Penetrometer Tests Research Articles

Study of the Correlation between Pressuremeter Limit Pressure and Dynamic Resistance obtained by the Dynamic Probing Super Heavy (DPSH) of the Sands of Lome in Togo

The design of building foundations relies on a good understanding of the bearing capacity of soils, which is determined by various in situ testing methods, such as pressuremeter and penetrometer tests. The pressuremeter test provides valuable information on the strength and deformability of soils at depth, while the dynamic cone penetrometer more easily assesses the dynamic resistance of the soil under dynamic loads. In this study, correlations were established between the dynamic resistance qd measured with the dynamic probing super heavy and the limit pressure pL obtained with the Menard pressuremeter. The data collected come from geotechnical investigations carried out on sandy soils of Lome in Togo. For these soils, the ratio is in the following interval: 8.27 ≤ qd/pL ≤ 9.74. Keywords: correlation, dynamic resistance, limit pressure, sand.

Study of the Correlation between Menard Pressuremeter Modulus and Peak Dynamic Resistance Obtained by the Super Heavy Dynamic Cone Penetrometer of Sands of Lome in Togo

The bearing capacity of soils is obtained in various ways using in situ tests, especially pressuremeter and penetrometer tests which are in fact frequently used for the design of foundations. The pressuremeter provides detailed information on the resistance and deformability characteristics of soils at depth. The dynamic cone penetrometer test, on the other hand, is simpler to produce and used to assess the dynamic resistance of the soil, i.e. its behavior under dynamic loads. This study establishes correlations between the dynamic resistance qd of the soil obtained with the super heavy dynamic cone penetrometer and the pressuremeter modulus EM measured with the Menard pressuremeter. The data used in this analysis are those obtained during geotechnical investigations on sands in Lome in Togo and which combined on the same site the super heavy dynamic cone penetrometer test and the Menard pressuremeter test. It appears that for the sands studied, the EM/qd ratio can be bounded as follows: 0.60 ≤ EM/qd ≤ 0.92. Keywords: Correlation, pressuremeter modulus, dynamic resistance, sand.

Stability of kangaroo rat burrows in the Sonoran Desert: Evidence of biocementation

Kangaroo rats (Dipodomys deserti) construct complex burrow systems in loose desert sand that survive temperature and relative humidity fluctuations and storms. Animals that burrow in desert sand typically burrow in compacted sand, near plant roots, or when the soil is unsaturated. However, these processes are insufficient to explain tunnel stability of kangaroo rats. Our goal is to understand how kangaroo rat burrows remain stable in loose desert sand, intending to translate this knowledge to geotechnical engineering. A kangaroo rat habitat in the dunes of The Sonoran Desert, AZ, was selected for the study. Dynamic cone penetrometer tests performed at active, abandoned, and no-burrow sites demonstrated that the animals prefer loose sand for burrow construction. Soil samples collected from the burrows' ceilings, subsurface, and surface were characterized. Brazilian tensile strength test results showed that burrow soil has approximately 3 times greater tensile strength than the rest at dry state, which indicates increased interparticle attractive stress in burrow ceilings due to biocementation. Laboratory experiments, scanning electron microscopy, and confocal microscopy images showed that fungal and microbial biofilms provided 17 kPa increase in interparticle attractive stress at less than 1% biomass concentration, indicating potential to be used in soil improvement applications.

Slope stability analysis of colluvial deposits along the Muketuri-Alem Ketema Road, Northern Ethiopia

Slope failures are a significant natural geohazard in hilly and mountainous regions, often resulting in loss of life and infrastructure damage. The Muketuri-Alem Ketema road in Ethiopia is particularly vulnerable to landslides due to colluvial deposits on steep slopes from the higher northeastern plots to the lower Jemma River valley. This study investigates the characteristics of colluvial soil and evaluates the stability of slopes prone to landslides. It combines geophysical data, penetrometer tests, laboratory analyses, Google Earth images, and detailed field visits to assess the soil and bedrock composition and structure. Numerical methods, including limit equilibrium (Bishop, Janbu, Spencer, and Morgenstern-Price methods) and finite element methods, were used to analyze slope sections under various saturation conditions and simulate different rainfall patterns. The results indicate that the Bishop, Morgenstern-Price, and Spencer methods produce similar safety factors with minimal differences (<0.3%), while the Janbu method shows more significant variation (1.5%–5.6%). Safety factor differences for sections A-A and B-B range from 5.26% to 9.86% and 3.5%–4.7%, respectively. Simulations reveal that short-term saturation significantly reduces the stability of the upper slope layer by 20%–46.76%, and long-term saturation decreases the entire slope section by 26.81%–46.76% compared to dry conditions due to increased pore water pressure and self-weight. Long-term saturation effects, combined with dynamic loads, can further reduce colluvial soil stability by over 50% compared to a dry static state. The finite element method predicts larger failure zones than limit equilibrium methods, emphasizing the need for accurate predictions to characterize slope behavior during failure and inform stabilization decisions. This study provides crucial data for maintaining and planning the Muketuri-Alem Ketema Road, highlighting slope performance over time and the effectiveness of stabilization techniques.

Simulating lunar highlands regolith profiles on Earth to inform infrastructure development and ISRU activities on the Moon

Lunar exploration and infrastructure development near the Moon's south pole, and at other future lunar settlements, demand a detailed understanding of the geotechnical properties, structure, composition, and stratigraphy of the near-surface lunar regolith. Long term exploration and development activities will require the use of regolith as a construction material for multiple structures, and as unrefined material for resource extraction during in situ resource utilization (ISRU) activities. Upcoming robotic and human exploration will be concentrated near the lunar south pole, which has a dominantly feldspathic composition typical of the lunar highlands. Past missions to lunar highlands terrain (Apollo 16, Luna 20) provide valuable “ground truth” data regarding the geomechanical properties of highlands regolith that serve as a guide for future exploration at the lunar south pole. Lunar highlands simulant LHS-1 has well-characterized geotechnical properties and is an appropriate analogue for highlands lunar regolith in terrestrial engineering studies. Cone penetrometer testing (CPT) measurements of LHS-1 reveal a strong exponential correlation between the G slope parameter and bulk density, which allows information to be obtained regarding the density profile of simulated regolith columns directly from CPT stress versus penetration curves. We show that LHS-1 can be used to replicate the near-surface regolith stratigraphy at the Apollo 16 highland landing region in Earth-based laboratories. The ultimate CPT penetration resistance measured in the laboratory under terrestrial gravity is not directly comparable to that measured under lunar gravity, and here we derive an average reduction factor of Rf = 0.29 to scale penetration resistance values to those measured in situ on the lunar surface. Geotechnical measurements of other lunar simulants combined with experiments similar to those described herein, tailored to the terrain type of interest, will provide crucial information to guide future regolith excavation, construction, and ISRU activities on the lunar surface.

Field Evaluation and Application of Intelligent Quality Control Systems

During road construction, the accuracy of compaction work is critical for the structural stability and maintenance of the road. Although the plate load test (PLT) is commonly used for quality inspections, it is impractical to test every section due to time and cost constraints. Therefore, simpler testing methods are being extensively developed. This study compared quality inspection results using the commonly used PLT, the relatively simple dynamic cone penetrometer test (DCPT), the lightweight deflectometer (LWD) test, and an intelligent quality control system equipped with accelerometer and global positioning system (GPS) sensors in intelligent compaction (IC) rollers. The results showed a strong correlation between the conventional tests (PLT, DCPT, and LWD) and the values obtained from the intelligent quality control system. The correlation analysis between the intelligent quality control system and PLT, LWDT, and DCPT yielded R-square values of 0.69, 0.91, and 0.95, respectively, indicating significantly high correlations. The implementation of intelligent quality management systems in earthwork construction projects will facilitate a thorough verification of the compaction quality throughout all construction segments, ensuring consistent compaction across the project. By enabling real-time data acquisition and analysis, these systems differ markedly from traditional methods, reducing the frequency and necessity of manual inspections. This approach not only streamlines construction processes, but also enhances operational efficiency. As a result, integrating these intelligent systems is anticipated to significantly increase productivity by optimizing the workflow and resource utilization in earthwork construction.

Presenting a CBR Estimation Model and Compaction Characteristics of Base Layer of Pavement Using a Dynamic Cone Penetrometer (DCP) Test

Presenting a CBR Estimation Model and Compaction Characteristics of Base Layer of Pavement Using a Dynamic Cone Penetrometer (DCP) Test

Interplay of Hydroperiod on Root Shear Strength for Coastal Wetlands

AbstractThe evolution of coastal wetlands is a complex process which is difficult to forecast, made more complicated by the addition of changing climatic conditions. Here, long term ecological and geomorphological data are coupled to geotechnical measurements at a coastal wetland in North Inlet estuary, South Carolina. The coupled methodology is presented and discussed in context of understanding coastal wetland system evolution in a changing climate. Specifically, the root shear strength of Spartina alterniflora across a range of elevations was investigated using a cone penetrometer test. Elevation, shear strength, and biomass are shown to be critically interconnected. Root strength was shown to decrease with increased inundation time and decreased elevation (i.e., mudflats). Conversely, the data set illustrates the importance of maintaining key elevation ranges in relation to sea‐level to optimize wetland resilience.

Assessment of Liquefaction Potential by Comparing Semi-Empirical Methods Based on the CPT Test

Abstract Liquefaction is a dangerous and temporary phenomenon whereby water-saturated soil loses all or part of its strength. Undrained conditions associated with cyclic loading increase water pressure in soil pores, thereby reducing effective stress. The aim of this study is, on the one hand, to report on the phenomenon of liquefaction of sand, clay and silt deposits in more or less water-saturated zones in the section located at the heart of the central alluvial plain of the Oued Sebou in the mio-plioquaternary Gharb basin and, on the other hand, to study the ability of semi-empirical methods to correctly assess liquefaction potential, while specifying the most appropriate method for the area studied. The study is based on data from experimental results of static penetrometer tests between the Mnasra - Ouelad Salama zone in the Oued Sebou alluvial plain of Morocco's mio-plio-quaternary Gharb basin, made up of sandy, sandy-clay, sandy-silt and silty-sandy formations, which are more sensitive to liquefaction due to their saturation and grain size. We present and discuss the results of Olsen's method, Juang's method and Robertson's method, which are based on the CPT static penetrometer test, as well as looking at the impact of dynamic loading and soil structure on liquefaction probability index values.

Damage to monumental masonry buildings in Hatay and Osmaniye following the 2023 Turkey earthquake sequence: The role of wall geometry, construction quality, and material properties

Damage to monumental masonry buildings in Hatay and Osmaniye following the 2023 Turkey earthquake sequence: The role of wall geometry, construction quality, and material properties

Predicting soil parameters in Maroua 1st, Cameroon, using correlations of geophysical and geotechnical data

This study aims to predict specific soil parameters based on quantitative and qualitative correlations between electrical and geotechnical data. A total of 21 geotechnical boreholes followed by sampling, 21 light dynamic penetrometer tests, and 76 vertical electrical sounding surveys were carried out in Maroua 1st. The electrical resistivity data of the soil layers were obtained through 1D and 2D inversions of the ERT surveys. The geotechnical data were obtained from field tests and laboratory experiments. The statistical analysis of the entire dataset indicates that most of the samples are clay formations, as demonstrated by the means of variables and low variance coefficients, enabling qualitative identification. The distribution analysis of the parameters confirms the complexity of the physical characteristics of soils and the measurement procedures for each parameter. The Spearman's rank correlation matrix indicates that these observations can be used to propose predictive models for free swelling, allowable stress, natural water content, and electrical resistivity. Correlations between free swelling (εg) and other variables are not significant, as the degree of significance is lower than the fixed limit, except for models εg - W (R2 = 0.94), εg - ρ (Ώ.m) (R2 = 0.803), and εg - σ adm (R2 = 0.757). Grouping variables in multiple linear regression enables the development of a mathematical model. The predicted values of εg from this model demonstrate good agreement with the measured values for a validity domain of 0–16 %. The soil's natural water content has a strong correlation (R2 = 0.80 and rs = – 0.87) with electrical resistivity, meaning that an increase in water content results in a decrease in electrical resistivity. The permissible stress σadm has a strong correlation (R2 = 0.89 and rs = 0.85) with electrical resistivity. This indicates that changes in soil electrical resistivity are associated with soil stiffness.

A conditioned Latin hypercube sampling design methodology for ground-truthing transient EM resistivity models

Translating 3D resistivity models of the subsurface to relevant hydrogeological parameters such as sediment texture requires applying a rock physics transform that is ideally calibrated using co-located 1D sediment texture logs. It is difficult to select optimal logging sites in the model that span the range of observed resistivity values using expert opinion alone. Instead, we demonstrate a methodology for selecting logging sites using conditioned Latin hypercube sampling (cLHS), a maximally stratified sampling design methodology. cLHS employs simulated annealing to select sampling sites that minimize an objective function by reproducing the statistics of the resistivity model. We implement numerous preprocessing steps to isolate desirable regions within the model for logging, and we use principal component analysis to reduce the dimensionality of the model to aid the convergence of the simulated annealing procedure while preserving the majority of the model variance. Additionally, we impose an additional objective function condition to penalize the selection of sites in the resistivity model that exhibit a high degree of lateral variance. This condition is used to increase the likelihood that the sediment texture logs acquired at the selected sites correlate well with the resistivity model. We tested our approach on a resistivity model obtained using a towed transient EM system in an almond orchard in California’s Central Valley, comparing our selected sets of logging sites against the five cone penetrometer testing logs originally acquired at the site, as well as randomly selected logging sites. The sample sets selected with cLHS were consistently able to reproduce the statistics of the resistivity model and did so more effectively than the true sampling locations or the random sampling locations.

Evaluation of the effect of the mixture of soil textural compounds on the strength of the soil crust: Coding and optimization

Soil is one of the most important parts of an ecosystem. If soil particles are conserved in a basin, it will be possible for the ecosystem to survive. In this study, clay, silt and sand particles were selected as soil conservation compounds and strength and wind erosion tests were performed to assess the crust strength of these compounds. Moreover, due to the lack of clear relationships between these parameters, this research aims to identify the correlations among them. These particles were coded at specific intervals in terms of application rate and then used as inputs in Design Expert software. After 48 h, a penetrometer test was performed on crust layers. The results showed that based on significant correlations between the simulation and laboratory data, the best models are the 2FI mathematical model (strength test) and quadratic (wind erosion). The simulation results indicate that the values of R2 and Adj-R2 were 0.8994 and 0.9311 respectively, and the signal-to-noise ratio was 21.254. The interaction effect of the treatments showed that application of clay in the studied compounds increased penetration strength of the layer. Also, with the increase in clay content, wind erosion first increased and then decreased, and this trend is directly related to the characteristics of clay. Further, the accuracy of the wind erosion simulation results was R2 = 0.9561. According to the optimization results, the maximum soil resistance occurred with 15 g each of clay, silt, and sand. However, it remained constant when sand content increased. This study suggests that application of each compound creates a very different behavior in the formation of soil crust that can be used in many projects on a local and global scale.

High‐Resolution Direct Push NMR Tools for Groundwater Investigations

AbstractA small‐diameter nuclear magnetic resonance (NMR) technology optimized for use with direct push (DP) and cone penetrometer test (CPT) drilling has been developed. The DP NMR tool can be deployed through 2.25‐in. diameter DP and CPT drilling rods allowing high‐resolution NMR logging measurements to be acquired during retraction of drill rods. DP NMR technology runs from a person‐portable battery‐powered control unit and provides significantly higher resolution in both the spatial (vertical) dimension and in the time domain of the NMR measurement than previously available NMR technology. In this study, we summarize the development of two different DP NMR tools and demonstrate their application at different sites within the United States. We believe that this technology can provide a leap forward in adoption of NMR technology for high‐resolution hydrological and geophysical investigations in groundwater resources and environmental remediation applications.

Comparison of the Piezocone Penetrometer (CPTU) and Flat Dilatometer (DMT) Methods for Landslide Characterisation

The increasing occurrence of landslides worldwide causes many human casualties and huge socio-economic losses. Therefore, the fastest and most accurate characterisation of landslides is important. The objective of this study is to compare how well the flat dilatometer (DMT) test and the piezocone penetration (CPTU) test can find the depth of a sliding zone. Inclinometers were used to measure horizontal changes in the soil to ensure the depth of the sliding zone was correct. The coincidence of the results of in situ static probes, and the displacements of the inclinometers is a sure confirmation of the depth of the sliding zone. In the example of Bedekovčina and Kravarsko landslides, in situ static probes were used to obtain values of input parameters on the sliding zone for parametric sensitivity analysis of parameters. Sensitivity analysis was performed by plotting the relationship between the above parameters and the vertical effective stress σ′vo on the sliding zone. The sensitivity analysis of the parameters of 11 tested samples shows that for the parameters of the obtained DMT probe, a higher sensitivity of the parameters is obtained, closer to the values concerning the expected range, and a minor standard deviation. The parameter Kd obtained by dilatometer probing is the best indicator of the depth of the sliding zone. The literature value Kd = 1.8–2.0 on the sliding zone in this paper is extended to the range Kd = 1.8–2.5, and its detection sensitivity is influenced by over-consolidation in shallow soil layers. In general, the research results show that the dilatometer probe has an advantage over the piezocone penetrometer test for the needs of landslide characterisation.

A Case Study of Pavement Foundation Support and Drainage Evaluations of Damaged Urban Cement Concrete Roads

Surface cracks and joint deteriorations are typical premature failures of urban cement concrete pavement. However, traffic loads on the urban pavement are much lower than those on highways. Limited research has been conducted to investigate the causes of accelerated damage in urban cement concrete roads. To investigate the foundation issues that may cause the accelerated damage of urban cement concrete pavements, in this study, field evaluations were conducted to assess pavement foundation support and drainage conditions. Field visual inspections, Ground Penetrating Radar (GPR) survey, Dynamic Cone Penetrometer (DCP) test, and the Core-Hole Permeameter (CHP) test were performed. In urban residential areas with inadequate subgrade bearing capacity, cement concrete pavements are prone to early damage. Foundations with a higher content of coarse particles exhibit a higher CBR value, which can extend the service life of the pavement. The compaction of foundation materials near sewer pipelines and manholes is insufficient, leading to non-uniform support conditions. Moreover, the permeability of the foundation material can influence the service life of pavement surface structures. Foundation materials with fewer fine particles enhance drainage performance, contributing to a longer service life for PCC pavements. In areas with inadequate drainage, water accumulation reduces the bearing capacity of the foundation, thereby accelerating pavement deterioration. The poor bearing capacity and drainage conditions of the foundation lead to cavities between the surface layer and foundation material thus yielding stress concentrations on the pavement surface, which cause the formation of pavement surface cracks.

Study on performance of geocell-reinforced red clay subgrade

Three comparative treatment plans are used to study the effect of red clay subgrade reinforced with geocell. Multiple subgrade test methods including Benkelman beam, portable falling weight deflectometer, dynamic cone penetrometer and standard vehicle load tests are adopted in the field tests. Test results show that the application of geocell in red clay subgrade can enhance the overall stiffness and strength of the subgrade. The mechanism of geocell in the subgrade is studied. Geocell can provide added confinement to the subgrade soil. Compared with the red clay subgrade without geocell reinforcement, for the red clay subgrade reinforced with 0.1 m-high geocell and 0.05 m-high geocell, the rebound modulus increases by 65% and 33%, the dynamic modulus increases by 69% and 38% and the penetration decreases by 51.7% and 40.4%, respectively. A hard shell layer is formed in the subgrade when it is reinforced with geocell. The geocell-reinforced layer mainly plays the role of stress diffusion. It not only can reduce the additional stress in the subgrade but can also diminish the influence of the depth of the vehicle load.

Cyclic resistance evaluation of marine clay based on CPTu data: a case study of Shaba Wind Farm

The offshore wind farm industry has recently experienced significant global growth. This study presents a thorough site investigation and analysis of the cyclic resistance of marine clay for offshore foundation design, using the Shaba wind farm in southern China as a case study. In-situ cone penetrometer (CPTu) tests and borehole sampling are conducted to explore the geotechnical characteristics of the soils. However, the soil conditions are characterized by multiple layers and complex sedimentary components. The classification and mechanical properties, such as water content and cyclic resistances, are compared through CPTu interpretation and laboratory tests. The findings indicated that a single physical indicator cannot determine cyclic resistance. In addition, the well-established method in existing literature proved unsuitable for marine clay. Consequently, multiple regression analysis shows that a linear relationship exist between cyclic resistance and depth-corrected CPTu index [EXP(qE/fs)0.3/H], hence a new evaluation method is developed to predict the cyclic resistance of marine clay based on CPTu data. This research aims to provide more reliable guidance for geotechnical investigations, supporting the rapid expansion of offshore wind farms.

Integrated geomorphological analysis of a Mediterranean temporary pond priority habitat: the Lago del Capraro doline (Salento peninsula, Italy)

The Lago del Capraro doline (Salento peninsula, southern Italy), a valuable Mediterranean Temporary Pond (MTP), has been investigated aiming to define its geomorphological features and to collect data about the local hydraulic regime. At the bottom of the Lago del Capraro doline, in fact, a small temporary pond appears soon after major precipitation events as that one of autumn 2013. The morphological survey shows that this solution doline is placed on a karst plain surface stretching at about 70 m of altitude; the doline has an elliptical shape with the major axis 130 m long whereas the length of the minor axis is about 100 m. It shows a flat bottom, placed at about 65 m above m.s.l., due to the presence of a colluvial sandy clays filling, bordered by steep limestone slopes about 5 m high. Geophysical surveys and a cone dynamic penetrometer test allowed a detailed geological model to be realized. In particular, ERT and seismic refraction models revealed the geometry and the thickness of doline filling deposits as well as the preferential infiltration zones of surface waters. Interestingly, the cone penetrometer test reveals that resistance decreases downward in the filling lower part, most likely because of the active solution process at the doline bottom. The results of this study suggest an increase of surface water infiltration at doline bottom in the next future so that the development of a pond will be an increasingly rare event, partly compensated by the clustering of rainy periods during autumn months as expected in the future by climate models.

Hammer weight and dropping height effects on dynamic response in densely-packed geo-materials

This study aims to investigate the dynamic cone penetration index (DCPI) and dynamic responses during instrumented dynamic cone penetration test at fixed-end condition (e.g., dense layer). Several types of hammer weights and heights at fixed potential energy (45.13 N∙m) is applied on the instrumented dynamic cone penetrometer (IDCP) tests. Test results show that the instrumented dynamic cone penetration index (IDCPI) is proportional to the DCPI with various gradients lower than 1.0 due to the influence of hammer weight on drivability. Dynamic responses change with respect to the end boundary condition (e.g., dense or loose layer) and location at the head or tip. In addition, the transferred energy varies with respect to the end boundary condition, location, hammer weight and height. For layer characterization, the end boundary condition should be primarily considered as well as hammer weight and height regarding drivability.