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

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Computerized Cone Penetration Test for Soil Classification

Transportation Research Record Journal of the Transportation Research Board ◽

10.3141/2053-07 ◽

2008 ◽

Vol 2053 (1) ◽

pp. 47-64 ◽

Cited By ~ 5

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.

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Calibration of a Miniature Cone Penetrometer for Highway Applications

Transportation Research Record Journal of the Transportation Research Board ◽

10.3141/1614-02 ◽

1998 ◽

Vol 1614 (1) ◽

pp. 8-14 ◽

Cited By ~ 4

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.

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

Canadian Geotechnical Journal ◽

10.1139/t09-133 ◽

2010 ◽

Vol 47 (7) ◽

pp. 709-718 ◽

Cited By ~ 32

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).

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Soil classification using the cone penetration test

Canadian Geotechnical Journal ◽

10.1139/t90-014 ◽

1990 ◽

Vol 27 (1) ◽

pp. 151-158 ◽

Cited By ~ 468

Author(s):

P. K. Robertson

Keyword(s):

Case History ◽

Soil Classification ◽

Cone Penetration Test ◽

Deep Borehole ◽

Penetration Test ◽

Cone Penetration ◽

Using Data ◽

New System ◽

Good Agreement

Several charts exist for evaluating soil type from electric cone penetration test (CPT) data. A new system is proposed based on normalized CPT data. The new charts are based on extensive data available from published and unpublished experience worldwide. The new charts are evaluated using data from a 300 m deep borehole with wire-line CPT. Good agreement was obtained between samples and the CPT data using the new normalized charts. Recommendations are provided concerning the location at which to measure pore pressures during cone penetration. Key words: soil classification, cone penetration test, in situ, case history.

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

Global Journal of Engineering and Technology Advances ◽

10.30574/gjeta.2021.9.2.0127 ◽

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.

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

Artificial intelligence for engineering design analysis and manufacturing ◽

10.1017/s0890060420000025 ◽

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.

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Cone Penetration Test Study of Ultra Soft Soil after Vacuum Preloading

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.580-583.585 ◽

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.

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

International Journal of Geo-Engineering ◽

10.1186/s40703-021-00146-3 ◽

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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Using Cone Penetration Test to Determine Drained Friction Angle of Sands

Transportation Research Record Journal of the Transportation Research Board ◽

10.1177/0361198196152600108 ◽

1996 ◽

Vol 1526 (1) ◽

pp. 57-63 ◽

Cited By ~ 1

Author(s):

X. H. Shen Huang ◽

C. H. Juang

Keyword(s):

Case Studies ◽

Model Uncertainty ◽

Friction Angle ◽

Cone Penetration Test ◽

Penetration Test ◽

Cone Penetration ◽

Tip Resistance ◽

Aggregation Technique

Existing relations that are commonly used for determining the drained friction angle (Φ’) of sands using tip resistance (qc) from a cone penetration test are examined. Emphasis is placed on reducing the uncertainty associated with these qc-Φ’ relations. A methodology is developed by which the uncertainty in these relations, called model uncertainty, may be reduced through the use of an aggregation technique based on characterization of sand compressibility. Case studies are presented to illustrate the entire methodology. Results of the case studies show that the uncertainty associated with these qc-Φ’ relations may be reduced and the reliability of the estimated drained friction angle may be improved.

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