| The blast demolition of structure is a new technology, which sprang up in the 1970s. Unlike the traditional demolition techniques, it has been the first choice of demolishing projects because of its great competitiveness due to safety, high efficiency, low cost and doing without complicated equipment. In the past decades, much practice of blasting demolition and some academic studies has been carried out so that lots of experience has been accumulated and many experiential formulas have been achieved. However, thanks to the complexity of extreme energetic intensity, transient behavior, high speed and structural breaking mechanism and collapse mode in the blast, it is of great difficulty from both theoretical and testing perspectives. Its involving various scientific spheres leads to the lag of blasting theories comparing with engineering practice. Thus, a condition appears: on the one hand, demolition blast has been widely used in the field of demolition with its distinctive superiority; On the other hand, we are facing all kinds new structure types, tall buildings and adverse blasting circumstances. Frequently accidents have been generated by lack of theoretical guide and analogical experience, causing unnecessary loss.The paper carries out a systematic deep-going theoretic study, experimenting study and engineering application study. Structural demolition and blasting seismic effect have been dealt with and a calculating program has been made for predicting blast vibration. In the following are the main achievements: (1) Summing up the blast theories of solid media, the paper probe into the modes and blast parameter of blast demolition of buildings and factory structures. A corresponding model of collapse mechanics has been built and collapse conditions and movement laws of collapse have been reaped after the systematic study of the collapse process during the directional blasting of masonry barrel structure and reinforced concrete barrel structure. It has great theoretical and practical value for structural demolition. Furthermore, it can be directly applied in designing.(2) Applying the theory put forward in the paper to the directional demolition design of huge, low, and major diameter water tower made of reinforced concrete, employing shapes of blasting notches different from the normal ones[ 2, 99] and breaking the usual limit that the notch is as 1~2 time high as the wall thickness contribute to good demolition effects.(3) The functioning principle of shock wave in water-infusion blast has been brought to light by using structural dynamic mechanic laws. The computational formula of the explosive loading quantity in water pressure blasting demolition has been derived from the conditions of structural destruction. A geometrical relation equation, which should be satisfied among the neighboring explosive packages, has been obtained under the special condition of multi-package arrangement over the same circumference in a vessel.(4) As to the theory of blast testing technology, the paper discusses the testing fundamental of slit speedy smear photography. For the first time it puts forward the formula for calculating the velocity and projection angle of the two-dimensional motion particle, which makes the study field of slit speedy smear photography develop from mono-dimension to two-dimension.(5) As to the experimenting study of cumulative charge explosion, the study sets up a system of biplane mirror with a angle. And the system has been used to study the movement of the particles on the inner surface of cone-shaped cover. For the first time, it records the real movement of particles and achieves the exponent accelerating law of the particles movement.(6) In the theoretic calculation of blast projection angles, the same hypothesis with P.C.Chou and J.Cardeone has been adopted and an identical calculating formula with P.C.Chou and J. Cardeone's has been obtained by using strict integral.(7) Terrific blasting effects have been reaped through reasonable choice of explosive quantity,...
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