The objective of this study was to evaluate the suitability of steel slag as an additive to the engineering properties of weak clay soil. Different geotechnical laboratory tests were conducted on both stabilized and natural soils. Steel slag (SS) was added at a rate of 0, 5, 10, 15, 20, and 25% to the soil. Specific gravity, grain size analysis, Atterberg limit test, compaction test, free swell, California bearing ratio (CBR), and unconfined compression strength (UCS) are among the tests that were performed. The Atterberg limit test result shows that the liquid limit decreases from 90.8 to 65.2%, the plastic limit decreases from 60.3 to 42.5%, and the plasticity index decreases from 30.5 to 22.7% as the steel slag of 25% was added to the expansive soil. With 25% steel slag content, the specific gravity increases from 2.67 to 3.05. The free swell value decreased from 104.6 to 58.2%. In the Standard Proctor compaction test, the maximum dry density rises from 1.504 to 1.692 g/cm³, while optimum moisture content falls from 19.77 to 12.09%. From the UCS test, mixing 25% steel slag into the soil increases the unconfined compressive strength from 64.3 to 170.6 kPa. Additionally, the CBR value increases from 3.64 to 6.82% as 25% of steel slag is mixed with the soil. As a result, steel slag has been found to improve expansive soil properties for geotechnical applications.

The primary goal of this research is to lower the hexavalent chromium (Cr (VI)) concentration that has occurred from the growth of the tannery industry. As a result, the potential for heavy metal concentration is increasing day by day. Industrial effluent containing Cr (VI) contributes significantly to water pollution. Chromium hexavalent ion (Cr (VI)) in wastewater is extremely hazardous to the environment. It is critical to address such a condition using activated carbon derived from biomass. Adsorption is one of the most successful methods for removing hexavalent chromium from wastewater. Treated wastewater has no substantial environmental contamination consequences. The ash content, moisture content, volatile matter content, and fixed carbon content of wet coffee husk were 3.51, 10.85, 68.33, and 17.31, respectively. The physicochemical properties of coffee husk-based activated carbon (CHBAC) obtained during experimentation were pH, porosity, the yield of CHBAC, bulk density, point of zero charges, and specific surface area of 5.2, 58.4 percent, 60.1 percent, 0.71 g/mL, 4.19, and 1396 m²/g, respectively, indicating that CHBAC has a higher capacity as an adsorbent medium. For optimization purposes, the parameters ranged from pH (0.3–3.7), dose (2.3–5.7) , and contact time (0.3–3.7) hr. The quadratic models were chosen for optimization, and the value for the model was significant since it was less than 0.05, but the lack of fit model was inconsequential because it was more than 0.05. The optimum adsorption obtained with numerical optimization of Cr (VI) was 97.65 percent. This was obtained at a pH of 1.926, a dose of 4.209 g/L, and a contact time of 2.101 hours. This result was observed at a pH of 1.93, a dosage of 4.2 g/L, and a contact duration of 2.1 hours. The desirability obtained during numerical optimization was 1. Coffee husk-based activated carbon has a bigger surface area, and it has a stronger ability to absorb hexavalent chromium from tannery wastewater effluents.

Landslides pose a significant threat to infrastructure, property, and human lives in many regions worldwide, including Chira town in Ethiopia. This study presents an integrated geotechnical and geophysical investigation aimed at identifying the contributing factors to landslides in Chira town, Ethiopia, with a focus on a recent landslide event. The methodology employed a combination of geotechnical and geophysical techniques to comprehensively analyze the landslide problem. The geotechnical investigation involved a detailed analysis of the soil characteristics in the area, including the composition of fine-grained soil and the determination of cohesion and angle of internal friction through triaxial testing. The geophysical investigation utilized electrical resistivity tomography to assess the subsurface soil profile. The findings revealed the presence of a massive basaltic tertiary volcanic rock layer underlying a very low resistivity layer of sticky clay soil. Through this study, it was established that rainfall, soil type, land use, elevation, and proximity to streams, slopes, and aspects were the main factors contributing to the landslide, accounting for 22.03%, 18.89%, 15.75%, 15.46%, 10.87%, 9.7%, and 7.5% of the overall influence, respectively. Based on these findings, the study proposes a range of interventions to enhance resilience against landslides, including surface drainage, the implementation of appropriate land use management practices, and the introduction of vetiver vegetation. The integration of geotechnical and geophysical methodologies provided a comprehensive understanding of the landslide problem in Chira town. The proposed interventions aim to inform future land use planning, infrastructure development, and disaster risk reduction efforts in the region. By expanding our knowledge of the mechanisms driving landslides, this study offers valuable insights that can be utilized in similar regions facing comparable geotechnical and geophysical conditions.

The surface water is contaminated by a variety of synthetic organic and inorganic compounds, chemicals, and nutrients; due to this reason, the quality of the water resources of Ethiopia is declining at an alarming rate, resulting in severe environmental degradation. The main objective of the study was to recognize the pollution status river for the study area by physicochemical parameters and the extent of microbial environmental matrices. The experiment was conducted using a complete randomized model with three composite replicates in each site, and water samples were collected from six different sampling sites using the American Public Health Association (APHA) technique. Water quality parameters were analyzed by the standard method of examination, whereas same examination was determined on site (in situ) (pH, Temp, Conductivity, and Turbidity), whereas TSS, COD, BOD, nitrate, alkali, and orthophosphate were identified in the laboratory. The relationship between physicochemical and benthos assemblages as bio indicators of ecohydrological river water quality was investigated using Spearman’s median rank correlation. The output of the study reveals that there was a negatively significant difference in effect between the sample and all the sites of the river. Physicochemical results of the river indicate Temp (23.62), EC (101.42), nitrate (2.175), and orthophosphates (0.081) were below the standard guidelines; however, turbidity (8.41), BOD (784.5), and alkali (396.5) were above the standard. Same of the water quality values for this study were ranges within the standard, DO (5.11), and pH (7.66). The benthos assemblage communities of the ecohydrological area were more influenced by the influents, and the macroinvertebrate index of all sample sites indicates the Shannon and Simpson diversity indices; result shows that the river was lightly polluted.

Several field and model tests have been conducted to investigate the impact of pile installation on bearing capacity. However, little is known about how piles behave during installation, how they interact with the surrounding soil, and how this affects sandy soil properties. This review paper investigates the effect of pile driving on surrounding sandy soil as it compacts sandy soil near to the pile. For this purpose, various related literature was studied based on the observation of the pile installation effect on earth pressure or lateral stress, relative density, and pore water pressure in the sandy soil. A change in the deformation and stress state of surrounding sandy soil due to pile driving was presented. The installation of fully displacement piles can lead to significant stresses and deformations in the surrounding sandy soil. This is one of the main causes of uncertainty in the design and analysis of pile foundations. According to this study, the sandy soil around the pile is compacted during pile driving, resulting in lateral and upward displacement. This leads to the densification effect of pile driving on loose sandy soil. Sandy soil improvement with driven piles depends on pile shape, installation method, and pile driving sequences. This study concludes that in addition to its advantages of transferring superstructure load to deep strata, the increased relative density of loose sand, the change in the horizontal stress, and the influence of compaction on the sandy soil parameters during pile driving should be considered during pile design and analysis.

In this study, correlations are developed to predict compression index (Cc) from index parameters so that one can be able to model Jimma soils with compression index using simple laboratory tests. Undisturbed and disturbed soil samples from twelve different locations in Jimma town were collected. Laboratory tests like specific gravity, grain size analysis, Atterberg limit, and one-dimensional consolidation test for a total of twenty-four test samples were conducted. From one-dimensional consolidation tests, compressibility soil parameters (Cc and Cs) are determined. From the results of limited tests, an indicative good correlation is observed between Cc and LL, PL, and PI. However, a Poor correlation is developed between Cc and PL when related to the other parameters. The developed correlations will be important inputs in modeling Jimma clay soils with regression model and Artificial neural networks (ANN) analysis using simple index tests. In addition, the results of this study can serve as a basis for further study of such correlations on different clay soils in the country. In this study, regression analysis was used to explore the significance of individual independent (index) soil properties. Regression model and correlation of compression index for liquid limit, plastic limit, and plasticity index were obtained from the linear regression analysis and ANN. This correlation will be helpful for geotechnical engineers in developing the coefficient of compression (Cc) value of expansive/clay soil from index properties. Finally, based on the general findings of the study, suitable recommendations have been forwarded.