## 1 Introduction  
The concept and principle of soil reinforcement were first developed by [PERSON] in 1969 when he found that adding reinforcements to a soil mass increases the shear strength of soil [1]. The reinforcing effect of fibers in soil reinforcement was first noticed by [PERSON] in 1977, when he observed that natural root fibers contribute to the improvement in soil strength due to their reinforcing effect [2]. In general, in fiber-reinforced soils, it has been observed that the added fiber can improve the mechanical properties of the soil due to the interface friction between the fiber and the soil. That is, the shear stresses in the soil actuate the tensile strength in the fibers and, as a result, give the soil more strength [3; 4; 5]. Randomly Distributed Fiber-reinforced Soil (RDFS) is a soil improvement technique in which fibers of desired properties and quantities are randomly ordered and compacted in place [6]. The RDFS method has become more popular in recent studies. Short staple fibers can be easily added and mixed into the soil such as cement, lime, or other additives. In this way, planes of weakness do not occur in the soil and an isotropic increase in the strength of the soil composite can be achieved [7; 8]. Glass fiber improves the mechanical properties of the reinforced soil matrix such as flexural and tensile strength. They contribute to the flexibility of the soil matrix they are supplemented with and have a long period of use [9; 10]. Glass fiber-reinforced sandy soil matrices have attracted great interest in many applications because of their relatively low weight, low cost, and good mechanical properties, which are desirable characteristics of natural fibers [11; 12]. [PERSON] et al. [13], in this study, first stabilized the soil with Class F fly ash and cement to improve the strength properties of the weak local soil and then reinforced it with glass fiber reinforcement. In the study, different mixtures were prepared with varying ratios such as fly ash (10, 30, 50), cement (0.5%, 1, 1.5, 2%), and glass fiber (0.25%, 0.5 and 1%). It was observed that there was a significant improvement in the pressure and shear strength parameters in the optimum additive percentage determined for all three materials. [PERSON] et al. [14] conducted direct shear box tests for their study to examine the effect of material properties and fiber content on the shear resistance of sand. In the study, glass fiber, polypropylene fiber, and sisal fiber were randomly reinforced into the soil mass at 50% relative density, 0.25%, 0.5, 0.75, and 1 ratio. It was observed that samples reinforced with sisal fibers had a more significant increase in strength parameters than samples reinforced with glass or polypropylene fibers. The reason one of the fiber types used in the experimental study was chosen as glass fiber is that it was thought to be suitable for comparing the results with basalt and macromesh fibers, as it is a familiar material that has been studied in the past. Basalt fiber has high performance, natural compatibility, electrical insulation, corrosion, high temperature, and acid and alkali resistance [15; 16]. When the studies in the literature are examined, it has been seen that it is widely used in thermoset resin and concrete as insulation, sound absorption, heat resistant materials, and reinforced materials [17; 18]. In addition, the mechanical properties of basalt fiber such as tensile strength and modulus of elasticity, are much higher than polypropylene fiber [19; 20]. Many studies have been carried out on concretes in which basalt fiber is used as an admixture. However, the use of basalt fiber additives in soil-related studies is relatively low [21]. [PERSON] et al. [16] used three different lengths of fiber (12 mm, 18 mm, and 24 mm) to investigate the effect of basalt fiber additive on improving soil properties. They added 12 mm and 18 mm long fibers to the ground at a rate of 1.5%, 3%, 4.5%, 6%, and 24 mm long fibers at a rate of 1.5%, 2%, 2.5%, and 3% by weight. [PERSON] et al.