水作用下黄土土层锚杆的预应力损失

Analysis on the pre-stress loss of pre-stressed anchors in loess under water action

为研究水的作用下,土层锚杆的预应力损失,作者进行了土层锚杆抗拔模型试验。利用所得数据,得到了锚杆预应力损失随时间变化的曲线、预应力锚杆的锚头位移随时间而变化的曲线等。在对所得曲线分析与讨论的基础上,得出黄土土层锚杆的预应力损失主要是由于锚固段土层的蠕变引起的,而且随着土体含水量增加,土体的蠕变性也愈加明显,使得锚杆最终因锚固力不足而被拔出破坏。并提出施工过程中,注意排水、选择优质材料、保证安装质量,同时注重超张拉和二次张拉,是补偿预应力损失,确保工程安全性的重要手段。

The author made an uplift model test on anchors in loess, to study the pre-stress loss of pre-stressed anchors in loess under water action. On the basis of data obtained from the test, the author obtains the prestress loss of pre-stressed anchors in loess with time and the curve of pre-stressed anchors bolt head displacement with time. With focus on the analysis and discussion, the author draws a conclusion that the prestress loss of pre-stressed anchors in loess was caused mainly by creep of soil, and with the increase of soil water content, its creep was more visible, then the anchor was pulled out enough to damage. In this paper, author suggests some important means to ensure security, such as attention to drainage, selection of highquality materials, quality guarantee of installation, attention to ultra-tensioned and the second tension to compensate for pre-stress loss in construction process.