2 EXPERIMENTAL MATERIALS AND METHODS

2.1 Soil

The soil used in the experiment was taken from a slope in Lanzhou City, Gansu Province. It appears as a light-yellow color, with uniform and continuous texture, and without large particulate impurities. The basic physical properties of the soil are shown in Table 1. The soil particle size distribution curve is presented in Figure 1. According to the soil classification standards (ASTM D2487/Standard for Soil Test Method GB/T50123-2019), it is classified as silty clay.。TABLE 1 Basic physical properties of silty clay