Backfill mining is a lucrative method for extracting coal buried under buildings, and water bodies, which can substantially increase the resource usage efficiency by mitigating the strata movement and surface subsidence. Its effectiveness depends on the mechanical properties of granular backfill materials. A permeability test was performed on gangue and fly ash samples under different stress levels using an original seepage test system. The variation patterns of the broken rock's internal pressure and permeability were determined. The test results indicate the weakening of the seepage effect on granular materials and a gradual reduction of washed away fly ash. The permeability values fall into the range of 3.2 x 10(-15) similar to 3.2 x 10(-13)m(-2), and non-Darcy factor is between 3.2 x 10(10) and 3.2 x 10(12) m(-1). This phenomenon was more pronounced in samples with smaller particle sizes. As the axial stress increased, the backfill material showed a decline in permeability and an increase in the non-Darcy flow coefficient. As the content of fly ash increased, the mass loss grew sharply, which occurred mainly at the early seepage stage. The results are considered instrumental in the characterization of water and sand inrush.

To address the engineering problems of road subsidence and subgrade instability in aeolian soil under traffic loads, the aeolian soil was improved with rubber particles and cement. Uniaxial compression tests and Digital speckle correlation method (DSCM) were conducted on rubber particles-cement improved soil (RP-CIS) with different mixing ratios using the WDW-100 universal testing machine. The microcrack and force chain evolution in samples were analysed using PFC2D. The results showed that: (1) The incorporation of rubber particles and cement enhanced the strength of the samples. When the rubber particles content was 1% and the cement content was 5%, the uniaxial compressive strength of the RP-CIS reached its maximum. Based on the experimental results, a power function model was established to predict the uniaxial compressive strength of RP-CIS; (2) The deformation of the samples remains stable during the compaction stage, with cracks gradually developing and penetrating, eventually entering the shear failure stage; (3) The crack and failure modes simulated by PFC2D are consistent with the DSCM test. The development of microcracks and the contact force between particles during the loading are described from a microscopic perspective. The research findings provide scientific support for subgrade soil improvement and disaster prevention in subgrade engineering.

Most gravel roads leading to rural areas in Ghana have soft spot sections as a result of weak lateritic subgrade layers. This study presents a laboratory investigation on a typical weak lateritic subgrade soil reinforced with non-woven fibers. The objective was to investigate the strength characteristic of the soil reinforced with non-woven fibers. The California Bearing Ratio and Unconfined Compressive Strength tests were conducted by placing the fibers in single layer and also in multiple layers. The results showed an improved strength of the soil from a CBR value of 7%. The CBR recorded maximum values of 30% and 21% for coconut and palm fibers inclusion at a placement depth of H/5 from the compacted surface. Multiple fiber layer application at depths of H/5 & 2 h/5 yielded CBR values of 38% and 31% for coconut and palm fibers respectively. The Giroud and Noiray design method and the Indian Road Congress design method recorded reduction in the thickness of pavement of 56% to 63% for coconut fiber inclusion and 45% to 55% for palm fiber inclusion. Two-way statistical analysis of variance (ANOVA) showed significant effect of depth of fiber placement and fiber type on the geotechnical characteristics considered. (sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic),(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic). (sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic). (sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic). (sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic). (sic)(sic)(sic)(sic),CBR(sic)(sic)7%(sic),(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic). (sic)(sic)(sic)(sic)(sic)(sic)(sic)H/5(sic)(sic)(sic)(sic)(sic)(sic),CBR(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)30%(sic)21%. (sic)H/5(sic)2H/5(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic),(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)CBR(sic)(sic)(sic)(sic)38%(sic)31%. Giroud&Noiray(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)56%(sic)63%,(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)45%(sic)55%. (sic)(sic)(sic)(sic)(sic)(sic)(ANOVA)(sic)(sic),(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic).

To investigate the effect of interface temperature on the soil-reinforcement interaction mechanism, a series of pullout tests were conducted considering different types of reinforcement (geogrid and non-woven geotextile), backfill (dry sand, wet sand, and clay), and six interface temperatures. The test results indicate that at interface temperatures of 0 degrees C and above, reinforcement failure didn't occur during the pullout tests, whereas it predominantly occurred at subzero temperatures. Besides, the pullout resistance for the same soil-reinforcement interface gradually decreased as the interface temperature rose. At a given positive interface temperature, the pullout resistance between wet sand and reinforcement was significantly higher than that of the clayreinforcement interface but lower than that of the dry sand-reinforcement interface. Compared with geotextile reinforcements, geogrids were more difficult to pull out under the same interface temperature and backfill conditions. In addition, the lag effect in the transfer of tensile forces within the reinforcements was significantly influenced by the type of soil-reinforcement interface and the interface temperature. Finally, the progressive deformation mechanism along the reinforcement length at different interface temperatures was analyzed based on the strain distribution in the reinforcement.

Subsequent crops are often sensitive to acetolactate synthase (ALS)-inhibiting herbicide residues, particularly in alkaline soils. The main objective of this study was to compare the impact of different ALS-inhibiting residual herbicides on growth of oil-seed rape (Brassica napus L. subsp. napus) and sugar beet (Beta vulgaris L.) in alkaline soil. In this regard, three experiments were conducted in Prague, Czech Republic, during 2021-2023. In spring, six herbicides (amidosulfuron, chlorsulfuron, imazamox, propoxycarbazone, pyroxsulam, sulfosulfuron) were applied at three application rates (1N - full, 0.5N - half, and 0.05N - 5 % of full). One and four months after application, half of each plot was sown with oilseed rape, and the other half was sown with sugar beet. Herbicide phytotoxicity and aboveground biomass were assessed four weeks after crop emergence. Weather conditions during experimental years, herbicides used, herbicide application rates and the period between herbicide application and crop sowing affected herbicide phytotoxicity and aboveground biomass of both crops. The most damaging effects were recorded with the application of chlorsulfuron for oilseed rape (phytotoxicity was 96-98 % at one month after 1N application) and sulfosulfuron and chlorsulfuron for sugar beet (phytotoxicity was 97-100 % and 90-100 %, respectively). Pyroxsulam caused the least damage to both the crops (average phytotoxicity was 18 %). Herbicide phytotoxicity was 3-times higher, and crop biomass was almost half as much as at the first assessment compared to the second assessment. Sugar beet was more sensitive than oilseed rape to chlorsulfuron and sulfosulfuron, especially in dry conditions, where 0.05 N rates caused biomass reduction of 20-60 % in sugar beet. Most of the tested herbicides could have residual effect that likely damages crops in rotation, particularly if a dry period occurs after the application of herbicides and/or sowing of crops.

This study systematically investigated the pore structure response of kaolin and illite/smectite mixed-layer rich clay in a reconstituted state to one-dimensional (1D) compression by first performing oedometer tests on saturated clay slurries, followed by characterising their pore structure using multi-scale characterisation techniques, with the primary objective of advancing the current understanding of the microstructural mechanisms underlying the macroscopic deformation of such clays. Under 1D loading, the volume reduction observed at the macro level essentially represented the macroscopic manifestation of changes in inter-aggregate porosity at the pore scale. It was the inter-particle pores that were compressed, despite the interlayer pores remaining stable. Two distinct pore collapse mechanisms were identified: kaolin exhibited a progressive collapse of particular larger pore population in an ordered manner, whereas illite/smectite mixed-layer rich clay demonstrated overall compression of inter-aggregate pores. Accordingly, mathematical relationships between the porosity and compressibility parameters for these two soils were proposed, with the two exhibiting opposite trends arising from their distinct microstructural features. Approaching from the unique perspective of pore structure, quantitative analysis of pore orientation and morphology on the vertical and horizontal planes demonstrated some progressively increasing anisotropy during compression. These findings provide important insights into porescale mechanisms governing clay compression behaviour and enrich the limited microporosity database in soil mechanics.

This research explores the stabilization of clay soil through the application of geopolymer binder derived from silicomanganese slag (SiMnS) and activated by sodium hydroxide (NaOH). This research aims to evaluate the effects of key parameters, including the percentage of slag, the activator-to-stabilizer ratio, and curing conditions (time and temperature), on the mechanical properties of the stabilized soil. Unconfined compressive strength (UCS) tests were conducted to assess improvements in soil strength, while scanning electron microscopy (SEM) was employed to analyze the microstructural changes and stabilization mechanisms. The results demonstrated that clay soil stabilized with SiMnS-based geopolymers exhibited significant strength enhancement. Specifically, the sample stabilized with 20% SiMnS and an activator-to-slag ratio of 1.6, cured at room temperature for 90 days, achieved a UCS of 27.03 kg & frasl;cm2. The uniaxial strength was found to be positively correlated with the SiMnS content, activator ratio, curing time, and temperature. Additionally, the strain at failure remained below 1.5% for all samples, indicating a marked improvement in soil stiffness. SEM analysis revealed that geopolymerization led to the formation of a dense matrix, enhancing soil particle bonding and overall durability. These results emphasize the potential of SiMnS-based geopolymers as a sustainable and effective soil stabilizer for geotechnical applications.

A group of earthquakes typically consists of a mainshock followed by multiple aftershocks. Exploration of the dynamic behaviors of soil subjected to sequential earthquake loading is crucial. In this paper, a series of cyclic simple shear tests were performed on the undisturbed soft clay under different cyclic stress amplitudes and reconsolidation degrees. The equivalent seismic shear stress was calculated based on the seismic intensity and soil buried depth. Furthermore, reconsolidation was conducted at the loading interval to investigate the influence of seismic history. An empirical model for predicting the variation of the accumulative dissipated energy with the number of cycles was established. The energy dissipation principle was employed to investigate the evolution of cyclic shear strain and equivalent pore pressure. The findings suggested that as the cyclic stress amplitude increased, incremental damage caused by the aftershock loading to the soil skeleton structure became more severe. This was manifested as the progressive increase in deformation and the rapid accumulation of dissipated energy. Concurrently, the reconsolidation process reduced the extent of the energy dissipation by inhibiting misalignment and slippage among soil particles, thereby enhancing the resistance of the soft clay to subsequent dynamic loading.

This paper deals with the contribution of the soil-structure interaction (SSI) effects to the seismic analysis of cultural heritage buildings. This issue is addressed by considering, as a case study, the Mosque-Cathedral of Cordoba (Spain). This study is focussed on the Abd al-Rahman I sector, which is the most ancient part, that dates from the 8th century. The building is a UNESCO World Heritage Site and it is located in a moderate seismic hazard zone. It is built on soft alluvial strata, which amplifies the SSI. Since invasive tests are not allowed in heritage buildings, in this work a non-destructive test campaign has been performed for the characterisation of the structure and the soil. Ambient vibration tests have been used to calibrate a refined 3D macro-mechanical-based finite element model. The soil parameters have been obtained through an in situ geotechnical campaign, that has included geophysical tests. The SSI has been accounted for by following the direct method. Nonlinear static and dynamic time-history analyses have been carried out to assess the seismic behaviour. The results showed that the performance of the building, if the SSI is accounted for, is reduced by up to 20 % and 13 % in the direction of the arcades and in the perpendicular direction, respectively. Also, if the SSI is taken into account, the damage increased. This study showed that considering the SSI is important to properly assess the seismic behaviour of masonry buildings on soft strata. Finally, it should be highlighted that special attention should be paid to the SSI, which is normally omitted in this type of studies, to obtain a reliable dynamic identification of the built heritage.

Drought and salt stress are two major abiotic factors significantly impacting crop growth and yield. Climate change leads to increasing drought and soil salinization issues, rising significant challenges to agricultural production. Amylases play a crucial role in enhancing the tolerance of crops to these stresses by regulating physiological and enzymatic activities. Previous study identified MeAMY1 and MeBAM3 as key genes involved in cassava starch metabolism under drought stress. To investigate their functions under drought and salt stress, MeAMY1 and MeBAM3 genes were cloned and over-expressed in Arabidopsis thaliana in the current study. Overexpression of MeAMY1 in Arabidopsis enhances amylase activities, promotes starch hydrolysis, releases soluble sugar and thus enhances osmotic balance in transgenic Arabidopsis. In the mean while, expression of BAM1 and SEX1 were depressed by MeAMY1 to maintain the protects cells closed under stress and preserved starch for adapting the stressful environments. Overexpression of the MeBAM3 in Arabidopsis can increase the expression levels of AMY3 and RVE1, promotes starch hydrolysis, releases soluble sugar from the chloroplasts to the cytoplasm and thus enhances osmoregulatory substance content, reducing stress-induced damage to antioxidant enzymes and cell membranes and improving stress tolerance. The principal component analysis further indicated that MeAMY1 and MeBAM3 overexpression lines responded similarly to drought stress, while MeBAM3 overexpression provided greater resilience to salt stress.