极端降雨条件下粗粒土高路堤边坡暂态饱和区时空演变规律及致灾机理研究

项目名称： 极端降雨条件下粗粒土高路堤边坡暂态饱和区时空演变规律及致灾机理研究

项目编号： No.51508042

项目类型： 青年科学基金项目

立项/批准年度： 2016

项目学科： 建筑环境与结构工程学科

项目作者： 何忠明

作者单位： 长沙理工大学

项目金额： 20万元

中文摘要： 建设耐久性路基是降低公路施工全寿命周期成本，提高公路通行能力的战略性举措，符合交通运输“十二五”科技发展规划。极端降雨条件下，粗粒土高路堤边坡将形成暂态饱和区，导致土体强度随时间和空间的变化而发生显著变化，直接影响路堤的耐久性。在高路堤建造时考虑暂态饱和区内土体强度的劣化能显著提高路堤耐久性，而国内外在此方面的研究尚不深入。本项目针对雨季粗粒土高路堤边坡失稳时有发生的现状，首先开展多因素作用下粗粒土渗透特性与土水特征曲线及两者相关性研究；然后基于室内外试验和数值分析，揭示极端降雨条件下粗粒土高路堤边坡暂态饱和区形成条件及其时空演变规律；最后，引入CT损伤变量，建立能描述土体非饱和强度随基质吸力变化及考虑损伤特征的本构模型，结合非饱和抗剪强度理论，探讨暂态饱和区演变影响下边坡安全系数变化规律，揭示考虑暂态饱和区演变影响的边坡失稳机理。研究成果对完善我国耐久性路基建造技术有重要的指导意义。

中文关键词： 粗粒土；；高路堤边坡；暂态饱和区；时空演变规律；致灾机理

英文摘要： Constructing durability roadbed is strategic initiatives to reduce life-cycle costs of road construction and improve road capacity, conform with technological development Twelfth Five-Year Transportation Plan. Under the extreme rainfall, coarse-grained soil high embankment may form transient saturated zone, lead to the strength of soil change significantly over time and space, directly affect the durability of the embankment. Consider with the deterioration of soil strength in the transient saturated zone can significantly improve durability of embankment in the high embankment construction, but the researches in this area is not yet in-depth at home and abroad. This study focus on rainy season coarse-gained soil high embankment instability often occurs, first, launch the study of correlation between coarse gained soil permeability characteristic and soil water characteristic curve (SWCC); and then base on the indoor and outdoor experiments and numerical analysis, reveal the formation condition and spatio-temporal evolution of transient saturated zone of coarse-grained soil high embankment slope under extreme rainfall conditions; Finally, introduced CT damage variable, established the constitutive model which can describe the unsaturated shear strength changed with matric suction and considered the damage characteristic, investigate the evolution of transient saturated zone impact on the slope safety factor variation, reveal the slope instability mechanism considered with transient saturated zone. The research has great guiding significance to perfect the durability roadbed construction technology.

英文关键词： coarse-grained soil;high embankment slope ;the transient saturated zone; the spatio-temporal evolution;the disaster inducing mechanism