延时时间对地表振动叠加效应的影响

为了得到非电雷管和电子雷管的合理延时时间进而控制地表振速，以厦门抽水蓄能电站的进场通风兼安全洞的延时爆破为背景，通过现场实测数据和理论公式分析了不同延时时间对地表振动叠加效应的影响。根据实测数据，分析了隧道掘进中毫秒延时爆破和半秒延时爆破地表振动波形的叠加效应，可知非电雷管的误差导致毫秒延时爆破中不同段的地表振动波形形成叠加；而半秒雷管虽有误差，但延时时间较大，不同段的振速波形之间相互独立。利用理论计算探讨了本工程中第1段掏槽孔和第2段掏槽孔在不同延时时间下的振动波形叠加情况，给出了叠加振速放大、叠加振速减小和无叠加产生的几种情况。依据理论和实测振速波形的叠加效应，分别提出适合本工程的毫秒延时非电雷管和电子雷管的合理延时时间，可为类似的隧道延时爆破提供借鉴。

ENGINEERING PRACTICE OF OVER-BURDEN CHAMBER BLASTING

Because of improper construction management in chamber excavation,the axial direction of a chamber has a great dviation from the designed direction,causing that the burden of charged chamber is increased from designed 40m to measured 57m.The chamber blasting with a burden larger than 50m is very rare,thus there being no referable experience.In the light of undulating topography,the pilot tunnel and charged chamber are excavated in a great slope of +172‰(approximate to 10°).With a short working term,the over-burden chamber blasting is crowned with success through reasonable utilization of the shape of excavated chamber, adjustment of linear charge's structure,position and mass,as well as increase of the end charge and adoption of dumbbell-like charge structure.