It is put forward that the top coal of low gaseous steep seam can be caved only when the top coal is in the limiting equilibrium state of stress under the abutment pressure.

Theoretical analysis and experimental study on pile-soil ratio under limit state of bearing capacity;

《Criterion of Concrete Gravity Dam Design》(DL 5108-1999) makes great and important recensions in structure design: as the probability limit condition design principle,uses partial factor limit condition design expression instead of setting calculation principle and method in the old criterion.

Probability analysis of the curvature limit state and ductility of circular RC bridge piers;

Crack controlled analysis on the limit state of reinforced concrete beams;

Computation of earth pressure on large diameter cylinder under service ultimate state;

Based on the field testing data of 82 piles in 40 sites,through the study on the mobilization characteristics of pile total skin friction with pile head settlement,it is found that:(1) the total skin friction of 13 piles degrade in 36 piles whose total skin friction have arrived at ultimate state;(2) there are four types for pile total skin friction′s degradation,i.

On the basis of research achievement, a new design method on durability of concrete structure, which is used to check the durability ultimate state, is suggested in the article.