Seismic analysis of shallow tunnel collapse mechanisms with the horizontal slice method

الملخص EN

The paper presents an analytical method to evaluate tunnel collapse mechanisms during earthquakes; seismic solutions are established based on the horizontal slice method and the variational principle.

Different sliding surfaces are applied to be compared with each other, and the finite difference method is employed to verify the analytical results.

Then, the conclusions come out that it is conservative to leave out the vertical force and regard the static earth pressure as the horizontal stress at the vault section.

Curved sliding surfaces are more reasonable than the linear sliding surface.

The tunnel safety factors on a sliding surface change between 0.89 and 2.44 during earthquakes with 0.3g.

When the number of undetermined constants is 2 and the different locations of the start damage point are taken into account, the curved sliding surface is reasonable to analyze the shallow tunnel collapse mechanisms, and the analytical results have excellent agreement with the numerical simulation and previous studies.

By parameter analysis, it shows that the tunnel depth & radius, friction angle, and cohesion of soil have an obvious influence on the sliding surface distribution.

Tunnel radius and cohesion of surrounding soil are the two most important factors influencing the tunnel stability.

Reducing the tunnel radius and increasing cohesion are the most useful ways to enhance shallow tunnel stability during earthquakes.