Study of coupling effect between anchorage force loss of prestressed anchor cable and rock and soil creep

The engineering accidents of anchorage failure often occur owing to the loss of anchorage force of prestressed anchor cable. Complicated coupling effect exists between the anchorage force loss of anchor cable and rock and soil creep. Theoretical foundation and technical means for the design, construction, safe operation management, the control and compensation technique of the loss of anchorage force is provided by building the coupling effect model and establishing the formula of the two. On the basis of common rheological model of rock and soil, coupling calculation model is established based on the equal strain and validated as well by means of theoretical analysis and model research. The findings are as follows: (1) The coupling effect model of anchor cable anchorage force change and rock and soil creep in line with the practical engineering is established. The relationship between the anchorage force loss of prestressed anchor cable and rock and soil creep is correctly reflected. The constitutive equation and relaxation equation and creep equation are deduced, and the calculable relationship between anchorage force change and rock and soil creep is solved theoretically. (2) With the creep equation of the coupling calculation model, the anchorage force loss of anchor cable caused by slope creep effect can be calculated when the material parameters are known. Comparatively analyzing the anchor cable stress data in the practical engineering, we can accurately understand and evaluate the abnormal changes of anchor cable anchorage force to guide the design and construction of practical engineering and ensure the safety of engineering construction process. (3) With the relaxation equation of coupling calculation model, the monitoring data of prestressed anchor cable stress state is arranged and analyzed. With the back analysis of the anchorage force loss data of anchor cable, the creep parameters of rock and soil are analyzed. The creep value of rock and soil according to the material characteristics of creep medium is calculated. The safety and reliability of prestressed anchor cable anchorage engineering are judged in accordance to the creep value to guide the safety operation management of anchorage engineering.