Reliability of self-boring pressuremeter in sand

1999 ◽  
Vol 36 (1) ◽  
pp. 102-110
Author(s):  
Debasis Roy ◽  
JMO Hughes ◽  
Richard G (Dick) Campanella
Keyword(s):  
The United States ◽  
The Self ◽  
Western Canada ◽  
Engineering Profession ◽  
Cone Penetration ◽  
Pressuremeter Test ◽  
Cone Tip Resistance ◽  
Tip Resistance ◽  
Testing Tool

The cone penetration test (CPT) is viewed by a majority in the geotechnical engineering profession as a preferred in situ testing tool, while the self-boring pressuremeter test (SBPMT) is sometimes viewed to be of questionable reliability. A comparative statistical study of SBPMT data and CPT cone tip resistance is undertaken in this research to examine whether the test data do actually support the perceived notion. Data from seven sand and silt sites in western Canada and one location in the United States have been examined. The sensitivity of the SBPMT to the variability in the state of packing is quantified and compared with the corresponding values for the cone tip resistance. The results indicate that the sensitivity of cone tip resistance and the SBPMT data to the variability in the in situ state of packing is comparable. Comparison of estimates of procedural uncertainties in the SBPMT and the CPT also leads to a similar conclusion. These observations do not support the notion of a general lack of reliability of the self-boring pressuremeter at sand-silt sites.Key words: reliability, sand, self-boring pressuremeter, piezocone, inherent variability, procedural uncertainty.

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.

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.

Computerized Cone Penetration Test for Soil Classification

2008 ◽  
Vol 2053 (1) ◽  
pp. 47-64 ◽  
Author(s):  
Murad Y. Abu-Farsakh ◽  
Zhongjie Zhang ◽  
Mehmet Tumay ◽  
Mark Morvant
Keyword(s):  
Classification System ◽  
Soil Classification ◽  
Cone Penetration Test ◽  
Classification Systems ◽  
Fuzzy Classification ◽  
Classification Methods ◽  
Penetration Test ◽  
Cone Penetration ◽  
Cone Tip Resistance ◽  
Tip Resistance

Computerized MS-Windows Visual Basic software of a cone penetration test (CPT) for soil classification was developed as part of an extensive effort to facilitate the implementation of CPT technology in many geotechnical engineering applications. Five CPT soil engineering classification systems were implemented as a handy, user-friendly, software tool for geotechnical engineers. In the probabilistic region estimation and fuzzy classification methods, a conformal transformation is first applied to determine the profile of soil classification index (U) with depth from cone tip resistance (qc) and friction ratio (Rf). A statistical correlation was established in the probabilistic region estimation method between the U index and the compositional soil type given by the Unified Soil Classification System. Conversely, the CPT fuzzy classification emphasizes the certainty of soil behavior. The Schmertmann and Douglas and Olsen methods provide soil classification charts based on cone tip resistance and friction ratio. However, Robertson et al. proposed a three-dimensional classification system that is presented in two charts: one chart uses corrected tip resistance (qt) and friction ratio (Rf); the other chart uses qt and pore pressure parameter (Bq) as input data. Five sites in Louisiana were selected for this study. For each site, CPT tests and the corresponding soil boring results were correlated. The soil classification results obtained using the five different CPT soil classification methods were compared.

In situ testing and its application to foundation engineering

1986 ◽  
Vol 23 (4) ◽  
pp. 573-594 ◽  
Author(s):  
P. K. Robertson
Keyword(s):  
Test Methods ◽  
Load Test ◽  
Foundation Engineering ◽  
Penetration Test ◽  
In Situ Testing ◽  
Cone Penetration ◽  
Specific Test ◽  
Pressuremeter Test ◽  
In Situ Test

The status of in situ testing and its application to foundation engineering are presented and discussed. The in situ test methods are discussed within the framework of three groups: logging, specific, and combined test methods. The major logging test methods discussed are standard penetration test (SPT), cone penetration test (CPT), and the flat plate dilatometer test (DMT). The major specific test methods discussed are the prebored pressuremeter test (PMT), the self-bored pressuremeter test (SBPMT), and the screw plate load test (SPLT). Discussion is also presented on recent tests that combine features of logging tests (using the CPT) and specific tests (e.g. the seismic, the electrical resistivity/dielectric, and the lateral stress sensing cone penetration tests). A brief discussion is also presented on the applicability, as perceived by the author, of existing in situ test methods and the future of in situ testing applied to foundation engineering. Key words: in situ testing, foundation engineering, penetration testing, pressuremeter.

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.

Calibration of a Miniature Cone Penetrometer for Highway Applications

1998 ◽  
Vol 1614 (1) ◽  
pp. 8-14 ◽  
Author(s):  
Pradeep U. Kurup ◽  
Mehmet T. Tumay
Keyword(s):  
Ground Improvement ◽  
Cone Penetration Test ◽  
Test System ◽  
Soil Parameters ◽  
Cone Penetrometer ◽  
Penetration Test ◽  
Cone Penetration ◽  
Tip Resistance ◽  
In Situ Investigation

The electronic cone penetrometer is an important in situ investigation tool of choice for site characterization. Application of this proven concept of the cone penetration test (CPT) to highway design and construction control by miniaturization is described. A miniature cone penetrometer with a projected cone area of 2 cm2 has been developed and implemented in a continuous intrusion miniature cone penetration test system (CIMCPT). This device may be used for rapid, accurate, and economical characterization of sites and to determine engineering soil parameters needed in the design of pavements, embankments, and earth structures. The miniature cone penetration test (MCPT) gives finer details than the standard 10-cm2 cross-sectional area reference cone penetrometer. This makes the MCPT attractive for subgrade characterization, quality-control assessment, compaction control of embankments, and assessment of ground improvement effectiveness for transportation infrastructure. In situ calibration of the CIMCPT system was conducted at a highway embankment site in Baton Rouge, Louisiana. MCPT penetration profiles were compared with those obtained by using the standard cone penetrometer at the same site. The tip resistance of the MCPT was 10 percent higher than that of the reference CPT. The sleeve friction and friction ratio of the reference CPT were higher than that of the MCPT by 12 and 23 percent, respectively. Calibration was also performed to determine empirical cone factors required for estimating undrained shear strength from MCPT data.

Further Study on the Application of Self-Boring Pressuremeter Test in Clays

2011 ◽  
Vol 243-249 ◽  
pp. 2752-2758
Author(s):  
Quan Cao ◽  
Hong Chen
Keyword(s):  
Experimental Investigation ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Small Strain ◽  
Linear Analysis ◽  
The Self ◽  
Geotechnical Investigation ◽  
Pressuremeter Test ◽  
In Situ Method

The self-boring pressuremeter test has potential advantages over the conventional in situ method in the geotechnical investigation. It not only provides fundamental soil properties for the designer, but also plays more important role in the geotechnical analysis. With help of Cambridge self-boring model pressuremeter tests, some new application are studied in this paper as following: (1) Analysis of stress paths in clays adjacent to the cavity wall during self-boring pressuremeter test; (2) Experimental investigation on stiffness of soils at small strain under non-linear analysis; and (3) Study on magnitude of the changes in pore-water pressure of clays, which will help to enlarge the application of self-boring pressuremeter test in geotechnical engineering.

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.

Experimental Research on Determining the Geotechnical Parameters with CPTU Methods

2011 ◽  
Vol 250-253 ◽  
pp. 1798-1803
Author(s):  
Yan Yong An ◽  
Bao Tian Wang
Keyword(s):  
Soft Clay ◽  
Cohesive Soil ◽  
Sensor Technology ◽  
Soil Parameters ◽  
Cone Penetration ◽  
Test Technique ◽  
Geotechnical Parameters ◽  
Cone Tip Resistance ◽  
Laboratory Test Results ◽  
Tip Resistance

Cone penetration test is a fast and efficient in-situ test technique. With the development of sensor technology and the use of new probes, such test is employed in more fields and reveals more soil parameters. Based on the advanced CPTU equipment, porewater pressure dissipation processes were measured at different depths, dissipation characteristics of the sandy soil and cohesive soil were analyzed respectively; Then, consolidation and permeability coefficients of the cohesive soil were calculated, the results are close to the laboratory test results. Undrained shear strength of soft clay were determined use theoretical and empirical methods, calculation accuracy of these methods were analyzed and the results show that the total cone tip resistance method is in good consistence with the measured values. CPTU is able to provide plenty of geotechnical parameters; therefore, more experience of regional tests should be drawn so as to produce more economic and technical benefit in the future.

Thin-layer effects on the CPT qc measurement

2005 ◽  
Vol 42 (5) ◽  
pp. 1302-1317 ◽  
Author(s):  
M M Ahmadi ◽  
P K Robertson
Keyword(s):  
Correction Factor ◽  
Soft Clay ◽  
Soil Layer ◽  
Cone Penetration ◽  
Dense Sand ◽  
Layer Interface ◽  
Cone Tip Resistance ◽  
Tip Resistance ◽  
Resistance Modeling ◽  
Good Agreement

A numerical analysis is presented to model the cone penetration test (CPT) tip resistance in layered soil. Analyses are performed for two-layer soils composed of either sands with different relative densities or different materials (sand and clay). Parametric numerical modeling is used to determine the distance that a cone senses a new upcoming soil layer interface or a layer interface behind. Analyses are also carried out for a thin sand layer embedded in soft clay. It is seen that the full tip resistance may not be reached in thin stiff layers. This is especially true for penetration in thin dense sand layers interbedded in softer clay. A correction factor is suggested to correct the cone tip resistance in thin sand layers. The higher the stiffness and the thinner the layer, the larger the correction factor. The numerical results obtained in this paper are in good agreement with experimental observations. Some limitations of a previously proposed correction factor are discussed.Key words: cone tip resistance, modeling, sand, clay, interface influence distance, layering.

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