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基于二维颗粒流软件(PFC2D)的人工合成岩体技术,研究岩桥长度和节理间距不同组合形式下的含水平断续节理厚层状岩质边坡在地震作用下的破坏模式、动力响应规律以及岩桥段应力演化特征。研究结果显示:地震动作用下,含水平断续节理厚层状岩质边坡主要发生溃散型破坏、拉裂–滑移–块体倾倒混合破坏和拉裂–水平滑移混合破坏;水平断续节理是控制边坡动力稳定性的关键因素。节理间距对边坡破坏模式起控制性作用:当节理间距较小时,易发生溃散型破坏;当节理间距较大时,易发生拉裂–滑移–块体倾倒破坏和拉裂–水平滑移混合破坏。岩桥长度和节理间距共同控制着边坡岩体破碎程度,从而控制着边坡失稳破坏时滑动面的个数,当节理间距很小或者节理间距较大、岩桥长度较小时,发生单滑动面破坏;当节理间距和岩桥长度均较大时,发生双滑动面破坏。在地震动力作用下,岩桥段首先发生破坏,随后各节理间也产生破坏并贯通。岩桥长度和节理间距对边坡动力响应均产生一定影响,随着节理间距减小、岩桥长度增大,峰值位移、峰值速度增大,对加速度PGA放大系数的影响区域集中在边坡坡表、坡脚等部位。地震作用下,含水平断续节理厚层状岩质边坡岩桥段应力演化、裂纹萌生与输入的地震波加速度具有良好的一致性。
Based on the artificially synthesized rock mass technology of two-dimensional particle flow software (PFC2D), the failure modes and dynamic responses of thick-layered rock slopes with horizontal discontinuous joints subjected to earthquake under different combinations of rock bridge length and joint spacing are studied. Regularity and stress evolution of rock mass. The results show that under the earthquake action, the thick discontinuous jointed rock slope with horizontal fractured joints are mainly collapsible-type failure, pull-slip-block-dumping mixed failure and pull-fracture-horizontal slip mixed failure; Continued joints are the key factors controlling the dynamic stability of slopes. The joint spacing plays a controlling role in the failure mode of the slope: when the joint spacing is small, it is prone to collapsing failure; when the joint spacing is large, the splitting-sliding-block collapse and the fracture-horizontal slide Mixed destruction. Rock bridge length and joint spacing jointly control the degree of slope rock mass crushing, so as to control the number of sliding surface when the slope failure instability damage. When the joint spacing is small or joint spacing larger, rock bridge length is small, the single Sliding surface damage; when the joint spacing and rock bridge length are larger, the occurrence of double sliding surface damage. Under the action of earthquake power, the rock bridge section first destructed, and then the joints also broke and penetrated. The influence of rock bridge length and joint spacing on slope dynamic response are all affected. As the joint spacing decreases, the length of rock bridge increases, the peak displacement and peak velocity increase. The influence area of acceleration PGA magnification is concentrated on the slope Table, slope foot and other parts. Under earthquake action, the stress evolution, crack initiation and seismic acceleration of input thick-bedded rock slope with good consistency are in good agreement.