Overbreak excavation instability and local instability are indicated on the phase of construction about soil nail wall on the base of different instability situation about two cases,when excavation beginning.

The results suggest that 20% of moment redistribution at the internal support could be gained in the local buckling design of continuous composite beams with the non compact cross section(class 3).

The analytical results show that failure of members with low slenderness ratio tends to cause local buckling,while failure of members with high slenderness ratio will cause flexural buckling.

The results show that the failure mode of extended endplate connection is the large deformation of bending taking place initially in the tensile zone of endplate and column flange,and then the local buckling of compressive zone in connection causes the loss of carrying load.

The influence of deformation force and all kinds of technology parameters about cross rolling of hollow parts effect on oblate stability of cross rolling of hollow parts are analysed so that the standard of oblate stable is defined about cross rolling of hollow parts.

Analysis of the probability of voltage instability based on Thevenin equivalent parameters;

Mid and longer-term voltage instability are usually caused by the continuing increase of the load, and is characterized by a period when the voltage drop down quite slowly.

In order to make up the deficiency of traditional analytical method used in the research of voltage stability problem, we need to know the probability information concerned with voltage instability.

The numerical compression instability induced by the traditional kernel functions was discussed.

It removes numerical compression instability which appears in corrective smoothed partic.