## 2 Materials and Method
### Experimental Method and Process
#### 2.2.2 Experimental Parameters and Measurement Methods  
The evolution law for the temperature field, thermophysical properties, and mechanical properties with age after pouring of inner shaft lining concrete was the research object of this experiment. In the experiment, the temperature field of the shaft lining concrete in various positions was measured with copper-constant thermocouple wires and the temperature data recording terminal (Figure 3a). In order to investigate the evolution law for the thermophysical and mechanical properties of the inner shaft lining concrete with age, the test block mold was placed inside the shaft lining before the pouring process and then taken out when it reached a specific age for parameter measurement (Figure 3b). In the thermophysical and mechanical experiment, the test process and data processing follow the _Standard for Test Methods of Concrete Physical and Mechanical Properties_ (GB/TS0081-2019). Except for the elastic modulus, which is tested with 6 test blocks (100 mm \(\times\) 100 mm \(\times\) 300 mm), other parameters are tested with three test blocks (100 mm \(\times\) 100 mm \(\times\) 100 mm) and take the average value to characterize the thermophysical and mechanical properties of shaft lining at the predetermined age. The thermal conductivity and specific heat capacity of the shaft lining were measured using the thermal constant analyzer Hot Disk 500-V6 by adopting the transient plane heat source method. The measurement of the compressive strength \(f_{\text{cs}}\), tensile strength \(f_{\text{ts}}\), and elastic modulus \(E_{\text{c}}\) of the test block was completed with the 200 t \begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Concrete** & **Cement** & **Sand (kg)** & **Sand Ratio** & **Water Reducing** & **Water Cement** \\
**Grade** & **(kg)** & **(\%)** & **(\%)** & **Agent (\%)** & **Ratio(-)** \\ \hline C60 & 460 & 800 & 38 & 0.60 & 0.34 \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Comprehensive mix of concrete used in the experiment. Figure 3: Measurement of various parameters: (**a**) testing equipment for concrete temperature, (**b**) demolding of the test block, (**c**) testing equipment for the thermophysical properties of the material, (**d**) compressive strength testing, (**e**) tensile strength testing, and (**f**) elastic modulus testing. versity of Mining and Technology (Figure 3d,f). During the tests of compressive strength and tensile strength, the loading rate of the test block (100 mm \(\times\) 100 mm \(\times\) 100 mm) is kept at 0.5 mm/min, and the ultimate load F is obtained according to the loading curve. According to the _Standard for Test Methods of Concrete Physical and Mechanical Properties_ (GB/T50081-2019), the compressive strength and tensile strength were calculated based on the ultimate load F in accordance with Equations (1) and (2), respectively. The elastic modulus \(E_{c}\) was determined by unconfined compression testing, and six test blocks (100 mm \(\times\) 100 mm \(\times\) 300 mm) are used for this test, three of which are used to determine the axial compressive strength, and the other three are used to determine the compressive modulus of elasticity. The strain of the test block is measured by pasting the resistance strain gauge with a gauge length of 150 mm on the side of the test block (Figure 3f). According to the above test standard (GB/T50081-2019), the elastic modulus is calculated by using the ratio of the stress value in the elastic change stage to the strain value at the corresponding time point, as shown as Equations (1)-(3).