Based on the bad stability property in the soft rock of two-way mountain tunnel in loess area and by means of the three-dimensional finite element method,the effect of the length of step and the length and the width of core soil on the longitudinal displacement of tunnel face,the plastic zone depth behind tunnel face and tunnel plastic area are analyzed.

This paper probes into the ringlike drift heading method for multidrop tunnels with preformed core soil, introduces the construction flow sheet, the construction methods and construction control key points, and puts forward some measures for the quality and safety of the construction.

The research of the core concrete s empty which influences the mechanics performance of concrete filled steel tube components is a hot issue currently.

It is an important approach for improving carrying capacity of steel tube-confined concrete to improve strength of core concrete.

To develop the design and computational theory for FRP reinforced concrete structure and provide theoretical basis for its application, considering three typical service stages, axial stress expressions of GFRP tubes and concrete core were derived based on classical laminate theory and equilibrium of forces.

Expansion rule of concrete core in self stress lightweight concrete filled steel tube,relationship between self stress and steel content ratio,and super performance of self stress lightweight concrete filled steel tube are gained through comparison test;damage process of short columns under axial load is analyzed.