MODEL TEST RESEARCH ON FAILURE MECHANISM OF UNDERREAMED GROUND ANCHOR
GUO Gang1，2，LIU Zhong1，2，LI Yongkang3，YANG Song1，2，ZHANG Yi 1，2
(1. Central Research Institute of Building and Construction of MCC Group，Beijing 100088，China；2. China Jingye Engineering Corporation Limited，Beijing 100088，China；3. China Metallurgical Group Corporation，Beijing 100020，China)
Abstract：The rupture surface of underreamed ground anchor is essentially important for the bearing mechanism of underreamed ground anchor. In order to observe the shape of rupture surface of sand around underreamed ground anchor during uplifting，a series of model tests on underreamed ground anchor under vertical uplifting were carried out with digital photogrammetry. For the first time，the whole deformation fields of underreamed ground anchor were captured through digital deformation analysis. The results show that the shear bands in the whole process exhibited as long and narrow vertical strips. The shear strain amplitude inside the rupture surface increased. During the process，the sand above the top surface of underreamed section exhibited volumetric compression；while the volume of sand on the side of underreamed section expanded. Based on the analysis，the damage model and bearing capacity calculation method of underreamed ground anchor should be established according to the rupture surface through actual observations.
2013, Vol. 32 
