Study On The Technology To Clear Up The Shallow Point And Adverse Effects Of Underwater Reef Blasting

The construction technology of underwater rock blasting is widely used in thewater conservancy, hydroelectric and waterway engineering. The constructiontechnology is very mature. But it is very difficult to control the construction quality,because the difficulty of underwater construction is very big. Such as the fragmentationof rock is too large, or there are some shallow points in the construction area. The mainway to reduce the cost of rock blasting engineering is reduction of the shallow point.Direction at the geological conditions the technology of eliminate the shallow point ofunderwater rock blasting is explored to control the broken fragmentation and theshallow point to deduce the secondary blasting quantity and shorten the duration and thecost. It has very important practical significance. In this paper, through the theoreticalstudy and field practice of underwater rock blasting engineering the blasting parametersoptimization and harmful effects are researched combined with the comprehensiveanalysis of research status at home and abroad and the second phase of underwater rockblasting channel engineering on GuLei XiaMen.By the research on the blasting mechanism in rock blasting underwater engineeringit is founded that in the deep water the thickness of strata, crack size, crack density andthe number of the free surface will affect the rock fragmentation, the broken piece ofevenness and the difficulty of blasting. At the same lithology, when the drug unitconsumption increase the blasting block level will decrease, and followed the increaseof the depth of the underwater the explosive consumption should increase. Howeverwhen the consumption is increased to a certain degree, the change of the blasting blockis not big and it will only increase blasting damages. In the situation of the same unitconsumption of underwater blasting, water is thicker, water resistance is bigger. Theblock of blasting will greater and the blasting effect will more poor. Therefore, thestructure of rock mass, the appropriate consumption of different depth and differentlithology will be the scientific basis to optimize the blasting scheme and design theparameters of blasting. In this paper numerical simulation also has been done to the rockdynamic response of underwater rock blasting engineering. By the analysis to thenetwork parameters of the deep hole blasting, the distribution form of hole, the chargingmethod, the charging structure, the design of network and the initiating system, blastingparameters are further optimized.The hazards of underwater rock blasting engineering come from the water wave, the seismic wave and the flying rock blasting. Compared with land blasting, underwaterengineering blasting not only damage the construction, but also the influence to thesurrounding environment is very serious. In the underwater blasting the strength ofseismic effect will have more greatly improved, and the hazards of the water wave exist.The propagation of water wave in the water has some characteristics of the big impulseand the slow attenuation. There are study of the feature and propagation law of waterwave, the blasting vibration propagation law and the earthquake effect in the underwaterrock blasting engineering.In the second phase of underwater rock blasting channel engineering on GuleiGang Xiamen, through the optimization of the hole nets parameters, improvement ofcharging structure, increasing of the drilling depth, it has obtained the good blastingeffect. The blasting block and the loose degrees meet dig equipment requirements. Theaverage large rate was3.5%that it is reduced30%than the origin, and the shallow pointrate fell to2%from8%. It is greatly shorten the construction period, reduction theconstruction cost and ensuring the construction safety.