葛洲坝1号船闸混凝土裂缝成因及加固研究

葛洲坝1号船闸是我国目前运行规模最大的船闸,设计规模3 000 t级,闸室有效尺度280 m×34 m×5 m(长×宽×槛上水深),可一次通过万吨船队.船闸下闸首右2块下游面中部在施工过程中发现一条长达30 m的竖直向裂缝,船闸运行后,该裂缝一直处于发展状态,并已沿顶部顺水流方向贯通.根据近10 a来对裂缝的跟踪检测资料,结合下闸首混凝土施工情况和结构工作特点,对裂缝成因及危害性进行了分析,对裂缝处理原则和处理方案进行了论证,研究提出了采用预应力锚索加回填灌浆的综合处理措施,加固工程于1999年5月完成,取得了较好的效果.

Cause analysis on concrete crack of No.1 shiplock of Gezhouba hydroproject and study on strengthening

The Gezhouba No.1 shiplock is the largest shiplock at present in China, with its effective lock dimensions of 280 m by 34 m by 5 m (length by width by water depth above the sill), and a 10 000-t barge tow with single barge size up to 3 000 t can pass through the shiplock. In the construction period, a 30-m-long vertical crack was found in the middle portion of the downstream face of the right No.2 monolith at the lower lockhead. Since the shiplock's operation, the crack had been developing and had become a through one in the flow direction along the upper portion. Based on the measured data obtained in past 10 years and in consideration of the construction conditions of concrete and the structural characteristics of the lower lockhead, the cracking cause and the harmfulness of the crack were analyzed, and the principle and scheme for crack treatment were verified. Comprehensive measures for crack treatment by using prestressed anchorage tendon and backfill grouting were proposed. The strengthening work was completed in May, 1999, achieving excellent results.