The calculating results indicate that frontl support part has to be pressed terminally and circular angle of blasting cut - out is larger than substraction of half circular angle of terminally pressed area from π.

The choice of blasting notch configuration,the determination of blasting parameters and the taken technical measures of a 45-metre-high brick chimney by directional folded in complicated environment are introduced,it is hoped that this paper can accumulate some experiences for the similar engineerings.

From analyzing the mechanics of axis rotation of chimney after being blasted, and rupture form of blasting notch.

Directional controlled blasting was used to demolish a 45-meter-high brick-structured chimney, and the position of the blasting cut was properly heightened according to the structure of the chimney and the complicated environment.

This paper focused on the defined method of the blasting cut,the selection of rational blasting parameters,the execution of the trail-blasting solution and the pretreatment method,corresponding safety precautions and the controlling method of blasting and touching vibration.

The form of blasting cut is experimentally studied.

For polymethyl methacrylate(PMMA),dynamic fracture tests were conducted by using central notched circular disk specimen in the split Hopkinson pressure bar.

For polymethyl methacrylate(PMMA),pure mode I fracture tests were performed under quasi-static loading by using central notched circular disk specimen.