中文摘要：

喜儿沟水电站大型调压井采用沉井法施工。考虑到沉井结构尺寸大，且位于漂卵砾石复杂地层中，在下沉施工中采用爆炸助沉法，通过冲击波超压的交替升降使井壁振动产生下沉，从而解决下沉受阻难题。针对喜儿沟工程实例，通过算理论计算和动力有限元数值模拟，分别得到沉井不发生破坏的炸药最大允许用量分别为171.13kg和74.87kg。在实际工程中采用小药量助沉可以在保证施工安全前提下，完成施工任务。

英文摘要：

The large surge shaft of Xi’ergou Hydropower Station constructed with open caisson. The open caisson has a large structure and is located in complex strata of pebbles gravel, so it used explosion method to solve the problem of the subsidence blocked in sinking construction according to the shaft lining sinking by vibration made by the shock wave overpressure’s decrease and increase alternatively. Rely on the project of Xi’ergou, in case of the damage of open caisson, it got the maximum amount of explosive allowed is 171.13kg and 74.87kg by calculating the peak value of overpressure according to theoretical analysis and numerical simulation. Using explosion method to help sinking by small amount of explosive can complete the construction tasks by the premise of the guarantee of construction safety in practical engineering.