鄂尔多斯丘陵区砒砂岩风—冻融复合侵蚀力学机理研究

项目名称： 鄂尔多斯丘陵区砒砂岩风—冻融复合侵蚀力学机理研究

项目编号： No.41261070

项目类型： 地区科学基金项目

立项/批准年度： 2013

项目学科： 天文学、地球科学

项目作者： 李晓丽

作者单位： 内蒙古农业大学

项目金额： 50万元

中文摘要： 鄂尔多斯高原地形破碎，植被稀少。地表多为砒砂岩土壤-栗钙土，这种土壤结构差，稳定性较低，抗蚀性弱，水土流失严重。本项目针对该地区砒砂岩特殊的理化性质及冬春季昼夜温差悬殊的气候特点，通过野外试验及室内冻融试验，寻找冻、融温度、循环次数与土性指标、胶结强度、抗剪强度的关系，建立边缘砒砂岩土体在纵剖面及横剖面上应力状态改变与温度变化的关系，研究砒砂岩土体冻融主要机制；通过风洞试验，研究风速变化对土体剥蚀厚度、剥蚀速率的影响，建立风速变化引起不同下垫面土体受力的半经验关系模型。以得到的应力状态改变与温度变化的关系为基础，应用空气动力学、粘弹性流体力学等基础理论，研究反复冻融后，土体在变化的内应力、风力、重力共同作用下，引起的土体位移及平衡破坏机理，建立风-冻融复合侵蚀下，土体临界平衡破坏的力学方程，从微观层次上分析砒砂岩土体剪切带发生剥蚀过程。

中文关键词： 砒砂岩；力学性能；本构模型；冻融循环；风-冻融侵蚀

英文摘要： In the Ordos plateau region,terrain is broken and vegetation is scarce.Surface is mostly soft rock-chestnut soil.The chestnut soil is poor structure,low stability,weak corrosion resistance,serious soil and water loss.According to special physical and chemical property of the soft rock and climatic characteristics of the sharp temperature differences between day and night in winter and spring,the research project finds its relationship with frozen and melt temperature,cycle times,the local index,cementation strength,shear strength,establishs its relationship with variation of stress state and temperature on the longitudinal profile and cross section of marginal soft rock soil,and researchs freeze-thaw main mechanism by field test and indoor soil freeze-thaw test; By wind tunnel test the project researchs the effect of velocity changes on erosion thickness of soil and erosion rate, establishs the semi-experience model of different underlying surface soil force causined by velocity changes.At last the project researchs soil displacement caused by the action of internal stress,wind and gravity for variation of soil based on its relationship with Variation of stress state and temperature after repeated freeze-thaw with the fundamental theory of aerodynamics and viscoelasticity hydrodynamics,establishs the mechanics e

英文关键词： pisha-sandstone；mechanical property；constitutive model；reezing and thawing cycles；wind erosion and freeze-thaw erosion