摘要
针对高填方路堤回填料分层碾压施工中呈现出超固结、剪胀和时间相依等复杂变形特征,以高填方多级挡墙路堤为例,通过现场勘查、室内试验以及变形监测获得回填土石料的力学性质,分别采用摩尔库仑、修正剑桥以及基于下负荷面的弹粘塑性二次开发本构模型,逐步表征路堤回填料的超固结、剪胀以及时间相依变形行为,并结合单元试验以及现场沉降监测数据反演综合确定三种本构模型材料,对比分析三种本构模型模拟高填方路堤施工及工后变形的差异,最后利用有限元强度折减法分析该高填方多级挡墙路堤的稳定性。计算结果表明:在路堤填筑初期(21d),基于下负荷面的弹粘塑性模型和修正剑桥模型相比摩尔库仑模型考虑了先期固结应力,计算沉降量结果稍小;随着施工填筑的进行(100d),一旦超过先期固结应力后,三种模型的沉降量变化逐渐接近;随着时间的增长,仅基于下负荷面的弹粘塑性模型能计算路堤的长期沉降,预测该路堤顶10a工后沉降17cm,满足工后沉降要求;同时发现路堤水平侧移呈“S”型内倾的变化特点,且通过有限元法强度折减计算得到边坡稳定性最小安全系数和最危险滑动面,均满足边坡稳定性要求,路堤边坡的失稳预警位移为4.6cm。
Aiming at the complicated characteristics of embankment fillings such as over-consolidation,dilatancy,and time-dependent deformation under hierarchical compaction,a high-filled embankment with multilevel retaining walls was took as an example to study the mechanical properties of backfill soil by means of site survey,indoor test and deformation monitoring.The Mohrcoulomb model,Modified Cam-clay model and an elastic-viscoplastic constitutive model based on sub-loading yield surface were used in turn to reproduce the over-consolidation,diatancy and time-dependent behaviors of embankment backfill.The parameters of the above three constitutive models were comprehensively determined by data inversion of unit test and field settlement monitoring.Settlement during and after embankment construction obtained from the three models was compared analyzed,and the stability of the embankment was investigated through the finite element strength reduction method.The results show that since the pre-consolidation pressure was taken into account,the settlement calculated through the elastic-viscoplastic constitutive model and the modified Cam-clay model is smaller than that through the Mohr-Coulomb model during the initial stages of construction(21 days).The predicted settlements obtained by the three models are close to each other when the consolidation stress exceeds the pre-consolidation pressure during the process of construction(100 days).However,only the elastic-viscoplastic constitutive model based on sub-loading yield surface can predict the long-term settlement of the embankment,and the simulated post-construction settlement at the embankment surface is 17 cm at the end of the 10 th year after construction,which satisfies the post-construction settlement requirement.A′S′shape is observed in the horizontal displacement curve of the embankment.Both the factor of safety and the critical sliding surface obtained through strength reduction method can well meet the requirements of slope stability.The warning displacement for
作者
王智超
周芊妤
熊赟
胡茜
WANG Zhichao;ZHOU Qianyu;XIONG Yun;HU Qian(Hunan Key Laboratory of Geomechanics and Engineering Safety,Xiangtan University,Xiangtan 411105,China;College of Civil Engineering and Mechanics,Xiangtan University,Xiangtan 411105,China;Hunan Provincial Key Laboratory of Geotechnical Engineering for Stability Control and Health Monitoring, Hunan University of Science and Technology,Xiangtan 411201,China)
出处
《防灾减灾工程学报》
CSCD
北大核心
2018年第6期980-988,共9页
Journal of Disaster Prevention and Mitigation Engineering
基金
国家自然科学基金项目(51308485)
湖南省自然科学基金项目(2016JJ2133)
湖南省教育厅优秀青年项目(17B260)资助
关键词
多级挡墙路堤
超固结
弹粘塑性
沉降变形
稳定性
high-filled embankment with multilevel retaining walls
over consolidation
elasticviscoplasticity
settlment
stability
