Analysis of anchorage performance on new tension-compression anchor Ⅲ field test

The new tension-compression composite anchor (TC-anchor) is developed to overcome the shortcomings of the traditional tension anchor (T-anchor), such as stress concentration, insufficient bonding strength between anchorage body and soil mass, and low uplift bearing capacity. The bearing capacity, load-displacement curves and strain data of T-anchor and TC-anchor are analyzed, based on the field destructive tests. The results show that the average destructive loads of three groups of TC-anchor, TC12 -3, TC11-1 and TC21, increase to 2.81, 2.01, 2.52 times those of T-anchor, respectively. The maximum tension loss rate in the rebar hole is 20.5% and only 6.8% along the free anchorage length, and therefore the tension loss occurs mainly along the compression anchorage body (CAB). The tension anchorage body (TAB) length of TC12-3 anchor is the shortest, and therefore the bearing loads of unit TAB length are the highest. The CAB length of TC21-1 anchor is the shortest, and therefore the bearing loads of unit CAB length are the highest. When the anchor is destructed, the tension bearing coefficients of TC12-3, TC11-1, TC21-1 are 0.398, 0.470, 0.600, respectively, and the CAB and TAB of TC11-1 are destructed at the same time, while those of TC12-3 and TC21-1 are destructed successively. The significantly increased anchorage performance of TC-anchor is mainly due to the decomposition of the loads, the two-way transmission mechanisms of the interface shear stress and the bearing effect of short anchor. It can be seen from the load-displacement curves that the TC-anchor has better deformation-resisting capability. Therefore, it has significant advantages and broad application prospects in geotechnical anchorage engineering.