三峡临时船闸　升船机基础槽挖爆破

Blasting and Excavating in Trenches of Foundation of the Three Gorges' Temporary Shiplock and Shiplift

临时船闸及升船机基础开挖总量达1400万m3，有效工期仅17.5个月，最大开挖高差130～140m。二者间留有均宽32m的中隔墩（保留岩体），槽挖深度分别为27m、38m，槽挖工程量分别是30万m3和50万m3。槽挖中采用高梯段、大孔距小抵抗线孔间微差爆破，配合预裂（光面）爆破，取得了成功。爆渣粒径一般为10～60cm，两侧保留岩体无爆破裂隙，原生裂隙亦无张开现象，中隔墩安然无损。

Excavation works in the foundations of the Three Gorges temporary shiplock and shiplift should be finished within no more than seventeen and a half months, with a total excavation volume of 14 million cubic meters. The maximum excavation differenec in height is 130~ 14 0m. A dividing pier (reserved rock body) was remained with an average width of 32m between the temporary shiplock and the shiplift. Excavating depths in the temporary shiplock and the shiplift were 27m and 38m respectively, with respective excavation volumes of 300 and 500 thousand cubic meters. The blasting operation was carried out successfully by means of differential blasting(adopting ways of high bench, long distance of drillholes and short resistance line), together with presplit blasting (smooth blasting) .Size of most broken stones was 40~60m. No explosion crack was found on both sides of the reserved body and no original fissure was found to be widened. The dividing pier is safe and sound.