Field tests on anchorage mechanism of wood bolts for conservation of earthen sites

The researches on anchorage mechanism of wood bolts are of great value to the excavation of traditional materials and crafts and the current conservation of earthen sites. Taking a typical earthen site (Jiaohe ruins) as an example, field anchorage tests are carried out, including survey of anchorage performance and monitoring of shear strain on the first interface (bolt vs. grout) of the anchorage system. The test results shows that (1) there are huge differences among wood bolts due to their natural selection, however, the anchorage can afford enough forces; (2) during loading, the shear stress varies non-uniformly with peaks along the interface; (3) with the increase of the load, the peak of shear stress shifts gradually toward the end of bolt; (4) apparent shearing expansion improves anchorage performance; and (5) the anchorage of wood bolts exhibits the features of tension-type and compression-type.