Understanding slope stability is crucial for effective risk management and prevention of slides. Some deterministic approaches based on limit-equilibrium and numerical methods have been proposed for the assessment of the safety factor (SF) for a given soil slope. However, for risk analyses of slides of earth dams, a range of SFs is required due to uncertainties associated with soil strength properties as well as slope geometry. Recently, several studies have demonstrated the efficiency of artificial neural network (ANN) models in predicting the SF of natural and artificial slopes. Nevertheless, such techniques operate as black-box models, prioritizing predictive accuracy without suitable interpretability. Alternatively, multivariate polynomial regression (MVR) models offer a pragmatic interpretability strategy by combining the analysis of variance with a response surface methodology. This approach overcomes the difficulties associated with the interpretability of the black-box models, but results in limited accuracy when the relationship between independent and dependent variables is highly nonlinear. In this study, two models for a quick assessment of slope SF in earth dams are proposed considering the MVR and the ANN models. Initially, a synthetic dataset was generated considering different soil properties and slope geometries. Then, both models were evaluated and compared using unseen data. The results are also discussed from a geotechnical point of view, showing the impact of each input parameter on the assessment of the SF. Finally, the accuracy of both models was measured and compared using a real-case database. The obtained accuracy was 78% for the ANN model and 72% for the MVR one, demonstrating a great performance for both proposed models. The efficacy of the ANN model was also observed through its capacity to reduce false negatives (a stable prediction when it is not), resulting in a model more favorable to safety assessment.

This paper addresses the issue of crack expansion in adjacent buildings caused by foundation pit construction and develops a predictive model using the response surface method. Nine factors, including the distance between the foundation pit and the building, soil elastic modulus, and density, were selected as independent variables, with the crack propagation area as the dependent variable. An orthogonal test of 32 conditions was conducted, and crack propagation was analyzed using the FEM-XFEM model. Results indicate that soil elastic modulus, Poisson's ratio, and distance between the pit and building significantly impact crack propagation. A predictive model was developed through ridge regression and validated with additional test conditions. Single-factor analysis showed that elastic modulus and Poisson's ratio of the silty clay layer, elastic modulus of sandy soil, and pit distance have near-linear effects on crack propagation. In contrast, cohesion, density, and Poisson's ratio of sandy soil exhibited extremum points, with certain factors showing high sensitivity in specific ranges. This study provides theoretical guidance for mitigating crack propagation in adjacent buildings during excavation.

Biodegradable plastic is the preferred alternative to traditional plastic products due to its high degradability, decreased dependence on fossil sources, and decreased global pollution according to the accumulation of traditional plastic. In the current study, the optimization of biodegradable plastic synthesis was studied using biomass reinforcement materials. The reinforcement material is cellulose extracted from sawdust to prepare biodegradable plastic using the casting method. Response surface methodology using Box-Behnken Design is used to optimize the main parameters affecting the tensile strength and elongation at the break of the biodegradable plastic. These parameters are cellulose fiber addition, acetic acid addition, and the mass ratio of glycerol to starch. The maximum tensile strength and elongation were obtained at 4.45 MPa and 5.24%, respectively, using 5% cellulose fiber addition and 11.24% acetic acid addition with a 0.266 w/w glycerol to starch mass ratio. Various analyses were performed on the produced biodegradable plastic, including FTIR, SEM, and thermal stability. The biodegradability of the produced biodegradable plastic after immersing the soil for 10 days was about 90% higher than the traditional plastics. The produced biodegradable plastic has a moisture content of 4.41%, water absorption of 81.5%, water solubility of 24.6%, and alcohol solubility of 0%. According to these properties, the produced biodegradable plastic can be used in different industries as a good alternative to traditional plastics.

In order to accurately model the machine-lunar soil simulant interaction, this study combined physical and simulation experiments to calibrate the discrete element simulation parameters of the JLU-H lunar highland simulant. First, the intrinsic parameters and the true angle of repose of the JLU-H were determined through physical tests to provide data for subsequent simulation tests. A Plackett-Burman test was designed to identify and select the parameters that have a significant effect on the angle of repose. The range of values of the significant parameters was then optimized using the steepest climb test. The Box-Behnken test was then utilized to calibrate and obtain the optimal parameter combinations. Finally, a validation test of the angle of repose was conducted using the calibrated DEM parameters. The relative error between the simulation results and the test results was 1.54 %. Then further straight shear tests were conducted to verify the accuracy and validity of the DEM parameters. The results show that the calibrated parameters can provide a reference for the selection of discrete element simulation parameters for lunar soil simulant and the design and optimization of drilling and excavation machinery for lunar exploration. (c) 2024 COSPAR. Published by Elsevier B.V. All rights are reserved, including those for text and data mining, AI training, and similar technologies.

This study utilizes polymers based on coal gangue and blast furnace slag to solidify engineering slurry with high silt content. Response surface methodology was employed to investigate the effects of polymer composition, alkali activator modulus, and coal gangue calcination temperature on the unconfined compressive strength of stabilized soil. Additionally, the study comprehensively characterized the thermal stability, pore structure, molecular bonds, mineral composition, and micro-morphology of the stabilized soils, and explored the mechanisms governing their strength development. The results demonstrate that the highest strength of stabilized soils is achieved with a slag to coal gangue ratio of 2.5:7.5, a water glass modulus of 1.2, and a coal gangue calcination temperature of 750 degrees C. Formation of calcium-aluminum-silicate-hydrate (C-A-S-H) and sodium-aluminum-silicate-hydrate (N-A-S-H) contributes significantly to the strength development. The presence of slag promotes early strength through C-A-S-H formation, while coal gangue facilitates N-A-S-H formation, supporting later-stage strength development by filling micropores. By applying alkali-activated calcined coal gangue-slag based cementitious materials to solidify engineering slurry, this research not only elucidates the mechanism of alkaliactivated calcined coal gangue-granulated blast furnace slag in slurry solidification but also promotes the utilization of industrial solid waste, providing new insights for environmental protection and resource recovery.

This study investigated the combined effects of calcium carbide waste (CCW) and lateritic soil (LS) on sustainable concrete's fresh and mechanical properties as a construction material for infrastructure development. The study will explore the possibility of using easily accessible materials, such as lateritic soils and calcium carbide waste. Therefore, laterite soil was used to replace some portions of fine aggregate at 0% to 40% (interval of 10%) by weight, while CCW substituted the cement content at 0%, 5%, 10%, 15%, and 20% by weight. A response surface methodology/central composite design (RSM/CCD) tool was applied to design and develop statistical models for predicting and optimizing the properties of the sustainable concrete. The LS and CCW were input variables, and compressive strength and splitting tensile properties are response variables. The results indicated that the combined effects of CCW and LS improve workability by 18.2% compared to the control mixture. Regarding the mechanical properties, the synergic effects of CCW as a cementitious material and LS as a fine aggregate have improved the concrete's compressive and splitting tensile strengths. The contribution of LS is more pronounced than that of CCW. The established models have successfully predicted the mechanical behavior and fresh properties of sustainable concrete utilizing LS and CCW as the independent variables with high accuracy. The optimized responses can be achieved with 15% CCW and 10% lateritic soil as a substitute for fine aggregate weight. These optimization outcomes produced the most robust possible results, with a desirability of 81.3%.

Caffeine, a significant naturally occurring alkaloid in beverages like tea and coffee, can be degraded by bacteria. Prolonged caffeine consumption can stimulate adrenal glands, cause irregular muscle activity, cardiac arrhythmias, and withdrawal symptoms such as headaches and fatigue. Beyond its health-related concerns, the environmental impact of caffeine degradation is noteworthy. Effluents from coffee industries contain high caffeine concentrations, and the discharge of such effluents into lakes poses a risk to the portability of drinking water. This study isolated a novel bacterium from agricultural soil, identified as Bacillus sp. KS38 through 16 S rRNA gene sequencing, which can metabolize caffeine as the sole carbon and nitrogen source. The bacterium exhibited Gram-positive characteristics. Response surface methodology (RSM) optimized bacterial growth conditions. The relevant parameter for the degradation of caffeine was obtained by first screening the parameters using the Plackett-Burman design. Using central composite design (CCD) and RSM, the important parameters were determined to achieve the ideal degradation conditions. The identified the ideal degradation conditions: 0.66 g/L caffeine, 0.85 g/L glucose, pH 6.83, and 20.5 degrees C. RSM predicted a bacterial growth of 0.591, which was confirmed experimentally. This bacterium has potential applications in wastewater treatment and caffeine bioremediation.

Globally, approximately 2.12 billion tons of waste are annually disposed of, with laboratories significantly contributing across diverse waste streams. Effective waste management strategies are crucial to mitigate environmental impact and promote sustainability within scientific communities. This study addresses the challenges by introducing a novel method that transforms laboratory media waste into a valuable biopolymer named Agastic. The process involves repurposing agar extracted from bulk laboratory waste, blending it with bio-based plasticizers to produce Agastic sheets exhibiting mechanical properties comparable to traditional bioplastics. Using response surface methodology (RSM) and central composite design (CCD), optimal concentrations of agar (1.5-2.5% w/v), glycerol (0.25-1% v/v), and ethanolamine (0.5-1.5% v/v) were determined. Predictions from Design Expert software indicated impressive tensile strength up to 14.31 MPa for AGA-1 and elongation at break up to 52% for AGA-2. Fourier Transform Infrared Spectroscopy (FTIR) analysis confirmed agarose structural features in AGA-1 and AGA-2. Thermogravimetric analysis (TGA) showed polysaccharide-related breakdown between 38 degrees C and 280 degrees C in AGA-1, peaking at 299.36 degrees C; AGA-2 exhibited diverse thermal decomposition up to 765 degrees C, suggesting their biodegradable potential in packaging applications. Scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDS) analysis confirmed nontoxic nature of Agastic and preserved morphological integrity in both samples. Soil degradation studies revealed AGA-1 and AGA-2 losing 71.31% and 70.88% of weight, respectively, over 15 days. This innovation provides a sustainable pathway to repurpose laboratory waste into eco-friendly bioplastics, particularly suitable for moisture-sensitive packaging such as nursery applications. These findings underscore Agastic films' promise as environmentally friendly alternatives to traditional plastics, supporting circular bioeconomy principles and significantly reducing ecological impacts associated with plastic waste.

The preservation of the ancient seawall site is a focal point and challenge in the protection of historical relics along Hangzhou's Grand Canal in China. This endeavor holds significant historical and contemporary value in uncovering and perpetuating Hangzhou's cultural heritage. Researchers investigating the Linping of the seawall site aimed to address soil site deterioration by selecting environmentally friendly alkali-activated slag cementitious materials and applying the response surface method (RSM) to conduct solidification experiments on the seawall soil. Researchers used the results of unconfined compressive strength tests and microscopic electron microscopy analysis, considering the comprehensive performance of soil solidification mechanisms and mechanical properties, to establish a least-squares regression fitting model to optimize the solidification material process parameters. The experimental results indicate that the optimal mass ratio of lime, gypsum, and slag for achieving the best solidification process parameters for the seawall soil, with a 28-day curing period, is 1:1.9:6.2. This ratio was subsequently applied to the restoration and reconstruction of the seawall site, with parts of the restored seawall exhibited in a museum to promote the sustainable conservation of urban cultural heritage. This study provides theoretical support and practical guidance for the protection and restoration of soil sites.

To reuse industrial solid wastes and waste clay with low liquid limit, a kind of soil solidification material by using cement, quicklime and industrial solid wastes such as ground granulated blast -furnace slag (GGBS), silica fume (SF) was developed in this study. Response surface methodology (RSM) based on central composite design (CCD) was used to design the experiment and optimize the mix ratio of GGBS, quicklime and SF under certain cement content conditions (i.e., the content ratio of cement, GGBS, quicklime, and SF was 5: 9.14: 1.7: 2.13). A soil solidification agent named O-QGS was developed to solidify waste clay with low liquid limit. To clarify the solidification mechanism of solidified soil, a series of laboratory experiments such as UCS test, water stability test, and scanning electron microscopy (SEM) test were carried out to capture the mechanical properties, water stability, and microstructure of O-QGS solidified soil and cement solidified soil. For practical purpose of O-QGS, a method for forming prefabricated pile by using O-QGS solidified soil was developed, and a method for strengthening soft foundations with prefabricated O-QGS solidified soil pile was proposed. Based on the results of load tests, the bearing capacity of prefabricated O-QGS solidified soil pile and cement high-pressure rotary jet grouting pile, as well as the composite foundations bearing capacity of prefabricated O-QGS solidified soil pile and cement high-pressure rotary jet grouting pile used for strengthening soft foundations, were analyzed. The feasibility of prefabricated O-QGS solidified soil pile used for strengthening soft foundations was verified in practice. The present study shows that the UCS of O-QGS solidified soil is 7.25 MPa at 28 days, and the water stability coefficient of O-QGS solidified soil is larger than 0.8. Compared with the method of cement highpressure rotary jet grouting pile to reinforce soft foundation, the bearing capacity of prefabricated O-QGS solidified soil pile to reinforce soft foundation is higher, and the cost can be saved by 22.4 %.