Abstract: The active articulated shield machine is widely used in curved tunnel excavation. The precise calculation of its shield posture is the core function of the automatic guidance system of the shield machine, and it is also the premise and foundation for the real-time deviation correction of the shield machine in shield construction. The current situation of shield machine automatic guidance system providers at home and abroad keeping their own shield machine positioning calculation principles and methods secret has brought great difficulties to shield machine positioning manual review and shield construction. Based on the study of two domestic shield machines and the prism method automatic guidance system of the Japanese calculus workshop, a precise positioning calculation method for the active articulated shield machine is proposed by using the principles of solid geometry and spatial projection transformation, and the detailed calculation formula is given. Through the calculation and comparison of multiple sets of positioning coordinate data of multiple shield machines in different tunnel lines, the correctness of the precise calculation method of shield posture is verified.

Key words: automatic guidance system, shield posture, hinge angle, spatial analytic geometry, 3D transformation