含膨胀性细粒碎屑堆积体开挖稳定性数值模拟  

Numerical Modeling of Excavation Stability of Debris Accumulation Body with Expansive Fine Grain

作　　者：郑立宁[1,2] 谢强[2] 胡启军[2] 赵文[2] 陈云 高岩川 

机构地区：[1]中国建筑西南勘察设计研究院有限公司,四川成都610081 [2]西南交通大学土木工程学院,四川成都610031

出　　处：《铁道学报》2012年第11期83-87,共5页Journal of the China Railway Society

基　　金：中建股份研发课题(CSCEC-2008-Z-30-4)

摘　　要：为探讨膨胀性细粒对碎屑堆积体开挖稳定性的影响机理,利用颗粒流方法,基于室内试验,将细粒膨胀性效应分解为细粒强度衰减与体积膨胀,并以地表向下线性递减方式作用于堆积体。模拟结果与传统有限元对比分析表明:颗粒流分析方法能够模拟膨胀土的多裂隙结构及其受降雨影响下的强度与体积变化特征,模拟结果更准确真实。计算结果表明:考虑膨胀作用时,使堆积体破坏模式由局部塌滑转化为表层滑动,堆积体内部水平方向应力增加20kPa左右,整体下滑力增加30%左右。目前现场开挖中堆积体破坏模式基本符合计算结论,建议加紧雨季施工。To study the influence mechanism of expansive fine grains on excavation stability of the debris accumulation body,by utilizing the Particle Flow Code and resorting to the indoor laboratory tests,the fine-grain expansive effect was disintegrated into the fine-grain strength attenuation and volume expansion,and decreased linearly and progressively from the ground surface down to the accumulation body.Comparing the simulated results of the Particle Flow Code with the traditional finite element method,it is seen that with the Particle Flow Code the fissured structure of expansive soil and its variation characteristics of strength and volume under the influence of rainfall can be simulated with more accurate and true results.Calculations show that when taking into consideration the expansion action,the damage mode of the accumulation body is changed from partial slump to surface sliding,the interior X-direction stress is added by about 20 kPa and the sliding force of the whole accumulation body is added by 30% more or less.The present damage mode of the debris accumulation body in field excavation is basically consistent with the calculation results.So it is suggested that construction should be speeded up during the rainy season.

关 键 词：膨胀性 碎屑堆积体 稳定性 颗粒流 

分 类 号：U213.1[交通运输工程—道路与铁道工程]