深基坑悬臂式围护结构地震响应分析
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摘要
悬臂式围护结构是深基坑最常采用的围护结构形式。应用有限单元法分析了深基坑悬臂式围护结构在地震波作用下的响应。计算结果表明,地震作用下悬臂式围护结构的弯矩出现波动,当地震强度较低时,其分布特征变化不大,但在强度较高地震作用下,上部结构的弯矩值显著增大。在地震波作用下,基坑内侧土体的塑性区明显向下发展,而上部的塑性区则朝着背向基坑的方向发展。基坑深度相同时,悬臂式围护结构的入土深度越大,结构本身受地震的不利影响越大,围护结构与土体的接触压力受地震影响的程度也增加,但此时地震荷载对土体塑性区的影响降低,对场地抗震稳定性有利。
Cantilever retaining structure is commonly used in deep foundation pit engineering,and its seismic response is studied by FEM.The calculation results show that the bending moment of cantilever retaining structure fluctuates under earthquake;for low-intensity earthquake,the distribution features don't change,but in a high-intensity earthquake,the bending moment of upper structure increases significantly.Under seismic load,plastic zone of the soil inside the foundation pit develops downward,and the plastic zone of upper part develops backward away from the foundation pit.When the pit depth is the same,the greater the embedded depth of the cantilever retaining structure is,the larger adverse impact the structure undertakes,and the influence of earthquake on contact stress between the soil and retaining structure increases,but the influence on plastic zone decreases,which is favorable to anti-seismic stability of the foundation pit.
Cantilever retaining structure is commonly used in deep foundation pit engineering,and its seismic response is studied by FEM.The calculation results show that the bending moment of cantilever retaining structure fluctuates under earthquake;for low-intensity earthquake,the distribution features don't change,but in a high-intensity earthquake,the bending moment of upper structure increases significantly.Under seismic load,plastic zone of the soil inside the foundation pit develops downward,and the plastic zone of upper part develops backward away from the foundation pit.When the pit depth is the same,the greater the embedded depth of the cantilever retaining structure is,the larger adverse impact the structure undertakes,and the influence of earthquake on contact stress between the soil and retaining structure increases,but the influence on plastic zone decreases,which is favorable to anti-seismic stability of the foundation pit.
引文
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