2.Design Models for Underground Structures 2.1 Introduction Different kinds of model theories have been established to simulate different surrounding grounds. Category Main ideas and applications Empirical model Depend on experiences from past practice in the familiar engineering conditions. Action from ground is reflected as loads Load structure on structures,while the resistance from the Layer should be considered. Ground structure Structures and ground are modeled as a system model and numerical method is often involved. Convergence and The characteristic curves of ground and support confinement model should be used and this method is effective in the design of underground opening in soft rocks 百年同濟11 TONGIUNIVERSΠTY11 2.1 Introduction Different kinds of model theories have been established to simulate different surrounding grounds. Category Empirical model Load structure Ground structure model Convergence and confinement model Main ideas and applications Depend on experiences from past practice in the familiar engineering conditions. Action from ground is reflected as loads on structures, while the resistance from the Layer should be considered. Structures and ground are modeled as a system and numerical method is often involved. The characteristic curves of ground and support should be used and this method is effective in the design of underground opening in soft rocks. 2. Design Models for Underground Structures