Evaluation of soil state from SBP and CPT: A case history

2008 ◽  
Vol 45 (6) ◽  
pp. 824-844 ◽  
Author(s):  
Mohsen Ghafghazi ◽  
Dawn A. Shuttle
Keyword(s):  
Case History ◽  
Large Strain ◽  
State Parameter ◽  
Ground Truth ◽  
Cohesionless Soils ◽  
Pressuremeter Test ◽  
Hydraulic Fill ◽  
Strength Data ◽  
Accuracy Validation

The cone pressuremeter test (CPT) is widely used to determine the in situ “state” of cohesionless soils. However, although the CPT is simple, inexpensive, and accurate the subsequent interpretation contains substantial uncertainties even with modern approaches. Self-bored pressuremeters (SBP) have the opposite attributes. Obtaining good SBP data is difficult in sands, but the subsequent evaluation can be rather precise. This paper compares estimates of the in situ state parameter, ψ, from CPT and SBP tests carried out in a uniform hydraulic fill. This case history is unusual in that (i) the fill was well controlled and uniform, (ii) comprehensive laboratory strength data exists, (iii) the CPT was calibrated for the fill in a large chamber, and (iv) good SBP data exist. These SBP and CPT tests are independently analyzed using a calibrated critical state model implemented in a large strain finite element code. The effects of ageing and fabric are considered. The resulting most probable in situ state parameters for the fill from the CPT are close to those derived from the SBP. Although not proof of accuracy (validation) of either test, since ground truth is not known, the results lend support to the adequacy of the interpretation methodology used for both. Further improvements are discussed.

Shear wave velocity to evaluate in situ state of cohesionless soils

1995 ◽  
Vol 32 (5) ◽  
pp. 848-858 ◽  
Author(s):  
J.C. Cunning ◽  
P.K. Robertson ◽  
D.C. Sego
Keyword(s):  
Shear Wave ◽  
Wave Velocity ◽  
Effective Stress ◽  
Shear Wave Velocity ◽  
Critical State ◽  
State Parameter ◽  
Worked Examples ◽  
Shear Loading ◽  
Cohesionless Soils

Shear wave velocity (Vs) measurements were carried out in a triaxial testing program on three different cohesionless soils. The Vs was measured using bender elements during consolidation and at ultimate steady state. After consolidation the soil samples were loaded in shear under constant strain rate triaxial compression either drained or undrained to determine their ultimate steady or critical state (USS) at large strains. The Vs measurements were used to develop relationships between the void ratio (e), mean normal effective stress (p′), and Vs. The shear loading results were expressed within the framework of critical state soil mechanics. The results of the Vs and USS information were combined with the state parameter concept to develop an equation to use field measured Vs to estimate the in situ consolidation state within a soil. Thus, the contractive–dilative boundary with respect to vertical effective stress for large strain loading can be determined from in situ measurements of Vs. These can then be used as a design aid to determine if a soil deposit is potentially susceptible to flow liquefaction. Worked examples to illustrate the procedure are given. Key words : shear wave velocity, cohesionless soil, in situ state, state parameter, liquefaction, laboratory testing.

scholarly journals Characterization of unsaturated mine waste: a case history

2017 ◽  
Vol 54 (12) ◽  
pp. 1752-1761 ◽  
Author(s):  
P.K. Robertson ◽  
A. Viana da Fonseca ◽  
B. Ulrich ◽  
J. Coffin
Keyword(s):  
Shear Wave ◽  
Wave Velocity ◽  
Shear Wave Velocity ◽  
Case History ◽  
Seismic Velocity ◽  
Large Strain ◽  
Mine Waste ◽  
Beneficial Effects

It is becoming increasingly common in the mining industry for either crushed ore or filtered mine waste to be stacked to a significant height (>100 m) in a moist state with little compaction, resulting in deposits that can be potentially loose and unsaturated. This paper presents a case history describing the characterization of stacked filtered tailings at a mine site in South America. Cone penetration tests with pore pressure and seismic velocity measurements (SCPTu) were carried out along with selected drilling, sampling, and laboratory testing. Compression wave velocity (Vp) and shear wave velocity (Vs) profiles were obtained and compared with laboratory values on reconstituted saturated and unsaturated samples. Results indicate that shear wave velocity is sensitive to suction hardening effects and appears to capture the correct unsaturated in situ behavior. The cone resistance, which is a large strain measurement, can destroy the beneficial effects of suction hardening and appears to be insensitive to the unsaturated in situ behavior, but may capture the correct behavior after the beneficial effects of suction are removed if the soil becomes saturated.

scholarly journals Reference Measurements in Developing UAV Systems for Detecting Pests, Weeds, and Diseases

2021 ◽  
Vol 13 (7) ◽  
pp. 1238
Author(s):  
Jere Kaivosoja ◽  
Juho Hautsalo ◽  
Jaakko Heikkinen ◽  
Lea Hiltunen ◽  
Pentti Ruuttunen ◽  
...  
Keyword(s):  
Reference Data ◽  
Measurement Techniques ◽  
Synthetic Data ◽  
Ground Truth ◽  
Precision Farming ◽  
Aerial Imaging ◽  
Aerial Vehicle ◽  
Uav Images ◽  
Reference Measurements

The development of UAV (unmanned aerial vehicle) imaging technologies for precision farming applications is rapid, and new studies are published frequently. In cases where measurements are based on aerial imaging, there is the need to have ground truth or reference data in order to develop reliable applications. However, in several precision farming use cases such as pests, weeds, and diseases detection, the reference data can be subjective or relatively difficult to capture. Furthermore, the collection of reference data is usually laborious and time consuming. It also appears that it is difficult to develop generalisable solutions for these areas. This review studies previous research related to pests, weeds, and diseases detection and mapping using UAV imaging in the precision farming context, underpinning the applied reference measurement techniques. The majority of the reviewed studies utilised subjective visual observations of UAV images, and only a few applied in situ measurements. The conclusion of the review is that there is a lack of quantitative and repeatable reference data measurement solutions in the areas of mapping pests, weeds, and diseases. In addition, the results that the studies present should be reflected in the applied references. An option in the future approach could be the use of synthetic data as reference.

scholarly journals Analyzing Satellite Ocean Color Match-Up Protocols Using the Satellite Validation Navy Tool (SAVANT) at MOBY and Two AERONET-OC Sites

2021 ◽  
Vol 13 (14) ◽  
pp. 2673
Author(s):  
Adam Lawson ◽  
Jennifer Bowers ◽  
Sherwin Ladner ◽  
Richard Crout ◽  
Christopher Wood ◽  
...  
Keyword(s):  
Infrared Imaging ◽  
Ocean Color ◽  
Visible Spectrum ◽  
Ground Truth ◽  
Naval Research ◽  
Satellite Validation ◽  
The Difference ◽  
Stability And Accuracy ◽  
Satellite Ocean Color

The satellite validation navy tool (SAVANT) was developed by the Naval Research Laboratory to help facilitate the assessment of the stability and accuracy of ocean color satellites, using numerous ground truth (in situ) platforms around the globe and support methods for match-up protocols. The effects of varying spatial constraints with permissive and strict protocols on match-up uncertainty are evaluated, in an attempt to establish an optimal satellite ocean color calibration and validation (cal/val) match-up protocol. This allows users to evaluate the accuracy of ocean color sensors compared to specific ground truth sites that provide continuous data. Various match-up constraints may be adjusted, allowing for varied evaluations of their effects on match-up data. The results include the following: (a) the difference between aerosol robotic network ocean color (AERONET-OC) and marine optical Buoy (MOBY) evaluations; (b) the differences across the visible spectrum for various water types; (c) spatial differences and the size of satellite area chosen for comparison; and (d) temporal differences in optically complex water. The match-up uncertainty analysis was performed using Suomi National Polar-orbiting Partnership (SNPP) Visible Infrared Imaging Radiometer Suite (VIIRS) SNPP data at the AERONET-OC sites and the MOBY site. It was found that the more permissive constraint sets allow for a higher number of match-ups and a more comprehensive representation of the conditions, while the restrictive constraints provide better statistical match-ups between in situ and satellite sensors.

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.

Water Shut-Off Using an Inflatable Composite Sleeve Polymerised In-Situ. A Case History on Forties Delta

1998 ◽  
Author(s):  
J. Leighton ◽  
J.L. Saltel ◽  
J. Morrison ◽  
R. Welch ◽  
J. Pilla
Keyword(s):  
Case History

Investigation of Small- to Large-Strain Moduli Correlations of Rockfill Materials – Application to Romaine-2 Dam

2021 ◽  
Author(s):  
Ibrahim Lashin ◽  
Michael Ghali ◽  
Marc Smith ◽  
Daniel Verret ◽  
Mourad Karray
Keyword(s):  
Large Strain ◽  
Deformation Behaviour ◽  
Numerical Data ◽  
Small Strain ◽  
Hyperbolic Model ◽  
Large Strains ◽  
Initial Modulus ◽  
Rockfill Materials ◽  
Materials Used

Establishment of a relationship between the shear wave velocity (Vs) and other geotechnical parameters of rockfill soils at large strains (oedometer modulus, Moedo, tangent modulus, Et) is considered a significant step towards more precise modelling of earth-structure deformation behaviour. In this study, four samples of different gradations, reconstituted from the rockfill materials used in the construction of the Romaine-2 dam, were experimented to correlate the small strain to large strain moduli. Development of Moedo and Vs with consolidation was measured in the laboratory using the piezoelectric ring-actuator technique (P-RAT) incorporated in a large oedometer. Therefore, a correlation between Moedo and small strain shear modulus Go was proposed. Moreover, numerical simulations were performed based on the Duncan-Chang hyperbolic model to correlate the Vs to Duncan-Chang initial modulus(Ei). Based on the experimental and numerical data, a relation between Ei and Vs of the tested rockfill has been established. Verification studies were also carried out on in-situ measurements during Romaine-2 dam construction, proofing the ability of the proposed relationships to predict Ei related to the minor principal stress (σ3) from in-situ Vs measurement. The proposed correlations could help the geotechnical designers to estimate accurately the deformation of rockfill materials from in-situ Vs measurement.

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