Experimental Research on Dynamic Characteristics of Porous Basalt in Freezing-Thawing Conditions

In subgrade slope engineering, latticed skeleton slope protection is the most common, but the temperature difference between day and night is large in northern China, resulting in the weakening of slope supporting capacity. In order to study the impact compression test of the basalt after freezing and thawing of the slope rock, the number of freeze-thaw cycles, different curing states and different dynamic impact velocities were selected as typical working conditions to analyze and discuss the influence of the mechanical properties of Hopkinson basalt on the freeze-thaw cycle, and to ensure that the slope in the cold region has good compressive performance under impact loading, the influence of 50 mm diameter separated Hopkinson pressure rod on the dynamic strength of the freeze-thaw cycles was analyzed. The experimental results showed that with the increase of impact velocity, the dynamic compressive strength of each rock sample showed a linear growth trend. Under the same strain rate and the same number of freeze-thaw cycles, the freezing curing environment had an enhanced effect on the bearing capacity of rock samples, and the saturated conservation environment had a softening effect on the bearing capacity of rock samples, and the peak strength of dynamic compressive resistance in freezing environment was the largest, and the strength of saturated state was the smallest, and the two intensity factors gradually approached 1 with the increase of freeze-thaw cycles. The change of strain rate of the dynamic strength of rock samples was most significant in the early stage due to the weakening effect of freeze-thaw cycles. With the increase number of freeze-thaw cycles, the strain of saturated specimens gradually increased, and the peak stress gradually decreased. In the late stage of freezing and thawing, the strength change and strain rate effect of rock samples were gradually weakening.