Numerical Simulation of Cone Penetration Tests Inside Suction Caisson Foundations in Sand

2020 ◽  
Author(s):  
Marc Stapelfeldt ◽  
Diaa Alkateeb ◽  
Jürgen Grabe ◽  
Britta Bienen
Keyword(s):  
Cone Penetration Test ◽  
Service Performance ◽  
Small Scale ◽  
Penetration Test ◽  
Cone Penetration ◽  
Soil Plug ◽  
Suction Caisson ◽  
Cone Penetration Tests ◽  
Caisson Foundations ◽  
Penetration Tests

Abstract Offshore wind is increasingly utilised as a renewable energy source. A growing number of bottom fixed wind turbines installed offshore are supported by suction caisson foundations. The suction-assisted installation remains a source of uncertainty towards the in-service performance due to the unknown post-installation soil plug state. Cone penetration tests within the suction caisson can help to improve the reliability. Therefore, cone penetration tests were employed in centrifuge tests to investigate the plug state in a previously installed suction caisson. However, the performance of a cone penetration test in a small-scale experiment is connected to uncertainties: A relatively large diameter device is required to conduct the cone penetration test — especially in a centrifuge test. Different finite element models are developed in order to visualise and investigate a cone penetration test inside a suction caisson. The numerical analysis results are validated through the back-calculation of centrifuge cone penetration tests. The results of the simulated cone penetration tests inside a suction caisson are evaluated and compared to the centrifuge experiments. This investigation reinforces the scope of the centrifuge experiments and emphasises a considerable effect of the pressure transferral through the caisson lid in the soil plug state. Hence, the results of this study reduce existing uncertainties regarding possible suction installation effects on the in-service performance of caisson foundations.

Numerical Simulation of Cone Penetration Tests Inside Suction Caisson Foundations in Sand

2021 ◽  
Author(s):  
Marc Stapelfeldt ◽  
Diaa Alkateeb ◽  
J\xfcrgen Grabe ◽  
Britta Bienen
Keyword(s):  
Numerical Simulation ◽  
Cone Penetration ◽  
Suction Caisson ◽  
Cone Penetration Tests ◽  
Caisson Foundations ◽  
Penetration Tests

Improvement of GPR Full-waveform inversion images using Cone Penetration Test data

Geophysics ◽  
2021 ◽  
pp. 1-74
Author(s):  
Zhen Zhou ◽  
Anja Klotzsche ◽  
Jessica Schmäck ◽  
Harry Vereecken ◽  
Jan van der Kruk
Keyword(s):  
Waveform Inversion ◽  
Cone Penetration Test ◽  
Small Scale ◽  
Inversion Method ◽  
Full Waveform Inversion ◽  
Penetration Test ◽  
Cone Penetration ◽  
Full Waveform ◽  
Effective Source

Detailed characterization of aquifers is critical and challenging due to the existence of heterogeneous small-scale high-contrast layers. For an improved characterization of subsurface hydrological characteristics, crosshole ground penetrating radar (GPR) and Cone Penetration Test (CPT) measurements are performed. In comparison to the CPT approach that can only provide 1D high resolution data along vertical profiles, crosshole GPR enables measuring 2D cross-sections between two boreholes. Generally, a standard inversion method for GPR data is the ray-based approach that considers only a small amount of information and can therefore only provide limited resolution. In the last decade, full-waveform inversion (FWI) of crosshole GPR data in time domain has matured, and provides inversion results with higher resolution by exploiting the full recorded waveform information. However, the FWI results are limited due to complex underground structures and the non-linear nature of the method. A new approach that uses CPT data in the inversion process is applied to enhance the resolution of the final relative permittivity FWI results by updating the effective source wavelet. The updated effective source wavelet possesses a priori CPT information and a larger bandwidth. Using the same starting models, a synthetic model comparison between the conventional and updated FWI results demonstrates that the updated FWI method provides reliable and more consistent structures. To test the method, five experimental GPR cross-section results are analyzed with the standard FWI and the new proposed updated approach. Both synthetic and experimental results indicate the potential of improving the reconstruction of subsurface aquifer structures by combining conventional 2D FWI results and 1D CPT data.

The Consolidation State of Red Clay Determined by Cone Penetration Test

2013 ◽  
Vol 639-640 ◽  
pp. 652-656
Author(s):  
Zhen Yu Li ◽  
Qing Qing Tian ◽  
Hong Bin Xiao
Keyword(s):  
Laboratory Experiments ◽  
Soil Depth ◽  
Soil Layer ◽  
Cone Penetration Test ◽  
Penetration Test ◽  
Cone Penetration ◽  
Red Clay ◽  
Foundation Soil ◽  
Cone Penetration Tests ◽  
Static Point

It is of significance to determinate the consolidation state of soil for evaluation of deformation and strength of foundation soil. The consolidation state of red clay is determined through laboratory experiments combined with static cone penetration tests. The results show that the law of consolidation history of red clay is opposite to other soils. The static point resistance obtained from cone penetration test decreases linearly with soil depth increasing. The over-consolidate rate of different soil layer gotten by laboratory experiments also decreases linearly with soil depth increasing. The slopes of two linear regress curves are similar. The change of static point resistance can be used to estimate over-consolidate rate of red clay at different depth.

scholarly journals Comparison of California Bearing Ratio (CBR) Value Based on Cone Penetration Test (CPT) and Dynamic Cone Penetrometer (DCP)

2021 ◽  
Vol 4 (2) ◽  
pp. 70
Author(s):  
Reki Arbianto ◽  
Teguh Yuono ◽  
G Gunarso
Keyword(s):  
Soil Layer ◽  
Cone Penetration Test ◽  
California Bearing Ratio ◽  
Small Scale ◽  
Cone Penetrometer ◽  
Penetration Test ◽  
Cone Penetration ◽  
Dynamic Cone Penetrometer ◽  
Heavy Equipment ◽  
Cbr Test

In civil engineering, land is important because as a place for building infrastructure to be built, so that the building infrastructure on it is stable, adequate carrying capacity is needed. The amount of soil bearing capacity can be determined in several ways, including the California Bearing Ratio (CBR) Field Test, Cone Penetration Test (CPT) and Dynamic Cone Penetrometer (DCP). The CBR and DCP tests are often used to determine the level of surface soil density on road structures, while CPT is usually used to determine the hard soil layer on the building structure. However, in certain situations Sondir and DCP data are often used to predict the CBR value, because the test is quite practical and efficient compared to the CBR test. CBR testing requires heavy equipment which in most small-scale projects is not available. In this study, we compared the CBR value based on the data obtained from the Sondir and DCP tests. Data collection was carried out in Surakarta and its surroundings. Based on the test results, the CBR value generated from the DCP test tends to be smaller than that from the CPT test with a ratio of 0.62: 1. This study resulted in the relationship between CBR values from the results of the CPT and DCP tests shown in the following equation: CBR (DCP) % = 0.2552 CBR(CPT) + 2.6306 and CBR (DCP) % = 0.617 CBR(CPT).

scholarly journals Characterization by Cone Penetration Tests of the decalcified Zandvliet Sand (Lillo Formation, North Belgium)

2021 ◽  
Vol 24 (3-4) ◽  
pp. 159-167
Author(s):  
Jef DECKERS ◽  
Jasper VERHAEGEN ◽  
Ilse VERGAUWEN
Keyword(s):  
Chemical Weathering ◽  
Depositional Environment ◽  
Soil Acidity ◽  
The Other ◽  
Penetration Test ◽  
Cone Penetration ◽  
Cone Resistance ◽  
Cone Penetration Tests ◽  
Penetration Tests ◽  
Overlying Strata

The sandy Zandvliet Member represents a particular, decalcified facies in the top of the Pliocene Lillo Formation in northern Belgium. Based on the correlation with nearby boreholes at the type locality of the Zandvliet Member, we were able to characterize this unit on Cone Penetration Tests. Compared to the underlying Merksem Member, the Zandvliet Member generally shows markedly lower cone resistance values. Since besides the decalcification, the Zandvliet Member is lithologically nearly identical to the underlying Merksem Member, the lower cone resistance values in the Zandvliet Member compared to the Merksem Member can only be the result of the decalcification of the Zandvliet Member. Indeed, the partly decalcified top of the Merksem Member also gives similar cone resistance values as the Zandvliet Member. Decalcification of the Eocene Brussel Sand in central Belgium is also known to have resulted in lower cone resistance values. Our Cone Penetration Test interpretations show that the thickness of the Zandvliet Member strongly varies across short distances (>10 m across 1 km). As the Zandvliet Member thickens, the underlying Merksem Member thins and vice versa. This trend is not in line with that of the under- and overlying strata, i.e. intraformational, nor with the depositional environment of these units. The thickness changes of the Zandvliet Member therefore purely reflect changes in depth of the post-depositional decalcification into the original shell-bearing sand (i.e. original Merksem Member). This confirms the existing hypothesis that the Zandvliet Member actually represents the decalcified part of the Merksem Member. The anomalous heavy mineralogy of the Zandvliet Member compared to the other members of the Lillo Formation cannot be readily explained by the acid chemical weathering which caused the decalcification. This may rather be related to a change in the primary heavy mineral signal of the upper part of the Merksem Member and equivalent Zandvliet Member compared to the underlying sequences of the Lillo Formation. The reason for the post-depositional decalcification could be similar to the Pleistocene changes in soil acidity invoked for decalcification of time-equivalent Red Crag sand in England.

Static cone tests and settlement of calcareous desert sands

1986 ◽  
Vol 23 (3) ◽  
pp. 297-303 ◽  
Author(s):  
Nabil F. Ismael ◽  
Abdul Majeed Jeragh
Keyword(s):  
Ground Surface ◽  
Field Tests ◽  
Standard Penetration Test ◽  
Penetration Test ◽  
Cone Penetration ◽  
Soil Pressure ◽  
Cone Penetration Tests ◽  
Below Ground ◽  
Load Tests ◽  
Penetration Tests

The results of a recent in situ testing program to establish standard penetration test – cone penetration test (SPT–CPT) correlation for the windblown calcareous desert sands of Kuwait are presented and analyzed. The program consisted of auger borings and static cone tests at five sites along a 35 km long corridor. The resulting correlation was employed for prediction of the allowable soil pressure of footings at seven sites in Kuwait where load tests were carried out on square concrete footings placed at a depth of 1 m below ground surface. A comparison of the measured to the predicted soil pressures using the Schmertmann method indicated very close agreement. The average ratio of measured to predicted soil pressure is 93% for the seven test sites. Recommendations are made for further testing to determine the long-term settlement components due to creep and cyclic loading. Key words: load tests, sands, footings, allowable pressure, settlement, field tests, borings, cone penetration tests.

Notes on the Correlation of Cone Penetration Test Results in Weak Chalk at Norwich, Norfolk

1986 ◽  
Vol 2 (1) ◽  
pp. 219-221
Author(s):  
H. Erwig ◽  
J. I. Pattinson
Keyword(s):  
Site Investigation ◽  
Standard Penetration Test ◽  
Test Results ◽  
Penetration Test ◽  
Cone Penetration ◽  
Cone Penetration Tests ◽  
Deep Boreholes ◽  
A Site ◽  
Penetration Tests

AbstractA site investigation has been carried out at Norwich, Norfolk consisting of deep boreholes and static electric cone penetration tests. Notes are given on the methods of investigation and on tentative classification of the weak chalk in this area together with the measured parameters of cone end resistance and standard penetration test ‘N’ values.

scholarly journals Testing Grease Consistency

Lubricants ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 14
Author(s):  
Alan Gurt ◽  
Michael M. Khonsari
Keyword(s):  
Yield Stress ◽  
Power Law ◽  
Simple Procedure ◽  
New Method ◽  
Penetration Test ◽  
Cone Penetration ◽  
Cone Penetration Tests ◽  
Relative Consistency ◽  
Penetration Tests

Because of the influential role of consistency in selecting a grease for a given application, accurate and meaningful methodologies for its measurements are vitally important. A new method, recently introduced, uses a rheometer to compress a grease sample to evaluate a relative consistency between a fresh and degraded grease; however, the results of this approach compared to a standard penetrometer and other methods of assessing consistency have not been studied. This paper takes a closer look at the relevant parameters involved in the rheometer penetration test and establishes a recommended procedure for its use. The consistency of various greases is then tested using this method and compared to results obtained from yield stress, crossover stress, and cone penetration tests. The results indicate that rheometer penetration may be used to assess the change in consistency for a given grease but should not be used to compare different greases. For this purpose, the crossover stress method is recommended, which is shown to correlate very well with cone penetration while using a simple procedure and allowing the use of a substantially smaller sample. A strong power law correlation between crossover stress and cone penetration was found for all greases tested and is presented in Figure 12.

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