斜坡震裂变形力学机制初探

为了深入分析斜坡在地震中的震裂变形破坏形成机制,结合5.12汶川大地震造成的斜坡震裂变形和破坏现象的详细调查,采用有限元数值分析和振动台模拟实验相结合的研究方法,对单面和双面斜坡震裂变形的力学机制进行初步分析,认为地震中地震波的作用,将使坡体应力场出现重大变化,坡体尤其是坡面上将出现量值和方向不断调整变化的反复拉剪作用,是坡体(面)震裂变形甚至破坏的重要原因。分析还认为,拉剪作用有3种表现形式,即初动拉剪加速破裂效应、重复拉剪破坏效应和双坡共剪破裂效应,并结合实例对3种破坏效应进行分析。研究成果为预测震裂斜坡破坏提供了有力参考,也为灾后重建和防灾减灾提供了有力依据。

探地雷达在斜坡震裂变形探测中的应用研究

5.12汶川大地震造成了大量山体震裂变形,形成了众多次生潜在灾害。这类震裂变形的深部特征是控制斜坡稳定性和发展演化规律的关键。本文以探地雷达为主要手段,结合探槽开挖验证对比,选择实例震裂边坡,对震裂变形的深部特征及探地雷达图像显示特点进行了研究。研究结果认为,斜坡震裂变形破坏深度一般不超过2m,裂缝近垂直向下发育,少数微倾坡外,探地雷达反射图像显示为双曲线特征,总体构成封口状"八"字形。研究成果为快速、有效探测震裂裂缝,尤其是垂向裂缝的深部扩展特征提供了有效参考方法,同时也为防灾减灾提供了技术支撑。

地震波效应与山体斜坡震裂机理深入分析

"5·12"汶川大地震造成了大量山体斜坡震裂变形和破坏现象,为深入研究其力学机理,通过实例详细调查及地震中体波效应和面波效应的深入分析,认为地震中地震波的作用使山体斜坡表部岩土体尤其是坡肩部位受到量值和方向不断变化的拉张应力作用,该作用在垂直平面内表现为全方位动态变化特点,导致坡肩岩土体具有旋转倾倒和正、反拉作用;与此同时在坡体内部伴随出现潜在剪动作用力及岩土体的开裂和压碎现象,尤其在潜在滑动面上剪切作用力更为集中;此外坡体表面还受到鼓胀拉力和扭力的共同作用。据此可将地震波作用效应划分为4种重要表现形式,即拉-剪破裂效应、界面动应力效应、潜在的楔劈效应和超空(孔)隙水压力激发机制。分析结果与实例及振动模拟结果一致。研究成果可为灾后重建和防灾减灾提供参考。

Relationship between the rock mass deformation and places of occurrence of seismological events

Static effort of rock mass very rarely causes of rock burst in polish coal mines. Rock bursts with source in the seismic tremor within the roof rock layers are prevailing. A seismic tremor is an effect of rupture or sliding in roof layers above the exploited panel in coal seam, sometime in a distance from actual exploitation. Sliding, as a rule occurs in fault zone and tremors in it are expected, but monolithic layer rupture is very hard to predict. In a past few years a practice of analyzing state of deformation in high energy seismic tremors zones has been employed. It let gathering experience thanks to witch determination of dangerous shape of reformatted roof is possible. In the paper some typical forms of roof rocks deformations leading to seismic tremor occurrence will be presented. In general these are various types of multidirectional rock layers bending. Real examples of seismic events and rock bursts will be shown.