大岗山水电站预防接缝灌浆下层灌区增开的改进工艺

Improvements on Joint Grouting Technology for Preventing the Re-opening of Lower Grouting Joints in Dagangshan Hydropower Station

大岗山水电站施工过程中拱坝接缝灌浆已灌区横缝出现二次增开问题。初步分析认为,在接缝灌浆过程中,仅仅考虑灌区的灌浆压力与缝面增开度,而忽视了下层已灌区的缝面增开度,可能是导致下层已灌缝面增开的主要原因。为此,大岗山水电站及时调整思路,在后续接缝灌浆过程中采用接缝灌浆改进工艺,成功降低了横缝的二次增开率,且灌浆质量未受影响。

The transverse joints in grouted areas of joint grouting are opened again in the construction Dagangshan Arch Dam. The preliminary analyses consider that the re-opening of grouted joint may be mainly caused by just focusing on the grouting pressure and the re-opening degree of grouting area and ignoring the re-opening degree of lower grouted area in the process of joint grouting. Therefore, the joint grouting technology is improved and then used in following process of joint grouting. The application of improved technology successfully reduces the rate of re-opening of following transverse joints and the quality of grouting is not adversely affected.