The loss of anchoring force is one of the problems to be solved urgently. The anchorage loss is a key factor causing the failure of anchoring engineering, so it is crucial to study the time-dependent variation of anchoring force. Alternating dry and wet (D-W) conditions have a significant effect on deformation of rock. The anchoring system is composed of anchoring components and rock mass, and thus rock deformation has a significant impact on the loss of anchoring force. Quantifying rock deformation under the effects of D-W cycles is a prerequisite to understanding the factors that influence loss of anchoring force in anchor bolts. In this study, we designed an anchoring device that enabled real-time monitoring of the variation in strain during D-W periods and rock testing. Nuclear magnetic resonance (NMR) measurements showed that under D-W conditions, the increment in porosity was smaller for prestressed rock than unstressed rock. The trends of prestress loss and strain variation are consistent, which can be divided into three characteristic intervals: rapid attenuation stage, slow attenuation stage and relatively stable stage. At the same stress level, the rate of stress loss and strain for the soaking specimen was the highest, while that of the dried specimen was the lowest. In the same D-W cycling conditions, the greater the prestress, the smaller the strain loss rate of the rock, especially under soaking conditions. The characteristics of pore structure and physical mechanical parameters indicated that prestress could effectively suppress damage caused by erosion related to D-W cycles. The study reveals the fluctuation behavior of rock strain and prestress loss under D-W conditions, providing a reference for effectively controlling anchoring loss and ideas for inventing new anchoring components.

锚固力损失是亟待解决的问题之一。锚固损失是造成锚固工程失败的关键因素，因此研究锚固力随时间的变化至关重要。干湿交替（DW）条件对岩石变形有显着影响。锚固系统由锚固构件和岩体组成，岩石变形对锚固力损失有显着影响。量化 DW 循环影响下的岩石变形是了解影响锚栓锚固力损失的因素的先决条件。在这项研究中，我们设计了一种锚固装置，可以实时监测 DW 期间和岩石测试期间的应变变化。核磁共振（NMR）测量表明，在DW条件下，预应力岩石的孔隙率增量小于无应力岩石。预应力损失和应变变化趋势一致，可分为快速衰减阶段、慢速衰减阶段和相对稳定阶段三个特征区间。在相同应力水平下，浸泡试件的应力损失率和应变率最高，而干燥试件的应力损失率和应变率最低。在相同的DW循环条件下，预应力越大，岩石的应变损失率越小，特别是在浸泡条件下。孔隙结构和物理力学参数特征表明，预应力可以有效抑制DW循环引起的侵蚀损伤。该研究揭示了DW条件下岩石应变和预应力损失的波动行为，为有效控制锚固损失提供参考，并为发明新型锚固构件提供思路。