某卸荷拉裂岸坡发展趋势三维有限元分析

Three-Dimension FEA of Stress Evolvement and Development Trend on Bank Slope with Relaxed-Tension Crack

在简述某典型卸荷拉裂岸坡基本地质特征及卸荷拉裂特征的基础上,通过三维有限元数值模拟,分析了拉裂缝形成前、后岸坡的应力状态,以及库区正常蓄水后岸坡应力场的发展趋势。数值模拟计算结果表明:岸坡拉裂缝的产生,是特殊地质条件下岸坡长期卸荷的结果;拉裂缝的产生,使岸坡应力场发生了变化,促使拉裂进一步扩展,但目前拉裂缝发展的深度,不致引起岸坡岩体发生贯通至坡面的剪切破坏;库区正常蓄水后,岸坡应力场进一步发生变化,促使拉裂缝进一步向下、向上发展,但向外发展的趋势减小。如对深拉裂缝进行合理有效的处治,在工程期内岸坡不会发生沿拉裂缝的整体剪切破坏。

Based on the introduction of basic geological characteristics and relaxed-tension crack feature of a typical bank slope with relaxed-tension crack, the state and trend of bank slope stress are analyzed before and after tension crack formation as well as after water storage of the reservoir. The results of numerical calculation show, that the formation of bank slope tension crack is the result of long-term unloading of bank slope under special geological condition. The emergence of tension crack changed bank slope' s stress field and impelled further expansion of the tension. But the depth of tension crack at present wouldn' t cause the bank slope rock mass to shear failure through to slope surface. After normalized water storage of the reservoir, the bank slope's stress field changed farther and impelled the tension crack expanding further up and down, but the outward development trend was weakened. Under the condition of rational and effective treatment of deep tension crack, the whole shear failure along deep tension crack in the bank slope could not take place.