Chapter 5: Mechanics of rock blastingContents5.1Fundamental theoryofrockfailure5.2Blastingaction ofsingle charge5.3Blastingactionofextendedcharge5.4 Characters of rockfailure when detonatingmulti-charges5.5Principleof energy balanceand charging calculation5.6Maininfluencingfactorsonblastingeffect2016/11/9Chapter5:Mechanicsof rockblasting
2016/11/9 Chapter 5: Mechanics of rock blasting 2 Contents Chapter 5: Mechanics of rock blasting 5.1 Fundamental theory of rock failure 5.2 Blasting action of single charge 5.3 Blasting action of extended charge 5.4 Characters of rock failure when detonating multi-charges 5.5 Principle of energy balance and charging calculation 5.6 Main influencing factors on blasting effect ：
Section 1:Fundamental theory of rock failure （1)ExpansiveactionofexpansiongasesHTensile action ofreflectivestresswaveComprehensiveactionwithExpansionof explosiongasesexpansionandtension2016/11/9Chapter5:Mechanicsofrockblasting
2016/11/9 Chapter 5: Mechanics of rock blasting 3 Expansion of explosion gases Expansive action of expansion gases Tensile action of reflective stress wave Comprehensive action with expansion and tension Section 1: Fundamental theory of rock failure（1）
Section 1:Fundamental theory of rock failure （2)ExpansiveactionofexpansiongasesTensileactionofreflective stresswave(a)(b)Tensileactionofstress wave reflectionComprehensiveactionwitWavefrontofincidentpressurewavea)expansion andtensionWavefrontofreflectivetensilestresswave(b)R2016/11/9Chapter5:Mechanicsofrockblasting
2016/11/9 Chapter 5: Mechanics of rock blasting 4 Tensile action of stress wave reflection Expansive action of expansion gases Tensile action of reflective stress wave Comprehensive action with expansion and tension (a) Wavefront of incident pressure wave (b) Wavefront of reflective tensile stress wave Section 1: Fundamental theory of rock failure（2）
Experiments for testing tensile actionofreflectivestresswave一blastingexperimentblastingexperimentofplatedetonation experiment of1blastholeof rock bars2-crushedzonecementplate3--tensilezone 4vibrativezonewavefrontofairshockwave2--wavefront ofshockwaveincementplate-cementplate2016/11/9Chapter5:Mechanicsofrockblasting
2016/11/9 Chapter 5: Mechanics of rock blasting 5 Experiments for testing tensile action of reflective stress wave detonation experiment of cement plate 1—wavefront of air shock wave 2—wavefront of shock wave in cement plate 3—cement plate blasting experiment of rock bars blasting experiment of plate 1—blasthole 2—crushed zone 3—tensile zone 4—vibrative zone
Section1:Fundamental theoryofrockfailure （3)Expansiveaction ofEssenceofcomprehensiveaction:expansiongasesTheinitial crackisproducedbyshock wave and stress waveandfilledwithexplosiongaseswhichforcethecracktogrowfurther with quasi-static pressure.Quasi-static energy,produced by explosion gases,is the mainforce of rockfailure.Tensile action ofByA.H.XaHykaeB,three classificationsof rock:reflectivestresswave(1)Rockofhighimpedance(MPa·s/m),from15to25,isfailedmainbyincidentandreflectivestresswave(2) Rock of medium impedance, from 5 to 15, is failed mainlybycomprehensiveactionofincidentstresswaveandexplosiongases.Comprehensiveaction withexpansionandtension(3) Rock of low impedance, lower than 5, is failed mainly byexpansiveaction ofexplosiongases62016/11/9Chapter5:Mechanicsofrockblasting
2016/11/9 Chapter 5: Mechanics of rock blasting 6 Expansive action of expansion gases Tensile action of reflective stress wave Comprehensive action with expansion and tension Essence of comprehensive action： By A.H.XaHyKaeB , three classifications of rock : (1) Rock of high impedance(MPa·s/m), from 15 to 25, is failed main by incident and reflective stress wave. (2) Rock of medium impedance, from 5 to 15, is failed mainly by comprehensive action of incident stress wave and explosion gases. (3) Rock of low impedance, lower than 5, is failed mainly by expansive action of explosion gases. The initial crack is produced by shock wave and stress wave and filled with explosion gases which force the crack to grow further with quasi-static pressure. Quasi-static energy, produced by explosion gases, is the main force of rock failure. Section 1: Fundamental theory of rock failure（3）