It analyses the reasons which causes the common quality problems including pile cracks,pile-top breakage,substandard sinking-pile design requirements and splitting joint,and brings forward the protecting measures and solving plan,so as to ensure the constructing quality and the safety of top structure.

The repeated mining face layout,equipment selection and extraction technology with cataclastic roof had been designed.

In connection with common accidents in constructive pr ocess of steel bar & concrete prefabricated pile,it analyzes cause of its accide nts from aspects of split on top of the pile?broken body of the pile?slippery or translocation of the pile & gush of the pile and puts forward concrete handli ng methods & preventive measures so as to be references.

The anchoring theory, technology and its application effect on thin-bedded and cataclastic roof are important topics to be studied The geomechanics condition, surrounding rock characteristics and construction method of the starting cut with large section in a fully mechanized mining are introduced.