Vane Shear Research Articles

Use of seawater as an accelerator in 3D printed concrete (3DPC)

Seawater (SW) is one of the viable alternatives to replace freshwater (FW) for producing concrete in regions facing extremely severe water stress. Seawater has high potential to be used as a set-on-demand accelerator among the other expensive materials being widely researched in additive manufacturing. The current study evaluated the progress of heat of hydration in 3DPC-FW and 3DPC-SW mixes using isothermal calorimetry. Furthermore, fresh and early-age properties of these mixes were studied using a flow table, manual shear vane, uniaxial unconfined compressive strength tests, and dynamic elastic modulus development. Strength development and shrinkage progress up to 28 days were evaluated. A detailed investigation reveals that an increase in compressive strength from the very first hours of hydration, a reduction in workability which could be compensated by modifying SP, and higher shrinkage were observed in SW-mixed 3DPC compared to the FW-mixed counterpart. Furthermore, the potential improvement in the speed of printing is highlighted in this study with 3DPC-SW mix demonstrating acceleration in early strength.

Effect of granite powder on the strength, durability and sustainability of soil treated using steel slag or cement

Granite powder, a byproduct of granite quarrying, enhances the long-term strength of cement-treated soil due to its pozzolanic reactivity. However, its effects on early strength and seawater durability, as well as its influence on slag-treated soils, remain unexplored. We studied cement-treated and slag-treated soil composites with 0 % and 30 % granite powder, using 8 % cement or 30 % steel slag per dry soil mass. We performed vane shear and unconfined compressive strength (UCS) tests at 1, 3, 6, 12 hours, and 1, 3, 7, 28, 63, 91, 119 days. After 28 days of air curing, samples endured seawater exposure at 30°C for 0, 28, 63, and 91 days, followed by UCS and XRF calcium composition tests. Seawater samples were also analyzed for calcium and magnesium concentrations using a photometer. Despite similar dry unit weights, slag-treated soil initially exhibited lower strength than cement-treated soil. However, granite powder enabled slag-treated samples to reach comparable strength levels to those of cement-treated soil. Its pozzolanic reactivity facilitated self-repair in samples affected by seawater-induced calcium depletion, while also reducing emissions, resource consumption, and construction costs associated with treated soil materials.

Bio-Electrokinetic Improvement of Deltaic Soil

In addressing problematic soils, geotechnical engineers employ two key strategies: compatibility and improvement. This study focuses on soft and CL deltaic sediments, and seeks to enhance cementation by investigating microbially-induced calcium carbonate precipitation (MICP). Sporosarcina pasteurii bacteria, together with a cementation solution (urea and calcium-containing salt), were electrokinetically injected into deltaic clay soil from the Telar River in Iran. The initial samples, with a dry unit weight (γd) of 12.75 kN/m³, underwent injections in two modes: simultaneous injection of the bacterial and cementation solutions and individual injection in a sequential order. Unconfined compression strength tests and laboratory vane shear tests were conducted to assess changes in soil strength parameters, while a consolidation test was performed to investigate alterations in soil settlement parameters. A comparative analysis with an electroosmosis control sample revealed a remarkable increase in compressive strength and undrained shear strength for MICP bio-electrokinetic improvement. Moreover, the consolidation test demonstrated that the compression index (Cc) and recompression index (Cr) exhibited a more pronounced decline in the simultaneous injection than individual injection. This highlights the dual impact of the bio-electrokinetic method, namely the enhancement of shear strength and the mitigation of settlement in deltaic clay soil. The calcium carbonate content was measured for the samples, and the results indicated a higher degree of participation for the samples subjected to simultaneous injection. Microstructure analyses were conducted on samples, and calcite and vaterite were observed in bio-cemented samples.

Adopting a systems engineering approach to a feasibility study of a sidings development at the Midsomer Norton railway station

It is planned to reopen Midsomer Norton railway station, which is a station on the Somerset & Dorset Heritage Railway Line, to traffic. As a first step, Midsomer Norton will be a terminus, and it is proposed to build sidings and a depot for the trains that terminate there. However, a ground investigation is essential before commencing construction of the sidings and the depot, as this is a vital part of any civil engineering process. The behaviour of the ground must be known in order for a structure to be supported by it; therefore, data from the ground investigation are used as reference for any kind of structure development. This study covers a site investigation that includes a desk study, walkover survey, sampling and laboratory testing in order to ascertain the feasibility of a suitable design. Moisture content testing, liquid limit and plastic limit tests, standard compaction testing, shear vane tests, and triaxial compression tests were carried out to determine the soil characteristics and to analyse the soil behaviour. A strong recommendation was made to follow a systems engineering approach in the construction phase, as well as in the design stage. The dependability of the system is ensured by the good use of V – process of systems engineering.

Challenges in the measurement of cross-shore geotechnical characteristics of sandy beach surface sediments

Geotechnical properties of surficial beach sediments affect beach erosion and shoreline changes. This study sets out to measure relative density, moisture content, friction angle, and shear strength of sandy beach surface sediments from dune to swash zone towards the goal of assessing their importance in sandy beach morphodynamics. Methods of sediment sampling, a conductivity based moisture probe, field penetrometers, and a field vane shear were deployed to collect data at the sandy Atlantic-side beach in Duck, North Carolina. The tools used were assessed based on their operability in the beach environment and data quality, and results are discussed in the context of beach morphodynamics. A digital field vane shear provided an efficient and direct method of measuring shear strength, but the difficulty of computing stresses on the failure plane, which is necessary to validate the results, ultimately reduced the usability of this instrument. The results from three penetrometers were compared to a partially-saturated bearing capacity model, where a portable free-fall penetrometer yielded the best fit. However, a modified velocity-dependent strain rate correction factor (K=0.31vi) was required to convert dynamic sediment resistance to a quasi-static resistance for the partially saturated sands. A small-scale digital push in penetrometer also achieved a positive correlation when compared to moisture content, but the small tip diameter (5 mm) coupled with the grain size at the beach (0.35 mm) raised concerns about the ability to derive an accurate measure of strength. It was determined that estimating strength parameter using a partially saturated bearing capacity model was appropriate for water contents less than 25% by volume, or anywhere in the crosshore above the swash to the dune. Relative density and moisture content were found to be closely linked, with partial saturation resulting in samples that featured negative relative densities up to −40%.

Coupled DEM-FDM numerical model for EPB shield tunnelling simulation with foam conditioning

It is widely recognized that an appropriate application of soil conditioning significantly improves the tunnelling performance of earth pressure balance (EPB) shield tunnel boring machines (TBMs). This study presents a numerical approach that simulates an EPB shield tunnelling, considering the injection of foam into the soil. To enhance computational efficiency and reduce the number of particles simulated in the ground formation, the numerical study coupled the discrete element method (DEM) and the finite difference method (FDM). The properties of in-situ soil and foam-conditioned soil were incorporated into the DEM domain by determining the contact parameters of particles using two calibration models: the triaxial compression test and the pressurized vane shear test models. With the established model, tunnelling analyses were conducted under specific TBM operation conditions, such as the penetration rate, and rotational speed of the cutter head and the screw conveyor. The effect of foam injection on EPB shield TBM operation was evaluated by adjusting the contact parameters of DEM elements. The numerical simulations revealed that foam conditioning reduced the torque, thrust force, and forces on cutting tools. These simulations provided valuable insights into the applicability of the numerical approach in assessing foam conditioning for EPB shield TBMs.

Laboratory Study on Vallejo and Scovazzo’s Methods in Estimating the Rheology Parameters of Bentonite and Kaolinite Muds

The mud undrained shear strength and viscosity are the essential parameters in understanding the behavior of mudflow. One of the laboratory test methods to estimate the undrained shear strength and viscosity is Vallejo and Scovazzo’s cylinder strength meter test (CSMT) and flume channel test, respectively. This paper compares the undrained shear strength of kaolin and bentonite muds obtained from the CMST to those obtained using the fall cone and mini vane shear tests and also studies the scale effects in the flume channel test in measuring the mud viscosity at a 20o to 40o slope angles and at various liquidity indexes. The results exhibit that CMST could estimate the undrained strength of mud as low as 0.45 kN/m2 with a liquidity index of up to 5.93. Then, the reduction of the size of the flume channel by half resulted in a mud viscosity of about 2.3 times higher.

Evaluating undrained shear-strength of marine clay using free-fall penetration considering uncertainty: an experimental and Bayesian analysis study

ABSTRACT Free-fall penetration (FFP) testing has drawn wide attention in evaluating in-situ undrained shear-strength (S u) of marine clay because it can save time and reduce costs. However, model parameters for interpreting S u are empirical and usually determined based on engineering experience, leading to great uncertainties in S u 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 S u, 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 S u of the three penetrometers. Results show that updated S u samples were consistent with those determined by vane shear tests, which verified the reliability of proposed model parameters.

Geotechnical, microscopic and mineralogical characterization of surficial sediments nearshore the southern coast of Brazil

ABSTRACT Many important maritime projects depend on the correct characterization of surficial sediments (e.g. gas and water pipelines; dredging works; transport of sediments, and water-soil-structure interaction). However, the sampling and characterization of such sediments are very challenging due to the environmental conditions. Furthermore, the investigation often consists only of a basic granulometric analysis. In this context, this paper presents a geotechnical, mineralogical, and microscopy characterization of an offshore area on the southern coast of Brazil. Surficial samples were collected from the seabed, in water depths between 13.0 and 91.0 metres. Then, they were submitted to basic geotechnical characterization tests (size distribution by sieving and sedimentation, Atterberg limits, and basic physical properties), mineralogical analysis by X-ray diffraction tests (XRD), microscopy investigation by scanning electronic microscopy (SEM) and shear vane tests. Based on the state and index parameters of the sediments, as well as the undrained shear resistance, three main sets of sediments have been identified: group I (sands), group II (clayey sands), and group III (mixtures of sand, silt, and clay). The spatial distribution of sediments was also inferred, reflecting different deposition environments and bottom dynamics. The clay mineral quantification through XRD revealed that the predominance of 2:1 clay minerals is related to the higher plasticity found in some samples. Moreover, the presence of diatoms could explain the difference in porosity in the samples, resulting in a higher plasticity and lower shear strength.

Characterization of an organic soil deposit using multi-faceted geotechnical field and laboratory investigations

The findings from a comprehensive characterization of an organic soil deposit using multi-faceted geotechnical field and laboratory investigations are presented. The field-testing program comprised cone penetration testing (SCPT) with shear wave velocity (Vs) measurements, full-flow ball penetration testing (BPT), and electric vane shear testing (eVST). The work was supplemented by a laboratory program comprising index testing, one-dimensional consolidation testing, and direct shear testing conducted on the tube and disturbed soil samples obtained from the site. Data originating from this wide range of testing tools deployed at a single site provided a unique opportunity to get insights into the strength and stiffness properties of organic soils and examine possible correlations between such properties and test measurements. The work confirmed the suitability of BPT for characterizing organic soils due to its ability to mobilize/test a larger representative volume of soils during penetration, thereby reflecting a practical average response for the tested soil mass. It was possible to develop simple correlations to directly estimate the small-strain stiffness (Gmax) and undrained shear strength (Su) of organic soils using data from BPT. With these capabilities, combined with the simplicity and the relatively easy field deploy ability, BPT emerges as a tool with high applicability for the geotechnical characterization of organic soils - an activity essential to support the design of buried energy pipelines that traverse over large distances in remote muskeg terrains in Canada.

An Attempt to Predict the Effective Angle of Internal Friction for Remolded Clayey Soils Using the Vane Shear Test: Some Important Implications

An Attempt to Predict the Effective Angle of Internal Friction for Remolded Clayey Soils Using the Vane Shear Test: Some Important Implications

Undrained Shear Strength from Field Vane Shear Test (VST) of Soil at Shoreline Area

The effect of soil shear strength at the shoreline area is the focus of this study. Pantai Punggur, Batu Pahat, Johor, has been chosen as the subject location for the soil shear strength investigation. It is located on the west coast of Johor, with latitudes ranging from 1.62° to 1.87° N and longitudes ranging from 102.78° to 103.19° E. The purpose of this study is to use a field vane shear test (VST) to determine the undrained shear strength of shoreline areas. Soil samples were collected at specific locations known as Zones A, B, C, D, and E, and data for sediment shear strength was obtained from field vane shear test (VST) methods. From the undrained shear strength test at 0.5 m depth at high tide (HT) and medium tide (MT) data for December 2021, Zone A had a Cu reading of more than 4.5 kPa, followed by Zones B, C, and D, and lowest at Zone E. Next, in the December 2021 data at the HT level, Zone A has a Cu reading greater than 4.5 kPa at 0.5 m and 1.0 m, while other Zones have readings less than 3.0 kPa. It can be concluded that the depth of a part also influences the data in this study. When the depth increases, the shear strength of the data also increases. This study will serve as a benchmark for future conservation efforts. Based on the findings, more effective control measures for preserving and conserving coastal areas may be developed.

Dry granular flow in a vane shear cell: flow characteristics and rheological laws

The flow dynamics of dry granular flows is significantly affected by a prominent feature of a granular mass known as dilatancy. Although their rheological behaviour has been characterised via friction and dynamic dilatancy laws, the role of dilatancy in a granular flow has not been much appreciated. In this study, using a vane rheometer, an experimental investigation was conducted on uniform glass beads of (d = 3 mm) at different initial relative densities (15 ≤ Dr ≤ 66%) and shear rates that span over four orders of magnitude. The flow characteristics in terms of effective friction, volume change, and velocity field were obtained and evaluated. The effective friction shows a descending-ascending pattern corresponding to a transitional behaviour from a velocity-weakening solid-like to a velocity-strengthening liquid-like behaviour. The volume-change measurements show that all specimens dilate and reach almost the same density at each shear rate. The velocity field follows a Gaussian pattern characterized by the slipping velocity at the boundary, the interlayer slippage between particles, and the interlayer disorder of the particles. A new non-monotonic friction law and a dynamic dilatancy law are presented as governing rheological laws based on the inertial number and by introducing an effective dilation coefficient. This effective dilation coefficient successfully captures the role of dilation-induced secondary vortex flows in the dry granular flows.

Influence of Rate Effects, Temperature, and Moisture Content on the Geomechanical Behavior of Marine Clays

Abstract The study of the geomechanical behavior of marine clays is a basic requirement for project optimization of the oil and natural gas industry. As part of a large-scale project, this study explored the effects of moisture content, temperature, and rate effects using laboratory vane shear tests. A series of results has helped in the identification of the effects of ground freezing on the undrained shear strength. For temperatures below freezing (−2.0 °C) the undrained shear strength increases with increasing water content and decreases with increasing shear rates for applied angular velocities in the range of 0.0025– 0.015 rpm. Apparently, with the freezing of pore fluids, the shear strength is partially governed by the strength of the ice-soil particle bonds. The increase in shear rate appears to facilitate the breakage of the ice bonds and afterwards the ice crystals reducing the viscous effects on the mobilized shear strength. Conversely, samples tested at temperatures above freezing show an increase in undrained shear strength with the increase in the imposed angular velocity and decreases with increasing soil moisture. Based on these studies, it is concluded that rate effects should be coupled to the influence of temperature and moisture content in the design of offshore structures.

Affordable inline structuration measurements of printable mortar with a pocket shear vane

The control of mortar rheology is of paramount importance in 3D printing concrete by extrusion. This is particularly sensitive for two-component (2K) processes that use an accelerator to switch the printed mortar very quickly from a liquid behavior to a sufficiently solid behavior to be able to be printed (i.e. structuration). After some main key points about measuring the structuration of printed mortars, we propose an original and simple inline test using a pocket shear vane tester. The test is able to measure over several decades of yield stress range, mobilizes small quantities of mortar and enables in-situ measurements on freshly printed layers. The results highlight the difference of structuration between a benchtop-prepared printable material and a truly printed material, fostering the importance of inline measurements, and demonstrating the quality of the method. This pocket shear vane test appears as good contender for a light and affordable rheometer for 2K printable mortars.

A new portable field rotational viscometer for high-temperature melts.

Mounted on top of furnaces, laboratory viscometers can be used for the rheological characterization of high temperature melts, such as molten rocks (lava). However, there are no instruments capable of measuring the viscosity of large volumes of high temperature melts outside the laboratory at, for example, active lava flows on volcanoes or at industrial sites. In this article, we describe a new instrument designed to be easy to operate, highly mobile, and capable of measuring the viscosity of high temperature liquids and suspensions (<1350 °C). The device consists of a torque sensor mounted in line with a stainless-steel shear vane that is immersed in the melt and driven by a motor that rotates the shear vane. In addition, a thermocouple placed between the blades of the shear vane measures the temperature of the melt at the measurement location. An onboard microcomputer records torque, rotation rate, and temperature simultaneously and in real time, thus enabling the characterization of the rheological flow curve of the material as a function of temperature and strain rate. The instrument is calibrated using viscosity standards at low temperatures (20-60 °C) and over a wide range of stress (30-3870Pa), strain rate (0.1-27.9s-1), and viscosity (10-650Pas). High temperature tests were performed in large scale experiments within ∼25 l of lava at temperatures between 1000 and 1350 °C to validate the system's performance for future use in natural lava flows. This portable field viscometer was primarily designed to measure the viscosity of geological melts at their relevant temperatures and in their natural state on the flanks of volcanoes, but it could also be used for industrial purposes and beyond.

Evaluation of Stress History and Undrained Shear Strength of OC Clayey Soil in Northern Jakarta

It is difficult to determine the accurate undrained shear strength (su) of clay with complicated stress history. In addition to the laboratory tests such as Triaxial UU and Unconfined tests, the in-situ tests such as Vane Shear, SPT, and CPTu tests were conducted for undrained shear strength evaluation. Moreover, the overconsolidation ratio (OCR) by CPTu correlation presented the soil stress history profile along the depth and the Oedometer tests were used to evaluate the results. It was found that the clayey soil is overconsolidated up to -31.0 m below the surface in Northern Jakarta due to groundwater extraction. The Stress History and Normalized Soil Engineering Properties (SHANSEP) formula is widely used to model the relationship between undrained shear strength, OCR, and vertical shear stress. The su results from laboratory and in-situ tests showed good agreement with SHANSEP formula. Moreover, several empirical formulas for OC clayey soil were developed for future deep excavation projects in Jakarta area.

PENGENALAN DAN PELATIHAN PENGAMBILAN SAMPEL TANAH DISTURBED DAN UNDISTURBED UNTUK SISWA SMK 7 BIDANG KEAHLIAN KONSTRUKSI JALAN, IRIGASI, DAN JEMBATAN

&lt;p&gt;One of the challenges faced by students from SMK is the learning atmosphere and learning system applied by PTV. This is due to the gap between the SMK curriculum and PTV. State Vocational High School (SMKN) 7 Semarang is one of the vocational schools located in the city of Semarang. SMKN 7 Semarang has 8 expertise competencies, one of which is competence in the field of civil engineering, namely Building Construction, Sanitation and Maintenance (KGSP) and Road, Irrigation, and Bridge Construction (KJIJ). Students of SMKN 7 Semarang already have a basic understanding of civil engineering, but when they enter the PTV world, they still experience difficulties in several fields. Therefore, to bridge and fill the gap from the SMK curriculum to PTV, it is necessary to introduce and train related fields of civil engineering, one of which is field testing. Semarang State Polytechnic as one of the universities has competent human resources to provide solutions to these problems. The PKM team provided introduction and training on the use of hand drill and vane shear tools used for soil testing. The hand drill is used to take disturbed and undisturbed soil samples, while the shear vane is used to determine the shear condition of the soil. After conducting the introduction and training activities, students can better understand how to use the test equipment. In addition, students also understand better in analyzing soil data obtained from testing.&lt;/p&gt;

Changes in soil physical and mechanical properties under different tillage and cropping systems in alfisol soil of southwestern Nigeria

Sustainable agricultural strategies such as conservation agriculture (CA) and integrated land management are required to mitigate land degradation and food insecurity. This study was conducted to investigate the effects of different cropping systems: sole sorghum (SOR), sole cowpea (COW), sole soybean (SOY), sorghum-cowpea intercrop (SC), and sorghum-soybean intercrop (SS); and tillage practices: conventional tillage (CT), no tillage (NT), and compacted no till (NTc) on physical and mechanical properties of an Alfisol in Southwestern Nigeria. The experimental layout comprised a split plot design accommodating the 3 tillage and 5 cropping systems in a randomized complete block design with three replications. Undisturbed soil samples were collected from 0 to 15 ​cm, and 15–30 ​cm soil layers for the determination of soil bulk density (BD), total porosity (TP), and unconfined compressive strength (quf). The results showed that bulk density was lower, while total porosity was higher under intercrops than monocrops in all the tillage treatments. Conventional tillage had the least BD compared to no tillage and compacted no till plots. Soil vane shear strength (Ʈ) and unconfined compressive strength (quf) were generally lower under the intercrops than the sole sorghum plots. Averaged over the two soil depths, the mean soil quf of SS intercrop was 1.28 times lower than the mean soil quf of SOR but was 1.06 times higher than the mean soil quf of SOY. SC intercrop had a 14.20% and a 9.15% lower average soil quf than SOR and COW in 2019. Unconfined compressive strength and vanes shear strength significantly positively correlated with BD and negatively with TP, organic carbon (OC), organic matter (OM), and total nitrogen (N) in both cropping years. The research demonstrates that farming approaches that integrate soil cover preservation and minimal soil disturbance with diverse cropping systems improve soil physical and mechanical behavior.

Determination of Atterberg Limits using the vane shear test method

Atterberg limits are important index parameters used to classify soils for various engineering applications. Engineering properties of soils are predicted through simple correlations with index properties and thereby the engineering behavior of soils are qualitatively assessed. There are two popular methods of determining liquid limit, and plastic limit is commonly determined adopting rolling thread methods. To avoid operator related variations in determining plastic limit by conventional method, some researchers have explored using cone method as an alternative. However, there is no consensus about the depth of penetration to reckon the end of plastic state. Though various other test methods have been developed to determine plastic limit (like roll plate device), cone penetration with its limitation of determining plastic limit, is the only method to determine both liquid and plastic limit of soils. Since laboratory vane shear test is a simple and reliable method of determining undrained strength of fine-grained soils, the authors have explored to determine both liquid and plastic limits through correlations developed between undrained strength and water content over a range of consistencies between liquid and plastic states. This would eliminate determining liquid and plastic limit separately without sacrificing the reliability of results.