## 4 Conclusions  
This study analyzes the evolution of the thermophysical and mechanical properties of inner shaft lining concrete with age during the initial pouring period through a series of experiments. The influence of shaft lining thickness on the internal temperature field and \begin{table}
\begin{tabular}{c c c c c c} \hline \hline \multirow{2}{*}{**Number**} & **Elastic Modulus (10\({}^{4}\) MPa)** & **Time (d)** & **Thickness (m)** & **Fitting Equation** & **R-Squared** \\ \hline
1 & y & x & 1.0 & \(y=-0.0233x^{2}+0.2383x+2.9550\) & 1 \\ \hline
2 & y & x & 1.2 & \(y=-0.0254x^{2}+0.2567x+2.9788\) & 1 \\ \hline
3 & y & x & 1.5 & \(y=-0.0104x^{2}+0.1067x+3.3237\) & 1 \\ \hline \hline \end{tabular}
\end{table} 
Table 6: Evolution equation for elastic modulus with age within the first 7 d after pouring. Figure 10: Evolution of elastic modulus with age within the first 7 d after pouring. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline \multirow{2}{*}{**Number**} & **Tensile Strength (MPa)** & **Time (d)** & **Thickness (m)** & **Fitting Equation** & **R-Squared** \\ \hline
1 & y & x & 1.0 & \(y=-0.0279x^{2}+0.3717x+2.5163\) & 1 \\ \hline
2 & y & x & 1.2 & \(y=-0.0258x^{2}+0.3383x+2.7775\) & 1 \\ \hline
3 & y & x & 1.5 & \(y=-0.0462x^{2}+0.5150x+2.6213\) & 1 \\ \hline \hline \end{tabular}
\end{table} 
Table 5: Evolution equation for tensile strength with age within the first 7 d.  
the evolution of thermal conductivity, specific heat capacity, compressive strength, tensile strength, and elastic modulus are emphatically analyzed. From the experiment results and analyses, the following major conclusions can be drawn:  
1. The evolution of temperature in an inner shaft lining within the first 7 d after pouring can be divided into five stages: induction, slow heating, rapid heating, rapid cooling, and slow cooling. The maximum temperature of the inner shaft lining concrete gradually increases with the lining thickness and can reach 76.5 \({}^{\circ}\)C when the thickness is 1.5 m. The maximum temperature in the shaft lining is not always at the center in the radial direction but gradually moves outward with the increase of thickness. 2. The thermal conductivity of inner shaft lining concrete decreases significantly with an increase in age. Simultaneously, the thermal conductivity of the inner shaft lining concrete increases with the lining thickness. The thermal conductivity of the inner shaft lining concrete with thicknesses of 1.0, 1.2, and 1.5 m evolves between 0.92 and 2.16 W/(m\(\cdot\)k) within the first 7 d after pouring. 3. The specific heat capacity of shaft lining concrete decreases significantly with an increase in age, and the decline rate gradually decreases with an increase in age. The specific heat capacity of material at the same age increases significantly with an increase in thickness. The specific heat capacity of the inner shaft lining concrete at thicknesses of 1.0, 1.2, and 1.5 m evolves between 0.66 and 0.98 KJ/(kg\(\cdot\)k) within the first 7 d after pouring. 4. The compressive strength of the shaft lining concrete increased significantly with an increase in age within the first 7 d after pouring, and the increase rate gradually decreased with an increase in age. The compressive strength at the same age increases significantly with the thickness, and the increase rate has no apparent association with the thickness. The compressive strength of the inner shaft lining concrete with thicknesses of 1.0, 1.2, and 1.5 m evolves between 37.33 and 57.01 MPa within the first 7 d after pouring. 5. The tensile strength of shaft lining concrete significantly increases with age, and the increase rate gradually decreases with an increase in age. The tensile strength of the shaft lining concrete at the same age increases gradually with the thickness, but the increase rate has no apparent association with the thickness. The tensile strength of the inner shaft lining concrete with thicknesses of 1.0, 1.2, and 1.5 m evolves between 2.86 and 3.96 MPa within the first 7 d after pouring. 6.