Investigations of rock anchor corrosion and its influence factors by exhumations in four typical field sites

Abstract

With the abundance application of rock and soil anchors in high slope and underground projects, more concerns have been paid to the working condition and durability of the anchorage system. To effectively evaluate the corrosion of anchors in service and the influence factors, field exhumations were performed in four typical application sites and tests of samples were conducted in laboratory. Chemical composition, metallurgical structure and mechanical performance of anchors are tested. Microstructure and component of corrosion byproducts and grout were analyzed. The environmental influence factors are also assessed. The results demonstrate that the anchor head is most liable to corrode in comparing to other section of the anchor. Presence of damaging ions can accelerate the initiation and development of corrosion. Chemical and mechanical properties of anchors remain basically unchanged after 1.5 to 20 years' service. Groundwater and stray currents in the underground do not induce noticeable influence on the corrosion of anchors. This research accomplished a set of evaluation methods of influencing factors and the general law of anchors' corrosion in field environments, which may provide a reference framework for evaluating the environmental effects, durability and service life of rock anchors.