A segmented tangent modulus model was developed based on a great deal of triaxial compression test data and Duncan s nonlinear model of soil.

The origin of the residual stress inside welded steel structures,the theory of tangential modulus for nonelatieal column with caleulating and that of equivalent tangetial modulus with calculating residual stress are described.

In traditional tangent distance classification method,the seletion of tangent vectors depends on peoples participation.

Research on tangent modulus of gravel core materials under high pressure;

Presents the typical stress-stain relationship for description of softening behavior of soils, from which a mathematical expression for the description of such a relationship, an expression of secant modulus and tangent modulus, and a method of determining parameters in the expression are established, and a typical example to illustrate how to determine parameters from test data.

A modified Ducan-Chang model for calculation of tangent modulus Et,and a modified D Daniel equation for determination oftangent Poisson ratio μt,have been suggested.