Pore Water ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Three Dimensional ◽  
Physical Modelling ◽  
Pumping Test ◽  
Silica Sand ◽  
Clay Layer ◽  
Synthetic Clay ◽  
Transparent Soils

<p> Transparent soils are developed as a physical modelling of macroscopic soil behaviors in geotechnical engineering aspect. Transparent surrogates with its index-matching fluid, called as transparent porous media or transparent soils, have been used for simulating geotechnical properties of natural soils. Visualization technique itself have been applied to microscopic level of soil deformation and soil flow problems such as X-ray, Computerized Tomography (CT), and Magnetic Resonance Imaging (MRI) cameras by very expensive apparatuses with highly operating skills. Geotechnical researches need rather understanding of macroscopic scale of larger test models with inexpensive experimental industrial substances. Transparent soils have been developed to achieve these needs with easy handling performance. <br> The authors demonstrated a pumping test in a glass tank of 30mm width by 80mm length by 70mm height filled with transparent hydrated superabsorbent polymer to represent aquitard (clay layer) over aquifer (saturated silica sand). The subsidence within the synthetic clay layer due to pumping of pore water from silica sand was constantly monitored by target racking method using four 8mm-diameter particles immersed in the synthetic clay layer. The test successfully visualized deformation due to vertical propagation of pore water pressure during subsidence event within the transparent synthetic clay layer. It was also found that this experiment result and the results from three-dimensional numerical simulation of poroelastic deformation were consistent with each other.</p>

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.

Sign in / Sign up

Export Citation Format

Share Document