Open AccessNumerical Ultimate Load Analysis Based Study on Safety Monitoring Reference Value for Tunnels in Weak Rock
Author(s) -
Hongyan Guo,
Zhiwei Xiao,
Ké Li,
Hengxiang Song
Publication year - 2020
Publication title -
iop conference series. materials science and engineering
Language(s) - English
Resource type - Journals
eISSN - 1757-899X
pISSN - 1757-8981
DOI - 10.1088/1757-899x/741/1/012064
Subject(s) - rock mass classification , strength reduction , displacement (psychology) , geotechnical engineering , structural engineering , quantum tunnelling , reduction (mathematics) , safety factor , deformation (meteorology) , stability (learning theory) , ultimate load , geology , numerical analysis , ultimate tensile strength , engineering , computer science , mathematics , materials science , finite element method , geometry , psychology , mathematical analysis , oceanography , optoelectronics , machine learning , metallurgy , psychotherapist
It is usually hard to ensure overall stability and construction safety when tunneling in weak rock. Therefore, it is of practical engineering significance to conduct safety monitoring reference value study based on numerical ultimate load analysis by building an equivalent rock model. In this paper we investigate ultimate strains of equivalent rock masses of different classes based on numerical ultimate load analysis by building an equivalent surrounding rock model; examined the deformation reduction factor changes for different classes of surrounding rock by building a plane model for calculation and analysis; established tunnel stability assessment criteria through observation of ultimate shear strain diagrams under different reduction factors; and determined appropriate management measures according to warning levels. Our analyses show (1) under different loads the higher the rock mass classification the smaller its vertical displacement and hence its ultimate strain; (2) the higher the rock mass classification the more susceptible it is to strength, creep and instabilities; (3) Assessment criteria are established by comparing displacement U measured during tunneling with the ultimate displacement U0, i.e. the tunnel is stable if U U0.