## 3 Experimental Results and Discussion  
### Effect of the Loading Rate on the Conversion Coefficient  
The axial stress-strain curves of soil under different loading rates are shown in the figure below. As observed in Figure 8, the samples all show obvious strain-softening characteristics in the uniaxial compression test, and axial stress decreases continuously after reaching the peak. The peak strength of the sample varies within the range of 90 kPa to 60 kPa, and the corresponding strain (hereinafter referred to as the peak strain) is between 0.02 and 0.06 when the stress reaches its peak. As observed in Figure 8, with the change in loading speed, the peak strain, elastic modulus, and peak strength of the stress-strain curve have certain changes. With the increase in strain rate, the peak strength also shows an increasing trend. However, the relationship between the peak strength and strain rate is nonlinear. When the strain rate is less than 2 \(\times\)\(10^{-4}\), the peak strength exhibits little change with respect to the strain rate. However, when the strain rate is greater than 2 \(\times\)\(10^{-4}\), the peak strength increases obviously with an increase in strain rate. This phenomenon is similar to the test results obtained by [PERSON] et al. (2018) in rock samples. It can be considered that the peak strength of soil also increases with an increase in strain rate. When the loading rate is within a low range, the compressive stress of soil samples is equivalent to static stress, and an increase in the loading rate has no obvious influence on the mechanical properties of soil. In this range, static loading tests are carried out on the samples. When the loading rate exceeds the range of the static loading test, the compressive stress on the soil mass can no longer be regarded as static stress. The influence of the loading rate on the mechanical properties of the sample begins to show. At this time, the peak strength of the soil mass gradually increases with an increase in the loading rate. The average peak strain of the sample when it reaches the peak stress is tested and the change in the average elastic modulus in the pre-peak elastic stage along with the strain rate is calculated, as shown in Tables 2 and 3. Its variation law is shown in Figure 9. It can be observed in the figure that similarly to the variation law of peak stress, the peak strain, elastic modulus, and other parameters have little change with respect to the static loading interval (the interval with a strain rate of less than 2 \(\times\)\(10^{-4}\)). After exceeding this interval, these parameters begin to change significantly with an increase in strain rate. The peak strain decreases with an increase in strain rate, and the elastic modulus increases with an increase in strain rate. Figure 8: Stress–strain curves of soil under different strain rates. The variation characteristics of soil samples are different with respect to different loading rate intervals. The mechanical properties of soil samples change little with respect to the loading rate during static loading intervals. In the dynamic loading interval, with an increase in loading rate, the peak stress and elastic modulus also increase, and the peak strain decreases. In the axial stress-strain curve, the peak is forward-facing, the pre-peak stress section becomes steeper, and the peak value increases. As observed in Figure 10, with a constant increase in strain rate, the stress conversion coefficient decreases gradually. When the strain rate is less than \(4\times 10^{-5}\), the failure mode comprises tensile failure, and when the strain rate is greater than \(6\times 10^{-4}\), the failure mode comprises shear failure.