Dynamic Cone Penetrometer Research Articles

Meta-Analysis of Soil Property Relationships and Construction Platform Design

This paper introduces the concept of using an existing low-volume road design method to design the lower granular layers within a mechanistic-empirical design to ensure an adequate construction platform. The DCP-DN design method was chosen because it has advantages over other cover-based empirical methods in this context, including utilizing a full-depth measurement and requiring a balanced layer profile. To implement the DCP-DN method and use field Dynamic Cone Penetrometer (DCP) data in the mechanistic-empirical design, a relationship to convert between stiffness and DCP penetration index was required. A new set of internally consistent relationships between various soil strength and stiffness parameters was thus developed, using a meta-analysis of 126 models published since the 1960s. These were used to develop a new nomograph for estimating the properties of various soils.

Evaluation of Dynamic Resistance for Application of Portable In-situ Device to Extra Target Depth

The strength profiles of the subgrade must be assessed for the prediction and prevention of geo-hazards. This study aimed to evaluate the dynamic resistance (qd) for the application of an instrumented dynamic cone penetrometer (IDCP). An IDCP test and a cone penetration test (CPT) were conducted at an equivalent site up to the extra target depth. The dynamic cone penetration index (DCPI), N-value (NIDCP), and qd were estimated from the IDCP test, and the static resistance (qc) was measured from the CPT. The test results show that the DCPI, NIDCP, and qc can be used to detect the loose and hard layers; however, the NIDCP might underestimate the strength profile in an extra target depth owing to the excessive energy loss. However, qc has a linearly proportional relationship with qc, which considers the transferred driving energy at the cone tip. Thus, the qd estimated from the IDCP test can be used for reliable strength assessment at the extra target depth.

Lime Treatment of Lake Texcoco Clays with Some Insights on the Application of Deep Mixing Columns

The soils across Lake Texcoco (LT) basin are notorious for the presence of highly compressible salt-affected lacustrine clays. The geological formation of the area accompanied by the unmonitored flow of water from Mexico City region has resulted in a unique sodium-rich clay that is highly plastic (plasticity index~200), and impermeable ( k~1.5 × 10−9 m/s) and possesses low compressive strength (unconfined compressive strength < 10 kPa). Over the last few decades, the entire basin has settled at an average of 13.2 cm per year and will continue further with increased loads as a result of rapid urbanization. In planning a solid foundation for the airport, as well as developing the surrounding area, trial sections were built to analyze the effect of quicklime (CaO) on the natural clay s physical, chemical, and engineering properties through laboratory testing. The lab-scale investigations were accompanied with field measurements using the variable energy dynamic cone penetrometer (DCP) and plate load tests. Additionally, a numerical analysis of the effect of deep mixed columns (DMC) to reduce consolidation settlement was performed. The numerical analysis comprised of various DMC stabilizers, loading pressures, column lengths, and area replacement ratios. DMC lengths were observed to be the most dominant parameter to reduce consolidation settlements. Settlement reduction was more sensitive to the area replacement ratio for end-bearing columns, and to the loading pressures for floating columns. Based on the stabilizers evaluated, a combination lime and Portland cement performed the best across all loading pressures and column lengths. Other stabilizer combinations also had a remarkable effect on limiting the consolidation settlement.

Application of automated cone penetrometer for railway investigation using correlations with DCPI and deflection modulus

Portable in-situ devices have been used for characterizing low accessible field, such as the railway subgrade. In this study, the automated cone penetrometer (ACP) was designed for the application on the railway subgrade. ACP is composed of the cone tip, driving rod, and hydraulic hammer system. The hydraulic motor lifts and drops the 294.3 N hammer from a height of 200 mm such that the potential energy of 58.9 N m impacts the driving rod. The N-value (NACP) from the ACP test was compared with the dynamic cone penetration index (DCPI) from the dynamic cone penetrometer (DCP) test. The test results show that the NACP and DCPI profiles show opposite trend owing to the inverse concept of the unit. From the correlation of DCPI and NACP, the limitation of DCPI reveals owing the minimum manually measured value of 1 mm/blow. Additionally, the evaluation of the deflection modulus (EFWD) using NACP is more efficient than that using DCPI. Based on the result of this study, we suggest that ACP can be used for strength and stiffness evaluation of railway subgrade rapidly and reliably.

Development of Prediction Models for Performance of Flexible Pavements in Kansas with Emphasis on the Effects of Subgrade and Unbound Layers

This study resulted from the need for better consideration of subgrade and unbound layers on the performance of flexible pavements in Kansas. Thus, the main objective was to develop pavement performance prediction models with emphasis on the effects of subgrade and unbound layers. To this end, pavement distress data, which were collected over several years across the state of Kansas, including rutting, fatigue cracking, transverse cracking, roughness and core analysis, served as the input data into statistical models. The effects of subgrade and unbound layers were represented by the corresponding results of dynamic cone penetrometer (DCP) tests and thickness of the unbound layer. In addition, traffic volume was represented by average annual daily truck traffic (AADTT). Multiple statistical analyses identified positive correlations of dynamic cone penetration index (DPI) and rate of total rutting, and DPI and percent of good core. Negative correlation was discovered between DPI and fatigue cracking code one, and DPI and percent of poor core. AADTT was positively correlated with transverse cracking codes one and two while it had no correlation with transverse cracking code zero. Thickness of the unbound layer was negatively correlated with pavement roughness and percent of poor core, while it was positively correlated with the percent of good core. Finally, the recommendation for minimum acceptable value of California bearing ratio (CBR) was provided based on the correlation between DPI and rate of change of rutting code. The recommendation enables the selection of a CBR value based on the number of years required for unit increase in the rutting code.

Engineering geomorphological reconnaissance of the December 2018 Waimata Valley mud volcano eruption, Gisborne, New Zealand

Gisborne (North Island, NZ) is affected by rainfall-induced landslides, earthquakes and tsunami, as well as mud volcanoes (MVs). The latter form via upward mobilization of Eocene–age sediments, and have not been studied from an engineering geological standpoint, so the 15 December 2018 Waimata Valley MV eruption provided a unique opportunity. The event erupted c. 16 900 m 3 of mud, forming an elevated vent area, and three mudflows propagating north, east and south. Scanning electron microscopy (SEM) identified smectite as the dominant clay in the Sr-rich mud, and Atterberg limits indicate high plasticity. In-situ testing using dynamic cone penetrometer and shear vane (3–168 kPa) revealed wide variability in strength properties with depth, while ring shear values are 11.3–13.5°. A fault extends NW beneath the Waimata Valley MV, coinciding with the pre-existing Arakihi Road MV. The Waimata Valley MV area was subject to uplift and cracking during the September 2016 Te Araroa earthquake ( M w 7.1), which caused increased activity at pre-existing mud volcanoes at that time. Geodetic data for the Gisborne district shows an uplift phase culminating around the December 15 2018 MV eruption, followed by the commencement of a Hikurangi subduction zone ‘slow slip event’. Nevertheless, relationships between tectonics and MV eruptions remain equivocal.

Methodology of layers’ compaction control through dynamic cone penetrometer (DCP)

Methodology of layers’ compaction control through dynamic cone penetrometer (DCP)

Long-Term Performance of Flexible Pavements Constructed on Recycled Base Layers

There has been an increased interest in using reclaimed asphalt pavement (RAP) aggregates as a base course in Wisconsin for the offered economic and environmental benefits. Laboratory studies showed that RAP can have resilient modulus values higher than typical natural aggregates, and can also have higher durability, especially in freeze–thaw cycles. However, it is also recognized that RAP exhibits temperature sensitivity and larger permanent deformations than natural aggregates. How these characteristics manifest themselves in the northern U.S. climates can only be assessed by long-term observation of field performance. Wisconsin Department of Transportation (WisDOT) has been using RAP as a base course for over 30 years. The qualitative assessment of WisDOT roads constructed with RAP showed they are performing adequately. However, this impression has not yet been verified quantitatively. This paper presents a quantitative assessment and comparisons for field performance of pavement test sections constructed with RAP and natural crushed aggregate (CA) base course layers in Wisconsin. The performance was evaluated using pavement distress surveys of roadways containing RAP and CA, falling weight deflectometer (FWD), dynamic cone penetrometer (DCP) tests, and analysis of WisDOT’s available data. Based on the field evaluation, the performance of the hot mix asphalt (HMA) pavements with RAP was found adequate and comparable to those with CA base course layers. A recommendation was given that WisDOT shall continue the practice of using RAP in base course layers of HMA pavements, given proper quality checks for materials, and proper quality control/quality assurance measures being applied during construction.

3D response surface modeling based in-situ assessment of physico-mechanical characteristics of alluvial soils using dynamic cone penetrometer

Dynamic cone penetrometer (DCP) is the quickest and cheapest in-situ probing apparatus to estimate the soil stiffness; however, insufficient correlations are available to directly assess various physico-mechanical characteristics of natural alluvial soils using DCP. The key purpose of this study is to statistically equate the in-situ DCP test outcomes to different physico-mechanical characteristics of alluvial soils. For this purpose, in-situ DCP tests were performed at 26 different locations in the Indus plane, and corresponding undisturbed specimens were collected for laboratory testing. Various physico-mechanical characteristics of soil i.e., natural water content (wn), natural dry unit weight (γd), unconfined compressive strength (qu), deformation modulus (E50), strain at failure (εf), natural void ratio (en) and California bearing ratio (CBR) were determined in the laboratory. Initially, the regression-based models were established for γd, qu, E50, εf, en, and CBR using dynamic cone penetrometer index (DCPI) as a solitary predictor. Afterward, predictive models of the aforementioned parameters were developed based on wn integrated DCPI by quantifying the best-fit trend line and three-dimensional (3D) response surface among pertinent dependent and independent variables. In addition, it is found that the models developed using 3D response surface modeling hold 8.2–42.4% lesser error than the regression-based models developed in the current study. Moreover, results show that the DCP based assessment of soil is influenced by wn and independent of consistency limits and soil type of the alluvial soils.

Aggregate Subgrade Improvements Using Quarry By-Product Fines: A Case Study

This paper presents a case study for constructing aggregate subgrade improvement (ASI) layers using quarry by-product aggregates (QBA)—a quarry mix of large primary crushed rocks (PCR) and sand-sized quarry fines. The construction took place at Larry Power Road in Bourbonnais Township in Kankakee County, Illinois, where the Illinois Department of Transportation (IDOT) placed two QBA mixes for performance evaluation. The first mix (QBA_M1) consisted of 45% quarry by-products (QB) and 55% railroad ballast-sized PCR. The second mix (QBA_M2) consisted of 31% QB and 69% PCR. Two conventional ASI sections with only PCR were also constructed. All sections consisted of a 229 mm (9 in.) QBA/PCR layer topped with a 76 mm (3 in.) thick dense-graded capping layer. Laboratory studies preceded the construction to recommend optimum QB percentages for the QBA materials and construction practice. The quality and uniformity of the construction was ensured through field testing using dynamic cone penetrometer (DCP), lightweight deflectometer (LWD), and falling weight deflectometer (FWD). The segregation potential of the QBA mixes was monitored by visual inspection, aggregate stockpile sampling, and image analysis techniques. Short-term field evaluation of the constructed QBA layers, particularly QBA_M2 with 31% QB, showed no evidence of major segregation. The QBA ASI layers had slightly lower but comparable strength and stiffness profiles to the conventional ASI sections. The use of QBA materials in ASI was therefore field validated in this case study as a sustainable construction practice to provide stable pavement foundation layers.

The construction of a street never opened to traffic. The extraordinary discovery of pavement engineering in vicolo dei Balconi of Pompeii

A significant portion not yet investigated in the Regio V of the ancient city of Pompeii is currently the subject of the most remarkable excavation in the post-World War II period. These activities relate to a triangular area, the so-called “wedge”, which is placed between the houses of Nozze d'Argento and Marco Lucrezio Frontone. Besides the astonishment and scientific emotions resulting from the finding of magnificent frescoed and well preserved thermopolium, dwellings and balconies, also a feeling of extreme interest in the pavement engineering arose due to a further one of a kind discovery. The Somma-Vesuvium volcanic eruption of 79 AD buried a narrow alley, i.e. vicolo dei Balconi, during the construction of its stone pavement, in which the laying of compact lava stone flags was interrupted about halfway from north to south. The eruption and the following superimposition of lapilli, ash and pumice blankets has therefore maintained in a state of perfect documental conservation the whole area, preserving the new laid flagstones still showing the original surface finishing and the preparatory subgrade. Thus, this historical and archeological source becomes a priceless engineering evidence describing some of the design and construction techniques used by the Romans at Pompeii. The excavated area has been analyzed following a cross-disciplinary approach, adopting several minimally intrusive or non-destructive techniques and instruments belonging to different branches of science to capture some specific aspects. Specifically, the alley has been initially surveyed with a terrestrial laser scanner (TLS) device to build an accurate layout model of the worksite. Although the TLS survey provided an invaluable source of information for the street structures documentation, specific stone paving elements were also analyzed using close range photogrammetry techniques and their friction properties have been measured exploiting the potential of a modern road engineering device, i.e. a skid resistance tester, also known as the British pendulum tester (BPT). The consistency analysis of the subgrade structure and homogeneity in the unpaved section involved the use of two dynamic procedures, i.e. a penetrometric (dynamic cone penetrometer - DCP) and a deflectometric (light weight deflectometer - LWD) test. Besides, some design and urban planning considerations have been drawn from the analysis of the relationships between the finished structures and the pavement construction site according to the lines of the existing curbs, the thresholds of access to the dwellings and the placement of enigmatic prismatic blocks arranged in trenches, probably intended as a useful target points for the stonemasons or temporary pedestrian passage. In a wider reading a succession of paving works (and not repaving) using stone elements in this part of the city starting from the Cardo via del Vesuvio (from west to east) is recognizable.

Laboratory evaluation of an indigenous developed light weight deflectometer as a quality control tool for pavement construction

The mechanistic empirical pavement design concepts are largely based on the theory of elastic layers, and the design is assessed with the characterization of materials used in pavement construction. The present density-based quality assurance (QA) apparatus and its procedures are not effective in measuring the resilient modulus of compacted pavement layers. However, the use of high-cost field apparatus such as nuclear density gauges (NDG) is also encouraging the search for an alternative procedure. This article aims at the measurement of pavement surface modulus directly in the field using a low-cost laboratory developed Indigenous Light Weight Deflectometer (ILWD). The developed ILWDs will be employed for pavement construction QA for interpreting the stiffness of compacted pavement layers. The study was performed on the National Highway-161 in Sivampet, Sangareddy district, Telangana state. The laboratory developed ILWD was validated using the available Light Weight Deflectometer (LWD), Dynatest make, and layer modulus was also computed using a Dynamic Cone Penetrometer (DCP). The DCP was also fabricated in the laboratory as per the Transportation Research Laboratory (TRL), UK. The ILWD and DCP were used to ensure the stiffness characteristics like elastic and dynamic modulus. The field and lab test results indicate that the calculated elastic modulus and stiffness characteristics are close to each other layer moduli for the different pavement layers considered in the study, like sub-grade and granular sub-base (GSB). It is also observed that the test results from the field and laboratory have a good measure of statical correlation among the different stiffness values, and hence the developed ILWD is suitable for pavement compacted layer investigation as quality control.

Prediction of CBR using dynamic cone penetrometer index

Nowadays, construction of new roads and upgradation of existing roads are booming as a part of infrastructural development in India. Subgrade strength plays an important role in the design and construction of pavement. California bearing ratio (CBR) test is used to measure the strength of subgrade and most of the highway agencies design the pavement section using CBR value of the subgrade. The conduction of CBR test consumes more effort and time as it involves soil sampling, preparation of soil specimens, soaking for 96 h and testing. Also, the laboratory assessment of CBR does not simulate the in-situ soil properties (mainly moisture and density) and the laboratory CBR sometimes may be higher than the CBR of the soil under in-situ condition as compaction is carried out in a confined rigid mould. In this study, dynamic cone penetrometer (DCP) index is used to predict the subgrade CBR values. A total of eight soil samples were collected from two different sites and the various engineering properties are determined. To know the effect of density, moisture content, fines content and CBR on the dynamic cone penetration index (DCPI), a series of laboratory compaction tests, CBR tests and DCP tests are conducted. The available correlations are verified for their predictability of CBR values and the correlations suitable for the local soils are recommended.

Evaluation of soil replacement and cement grout injection in soil settlement

This paper discusses the process of original soil stabilization in Trans Sumatra Bakauheni-Terbanggi Besar Toll Road Project Package 2 Sidomulyo-Kotabaru. The soil replacement process was conducted at approximately 24 kilometres along the toll’s main road. The original soil bearing capacity analysis stage was by performing a Dynamic Cone Penetrometer (DCP) and Sondir test to analyze the deep of hard soil. A soil replacement was carried out to replace the original soil with soil that has appropriate specification. the piling up process was conducted in stages, which has Sandstone in such of the layer. The research done about the landfill sample was retaken and collected at 68 points. The stockpile soil samples collection was then followed by the analysis which was conducted in the laboratory to find the soil bearing capacity. There are 4 types of bearing capacity parameters analyzed, namely specific gravity, water content, aggregate analysis (Sieve Analysis), and consistency limit (Atterberg Limit). Referring to it, then there was the classification of soil types according to AASHTO M145 & Casagrande Soil Classification System. A point that has settlement after soil replacement is STA 52+000. So, there need to add soil stabilization, that is cement grout injection. Researchers analyzed the soil settlement by interpretation method. Results showed that soil replacement and cement grout injection could decrease a soil settlement by about 15.07 cm to become 0.93 cm.

Comparison of California Bearing Ratio (CBR) Value Based on Cone Penetration Test (CPT) and Dynamic Cone Penetrometer (DCP)

In civil engineering, land is important because as a place for building infrastructure to be built, so that the building infrastructure on it is stable, adequate carrying capacity is needed. The amount of soil bearing capacity can be determined in several ways, including the California Bearing Ratio (CBR) Field Test, Cone Penetration Test (CPT) and Dynamic Cone Penetrometer (DCP). The CBR and DCP tests are often used to determine the level of surface soil density on road structures, while CPT is usually used to determine the hard soil layer on the building structure. However, in certain situations Sondir and DCP data are often used to predict the CBR value, because the test is quite practical and efficient compared to the CBR test. CBR testing requires heavy equipment which in most small-scale projects is not available. In this study, we compared the CBR value based on the data obtained from the Sondir and DCP tests. Data collection was carried out in Surakarta and its surroundings. Based on the test results, the CBR value generated from the DCP test tends to be smaller than that from the CPT test with a ratio of 0.62: 1. This study resulted in the relationship between CBR values from the results of the CPT and DCP tests shown in the following equation: CBR (DCP) % = 0.2552 CBR(CPT) + 2.6306 and CBR (DCP) % = 0.617 CBR(CPT).

Application of the dynamic cone penetrometer test for determining the geotechnical characteristics of marl soils treated by lime

Quantitative estimation of mechanical characteristics of soils and determination of their behavior using in-situ experiments have always been one of the main concerns of geotechnical engineers. So far, various methods have been introduced to achieve this goal, among which the Dynamic Cone Penetrometer (DCP) test has become more popular as one of the most accurate and efficient methods. Therefore, in this study, an attempt was made to examine the correlation between different soil parameters by performing DCP test along with a series of conventional tests including Unconfined Compressive Strength (UCS) and California Bearing Ratio (CBR) tests on marl soil samples containing 2, 5, 8% lime at 1, 7 and 15 curing days. Furthermore, since the subgrade reaction coefficient (Ks) is needed in the design of pavements and their underlying materials, Plate Load Test (PLT) was performed to determine Ks. The results showed that the addition of lime up to 5% increased UCS, CBR and Ks and decreased dynamic penetrometer index (DPI) of marl soil samples. Further addition of lime had a negative effect on the mechanical characteristics of the samples. Moreover, using the equations obtained from the correlations in this study, strength characteristics and subgrade reaction coefficient of the stabilized marl soil can be estimated by knowing the DPI of the samples. The results of this study showed that the use of the DCP test as a cheap and easy-to-use method can provide a comprehensive view of soil behavior in civil engineering projects with an acceptable coefficient of determination to geotechnical engineers.

Stiffness evaluation of compacted geo-materials using crosshole-type dynamic cone penetrometer (CDP), rPLT, and LFWD

Evaluation of the strength and stiffness of compacted geo-materials is required to ensure that it has sufficient bearing capacity and stiffness to the acting loads. In this study, a crosshole-type dynamic cone penetrometer (CDP) was applied to investigate the strength and stiffness characteristics of a compacted subgrade. The CDP characterizes the subgrade strength by the penetration index (CDPI) and evaluates the stiffness by the shear wave velocity (Vs) and maximum shear modulus (Gmax). CDP tests were conducted at three testing points. Repetitive plate loading tests (rPLTs) and light falling weight deflectometer (LFWD) tests were conducted as standard testing methods for the stiffness estimation of the subgrade. Experimental results show that while the rPLT and LFWD evaluate the equivalent elastic moduli (Ev1, Ev2, and Evd) within the influence zone, the CDP provides the CDPI, Vs, and Gmax along the depth. Linear relationships between the Gmax and the equivalent elastic moduli are constructed. The strain levels corresponding to Ev1, Ev2, and Evd are estimated. This study demonstrates that the CDP is an effective testing method for both strength and stiffness evaluations of the subgrade along the depth.

MONITORING PERFORMANCE OF LATERITE BASE TRIAL SECTION: A CASE OF ADDIS ABABA, ETHIOPIA

This paper is aimed to present an overview of the provision of a demonstration/research trials with particular reference to pavement performance of a laterite base under a double bituminous surface treatment (DBST) as part of a long-term pavement performance (LTPP) monitoring in Ethiopia. The research components were aimed at increasing the use of locally available materials and solving specific problems related to the performance of some roads constructed with thin asphalt seals. In Ethiopia, most roads are built using crushed rock for road base. The project aim was to demonstrate that whether laterite can be used for base course, assess and evaluate the effect of sealed and unsealed shoulder in cut and fill sections. Out of the various field data measurements carried out in each monitoring period (wet and dry season) the paper reviews the in-situ dynamic cone penetrometer (DCP) test results and visual condition assessment observations. It is demonstrated that for such low volume roads laterite base trial sections are performing well, however DCP test results in these sections reveals that the crushed base control sections perform slightly better than the laterite base trial sections and the sections in cut are stronger than in fill while the shoulder sealing doesn’t provide consistent effect on the layer strengths.

Runway Excursions: Bearing Strength Control of Unpaved Areas

The paper deals with the Dynamic Cone Penetrometer application which is intended to work as a vital means to support the bearing strength evaluation over the vast unpaved airport areas. Having identified fundamental drawbacks, the authors proposed some refinements in the original methodology. These predominantly respect the needs of airport operation services. Specifically, the model based on fuzzy logic and two tables, exceptionally suitable for day-to-day applications, are proposed and tested upon the extensive data set acquired at four airports over the last four years.

Subgrade assessment using automated dynamic cone penetrometer to manage geo-infrastructures

For the efficient management of geo-infrastructures in the field, engineering properties of the subgrade should be reliably and rapidly investigated. The objective of this study is to estimate and compare the strength and stiffness parameters of subgrades using portable in-situ devices. An automated dynamic cone penetrometer (ACP), dynamic cone penetrometer (DCP), and light falling weight deflectometer (LFWD) are adopted and applied at nine points of soft ground in South Korea. The Nvalue from the ACP (NACP), which efficiently assesses the relatively deep subgrade, is correlated with the dynamic cone penetration index (DCPI) and dynamic deflection modulus (Evd). Test results show that the DCPI and Evd can be estimated in terms of NACP. In particular, the relationship between Evd and NACP is improved when the strain influence factor of the target ground is considered. For the assessment of strength and stiffness parameters, the California bearing ratio (CBR), relative density (Dr), internal friction angle (φ), and elastic moduli determined by the plate loading test (PLT), soil stiffness gauge (SSG), falling weight deflectometer (FWD) are estimated using NACP. The ACP test with the relationships between engineering parameters and NACP may be an effectively method to assess the overall characteristics of the subgrade.