STUDY ON THE STABILITY OF SHIELD WORKING FACE BASED ON LIMIT EQUILIBRIUM THEORY

摘要

The cutter pressure of shield construction on excavation face is the key factor to ensure stability of excavation face in the process of earth pressure-balanced shield construction. It is helpful to ensure the shield construction safety and impact reduction on surrounding environment. Based on the limit equilibrium method, the limit equations of earth pressure is established when the working face is actively damaged and passively damaged in the shield construction. Earth pressure is formulated by means of Lagrange multiplier, and functional extremum problems of active and passive earth pressure are changed into general function extremum problems by taking into account of the boundary conditions of the problem to be solved. The calculation formula and the location of active and passive earth pressure are deduced, and the formula is verified by the results of site monitoring and statistics further more.