Cone Penetration Test Study of Ultra Soft Soil after Vacuum Preloading

2014 ◽  
Vol 580-583 ◽  
pp. 585-588
Author(s):  
Jiong Qi Yu ◽  
Hong Wen Li ◽  
Wen Shuang Wang
Keyword(s):  
Surface Layer ◽  
Soft Soil ◽  
Research Work ◽  
Cone Penetration Test ◽  
Penetration Test ◽  
Cone Penetration ◽  
Vacuum Preloading ◽  
Hydraulic Fill ◽  
Cone Tip Resistance ◽  
Tip Resistance

No sand cushion vacuum preloading method is one of the construction technology for treating the ultra soft soil formed with hydraulic fill at present. The practice is ahead of the scientific research work, as the effect detection technology of the surface-layer improvement is still in the stage of exploration. In this paper, the cone penetration test (CPT) is used to detect the effect of the surface-layer improvement of the ultra soft soil based on one case in Zhejiang province in China. The result shows that the cone tip resistance is at the range of 0.08 ~ 0.40MPa and the thickness varies about 1.5 to 2.2 m of the treated ultra soft soil. The cone tip resistance along the depth has two kinds of curve shape and four zones.

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.

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.

scholarly journals Characterization of Norwegian marine clays with combined shear wave velocity and piezocone cone penetration test (CPTU) data

2010 ◽  
Vol 47 (7) ◽  
pp. 709-718 ◽  
Author(s):  
Michael Long ◽  
Shane Donohue
Keyword(s):  
Shear Wave ◽  
Wave Velocity ◽  
Shear Wave Velocity ◽  
Small Strain ◽  
Cone Penetration Test ◽  
Research Quality ◽  
Penetration Test ◽  
Cone Penetration ◽  
Tip Resistance ◽  
Marine Clays

A database of research-quality piezocone cone penetration test (CPTU) and shear wave velocity, Vs, information for Norwegian marine clays has been assembled to study the small-strain stiffness relationships for these materials and to examine the potential use of CPTU and Vs data in combination for the purposes of characterizing these soils. Data for sites where high-quality block sampling was carried out have mostly been used. Improvements have been suggested to existing correlations between the small-strain shear modulus, Gmax, or Vs and index properties for these soils. Recent research has shown that CPTU corrected cone tip resistance, qt, and especially the pore pressure measured during CPTUs, u2, and Vs can be measured reliably and repeatably and are not operator or equipment dependant. Therefore, a new soil classification chart involving the normalized cone resistance, Qt, and normalized shear wave velocity, Vs1, or Vs1 and Δu/[Formula: see text] (where u is the pore-water pressure and [Formula: see text] is the in situ vertical effective stress) is presented. Using this chart it is possible to clearly distinguish between clays of different overconsolidation ratios (OCRs).

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.

Detection of shear zones in a natural clay slope using the cone penetration test and continuous dynamic sampling

2000 ◽  
Vol 37 (3) ◽  
pp. 652-661 ◽  
Author(s):  
Mahmoud Mahmoud ◽  
David Woeller ◽  
Peter K Robertson
Keyword(s):  
Case History ◽  
Shear Zones ◽  
Cone Penetration Test ◽  
Slope Instability ◽  
Clay Soils ◽  
Penetration Test ◽  
Cone Penetration ◽  
Tip Resistance ◽  
Continuous Dynamic ◽  
Dynamic Sampling

The detection of shear zones along which a mass of soil is moving is essential for understanding the state of stability of natural slopes. Weaker zones in clay soils can be identified from low values of cone penetration test (CPT) tip resistance measured during penetration. This paper presents a case history illustrating the identification of softened shear zones in clay soils using the CPT and the observation of shear surfaces using continuous dynamic sampling (CDS). The analysis and interpretation of the CPT data are discussed in relation to the detection of shear surfaces using the CDS at a site with a history of slope instability. Difficulties encountered in identifying shear zones and detecting shear surfaces are discussed.Key words: cone penetration testing, slope stability, in situ testing, case history, shear zone.

Influence of placement method on the in situ density of hydraulic sand fills

1989 ◽  
Vol 26 (3) ◽  
pp. 453-466 ◽  
Author(s):  
J. A. Sladen ◽  
K. J. Hewitt
Keyword(s):  
Key Words ◽  
Cone Penetration Test ◽  
Penetration Test ◽  
Cone Penetration ◽  
Hydraulic Fill ◽  
Factors Affecting ◽  
Placement Method ◽  
Method Of Placement ◽  
Hydraulic Fills

The range of densities achievable by hydraulic placement of sand straddles the boundary between values giving acceptable potential performance and those giving unacceptable potential performance. This has led to concerns over the safety of structures using hydraulic fills, such as the artificial drilling islands in the Canadian Beaufort Sea. Liquefaction failures of hydraulically placed sand have occurred at four or more of these islands. Until recently, the factors affecting in situ density were little understood. Data obtained from several artificial islands are presented and these are used to demonstrate the overwhelming influence of method of placement on in situ density. The possible reasons for this influence and the implications for design are discussed. Recommendations are made for research that, together with conclusions drawn in the paper, should allow hydraulic fills to be used with more confidence in the future. Key words: sand, hydraulic fill, liquefaction, cone penetration test.

scholarly journals Estimating an empirical equation connecting subgrade reaction modulus with cone penetration test for sandy soils

2021 ◽  
Vol 9 (2) ◽  
pp. 001-008
Author(s):  
Abdelaziz Ahmed Bohagr ◽  
Ghassan Ahmed El gehani ◽  
Mohammed Mahmoud Boudejaja ◽  
Mustafa M Amami
Keyword(s):  
Sandy Soils ◽  
Cone Penetration Test ◽  
Shape Effect ◽  
Subgrade Reaction ◽  
Penetration Test ◽  
Cone Penetration ◽  
Loading Test ◽  
Reaction Coefficient ◽  
Tip Resistance ◽  
Load Tests

In geotechnical engineering, the coefficient of subgrade reaction is regarded as one of the most important parameters used for describing the interaction of soil and structure as well as describing some soil characteristics, subgrade reaction coefficient can be calculated theoretically using many different formulas, laboratory via specific well-known tests, and in site through field plate loading test. On the other hand, the cone penetration test is one of the most frequently used field tests to investigate the soil. The lately carried out researches showed a good relation between the subgrade coefficient and the tip resistance collected from the CPT, but the results obtained from the proposed method are still doubtable. In this paper, fifteen plate load tests and thirty CPTs, already collected for private site investigation project, have been used for finding the best fit equation connecting the subgrade reaction coefficient Ks with the tip resistance qc. The finds of the established equation have been compared extensively with those of other well-known related equations. The results show the ability of the concluded equation to get Ks results in the acceptable range of sandy soils. However, the depth and shape effect on the suggested formula need further investigations since all the plate load tests in this project have been carried out on the soil surface with a 45 cm diameter circular plate.

Developing a new hybrid soft computing technique in predicting ultimate pile bearing capacity using cone penetration test data

2020 ◽  
Vol 34 (1) ◽  
pp. 114-126
Author(s):  
Hooman Harandizadeh
Keyword(s):  
Bearing Capacity ◽  
Frictional Resistance ◽  
Cone Penetration Test ◽  
Group Method ◽  
Data Series ◽  
Penetration Test ◽  
Cone Penetration ◽  
Inference System ◽  
Computing Technique ◽  
Tip Resistance

AbstractThis research intends to investigate a new hybrid artificial intelligence (AI) technique compared to some common CPT methods in estimating axial ultimate pile bearing capacity (UPBC) using cone penetration test (CPT) data in geotechnical engineering applications. A data series of 108 samples was collected in order to develop a new hybrid structure of an adaptive neuro-fuzzy inference system (ANFIS) network, and the group method of the data handling (GMDH) type neural network was optimized by applying the particle swarm optimization (PSO) algorithm over the hybrid ANFIS-GMDH topology, which leads to a new hybrid AI model called as ANFIS-GMDH-PSO. The derived database provides information related to pile load tests, in situ field CPT data, and soil–pile information for introducing the proposed hybrid neural system. The cross-section of the pile toe, average cone tip resistance along embedded pile length, and sleeve frictional resistance along the shaft had been considered as input parameters for the proposed network. The results of this research indicated that the proposed ANFIS-GMDH-PSO model predicted the UPBC with an acceptable precision compared to various CPT methods, including Schmertmann, De Kuiter & Bringen, and LPC/LPCT methods. Moreover, ANFIS-GMDH-PSO network model performance was compared to CPT-based models in terms of statistical criteria in order to achieve a best fitted model. From the statistical results, it was found that the developed ANFIS-GMDH-PSO model has achieved a higher accuracy level in terms of statistical indices compared to CPT-based empirical methods, such as Schmertmann model, De Kuiter & Beringen model, and Bustamante & Gianeselli for predicting driven pile ultimate bearing capacity.

scholarly journals Influence of surcharge on cone penetration test results and the inspection of various approaches for capturing its effect: a case study

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Houman Soleimani Fard ◽  
Meisam Goudarzy
Keyword(s):  
Land Development ◽  
Cone Penetration Test ◽  
Development Project ◽  
Normalization Method ◽  
Sudden Increase ◽  
Penetration Test ◽  
Cone Penetration ◽  
Tip Resistance ◽  
Before And After ◽  
Stress Ratios

AbstractStudies in recent decades demonstrate the significant effect of stress configuration (e.g., vertical stress and lateral confinement) on the shear strength or, in this study, the cone penetration test (CPT) results. Addition of a surcharge over the ground changes the stress condition, and consequently, the CPT tip resistance. In this study, the results of different CPTs conducted before and after backfilling with various thicknesses in a land development project were reviewed while focusing on the trend of an increase in CPT penetration resistance due to the additional surcharge. Both pre- to post-fill stress ratios and soil type affect the rise in corrected $${q}_{c}$$ q c values after backfilling. Moreover, there has always been a sudden increase in $${q}_{c}$$ q c values around the pre-fill surface in all studied cases. In this study, another approach was derived from the reanalysis of CPT data from a specific site for predicting the post-fill corrected $${q}_{c}$$ q c from pre-fill results by considering the above-mentioned factor. Likewise, post-fill results were predicted by depth-normalized pre-fill CPT results using Robertson’s normalization method. The proposed approach in this study showed a better match with the site data compared to the normalization method, especially at and around the pre-fill surface.

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