Cone Penetration Test Research Articles

Reliable off - road trafficability assessment hinges on in - situ penetration testing that captures depth - dependent soil strength across moisture states and translates it into operational pass/fail decisions. We present a field - deployable workflow centred on c one (static) and dynamic penetration methods. In the static branch, Cone Penetration Tests (CPT) advance a conical probe at a constant 20 mm s⁻¹, logging cone resistance (q₍c₎) and sleeve friction (f₍s₎) continuously or at 10 – 20 cm intervals; in the dynami c branch, DPL/DPM/DPH/DPSH tests derive specific dynamic resistance from standardized hammer blows with friction corrections at 1 m steps. From penetration records we compute Cone Index (CI) and Remoulding Index (RI) and derive the Rating Cone Index (RCI = CI·RI) for dry, moist, wet conditions, anchored to laboratory - verified USCS classes. We compile RCI look - ups for dominant soils (e.g., SM: 119 → 72 → 25 for dry→moist→wet) and demonstrate the operational rule by comparing RCI with Vehicle Cone Index (VCI₁ , VCI₅₀): at the Živanice site (USCS SM, moist ≈ 51 %), RCI₂ ≈ 72, thus vehicle classes with VCI ≤ 72 are passable, whereas higher - demand classes are not. Penetration methods deliver continuous or quasi - continuous strength profiles, outperforming point sam pling for heterogeneity detection, but show reduced reliability in gravelly/stony and organic horizons and in impermeable cla ys exhibiting a “rubber effect,” and are sensitive to moisture stratification. The workflow (CPT/DPT → CI, RI → RCI → RCI ≥ VCI dec ision) supports rapid, reproducible trafficability mapping and provides clear guidance on when to pair penetration testing wi th core drilling or auxiliary geotechnical probes.

The 2023 Kahramanmaraş earthquake sequence significantly impacted southeastern Türkiye. A comprehensive field investigation of 40 cone penetration tests and 7 seismic cone penetration tests was conducted to characterize the subsurface conditions of several areas affected by liquefaction in the port city of İskenderun. The investigations were performed at a key seismic station in the area, five areas with differing liquefaction-induced building settlements, and three lateral spread sites. The reclaimed shoreline area, which exhibited the most significant liquefaction effects, is underlain by thick medium dense clean sand deposits. Ground shaking characteristics in the investigated areas are estimated and essential subsurface data for developing high-quality field case histories are developed to support studies of liquefaction triggering and effects in İskenderun. In this context, it contributes to advancing liquefaction engineering and informs seismic hazard mitigation strategies in urban areas.

This study presents a forensic investigation of the catastrophic failure of the La Luciana Tailings Storage Facility (TSF) in Reocín, Spain, in 1960. The collapse released approximately 300,000 m3 of tailings, causing 18 fatalities, extensive flooding of farmland and lakes, and the contamination of the Besaya River, leading to long-term environmental degradation. The analysis integrates historical documentation, cartographic evidence, in situ testing, laboratory analyses, and numerical modelling to reconstruct the failure sequence and identify its causes. Geotechnical characterization based on cone penetration tests (CPTs), shear wave velocity profiles, and laboratory testing revealed pronounced heterogeneity, with alternating contractive and dilative layers. Hydraulic analyses indicate permeabilities from 10−5 m/s in sand dam materials to 10−9 m/s in fine-grained pond deposits, with evidence of capillary saturation exceeding 20 m, favouring excess pore-pressure accumulation. Limited equilibrium and finite element analyses show that when the decant pond was within ~20 m of the dam, the factor of safety dropped to unity, triggering retrogressive flowslides consistent with field evidence. The results underline critical lessons for TSF governance: maintaining unsaturated tailings, ensuring efficient drainage and decant systems, and monitoring pond proximity to the dam. These are essential to prevent flow failures. This research also demonstrates a replicable forensic methodology applicable to other historical TSF failures, enhancing predictive models and informing modern frameworks such as the EU Directive 2006/21/EC and the Global Industry Standard on Tailings Management (GISTM).

This study evaluates and optimizes empirical correlations between shear wave velocity (Vs) and cone penetration test (CPT) data for various soil types in Hungary. A comprehensive database of 914 data pairs was compiled from multiple cities with diverse geological conditions, incorporating SCPTu and MASW measurements. Over 40 existing Vs–CPT correlations were statistically assessed using parameters such as RMSE, RD, K, CVK, and RI to determine their accuracy across different soil types and depositional settings. The most promising correlations were further refined using regression analysis, leading to the development of improved models tailored for Hungarian soils. These new correlations were evaluated both graphically and statistically, showing enhanced predictive performance, particularly for coarse-grained soils. The final proposed models demonstrate significant reductions in estimation error, with RMSE improvements exceeding 35%. This work provides geotechnical engineers in Hungary with robust, site-adapted tools for seismic site characterization and supports safer and more reliable subsurface profiling practices.

Precise calculation of soil bearing capacity is critical in geotechnical engineering to ensure ground stability and structural safety. Traditional evaluation techniques such as the Standard Penetration Test (SPT), Cone Penetration Test (CPT), and Plate Load Test (PLT) are well-established but often time-consuming, labor-intensive, and spatially constrained. This study presents a semi-automated, real-time method for estimating soil bearing capacity by integrating torque, force, and rotational speed sensors into conventional drilling equipment. Unlike prior Measuring-While-Drilling (MWD) approaches, which have largely focused on granular formations and deeper borehole profiling, this work introduces a custom-built torque measurement system specifically designed for shallow-depth, low-permeability clayey soils. The system offers improved sensitivity to subtle resistance changes encountered during cohesive soil penetration, thereby enhancing prediction accuracy in scenarios where conventional MWD systems typically underperform. Laboratory and field tests were performed on four clayey soil types (CH, MH, SC, CL), and the collected drilling parameter data were analyzed using Multiple Linear Regression (MLR) and Response Surface Methodology (RSM). The MLR model explained 95.6% of the variability in soil bearing capacity (R2 = 0.956, MAPE = 7.87%), although it was limited in capturing non-linear interactions. In contrast, the RSM model accounted for 99.7% of the variability (R2 = 0.997, MAPE = 0.72%) and more effectively modeled the complex relationships among drilling parameters. Among all inputs, torque emerged as the most significant predictor of bearing capacity. The developed framework enables faster, more cost-effective, and sensor-integrated evaluation of soil strength, especially for cohesive soils offering a practical alternative to conventional testing. Future work will extend this approach to mixed and granular soils, deeper borehole conditions, and adaptive, ML-driven real-time control systems to enhance field-scale geotechnical applications.

Low-gravity experimental simulation is essential for advancing extraterrestrial geotechnical research, yet existing techniques face limitations in cost, duration, and scalability. This study presents a novel ground-based low-gravity system founded on the Hydraulic Gradient Similitude Method (HGSM), which applies the upward seepage force to counteract gravity. A first-generation small-scale apparatus was developed by modifying a conventional triaxial system, integrating a precision-controlled water supply system, a kaolin-boundary-modified triaxial chamber, and a cone penetration test (CPT) module. Key innovations include: (1) stable low-gravity environments (>72 hours) with a gravity ratio (γ*) adjustable from 1/6 (lunar gravity) to 1 (terrestrial gravity); (2) compatibility with conventional granular materials (e.g., quartz sands and lunar regolith simulants); and (3) high measurement precision validated through calibration tests. Experimental results confirmed the capability of the system to simulate low-gravity CPT responses, indicating notable changes in shear resistance mechanisms under reduced gravity. Comparative analysis with existing experimental data and discrete element simulations of CPT under low-gravity further demonstrated the system's reliability. This work provides a cost-effective, long-duration platform for simulating quasi-static geotechnical processes in low-gravity environments, offering a promising solution for pre-mission equipment testing and data interpretation in extraterrestrial exploration.

Abstract: This paper highlights the extended applications of the Cone Penetrometer Test (CPT) for geotechnical decision support in the determination of depth of foundation embedment, optimum depth of excavation, vertical settlement distribution, determination of total consolidation settlement and the assessment of deep shear failure risk with the use of case studies in the Niger delta. These applications are more critical in site conditions where retrieval of soil sample is difficult due to extremely weak or where soil layers are very thin such that are missed during regular boring programmes. In these instances, the (CPT) serves as a vital geotechnical analysis for better and informed decisions, offering economical, high-resolution, nearly continuous data for accurate identification of soil layers and boundaries, efficient and reliable data for various applications, including pavement, swamp rig and offshore foundation design. The CPT data can often be integrated with data from other sources, processed through various analytical and modelling techniques to unravel findings that facilitate strategic and operational choices. Its advantages of rapid data acquisition, cost-effectiveness, and the ability to characterize soil conditions over large areas, which aids in foundation design and risk assessments, provide the enablement for geotechnical analysis and decision support.

Assessing the Possibility of Driving Piles in Plastic-Frozen Soils Based on the Data of Thermal Cone Penetration Tests

The Kulan Kampak Bridge in Pangkalpinang City is planned to replace an old community-built bridge that no longer meets the increasing demands of traffic flow, regional connectivity, and access to key destinations such as the University of Bangka Belitung and local tourism areas. This study aims to analyze the design of the bridge’s superstructure, substructure, and foundation in accordance with technical standards SNI 1725:2016, SNI 2833:2016, and Bina Marga guidelines. The methodology includes field data collection, literature review, load calculation, structural analysis, and design verification for strength, stability, and safety. The superstructure is designed using reinforced concrete T-girders with a total width of 7 m, while the substructure consists of a wall-type abutment. The foundation employs pile foundations based on cone penetration test (CPT) data, with hard soil layers found at depths of 10–14 m. The calculation results indicate that all structural elements meet the required strength, stability, and 50-year design life. This research produces a technical design that can serve as a reference for bridge construction, expected to improve connectivity, support economic activities, and enhance sustainable transportation in Pangkalpinang City. Keywords : Bridge Design, Superstructure, Substructure, Pile Foundation

Abstract Drilled displacement pile (DDP) installation has the potential to induce soil densification, and improve the soil response (e.g., shear strength and stiffness) around the borehole. An evaluation of pre- and post-pile installation soil properties surrounding newly installed DDPs has been carried out by interrogating data from 11 construction sites where Cone Penetration Tests (CPT) were performed before and after pile construction (i.e., CPTPRE and CPTPOST). CPT key measurements, i.e., tip resistance ( $$q_{{\text{c}}}$$ q c ) and sleeve friction ( $$f_{{\text{s}}}$$ f s ) were corrected for overburden stress to obtain the normalized cone resistance ( $$Q_{{{\text{tn}}}}$$ Q tn ) and normalized friction ratio ( $$F_{{\text{r}}}$$ F r ), and synthesized hereafter to obtain the Normalized CPT Soil Behavior Type Index ( $$I_{{\text{c}}}$$ I c ). An analysis of pre- and post-pile installation soil data suggests the change in CPT-based soil resistances to be dependent on the $$I_{{\text{c}}}$$ I c , q c, soil fines content (FC), and pile spacing. Sandy sites exhibited clearly traceable improvement of up to 4.5 times their initial resistance when original soil conditions fell within the SBTn zones 4 and 5, and FC remained below 30%. Soils above Robertson’s contractive-dilative (CD) line showed much less improvement potential (~ 1.5). Cohesive sites exhibited both: a reduction and improvement of resistance, with clear dependency on post-installation time elapse. Little to no improvement was observed for stratified soil profiles, regardless of their initial properties. Outside the pile group, a spatial analysis indicated that the largest improvement occurred within 1 pile diameter (D) from the pile, while little to no improvement was observed beyond 2D. The greatest improvement was observed in CPTPOST testing executed at the midpoint of a group arrangement of at least 3 piles with spacing of ≤ 3D. Case studies further showed the improvement potential of silty soils ( $$I_{{\text{c}}}$$ I c ~ 2.6–2.9), and the improvement in interbedded cohesionless soil layers with a thickness of more than 1 m in mixed soil profiles, where drainage in upper and lower layers is available. The analysis of cohesionless soils in the SBTn chart demonstrates how this construction method can also be implemented to mitigate the risk of liquefaction of intermediate sands.

This study develops geotechnical zonation maps of soil bearing capacity (Q) in Banjarmasin, Indonesia, an area characterized by soft soils. A total of 333 Cone Penetration Test (CPT) data points and five Pile Driving Analyzer (PDA) test locations were analyzed. Bearing capacity was estimated using the Meyerhof, Schmertmann, LCPC, and Begemann empirical methods. Comparison with PDA results indicated that the Schmertmann method had the closest alignment, making it the basis for further analysis. Using this method, Q-values were predicted at depths of 5, 10, and 25 m. Spatial interpolation using Inverse Distance Weighting (IDW) and Ordinary Kriging was applied to produce continuous bearing capacity maps. Cross-validation showed Kriging performed better at greater depths, while IDW had slightly better accuracy at shallow levels. These findings highlight the influence of soil depth on interpolation performance and confirm that CPT-based mapping, validated by PDA data, is a reliable and cost-effective approach for preliminary foundation planning in soft soil regions.

A seismic integrated deep learning approach for prediction of offshore wind site cone penetration test data

Reinforced retaining walls are critical components of urban infrastructure, yet failures continue to occur due to complex geotechnical and environmental factors. This study investigates a collapse case, focusing on the influence of water infiltration from a damaged sewage pipe near a manhole. Photo documentation and portable dynamic cone penetration (DCP) testing were conducted to evaluate subgrade strength and identify localized weaknesses. Results revealed significant variability in ground rigidity, with particularly low resistance values near the manhole, indicating deterioration caused by seepage and soil softening. Stability analysis using MSEW software, under both static and seismic conditions, confirmed that affected wall sections did not meet safety requirements. Based on these findings, targeted remediation measures are proposed, including soil nailing, low-pressure grouting, and embankment reinforcement, complemented by continuous monitoring using displacement targets and inclinometers. This integrated approach offers both diagnostic insight and practical strategies to improve the design, maintenance, and resilience of MSE retaining walls, providing valuable guidance for engineers and decision-makers in preventing similar failures in densely built urban environments.

Abstract We present a method to update the geospatial liquefaction model used by the U.S. Geological Survey’s near-real-time ground failure product with subsurface geotechnical data. The geospatial model estimates liquefaction probability from peak ground velocity (via ShakeMap) and geospatial susceptibility proxies. In many regions, additional information relevant to constraining liquefaction likelihood is also available, including surface geology maps and subsurface geotechnical measurements. There is currently no mechanism to use these data in the ground failure product liquefaction model, even though these data could provide more precise constraints on spatial variations in the lithologic character of the soil (surface geology) and direct measurements of the subsurface mechanical properties that affect liquefaction occurrence and severity (geotechnical measurements). In this study, we develop a method to integrate these data with the geospatial model and assess how these data can improve regional-scale predictions. We develop a Bayesian updating framework and apply it to the 1989 magnitude 6.9 Loma Prieta, California, earthquake, for which mapped observations are available to evaluate performance. We constrain the Bayesian framework with 373 Northern California cone penetration tests and liquefaction susceptibility classes based on the mapped surface geology. This Bayesian model incorporates geotechnical information into the geospatial model and more accurately predicts liquefaction occurrences than the geospatial model, while sacrificing less accuracy in terms of predicting the absence of liquefaction than the geotechnical model. In future applications, this approach could be adapted to update other geospatial models using locally available subsurface data.

Abstract Urban seismic hazard assessments must account for local soil conditions that can significantly alter ground motion characteristics. This study presents a nonlinear one-dimensional (1D) site response analysis for four locations within Budapest’s District XIII—an area characterized by Quaternary Danube sediments underlain by Tertiary clays. The characterization of the seismic subsurface was performed using a multichannel analysis of surface waves (MASW) and seismic cone penetration tests (SCPT) that provided detailed shear wave velocity (Vs) profiles. These profiles were used in nonlinear simulations, including seven spectrum-matched ground motion records. The results demonstrate a pronounced site amplification effect, particularly in the short-period range (0.2–0.4 seconds), which aligns with the natural periods of low-to-midrise buildings typical of the district. Notable inter-site variability was observed, which was influenced by differences in soil stiffness and stratigraphy, with peak amplification factors reaching up to 2.6. The results provide a valuable guideline to formulate the new Hungarian National Annex of Eurocode 8.

ABSTRACT The mechanical behavior of lunar regolith is highly influenced by its diverse mechanical properties, which are critical for geotechnical engineering activities during lunar exploration missions. Cone Penetration Test (CPT) serves as a key method to investigate these properties, while numerical simulation provides an effective approach for replicating the lunar conditions. In this study, the Discrete Element Method (DEM) was employed to simulate CPT on lunar regolith simulants with varying internal frictional angles (from 33.6° to 49.7°), achieved by simulating the interlocking force among particles to reflect the natural regolith properties at different depths. Microscale analysis revealed that specimens under terrestrial gravity exhibit stronger particle interactions and volumetric strain compared to lunar gravity, although the macroscopic shear strength remains minimally affected. During the CPT process, the variation of contact force, particle displacement, and velocity is concentrated around the cone, with the affected area expanding as the shape parameter increases. The penetration results show that cone tip resistance ( q c ) increases approximately linearly in the initial stage before stabilizing, while side frictional resistance ( f s ) reaches its peak value in the beginning stage and then declines gradually. Both q c and f s increase with the strength of the specimen, with values approximately 19.1% higher for q c and 17.1% higher for f s under terrestrial gravity compared to lunar gravity. This study offers a reference for future lunar surface experiments and geotechnical assessments.

Cone penetration test (CPT)-based soil classification and stratification with consideration of data cross-correlation and noises

Measuring-while-drilling (MWD) techniques have great potential for use in geotechnical engineering research. This study first addresses the current use of MWD, which consists of recording data using sensors in a drilling machine operating on site. It then addresses the currently unsolved problems of quality control in drilled piles and assessments of their interaction with the soil under load. Next, an original method of drilling displacement piles using a special EGP auger (Electro-Geo-Probe) is presented. The innovation of this new drilling system lies in the placement of the sensors inside the EGP auger in the soil. These innovative sensors form an integrated measurement system, enabling improved real-time control during pile drilling. The most original idea is the use of a Cone Penetration Test (CPT) probe that can be periodically and remotely inserted at a specific depth below the pile base being drilled. This new MWD-EGP system with cutting-edge sensors to monitor the soil’s impact on piles during drilling revolutionizes pile drilling quality control. Furthermore, implementing this in-auger sensor system is a step towards the development of digital drilling rigs, which will provide better pile quality thanks to solutions based on the results of real-time, on-site soil testing. Finally, examples of measurements taken with the new sensor-equipped auger and a preliminary interpretation of the results in non-cohesive soils are presented. The obtained data confirm the usefulness of the new drilling system for improving the quality of piles and advancing research in geotechnical engineering.

This paper presents a full-scale field trial where distributed acoustic sensing (DAS) was explored as a novel technology to assess the quality of dry deep mixed columns, both for downhole testing and for surface wave testing. Optical fibres were installed vertically in columns and horizontally over the improved ground with geophones placed parallel to the optical fibre for validation. The test results show that DAS could reliably be used for downhole testing and to quantify the shear wave velocity (Vs) in the improved columns. Interpreted Vs ranged from around 190 to 400 m/s depending on column configurations, with a difference within ≈12% between the geophone and DAS data. Laboratory testing and cone penetration tests were also used to predict Vs in the columns, which gave results similar to those obtained from geophone and DAS data. The surface wave testing showed limitations in resolving the deep mixing columns using either geophone or DAS data, possibly due to a short array length, relatively low area replacement factor, and columns stiffness. Important practical considerations of DAS applicability in deep mixing are discussed, particularly gauge length versus wavelengths effects, coupling, and DAS directional sensitivity.

The current study compiles a database named CPT-USCS/3/2017 that consists of 2017 pairwise cone penetration test (CPT) versus Unified Soil Classification System (USCS) category data from 228 global sites. The current study also proposes a novel hierarchical Bayesian model (HBM) framework named USCS-HBM to learn the inter-site and intra-site characteristics in the database. The USCS-HBM trained by the database can produce a prior model for the target site, and this prior model is updated by the sparse target-site data into the quasi-site-specific model. The resulting quasi-site-specific model can be adopted to predict USCS categories based on CPT measurements. The proposed USCS-HBM framework explicitly addresses the challenge of site uniqueness in CPT-based soil classification as well as the practical challenge of sparse target-site data. Case studies and extensive cross-validations showed that the proposed USCS-HBM framework can provide meaningful prediction results for USCS categories based on CPT measurements even if the target-site data are sparse.