Аннотация
The design and construction of the tunnel surface requires considerable time and cost. Therefore, improved methods of constructing the surfaces of underground structures is an urgent task in the mine industry. Everyone knows that the surface of the tunnel is a complex curvilinear surface, which must meet the pre-determined requirements. The article presents a new way of constructing the tunnel surface according to predefined conditions using the biquadratic transformation of the plane, which allows one to describe the design of each tunnel section by a single equation.