Based on representative blasting engineering projects，the development history of engineering blasting in China since 1950’s was reviewed，three development phases were summarized，main achievements in fundamental theory，engineering practice，scientific study and industry organization of engineering blasting in each phase were described briefly. Finally，prospective to engineering blasting development direction is given.
Precision blasting，which is different from traditional control blasting，is regarded as the signs of new development stage of engineering blasting. The definition，connotation，technology system and current situation of its application and development were described briefly. With regard to the prospect of precision blasting，following aspects for further study are recommened：a. a multiple disciplinary study should be developed for a more understanding on the explosive energy release and quantitative blasting design；b. according to requirements of digital blasting objective，syncretic study of precision blasting and technology should be enhanced；c. numerical simulation was an important tool for optimizing engineering blasting scheme and blasting adverse effects control，a more elaborate precision numerical simulation methods should be studied furthermore；d. the modernization and standardization of precision blasting construction should be enhanced.
The applications of numerical simulation in demolition blasting were reviewed. Several methods of numerical simulation in demolition blasting were introduced. The strength and weakness of the numerical methods mentioned in this paper were also indicated，respectively. Furthermore，the solid lattice model in the frame of discrete element method（DEM），which was developed by the author and his team，was detailed described. The existed problems in the current numerical simulation methods of demolition blasting were presented and the future trend of the numerical simulation is finally prospected.
Reasonable rock-explosive matching is of great important to the enhancing of explosive energy effective utilization and the improving of rock fragmentation effect. The traditionally emphasized method of acoustic impedance matching is not reasonable. Starting from the blasting breakage mechanism, a new method of rock-explosive matching in drilling and blasting is proposed. The new approach chooses explosive parameters by reasonable control of the size of crushed zone under the condition of fully fragmentation between adjacent balstholes. This method can intuitively reflect the blasting fragmentation effect and energy effective utilization, which is easy to implement. Also, a modified model is developed, with the combination of adjacent blastholes explosion load taken into account. As a result, explosive parameters for different grades of rock are given in full coupling on-site mixed explosive charge under different project objectives.
This paper numerically simulates the stress development and generates a three-dimensional model of the medium-deep hole blasting in infinite rock mass for continuous charge and divided charge in blasting by using the large-scale nonlinear dynamic analysis software LSDYNA and the elastic- plastic model *MAT_PLASTIC_KINEMATIC and JwL. The difference of the decreasing rate in Von Mises effective stress of blasting，element effective stress peak in free face，the bore wall stress and acceleration are investigated. It is shown that divided charge could greatly improve the blasting effect by engineering blasting practice.
The geology condition of Xiang jiaba hydraulic power station underground workshop is very complicated. Characteristics of crane beam of rock wall construction embodied in width of rock bench, huge bearing load, high quality requirements, urgent construction period and so on. According to inherent conception of “precision blasting”, technological measures of optimized excavation sequence, steel tube frame for drilling, double smooth blasting, equal and minim explosive and plum blossom shaped holes were adopted in construction. Through which, precision control of explosive energy release and rock fragmentation were achieved, insured the blasting excavation quality. Half-hole rate in Ⅱ surrounding rock was 100%, in Ⅲ surrounding rock was 99.2%, in Ⅳsurrounding rock was 90~97.3%, the phenomenon of under break was avoided absolutely, the average over break value was only 2.9cm, the non-smoothness is 0~4cm, the influence depth because of blasting excavation unloading was 0.2~0.7cm, the excavation effect was nearly perfect.
The scallop moderate longhole blasting mining method in Da Hong-shan copper mine applications accounted for more than 61% of the total amount of mining, but the large output rate restricts the mines for ore strength, The average lump ore as high as 22.7%. In order to realize the mine production efficient development, the circular moderate longhole blasting technology and field test. The test results show that circular hole blasting can reduce the block rate is reduced to 10.3%, and the traditional scallop moderate longhole blasting mining compared with the average lump ore decreased by 12.4 percentage points. The panel on duty for the day ore quantity increase 152.31t, increase rate is 51.1%. Reduces the handling of large time delay and secondary crushing of explosives and the consumption of detonators, the efficiency of drawing and at the same time, reduce the mining cost ,achieved good blasting effect.
Analyzed the reasons and mechanism of blasting flyrock in weak interlayer,combined with weak interlayer impact generated by blasting flyrock to distinguish the differences of flying stone generated in the conditions of weak interlayer and general. In weak interlayer and urban area complex blasting environment, reasonable and effective control measures of blasting flyrock are given.
Reduce the blasting vibration is important for blasting excavation in subway tunnel construction. Take the 3rd bid section of Line 3 of Qingdao subway project for example, the distance between tunnel vault and ground is 5~8m, in order to insure the safety of the upper buildings, technologies of parallel cut with big empty hole, one-time initiation and delay by parts, and multiply short holes were adopted in the project. The results show that the maximum value of vertical vibration limited in the criterion allowance, and the upper buildings was intact. Besides, problems of shock conducting tube detonator delay number difficulty to meet large cross-section tunnel blasting excavation requirements, multiple cross-section can’t initiation simultaneous, and low construction efficiency were solved, which ensure the construction safety and schedule.
Key technologies of precision blasting were put forward based on characteristics of urban viaduct blasting demolition in complicated surroundings. Initial bending instability mechanics model of reinforcing steel bar frame of blasting fragmented pier and sequenced collapsed dynamics model were established for quantitative blasting design. Technologies of water pressure blasting were applied in multi-cell box girder fragmentation. The initiation network of non-electric duplication crossover was adopted for safety and reliability of ultra-long delay. The rationality of blasting scheme and parameters were validated by physical model test. Adverse effects were forecasted and controlled by integrated protective technologies. Specialization cooperation，precision，execution（SCPE）project management method was put forward for precision management. Key technologies of precision demolition blasting can provide reference for similar projects.
Non-electric initiation system was the only initiation system for viaduct blasting demolition. Aimed at the application actuality, the relay point characteristicof multiple parallel detonator initiation system was studied in the paper, and the simple formula for mean value of the relay point initiation time was put forward. Reliability standard for non-electric initiationsystem of different scale was established. Duplex-cross non-electric initiation systemwas invented, which not only can avoid side roll in the viaduct collapse process, but also can elevate the reliability of the relay point. Research achievements can provide theoretical basis for viaduct blasting demolition initiation system design.
Experimental investigation was conducted for the dynamic response of a real spherical explosive chamber that can simulate 200m deepwater explosive loaded 10gTNT equivalent．The vibration characteristics and dynamic strength of the chamber was analyzed by measuring the strain profiles of six typical points on the chamber．The research results reveal the rule of the dynamic response of the container on different explosive load and static pressure．It provides reference for the design and development of the vessel to simulate deepwater explosion.
Emulsion explosive possess favorable water-resistance performance, storage performance and detonation stability, has been widely used in all over the world.Development actuality and production technique characteristics of emulsion explosive in china were introduced firstly. Took into account of technique characteristics of packaging emulsion explosive, major hazard sources of emulsion explosive production line were analyzed. Finally, prevention measures based on inherent safety of emulsion explosive production were put forward.
With mine-field blasting examples meeting the needs of protected object safety demonstration for a long time, systematically analyze the impact of blasting vibration to bridges, tunnels and slopes, etc., also the mechanical relationships between each other. Using of risk analysis principles put forward safety demonstrating method and hazardous factors controlling technique, and establish the common procedure of blasting parameters zoning control to realize a standardized process control system. The technology has been gradually improved after several applications.
To analyze the ground vibration caused by blasting demolition of urban overpass, in this paper we introduced the measurement method and then studied the characteristics of recorded ground vibrations. Through analysis of peak acceleration, peak frequency and duration, results indicate that, the vertical component of vibration is the most important in the region close to the collapse point; the collapse of bridge segments will lead to superposition of ground vibration, and isolation measures can reduce the peak acceleration but increase the duration of vibration; blasting and collapse vibration cause no damage to the reserved structure which indicates that blasting description is a safe and effective method.
A synthetic method, which combines theoretical model and field measurement data was put forward to predict vibration effects induced by impact loading. A series of targeted field measurements were proceeded by hammer impact tests. The Anderson model was modified and verified by the data measured in field hammer impact tests. Then the impact induced vibration was predicted using the modified Anderson model. Finally, the prediction results were compared with the measured results. The results indicates that the prediction results approximately approach to the measured results.
Taking underwater reef blasting in Gulei sea channel of Xiamen Port as an example, the forming characteristic of shock wave in water for underwater drilling blasting is analyzed. By field monitoring, the pressure of shock in water for different distances is attained, the major parameter, such as pressure amplitude and positive action time, and the propagation attenuation rule of shock in water are researched in this paper. The result can helpful for engineering design and construction and environmental safety assessment.
Application of transient electromagnetic method, carries on the cavern blasting blind detection and recognition of feasibility study. Test to establish the electromagnetic background field, and then in the cavern preset benign conductor and measured after eliminating the background field, in the electromagnetic field transient to do the electromagnetic measurement again after blasting. Benign comparison before and after blasting preset the change of the conductive body eddy current field, realizes the cavern blasting blind shot detection and identification of purpose. The test results show that the target when the aluminum box buried depth of no more than 30 m, transient electromagnetic method can clearly identify the position of the aluminum box; When the aluminum box buried depth after more than 30 m, aluminum box formation of the secondary vortex field level, not sure the deep buried depth and position of the aluminum box.