Basic Geotechnical Properties Research Articles

Stabilization of Dredged Soil by Compensating the Sand Content in the Jhelum River

River dredging is crucial for mitigating the risk of floods by enhancing the water-carrying capacity of rivers. Nevertheless, the key difficulty lies in the appropriate disposal of dredged material, resulting in escalated costs. Predominantly consisting of silt, the dredged material demonstrates constrained bearing capacity and strength. Nonetheless, there is a prospect to derive value from excavated sediments, with potential applications in diverse public works projects. The processed product derived from dredged material can serve diverse purposes, such as filling railway and highway embankments, as well as the subgrade of pavements. The comprehensive study involved analyzing the fundamental properties of the dredged material collected from the Allochibagh flood channel of the Jhelum River. The analysis focused on determining the basic geotechnical properties of the soil mass. The tests unveiled the fine and cohesive nature of the dredged soil. To enhance its properties, sand was introduced as a stabilizing agent in varying proportions. The investigation revealed an initial augmentation in compressive strength as the proportion of sand increased, attaining an optimal mixture whereafter the strength declined. This study explores the utilization of sand as a stabilizing agent for dredged soil to enhance its strength and optimize its application. The process of stabilizing dredged soil with sand demands a thorough examination of hydrogeological processes, the specific characteristics of the dredged soil, and the intricate transport of contaminants. This formal and multidisciplinary effort seeks to elevate the overall stability of the soil.

AI-Based Estimation of Swelling Stress for Soils in South Africa

Soil swelling is one of the major causes of structural failure, due to excessive moisture saturation and desaturation moisture. In situ measurement of swelling stress is somewhat impossible and requires tedious routine site observation. The use of artificial intelligence to predict the swelling stress of in situ soil is highly recommended, because of the complex behavior of soil upon moisture absorption. Because of this challenge, this study is channeled towards the prediction of swelling stress using basic geotechnical properties to save the challenges of repeating geotechnical experimental tests. In this study, the swelling stress of soils collected from 15 locations in 5 sites across South Africa has been predicted by using the artificial neural network (ANN), genetic programming (GP), and evolutionary polynomial regression (EPR)-based intelligent techniques. Multiple data were collected through laboratory experiments on the predictors: gravimetric moisture content (GMC), plasticity index (Ip), dry density (γd), free swell index (FSI), degree of saturation (S), matric suction (Ψm) and the target, and swelling stress (Psm). This predictive model was aimed at proposing models, which will help earthwork designers and constructors in South Africa overcome the rampant visit to the laboratory in search of soil data needed for geotechnical engineering designs. The soils showed their potential for swelling, which was eventually confirmed by the sensitivity analysis of the intelligent models. The performance indices of the models showed that ANN outclassed the other techniques with a performance accuracy of 93.6% at an error of 1.9%. Also, the sensitivity analysis showed that the plasticity index and matric suction were the most influential to the models. With the predicted models, future earthworks in South Africa can quickly forecast swelling stress prior to designs and construction more so in hydraulically bound environments.

Utilization of Kenaf Core Fiber – Marine Clay Mixture as a Landfill Liner Material

Nowadays, leachate production is a big concern and causes a serious hazard to the soil and groundwater which causes the subsurface soil to be polluted as a result of the loss of soil quality and environmental pollution. This study aims to study the potential of using kenaf core fiber and marine clay mixtures as improved landfill liner material. Relevant laboratory tests such as atterberg limit test, specific gravity test, and particle size distribution were performed to examine basic geotechnical properties of marine clay soil collected from Batu Kawan, Penang. Besides that, compaction test and hydraulic conductivity test were carried out for soil mixed with kenaf core fiber to determine the strength and permeability characteristics. The results found that the marine clay has significantly adequate physical properties to be used as a landfill liner. The permeability test for marine clay soil inclusion of kenaf core fibre indicated that the hydraulic conductivity of the samples admixture for 0%, 4%, 8%, and 12% ranged between 6.68 × 10-9 and 1.57 × 10-8 m/s. Compaction of marine clay mix kenaf core fibre samples resulted in maximum dry density, ρdmax that ranged between 0.936 and 1.595 g/cm3 and optimum moisture content, wopt that ranged between 19.8% and 24%. Hence the inclusion of kenaf core fiber in marine clay soil improves the maximum dry density value, decrease permeability of marine clay and could be potentially used for landfill liner material.

Shallow Landslide Site Characterization using Electrical Resistivity Technique (ERT) at Balukhali Rohingya Refugee Camps of Ukhiya, Cox's Bazar, Bangladesh

As the geotechnical investigation is a challenging task due to natural heterogeneity and the limited data so the cheap surface geoelectric resistivity method is widely applied to know the complex subsurface information. To produce the electrical images for a site located at Balukhali Rohingya Refugee Camps area in Ukhiya-Teknaf, Cox’s Bazar, Bangladesh, a field data acquisition technique along with RES2DINV software has been performed. Two Wenner soundings on the 25 m and 50 m image lines at every 1 m and 2 m electrode spacing respectively reveal the shallow subsurface lithological variations. On the other hand, 34 samples were collected from two boreholes at different depths and tested under field and laboratory conditions to measure some basic geotechnical properties such as moisture content, grain size distribution, liquid limit, plastic limit, plasticity index, and specific gravity. These geotechnical parameters were compared with the constructed electrical images and confirmed the significance of the electrical resistivity values. Therefore, the geoelectrical resistivity method can be applied as an additional tool to support and enhance conventional geotechnical interpretation purposes as well as shallow landslide site characterization in Bangladesh.

Experimental Investigation on Black Cotton Soil Treated with Terrabind Chemical and Glass Powder

Abstract: Objectives: To improve the soil stability of Black Cotton (BC) soil which is abundantly found in East Godavari district and some costal areas of Andhra Pradesh in India as they are susceptible to detrimental volumetric changes, with changes in moisture. Methods: laboratory studies has been carried-out to investigate the influence of chemical called Terrabind on Balck Cotton (BC) soil from Amalapuram, East Godavari, Andhra Pradesh, and further the influence on BC when Terrabind is added in combination with Glass Powder (GP). Basic geotechnical properties like grain size distribution, specific gravity, consistency limits have been determined and engineering properties like Maximum Dry Density (MDD), Optimum Moisture Content (OMC), Unconfined compressive strength, California Bearing Ratio (CBR), and Triaxial compression test have been determined for untreated and treated soil. Swelling properties have been determined by conducting free swell index test and swell pressure test. The laboratory investigations were conducted for different curing days to determine the basic and engineering properties of soil such as Atterberg’s limits, grain-size distribution, MDD, OMC, CBR, Unconfined Compressive Strength (UCS), Strength, Durability, Fatigue and Resilient Modulus (E). Findings: There is no huge soil expansion in the consistency limits for the compound (which compound) treated BC soil. Untreated soil shows LL=63%, PL =32%, and PI =34%. For soil settled with Terrabind, PI has diminished from 28% for one day restoring to 24% for 28 days relieving period. For soil balanced out with Terrabind+GP, PI has diminished from 27 % for one day restoring to 18% for 28 days relieving period. Improvement in dry density of treated soil is peripheral. MDD expanded from 17.6 KN/m3 to 18.4 KN/m3 and 18.7 KN/m3, and OMC was decreased from 16.32% to 16.24% and 16.12% for soil settled with Terrabind and Terrabind + GP for 28 days restoring period individually. Swell strain test results showed that Swell tension diminished from 49.5 KN/m2 to 36.73 KN/m2 and 35.12 KN/m2 for soil settled with Terrabind and Terrabind+ GP tried following 7 days of restoring. Swell tension was decreased by 26% and 29% for soil settled with Terrabind and Terrabind+ GP individually. Novelty: Soil stabilized with Terrabind and GP has showed better results compared to soil stabilized with Terrabind. Percentage weight loss was less than 14% for 12th cycle of freeze- thaw, which shows that the stabilized soil has become durable. Swelling has reduced to a great extent. The swelling of soil stabilized with Terrabind and Glass Powder (GP) has reduced by 100%

Improving Very High Plastic Clays with the Combined Effect of Sand, Lime, and Polypropylene Fibers

Improving the mechanical properties of low-strength soils (e.g., high plasticity clays) is one of the main branches of geotechnical engineering. The adoption of stabilization techniques for ensuring that structures will be founded on an adequately strong soil base is a common practice. Stabilization techniques for clay soils may include inert materials (cohesionless soils), chemical substances (cement, lime, or industrial additives), or the use of randomly distributed fibers. While all of these additives are added to low-strength soils by mixing, the question remains whether an optimal combination of stabilization techniques can be achieved for maximizing soil strength. Besides, each one of these additives contributes to an increase in soil strength in a different manner (soil replacement, chemical bonding of soil particles, and soil reinforcement respectively), while, according to the literature, each technique has its limitations. The latter refers to a limited effect on strength improvement and a maximum possible percentage, beyond which an additive has an adverse effect on strength; it also refers to other factors, such as brittleness failure, material availability, overall cost, and environment-related issues. Hence, in the present study, the efficiency of improving the basic geotechnical properties of a very high plasticity clay (liquid limit ωl = 86%) with a coupled effect between dune sand, lime, and polypropylene (PP) fibers has been investigated. The samples prepared by combining the three aforementioned soil improvement techniques were compared in terms of plasticity, compaction characteristics, unconfined compressive strength (UCS), and California Bearing Ratio (CBR) index. The experimental results show that the combination of these additives may lead to a considerable improvement in the strength and ductility of soils, even with a small amount of lime additive. Also, it was observed that 20% of sand, 3.4% of lime and 0.9% of fibers (by wt%) offers the best performance in terms of strength improvement for the clay tested (i.e., 12.75 times improvement compared to the untreated clay).

Laboratory Evaluation of Undrained Shear Strength of a Soft Fine Grained Soils

The determination of undrained shear strength of soils is commonly achieved using triaxial testing in which specimen is carefully prepared before testing to maintain its original field condition. However, for soft soils preparing and handling specimens without causing any disturbance is a difficult job and may not always be successful. Other laboratory testing techniques can be adopted provided they can produce reliable results for such cases and can overcome the problem of pretest preparation process and hence avoiding any alteration of sample field condition. Extensive laboratory investigation on a soft marine soil recovered from sea bed offshore of Benghazi city, the testing program involves investigation of the basic geotechnical properties, focusing specifically on the determination of the undrained shear strength of such soils as determined by both the conventional unconsolidated undrained triaxial testing (UU) and the simple laboratory vane shear testing device (Miniature shear vane MV). The resulting shear strength obtained by UU-triaxial test, and resulting shear strength measured by Miniature shear vane MV were examined, compared and discussed on the light of other research works. Furthermore, the problems faced during testing soft samples in triaxial apparatus was also presented. The resulting undrained shear strength obtained by UU-triaxial test was found generally lower than that produced by Miniature shear vane MV which is attributed to sample disturbance before testing in triaxial. The study also demonstrates that despite of high scatter, the undrained shear strength obtained by MV can be reasonably comparable with the results of other investigations on soft soils.

Geo-electrical characterization of physical and mechanical properties of zinc tailing

In the present study, an attempt is made to characterize the tailing material using the electrical resistivity method through a series of laboratory experiments. Tailing materials are a by-product of the metal extraction industry, which are usually disposed off in the form of slurry to the disposal area surrounded by tailing impoundment. Nowadays, a large amount of water is removed through the filtration process, and dry stacking of tailing is followed. Effect of various basic (physical) geotechnical properties on the electrical resistivity of compacted tailing material is investigated using fabricated soil resistivity box based on four-electrode method (ASTM G57–20). To establish the correlation between electrical resistivity and permeability, measurements were made using modified rigid wall falling head permeameter at different densities. Triaxial shear tests, i.e., consolidated undrained (CU) test and consolidated drained (CD) tests were conducted on zinc tailings specimens to study the evolution of electrical resistivity with stress-strain and effective shear strength parameters (c’ and ϕ’) using customized triaxial cell. The present study can be useful for the estimation of in-situ soil properties using electrical resistivity measurement, which will help to understand the engineering properties of the compacted tailings and thus prevent failure of tailing dams.

Recycled Glass Blends with Recycled Concrete Aggregates in Sustainable Railway Geotechnics

This research investigates the static and cyclic characteristics of recycled glass (RG) as a supplementary material with recycled concrete aggregate (RCA) in the rail track capping layer. RG was blended by-weight with RCA in 10% increments up to 50% RG content. A performance-based laboratory testing scheme was designed according to the field loading conditions of capping layers in rail tracks. Basic geotechnical properties of RG + RCA blends were evaluated through their particle size distribution, compaction properties, and California bearing ratio. Effect of flooding was assessed with one-dimensional static and cyclic compression tests. Multistage triaxial compression tests were performed to determine the effect of RG content on shear strength parameters. A new repeated loading triaxial testing protocol was introduced for railway capping layer materials to assess the stiffness of RG blends to cyclic loading. Long term performance of samples also was evaluated through multistage cyclic permanent deformation tests. The shakedown concept was used to assess the permanent deformation results of RG + RCA samples. Results indicated that RG can be used effectively as a supplementary geomaterial in construction of rail track substructure.

Closure to “Discussion of ‘The Flow Index of Clays and Its Relationship with Some Basic Geotechnical Properties’ by G. Spagnoli, M. Feinendegen, L. Di Matteo, and D. A. Rubinos”

Abstract Considering the recent article on Flow Index and the basic correlation with some geotechnical parameters such as liquid limit, plastic limit, plasticity index, Cation Exchange Capacity, Specific Surface Area, Activity, and water uptake by Spagnoli et al. (2019), the authors reply to the discussers regarding their interesting comments.

Geophysical Methods and their Applications in Dam Safety Monitoring

The use of geophysical methods in dam sites investigations and safety monitory has proved their good value and versatility in many earthfill dam sites as early as the 1920s. In the following years great development has occurred in the methods, application procedures and tools used. They may be considered today as good ways for carrying out observation tasks on existing dams in non-intrusive and much faster and cheaper ways than the traditional geotechnical methods. It is possible using them to discover anomalies in the dam body or its foundation at an early stage and allowing quick intervention repair works. These methods seek to register and present variations in the basic geotechnical material properties in dams such as; bulk density, moisture content, elasticity, mechanical properties of rocks, electrical resistivity and mineralogy and magnetic properties and so forth. Such variations can indicate increasing seepage flow, progression in cracks’ sizes, formation of voids, caverns and other instability manifestations. Depending on how any investigation is carried out and the targeted anomaly, there is now selection of these methods such as: Electromagnetic Profiling (EM), Electrical Resistivity Tomography (ERT), SelfPotential (SP), Ground Penetration Radar (GPR), variety of Seismic Methods (SM) which can be applied using such equipment as in Seismic refraction, Seismic Reflection, Multi Analysis of Rayleigh surface waves (MASW) instruments, or using Refraction Micrometer (ReMi), macro-gravity method, and Cross-Hole Seismic Tomography. In addition, Temperature Measurements and other less used methods can be used like Microgravity measurement, Magnetic Profiling and Radio Magnetotelluric methods. An attempt is made here to cover the details of these methods, their advantages and limitations and to prove their usefulness in many dam sites all over the world. One observed issue is their adaptability to embankment dams more than to concrete dams and their popularity for checking seepage related problems and material changes within dam bodies and their foundations such as formation of voids and sinkholes.

Discussion of “The Flow Index of Clays and Its Relationship with Some Basic Geotechnical Properties” by G. Spagnoli, M. Feinendegen, L. Di Matteo, and D. A. Rubinos, published in Geotechnical Testing Journal 42, no. 6 (2019): 1685–1700

Discussion of “The Flow Index of Clays and Its Relationship with Some Basic Geotechnical Properties” by G. Spagnoli, M. Feinendegen, L. Di Matteo, and D. A. Rubinos, published in Geotechnical Testing Journal 42, no. 6 (2019): 1685–1700

Strength and Workability Improvement Potential of Admixture of Corn Cob Ash and Cement for Stabilizing Lateritic Soil

A natural lateritic soil classified as A-7-5 (10) and CL based on AASHTO and USCS classification systems, was stabilized with up to 5% cement admixed with up to 12% CCA to assess their effect on its basic geotechnical properties such as particle size distribution, Atterberg limits, compaction, unconfined compressive strength and California bearing ratio. The liquid limit decreased and plastic limit increased while there is a reduction in corresponding plasticity index of the clay soil. There was an increase in Maximum Dry Density (MDD) and Optimum Moisture Content (OMC) of the stabilized soil sample, which increased with the increasing content of CCA and cement. Both the Unconfined Compressive Strength (UCS) and California Bearing Ratio (CBR) of the soil increased with increasing percentage of cement and CCA. Based on the results of this study, corn cob ash (CCA) cannot be used as a stand-alone stabilizer for this lateritic soil but with a more potent stabilizer for clay soil such as lime. It is therefore recommended that the mixture of 12% CCA and 2.5% cement could be used to stabilize A-7-5 (10) lateritic soil for use as subbase material and 12% CCA and 5.0% cement could be used to stabilize A-7-5 (10) lateritic soil for use as base material for improving pavement structure in terms of strength, stability and workability. Keywords: Lateritic soil, Corn cob ash, Cement, Stabilization, Strength and Workability DOI : 10.7176/JIEA/9-7-06 Publication date: December 31 st 2019

Peat Stabilization by Using Sugarcane Bagasse Ash (SCBA) as a Partial Cement Replacement Materials

Malaysia are covered approximately 2.6 million hectare of peat and facing serious geotechnical problems to develop infrastructure on peatland area. This study is to observe the basic geotechnical properties, strength and compressibility behavior of Pontian peat that stabilized by cement (OPC) and sugarcane bagasse ash (SCBA). The whole laboratory test standards and regulation that had been used in this study was adopted from American Society for Testing and Materials (ASTM) and British standards (BS). In order to understand an improvement of peat stabilization, unconfined compressive strength (UCS) and 1D-Oedometer consolidation test were conducted on untreated and stabilized peat. The results show that Pontian peat can be considered as hemic peat with average acidic. It was observed that the treated peat with 5% of SCBA (PCB5) has the highest UCS of 190 kPa and was discovered to be equivalent to PC specimen. There was a noteworthy decrease of void ratio, e for optimum PCB and PC mixtures as compared to untreated peat. The value of Cc and Cα was quite low at small effective stresses, however it improved after beyond preconsolidation pressure, σ’c. Compared to untreated Pontian peat which contributed the ratio of Cα/Cc about 0.056, stabilized peat for PC and PCB5 gave better ratio with 0.0316 and 0.0273 respectively. Results shows that the treated peat Cα/Cc ratios were drop dramatically from untreated peat which is representing the stabilized mixture can efficiently reduce the secondary compression.

Effect of palm oil on the basic geotechnical properties of kaolin

This paper presents an experimental study to evaluate the effect of palm oil on the selected basic physical-chemical and geotechnical properties of kaolin. The experimental findings are further compared with literature outcomes investigating similar properties of fine grained soils subjected to contamination by different types of oils. To this end, palm oil was mixed with oven dried kaolin samples–aiding oil\'s interaction (coating) with dry particles first, in anticipation to emphasize the effect of oil on the properties of kaolin, which would be difficult to achieve otherwise. Oil content was limited to 40% by dry weight of kaolin, supplemented at intervals of 10% from clean kaolin samples. Observations highlight physical particle-to-particle bonding resulting in the formation of pseudo-silt sized clusters due to palm oil\'s interaction as evinced in the particle size distribution and SEM micrographs. These clusters, aided by water repellency property of the oil coating the kaolin particles, was analyzed to show notable variations in kaolin\'s consistency–measured as liquid and plastic limits. Furthermore, results from compaction tests indicates contribution of oil\'s viscosity on the compaction behavior of kaolin – showing decrease in the maximum dry unit weight (gammad,max) and optimum moisture content (wopt) values with increasing oil contents, while their decrease rates were directly and inversely proportional in gammad,max and wopt values with oil contents respectively. Comparative study in similar terms, also validates this lower and higher decrease rates in gammad,max and wopt values of the fine grained soils respectively, when subjected to contamination by oil with higher viscosity.

The Flow Index of Clays and Its Relationship with Some Basic Geotechnical Properties

The flow index (FI), which is the slope of the water content versus log10 of the blows number plot for the Casagrande cup method, is the measure of the rate at which soil mass loses its shear strength with increased water content. FI was plotted against the plasticity index (PI) of 59 clays; each clay had a different mineralogy and origin, and together they accounted for a wide range of plasticity values. A linear relationship with R2 = 0.91 was observed. However, if FI is plotted against the liquid limit (LL) and the plastic limit (PL) separately, although a good correlation with LL is observed, FI poorly correlates with PL. FI was also correlated with the activity of soil, cation exchange capacity, specific surface area, and water uptake. Predicted equations from PI and activity were established on 13 independent samples confirming that a good correlation against measured values and estimated values (from FI) exists. From the literature review, FI was also used to indirectly estimate PL. Results show a trend, albeit the results are scattered (R2 = 0.66 for the Casagrande cup method and R2 = 0.76 for the cone penetrometer method), thus indicating that PL cannot be directly obtained from FI.

Correlations between electrical resistivity and basic engineering property parameters for marine clays in Jiangsu, China

This paper presents an investigation to evaluate the influence of basic geotechnical properties on the electrical resistivity (ρ) of marine clay. The resistivity piezocone cone penetration tests (RCPTU) were conducted to measure the resistivity at 6 sites in Jiangsu, China. The correlationship between resistivity and soil parameters, including salt content of pore fluid (cs), clay content (wc), sensitivity (St), plasticity index (Ip), unit weight (γ), and moisture content (w), was investigated to understand the mechanisms controlled the changes in resistivity.The results reveal that ρ value was strongly controlled by both cs and wc, in which the ρ decreased rapidly with an increase in cs and wc by forms of power and exponential functions, respectively. Resistivity decreased with an increase in Ip for the low plasticity clays (Ip < 10%), while it presented almost a constant value (8 Ω·m) for medium and high plasticity soils (Ip > 10%). For the range of resistivity studied, poor statistical relationships between ρ and St, γ, and w were observed, which was mainly due to the dilution effect of controlling factors (viz., cs and wc). These observations could provide assistance to engineering designers in the interpretation of resistivity surveys in marine clay areas.

Determination of Soil Moisture Content using Laboratory Experimental and Field Electrical Resistivity Values

The efficiency of civil engineering structure require comprehensive geotechnical data obtained from site investigation. In the past, conventional site investigation was heavily related to drilling techniques thus suffer from several limitations such as time consuming, expensive and limited data collection. Consequently, this study presents determination of soil moisture content using laboratory experimental and field electrical resistivity values (ERV). Field and laboratory electrical resistivity (ER) test were performed using ABEM SAS4000 and Nilsson400 soil resistance meter. Soil sample used for resistivity test was tested for characterization test specifically on particle size distribution and moisture content test according to BS1377 (1990). Field ER data was processed using RES2DINV software while laboratory ER data was analyzed using SPSS and Excel software. Correlation of ERV and moisture content shows some medium relationship due to its r = 0.506. Moreover, coefficient of determination, R2 analyzed has demonstrate that the statistical correlation obtain was very good due to its R2 value of 0.9382. In order to determine soil moisture content based on statistical correlation (w = 110.68ρ-0.347), correction factor, C was established through laboratory and field ERV given as 19.27. Finally, this study has shown that soil basic geotechnical properties with particular reference to water content was applicably determined using integration of laboratory and field ERV data analysis thus able to compliment conventional approach due to its economic, fast and wider data coverage.

The Influences of Basic Physical Properties of Clayey Silt and Silty Sand on Its Laboratory Electrical Resistivity Value in Loose and Dense Conditions

Non-destructive test which refers to electrical resistivity method is recently popular in engineering, environmental, archaeological and mining studies. Based on the previous studies, the results on electrical resistivity interpretation were often debated due to lack of clarification and evidences in quantitative perspective. Traditionally, most of the previous result interpretations were depending on qualitative point of view which is risky to produce unreliable outcomes. In order to minimise those problems, this study has performed a laboratory experiment on soil box electrical resistivity test which was supported by an additional basic physical properties of soil test like particle size distribution test (d), moisture content test (w), density test (ρbulk) and Atterberg limit test (LL, PL and PI). The test was performed to establish a series of electrical resistivity value (ERV) with different quantity of water content for clayey silt and silty sand in loose and dense condition. Apparently, the soil resistivity value was different under loose (L) and dense (C) conditions with moisture content and density variations (silty SAND = ERVLoose: 600 - 7300 Ωm & ERVDense: 490 - 7900 Ωm while Clayey SILT = ERVLoose: 13 - 7700 Ωm & ERVDense: 14 - 8400 Ωm) due to several factors. Moreover, correlation of moisture content (w) and density (ρbulk) due to the ERV was established as follows; Silty SAND: w(L) = 638.8ρ-0.418, w(D) = 1397.1ρ-0.574, ρBulk(L) = 2.6188e-6E-05ρ, ρBulk(D) = 4.099ρ-0.07 while Clayey SILT: w(L) = 109.98ρ-0.268, w(D) = 121.88ρ-0.363, ρBulk(L) = -0.111ln(ρ) + 1.7605, ρBulk(D) = 2.5991ρ-0.037 with determination coefficients, R2 that varied from 0.5643 – 0.8927. This study was successfully demonstrated that the consistency of ERV was greatly influenced by the variation of soil basic physical properties (d, w, ρBulk, LL, PL and PI). Finally, the reliability of the ERV result interpretation can be enhanced due to its ability to produce a meaningful outcome based on supported data from basic geotechnical properties.

A Field Soil Moisture Study Using Time Domain Reflectometry (TDR) and Time Domain Transmissivity (TDT) Sensors

This paper presents the results of a field study conducted at three different locations close to the campus of University of Texas at Arlington, Texas. Time Domain Reflectometry (TDR) and Time Domain Transmissivity (TDT) Sensors were installed at depths of 5 cm, 10 cm, 25 cm, 50 cm, and 100 cm below ground level. The soils at the three sites were tested for basic geotechnical properties such as size analysis, specific gravity, density, and hydraulic conductivity. In-situ infiltration tests were also performed to determine filed hydraulic conductivity. The observed moisture data response very well with recorded rainfall event and infiltration were greatly affected by rain intensity and duration.