The Lesotho Highlands Water Supply Project is the largest bilateral infrastructure project between Lesotho and South Africa. It is carried out in four phases. The project plans to lead the rich water resources of Lesotho's mountainous areas to South Africa through the construction of complex tunnels and dam hubs. Among them, the Polyhari Water Transmission Tunnel is the main project of the second phase of the Lesotho Highlands Water Supply Project. It is led by the 11th Bureau of Power Construction and Hydropower of China, and is jointly implemented with the 3rd Bureau of Hydropower and the South African localized enterprise Unique. The project is located in Lesotho. It is located in the southern interior of Africa. Due to the fact that the altitude of the country exceeds 1000 meters, the snow is heavy in winter and the ultraviolet rays are strong. It has strict requirements for houses. Combined with the actual situation of the customer, the solution of combining villas, ZA houses and H steel is finally adopted. It meets the needs of the customer and saves the cost to the greatest extent