Primary parametric resonance of thin rectangular plate on nonlinear elastic foundation;

Adopting Galerkin s method,the nonlinear dynamical equations,with double modals and under double parametrically excitations,is established to investigate a thin rectangular plate on the nonlinear elastic foundation with small deformation.

A nonlinear dynamical equation of the small deformation thin rectangular plates on nonlinear elastic foundation subjected to harmonic excitation is established.

Stability of relativistic rotational nonlinear dynamic equation and solution for a kind of nonlinear elastic coefficients;

An elastic subgrade reaction method considering nonlinear interaction between protection-structure and soil for deep excavations;

In excavation engineering,the horizontal coefficient of subgrade reaction is irrelevant to horizontal displacement of retaining structures in the elastic subgrade reaction method.

The new calculation method introduces the conception of stiffness matrix of foundation elastic reaction and has better theoretical accuracy compared with the traditional algorithm.

On the basis of computed results of slide-resistant piles with the method of coefficient of subgrade reaction, some curves of transmission coefficient of slide-resistant piles under loads are given.