FIGURE 3 Sample preparation and size (a) Interfacial sample,
(b) Constant temperature process
2.4 Testing Device
Due to the strong water-heat sensitivity of frozen soil, a constant
normal stiffness direct shear apparatus (Figure 4) was used to conduct
interfacial characteristics research in order to better control the
experimental temperature. The direct shear apparatus was first installed
in a thermostat with a temperature control accuracy of ±0.2℃, and then
the thermostat was placed in a freezer with a temperature control
accuracy of ±0.5℃. This two-level temperature control system achieved
good temperature control accuracy.