【摘要】 为研究路基工程的抗震设计问题,首先对汶川8.0级地震震区路基震害进行调查,发现强震作用下绝大多数未加筋路堤为浅表层边坡坍塌破坏,极少数路堤发生半幅路面错落的本体滑坡现象,所有路堤均未出现沿基础界面的滑动,而土工格栅加筋路堤震害程度轻微得多。根据变形破坏模式,提出以侧向变形控制为核心的土工格栅布筋方案,即在路堤顶部满铺土工格栅、中上部铺设短格栅。利用未加筋路堤和土工格栅加筋路堤大型振动台模型试验进行加筋变形控制方案有效性的对比研究。试验结果表明,路堤顶部满铺土工格栅,阻断竖向裂缝的扩展,从而抑制路堤本体滑坡;护坡道上方铺设短格栅,可有效抑制路堤侧向变形及边坡坍塌。通过对加速度、动土压力测量结果的对比分析,发现土工格栅加筋后,路堤模型的自振频率提高12%,0.7倍坡高处加速度放大系数在中震下减小27%,在大震下减小41%,动土压力幅值也会大幅减小。更多还原

【Abstract】 To study the seismic design of subgrade engineering,subgrade seismic damage of Wenchuan Ms8.0 earthquake was investigated.It was found that most of the un-reinforced embankment suffered from shallow collapse of slope,of which a few were damaged by the sliding of embankment body,but neither of the embankment slid along the embankment-foundation interface.the damage level of geogrid-reinforced embankment was much slighter than that of un-reinforced embankment.Based on the investigation,the geogrid layout scheme was proposed to control the lateral deformation of embankment with long geogrid laid on the top of the embankment,and short geogrid laid on the upper part of the embankment.To validate this layout scheme,the un-reinforced and reinforced embankment were studied comparatively with large-scale shaking table model tests.Results showed that fissure spreading downward was restrained by long geogrid on the top of the embankment,thus deep slide prevented.Lateral deformation and shallow slide of the slope were restrained by short geogrid on the upper part of the embankment.By comparative analysis of acceleration and dynamic earth pressure between those two types of model test,it was found that when the road embankment was reinforced,natural frequency would increase by 12%,magnification factor of acceleration at 0.7 times the height of embankment would decrease by 27% under medium earthquake,decrease by 41% under large earthquake,and dynamic earth pressure would decrease largely also.更多还原