丹江口水库大坝加高工程应力分散型预应力锚杆研制及应用

Development and Application of Stress-dispersion Pre-stressed Anchor Rod in the Danjiangkou Dam Heightening Project

介绍了丹江口水库大坝加高改造工程中采用的应力分散型、自锁式内锚头预应力锚杆技术。项目研制了性能可靠、结构合理的专用扩孔器具和自锁式内锚头,解决了50 m深孔高精度钻孔难题。该锚固技术改善了内锚固段应力集中的不良状态,改变了普通锚杆预应力通过内锚固体与孔壁的粘结力传递到承载体上的方式,而是通过在扩孔段设置的自锁式内锚头,以压力的形式,分散直接作用于不同深度的承载体上,锚固力不会因粘结力衰减而损失,起到长期锚固的作用。

This paper introduces the stress-dispersion and self-locking type pre-stressed anchor rod technology used in dan- jiangkou dam heightening project. The special reaming tools and self-locking type anchor with reliable performance and rea-sonable structure were developed to complete the difficult 50m high precision drilling in the project. With this anchorage technology, stress concentration in the inner anchorage section was improved; ordinary anchor pre-stress transmission to base through bonding between inner anchorage body and hole wall was changed by the use of self-locking inner anchors designed for the hole enlarged sections with dispersed pressure directly applying on the base at different depth. In this case, the anchoring force will not lose along with bond force decreasing, lone-term anchoring can be ensured.