CALCULATION METHOD OF STRESS RELEASE RATIO USED FOR TUNNEL DESIGN AND ITS PROGRAM

摘要

PROBLEM TO BE SOLVED: To provide a method and its program capable of accurately calculating the stress release ratio, by analyzing excavation of taking into consideration rigidity of timbering.;SOLUTION: This calculation method of the stress release ratio used for tunnel design, comprises a process of making an analytical model, by dividing an excavation part, a timbering installing part and the surrounding natural ground into finite elements, by setting an elastic modulus of a boring advancing section, the surrounding natural ground and the timbering for excavating the predetermined length and installing the timbering, a process of successively repeating processing for calculating nodal point displacement and stress in the radial direction of the element positioned in a boundary between the natural ground and the timbering in the (i-1)-th boring advancing section, until (i) becomes the total number of the boring advancing sections by increasing the (i) 1 by 1, when the i-th excavation is completed, by excavating the i-th boring advancing section, after installing the timbering of the (i-1)-th boring advancing section, a process of calculating an average value in the respective boring advancing sections of the nodal point displacement and the stress in the radial direction of the element positioned in the boundary between the natural ground and the timbering, and a process of determining the stress release ratio on the basis of an average value of the nodal point displacement in the boring advancing section and an average value of the stress in the radial direction in the boring advancing section.;COPYRIGHT: (C)2008,JPO&INPIT