Based on the characteristics in the strength of coal seam under the action of the ground pressure, the impact coal cutting is achieved in the coal winning technique by using the impact cutting tool to impact, split and cut the coal on the coal wall.

To the cracks on the bottom of the slabs,the effect of water is just like the uniform forces assigned on the crack face which lead to the cracks to split.

Plain high strength concr ete and plain normal strength concrete,fiber high strength concrete and fiber no rmal strength concrete were tested respectively with split test and their capaci ty to resist propagation of.

Several suggestionsto improve the method of testing cleavage strength were presented.

Based on stress analysis of soil mass in the course of cleavage grouting,the cleavage type of different kinds of soil mass is discussed in this paper.

Dependence of polar Kerr effect on electron spin exchange splitting;

The results indicate that the conductance and the resonant splitting are dependent on the structural dimension, the number of quantum dots and the strength of negative potential.

On the basis of the theory,the paper analyzes the effects,such as permeability,compaction and splitting,of post-grouting to pile shaft and soil around pile tip qualitatively,and the paper also analyzes the change of front-to-back bearing capacity and its influencing factors.