Simulation of dynamic failure process of horizontal thick-layered rock slopes using particle flow code
HU Xunjian1，BIAN Kang2，LI Pengcheng1，CHEN Lingzhu1，LIU Zhenping2
(1. Faculty of Engineering，China University of Geosciences(Wuhan)，Wuhan，Hubei 430074，China；2. State Key Laboratory of Geomechanics and Geotechnical Engineering，Institute of Rock and Soil Mechanics，Chinese Academy of Sciences，
Wuhan，Hubei 430071，China)
Abstract：The failure modes，dynamic response and stress evolution characteristics of the thick-layered rock slopes with the non-persistent joints in different combinations of rock-bridge lengths and joint spacing were studied based on the two-dimensional particle flow code PFC2D. The results show that the main failure modes of the horizontal thick-layered rock slopes with non-persistent joint under the action of earthquake are collapse failure，tensile-sliding-block toppling failure and tensile-horizontal sliding failure. The horizontal non-persistent joint is the key factor to control the dynamic stability of the slope. The joint spacing plays a controlling role in the failure mode of the slope. When the joint spacing is small，the collapse failure is easy to occur. When the joint spacing is large，the tensile-sliding-topping failure and tensile-horizontal sliding failure occur normally. The length of rock bridge and joint spacing control the degree of rock fragmentation of slope and the number of sliding surfaces when slope fails. When the joint spacing is narrow or when the joint spacing is wide and the length of rock bridge is short，the single sliding failure occurs. When the spacing of the joint is wide and the rock bridge length is long，the double sliding surface damage occurs. Under the action of earthquake，the rock bridge section breaks down at first，and then the joints also produce damage and coalescence. The length of rock bridge and the width of joint spacing have a certain influence on dynamic response of slope. The peak displacement and peak velocity increase as the decrease of joint spacing and the increase of the length of rock bridge. The area with the PGA magnification factor influenced is concentrated at the slope toe and on the slope surface. The stress evolution in the rock-bridge of the slope has a good agreement with the acceleration of the input seismic wave.
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2017, Vol. 36 
