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许彬, 刘新荣, 周小涵, 刘俊, 黄俊辉, 王䶮, 曾夕. 消落带岩体劣化下顺层岩质边坡动力响应规律试验研究[J]. 岩土工程学报, 2022, 44(8): 1453-1462. DOI: 10.11779/CJGE202208010
引用本文: 许彬, 刘新荣, 周小涵, 刘俊, 黄俊辉, 王䶮, 曾夕. 消落带岩体劣化下顺层岩质边坡动力响应规律试验研究[J]. 岩土工程学报, 2022, 44(8): 1453-1462. DOI: 10.11779/CJGE202208010
XU Bin, LIU Xin-rong, ZHOU Xiao-han, LIU Jun, HUANG Jun-hui, WANG Yan, ZENG Xi. Experimental study on dynamic response law of bedding rock slopes under deterioration of rock mass in hydro-fluctuation belt[J]. Chinese Journal of Geotechnical Engineering, 2022, 44(8): 1453-1462. DOI: 10.11779/CJGE202208010
Citation: XU Bin, LIU Xin-rong, ZHOU Xiao-han, LIU Jun, HUANG Jun-hui, WANG Yan, ZENG Xi. Experimental study on dynamic response law of bedding rock slopes under deterioration of rock mass in hydro-fluctuation belt[J]. Chinese Journal of Geotechnical Engineering, 2022, 44(8): 1453-1462. DOI: 10.11779/CJGE202208010

消落带岩体劣化下顺层岩质边坡动力响应规律试验研究

Experimental study on dynamic response law of bedding rock slopes under deterioration of rock mass in hydro-fluctuation belt

  • 摘要: 三峡库区蓄水后导致的消落带岩体劣化和水库诱发地震对岸坡稳定性具有重大影响。采用振动台模型试验探究了消落带岩体劣化下顺层岩质边坡受持续地震荷载作用时的动力响应规律。研究表明:坡体加速度响应具有显著的“高程效应”和“趋表效应”特性,且历经多次地震荷载作用后坡体PGA放大系数衰弱明显,而坡体累积位移、孔隙水压力及土压力随地震荷载持续作用分别呈逐渐增大、增大及减小的变化趋势;坡体阻尼比、自振频率及损伤度随地震荷载持续作用分别呈逐渐增大、减小及增大的变化趋势,且微小地震和强震作用阶段的坡体非线性累积损伤力学模型可分别采用“S”型三次函数和“陡升”型指数函数表征;坡体累积损伤—失稳破坏演化过程表现为坡顶后缘(次级节理和层面)起裂—扩展—贯通、岩体沿复合滑动面整体滑移及完全破坏后岩体呈多尺度破碎块状堆积于坡脚,且消落带岩体受震动、溶蚀及冲刷耦合作用后破碎较严重,并近乎产生整体滑移而形成显著的“凹腔”。

     

    Abstract: The deterioration of rock mass in hydro-fluctuation belt and the reservoir-induced earthquake, which are caused by the impoundment in the area of Three Gorges Reservoir, have a great impact on the stability of the bank slopes. The shaking table model tests are conducted to investigate the cumulative damage mechanism and dynamic stability of bedding rock slopes subjected to continuous seismic loads under the deterioration of rock mass in hydro-fluctuation belt. The results indicate that: (1) The acceleration response of slopes is significantly characterized by "elevation effect" and "surface effect", and the PGA amplification factor weakens obviously after several times of seismic loads. The cumulative displacement, pore water pressure and earth pressure of slopes show the trend of increasing, increasing and decreasing, respectively, with the continuous action of seismic loads. (2) The damping ratio, natural frequency and damage degree of slopes show the trend of increasing, decreasing and increasing gradually, respectively, with the continuous action of seismic loads. The nonlinear cumulative damage mechanical model for slopes under the action of micro-earthquake and strong earthquake can be characterized by "S-typed" cubic function and "steep rise" exponential function, respectively. (3) The evolution process of cumulative damage and instability failure of slopes can be summarized as: the initiation, propagation and penetration of the back edge of slope top (secondary joints and planes), the overall sliding of rock mass along the composite sliding surface, and the accumulation of the multi-scale broken blocks of rock mass at the foot of slopes after complete failure. Moreover, the rock mass in hydro- fluctuation belt is seriously broken by the coupling action of vibration, dissolution and erosion, and nearly slips as a whole to form a significant "cavity".

     

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