Assessing the subsurface geological conditions beneath a structure is crucial, as soils inherently tend to lose intergranular strength when subjected to static or dynamic loads. Applying dynamic loads can result in the propagation of stress waves through the soil, leading to deformation of the soil structure and causing more significant damage than static loads. Extensive research has been conducted on treating dynamic characteristics of clay soil properties using traditional additives such as lime and cement. To achieve better results and address the limitations of conventional materials in soil improvement, there is a growing trend towards using nontraditional stabilizers, referred to as 'recycled and sustainable' materials. These include, for example, silica fume, polypropylene fibers, steel slag, fly ash, rubber tire particles, basalt, and recycled and crushed glass, which are currently being deeply investigated to improve the dynamic behavior of clay soils. The review article compares the effects of traditional and sustainable stabilizers on dynamic engineering properties of soils. It also highlights the engineering significance and innovations in the use of such materials. While traditional stabilizers effectively improve soil strength and durability, they pose environmental challenges, including increased CO2 emissions and brittleness under seismic stress. Innovations focus on refining these techniques and incorporating sustainable alternatives, such as waste-derived materials, to enhance soil properties, improve seismic performance, and reduce environmental impact. The study underscores the need for developing cost-effective, ecofriendly solutions for modern infrastructure. It systematically analyzes recent topics on soil stabilization using these additives, examining parameters that influence the dynamic properties of stabilized clay soils. Furthermore, it reviews microstructural changes due to stabilization and their impact on dynamic properties, offering suggestions for future research.

A profound understanding of the interaction between loess slopes and tunnels, along with the mastery of protective measures for tunnels crossing loess slopes, is crucial for ensuring the excavation and operation safety of tunnels in loess slope areas. This article summarizes research findings on the loess slope-tunnel system, concentrating on sources triggering failures, the acting mechanism of failures, and strategies for failure mitigation. Loess slopes, serving as the tunnel's bearing medium, may suffer from engineering disturbances during construction and operation, significantly affecting their stability. This is reflected in the intensification of crack formation, water infiltration, and vibration propagation in the slope. The degree of slope-tunnel interaction depends on relative spatial positioning, slope characteristics, and construction parameters. Although extensive research has focused on tunnel deformation in orthogonal systems, oblique systems require additional investigation. At different stages, preventing failure involves three levels: proactive avoidance, proactive mitigation, and passive reinforcement. Traditional approaches involve divide and conquer, but considering tunnels and slopes as an integrated whole is an emerging research area. Innovative technologies, like Negative Poisson's ratio anchor cables and Steel-Concrete Composite Support for challenging loess terrains, are introduced. Applying these technologies in practical engineering is recommended to accumulate experience and support their mature application. This review can offer valuable support for designing, operating, and managing tunnels crossing areas prone to loess landslides.