Geotechnical Properties Research Articles

Laboratory Evaluation of the Hydraulic Conductivity as a Function of Changes in the Particle Size of a Cubitermes Sp Termite Mound Soil Treated with Lime

This work characterizes the geotechnical properties and microstructure that served as a fundamental and more practical basis for describing the hydraulic conductivity of the lime-treated cubitermes sp termite mound soil. The results show that changes in particle size lead to a decrease in dry density and linear swelling. Permeability is strongly correlated with particle size distribution and compaction. Permeability increases up to the lime fixation point obtained at 6% of the lime content. Compaction for micropore reduction in treated soil is higher than in raw soil. The treated soil has a denser internal structure with agglomerations of dispersed clay particles. The increase in compaction energy reduces macropores and permeability, and the soil microstructure becomes homogeneous. Natural soil is highly impermeable, and soil-lime mixes are among the least draining materials. Higher values of hydraulic conductivity were obtained as a function of time. Soil and mixtures can be used in civil engineering works (earthworks). Correlations between hydraulic conductivity and particle size fractions are polylinear fits with R2 (0.962-0.993) and the Slogistic1 model with χ²(2.06E-15) for the mean silt fraction. This study is decisive for predicting hydraulic conductivity from the geotechnical properties of the soil, by solving the mathematical expressions of the models used.

Engineering geological map of the riverfront in the old city of Mosul

The local and central governments focused on the right side of Mosul for urban development, especially after the destruction that occurred during its liberation. The view of the study area on the river and the green spaces on the other side of the river drew the attention of the Municipality of Mosul to develop it into a tourist attraction that reflects the cultural aspect of this ancient city. 26 exploratory boreholes were drilled in the study area, with depths ranging from 10 to 20 meters, and their geotechnical specifications were determined. In this study, the Pearson correlation coefficient was used to identify the parameters that have the greatest influence on the geotechnical specifications of the layers and to classify the engineering classes. Interpolation was used in Arc GIS to compare the distribution of geotechnical properties in the three layers at depths of (3, 6, and 9 m) and to calculate the average values of geotechnical properties from a depth of (1.5 - 9 m). The specifications were classified into five classes using a classification of the different characteristics. Geotechnical maps of the study area were created to show the distribution of engineering properties and their classification into isotropic zones, allowing each application zone to be provided with the appropriate building type. The results revealed that the northwestern part of the area is best suited for towering structures, while the rest of the neighborhoods were considered less suitable.

Surface movement detection and stability evaluation of a loose fine‐grained soil slope during reservoir operation: A case study in NE reservoir

AbstractLandslide in reservoirs imposes challenges to reservoir operation and dam safety management practices. The understanding of the landside mechanism during reservoir operation is crucial to landslide‐related risk migration. During the reservoir operation from 2018 to 2021, a massive landslide occurred with over 107 m3 in total volume on the bank of the NE reservoir. The surface movement characteristics before and after the occurrence of landslides in the NE reservoir in the region scale were detected and interpreted by Sentinel‐2 time series images. Experimental studies were conducted to investigate the geotechnical properties of the fine‐grained soil. The slope stability was evaluated for a typical slope profile considering the rising water level using the extended Bishop's simplified method, which was implemented in the code STAB‐UNSAT. It can be found that the landslide in the fine‐grained soil occurred simultaneously when the water level rose. The cumulative area of soil slope failure on the left bank of the NE reservoir increased continuously during the reservoir operation from 2018 to 2020, especially had a remarkable increment from August to October in 2019. The extended Bishop's simplified method provides a more rational method to evaluate the soil slope stability. The slope failure mechanism of the studied soil, that is, collapse–erosion–slide upon the rising reservoir water has been proposed.

Geotechnical Properties of the Soil Contaminated with Medical Waste: A Case Study of Metronidazole and Amoxicillin Waste

Geotechnical Properties of the Soil Contaminated with Medical Waste: A Case Study of Metronidazole and Amoxicillin Waste

A comprehensive review on Exploration and Production scenario of Natural Gas Hydrate

Gas hydrates have emerged as a highly focused area of study over the past two decades due to their distinctive advantages and potential applications. Among gas hydrates, methane hydrates stand out for their enormous energy potential, serving as both an energy resource and finding utility in various applications such as gas storage, separation and enrichment. This study discusses the extraction of gas hydrates, which involves employing different methods such as depressurization, thermal stimulation and inhibitor injection to dissociate the compounds. Ensuring the safety and efficiency of gas production requires a comprehensive understanding of the geotechnical properties of hydrate reservoirs. It is essential to maintain flow assurance, sediment formation integrity and wellbore stability for secure and efficient extraction of gas from hydrates in sedimentary deposits. The key factors that influence these aspects, encompass strength and deformation characteristics, fluid migration behaviour and thermal conduction properties.

Mapping, impacts, characterization and extent of acid sulfate soils in Finland

Acid sulfate soils (ASS) cause big problems worldwide due to their potential to form sulfuric acid during oxidation of sulfidic materials, resulting in very acid soil (pH <4.0). Impacts include acidification of soil and water, leaching of metals, decreased nutrient supply, deterioration of water fauna and flora, and corrosion of infrastructure. These soils also exhibit poor geotechnical properties. Finland has the largest occurrences of ASS in Europe, mainly along the coast of the Baltic Sea. The EU Water Framework Directive brought about wide co-operation to reduce the harmful impacts of ASS in Finland. One urgent step was to localize and characterize the occurrences of ASS. The more than 10 year-long programme, led by the Geological Survey of Finland (GTK), started in 2009 and field work was completed in 2021. During the programme observations, measurements, sampling and analyses were made at 23 000 sites in an area of 5 010 000 ha. Traditionally ASS in Finland have been considered to comprise fine-grained sulfidic sediments and/or their oxidized layers, occurring on agricultural land along the coast below the highest shoreline of the Littorina Sea transgression. This study recognized and classified significant occurrences of other types of potentially harmful ASS materials: (1) coarse-grained ASS (sand), (2) organic ASS (peat) and (3) unsorted ASS (till material). The methods, definition and classification of Finnish ASS have been revised. We calculated the extent of ASS along the coast to be about 1 000 000 ha corresponding to 21% of the area covered in the past by the Littorina Sea, and three to six times more than earlier estimates. In addition, some occurrences of ASS were recognized inland, mainly related to black shales and sulfidic ores. The mapping data can be accessed via the GTK map service (www.gtk.fi) providing information about the distribution and properties of ASS.

Effect of collated fly ash, GGBS and silica fume on index and engineering properties of expansive clays as a sustainable landfill liner

The effect of supplementary cementitious materials (SCMs) such as fly ash (FA), GGBS and silica fume (SF) on the geotechnical index and engineering properties of expansive clays (EC) are studied in this research work. This manuscript aims to determine the workability (consistency limits (CL)), swellability (free swell index (FSI)), compaction properties, strength characteristics (UCS) and hydraulic conductivity (HC) of varied eighteen mix proportions of FA-EC (P-series), FA-GGBS-EC (Q-series) and FA-GGBS-SF-EC (R-series) are experimentally studied as a bottom liner in landfills. From the test results, CL and FSI significantly decreased in P, Q and R series, this is due to the effect of flocculation, a process that increases the average particle size of mix blends and also depletion of the double-diffusive layer thickness of EC by promoting the Ca2+ ions in the pore water from SCMs. The compaction parameters such as optimum moisture content decreased in all the series, due to the higher flocculation of mixes. However, maximum dry unit weight increased in Q and R and decreased in the P series. The UCS values increased with an increase in optimum SCMs quantities and with curing intervals tested at 0, 7, 14 and 28 days. The higher UCS value is attained at 40 %FA with EC (i.e. P2), 60 %FA-GGBS with EC (i.e. Q3) and 60 %FA-GGBS-SF with EC (i.e. R3) in R-series which confirmed to be optimum due to the loss of cementation action/reduced cohesion in the matrix. In the case of HC, P2, Q3 and R3 mixes are confirmed to be optimum and fall under the criterion standards of landfill liner as per USEPA recommendation. Overall, this work proves to be a novelty and shows the feasibility of various collated SCMs blended with EC as landfill liner material, furthermore, these mixes are optimized to combine with EC to create a sustainable landfill liner that fits with the United Nations sustainable goals of 2030

Mitigation of Fugitive Gas Emissions from Landfill Using Biochar-Amended Soil Cover and Its Geotechnical Characterization

Landfills with gas collection systems often struggle to capture fugitive emissions through the final soil cover, leading to significant environmental challenges. Considering recent major landfill fires in India, methane gas emissions have been identified as the primary cause. This research explores the potential of biochar-amended soil covers as an alternative solution to mitigate fugitive emissions. Various percentages of biochar were added to the soil collected from a landfill site in Vilholi, Maharashtra, India. Geotechnical testing assesses compaction characteristics, hydraulic conductivity, and shear strength. Amendment improves the compaction characteristics of soil cover. The decreased hydraulic conductivity with amendment indicates improved water retention. The interlocking between soil and biochar and the specific type of biochar influences the strength gained. The column setups containing different percentages of amended soil showed reduced emissions. The improved geotechnical properties and reduced fugitive emissions demonstrate the potential for biochar-amended soil covers to enhance landfills' stability.

Alkali-activation of agro-industrial waste for stabilization of lateritic soils

This paper focuses on enhancing the geotechnical properties of lateritic gravelly soil (LGS) through chemical stabilization using an alkali-activated binder produced with sugarcane bagasse ash (SBA) and a sodium hydroxide (NaOH) solution. For this, mechanical strength tests, specifically unconfined compressive strength (qu), and durability tests, including accumulated loss mass (ALM) and volumetric variation (ΔV), were conducted on compacted specimens of the LGS-SBA blends. These specimens were molded with varying concentrations of NaOH solution (ranging from 3 to 10 Molarity) and different SBA content (ranging from 3 to 10 %). The physical–chemical characteristics of the optimal blend were further analyzed through Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray Spectroscopy (EDS). The results demonstrate that the stabilization of LGS with an alkali-activated binder modifies compaction properties and enhances the mechanical strength and durability of LGS. Hence, a good correlation between qu and ALM was established, enabling the formulation of practical engineering equations to predict the behavior of the blends. Based on the results, it can be concluded that the stabilized LGS exhibits promising potential as an alternative geomaterial for use in subbase/base layers for pavements exposed to harsh climatic conditions in the low-lying Amazon region.

Experimental Assessment of Geotechnical Properties of Nano-Clay-Stabilized Soils: Advanced Sustainable Geotechnical Solution

Experimental Assessment of Geotechnical Properties of Nano-Clay-Stabilized Soils: Advanced Sustainable Geotechnical Solution

Site-Specific correlation between geotechnical and geoelectrical properties of soil deposits in India

The combined application of geotechnical and geophysical methods provides an effective means of subsurface exploration. The insufficient correlation between geotechnical and geophysical methods prevents the conversion of geophysical data to geotechnical information and vice versa. In the present study, a correlation has been proposed between the geotechnical and geoelectrical properties of two soil deposits in India. Eleven boreholes along with a Standard Penetration Test (SPT) and different laboratory tests have been conducted to obtain the different engineering and physical properties of the soil layers. Twelve Electrical Resistivity Tomography (ERT) profiles have also been conducted to obtain the resistivity profile of the subsurface layers. The variation of the resistivity of the soil layers is analyzed and explained. Results show a strong linear correlation between resistivity and SPT blow counts (N′) of the soil layer for one site while a weak correlation for another site. A strong linear correlation between transverse resistivity (T) and N′ values has been observed for both sites. A comparison with the other existing correlation between resistivity/transverse resistivity and N′-values has also been presented. The range of resistivity values and engineering properties of soil layers are mentioned. The study is useful for the development of similar correlations and provides an approximate estimation of different geotechnical parameters for infrastructure design.

Geotechnical Properties of Sand-Asphalt for Use in Road Base Layer Instead of Conventional Materials

The study of the geotechnical properties of sand-asphalt for use in road base layer instead of conventional materials, for low to moderate traffic volume, is based on standardized laboratory tests. Sand samples were taken from Kayar, Darou Alpha and Keur Morry (Thies region, Senegal). Identification tests (particle size distribution and sand equivalent) made it possible to select Kayar and Darou Alpha sands which have respective sand equivalent (ES) values of 92 % and 62 %. These values are higher than the minimum required (40 %), for sand-asphalt, with different 35/50 bitumen dosages. The results of the Hubbard-Field test carried out showed that Darou Alpha sands are suitable, with an optimum dosage of 7 % bitumen : the stability at 18 °C, at dry conditions, is 2 732 kg and is greater than the minimum required value of 2 300 kg; the immersion/compression ratio is 85 % and is greater than the minimum required limit of 75 %; water absorption reaches 5.4 % and remains below the maximum required limit of 7 %; the volumetric swelling is 2.6 % and is below the maximum required limit of 5 %. The compactness is 84 % and is acceptable because it exceeds the minimum required limit of 80 %. The sizing carried out with the Alizé©3 software gives deformation values lower than the permissible values. The pavement structure that is placed on a PF3 type platform is therefore correctly sized to support a traffic of 150 heavy vehicles per day for a service life of 15 years. This roadway structure, which is devoid of a foundation layer, includes a 23 cm thick sand-asphalt base layer on which rests a 5 cm thick asphalt concrete. Keywords: sand-asphalt, Hubbard-Field test, Kayar, Darou Alpha, Keur Morry.

Relating Geotechnical Sediment Properties and Low Frequency CHIRP Sonar Measurements

Low frequency acoustic methods are a common tool for seabed stratigraphy mapping. Due to the efficiency in seabed mapping compared to geotechnical methods, estimating geotechnical sediment properties from acoustic surveying is attractive for many applications. In this study, co-located geotechnical and geoacoustic measurements of different seabed sediment types in shallow water environments (<5 m of water depth) are analyzed. Acoustic impedance estimated from sediment properties based on laboratory testing of physical samples is compared to acoustic impedance deduced from CHIRP sonar measurements using an inversion approach. Portable free fall penetrometer measurements provided in situ sediment strength. The results show that acoustic impedance values deduced from acoustic data through inversion fall within a range of ±25% of acoustic impedance estimated from porosity and bulk density. The acoustic measurements reflect variations in shallow sediment properties such as porosity and bulk density (~10 cm below seabed surface), even for very soft sediments (su < 3 kPa) and loose sands (~20% relative density). This is a step towards validating the ability of acoustic methods to capture geotechnical properties in the topmost seabed layers.

Utilization of Earthquake Demolition Wastes and Afşin–Elbistan Fly Ash for Soil Improvement after the Kahramanmaraş Earthquake (6 February 2023)

Türkiye is surrounded by active faults that have the potential to produce big earthquakes. Recently, one of these faults has become active. Two earthquakes of magnitude 7.7 and 7.6 occurred 9 h apart on 6 February 2023 in Kahramanmaraş. It is reported that 150 million tons of earthquake demolition waste (EDW) is estimated to be produced as a result of those natural hazards. This waste poses a serious risk to both the environment and human health. Its use in geotechnical applications will provide serious environmental benefits. In this study, Afşin–Elbistan fly ash (AEFA) and EDW were used to stabilize weak clayey soils in different proportions. Samples were prepared by separately adding 5, 10, 15, and 20% AEFA and EDW to high-plasticity clay. The AEFA used in this study was used because the production of AEFA is too high, and it is not used in concrete production because it does not comply with the standards and causes serious environmental problems for the region. The Atterberg limit, standard compaction, unconfined compression strength (UCS), triaxial, and California bearing ratio (CBR) tests were performed on soil samples, and samples were prepared from soil mixtures with various proportions of AEFA and EDW added. In addition, clay mixtures were prepared with EDW by keeping the AEFA ratio constant at 15% and their effects were also investigated. According to Atterberg test results, the natural soil class was determined as high-plasticity clay, the soil class of the mixtures created by adding EDW and AEFA was determined as low-plasticity clay, and all ternary mixtures were determined as low-plasticity silt. In addition, the maximum dry density increased for all mixtures, while the optimum water content decreased. A significant increase was observed in UCS test results, especially in ternary mixtures. While cohesion increased in AEFA mixtures, it decreased in ternary mixtures as the EDW ratio increased. It was observed that the internal friction angle increased in all mixtures. According to CBR test results, it was determined that the binary AEFA mixture ratio was 20%, the binary EDW mixture ratio was 10% and above, and all ratios of the ternary AEFA + EDW mixtures could be used as road sub-base material. After the major earthquake disaster, the use of EDW is of great importance for the environment. As a result, AEFA and EDW were found to enhance the geotechnical properties of clay.

Cohesion and shear strength of compacted lunar and Martian regolith simulants

Shear strength and cohesion of granular materials are important geotechnical properties that play a crucial role in the stability and behavior of lunar and Martian regolith, as well as their terrestrial analog materials. To characterize and predict shear strength and cohesion for future space missions, it is also important to understand the effects of particle size distribution and density on these fundamental geotechnical properties. Generalized equations have been established using empirical data from direct shear measurements of lunar and Martian regolith simulants to quantify the effects of particle size distribution and density on cohesion and shear strength. Preliminary results are also presented highlighting the effects of atmospheric absorbed water on shear strength and cohesion when conducting experiments in atmospheric conditions on Earth. The results of this study show that cohesion increases exponentially with bulk density, while the exponential growth constant is also dependent on particle size distribution. The presence of absorbed atmospheric water can also produce non-monotonic effects on the shear strength of regolith, and it's influence on shear strength varies based on sample density for Earth-based experiments and applications. Together, these results highlight the importance of particle size distribution, bulk density, and atmospheric water content on the shear strength and cohesion of lunar and Martian simulants. This study also establishes generalized equations for predictive, testing, and modeling efforts for future space missions.

Importance of geotechnical soil properties for precision Forest activities in a karst area

Some soil behaviors change significantly as water content varies over time. The particle size distribution of soils has a direct impact on mechanical properties such as soil water content, resistance to dispersion, swelling-shrinkage, fluidity, plasticity, and stickiness. This study was conducted to investigate the usability of Atterberg limits, consistency index and coefficient of linear extensibility (COLE) in the temporal planning of ecosystem restoration activities such as silvicultural interventions, tillage, afforestation, and the construction of forest roads, etc. Surface soil samples were collected from the sections numbered 263, 264, 266, 268, 317, 318, 319, 323, 324,325 and 366 of the degraded forest of the Andırın forestry operations department. The COLE, liquid limit (LL), plastic limit (PL), plasticity index and consistency index values of soil samples were determined. The LL values ranged from 17.5 to 62.4%, the PL values from 8.2 to 46.8% and the PI values from 6.4 to 15.5. The highest COLE value (0.13) was recorded in the section 318, while the lowest COLE value (0.03) was in section 325.The LL and PL values have a positive linear relationship with clay and organic matter content. All sections have karstic characteristics, but the mechanical characteristics of the soils differ significantly between the sections. Silvicultural interventions carried out especially in section 318, which had the lowest consistency index (Ic = 0.70), and sections 263, 264, 317 and 319, where the consistency index is >2,should take mechanical properties into account, and the planting time intervals should be determined, accordingly for sustainable forestry.

The Implications of Geotechnical Properties of Soil in the Development of Gully Erosion in Ukpor, Southeastern Nigeria

Gully erosion is a devastating form of soil degradation threatening environmental sustainability, socio-economic development, and human well-being worldwide. The Southeastern region of Nigeria, particularly Ukpor, is prone to gully erosion, which has resulted in the loss of infrastructure, agricultural land, and human settlements. While various factors contribute to gully erosion, the soil’s geotechnical properties remain an important aspect that has been given limited attention. This study investigates the implications of geotechnical properties of soils in the development of gully erosion in Ukpor. A comprehensive approach was adopted, combining drone-aided geologic field mapping, laboratory tests and spatial analysis. Soil samples were collected from different locations at 0.5 – 1m depth, and laboratory tests (Particle Size Distribution (PSD) and Atterberg Limits) were conducted to determine the soil’s geotechnical properties. The results reveal that the study area is underlain by the Ogwashi-Asaba formation. From the Particle Size Distribution and Atterberg Limit tests, the soils in the area were classified into 3; Group A (coarse-grained clayey sands), Group B (coarse-grained poorly graded to clayey sands) and Group C (poorly-graded coarse-grained sands). The Plasticity Index (PI) of Group A ranges from 13.4 – 18.2 while the Liquid Limit (LL) ranges from 27.8 to 34.9. The PI of Group B ranges from 15.49 to 17.35 while the LL ranges from 30.7 to 35.7, From the results, Group C soils were most affected by gullying. Given the above, the underlying soil strata of Ukpor metropolis could be classified as low plasticity soil, thus, highly susceptible to erosion. The results show a significant correlation between soil geotechnical properties and gully erosion susceptibility. The results have pivotal implications for soil conservation, sustainable land management, and infrastructure development in Ukpor and similar regions. The study recommends soil stabilization techniques and vegetation management strategies to mitigate gully erosion.

Multivariate probabilistic assessment of a regional database in Copenhagen

Extensive research has been carried out to establish empirical equations between two geotechnical properties and in spite of the increase in correlation studies, a construction of a multivariate distribution function of more than two parameters is still rare. The objective of this study is to investigate the possibility of constructing two multivariate distribution functions, each consisting of 5 geotechnical parameters based on a) triaxial and soil classification tests and b) oedometer and soil classification tests in stiff over-consolidated clay till from Copenhagen. For this purpose, laboratory measurements from twenty-six sites in Copenhagen are utilized and two multivariate databases are constructed. The correlations among the ratio of deviatoric and mean effective stresses (q/p´), over-consolidation ratio (OCR), secant modulus at reference stress 100 kPa (E50ref), initial void ratio (eo) and liquid limit (LL) are investigated in multivariate model A, while multivariate model B demonstrates the correlations among oedometer modulus at 100 kPa reference stress (Eoed(ur)ref), over-consolidation ratio (OCR), permeability change index (Ck), initial void ratio (eo) and liquid limit (LL). The Nataf transformation model is used for the construction of the multivariate distributions, which are then used to simulate the correlations between geotechnical properties by generating artificial samples. Finally, the artificial samples are compared with the original database for an initial validation of the model. The constructed multivariate models obtained as a result of this study can act as prior for Bayesian updating in multivariate distribution functions when additional geotechnical tests are carried out.

Experimental evidences of bio-chemo-mechanical processes in contaminated sediments

The research shows the results of a micro to macro testing programme carried out on contaminated marine sediments from a natural deposit to assess the effects of bio-chemo-mechanical coupled processes which may act in complex natural environments and affect the geotechnical properties of the clays. The research has been triggered by the emblematic case of the contaminated Mar Piccolo (MP) basin in Taranto (Southern Italy), where the high degree of pollution recorded in the clayey sediments at the sea bottom, has been found to worsen water quality and promote bioaccumulation of pollutants in several species. Several samples of sediments collected in the basin from the top layer exhibited peculiar geotechnical properties, in terms of plasticity and activity indexes, compressibility and hydraulic permeability. The results of the geotechnical testing were interpreted taking into account the XRD mineralogical results and the chemical composition of the soil matrix. Furthermore, thermogravimetry tests results were examined to explore the nature of the sediment skeleton and of its organic matter content, based on the main thermal reactions occurring within different temperature ranges. Lastly, scanning electron microscopy and mercury intrusion porosimetry were performed to assess the sediment pore size distribution as well as their content in microfossils and diatoms. The original multiscale analysis carried out on some selected sediment samples showed that the biogeochemical degradation of organic matter and the presence of microfossils and diatoms significantly affect the micro to macro behaviour of marine sediments.

Effect of different vegetation roots on mechanical properties of soil stabilization on slope

Soil bioengineering is concerned with the soil stabilisation with the reinforcing agent such as plant roots. This approach is extensively popular in developing countries. Most of the study conducted on soil bioengineering is carried out by ecological researchers, whereas there have been few geotechnical research studies in India that focus on using plant roots for reinforcing purposes. This research aims to investigate the changes in soil strength caused by landslides. The soil will be stabilised using plant roots from regionally common plants in the study region. The lemon roots were collected and planted in the soil, and the alterations in geotechnical properties were investigated. The reinforcing process can result in an increase in the values of MDD, UCS, SS, and OMC due to the improved compaction of soil particles. It was found that as the percentage of plant root added to the soil increases, the MDD, UCS, SS, and OMC also increases until 1% of plant root was added by weight. After that point, these properties decreases. Hence, the most favourable proportion for soil stabilisation is 1% of plant root by weight to the soil. Thus the presence of plant roots in the soil matrix enhanced the soil's stability. Therefore, the plant roots that were examined can serve as cost-effective materials for enhancing slope stability,” particularly in places that are susceptible to landslides.