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Although the cone penetration test (CPT) and flat-plat dilatometer test (DMT) have been used for over 30 years, relatively little has been published regarding comprehensive correlations between the two in situ tests. This paper presents preliminary correlations between the main parameters of the CPT and DMT. The key to the proposed correlations is...
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This paper discusses the development of a framework for classifying soil using normalized piezocone test (CPTU) data from the corrected tip resistance (q(t)) and penetration pore-water pressure at the shoulder (u(2)). Parametric studies for normalized cone tip resistance (Q=q(cnet)/sigma(v0)') and normalized excess pressures (Delta u(2)/sigma(v0)')...
The Cooper Marl is a fine-grained soil which displays a high degree of cementation. Due to its calcareous nature, a high mechanical resistance and high porewater pressure response are measured during cone penetration testing. If soil classification is performed using CPT and CPTU (piezocone) testing, results are not unequivocal. The paper provides...
Although most soil classification charts based on piezocone penetration tests (CPTu) use only two channels of data or paired sets of variables, experience show that soil classification can generally be made more reliable using all three channels of CPTu data (i.e., tip resistance, sleeve friction, and porewater pressure). A truly threedimensional s...
The cone penetration test (CPT) is one of the most widely used in-situ tests for geotechnical characterization and liquefaction assessment. When processing CPT data, the sleeve friction resistance (fs) readings must be shifted relative to cone tip resistance (qc) because of the difference in depth of the cone tip and the friction sleeve. There are...
Citations
... Liu et al. [16] suggested that even if q t is replaced by q c in order to be applied to the interpretation of conventional CPT data, the q t À R f chart from Robertson [29] was also effective. ...
... This study investigated the three soil classification charts proposed by Robertson [27,29]. The results are shown in Fig. 6 (for q t À R f chart), 7 (for Q t1 À F r chart) and 8 (for Q t1 À B q chart). ...
... Interrelationships between CPT and DMT data can validate, expand and improve correlations and applications by using existing engineering experience from one test and extrapolating to the other. Comparison of intermediate DMT parameters and those derived from CPTU data after Robertson [29] and Grabar et al. [12] was made to discuss on the equivalence/nonequivalence of CPTU and DMT data. Robertson [29] pointed out that the proposed correlations are unlikely to be applicable for all soils but regarded them as framework, which is available for future refinements. ...
The site investigation is a key part of the design of tunnel construction projects, as it provides accurate geotechnical parameters. A systematic site investigation, which consists of mainly in situ tests and laboratory sample tests, was conducted for the Haimen-Taicang river-crossing tunnel project on Yangtze River. This paper aims to analyze and compare the piezocone penetration testing (CPTU) and dilatometer test (DMT) results of both onshore and under-river subsoils to provide insights into the interpretation of the in-situ tests. The accuracy of well-documented interpretation methods based on CPTU and DMT was discussed. Current empirical correlations between in-situ test results and unit weight, undrained shear strength and constrained modulus of the subsoils were checked, and their site adaptability was discussed in detail. A series of site-specific correlations were derived based on the analysis of the in-situ tests and the comparison between the in situ tests interpretation and the laboratory results. In order to reduce the errors between testing locations caused by soil variability and get the consistent understanding of soil behaviors, CPTU–DMT correlations were reviewed and improved based on local testing results.
... The qc and the Rf are plotted on the chart to find out the major points plotted on the sectors of different colours. The major soil type has been found out to be sandy for the Dhaka soil, which is the study area, by utilizing the classification of the SBT Chart of Robertson [4,5] in Figure 1. Sandy soil indicates that there might be a mixture of both coarse grained, and clean or fine sand. ...
... Much emphasis has been placed on the category of sandy soil as 474 pairs of data from 564 pairs have been found to be sand type. Furthermore, soil type for Dhaka soil, which is the study area, has been found to be mostly sandy by utilizing the classification of the SBT Chart of Robertson [4,5] in Figure 1. ...
... Plotting qc and Rf from data of Dhaka soil on Robertson's SBT Chart[4,5] for soil classification of Dhaka. ...
Standard Penetration Test (SPT) is a very common in-situ test all over the world for its simplicity. Whereas Cone Penetration Test (CPT) is recently getting popular for its better accuracy. Both these tests are necessary for the study of stratigraphy of soil and to find out the important geotechnical properties of subsurface soil. Many empirical studies have been conducted based on the correlations between the parameters of these two in-situ tests. Dhaka soil, which has been considered in this study, is found to be mostly sandy with a mixture of silt and clay. Considering the sleeve friction, cone penetration resistance from CPT and N-value from SPT, the n-ratio for Dhaka soil has been found in this study for four categories of soil along with sand and was compared with those from other studies. Also, Multiple Linear Regression (MLR) Analysis with MATLAB has been used for the N-value prediction by generating multi-linear equations predicting N value for the four soil types. It is expected that the results will provide much better correlations on the addition of fine content as the study soil was mostly sandy.
... Interrelationships between CPT & DMT parameters can be helpful to expand and improve correlations and applications by using existing experience and databases from one test and extrapolating to the other (Robertson 2012). Robertson (2009a) reviewed published records of data from nearby CPT and DMT soundings, as well as existing correlations for geotechnical parameters, in an effort to identify possible intercorrelations. The key in this approach was the recognition that, since the main DMT interpreted parameters are normal ized, they should be correlated with normalized CPT parameters. ...
... where p 0 = corrected first DMT pressure reading, p 1 = corrected second DMT pressure reading, q t = cor rected cone resistance, f s = sleeve friction resistance, u 0 = pre-insertion in situ equilibrium pore pressure, σ v0 = in situ total vertical stress, σ' v0 = in situ effect ive vertical stress. Robertson (2009a) explained that in most of the available published records the DMT K D is normalized by σ' v0 as in the original formulation (Eq. 2) proposed by Marchetti (1980). ...
... In addition, stress normalization for K D is a debated issue. Robertson (2009aRobertson ( , 2015 suggested that a more complex normalization for K D , similar to Q tn , would likely be more appropriate, especially in sands, and future CPT-DMT correlations could use more suitable normalized parameters. However, for typical stress levels in geotechnical engineering of about 65-200 kPa (i.e., ≈ 4-20 m) the normalization method has little influence on the normalized parameters, hence updated CPT-DMT correlations using a different nor malization may not change significantly. ...
... The cone factor (N kt ) varies from 10 to 20. Detailed literature review suggests that the value of N kt may be considered as 14 as general value for different types of soils [10]. ...
... The probable reason behind this may be due to the fact that the CPT cone senses soil slightly ahead and behind of the cone tip due to the size of the influence zone. This observation is also supported by [10] who showed that the cone can sense a soil interface up to 15 times cone diameters ahead and behind, depending on the strength/stiffness of the soil and the in situ effective stresses. ...
Proper identification and characterization of subsoil profile depends on thorough geotechnical investigation. Standard Penetration Test and collection of undisturbed soil samples are age-old common techniques. But from the last decades, it has been observed that there is a major shift in this field. Confidence has been generated more into obtaining results directly from in situ testing. In situ tests (e.g. Cone Penetration Test (CPT), Standard Penetration Test (SPT), and Flat Dilatometer Test (DMT) etc.) are fast, economical and highly informative. Important engineering properties such as undrained cohesion (c u), angle of internal friction (u) and vertical drained constrained modulus (M) can be estimated by the Flat Dilatometer test with high degree of accuracy. In this paper, the undrained cohesion (c u) and constrained modu-lus (M) are obtained from Dilatometer Tests and the values have been compared with other field and laboratory test results from three different test sites in Kolkata. Apart from this, two numbers of software, namely DMT Settlement and PLAXIS 2D, were used to draw a comparison on the settlement of the foundation between the estimated value, based on constrained modulus (M) obtained from DMT, CPT tests data and conventional shear strength parameters obtained from conventional boring practices. Finally, it is concluded that geotechnical properties obtained from DMT tests are conservative in nature and settlement obtained from DMT test is well comparable with regard to estimated and observed settlement from other test results. Besides, use of DMT tests reduces overall construction cost and can be performed with confidence in difficult ground condition.
... Settlement estimations for footings in sand can be carried out by methods that use the drained elastic modulus E. 1D constrained modulus M are generally used for the estimation of long term consolidation settlements. However, for stresses below the preconsolidation stress, it can be assumed that M is approximately constant and possible to correlate with the net cone resistance (qt -v0) by means of DMT-CPT relationships represented in the Qtn-Fr chart (Robertson, 2009a(Robertson, , 2009b. ...
... Interrelationships between CPT & DMT parameters can be helpful to expand and improve correlations and applications by using existing experience and databases from one test and extrapolating to the other (Robertson 2012). Robertson (2009a) reviewed published records of data from nearby CPT and DMT soundings, as well as existing correlations for geotechnical parameters, in an effort to identify possible intercorrelations. The key in this approach was the recognition that, since the main DMT interpreted parameters are normal ized, they should be correlated with normalized CPT parameters. ...
... where p 0 = corrected first DMT pressure reading, p 1 = corrected second DMT pressure reading, q t = cor rected cone resistance, f s = sleeve friction resistance, u 0 = pre-insertion in situ equilibrium pore pressure, σ v0 = in situ total vertical stress, σ' v0 = in situ effect ive vertical stress. Robertson (2009a) explained that in most of the available published records the DMT K D is normalized by σ' v0 as in the original formulation (Eq. 2) proposed by Marchetti (1980). ...
... In addition, stress normalization for K D is a debated issue. Robertson (2009aRobertson ( , 2015 suggested that a more complex normalization for K D , similar to Q tn , would likely be more appropriate, especially in sands, and future CPT-DMT correlations could use more suitable normalized parameters. However, for typical stress levels in geotechnical engineering of about 65-200 kPa (i.e., ≈ 4-20 m) the normalization method has little influence on the normalized parameters, hence updated CPT-DMT correlations using a different nor malization may not change significantly. ...
... Not many correlations between DMT and CPT parameters (Robertson 2009b) have been published, particularly for soils with unusual behavior such as tropical soils. ...
Site investigation consists of identifying the geometry of relatively homogeneous zones and developing index, strength, and stiffness properties for the soils within these zones. The cone (CPT) and the flat dilatometer (DMT) have been used for site investigation worldwide. DMT is well-recognized for its ability to estimate settlement of shallow foundation. However, little has been published regarding the relationship between these in situ tests in tropical soils. Correlations between CPT and DMT data are investigated for three Brazilian research sites. The correlations for each site to estimate the constrained modulus from CPT data were adjusted based on DMT data. The predicted settlements based on CPT data were compared with measured settlements by in situ load tests carried out in the sites. The CPT ability to predict foundation settlements in tropical soil sites after adjusting correlations with DMT data is presented and discussed. RÉSUMÉ : L'étude de site peut être définie comme le processus d'identification de la géométrie de zones relativement homogènes et de développement des propriétés d'indice, de résistance et de rigidité des sols dans ces zones. Le cône (CPT) et le dilatomètre plat (DMT) ont été utilisés pour l'étude des sites dans le monde entier. Le DMT est bien reconnu pour sa capacité à estimer le tassement des fondations peu profondes. Cependant, peu de choses ont été publiées concernant la relation entre ces tests in situ dans les sols tropicaux. Les corrélations entre les données du CPT et du DMT sont étudiées pour trois sites de recherche brésiliens. Les corrélations pour chaque site afin d'estimer le module contraint à partir des données CPT ont été ajustées sur la base des données DMT. Les tassements prévus sur la base des données CPT ont été comparés aux tassements mesurés par des tests de charge sur plaque in situ effectués sur les sites. La capacité du CPT à prédire les tassements des fondations dans les sites de sols tropicaux après ajustement des corrélations avec les données DMT est présentée et discutée.
... Performing these two complementary tests in close proximity to each other provides a lot of subsoil data and allows for their extensive analysis. Comparative studies were conducted by many researchers (Marchetti 1980, Robertson 2009, Mayne 2016 also for loess soils (Młynarek, Wierzbicki & Mańka 2015, Nepelski n.d.). In each of these tests, it is also possible to perform seismic measurements with the use of additional accessories. ...
The paper presents an analysis of the correlation of cone penetration test CPT(U) and flat dilatometer tests (S)DMT. The tests were carried out on loess subsoil from Lublin in eastern Poland. Several CPT(U)-(S)DMT profiles from different regions of Lublin were compared. The distribution of the most important parameters was analysed, among others qc, Rf, KD, MDMT, MCPT, G0. The paper also discusses the interrelationships between these parameters and refers to the results of other researchers. The research results allowed the authors to draw preliminary correlations, which can be developed in the future. RÉSUMÉ : Cet article présente l'analyse de la corrélation des résultats des essais pénétrométriques statiques CPT(U) et des essais dilatométriques (S)DMT. Les recherches ont été menées sur le loess de Lublin, dans l'est de la Pologne. Elles comparent les résultats des différentes recherches CPT(U)-(S)DMT effectuées dans de diverses régions de Lublin. La distribution des paramètres les plus importants a été analysée, y compris qc, Rf, KD, MDMT, MCPT, G0. L'article examine les dépendances mutuelles entre ces paramètres et fait référence aux résultats obtenus par d'autres chercheurs. Les résultats ont permis aux auteurs d'établir des corrélations préliminaires, qui pourront être développées à l'avenir.
... This paper compares the records of pairs of adjacent CPT and DMT soundings at eight sites in Croatia to obtain intercorrelations between two in situ probes typical of the local sediments. Robertson [8] published a paper on this subject, with which the data of this study are compared, expression (4). He established a relationship between two in-situ tests using data from one test and extrapolating to the other. ...
... Robertson [8] proposed a correlation based on the observation that the corrected lift-off pressure (p 0 ) is equal to the excess pore pressure (u 2 ) around the probe in clays: ...
... Figure 14 shows a summary of the measured datasets in terms of log I D versus I c without excluding any data from the statistical analysis. Robertson [8] presented CPT and DMT data from published records and showed a trend between and , so it can be defined using the following relationship: ...
This paper was prepared based on in situ measurements carried out by the authors using the CPTu and DMT static penetration probes. The list of study sites includes seven specific locations in the northern parts of Croatia and one study site on the southern border of the country. The sites were selected based on the criterion of soil type, which falls into the category of soft to firm, slightly over-consolidated silty clays and silty sands. Intermediate soils are prevalent in the wider region, and most engineers deal with them in their everyday practice. For this reason, local characterization is of most importance for engineering purposes. In this investigation, results of in-situ tests are compared in order to validate the quality of the constrained modulus obtained from a CPT test to the one obtained by a DMT flat dilatometer. A comparison was made between the CPT test cone resistance and two DMT parameters—normalized modulus and horizontal stress index . Dependencies were analyzed for the main soil groups and intermediate data groups. Clay soils were divided into two subgroups based on the identification parameter , while silty soils were analyzed in three subgroups. The results for each subgroup differed significantly, and the analyses showed deviations from published values, especially for the intermediate soil groups. The usefulness of the application is demonstrated with examples at two sites, showing improvements over the most commonly used formula for the constrained modulus from the CPT test.
... This relationship is corroborated by an independent CPT-DMT study by Robertson (2009b) shown in Figure 9-26 and approximated by the following: ...
