Observations on the development of pore-water stresses during piezocone penetration in clays

1990 ◽  
Vol 27 (4) ◽  
pp. 418-428 ◽  
Author(s):  
Paul W. Mayne ◽  
Fred H. Kulhawy ◽  
J. Neil Kay
Keyword(s):  
Water Stress ◽  
Pore Water ◽  
Field Tests ◽  
In Situ Tests ◽  
Stress Effects ◽  
Cone Tip Resistance ◽  
Clay Deposits ◽  
Tip Resistance ◽  
Porous Element ◽  
Penetration Tests

Piezocone data from 83 clay sites are reviewed to investigate first-order trends between measured penetration pore-water stresses (ut and ubt) and corrected cone-tip resistance (qT). It is shown that the presence of fissures in clay deposits and of fissured crusts significantly affects the pore water stress response. Commercially available piezocones primarily favor the location of the porous element either (1) on the cone tip or face (ut) or (2) just behind the tip (ubt). The former (ut) provides optimal profiling while the latter (ubt) is required for correcting measured cone-tip resistances for pore-water stress effects acting on unequal areas of the cone. The available data indicate that qT predominantly reflects penetration pore-water stresses (ut) with measured ratios of ut/qT on the cone face averaging in the order of 0.73 for most intact clays, 0.64 specifically for Leda clays, and 0.46 for fissured clays. Behind the cone tip, the ratio of ubt/qT averages about 0.53 for intact clays, 0.58 specifically for Leda clays, and near zero or slightly negative for heavily overconsolidated fissured clays. Key words: clays, cone penetrometers, field tests, fissuring, in situ tests, penetration tests, piezocones, pore-water stresses.

Comparison of Measured and Back Estimated Cone Penetration Resistance of Sand

2008 ◽  
Author(s):  
Meen-Wah Gui ◽  
Dong-Sheng Jeng
Keyword(s):  
Penetration Resistance ◽  
Cavity Expansion ◽  
Cone Penetration ◽  
Cone Penetration Tests ◽  
Cone Tip Resistance ◽  
Tip Resistance ◽  
Cone Penetration Resistance ◽  
Expansion Theory ◽  
Cavity Expansion Theory ◽  
Penetration Tests

The application of cavity expansion theory in the back estimation of cone penetration tests conducted in calibration chambers has been carried out by many researchers. However, the theory is seldom employed by centrifuge modelers. Based on the work of spherical cavity expansion of previous researchers, this study proposed an analytical solution that incorporates the effects of cone geometry and surface roughness and the effect of compressibility to estimate the cone tip resistance. The calculated results are compared with the measured cone penetration resistance of four cone penetration tests performed in the centrifuge. The cone penetration tests were conducted in granular soil specimens having relative densities ranging between 54% and 89%. The comparison demonstrates the capacity of the cavity expansion theory in the prediction of the centrifuge cone penetration resistance.

Influence of placement method on the cone penetration resistance of hydraulically placed sand fills

2001 ◽  
Vol 38 (3) ◽  
pp. 592-607 ◽  
Author(s):  
K M Lee
Keyword(s):  
Cone Penetration ◽  
Density Profiles ◽  
Hydraulic Fill ◽  
Dense Sand ◽  
Cone Penetration Tests ◽  
Cone Tip Resistance ◽  
Tip Resistance ◽  
Wide Range ◽  
Penetration Tests

The reclamation for the new airport at Chek Lap Kok in Hong Kong included the placement of a substantial volume of sand fill by various hydraulic placement techniques, which resulted in a wide range of as-placed densities of the sand fill. This paper described the use of cone penetration tests (CPT) on the evaluation of the possible ranges of density achievable by various hydraulic placement methods adopted in the construction of the new airport. The results of the CPT indicated that the placement technique is one of the most important factors in controlling the as-placed density of hydraulically placed sand fill. There is a marked contrast in cone tip resistance (and the associated relative density) profiles for the sand fills formed by subaerial and subaqueous placement methods, in which the cone tip resistance of the sand fill formed by subaerial placement is substantially higher than that of the sand fill formed by subaequeous placement. The results confirm that dense sand fill cannot be formed by subaqueous placement methods. The weakest zone is generally located just beneath the water level where fill is placed by subaqueous discharge.Key words: sand, hydraulic fill, cone penetration test, calibration chamber test, in situ density.

Statistical relationships between piezocone measurements and stress history of clays

1996 ◽  
Vol 33 (3) ◽  
pp. 488-498 ◽  
Author(s):  
B SY Chen ◽  
P W Mayne
Keyword(s):  
Cone Penetration ◽  
Stress History ◽  
Statistical Correlations ◽  
Cone Tip Resistance ◽  
Clay Deposits ◽  
Preconsolidation Pressure ◽  
Tip Resistance ◽  
History Of ◽  
Statistical Relationships ◽  
Oedometer Tests

A database containing piezocone soundings from 205 clay sites around the world has been compiled for the calibration of an analytical cone penetration model and the development of statistical correlations. Yield stresses from laboratory oedometer tests were used as reference values for determining the stress history of natural clay deposits. Both simple and multiple regression analyses were performed on these data to evaluate correlative trends. Several simplified empirical relationships were identified for use in practice with the most reliable in relating preconsolidation stress to net cone tip resistance. Key words: cone tip resistance, overconsolidation ratio (OCR), preconsolidation pressure, piezocone, statistical relationships, stress history.

scholarly journals THE RESULTS OF CORELATION BETWEEN CONE TIP RESISTANCE, PUSH-IN PRESSURE LOAD CELLS AND A COMPRESSION DEVICE / KŪGINIO STIPRIO IR GILIOJO SPRAUSTINIO PAMATO PAGRINDO LAIKOMOSIOS GALIOS BANDYMU, TAIP PAT KITAIS METODAIS NUSTATYTŲ DEFORMACIJŲ MODULIŲ PRIKLAU

2013 ◽  
Vol 5 (5) ◽  
pp. 525-529 ◽  
Author(s):  
Tautvydas Statkus ◽  
Vaidas Martinkus
Keyword(s):  
Field Tests ◽  
Cohesionless Soil ◽  
Soil Deformation ◽  
Regression Analyses ◽  
Deep Foundation ◽  
Compression Device ◽  
Cone Tip Resistance ◽  
Tip Resistance ◽  
Load Cells ◽  
Properties Of Soil

The article is aimed at identifying the correlation between soilcone resistance and soil deformation modules determined referringto the results of tested data on deep foundation bearingcapacity, the push-in pressure cell and the use of an oedometer.Physical and mechanical properties of soil have been determinedconducting laboratory and field tests. After regression analyses,the correlation between cone resistance and different kinds ofsoil deformation modules have been given. The results of theexperimental study can be used for predicting a practical approachto deep foundation in cohesionless soil. Santrauka Šio straipsnio tikslas yra nustatyti priklausomybes tarp grunto kūginio stiprio ir grunto deformacijų modulių, gautų iš giliojo pamato pagrindo laikomosios galios bandymų duomenų, taip pat grunto tyrimo įspraudžiamaisiais horizontaliojo slėgio matuokliais bei kompresiniu aparatu. Straipsnyje pateiktos tiriamojo orasausio smėlinio grunto fizinės ir mechaninės savybės nustatytos laboratoriniais ir lauko tyrimo metodais. Atlikus regresinę bandymų duomenų analizę straipsnio išvadose pateiktos minėtų dydžių priklausomybės. Tyrimo duomenys gali būti panaudoti sudarant praktinį metodą giliųjų spraustinių pamatų smėlinių pagrindų nuosėdžiams prognozuoti.

Detection of smear zone using micro-cone and electrical resistance probe

2009 ◽  
Vol 46 (6) ◽  
pp. 719-726 ◽  
Author(s):  
Dong-Hyun Shin ◽  
Changho Lee ◽  
Jong-Sub Lee ◽  
Woojin Lee
Keyword(s):  
Electrical Resistivity ◽  
Electrical Resistance ◽  
Large Scale ◽  
Outer Boundary ◽  
Soil Disturbance ◽  
Cone Penetrometer ◽  
Cone Tip Resistance ◽  
Tip Resistance ◽  
Prefabricated Vertical Drain ◽  
Penetration Tests

The installation of a prefabricated vertical drain (PVD) using a mandrel results in soil disturbance adjacent to the PVD, which is known as the smear zone. The smear zone is investigated by a series of radial penetration tests including a micro-cone penetrometer and an electrical resistance probe in the clay specimen prepared in a large-scale chamber. The 5 mm diameter micro-cone penetrometer and the 2.1 mm diameter electrical resistance probe produce continuous soil strength and electrical resistivity profiles around the PVD. Almost-constant values of the cone tip resistance and electrical resistivity are measured within the undisturbed zone. The outer boundary of the smear zone is clearly defined by the locations where the deviations of the measured cone tip resistance and electrical resistivity from the constant values are observed. Significant changes in both measurements are observed in the smear zone with remarkably consistent patterns. The smear zone induced by the PVD installation using a rectangular mandrel has an elliptical shape and extends to approximately 3.2∼3.4 times the half-length of the mandrel and 5.3∼5.4 times the half-width of the mandrel.

Analysis of Soil Liquefaction Potential through Three Field Tests-Based Methods: A Case Study of Babol City

2021 ◽  
Vol 13 (4) ◽  
Author(s):  
Ali Hasanzadeh ◽  
◽  
Sadegh Rezaei ◽  
Issa Shooshpasha ◽  
Yasser Ebrahimian Ghajary ◽  
...  
Keyword(s):  
Field Tests ◽  
Earthquake Hazard ◽  
Soil Liquefaction ◽  
Unit Weight ◽  
Liquefaction Potential ◽  
Ground Failure ◽  
Cone Tip Resistance ◽  
Tip Resistance ◽  
Seismic Area ◽  
Liquefaction Assessment

During earthquakes, ground failure is commonly caused by liquefaction. Thus, assessment of soil liquefaction potential in earthquake-prone regions is a crucial step towards reducing earthquake hazard. Since Babol city in Iran country is located in a high seismic area, estimation of soil liquefaction potential is of great importance in this city. For this purpose, in the present research, using field-based methods and geotechnical data (such as unit weight of soil, relative density, SPT number, shear wave velocity and cone tip resistance) of 60 available boreholes in Babol, three liquefaction maps were provided. Finally, one comprehensive liquefaction map was presented for soil of Babol city. The obtained results in this paper are well in line with the previous investigations. Based on the results, the factor of safety in 45% of the study area is less than one (liquefaction occurrence). In addition, the results indicate that since each field-based method requires particular data, applying various field tests is necessary for a more accurate liquefaction assessment.

Effect of Stress History and Shallow Embedment on Centrifuge Cone Penetration Tests in Sand

2019 ◽  
Author(s):  
Anamitra Roy ◽  
Shiaohuey Chow ◽  
Conleth O’Loughlin ◽  
Mark Randolph
Keyword(s):  
Silica Sand ◽  
Cone Penetration ◽  
Stress History ◽  
Buried Structures ◽  
Overconsolidation Ratio ◽  
Cone Penetration Tests ◽  
Cone Tip Resistance ◽  
Tip Resistance ◽  
Order Of Magnitude ◽  
Penetration Tests

Abstract The paper investigates the effect of stress history and shallow embedment on centrifuge cone penetration tests in sand. A series of centrifuge cone penetration tests were performed in loose and dense silica sand at g-levels ranging between 20 and 100 with corresponding overconsolidation ratio (OCR) between 1 and 5. Based on the measured cone tip resistance (qc) profiles, improved empirical correlations have been proposed with depth factors (fD) to impart additional flexibility in accurately back predicting sand relative density (RD) at shallow embedment in normally consolidated (NC) sands. The qc - RD correlations are then extended to capture overconsolidation effects in cone tip resistance, which is broadly consistent with the changes in compressibility and in-situ lateral stresses taking place in sands with increasing OCR levels. The proposed expressions allow accurate quantification of depth corrected CPT profiles in soils of varying overconsolidation ratio, for application in the interpretation of model tests on shallow foundations and anchors and in shallowly buried structures such as pipelines. The expressions also have application for interpretation of field CPT profiles where the thickness of interbedded layers is of similar order of magnitude to the cone diameter.

Glyphosate and Water-Stress Effects on Fruiting and Carbohydrates in Glyphosate-Resistant Cotton

Crop Science ◽  
2003 ◽  
Vol 43 (3) ◽  
pp. 879 ◽  
Author(s):  
Wendy A. Pline ◽  
Randy Wells ◽  
Gary Little ◽  
Keith L. Edmisten ◽  
John W. Wilcut
Keyword(s):  
Water Stress ◽  
Stress Effects

Extending the "Degree Day" Concept of Plant Phenological Development to Include Water Stress Effects

Ecology ◽  
1978 ◽  
Vol 59 (3) ◽  
pp. 431-433 ◽  
Author(s):  
Sherwood B. Idso ◽  
Ray D. Jackson ◽  
Robert J. Reginato
Keyword(s):  
Water Stress ◽  
Stress Effects ◽  
Degree Day

Evaluation on Features of Soft Foundation Engineering and Bearing Layer of Pile in Jiaxing City

2011 ◽  
Vol 90-93 ◽  
pp. 217-221
Author(s):  
Jin Long Zhou ◽  
Qiao Li ◽  
Wei Zhong Cai
Keyword(s):  
Soil Mass ◽  
Shallow Foundation ◽  
Silty Clay ◽  
Foundation Engineering ◽  
Foundation Soil ◽  
Cone Tip Resistance ◽  
Soft Foundation ◽  
Tip Resistance ◽  
Bearing Layer

Through the investigation into composition of major shallow foundation soil mass and the correlation of mechanical indicators in this study, the regression equation of mechanical indicators of the features of local foundation soil mass and the data of in situ testing was obtained. Based on massive quantities of exploration materials, this study analyzed engineering features, distribution status, and the feasibility of silty clay to be used as the bearing layer of the pile in Layer ④2 . The analytical results showed that the silty clay with the uniform depth of over 3.5m and the cone tip resistance in static sounding of over 400MPa could be used as bearing layer of the pile. This study could provide the reference for the accurate understanding of the engineering features of soil mass, and the design and evaluation of foundation in Jiaxing City.

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