Dynamic Cone Penetrometer 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.

The Use of Dynamic Cone Penetrometer to Predict California Bearing Ratio Value of Subgrade Soils

California Bearing Ratio (CBR) is an indirect method mostly used to investigate the strength of subgrade material for highway design. The CBR of subgrade materials can be determined from costly and time-taking laboratory or in situ CBR tests. These limitations suggest the need for an easy and low-cost in situ direct method to estimate the CBR of subgrade materials. Dynamic cone penetration (DCP) is easy, quick, and economical in situ test in geotechnical uses. However, the use of DCP test to evaluate the CBR of subgrade material is condition specific i.e., local conditions should be considered before adopting existing correlations in engineering design. The objective of this study is therefore to develop a correlation that can predict the CBR of subgrade material from the dynamic cone penetration index (DCPI). Several laboratory and field tests including Plasticity index (PI), Liquid limit (LL) and Plastic limit (PL), in situ density, and classification (sieve analysis and hydrometer analysis), CBR (unsoaked), in situ moisture content, and DCP were conducted. The suitability of the existing model to predict CBR from DCPI was checked. The prediction model was then developed using Statistical Package for the Social Sciences (SPSS) software. The result of the SPSS analysis is log (CBR) = 2.954 – 1.496log (DCPI) with R2 = 0.943. The result shows that a good correlation exist between the dynamic cone penetration indexes (DCPI) and unsoaked CBR values.

Assessment of the quality of full depth reclamation (FDR) using a dynamic cone penetrometer (DCP): a case study

The full-depth reclamation with no stabilization (FDR-NS) is widely used as a pavement rehabilitation technique. It is important to evaluate the on-site characteristics of FDR-NS materials to avoid short-term underperformance. The need for performance-based testing could then be supported by in-situ and non-destructive testing, such as dynamic cone penetrometer (DCP). DCP allows to estimate the bearing capacity of the pavement structure and to verify its homogeneity according to the depth. The objective of this research is to evaluate the applicability of using DCP to assess the quality of FDR-NS. Overall, DCP results showed a good reliability, allows to measure the effective depth of reclamation and to observe a significant reduction (average of 75 %), in terms of DCP values, between before and after the reclamation process. Thus, the potential of using DCP for FDR-NS rehabilitation was confirmed. The results from this research provide a rational basis for establishing specifications.

Developing Liquefaction Prediction Equations for Gravels Based on DPT Blow Count and Shear Wave Velocity at Field Case History Sites

Gravelly soils have liquefied at multiple sites in at least 20 earthquakes over the past 130 years. These gravels typically contain more than 25% sand which lowers the permeability and makes them susceptible to liquefaction. In other cases, a low permeability layer at the surface impedes drainage and causes liquefaction. Typical SPT- or CPT-based liquefaction correlations can be affected by large gravel particles and lead to erroneous results. To deal with these problems, we have developed liquefaction triggering curves for gravelly soils based on (1) shear wave velocity (Vs) and (2) a 74-mm diameter dynamic cone penetrometer (DPT), that are less affected by gravel particles. These correlations are based on case histories where gravel did and did not liquefy in past earthquakes. The VS-based liquefaction triggering curves for gravels shift to the right relative to similar curves based on sands. Good agreement has been obtained with liquefaction resistance from the DPT and the CPT when these methods could all penetrate the gravel in Wellington New Zealand. Correlations are developed between Vs and blow count from the DPT.

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.

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.

Comparative study on in-situ resilient modulus of subgrade estimated using in-situ modulus detector

This study presents a comprehensive evaluation of the resilient modulus of unsaturated subgrade soils using a novel in-situ modulus detector (IMD) along with various laboratory and field-testing methods. The current study employs several testing devices, including bender elements, standard dynamic cone penetrometer, and crosshole-type dynamic cone penetrometer (CDP), to assess the reliability of the IMD in estimating the resilient modulus profiles of small-scale homogeneous subgrade models in unsaturated conditions. The index properties, compaction and strength characteristics of the compacted soils, are evaluated. The resilient modulus values obtained from the IMD are compared with those obtained from repeated load triaxial tests under various stress states. Experimental results show a decrease in the penetration depth per blow with increased dry unit weight. In addition, elastic modulus and shear wave velocity increase with soil density. The resilient modulus estimated from the IMD increase with both depth and soil density. A robust correlation has been established between the resilient modulus values estimated from the IMD and those estimated from the CDP or bender element tests. Furthermore, the resilient moduli estimated from the universal model and the IMD demonstrate linear relationships with a coefficient of determination greater than 0.8. Thus, the IMD may be useful for the in-situ evaluation of resilient modulus in unsaturated subgrade soils, considering influencing factors such as soil density and confining pressure.

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

Automated signal‐based evaluation of dynamic cone resistance via machine learning for subsurface characterization

AbstractDynamic cone resistance (DCR) is a recently introduced soil resistance index that has the unit of stress. It is determined from the dynamic response at the tip of an instrumented dynamic cone penetrometer. However, DCR evaluation is generally a manual, time‐consuming, and error‐prone process. Thus, this study investigates the feasibility of determining DCR using a stacked ensemble (SE) machine learning (ML) model that utilizes signals obtained from dynamic cone penetration testing. Two ML experiments revealed that using only force signals provides more accurate predictions of DCR. In addition, the SE technique outperformed the base learning algorithms in both cases. Overall, the findings suggest that ML techniques can be used to automate the analysis of DCR with force and acceleration signals.

Recalibrated Correlations between Dynamic Cone Penetrometer (DCP) Data and California Bearing Ratio (CBR) in Subgrade Soil

Recalibrated Correlations between Dynamic Cone Penetrometer (DCP) Data and California Bearing Ratio (CBR) in Subgrade Soil

РІЗНІ ПРАКТИКИ ОЦІНЮВАННЯ МІЦНОСТІ ШАРІВ ҐРУНТОВОЇ ОСНОВИ І ДИСПЕРСНИХ МАТЕРІАЛІВ ЗА РЕЗУЛЬТАТАМИ ДИНАМІЧНОГО ВИПРОБУВАННЯ КОНУСНИМ ПЕНЕТРОМЕТРОМ

Introduction. The introduction to the paper highlights the methods of standard geotechnical tests for in situ measurements of subgrade strength or strength estimation. Problem statement. The issue of the paper concerns the interpretation and the application of the results of testing of the subgrades or granular layers of a road pavement by the dynamic cone penetrometer. Purpose. The goal of the paper consists of the analysis of practices of the subgrade strength evaluation by the conversion of the dynamic cone penetration test (DCPT) results to the nominal values of the California bearing ratio (CBR) or by plotting the subgrade profile and also of practices for the layer thickness evaluation and compaction control. Results. The main principles of DCPT were reviewed with performing the analysis of factors affecting the test results. The equations of the dependence of the nominal CBR values on the penetration index as the main result of DCPT was analyzed. The assumption was made that the difference in such equations may be determined by the differed confinement conditions under testing in accordance with which the calculated values provided by the results of testing under the triaxial confinement are higher. Also the stair-stepping effect appeared when performing DCPT on cohesive soils was reviewed.

An inexpensive and lightweight dynamic cone penetrometer for the characterization of shallow submerged sediments

Abstract Sediment compaction is an indicator of the health of benthic communities. At the same time, many of the extractive or cultivation activities on the coast take place in areas of special environmental interest and remove or compact the sediment by their own activity or simply by access on foot. Measurements of compaction or penetration resistance of marine or river sediments are not common, especially in submerged environments. Although there are devices, such as vane testers, that can be used in non‐submerged sediments, lightweight and inexpensive devices for measuring compaction in submerged sediments are rare. An apparatus for measuring sediment penetration resistance based on the dynamic cone penetrometers used in terrestrial environments is described and tested. The device is lightweight and inexpensive, and although it is intended for use in submerged sediments, it can also be used manually in sediments accessible by foot. In the process of testing the apparatus, the penetration resistance values of surfaced sediments have been compared with those obtained with a vane tester to estimate compaction. This new lightweight penetrometer provides inexpensive penetration resistance values as a measure of compaction in the sediment layer of greatest interest for the management of habitats and communities and makes it possible to establish criteria for action and to measure its effectiveness.

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.

Estimating Soil Strength Using GIS-Based Maps - A case study in Sweden

Soil strength is an important parameter for planning of forest roads and harvesting operations. Locating roads to areas with high soil strength reduce both build and maintenance costs. Locating logging trails to high strength areas minimise soil disturbances, e.g., rutting and compaction of forest soils. GIS-based maps of soil type and soil moisture can be valuable tools to estimate soil strength. The aim of this study was to evaluate the use of soil moisture map, i.e., depth-to-water (DTW), maps and soil type maps, to estimate soil strength expressed as California bearing ratio (CBR). CBR, volumetric water content, and ground penetration depth were measured in 120 sample points, separated on three soil classes (clay-silt sediments, sand sediments, glacial till) and two soil moisture classes (wet, dry). In each point, soil samples were collected for validation of the soil type maps. There was a high conformance between soil moisture predicted by DTW maps and field measurements, but conformance of the soil type between maps and field estimates varied between soil types. For sediment soils, dry soils were consistently stronger than wet soils. Soil strength of glacial till soils was more complicated with a binary CBR distribution depending on soil stoniness. Glacial till soils possible to penetrate to 20 cm depth with the dynamic cone penetrometer had CBR values close to those for sand sediments. There is a potential to estimate soil strength from DTW and soil type maps, but these variables should preferably be complemented with other data.

Review of Correlations between Unconfined Compressive Strength (UCS) Values and Dynamic Cone Penetrometer (DCP–DN) Values of Stabilized Soils

This paper discussed test methods, test and sample types, types of stabilisers and soils, applications, and limitations of various developed relationships between UCS and DCP DN values. The review of correlations between unconfined Compression Strength (UCS) values and Dynamic Cone Penetration (DCP-DN) values of stabilised soils will provide guidance on the selection of suitable regression models from what is available in the literature to enable the estimation of UCS from DCP values. The DCP test was found to be economical, rapid, portable, easy to operate and understand, and the most versatile test that provides comprehensive results. Many studies and various nations have adopted the ASTM D6951 DCP equipment for use. Previous studies show that DCP DN values are affected by the soil type, stabiliser and curing period, particle size, plasticity, moisture contents, liquid limit, dry density, UCS, confinement in mould, and investigation depth. The various existing regression models are useful for quick estimation of in-situ UCS of stabilised layers since the termination of in-situ UCS is expensive, tedious, difficult, and time-consuming. However, these regression models must be used with caution as they are dependent on material properties and other factors that influence the DCP DN values. Furthermore, the available correlations cannot be treated as an absolute substitute for laboratory values, and their application requires experience and engineering judgment. This allows further research to develop multiple regression models to correlate UCS and DCP with the same compactive effort and mould size, which will consider material properties and the effect of confinement on the laboratory DCP DN test in the standard mould.

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.

Characterization of Recycled Aggregates in Existing Pavement Base Layers

ABSTRACT The use of recycled pavement materials in transportation infrastructure projects has contributed positively to maintaining a sustainable flow of construction materials and sources. Geotechnical properties of recycled pavement materials play a major role in the suitability of such materials for use in civil infrastructure. This study aimed at evaluating the properties of recycled concrete aggregates (RCA) and reclaimed asphalt pavements (RAP) used as base layer materials in existing hot mix asphalt pavements (with service life of more than 8 years) and comparing them with virgin crushed aggregate (CA) base materials of similar service life. Coring of flexible pavement surface layers at 18 pavement sites was performed to expose the base course layer materials for sampling and testing. Then, the dynamic cone penetrometer (DCP) test was conducted in which the cone penetrated through base layers to the subgrade when possible. Thereafter, base materials were retrieved from the pavement sites for laboratory testing and evaluation. Laboratory tests consisted of particle size analysis, specific gravity and absorption, and Micro-Deval abrasion. Analysis of the particle size distribution showed the presence of high sand size fractions in both RCA and RAP base materials compared with virgin CA base materials. This indicated the recycled materials were crushed/milled to smaller size fractions or degraded under freeze-thaw cycles and traffic loads during the pavement’s service life, or both. The RCA base materials exhibited the highest absorption and mass loss in the Micro-Deval test. The DCP test results were used to predict California bearing ratio (CBR) and resilient modulus (Mr) of base materials. The predicted CBR and resilient modulus of the recycled base materials showed that RCA, RAP, and CA all had comparable strength and modulus values that were high. The investigated recycled RCA and RAP aggregates possessed properties that are comparable with the properties of the virgin CA.

Effect of Composite Portland Cement for Subgrade Stabilization and the Effect on Unsoaked CBR Value

Soil is a material that has an essential role in construction. Soils that have low bearing capacity require soil improvement. One method of soil improvement is soil stabilization using composite portland cement. Based on the results of the Dynamic Cone Penetrometer (DCP) test, the location in this study, namely Cibingbin village, Pandeglang Regency, has a bearing capacity of 2.67%, meaning that the soil at this location needs to be repaired. This study aimed to determine the effect of portland cement on physical properties and unsoaked CBR values. Variations of portland cement used were 0%, 4%, 6%, and 8%, with curing times of 0 days and seven days. The results showed that based on the unified soil classification system (USCS), the soil classification was in the CH category (inorganic clay with high plasticity, fat clay) and the maximum CBR value was obtained at 8% Portland cement variety at seven days curing time, namely 13.23%.