Investigation On Damage Mechanism And Anti-explosion Performance Of Tunnel Lining Structures Under Internal Blast Loading

As the highway, railway and urban transport networks continue to improve in China, traffic tunnel increases rapidly in number. It is very crowded in urban underground tunnels and the space is closed, which provide the objective conditions for terrorist attacks. In highway tunnels, auto collisions, chemical explosions and other accidents frequently occur. All these are prone to result in the damage and collapse of tunnel lining structures, and vehicular traffic disruption as well as loss of lives and properties. It is therefore of great significance to study the dynamic response and damage mechanism of tunnel lining structures under internal blast loading for anti-explosion protection design.Based on extensive comparisons of the constitutive models suitable for simulation of concrete, rock and soil, systematic and intensive study on the damage mechanism and anti-explosion performance of tunnel lining structures under internal blast loading are carried out. The main work in this paper can be summarized into following several aspects:(1) The constitutive model of material is the foundation of numerical simulation. This paper summarizes various kinds of material models of concrete, rock and soil, and points out their advantages and disadvantages, in order to choose suitable material constitutive models for anti-explosion analysis.(2) It is difficult to obtain accurate explosion loading model during structural design. In order to investigate the anti-explosion performance of tunnel lining structures, numerical simulations taking into account fluid-solid coupling interaction are conducted for the analysis on the dynamic responses of tunnel lining structures under internal blast loading using AUTODYN software, especially focusing on its damage mechanism.(3) Influences of explosive charges, reinforcement ratios, geological conditions and embedded depths of tunnel on dynamic response and damage mechanism of lining structures are analyzed to assess the structural anti-explosion capability.(4) The anti-explosion performance of tunnel lining structures decorated with aluminum foam as protective layer are studied. Compared with the conditions without aluminum foam, different thicknesses of protective layers are analyzed to explore the anti-explosion mechanism of aluminum foam.