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л??壬????????? ??
(?????????????????????????????232001)
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?????????TU746.5 ????????A
BLASTING DEMOLITION OF A REINFORED CONCRETE WATER TOWER
XIE Rui-feng??FU Ju-gen??ZONG Qi
(School of Cizil Engineering??Anhui University of Science & Technology??Huainan 232001??Anhui??China)
ABSTRACT?? According to its structural characteristic and surrounding environment??the reinforced concrete water tower was subjected to a directional blasting demolition towards the northeast??The desiredblasting result was reached by taking trapezoidal blasting incision??selecting reasonable blasting parameters??adopting milliseconds delay initiation network to reduce blasting vibration??making vibration calibration of blasting and collapse??and taking effective protection measures??
KEY WORDS?? Reinforced concrete water tower??Directional blasting??Blasting parameters??Protectionmeasures
1 ??????????Χ????
1.1 ??????
??????????????????????50m???????????????????????????????????????????????????ɡ?θ?????????????????2.5m?????200mm??????????????????20mm?????ü??200mm?????й???10mm??????????1??????????????????????????????????2.0m????0.6m??
1.2 ??????
??????????????У???????????????50m??????????38m?????????72m????????20m??????????????60m????????????????l?????????????????????????????1??2m??????Χ???Χ????е?·??????????Χ???????1?????
?1 ?????Χ???????? (??λ??m)
Fig.1 Scheme of the environment aroundthe water tower
2 ??????????
???????????????????????????????????????Χ??????·??????????????????????????????????Ψ???????????????ж???(???????60m)?????????????????????????????????????????15˚???????????????????????????г?????????5m??
3 ??????????
3.1 ?????п?
(1)?????п?λ???z1?{???????????????????????????и??????????????????????????????????λ????????0.5m???п??????????Ρ?
(2)?п???h?z2?{???????????????????????????????????????????h=(4??8)??=1.2m?????????????????200mm??
(3)?п?????L=(0.55??0.65)S=4.3m?????S????????????7.85m?? ??????п???????????????????????????ε???????????400mm?????500mm???г???䶮?????п????????2?????
3.2 ???????
??????Lb=(0.60??0.70)??=130mm??????a=200 mm?????b=200 mm???п??÷???β???7?????????????
?2 ?????п??????????
Fig.2 Sketch of blasting cut anddirectional??windows
?????????????????????Qb=qab??=20g?????q?????????q=2000??2500g/m3??
3.3 ??????·???
????????????????????????÷綯????????(??????38??40mm)??????黯????MFB?150????÷?????????????????????÷???????????????????????·????????????????MS2??MS4??MS5?κ?????????????·????????????????
4 ??????????
4.1 ???????z3?{
??????????????????????????????????????????????У?????????????
R=(K/??)1/??Q m (1)
??У?R????????????????????????????m??Q????????????????????????????????kg??m??????????m=1/3??????????????????????????=1??2?????????????????????????????=7cm/s??K????????????????ε??????й???????????K=200??300??
??????????????????????÷?κ???????????????????????????????????Χ????????????????????????????????????????????????????????????????????ú??????????
4.2 ????????z4?{
(1)??????????????????????????????????????????????????????????Ч??????????????????????????????????????????????????
(2)??????????Χ?????????????Χ?200m?????????????????????????ж??????????????·?????????????У?????????????????????????????????????????С?
5 ????Ч??
???????????彫???????????????6m????????5s??????????????????????????????????????????????????6s????????????????????????????????????ви??????????????????????????????????????????????????????????У?????????????????????????С????Χ????????·?????????????????????Ч????
?ο??????
[1] ??????????????????????????????[M]??????????????????磬2008??
[2] ???????????????????????????????????п??????????[J]??????????2006??12(2)??56??58??
[3] ?л?????????????????????(GB6722??2003)[s]?????????й?????????磬2004??
[4] ????????????????????????????п???????????λ????????[J]??????????2005????(4)??46??49??
[5] ?????????????????·???????????????????????[J]???????2007??24(4)??58??59??