总结了预应力锚索的预应力变化规律以及影响预应力变化的各种因素，基于岩体流变和锚索松弛的耦合作用，推导了锚索预应力变化的数学模型。该模型反映了锚索预应力变化的实质，可较精确计算锚索预应力的变化情况，并能预测锚索的最终有效预应力。该模型工程应用证明锚索预应力的计算值与实测值相当接近且变化规律基本相同。

Prestressed cables are widely used in reinforced concrete work of geotechnical engineering. In this paper, prestress change laws and factors influencing prestress change are studied systematically, and a model predicting the prestress loss is built based on the coupling of rock mass creep and relaxation of prestressed cable. This suggested model can predict prestress loss and the final prestress of prestressed cable, and is proved from an engineering illustration that calculated values obtained by authors formula rather approach to measured data and their change laws are similar. 