Expanded Polystyrene (EPS) granular lightweight soil (ELS) is an eco-friendly material made of EPS particles, cement, soil, and water. This study investigates the modification of ELS using a silane coupling agent (SCA) solution to improve its performance. Various tests were performed, including flowability, dry shrinkage, unconfined compressive strength (UCS), triaxial, hollow torsional shear, and scanning electron microscopy (SEM) analysis, to evaluate the physical and mechanical properties at different SCA concentrations. The results show that the optimal SCA concentration was 6%, improving flowability by 13% and increasing dry shrinkage weight by 4%. The UCS increased with SCA concentration, reaching 266 and 361 kPa after 7 and 28 days, respectively, at 6% SCA. Triaxial and shear tests indicated improved shear strength, with the maximum shear strength reaching 500 kPa, internal friction angle rising by 4%, and cohesion reaching 114 kPa at 6% SCA. Hollow torsion shear tests showed that 6% SCA enhanced stiffness and resistance to deformation, while reducing the non-coaxial effect. SEM analysis revealed that SCA strengthened the bond between EPS particles and the cement matrix, improving the interfacial bond. This study highlights the potential of modified ELS for sustainable construction.

Setting an expandable polystyrene (EPS) board on box culverts can reduce the vertical earth pressure (VEP) acting on the culvert roof. However, long-term backfill load will induce creep in both the EPS board and the surrounding soil, resulting in a change in the stress state of the culvert-soil system. A mechanical model for the long-term interaction of backfill-EPS board-box culvert was established, and theoretical formulas were derived for calculating the earth pressure around the culvert. Numerical simulation was employed to validate the accuracy of the proposed theoretical approach. Research indicates that, with EPS board, the VEP decreases rapidly then slightly increases with time and eventually approaches an asymptotic value, ultimately decreasing by 33%. However, the horizontal earth pressure (HEP) shows the opposite pattern and ultimately increases by 15%. The foundation contact pressure (FCP) increases nonlinearly and reaches a stable value, ultimately increasing by 10.2%. Without the EPS board, the VEP and HEP are significantly different from those with the EPS board. Although EPS boards can reduce the VEP on the culvert, attention should be paid to the variation of HEP caused by the creep of the EPS board and backfill.

Local site conditions recognized as a determining factor in assessing the extent of seismic hazard and damage distribution during earthquakes. Present study emphasizes seismic hazard of international business corridor of Agartala town capital of Tripura, one of the northeastern state of India categorized as highest seismic zone (zone V) attributing seismic response of local subsoil deposits under site-specific scenario earthquake motions including liquefaction susceptibility prediction. One-dimensional nonlinear ground response analysis with input of geotechnical parameters was carried using DEEPSOIL (2018) program across central zone of Agartala city and liquefaction susceptibility analysis are performed based on standard penetration test (SPT) utilizing well-established empirical relationship. The novelty of results lies in use of site-specific dynamic parameters of subsoil and synthetic ground motions based on scenario earthquake. Besides, numerical model was validated with a recent past liquefaction case study in Tripura which also attributes key highlight of this study. Key seismic hazard parameters in the form of peak ground acceleration (PGA), amplification factor (Af), and predominant frequencies (fn) are presented through geographical information based spatial maps. These maps provide crucial inputs for planners and designers for future urban planning along with seismic strengthening of existing infrastructures. This comprehensive approach offers new perspectives on seismic hazard assessment and future management plan in this region.

Bamboo charcoal (BC) was utilized as a modifier to functionalize poly (L-lactide-co-epsilon-caprolactone) (PLCL) in this research. Five types of BC/PLCL composite films with varying BC content (0.5 wt%, 1.0 wt%, 1.5 wt%, 2.0 wt%, and 2.5 wt%) were fabricated and subjected to degradation studies in soil. The degradation performance of these composite films was assessed by analyzing changes in apparent morphology, micromorphology, mass loss, molecular weight, and mechanical properties after 20, 40, 60, and 80 days of degradation. Results indicated a gradual increase in the degradation level of PLCL over time, accompanied by a decrease in elongation at break from 273.5 % to 12.01 %. The incorporation of BC was found to decelerate the degradation of PLCL, leading to a delayed degradation process as the proportion of BC increased.

Near-fault impulse earthquakes induce complex dynamic responses in bridge structures, potentially resulting in significant structural damage. On May 22, 2021, a magnitude 7.4 earthquake struck MaDuo County in the Guoluo Autonomous Prefecture of Qinghai Province, with the Yematan Bridge sustaining the most extensive damage during this seismic event. This study employs synthetic near-fault impulsive ground motions and the LS-DYNA explicit dynamic analysis software to investigate the mechanisms underlying the observed seismic damage and the subsequent failure of girders. The simulations effectively replicated the collisions involving the main girder, the damage to the shear keys, and the falling girders. Furthermore, post-earthquake soil exploration data, analyzed using DEEPSOIL site analysis software, are integrated to assess the amplification effects of ground vibrations at the bridge site. The analysis revealed that the longitudinal peak ground acceleration (PGA) experienced by the Yematan Bridge is approximately 6.8m/s(2), while the transverse PGA is about 4.2m/s(2). The damage to the bridge occurred in two distinct stages: initially involving collisions between the shear keys and the main girder, followed by a domino effect, leading to the failure of multiple girders. The primary factors contributing to the structural damage included impulsive seismic forces, short pier heights, transient bearing failures, and substantial longitudinal and transverse displacements of the main girder due to ground vibrations and inertial effects, which ultimately resulted in shear key damage and the subsequent collapse of girders. Despite the Yematan Bridge being designed to withstand seismic intensity rated at VIII, DEEPSOIL's inversion analysis indicated a bedrock PGA of 4.26m/s(2) and a corresponding seismic intensity of IX. At the same time, the earthquake-resistant rating for MaDuo County is designated as VIII. This discrepancy in seismic intensity zones significantly exacerbated the severity of the girder failures. The numerical findings and conclusions presented in this study provide critical insights for the seismic design of simply supported highway bridges located in near-fault regions.

This study investigated the small-strain dynamic properties of expanded polystyrene (EPS) lightweight soil (ELS), a low-density geosynthetic material used to stabilize slopes and alleviate the subgrade settlement of soft soil. Resonant column tests were conducted to evaluate the effects of EPS's granule content (20-60%), confining pressures (50 kPa, 100 kPa, and 200 kPa), and curing ages (3 days, 7 days, and 28 days) on the dynamic shear modulus (G) of ELS within a small strain range (10-6-10-4). The results indicate that ELS exhibits a high dynamic shear modulus under small strains, which increases with higher confining pressure and longer curing age but decreases with an increasing EPS granule content and dynamic shear strain, leading to mechanical property deterioration and structural degradation. The maximum shear modulus (Gmax) ranges from 64 MPa to 280 MPa, with a 60% reduction in Gmax observed as the EPS granule content increases and increases by 11% and 55% with higher confining pressure and longer curing ages, respectively. A damage model incorporating the EPS granule content (aE) and confining pressure (P) was established, effectively describing the attenuation behavior of G in ELS under small strains with higher accuracy than the Hardin-Drnevich model. This study also developed an engineering testing experiment that integrates materials science, soil mechanics, and environmental protection principles, enhancing students' interdisciplinary knowledge, innovation, and practical skills with implications for engineering construction, environmental protection, and experimental education.

Focusing on a T-shape cantilever retaining wall in a liquefiable site, a series of shaking table model tests were conducted to investigate the seismic stability characteristics of the wall when using EPS composite soil isolation piles (WEP), EPS composite soil isolation walls (WEW), and backfilled natural fine sand from Nanjing (WSS). The seismic response characteristics of the model ground soil and the retaining wall for the three models were comparatively analyzed regarding the acceleration, displacement, dynamic earth pressure and excess pore water pressure ratio. Moreover, the seismic performance of anti-liquefaction measures in the liquefiable ground with EPS composite isolation structures were discussed from the view of the phase characteristics and energy consumption. The results indicate that under the same peak ground acceleration, the excess pore water pressure in the WEP and WEW models is significantly lower than that in the WSS model. Different from WSS, WEP and WEW exhibit a segmented distribution with the buried depth in acceleration amplification factors. The embedding of isolation structures in liquefiable sites can reduce the wall sliding and rotational displacements by approximately 25%-50%. In addition, the out-of-phase characteristics of dynamic earth pressure increment are evidently different among WEP, WEW and WSS. There is an approximate 180 degrees phase difference between the dynamic earth pressure behind the wall and the inertial force in the WEP and WEW models. EPS composite soil isolation structures show good energy dissipation characteristics, and especially the isolation wall is better than isolation pile. The displacement index of WSS retaining wall is significantly larger than that of WEW and WEP, indicating that EPS composite isolation piles and wall play an important role in the mitigating damage to the retaining wall. This study can provide references for the application of isolation structures in the liquefiable ground soil regarding the seismic stability.

Unlike the Himalayas, the sub-Himalayan zones did not experience snowfall and thus suitable for growing solanaceous vegetables. However, several cold waves have been reported to affect the district of Coochbehar (West Bengal, India), which belongs to the Cwa zone (as per Koppen's classification). Variable duration of sub-optimal soil temperature can have a detrimental effect on the growth of seedlings. Our previous study demonstrates that a constant temperature of 20 degrees C (6 degrees below the optimal soil temperature) causes a 71% loss of vigor in seeds of solanaceous plants. Since the soil temperature is not constant diurnally, it was hypothesized that the duration of cold stress can have variable effects on vigor of Capsicum annuum L. It was observed that increasing the duration of cold stress (18 degrees C) up to 2 hours/day can improve the vigor but after 6 hours/day, a significant drop in vigor was observed. This was because of the cold-associated membrane damage leading to the leakage of electrolytes. To date, this stress existing in these regions has gone unnoticed. In this regard, biopriming the seeds with exopolysaccharide (EPS)-producing microbes can be useful as the EPS can form a protective layer on the seeds. Two lesser-known bacteria namely, Phytobacter and Priestia sp. were evaluated for their vigor-recovering ability. Treatment of seed with these microbes reduced the electrolyte leakage which improved the vigor under sub-optimal stress. This was also validated by fluorescent microscopy. Both these strains displayed an enhanced EPS-producing ability at 18 degrees C which correlated with the reduced electrolyte leakage and enhanced stability of cell membrane. Such bacteria can help in promoting seed vigor under sub-optimal temperature stress. Bacterial inoculation prevents cold-induced membrane damage in seedlings.

This study examines the dynamic shear strength properties of expanded polystyrene lightweight soil (EPS LWS) samples through dynamic triaxial tests, focusing on the effects of EPS bead content, cement concentration, and confining pressure. The results indicate that increasing the cement content positively correlates with the dynamic strength of EPS LWS due to the formation of reticulate cement hydrates that bond soil particles. When the cement content is below 10%, EPS beads have minimal impact on dynamic shear strength. However, at cement contents of 15% or higher, increasing EPS bead content reduces dynamic strength because the low-strength EPS beads break under these conditions. Elastic deformation in EPS LWS remains stable, with elastic strain increasing as EPS particle content and confining pressure rise. This highlights the significant impact of these factors on elastic strain, which is crucial for achieving the desired density and strength in engineering applications. The nonlinear behavior under dynamic stress and strain, showing strain hardening at critical levels. Higher EPS content reduces the dynamic stress required for bearing capacity due to decreased stiffness. Additionally, the dynamic elastic modulus increases with cyclic loading frequency, while higher confining pressure enhances hoop stress effects, requiring more dynamic stress to achieve the same strain. This study provides insights into the dynamic shear strength properties of EPS LWS, emphasizing the critical roles of cement content, EPS bead content, and confining pressure in influencing its performance in engineering applications.

Expanded polystyrene (EPS) bead-lightweight soil composites are a new type of artificial geotechnical material with low density and high strength. We applied EPS bead-lightweight soil in this project, replacing partial cement with fly ash to reduce construction costs. EPS beads were used as a lightweight material and cement and fly ash as curing agents in the raw soil were used to make EPS lightweight soil mixed with fly ash. The EPS bead proportions were 0.5%, 1%, 1.5%, and 2%; the total curing agent contents were 10%, 15%, 20%, and 25%; and the proportions of fly ash replacing cement were 0%, 15%, 30%, 45%, and 60%, respectively. Unconfined compressive strength (UCS) and scanning electron microscopy (SEM) tests were conducted. The results showed that the EPS content, total curing agent content, and proportion of fly ash replacing cement had a significant impact on the UCS of the lightweight soil. This decreased with an increase in EPS content and decrease in total curing agent content and decreased with increased proportions of fly ash replacing cement. When the proportion of fly ash replacing cement was not too high, the strength of the lightweight soil decreased less, and its performance still met engineering needs. At the same time, the soil can also consume fly ash and reduce environmental pollution. EPS lightweight soil mixed with fly ash still has advantages, and it is recommended to keep the proportion of fly ash replacing cement less than 30%. The failure patterns for lightweight soil mainly include splitting failure, oblique shear failure, and bulging failure, which are related to the material mix ratio.