预应力技术在中缅天然气管道跨越施工中的应用

大型管道悬索跨越的锚固墩多采用混凝土结构,随着跨度及载荷的增加,将引起锚固墩混凝土受力增加较快,采用传统锚杆形式的锚固结构可能会引起混凝土开裂,降低锚固寿命,而预应力结构可以有效提高跨越锚固效率,减少工程投入。为此,在中缅天然气管道跨越施工中,应用预应力技术,结合管道跨越的结构及荷载特点,通过在锚碇中增加隧道锚等预应力结构,并采用定位方式、锚固结构、混凝土浇筑、张拉、介质注入等优化措施,建立了一套有效的预应力锚固系统,延缓了混凝土裂缝的出现,提高了结构的耐久性及锚固效率。该技术在中缅天然气管道跨越工程中得到了成功运用,取得了良好的经济效益与社会效益,表明该技术是悬索跨越锚固结构优化的一条有效解决途径,丰富了跨越锚固结构类型,为管道跨越结构规模发展提供了技术支撑。

Application of pre-stressed technology in the China-Myanmar cable-suspended gas pipeline crossing construction

Concrete structure has been commonly applied in the anchorages of a large cable-suspended pipeline crossing construction. But with the increase of the span and bearing load, a rapid rise of stress on the concrete anchorages will occur. Concrete cracking will inevitably occur and the anchorage life will be surely reduced to a large degree if the traditional anchoring structure fixed by anchor rods is still employed. To solve this problem, the pre-stressed structure was suggested to effectively improve the efficiency of spanning anchors and reduce the engineering cost. This technology was applied in the China-Myanmar cable-suspended pipeline crossing construction. And in combination with the spanning structure and load features in this project, tunnel anchorage was added in the anchors and some optimal measures were taken in such aspects as the positioning way, anchorage structure, concrete placement, prestressing, medium injection, etc. On this basis, a set of effective anchorage system was built up to delay the occurrence of concrete cracking and enhance the stress durability of the structure and anchoring efficiency. This technology has been successfully applied in the China-Myanmar suspended pipeline structure project with both economic and social benefits achieved. This shows that this technology is not only an effective solution to the optimization of suspended pipeline anchorage structures, but enriches spanning anchorage structure types and provides a technical support for the development of pipeline spanning structure.