Engineering Properties Of Soil Research Articles

A mathematical model for determining engineering soil classifications from pedological data

Various pedological soil classification systems exist worldwide, including an internationally accepted system and various national systems, many of which have been incorporated into databases that include maps. Various physical and chemical soil properties are used for classifying soils according to these pedological systems. This paper proposes an approach which may be used to determine the engineering properties of soils from the physical and chemical properties that are used to pedologically classify soils by systems, and, in particular, the South African Binomial System. These engineering properties include the USCS and AASHTO classification groups which may, in turn, be used as a means of rapidly determining the general suitability of areas for proposed development, particularly during the reconnaissance investigation stages of transportation route locations and township developments, with a resultant saving of time and money. The model was verified using data from the study area, as well as from an area located approximately 190 km from the study area. A total of 88% of the classification groups determined by the model, in the study area, were correct. Furthermore, only 6% of the classifications were incorrect by a maximum of two groups. The classifications determined for the soils outside the study area were all correct.

Loess Is More: Field Investigation and Slope Stability Analysis of the Tanana 440 Landslide, Interior Alaska

ABSTRACT Landslides are geologic hazards that threaten human life, property, and infrastructure. Proper mitigation requires knowledge of where landslides occurred in the past. Until recently, no landslide inventory maps had been published for any area of Alaska. Here, we present a short overview of landslide mapping within the Fairbanks North Star Borough (FNSB), Alaska, and a focused investigation of the Tanana 440 (T440) landslide. We mapped 1,679 landslides and field-verified 51 landslides within the FNSB. These landslides vary in age, movement type, and material. We present the results of in-depth mapping; subsurface exploration; soil engineering properties, including results of direct shear testing; and slope stability analysis of the T440 landslide, which we determined is a flow slide in loess that occurred during the late Pleistocene to mid-Holocene. We modeled seven slope stability scenarios for the T440 landslide by varying water table position and seismic load. Our modeling results suggest that thawing permafrost and/or seismic loading were likely possible triggers for the T440 landslide. To our knowledge, we present the first comprehensive direct shear testing of non-plastic silt with a variation in moisture content and the first comparison of direct shear and field vane shear measurements of silt. The average cohesion and internal friction angle of the wetted remolded silt were 3.0 kPa and 23.1°, respectively. These values did not significantly change with increasing moisture content. The direct shear and vane shear strengths of silt had low correlation (R2 = 0.20), unlike the strong correlation that is typical of clay soils.

Experimental Study on the Influence of Microbial Content on Engineering Characteristics of Improved Expansive Soil

In order to study the influence of microbial content on the engineering properties of expansive soil im-proved by microbially induced calcium carbonate (MICP) method, and to clarify its influence law and mechanism of action, and to provide some theoretical reference for the application of MICP method to expansive soil treatment. Microbial reproduction and their mineralization in expansive soils have been studied. The problems such as moisture content controlling and low calcium content in the process of treating expansive soil with MICP method have been solved by means of adding calcium salt and using optimum moisture content as the control standard of the total amount of bacterial solution and cementation solution. The tests such as compaction, swelling rates and triaxial shear are carried out. The hydrophilicity, compaction, expansibility and strength characteristics of improved expansive soil under different microbial content are analyzed. The results demonstrate that with the increasing of microbial content, the dry density and shear strength of the improved soil are first increased significantly and then tend to be stable gradually. At the same time, the hydrophilicity and expansibility of improved soil are all decreased significantly. The microstructures of improved expansive soil are imaged by scanning electron microscope. Analytic results show that soil particles have been cemented and the pores in the soil have been filled due to microbially induced calcite precipitation. As a result, microstructure characteristics of the soil have been improved. From the microscopic point of view, the improvement mechanism of MICP method on expansive soil has been revealed. The conclusions above laid a theoretical foundation for in-tensive study on the improvement of expansive soil by MICP method. It also provides a new idea for perfecting and expanding the engineering application of expansive soil improvement technology.

The Use of Microbial Technology to Soil Stabilization

Microbially exacerbate existing precipitation (MICP) is an emerging technique with great potential for enhancing soil quality. The study's overarching objective is to quantify MICP's contribution to black cotton soil's improved shear strength and reduced hydraulic conductivity. The findings of a laboratory study on the influence of microorganisms on the engineering properties of soil treated with MICP. The bacteria utilized in this study was called Bacillus megaterium. A mold was made with the same interior size as the vortex shear instrument, and soil samples were then tested using this setup. The presence of microbes in black cotton soil greatly improves its shear strength and decreases its hydraulic conductivity, as shown by vane shear and penetration tests.

Industrial Waste and its Impacts on the Engineering Properties of Soil: a Review

Industrial Waste and its Impacts on the Engineering Properties of Soil: a Review

Industrial Waste and its Impacts on the Engineering Properties of Soil: a Review

This review evaluates industrial waste: its definition, components and types, and then its impact on the soil. the remarkable ‎development in industry in recent times and its progression forward led to more secondary products, which at present ‎constitute one of the most important problems facing the scientist. The researchers discuss the extent to which they can be ‎used in soil stabilization by reviewing most of the research and studies on industrial waste and soil. In addition, the ‎advantages and disadvantages of using industrial waste in treating soil problems at the lowest possible cost without ‎resorting to other alternatives. This paper also presents the role of society in reducing its environmental damage by ‎reviewing researches and studies on recyclable materials and the most applicable at present by the industry, which is a ‎suitable idea to incorporate the best-recycled materials in the construction of roads and engineering facilities. These steps ‎came after taking the processes of recycling and reusing industrial waste in many forms and methods, and according to the ‎nature and type of waste and the purpose of its reuse, in addition to the state and nature of the material with which these ‎wastes are used.‎

Standoff High-Frequency Electromagnetic Induction Response of Unsaturated Sands: A Tank-Scale Feasibility Study

Standoff electromagnetic induction (EMI) measurements of complex conductivity and complex permittivity for engineering soil properties have the potential to revolutionize the way the US Army handles route planning and infrastructure assessment. An unmanned aerial system (UAS) based EM platform for soil interrogation would have wide reaching impact in a variety of applications including: civil infrastructure inspection, in-theater ingress and egress routing, reduction of false positives in IED detection, and permafrost mapping, among many others. Traditional frequency domain EMI instruments assess conductivity at low-frequencies, generally in the range of 1–20 kHz; however, recent advancements have resulted in instrumentation targeting a broadband range of frequencies, from 10 kHz through 20 MHz. This advancement, known as high-frequency electromagnetic induction (HFEMI) allows the potential to evaluate frequency domain relaxation effects in soils by acquiring both the in phase and quadrature response of the secondary field from the soil. Relaxation phenomena such as induced polarization and dielectric permittivity are related to important soil properties that can potentially be exploited using this HFEMI system. While conductivity measurements using the quadrature component of the EMI response are well established in EMI instrumentation, understanding of the relationship between direct electrical measurements and standoff HFEMI measurements is lacking. In an effort to illuminate this relationship between various electrical and electromagnetic methods at a scale suitable for soil property estimation, we perform side-by-side measurements using galvanic geoelectrical methods (ERT, IP), electromagnetics, time-domain reflectometry (TDR) and ground penetrating radar (GPR). We compare HFEMI obtained quadrature and in-phase responses to ERT, IP, TDR and GPR measurements. A tank-scale test cell was developed for comparison of the above methods and allowed assessment of sand at varying saturation levels. Further, the HFEMI response at varying heights above the sand surface was also assessed. Qualitative observations are reported in an initial attempt to relate the HFEMI response to important soil parameters.

Macroscopic Stress-Strain Response and Strain-Localization Behavior of Biopolymer-Treated Soil.

The enhancement of soil engineering properties with biopolymers has been shown recently as a viable and environmentally benign alternative to cement and chemical stabilization. Interest in biopolymer-treated soil is evident from the upsurge of related research activities in the last five years, most of which have been experimental in nature. However, biopolymers have not yet found their way into engineering practice. One of the reasons for this may be the absence of computational models that would allow engineers to incorporate biopolymer-treated soil into their designs. Therefore, the main goal of this study is to numerically capture a macroscopic stress-strain response and investigate the effect of biopolymers on the onset of strain localization. Several diagnostic strain-localization analyses were conducted, thus providing strain and stress levels at the onset of strain localization, along with the orientations of the deformation band. Several unconfined compression and triaxial tests on the plain and biopolymer-treated soils were modeled. Results showed that biopolymers significantly improved the mechanical behavior of the soil and affected the onset of strain localization. The numerical results were confirmed by the digital image analysis of the unconfined compression tests. Digital image processing successfully captured high strain concentrations, which tended to occur close to the peak stress.

Microscopic and mineralogical characteristics behind the engineering properties of a compacted andesitic volcanic soil

Most of the volcanic soils found around the world are concentrated in regions of high demographic and economic growth. Research shows that the drying process to which volcanic soil samples are subjected to as part of the preparation process for laboratory testing can affect soil engineering behaviour, inadvertently leading to undesirable results. Previous studies suggest that the key to the understanding of the behaviour of volcanic soils lies in its mineralogy. Thus, this paper proposes an experimental investigation on an andesitic volcanic soil from Popayan, Colombia, to investigate the extent to which changes in drying affect the engineering behaviour of the soil. Mineralogical tests indicated the presence of halloysite in the soil. From the geotechnical, hydromechanical and structural tests it was possible to recognise that the drying procedure influenced: compaction behaviour; consistency limits; particle size distribution; retention behaviour; compressibility and pore size distribution (>1 μm), while not having great effect on: specific surface; pore size distribution (<1 μm). Combined analyses of the laboratory tests performed suggested that the dehydration of halloysite at mineral scale could then explain the distinct change in engineering behaviour observed when this soil is subjected to drying.

Prediction of unconfined compressive strength and California bearing capacity of cement- or lime-pozzolan-stabilised soil admixed with crushed stone waste

ABSTRACT So far, a limited number of studies have been published on utilisation of crushed stone waste, cement, lime and pozzolan as stabilisers for soil stabilisation. The research conducts soil engineering properties and strength test for various contents of crushed stone waste, cement, lime and pozzolan under various curing times. Increasing the pozzolan or cement content resulted in an increase in UCS; however, the UCS increased as the lime content increased from 0% to 5% and then decreased as lime content violated from 5%. An increase in the granite crushed stone content from 0% to 10% resulted in an increase in the UCS value. The unsoaked CBR and UCS values are almost 1.37 and 1.24 times more than the corresponding soaked ones for all cases, respectively. The CBR value increased with the increase in the pozzolan, lime or cement content. The cement content has more important influence on the increase in CBR value than the lime or pozzolan content. The multi-layer perceptron (MLP) neural network and non-linear regression (NLR) techniques are employed to develop models to predict the CBR and UCS values of the stabilised specimens.

Combined Effect of Biopolymer and Fiber Inclusions on Unconfined Compressive Strength of Soft Soil.

The utilizing of traditional chemical stabilizers could improve soil engineering properties but also results in brittle behavior and causes environmental problems. This study investigates the feasibility of the combined utilization of an ecofriendly biopolymer and fiber inclusions as an alternative to traditional cement for reinforcing soft soil. A series of unconfined compression tests were conducted to examine the combined effect of the biopolymer and fibers on the stress–strain characteristics, strength improvement, failure pattern, and reinforcement mechanism of soft soil. The results show that the biopolymer associated with fibers has an unconfined compressive strength similar to that of fiber-reinforced soil. However, it then increases with different curing times and conditions, which can be up to 1.5 MPa–2.5 MPa. The combined effect of fibers and the biopolymer is not simply equivalent to the sum of the effects of each individual material. The fiber shows its role instantly after being mixed into soil, whereas the effect of biopolymer gradually appears with sample curing time. The biopolymer plays a dominant role in increasing the peak unconfined compressive strength and brittleness of soil, while the amount of fiber is crucial for reducing soil brittleness and increasing ductility. It is shown that the biopolymer not only contributes to the particle bonding force but also facilitates the reinforcement efficiency of fibers in the soil. The fibers in return assist in reducing the soil brittleness arising from biopolymer cementation and provide residual resistance after post-peak failure.

Microstructural evaluation of the cement stabilization of hematite-rich red soil

Red soil, composed of a clayey bed containing hematite, is used as pavement material in southern Iran. As an effective and economical technique, soil improvement with cement is common practice for improving the engineering properties of different soil and pavement layers. The formation of nanostructured calcium silicate hydrate (C-S-H) is the primary factor contributing to this improvement. On the other hand, the presence and dissolution of hematite in the soil structure can also influence C-S-H formation. The present study investigates the effects of cement on the engineering properties of the hematite-rich red soil from a microstructural point of view, with particular emphasis on changes in the C-S-H nanostructure. For this purpose, red soil specimens were stabilized with 2, 4, 6, 8 and 10 wt% cement for different curing times. The soil's engineering properties were evaluated by macrostructural testing, namely by soil particle size analysis and slake durability, water absorption, Unconfined Compressive Strength (UCS), and Ultrasonic Pulse Velocity (UPV) tests. Furthermore, the soil stabilization process and the effects of hematite on the C-S-H microstructure were evaluated by pH and Electrical Conductivity (EC) tests, X-Ray Diffraction (XRD), energy-dispersive X-ray analysis (EDX), and Scanning Electron Microscope (SEM) imaging. It was shown that adding cement to hematite-rich soil promotes Calcium Ferrite Hydrate (C-F-H) and ilavite (C-F-S-H) formation and, consequently, improves the red soil's stability and compressive strength. In fact, using 6 wt% cement, the presence of hematite, and the formation of Fe-containing nanostructures helped the red soil specimen develop a compressive strength of 2.04 MPa (17 times that of the natural soil) in seven days.

Effect of Iron Oxide Coatings on Thermal Conductivity of Silica Sands

Engineering properties of soils coated with naturally occurring or artificially manufactured particles can significantly differ from those of uncoated soils. This study aims at evaluating the effect of iron oxide coatings on the thermal conductivity of silica sands. Laboratory thermal needle probe tests were conducted on uncoated, goethite coated and hematite coated Ottawa 20/30 and Ottawa 100/200 sands. Test results demonstrated that the thermal conductivity (k) of all tested materials increases with increasing applied vertical stress, and the k of hematite coated sands was greater than that of uncoated sands under the similar relative density. However, the measured k of both uncoated and coated sands is a single function of porosity regardless of applied stress level, reflecting the limited effect of applied stress and iron oxide mineral coating on the k of tested materials. Simple resistances in series model was employed to explain the observed test results, and the results of this study was compared with k of previous studies on uncoated natural soils.

Engineering Properties and Slope Inventory of Clayey Soil from the Trusmadi Formation in Bundu Tuhan, Sabah

The study area in Bundu Tuhan mainly consists of the metasedimentary rock of the Trusmadi Formation. Trusmadi Formation aged Palaeocene to Middle Eocene made up of interbedded dark grey shale and thin sandstone that shows the characteristics of deep marine sediment. Shale bed also known as phyllite unit is the major rock unit in Trusmadi Formation that is usually weathered and produced clayey soil. Clayey soil is often acknowledged as problematic soil due to its properties that tend to hold water highly compared to sandy soil, which will cause further engineering problems due to the soil creeping. The study area is prone to landslide activity, especially in the Trusmadi Formation’s slopes. Hence, this paper aims to determine the engineering properties of clayey soil from the Trusmadi Formation. Two slopes were also selected for laboratory analysis and slope inventory. The results of the analysis show that both samples are poorly sorted materials which are classified as sandy and silty clay soil and silty clay soil. The moisture content is 25.98% to 37.10%, specific gravity ranged from 2.52 to 2.57, and plasticity index ranged from 21.68% to 23.91%. The soil has inactive to a normal type of clay (0.59 to 0.97) with a very high swelling capacity (9.29% to 11.43%). The maximum dry density (MDD) ranged from 1.44 to 1.53 and optimum moisture content (OMC) of 25.47% to 25.67%. Also, both samples are classified as impermeable soil with a K value ranging from 1.74x10−8 m/s to 2.45x10−8 m/s. While, based on the slope inventory inspection, both slopes were comprised of metagreywacke, where the first slope was an embankment slope, and the second slope was a cut slope. The first slope has poor vegetation cover which leads to moderate erosion and instability that further caused failure which is rotational debris slide. As for the second slope with average vegetation cover, there is only minor erosion and instability present on the slope, and this slope also shows slow soil movement that indicates soil creep.

Experimental Investigation and Mapping of Index and Shear Behavior of Soils a Case in Gimbichu Town, Ethiopia

Objectives: To study experimental investigation on index and engineering properties of fine-grained soils by conducting laboratory tests and to prepare a soil spatial map using ArcGIS software of Gimbichu town, Ethiopia. Methods: Hence, ten test pits were selected according to the variation of the soil and the distribution of the dwellings. The soil samples were collected by direct manual excavated to 1.5m and 3.0m depth on which both laboratory and field tests were conducted for index and shear properties. Findings: Index properties revealed that soils in the study area are mostly silt soils with high plasticity and partly low plasticity. It is indicated that the soils are medium to very stiff with unconfined compressive strength of 53.70 to 216.40kPa and undrained shear strength of 26.67 to 108.20 kPa. Permeability and consolidation investigation results presented soils in the town are silt group. The spatial soil property map is created for experimentally determined results at 1.50m and 3.0m depths using ArcGIS software to retain soil properties in order to earn time and cost of the investigation in the field and laboratory. These maps are required for recognizing, identifying, and classification of soil categories within delineated parts of the current study town. Novelty: Investigation and ArcGIS spatial mapping for soil properties are essential for future boosting of the design and construction buildings of this town that was not applied before in investigation lagged areas like Gimbichu town. Keywords: ArcGIS Mapping; Experimental study; Index properties; Shear parameters; Soil class

Index And Engineering Properties Of Subgrade Soils: A Study In Areka Town, Wolaita Zone, Southern Ethiopia

Civil engineering structures are designed from the knowledge of soil properties at the given site. This research work is for the Investigation of index and engineering properties of Areka town subgrade soils. To investigate these ten test pits were selected by dividing the total area of the town in to ten parts based on the expansion potential of the town and the current distribution of the gravel road according to the municipality of Areka town. The soil samples per pit up to 3m depth, were collected from open pits by direct manual excavation. During field testing, field density and natural moisture content tests were done.[15] The laboratory tests that were carried out includes natural moisture content, particle size distribution, specific gravity, Atterberg limits (LL and PL), compaction (OMC and MDD), CBR and CBR swelling potential tests were conducted. From the results that were obtained for grain size analysis, Atterberg limits and from soil classification systems (USCS and AASHTO). According to the results of this research, Natural Moisture content ranged between 8.0-12.0%, field dry density ranged between 1.66 – 1.87( g/cc) , gravel fraction between 9.18-16.19 %, sand fraction between 22.30-54.26 %, silt fraction between 15.82-47.69 %, Clay fraction between 9.0-35.5%, Specific Gravity ranges between 2.58-2.78, Plasticity Index between 8.21- 14.61%,, GI ranges from 4 to 11 and for the soil classification under A-4, A-6, A-7-5 and A-7-6 according to AASHTO M145 and inorganic silts of medium compressibility according to unified soil classification system and the OMC ranges from 10.14% to 21.37 %, MDD ranges from 1.77 g/cc to 1.98g/cc, CBR swell ranges from 1.42- 1.92% and CBR value ranges from 6.31-8.76 (%) as the test result indicate that CBR swelling potential values were below 2%, therefore they were good to use as a subgrade soil for pavement construction [6]. The CBR values for the soil samples were above 5% so they were good to use as a subgrade soil for pavement construction [11]. From all soil samples the subgrade strength class based on CBR value TP1, TP6, TP9, TP10 were S3; and the remaining were S4 [7].; thus, the subgrade soil has good bearing capacity for the pavement construction based on [4].

Discussion: The Impact of Variation of Gypsum and Water Content on the Engineering Properties of Expansive Soil [DOI: 10.1007/s40515-021–00192-5

Discussion: The Impact of Variation of Gypsum and Water Content on the Engineering Properties of Expansive Soil [DOI: 10.1007/s40515-021–00192-5

Reply to the Discussion: The Impact of Variation of Gypsum and Water Content on the Engineering Properties of Expansive Soil [DOI: 10.1007/s40515-021–00,192-5

Reply to the Discussion: The Impact of Variation of Gypsum and Water Content on the Engineering Properties of Expansive Soil [DOI: 10.1007/s40515-021–00,192-5

Physical and engineering properties of peat soil stabilized with the admixture of CACO3+rice husk ash due to water infiltration from surrounding areas

Peat is a type of soil with high organic content, very low bearing capacity, and high uneven settlement. Some methods to improve soil have been applied to peat in order to make it strong enough for civilization-building foundation situated on it. Peat stabilization is a method that is continuously developed considering that the cost it needs is lower and this approach is more environmentally friendly compared to other methods. The admixture of lime (CaCO3) and Rice husk ash, a new ecofriendly stabilizer material, has been applied to peat soil and showed a good result. However, in studies conducted previously, the effect of water infiltration from surrounding areas of soil was stabilized was not involved as variable influencing the change of parameter. Based on that, this laboratory study was carried out to model the real condition in the field when the stabilization is performed and to identify the physical and engineering changes of peat soil in the 10th, 20th, and 30th days of stabilization in its border and middle parts, with the percentage of material stabilizer 5%, 10%, 15% and 20% of the unit weight of the initial condition of peat. The result of laboratory test shows that the addition of admixture of lime (CaCO3) and rice husk ash can improve the physical and engineering properties of peat soil are stabilized. Water infiltration occurred on peat soil is stabilized has not affected the physical and engineering properties of the soil. It can be seen from the physical and engineering properties of the border and central parts of peat soil is stabilized that still have a similar value. It is assumed to be caused by CaSiO3 gel formed still needs a longer duration to become stable gel. However, in this initial study it was known that the more stabilizers added, made the better the parameters of the stabilized peat soil.

Study of soil properties affected by leachate – A case study at Urali-Devachi, Pune, India

Landfill leachate is created via decomposition of landfill waste transported by water percolation through the soil layers. If the landfill sites are not designed properly then the leachate simply passes through the soil layers. This may create an adverse effect on the engineering properties of soil, as well as on the chemical properties viz. adsorption and retention of heavy metals. In the present study, an experimental work was carried out to examine the effects of landfill leachate contamination on the soil properties viz. physiochemical and geotechnical of an active Municipal Solid Waste (MSW) dumping site located near Pune city, India. The soil samples were collected from three different locations (at 150 m spacing) and leachate was collected from the treatment plant, located in the premises of the dumping site. The test result shows that the leachate containing the highest concentration of metals, Biochemical Oxygen Demand (BOD), and Chemical Oxygen Demand (COD). The soil sample in close proximity to the MSW dumpsite is most contaminated as compared to the furthermost soil samples, because of the high contents of organic pollutants and heavy metals. The present study clearly indicates that if the leachate is permitted to drain straightway into the surface water or infiltrates in to the groundwater it can cause adverse effect on human health and environment.