SHEAR CREEP EXPERIMENTS FOR ANCHORAGE INTERFACE MECHANICS AND NONLINEAR RHEOLOGICAL MODEL OF ROCKS
WU Guojun，CHEN Weizhong，JIA Shanpo，YANG Jianping
(State Key Laboratory of Geomechanics and Geotechnical Engineering，Institute of Rock and Soil Mechanics，Chinese Academy of Sciences，Wuhan，Hubei 430071，China)
Abstract：Based on a large amount of tests and engineering practices，it is shown that the failure of anchorage system takes place at the interface between anchorage body and rock-soil；so it is necessary to carry out shear rheological experiments for interface mechanics of anchorage system in order to study the mechanism of grout-rock interface and the change characteristics of anchorage force during the rheological period. The results of experiments show that the shear rheological strain grows with time at the certain shear stress level，and grows sharply when shear stress level rises. Under the condition of low shear stress level，the initial rheological stage and steady-state creep stage occurs；however，the accelerating rheological stage will turn up when shear stress exceeds a certain value. With the increment of shear rheology，axial rheological strain of the anchor enhances a little and the anchorage force grows slowly. On the basis of experiment，a nonlinear empirical rheological constitutive model which has a continuous formulation is proposed，which is more reasonable because of its consideration of normal stress and its ability of describing the whole rheological process including primary rheological deformation，secondary rheological deformation and accelerating rheological deformation. For further research on feasibility of the anchorage interface rheological constitutive model，a numerical test is carried out to simulate a shear rheological experiment of sample 3 for 51 hours. It is shown that the results of numerical simulation test coincide very well with that of shear rheological experiment，so it is indicated that the proposed nonlinear rheological model is available.
