Computer simulation on the uplift behavior of an arrayed under-reamed anchor group in dense sand

Abstract

Numerical simulation technology is extensively employed to resolute many difficulties of infrastructures. On the other hand, anchors have been broadly served as earth structures, especially in deep excavations. Practically, anchors are customarily served in a group. An under-reamed anchor has the outstanding short length and high anchorage capacity. This study used both the numerical and tested results to elucidate the axial loading behaviors of arrayed under-reamed anchor groups with various overburden depth in dense sand. This study adopted a constitutive law that includes strain hardening/softening and volumetric dilation, entitled SHASOVOD model, together with the computer simulation software FLAC3D to carry out the evaluation on the arrayed anchor groups. Examination results reveal that the loading curves estimated numerically are closed to those surveyed experimentally. The end bearing-displacement curve of a shallow anchor differs from that of a deep anchor. The interfering prompted by the 2∗2 arrayed anchors is less than that persuaded by the 3∗3 arrayed anchors. Besides, the interferences resulted from shallow anchor groups were slightly significant than those of deep anchor groups. When the pitches between the anchors in the group are 4D (D denotes an anchor's diameter), the yielding soils around fixed length of each anchor were extremely overlap. The average ultimate load of 3∗3 anchors was significantly less than that of a single anchor, the efficiencies of anchor groups are 75% and 80% for shallow and deep anchors, respectively. The overlaps of yielding soils decline when anchors' pitches increase. When the anchors' pitches were 10D, the behavior of individually anchor in the anchor group tends to that of a single anchor for both shallow and deep anchor groups.