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The ring penetrometer is a shallow rotational penetrometer that has been developed to characterise the mechanical behaviour of surficial marine sediments. The strain-rate dependency of soils is crucial to the design of a wide range of offshore geotechnical infrastructure founded in the upper layers of the seabed (e.g. pipelines, cables and shallow foundations). This paper explores the potential application of a ring penetrometer test to measure the strain-rate dependency of the interface friction generated in soft soils at low stresses. Large-deformation numerical models of the test are developed using an elastoplastic constitutive model and a viscoplastic variant with strain softening. Using parameters representative of kaolin clay and a calcareous silt from an offshore location, the numerical analyses demonstrate a clear and measurable influence of both the viscous and strain-softening behaviours on the device–soil interface friction. These simulations were used to design suitable experimental protocols for multi-rate ring penetrometer tests, the results of which yielded a strain-rate dependency of 9–16% and 22–26% per log cycle in the kaolin clay and calcareous silt, respectively, which compare favourably with measurements derived from T-bar twitch experiments. Finally, models are presented that can be applied in the interpretation of varying-rate ring penetrometer test data for application in practice. [ABSTRACT FROM AUTHOR]

This study investigates the correlation between the California Bearing Ratio (CBR) and the Dynamic Cone Penetrometer (DCP) for subgrade soil analysis. The paper aims to provide practical equations for predicting CBR values from DCP test results, therefore enhancing the efficiency of soil assessments in engineering practice. By analyzing test data and proposing correlations for different soil groups, the study introduces recalibrated correlations that demonstrate high accuracy in predicting CBR values. The newly proposed equations offer reliable predictions with R 2 values of 0.89, 0.92, and 0.94 for clean sand, silty sand or sandy silt, and cohesive soil, respectively. These correlations serve as valuable tools for engineers, enabling rapid and accurate CBR estimations for improved decision-making in various engineering projects. [ABSTRACT FROM AUTHOR]

Soil classification methods currently rely on soil borings or cone/piezocone penetrometer tests (CPT/CPTu). Literature provides several methods that classify soils based on two parameters (typically tip resistance and friction sleeve/porewater pressure) obtained from CPTu data, defining a soil behavior type. However, these methods face challenges in reliably classifying certain soils, such as organic soils. Robust and complex analyses are required to classify organic soils accurately. In this study, a random forest (RF) based method is developed to predict the presence and depth of organic soils. The RF model utilized features from CPTu soundings including tip resistance, sleeve friction, and pore pressure. The true location of organic soils, derived from index properties obtained from soil borings, served as the model's outputs. Unseen CPTu data was used to predict organic soils throughout the entire project alignment, serving as validation for the model. The model achieved an F1 score of 0.89. Settlement analyses were conducted to evaluate the practical implications of the model's predictions on levee fill costs. The RF-based model yielded settlement predictions that closely matched those obtained through boring predictions. In contrast, traditional classification methods underestimated settlements, resulting in lower estimates for levee fill costs. [ABSTRACT FROM AUTHOR]

Kiwifruit (Actinidia chinensis var. chinensis) firmness is routinely measured in a destructive manner for decision-making purposes. Thus, a population's quality is inferred by measuring a sample from that population. Consequently, studies have investigated non-destructive techniques for measuring fruit firmness. However, most of these studies have been restricted to a single season or focused on performance over long-term storage. This work compared non-destructive compression (1 mm deformation) and acoustic stiffness with flesh firmness measured with a penetrometer across three seasons. 'SunGold' kiwifruit were harvested from 11, 9 and 3 orchards on multiple occasions in 2020, 2021 and 2022, respectively. Kiwifruit was freighted to Palmerston North and assessed on arrival. Thirty fruit per orchard were measured on lab arrival, whilst 24 fruit per orchard were stored for two weeks at 0°C prior to assessment. The non-destructive methods had a strong (r2 > 0.89–0.92) segmented correlation with flesh firmness (0.52–10 kgf). Flesh firmness could be adequately estimated with the non-destructive methods within a season. However, segmented regression performance was reduced when predicting for a season outside of the training population. Nonetheless, these non-destructive methods may be useful for estimating flesh firmness at harvest and after short-term storage (2 weeks at 0 °C). [ABSTRACT FROM AUTHOR]

Field tests are the most suitable method to determine geotechnical parameters. Owing to some restrictions in field tests, physical modeling has been widely accepted as a proper method to define mathematical correlations among geotechnical parameters. This study investigates correlations between parameters derived from cone penetrometer tests. The tests were performed in a cylindrical chamber with a height and diameter of 1000 mm to minimize the boundary effect. Coastal poorly graded sand sampled from the Babolsar region, adjacent to the Caspian Sea, was used. Some correlations among geotechnical parameters, including cone resistance, dynamic cone resistance, dynamic penetration index, modulus of elasticity, internal friction angle, and relative density, are presented. All correlations were categorized into three main categories: soil stiffness, penetration strength, and geotechnical parameters. The results had reasonable accuracy and precision. The average R2 value of the obtained results was approximately 94. The investigations into the inherent CPT also indicated that the strength parameter had more accuracy than stiffness and other sand parameters. Specifically, the R2 value for the correlation between the results of various penetration tests, considered strength parameters, averaged 97. In contrast, the R2 value for the correlation between the elasticity modulus and cone penetration test results was 86. [ABSTRACT FROM AUTHOR]

Free-fall penetration (FFP) testing has drawn wide attention in evaluating in-situ undrained shear-strength (Su) of marine clay because it can save time and reduce costs. However, model parameters for interpreting Su are empirical and usually determined based on engineering experience, leading to great uncertainties in Su results. In this study, FFP model tests were conducted using conical, hemispherical and T-shaped penetrometers to gather data. Subsequently, Bayesian theory was employed to ascertain the optimal model parameters. The penetrometer motion state and influencing factors of penetration depth are analysed and discussed. By considering prior knowledge and inherent variability of Su, optimal model parameters for the three types of penetrometers are obtained using maximum likelihood estimation method. The reasons for the different model parameters of three type penetrometers are discussed. In order to assess the effectiveness of the proposed models, field tests were conducted to gather in-situ data. To reduce uncertainty inherent in limited amount of data, a Bayesian updating approach combined with Markov chain Monte Carlo method were used to evaluate posterior distribution of Su of the three penetrometers. Results show that updated Su samples were consistent with those determined by vane shear tests, which verified the reliability of proposed model parameters. [ABSTRACT FROM AUTHOR]

Dynamic 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. [ABSTRACT FROM AUTHOR]

Viscosity is a fundamental physical property of lava that dictates style and rate of effusive transport. Studies of lava viscosity have predominantly focused on measuring re-melted rocks in the laboratory. While these measurements are well-constrained in temperature, shear rate, and oxygen fugacity, they cannot reproduce the complexities of the natural emplacement environment. Field viscosity measurements of active lava are the only way to fully capture lava's properties, but such measurements are scarce, largely due to a lack of easy-to-use, portable, and accurate measurement devices. Thus, there is a need for developing suitable field instruments to help bolster the understanding of lava. Here, we present a new penetrometer capable of measuring a material's viscosity under the harsh conditions of natural lava emplacement. This device uses a stainless-steel tube with a semi-spherical tip fixed to a load cell that records axial force when pushed into a material, while simultaneously measuring the penetration depth via a free-moving tube that is pushed backward along the penetration tube. The device is portable (1.5 m long, 5.5 kg in weight) and uses a single-board computer for data acquisition. The penetrometer has an operational range from 2.5 × 102 to 2.1 × 105 Pa s and was calibrated for viscosities ranging from 5.0 × 102 to 1.6 × 105 Pa s. It was deployed to the 2023 Litli-Hrútur eruption in Iceland. These field measurements successfully recorded the in situ viscosities of the lava in the range of 1.2 × 104–3.4 × 104 Pa s, showcasing it as an efficient method of measuring natural lava viscosity. [ABSTRACT FROM AUTHOR]

Large deformation finite element simulations of the dynamic penetration of underwater free-fall spherical penetrometers into clay are carried out using the coupled Eulerian–Lagrangian approach. Two undrained total stress analysis models are constructed and applied to simulate four well-documented centrifuge tests of sphere penetration. Model A is a new model that simulates both the free-fall process in water and the penetration process in clay. Model B, as usual, simulates only the penetration process in clay in the absence of overlying water. The simulation of the free-fall process in water is validated against an analytical solution and calibrated against the measured impact velocities of the tested spheres upon hitting the clay surface. The ability of the two models to predict the dynamic penetration behavior in clay is evaluated by comparing their results with the centrifuge test results. Model A provides a better prediction of the penetration behavior than Model B. Fully open, partially closed, and fully closed cavities formed by the passages of the sphere and water were reproduced by Model A. The water flow in the wake of the penetrating sphere is shown to have an important influence on the deformations of the clay surface and cavity wall. [ABSTRACT FROM AUTHOR]

In-situ tests for predicting geotechnical parameters related to shear strength, such as California Bearing Ratio (CBR), typically require drilling boreholes and manual cone driving, which can be timeconsuming, expensive, and labor-intensive. The Dynamic Cone Penetrometer Test (DCPT) has emerged as a simpler, faster, and less expensive alternative for predicting CBR and other geotechnical parameters. This systematic review uses Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines to examine relevant literature on DCP testing for accurately predicting CBR and other geotechnical parameters. After trimming 111 relevant studies to 55, the review discusses various research questions, including the correlation between DCP and CBR, factors such as water content and seasonal variations, and recent advances in DCP testing. The review emphasizes the importance of considering unsaturated soil behavior, such as soil suction, in pavement subgrade design to ensure the longevity and quality of the pavement. The findings provide compelling evidence for the utilization of DCP testing as an essential tool for predicting geotechnical parameters and designing high-performance pavements. By demonstrating the DCPT's remarkable convenience, reliability, and cost-effectiveness in CBR and geotechnical parameter prediction, this study paves the way for significant advancements in pavement design efficiency and economic viability. [ABSTRACT FROM AUTHOR]

Pressure Probe (PreP) is in effect a simplified penetrometer: it measures the mechanical resistivity of the soil at shallow depths dropping the probe always from the same height. The resolution of this technique is very good. It is able to detect e.g., fractures due to their decreased mechanical resistance if they are covered, but in a shallow depth with a reasonable sampling distance. An example will be demonstrated where fracture system of a slowly-moving landslide was characterized enabling also its delineation. In spite of that its maximal penetration is only about 0.5 m it may also give information from remarkable depths in case if fractures reach close to the surface indicating the borders of geological structures in larger depth. An example from India will be shown to present such results. All results have been verified by geoelectric measurements. PreP may also indicate any kind of hidden holes indirectly. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

In the past few years, offshore site investigations have extensively utilized full-flow penetrometers like the Ball and T-bar penetrometers to assess penetration resistance and subsequently analyze the strength characteristics of marine clay. The relationship between penetration rate and the measured resistance to penetration and shear strength in clays has been extensively documented through full-flow penetration tests. Although previous studies have shown empirical correlations between undrained shear strength and penetration resistance, the resistance factor utilized in these correlations is typically suggested for cohesive soils that are overconsolidated or normally consolidated, rather than underconsolidated soils. The effects of penetration rate undrained penetration resistances in underconsolidated marine clay are investigated in this study by considering the outcomes of variable rate penetration testing and twitch penetration testing using full-flow penetrometers in laboratory model tests. The discussion focuses on penetration resistances depending on the normalized velocity of the full-flow penetrometers (Ball and T-bar). [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

• Presentation of a method to assess soil compaction in the agriculture field. • The greatest soil compaction occurred at the highest wheel load (1000 N), the lowest speed (0.1 m/s) and the highest number of passes (third pass). • Minimise multiple passes and otherwise follow the same path. • Keep the load on the ground as low as possible (weight of the machines); • Work at high speed in agricultural fields. Soil compaction is one of the major problems in modern agriculture. Thus, the workability of a soil reflects to its ability to accept the traffic of agricultural machinery and implements. Water content and compaction are factors that influence the rheological behavior of the soil. the representation of soil shows limitations regarding the behavior of the tire-soil interface and its resistance to deformation is both influenced by the different forms of loading application along a tire path on a soil particle. This paper presents a study of the impact of multiple wheel passage, the wheel velocity, and the weight applied to the wheel on the agricultural soil represented by the cone index. To do this, we were inspired to launch an investigation for soil compaction determination at three levels of wheel load, three levels of velocity and at tillage, first, second and third passages of wheel with three replications on clayey sandy mixed grain soil. The results of this study shows that the greatest soil compaction occurred at the highest wheel load (1000 N), the lowest speed (0.1 m/s) and the highest number of passes (third pass), this leads to minimize multiple passes and or follow the same path, also, keeping the load on the ground as low as possible (weight of the machines), and working at high speed in agricultural fields. [ABSTRACT FROM AUTHOR]

The bounce and penetrometer resistance (PR) of a cricket pitch for three different crack-control conditions was investigated. In total, 15 miniature cricket pitches were prepared using the conventional procedure, natural grass roots and geotextile roofing felts combined with varying proportions of fine sand and bentonite clay. The rebound ball height and ground PRs were measured with a designed bounce meter and pocket penetrometer, respectively. The properties of the pitch soils (e.g. crack width, moisture content and field densities) were also measured. The results of the test programme indicated that the pitch with the geotextile crack-control system provided a higher coefficient of restitution (CoR) and PR than the other two systems. The test results also suggested that, in order to reduce significant growth of crack widths to provide a good cricket pitch, the clay content under geotextile roofing felt should be kept at 50–65%. Several equations relating the CoR and PR with crack width and the physical properties of the pitch soil were developed for use in pitch characterisation. [ABSTRACT FROM AUTHOR]

Underwater track vehicles (UTVs) will penetrate and shear the soil while walking on the seabed. The penetration reflects the soil's strength, and the shearing determines the traction that the soil can provide. The traditional bevameter technique for simulating the above processes comprises two separate tests, a plate penetration test, and a shear test. However, the effect of grousers and the connection between the two processes are ignored by the bevameter technique. Here, a novel penetrometer is proposed to simulate track-soil interaction, combining penetration and shearing into continuous compression and torsion. Numerical simulations and model tests were used to evaluate the feasibility and validity of the novel penetrometer concept. In the numerical simulations, compared with the traditional method, the pressure of the new method was increased by about 20% because of the effect of grousers, and the peak shear stress was increased by about 10% because of the continuous simulations. In the model experiments, the corresponding increases were about 25% for the pressure and 28% for the peak shear stress. The results show that the novel penetrometer can better simulate the continuous processes of UTVs, and its tooth structure reflects the grousers' effect. [ABSTRACT FROM AUTHOR]

The ball penetrometer is a full-flow penetrometer used as an alternative to the traditional cone penetrometer for characterizing the strength of soft sediments, particularly for offshore engineering, due to its large projection area. However, if the ball is penetrated under partially drained conditions, the resistance of the ball changes with the penetration velocity. The performance of ball penetration is examined employing a coupled large-deformation finite-element method. The reliability of numerical simulations under undrained and partially drained penetrations is verified by comparing with previous tests in the chamber and centrifuge. The backbone curve determining the penetration resistance on the spherical probe is proposed to quantify the influence of partially drained conditions, which captures the effect of the ratio of the diameters of the shaft and ball. Base on the backbone curve derived, an interpretation approach is proposed to predict the effective internal friction angle using the net resistance measured in the ball penetration tests with different penetration velocities. [ABSTRACT FROM AUTHOR]

In the context of the problem of insufficient consumption of fish products, the possibility of creating high-quality sausage products based on new types of raw materials is considered. The development of high-quality fish sausages from new raw materials will expand the range of sausage products and provide the population with seafood products. The purpose of the study is to establish the feasibility of using African sharptooth catfish in the technology of fish sausage products. The study used a complex of generally accepted organoleptic, chemical, physico-chemical methods of research: moisture content - by drying the sample to a constant weight; fat content - by the Soxhlet method; protein content - by the Kjeldahl method; ash - by burning the sample. The penetration stress was determined using a penetrometer; water activity index - using a hygrometer; the hydrogen index - using a pH meter. As a result of research, the feasibility of using the African sharptooth catfish as a raw material for making fish sausages is theoretically substantiated and experimentally confirmed (Clarias gariepinus Burchell, 1822). The effectiveness of combining catfish meat with other hydrobionts and animal raw materials is shown. New recipes for raw smoked sausages based on African catfish with the addition of mackerel, scallop, and lard have been developed. Organoleptic and physico-chemical indicators of quality and nutritional value of finished products were studied. The results of organoleptic evaluation showed the similarity of catfish sausages to conventional meat sausages. Fish flavour and aroma were poorly expressed in sample 2, which included only African catfish meat from fish raw materials, which determined its consumer preferences. Sample 3 obtained by combining African catfish meat with mackerel and scallop received high organoleptic scores. The results of a study of the chemical composition show a high nutritional value of sausage products based on the improved recipe. The moisture content in all samples did not exceed 50%, which is the standard for raw smoked sausages. The highest protein content (26.19%) was observed in sample 2, the amount of protein in other sausage samples exceeded the minimum recommended value of 19%. The fat content in all samples was in the range of 18.93-21.41%, which does not exceed the recommended standard of 25%. Based on the results of physical and chemical studies, the indicators were found to be in line with the established standards. Studies of changes in quality and safety indicators during storage determined the permissible shelf life of raw smoked fish sausages at temperatures from 0 to +5°C for no more than 15 days [ABSTRACT FROM AUTHOR]

This study investigates the geotechnical characteristics of a soft tidal mudflat in the Great Bay Estuary, New Hampshire. Laboratory testing of surficial sediment samples of the upper 10 cm and field observations from a portable free-fall penetrometer (PFFP) were used to characterize soil strength properties (coefficient of consolidation and undrained shear strength). Pore pressure measurements from the PFFP were analyzed using a square-root of time method to estimate t50 and empirical correlations from the literature to estimate the coefficient of consolidation. Undrained shear strengths were estimated from the PFFP deceleration using cone factors of 10–12 and a strain rate correction factor of 0, resulting in undrained shear strengths of 0.5–1.1 kPa. Laboratory testing using miniature vane shear testing found the undrained shear strength to be 0.6–1.8 kPa. Both techniques indicate soft soils. The PFFP deceleration profiles also suggest the presence of layering within the seabed, a situation at the field site that could arise from environmental factors, such as winter ice formation and seasonal erosion. The coefficients of horizontal consolidation estimated with the PFFP (5.4×10−6–1.7×10−5 m2/s) were 1–2 orders of magnitude greater than the coefficients of vertical consolidation measured during oedometer testing (9.51×10−8−1.78×10−6 m2/s across all samples and load steps). Effects impacting the coefficient of consolidation such as to mismatches between sample depths and the resting depth of the penetrometer, sample disturbance, anisotropy, differences in loading conditions, and limitations associated with deriving values from literature charts are discussed. The results suggest that PFFPs are able to well-characterize the geotechnical properties of tidal mudflat soils and contribute to improving the understanding of the geotechnical parameters of undrained shear strength and coefficients of consolidation. [ABSTRACT FROM AUTHOR]

Simple Summary: The purpose of this study is to investigate the potential of using simple, portable tools to conduct surface condition measurements on race days at turfgrass Thoroughbred racetracks to approximate the biomechanical measurements made prior to the race meet. Test plot measurements were conducted with these tools as well as a more complex biomechanical device which replicates the speeds and loads of a Thoroughbred at a gallop. The turf plots were chosen to simulate a wide range of potential turf profiles that could be used in North American racetracks. The correlations were investigated and linear regression models were constructed to determine the level of approximation the simpler tools might achieve with the range of profiles considered. The volumetric moisture content was found to be the primary simple daily measurement which correlates to biomechanically based measurements. The penetration from the Longchamp Penetrometer and surface hardness from the Clegg Impact Hammer can further improve the approximation to equine biomechanics if desired. As this data are collected on a larger scale, it can then be paired with race times and injuries to investigate potential links between these measurements and horse performance and risk of injury. Both pre-race meet and daily turf surface condition measurements are required by regulations adopted as part of the Horseracing Integrity and Safety Act (HISA). The Orono Biomechanical Surface Tester (OBST) is the primary device used for characterizing a racing surface and is used for the pre-meet inspections. Tools that are better suited for the daily testing of turf surfaces are also needed to meet the new federal regulations. The purpose of this study was to compare five simple tools commonly used in turf applications to the OBST. Data were collected with each of the six devices at plots chosen to approximate the current and potential compositions of North American turf racetracks. Correlations and linear regression models were then established between the simple tool measurements and the parameters measured by the OBST. The moisture probe was found to be the primary device for race day characterization due to its strong correlation to OBST measurements. The Longchamp Penetrometer is also prioritized for daily measurements due to its established correlation to horse performance and injuries. The Clegg Impact Hammer provides further improvement of the linear regression model. The Turf Shear Tester and GoingStick® were not found to correlate well to the biomechanically based device. [ABSTRACT FROM AUTHOR]

Hand-pushed cone penetrometer has been utilized to assess soil compaction based on soil penetration resistance (SPR). However, the manual operation of these devices can be quite challenging and erroneous. The accuracy of the data gathered using such devices can be hindered by the operator's limitation in maintaining a constant-rate of penetration into the soil, thus preventing the attainment of a steady, predefined penetration rate. To address this issue, a constant-rate, IoT-enabled cone penetrometer is designed and constructed. The developed penetrometer measures the SPR across the soil profile with a designed lead screw arrangement that ensures a constant-rate penetration. The device comprises a mechanical system and an electronic control unit that utilizes IoT framework. The mechanical system includes a primary frame, lead screw arrangement and a standard penetrometer probe. The SPR, and depth along with coordinates of location are measured and stored on a web server. A user-friendly customizable web interface and mobile application enable real-time access. The developed penetrometer measures the SPR up to 2000 kPa up to 400 mm depth. Comparative analysis shows that the constant-rate penetrometer (CRP) provides more reliable and less variable resistance measurements compared to the hand-pushed penetrometer (HPP), with significant differences observed at multiple depths. This penetrometer maintains a constant-rate of penetration, ensuring adherence to predefined standards for accurate measurements. [ABSTRACT FROM AUTHOR]

The strength of lateritic soil bio-treated with a Bacillus thuringiensis (Bt)-induced calcite precipitate was investigated using a pocket penetrometer (PPT). The effect of bacterial (Bt) and cementation solution concentration (Cs) on the strength of the microbial-induced calcite precipitate (MICP) worked soil was also evaluated. Soil samples were treated with Bt and Cs using three mix ratios (i.e., 25% Bt: 75% Cs, 50% Bt: 50% Cs, and 75% Bt: 25% Cs) based on the natural soil liquid limit (LL = 36.0%). Bt suspension densities of 0, 1.5 × 108, 6.0 × 108, 1.2 × 109, 1.8 × 109, and 2.4 × 109 cells/mL were applied to the soil with four varying Cs concentrations (i.e., 0.25, 0.5, 0.75, and 1 M). The prepared specimens were allowed to homogenise and equilibrate at laboratory conditions. A pocket penetrometer (PPT) was used to test the unconfined compressive strength (UCS) of the prepared specimens at 3, 5, and 7 days after bio-treatment to evaluate the strength of the MICP worked soil at different moisture contents. The results obtained show that the UCS values increased with higher Bt and Cs as well as with a reduction in moisture content as the bio-treated soil equilibrated with the environment. The recorded UCS values for the mix ratios considered were in the order: 50% Bt: 50% Cs > 25% Bt: 75% Cs > 75% Bt: 25% Cs. Therefore, a PPT can be used to determine the approximate unconfined compressive strength of treated soil. [ABSTRACT FROM AUTHOR]

• Useful for studying soil compaction induced by vehicular or machinery traffic. • Sensing unit comprises a load cell (S-type) and an ultrasonic sensor (HC-SR04). • Capacity: soil penetration resistance − 5000 kPa and penetration depth − 500 mm. • Sensor characteristics: accuracy, sensitivity, non-linearity and non-repeatability. • Faster data collection, easy-to-use Android-based mobile application, and low cost. Measurement of soil compaction in terms of penetration resistance using a hand penetrometer requires more time and effort. A tractor hydraulic-assisted embedded microprocessor-based penetrometer was developed to make the results easy to monitor and decrease human error. The developed penetrometer consisted of a driving system for pushing the penetrometer probe into the soil at a desired speed, a sensor unit (load cell and ultrasonic sensor) for measuring the force required to push the probe and the depth of penetration, and a data logging system. The embedded system of the penetrometer comprised various components: Arduino Uno microcontroller, I2C, WiFi module, and HX711 amplifier. The system was able to measure a soil penetration resistance of 5000 kPa up to a depth of 500 mm. A WiFi module helped to transmit the data to an Android mobile application. The acquired data also include date/time parameters along with latitude and longitude locations picked up from the GPS of the mobile. Its performance was assessed based on sensor characteristics such as accuracy, sensitivity, non-linearity, and non-repeatability. The average and maximum absolute variations in the cone index values measured with developed system and a hand-held digital penetrometer were observed to be 22.50% and 27.88%, respectively. [ABSTRACT FROM AUTHOR]

CPT is a geotechnical investigation method that, depending on the geology, has been proved to be an essential tool to establish the Geotechnical Design Model. However, doubt has been raised about the quality of the data. Hence, the feasibility to use data from CPT to evaluate reliable parameters for the Geotechnical Design Model also needs investigation. Currently, the international standard EN ISO 22476-1 [1] is being revised, and the revised version will be published in winter 2022. It will include new requirements related to quality parameters such as zero stability, zero-shift, temperature, and pore pressure response. In addition, there will be updated requirements related to the calibration of the cone penetrometer. All this is to improve the quality of the CPT data, thereby increasing the reliability of parameters evaluated from CPT. This paper presents a feasibility study. It compares the zero-shift variation depending on the type of cone penetrometer, the operator, and the geology. More than 2 500 soundings from Sweden, Norway and Finland were the basis for this comparison. The results indicate that the data quality is strongly linked to the type of cone penetrometer, its calibration, and the management of the cone penetrometer in the field. [ABSTRACT FROM AUTHOR]

Identifying the precise elevation of the seabed is important for many applications, including navigation and the investigation of seabed surface processes such as erosion and scour. Certain sediment conditions, such as fluid mud or very soft soils with high water content, can challenge the accuracy and consistency of seabed or mudline identification. Portable free-fall penetrometers (PFFPs) can assist with determining the mudline; however, this is typically done during processing by an expert user, leading to possible uncertainties and bias. The determined mudline location also affects PFFP processing such as zero-offsetting to account for water column effects as well as the determined penetration depth. In this work, an automated methodology is proposed to reliably predict the impact point. The method's performance is compared with human processors. The proposed method shows good agreement with human processors for soil with fines content less than 50% and undrained strengths greater than 1.5 kPa. At higher fines content and lower undrained strength, the automation identified the mudline generally later and at a greater depth, representing a more conservative but less ambiguous choice. [ABSTRACT FROM AUTHOR]

Coastal environments are characterized by a variety of sediment deposits with highly diverse geotechnical properties. Particularly in energetic coastal environments, sediment type and properties may vary on small spatiotemporal scales, limited previous information may be available, and sediment coring may be difficult. This study proposes a single data analysis framework to estimate geotechnical strength parameters in the uppermost layers of the seabed surface for a wide variety of sediment types from portable free fall penetrometer (PFFP) measurements without need for previous or complementary data. The framework builds on existing approaches and modifies and integrates them toward one universal analysis procedure. Target results are to distinguish sediment type, estimate relative density and critical friction angle for coarse-grained sediments, and undrained shear strength for fine-grained sediments. Data sets and sediment samples collected from seven different sites across the US served the validation and assessment of the framework. It was found that for the PFFP used a penetration depth less than 20 cm indicated coarse-grained sediments with a certainty of 96%, whereas a penetration depth greater than 25 cm was associated with fine-grained sediments with a certainty of 100%. Friction angles yielded a favorable match with laboratory triaxial and direct shear testing for the sand within ±1° and undrained shear strength values resulted in mismatches <10% of minivane shear results for most fine-grained sediments using cone factor of 10 for two groups of sediment strength-depth profiles. Higher mismatches observed for the third type of distinct profiles (up to 48%) suggested lower cone factors, likely related to a change in sediment properties. This paper proposes a single framework that builds on and evaluates existing approaches to estimate geotechnical sediment properties in coastal environments using a portable free fall penetrometer. The framework identifies different soil types (coarse-grained versus fine-grained) and proceeds with data analysis toward strength parameters. Relative density and friction angle are estimated for coarse-grained sediments, and undrained shear strength is estimated for fine-grained sediments. Results of the framework were validated and assessed with laboratory testing based on a data set collected from over seven different sites across the US. The good agreement between field and lab results supports the feasibility for one data analysis framework for the use of portable free fall penetrometers for a rapid and preliminary seabed surface characterization, especially in areas with difficult access or under extreme conditions. This makes this method accessible to a broad group of users in the geotechnical and coastal engineering community. [ABSTRACT FROM AUTHOR]

The dynamic probing test is effective for compaction control in road embankments and pavement layers. However, challenges exist to its use in dense soil types to obtain valid results. The main purpose of this research is to use light weight penetrometer in dense soils and obtain valid results. This study developed and tested three light dynamic penetrometers with different cone geometries in dense soils and compared their results with those of conventional dynamic penetrometers. Over 72 dynamic penetration tests were performed in the field in dense natural soil. The results showed a 50% reduction in the number of blows compared to the dynamic probing light penetrometer (DPL). The coefficients of variation of the results of 8.6% to 15.9% indicate desirable repeatability. To further evaluate the efficiency of these penetrometers, the correlations between their results and the soil characteristics of the dry unit weight in place, compaction percentage and peak shear strength were assessed by statistical residual analysis. This approach showed that these relationships were satisfactory. [ABSTRACT FROM AUTHOR]

Background: Sugarcane (Saccharum spp.) is the core crop for sugar and bioethanol production over the world. A major problem in sugarcane production is stalk lodging due to weak mechanical strength. Rind penetrometer resistance (RPR) and breaking force are two kinds of regular parameters for mechanical strength characterization. However, due to the lack of efficient methods for determining RPR and breaking force in sugarcane, genetic approaches for improving these traits are generally limited. This study was designed to use near-infrared spectroscopy (NIRS) calibration assay to accurately assess mechanical strength on a high-throughput basis for the first time. Results: Based on well-established laboratory measurements of sugarcane stalk internodes collected in the years 2019 and 2020, considerable variations in RPR and breaking force were observed in the stalk internodes. Following a standard NIRS calibration process, two online models were obtained with a high coefficient of determination (R2) and the ratio of prediction to deviation (RPD) values during calibration, internal cross-validation, and external validation. Remarkably, the equation for RPR exhibited R2 and RPD values as high as 0.997 and 17.70, as well as showing relatively low root mean square error values at 0.44 N mm−2 during global modeling, demonstrating excellent predictive performance. Conclusions: This study delivered a successful attempt for rapid and precise prediction of rind penetrometer resistance and breaking force in sugarcane stalk by NIRS assay. These established models can be used to improve phenotyping jobs for sugarcane germplasm on a large scale. [ABSTRACT FROM AUTHOR]

The density, temperature, and punch head velocity are dominant factors to the variation of the compacted snow hardness measured by penetrometers. This effect is essential to the construction and operation of compacted snow roads. The Improved Motor-driven Snow Penetrometers (IMSP) are utilized in this research to control the penetration speed and measure the true cone hardness during snow penetration. This study employs a multi-method approach combining orthogonal experiments and the Support Vector Regression (SVR) technique to analyze the effects of these three factors on snow hardness. The results of this investigation indicate that, under identical conditions, density is positively correlated with the hardness of compacted snow, and its sensitivity and significance to the compacted snow hardness are the greatest. Temperature and penetration speed have an effect on hardness, which cannot be completely ignored. The hardness of snow close to its melting point, regardless of its density, decreases significantly at high penetration rates. This study investigates the factors that influence the hardness of compacted snow and provides substantial technical support for the design, construction, and maintenance of snow roads. [ABSTRACT FROM AUTHOR]

Resilient modulus (Mr) is one of the crucial parameters, which is used for the design of a multilayer pavement system. The Mr is defined as a ratio between deviatoric cyclic axial stress to the recoverable axial strain. In general, the Mr is measured through the cyclic triaxial compression test. Besides, other tests such as light weight deflectometer (LWD) and dynamic cone penetrometer (DCP) were also employed to calculate the Mr of subgrade soil. In this study, two types of soil in Vietnam were taken and used for determining the Mr in the laboratory. Two field tests (i.e LWD and DCP) were also implemented for comparison. The results of this study show that the Mr of soil was positively related to compaction degree and confining pressure regardless of soil type. However, the changes of the Mrs under different deviator stresses varied with the type of subgrade soil. The Mr increased with the greater deviator stress for the two types of soil. Furthermore, the field LWD testing method can be effectively utilized to determine the resilient moduli of soil samples tested under similar conditions with a high level of accuracy. Finally, it was found that the dynamic penetration index has a good relationship with the dynamic deformation modulus. This correlation may thus yield a satisfactory estimation with an appropriate coefficient of determination. [ABSTRACT FROM AUTHOR]

Robotic solutions and technological advances for turf management demonstrated excellent results in terms of quality, energy, and time consumption. Two battery-powered autonomous mowers (2 WD and 4 WD) with random patterns were evaluated according to different trampling levels (control, low, medium, high) on a typical warm season turfgrass at the DAFE, University of Pisa, Italy. Data on the percentage of area mowed, the distance traveled, the number of passages, and the number of intersections were collected through RTK devices and processed by a custom-built software (1.8.0.0). The main quality parameters of the turfgrass were also analyzed by visual and instrumental assessments. Soil penetration resistance was measured through a digital penetrometer. The efficiency significantly decreased as the trampling level increased (from 0.29 to 0.11). The over-trampled areas were mainly detected by the edges (on average for the medium level: 18 passages for the edges vs. 14 in the central area). The trampling activity caused a reduction in turf height (from about 2.2 cm to about 1.5 cm). The energy consumption was low and varied from 0.0047 to 0.048 kWh per cutting session. Results from this trial demonstrated suitable quality for a residential turf of the Mediterranean area (NDVI values from 0.5 to 0.6), despite the over-trampling activity. Soil penetration data were low due to the reduced weight of the machines, but slightly higher for the 4 WD model (at 5 cm of depth, about 802 kPa vs. 670 kPa). [ABSTRACT FROM AUTHOR]

• Novel flexible penetrometer for planetary regolith exploration is proposed. • Penetration model analysis and validation were conducted. • Principle prototype of the penetrator was developed and the system was verified. In-situ extraction of geological information from planetary subsurfaces is of great importance. To achieve this goal with low power consumption and deep penetration, a novel subsurface sounding system for planetary regolith exploration is proposed based on the operating principle of tape measures. Penetration model analysis and validation were conducted. The penetration mechanics of the penetrator head and body were modeled separately, and static penetration tests were performed to verify the feasibility of the penetrator and modify the penetration load model. As the structural design of the penetrator was completed, a cam-based impact clamping scheme was proposed. The impact system dynamics model was established to analyze the effect of pene-tration resistance and kinetic parameters on the penetration capability of the penetrator. The principle prototype of the penetrator was developed, and a load-free simulated planetary regolith penetration test system was built to verify the correctness of the design. This study may provide technical support for the future application of flexible detectors in planetary exploration. [ABSTRACT FROM AUTHOR]

In recent years, the development of marine hydrocarbon resources has led to an increased demand for research on the marine soil bearing capacity and cyclic loading effect in marine engineering design. Because of the difficulties and high costs involved in obtaining high-quality soil samples from offshore sites, in situ testing techniques have become the preferred method of determining design parameters in offshore geotechnical engineering projects. This paper provides a review of the current state of marine penetrometer deployment technology used in offshore engineering investigations and presents a summary of the T-bar penetrometer test for measuring marine soft clay. The existing literature research on penetration mechanisms, numerical simulations, laboratory experiments, and field tests of the T-bar penetrometer in the field of marine geotechnical engineering are analyzed. Finally, the potential difficulties, challenges, and prospects of the T-bar penetrometer tests are discussed. [ABSTRACT FROM AUTHOR]

This paper provides a five-year performance evaluation of an application of geogrid reinforcement in low-volume unpaved roads using dynamic cone penetrometer (DCP), plate load tests (PLT), and roadway sensing method. A Forest Service unpaved road located in northern Arizona, USA, exhibited severe deterioration on the surface, creating an unsafe traffic environment for vehicles. A total of four structural sections (1–4; 4.3 m wide) were installed in the 40 m long test area. One additional section of existing subgrade/roadbed with native soil adjacent to the test sections was used for comparison purposes. The project was originally completed in November 2015, followed by five annual field visits to observe surface conditions of the five test sections. Based on DCP and PLT results (both conducted in 2015), and roadway sensing tests conducted in 2020, the section made of 30 cm thick aggregate with one geogrid layer appeared to have a better capacity for resisting traffic loading as compared with the other four sections. This paper concludes that, from a long-term point of view, the geogrid reinforcement improves the capacity of the unpaved roads, with significantly reduced rutting and damage from both roadway traffic loads and weathering effects. [ABSTRACT FROM AUTHOR]

Predicting spudcan penetration is essential for reducing risk during the installation of an offshore mobile jack-up platform. However, predictions made prior to installation often deviate from those recorded in practice, mainly because inherent uncertainties in seabed soils are not adequately considered. In this paper, the characteristics of the seabed are quantified using monitored spudcan installation data by developing a Bayesian framework coupled with Metropolis algorithm-based Markov chain Monte Carlo (MCMC) simulation. Applied to sand overlying clay conditions multiple readings from the load–penetration curve are used to derive statistical interpretations of seabed parameters such as sand thickness, sand friction angle and the undrained shear strength profile of clay. Illustrative examples demonstrate the proposed method using data from geotechnical centrifuge tests and a monitored offshore jack-up. The accuracy of the method is also retrospectively examined against a database of 66 centrifuge tests. The results show that the proposed method can provide consistent soil parameters with reduced uncertainty regardless of the influence of the updating sequence, number of MCMC chains, scale factors and the prior distributions applied. This method offers the offshore industry a new methodology to statistically interpret seabed conditions by incorporating monitored data. Potentially it could be combined with spatial interpolation methods to infer ground conditions and more accurately predict future spudcan installations. [ABSTRACT FROM AUTHOR]

Soil is the habitat for soil organisms and associated soil physical and chemical processes. The subsoil is a large reserve of water and nutrients. Soil and subsoil are thus significantly involved in the yield capacity of a site and its resilience in the case of unfavorable weather conditions. Subsoil can also retain water in drought phases and stores carbon. In times of climate change and scarcity of resources, many scientific activities involve subsoil and require sensors to assess subsoil conditions and properties. An electrically driven penetrometer with an integrated soil water content sensor could be an appropriate tool for such applications; however, such a subsoil measurement tool does not exist. One major reason for this is that, when penetrating compacted subsoil, high penetration forces (including friction) act on the penetrating thin rod (diameter 1 cm). The development of a tractor-mounted subsoil penetrometer for depths up to 2 m is described in this study. An ASABE standard cone is implemented, which can access heavy compacted layers. The rod, which includes wires for embedding an FDI moisture sensor in the cone tip, is covered by a protection tube. The penetration resistance measurement can be performed without being influenced by shaft friction. The rod, along with the sensor, is implemented in a tower that can be shifted laterally and can take probes in a single line without moving the tractor. To confirm the quality of the developed subsoil penetrometer, a suitable evaluation method is presented. Typical arable soil (loamy silt) was filled in boxes and compacted homogeneously using a hydraulic stamp so that different setups of the penetrometer could be compared and evaluated. The evaluation concludes that the distance between the free cone tip and the protection shaft should be at least 10 cm to measure the penetration resistance of soil without being influenced by the protection tube. Furthermore, the developed penetrometer has sufficient stability and precision for accessing subsoil. In field trials, the subsoil penetrometer was compared with a standard penetrometer and has proved its suitability. [ABSTRACT FROM AUTHOR]

The tip shape of penetrometers and piles has an important influence on the soil resistance mobilized during penetration. Blunt or flat tips typically generate greater penetration resistances, which can lead to refusal during in-situ testing and pile driving in the field. Results are presented from numerical and experimental investigations on probes with conical tips of varying apex angles to quantify the effect of the apex angle on the mobilized penetration resistance and associated failure mechanisms. Discrete element modeling (DEM) simulations were performed in unconfined and confined (i.e., stress-controlled) specimens to model shallow and deep penetration conditions, respectively. Centrifuge penetration tests were performed by quasi-statically advancing an instrumented probe to a depth-to-probe-diameter ratio of 16.7. The numerical and experimental results indicate that at shallow depths, the sharper tips mobilize smaller penetration resistances. In deep penetration conditions, the changes in penetration resistance with tip apex angle are less pronounced. Based on the results of the two investigations and values reported in the literature, a relationship characterizing the functional form between tip apex angle and normalized penetration resistance is proposed. A mesoscale analysis of the DEM simulation shows differences in the failure mechanisms induced by sharp and blunt tips: the zone where large particle displacements and stress changes occur is large and located below the tip for penetration with blunt tips, whereas the zone is smaller and located both laterally and below the tip for sharp tips. [ABSTRACT FROM AUTHOR]

The uniqueness of the Carpathian Mountain Forest ecosystems, a large part of which belongs to nature conservation areas, attracts a significant number of visitors annually. Intensive tourist flow on popular hiking trails leads to recreational digression, topsoil compaction, development of erosion processes and deterioration of forests. The research aims to determine the impact of recreation as an external mechanical impact on soil compaction by determining the soil penetration resistance under the canopy of predominant spruce stands. For this purpose, soil penetration resistance was measured with a penetrometer along two hiking trails within the root layer of the soil at four measuring sites at different distances from the hiking trail. In general, under the canopy of a forest stand, the soil cover is not homogeneous and the obtained penetration resistance values are characterised by considerable variability. It was revealed that for the “Zelene village – Uhorski skeli rocks” hiking trail in the areas close to the path (up to 20 m) there is a significant increase in soil penetration resistance compared to remote areas: at a depth of 10 cm itdoubles, at a depth of 20 cm – by 20-40%, but with further deepening, the penetration resistance level off. At the same time, for the more popular “To Mount Pip Ivan Chornohirskyi” hiking trail, in the area adjacent to the trailbed, the penetration resistance reaches 19.6 kg·cm-2 in the upper 10 cm layer, and at a depth of 30 cm, it peaks at 37.8 kg·cm-2 (over 3 MPa), which affects the root spatial distribution of spruce forests. Intensive erosion processes due to soil compaction with an increase in soil penetration resistance above 60 kg·cm-2 (~6 MPa) are observed on the trailbed. The practical significance of the results obtained, and the established patterns is to complement existing methods for assessing the degree of recreational digression in mountainous conditions and can be the basis for designing measures to regulate tourist flows and restore affected areas. [ABSTRACT FROM AUTHOR]

A procedure for estimating reliable ranges of Nkt for direct simple shear (DSS)-based and anisotropically consolidated triaxial compression (CAUC)-based undrained shear strength is presented. The procedure is based on a combination of three Normalized Soil Parameter (NSP) methods and two CPTu (piezocone penetrometer) methods and are related to the ratio of net cone resistance to hydrostatic effective vertical stress. The NSP and CPTu data used were acquired from seven sites: these sites have stress histories ranging from very underconsolidated to very highly overconsolidated. The stratigraphies of the seven sites consist of clays that are moderately plastic to highly plastic. This proposed procedure was then applied to 22 published sites with a wide range of fine-grained soil types and index properties. The procedure yielded very consistent and reasonable envelopes of Nkt, which in turn, provide sound DSS-based strength profiles as well as CAUC-based strength profiles. The proposed procedure also clearly demonstrates that the range for Nkt factors is not limited to 15 to 20 for normally consolidated to lightly overconsolidated cohesive sediments, which is frequently employed by practitioners. [ABSTRACT FROM AUTHOR]

Snow-layer segmentation and classification is an essential diagnostic task for a wide variety of cryospheric applications. The SnowMicroPen (SMP) measures the snowpack's penetration force at submillimetre resolution against the snow depth. The resulting depth-force profile can be parameterized for density and specific surface area. However, no information on traditional snow types is currently extracted automatically. The labeling of snow types is a time-intensive task that requires practice and becomes infeasible for large datasets. Previous work showed that automated segmentation and classification is in theory possible, but can either not be applied to data straight from the field or needs additional time-costly information, such as from classified snow pits. To address this gap, we evaluate how well machine learning models can automatically segment and classify SMP profiles. We trained fourteen different models, among them semi-supervised models and artificial neural networks (ANNs), on the MOSAiC SMP dataset, a large collection of snow profiles on Arctic sea ice. We found that SMP profiles can be successfully segmented and classified into snow classes, based solely on the SMP's signal. The model comparison provided in this study enables practitioners to choose a model that is suitable for their task and dataset. The findings presented will facilitate and accelerate snow type identification through SMP profiles. Overall, snowdragon creates a link between traditional snow classification and high-resolution force-depth profiles. With such a tool, traditional snow profile observations can be compared to SMP profiles. [ABSTRACT FROM AUTHOR]

Soils are one of the main terrestrial carbon sinks and contain more carbon than the combined total in the atmosphere and terrestrial vegetation. A major challenge is quantifying how much carbon is stored in the soil and how much it has been sequestered due to changed management practices. In this study, a visible and near-infrared (VisNIR) penetrometer system was developed to measure in-situ soil VisNIR reflectance spectra to a depth of 90 cm into the soil profile. A spectral library of VisNIR soil spectra collected in air-dry and ground states were used to calibrate Cubist regression models for estimating soil organic carbon (SOC) contents. The External Parameter Orthogonalisation (EPO) transformation was applied to the in-situ spectra to remove soil moisture and other in-situ effects from the spectra. This penetrometer system was used to estimate SOC contents at three sites on three different days under variable soil moisture states. The penetrometer EPO performed better compared to the EPO constructed from moist cores. After applying EPO transformation matrix, soil wetness did not have any influence on soil SOC content estimations. The SOC contents were estimated using the in-situ VisNIR system were validated against lab-measured SOC content with mean R2, RMSE, and bias of 0.88, 0.32%, and 0.15%, respectively. It is concluded that the VisNIR penetrometer can potentially be used to measure SOC content rapidly and cost-effectively in-situ with a fine depth resolution. • A penetrometer system was used to acquire in-situ soil VisNIR spectra. • A spectral library from agricultural regions of NSW was used for calibration. • External Parameter Orthogonalisation (EPO) reduced confounding soil moisture effect. • External validation was performed to measure soil organic carbon contents. [ABSTRACT FROM AUTHOR]

Disturbance encountered when testing soft soils both in laboratory and in-situ conditions makes the determination of the undrained shear strength, Su, very challenging. This paper introduces a new tool called "Cylindrical Penetrometer" (CP) to measure the undrained shear strength of soft soils. Description of this tool is given, and the related shear test procedure is detailed. The proposed tool offers the advantage to avoid the disturbance of soft soils before the commencement of the CP test. From recorded measurements and based on considerations of the existing shear tests, a specific method of determination of Su is proposed. The experimental program included laboratory tests by using two sizes of the CP. The recorded results from CP tests, performed on a reconstituted Tunis soft clay, were compared with those obtained from direct shear tests, vane tests, and a consolidated undrained triaxial test. A fair agreement was found between the Cylindrical Penetrometer results with those obtained from the current shear tests. [ABSTRACT FROM AUTHOR]

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This paper presents (i) results from a series of instrumented free-fall penetration (FFP) tests performed, under laboratory-controlled conditions, in a large-scale testing facility and (ii) a simple methodology to predict undrained shear strength s u from FFP test data without resorting to assumptions on the values of different parameters. Comparison of soil resistance derived from acceleration data recorded during FFP tests with soil resistance recorded during constant rate penetration (CRP) tests using a ball penetrometer reveals unique relationships between dynamic and constant-rate penetration resistances for different shapes of FFP tools. Based on regression analysis, expressions are proposed for calculation of resistance ratio ξ r for three different shapes of FFP tool. The proposed expressions for ξ r further facilitate the prediction of undrained shear strength s u employing acceleration data recorded during FFP tests. FFP-based predictions of s u show excellent agreement with CRP-based s u prediction in three different laboratory testbeds. Furthermore, the proposed methodology successfully predicts s u profile at a field test site using FFP test data reported in the literature. • Results from a series of instrumented laboratory FFP tests in large-scale claybeds. • A simple s u prediction methodology based on FFP test data. • Shape of FFP tool affects penetration depth. • FFP and constant-rate ball penetrometer resistances follow a unique ratio. • Resistance ratio depends on normalized penetration depth of free-fall penetration. [ABSTRACT FROM AUTHOR]

The ASTM D6951 suggests a test method using the dynamic cone penetrometer (DCP) for the assessment of shallow pavement strength. This study is dedicated to evaluating a similar test method to be used for fine-grained clay–sand mixtures, which are commonly used to construct liners and fluid barriers. The liner layers include clay, which is water-sensitive. The shear strength of the liners depends mainly on the composition and proportions of the mixtures adopted. A series of tests were conducted in the laboratory for compacted clay–sand mixtures, including 5% and 10% bentonite material. The responses to advancing a dynamic probe into compacted material at three various moisture conditions—namely, the optimum, dry of optimum, and wet of optimum water contents—are investigated. The penetration profiles are compared for the two clay content levels selected and for three moisture state conditions. The clay–sand liners support vehicles and vibratory compactors during construction and when waste material is placed. The shear strengths of the mixtures are evaluated in the laboratory using direct shear tests. From the results obtained in this investigation, general guidelines and recommendations are presented to help with the efficient assessment of liners consisting of clay–sand mixtures. A cheap and quick approach to assess the density and shear strength of landfill liners or clay–sand layers can be achieved using a hand-held dynamic cone penetrometer. The state of moisture during compaction was found to influence the DCP results. The compaction of layers in a wet of optimum state is not expected to be an ideal alternative. [ABSTRACT FROM AUTHOR]

This paper presents the effect of confined granular fill on the efficiency of embedded PZT (Lead Zirconate Titanate) patches. The experiments are carried out to capture the dynamic response of confined granular fill and voltage output. The dynamic response of the system is analysed using the fast Fourier transformation (FFT) of vibration and digital static cone penetrometer (DSCP) test at various excitation frequencies. The peak pick method is used to determine the damping loss factor and natural frequency. The efficiency of voltage generation of embedded PZT patches is influenced by the depth of embedment, excitation frequency, location, and engineering properties of the confined granular fill. The results show that the influence of vibration frequency and placement of PZT on the output voltage should be considered. The thickness and engineering properties of granular soil affect the efficiency of voltage output. This study emphasizes the utility of PZT patches in the subgrade and structural health monitoring of various geotechnical structures. [ABSTRACT FROM AUTHOR]