# Compression Behavior of Rubber-Bentonite Mixture under Different Salinities
## 1 Introduction  
Bentonite is widely recognized in industry worldwide as one of the most suitable materials for buffer barrier systems in high-level radioactive waste disposal facilities owing to its exceptional swelling and impermeability properties [1, 2]. However, the subsurface water at nuclear waste disposal sites is often salty in terms of temperature and chemical composition. As groundwater permeates through the ground, it can lead to changes in the permeability, compressibility, and strength of bentonite. This poses a risk of the direct erosion of the external structure of nuclear waste storage tanks by groundwater, potentially resulting in the outward migration of high-level radioactive nuclides. This can have a severe impact on the surrounding environment and ecosystem. Rubber materials have emerged as crucial elements in the field of vibration reduction and sound insulation due to their favorable damping properties. These properties enable them to effectively absorb and disperse vibration energy within vibration isolators [3, 4]. The application of rubber materials in the domain of vibration isolation offers remarkable comfort and protection. These materials exhibit high durability and stability, making them capable of withstanding varying pressures, weights, and environmental conditions [5, 6, 7]. Additionally, rubber materials possess resistance against corrosive substances like acids, alkalis, and chemical solutions. Given their exceptional properties, rubber materials findextensive usage in many projects such as construction, bridges, roads, railways, airports, and ports, as well as aerospace, military, medical, and other fields [8; 9]. Rubber isolation pads represent a commonly employed form of rubber material for vibration reduction and isolation applications [10; 11]. These pads consist of a layer of rubber and are placed between two vibration isolation structures to deliver optimal isolation performance. When subjected to vibration transmission, the rubber material absorbs energy and uniformly distributes the load to the surrounding environment. Another method of vibration isolation that relies on rubber materials is the employment of rubber shock absorber rods [12]. These rods, composed of one or more rubber pipes, find use in mechanical, construction, bridge, road, and similar applications and can withstand compression and shear forces while effectively reducing structural vibration. Consequently, they are highly suitable for managing substantial vibration levels. Rubber isolation bearings also represent an application in which rubber materials are commonly employed for vibration reduction and isolation. Consisting of one or more layers of rubber pads, these bearings find placement in building structures, bridges, roads, and other relevant areas. They can support, disperse, and absorb the weight of structures, thereby reducing the impact of vibration and noise. Furthermore, rubber isolation bearings exhibit exceptional durability and stability, enabling them to withstand heavy loads. With their advantageous damping properties, they effectively minimize vibration transmission between a structure and its foundation. As a result, they find widespread use in buildings, roads, bridges, and various other infrastructure [13; 14; 15]. Research on the compaction characteristics of bentonite clay minerals began with the study of its mud state [16]. Researchers introduced water to bentonite to exceed its natural liquid limit [17] and investigated the changes in the porosity ratio under graded loading at a high water content to determine the optimal compaction performance. In practical engineering, compacted bentonite is commonly employed as an external buffer material for high-level radioactive waste storage tanks. By comparing the compression curves of compacted and mud-state bentonite [18; 19; 20], it is observed that in the compacted state, montmorillonite particles exhibit partial expansion of the diffuse double layer due to the smaller initial porosity [21].