# A Review of Road Design for Wind Farms in China
## 4 Research on Profile Design
\begin{array}{l l l l}R_{\mathrm{min}}=\frac{V^{2}}{4\Gamma}\\ L_{\mathrm{min}}=\frac{V}{\Gamma\Sigma}\\ D=3-(29.8-\frac{L}{2})w,L\leq 29.8\mathrm{m}\\ D=3-\frac{29.8^{2}}{2K},L\text{\textgreater{}}29.8\mathrm{m}\end{array} \right. \tag{18}\] \begin{table}
\begin{tabular}{c c c c} \hline \hline \multirow{2}{*}{**Design Speed/(km/h)**} & \multicolumn{2}{c}{**Minimum Radius of Concave Curve**} & \multicolumn{2}{c}{**Minimum Radius of**} & \multicolumn{2}{c}{**Minimum Length of**} \\ \cline{2-4}  & **Recommended Value** & **Slope Difference/\%** & **Convex Curve/m** & **vertical Curve/m** \\ \hline
5 & 200 & 4 \(\leq\) w \(\leq\) 10 & 100 & 10 \\
10 & 200 & 6 \(\leq\) w \(\leq\) 10 & 100 & 12 \\
15 & 200 & 8 \(\leq\) w \(\leq\) 10 & 100 & 16 \\
20 & 250 & 8 \(\leq\) w \(\leq\) 30 & 150 & 20 \\
25 & 250 & 10 \(\leq\) w \(\leq\) 30 & 200 & 25 \\
30 & 300 & 10 \(\leq\) w \(\leq\) 30 & 250 & 30 \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Recommended minimum radius and length of the vertical curve of the fan transport road ([PERSON] et al., 2018). \[\left\{ \begin{array}{l}R_{\min}=\frac{V^{2}}{4\Gamma}\\ L_{\min}=\frac{V}{\Gamma 2}\end{array} \right. \tag{19}\]  
In the above formula:  
\(R_{\min}\)--Minimum vertical curve radius;  
\(L_{\min}\)--Minimum vertical curve length;  
\(D\)--The distance from the blade tail to the ground shall be calculated separately when the vertical curve length is less than or equal to or greater than the blade tail length. The safety judgment condition shall be that the distance does not exceed 1 m;  
\(R\)--Vertical curve radius. When the semi-trailer is running on a concave curve, the minimum curve radius corresponding to the safe front depression angle of the semi-trailer during operation is 98.22 m, and the minimum curve radius corresponding to the safe front depression angle during running on a convex curve is 85.94 m;  
\(L\)--Length of the vertical curve;  
\(V\)--Vehicle speed (km/h);  
\(w\)--Slope difference between the two adjacent straight slope sections. [PERSON] [32] and others took Taohuashan Wind Farm as an example to fully analyze the wheelbase and chassis ground clearance of transport vehicles in the wind farm for the transportation of major equipment in the wind farm. According to the main size parameters, the minimum radius of the convex curve and concave curve of the road surface that meet the requirements of transportation of major equipment in the wind farm shall be determined by drawing and shall not be less than 135 m and 210 m, respectively. When modifying the vertical curve of pavement, select the larger value in combination with the minimum radius of the corresponding specifications of highway engineering as the minimum radius of the vertical curve of pavement of the project. According to the characteristics of wind power projects in mountainous areas, [PERSON] [33] proposed to make full use of the natural terrain in the design of the vertical section, and at the same time, consider the needs of large cargo transportation and control the maximum limit vertical slope not to exceed the limit climbing capacity of transportation vehicles. The radius of the vertical curve of the road is generally not less than 300 m on the premise of avoiding the floor from touching the ground. At the same time, in order to save investment, the quantities of road excavation and filling shall be reduced to the most reasonable range as far as possible during the profile design. [PERSON] [24] and others, taking the actual project as the background, made a comprehensive analysis of the vertical section in view of the problems encountered in the vehicle transportation of mountain wind farms, comprehensively considered the vehicle performance and traffic conditions, proposed the calculation method of the maximum gradient that the vehicle can climb when driving at a constant speed.