摘要
根据交通荷载的特性和重复荷载下土体的变形特征,对土体在交通荷载作用下的弹塑性模型做了改进,利用FLAC3D软件分析了交通荷载下稳定粉土路基的动力响应,研究了土体参数对路基变形的影响和交通荷载作用下路基的变形规律。分析结果表明:交通荷载具有动力性、反复性,可将其简化为不连续的半正弦动力荷载;土体在循环荷载的反复作用下塑性变形将逐渐积累,随循环次数增加,初始屈服面不断增大,最后逼近于最大加载面;在单次半正弦荷载作用下,荷载作用点的位移最大,土体的最大位移和残余位移都随土体的阻尼参数、弹性模量、粘聚力和内摩擦角的增加而减小;在重复荷载作用下,土体变形在荷载作用初期变化较大,随着荷载循环作用次数的增加,变形增加的速率逐渐减小。该研究对于粉土地区的高速公路建设具有重要的理论意义和实际价值。
Based on the fundamental features of traffic loading,a new modified elasto-plastic model is proposed to describe the deforming characteristics of soils under cyclic loading.A program is compiled through FISH language of FLAC3D,and is used to calculate the dynamic responses of stabilized silt subgrade under traffic loading and the effects of soil parameters on the deformation of subgrade are discussed.The rule of silt subgrade deformation under traffic loads is also analysed in this article.The traffic load has dynamic and repitition characteristics so they are simplified to a discontinuous semi - sinusoidal dynamic load. Soil ＇ s plastic deformation will gradually be accumulated for the repeated load, the initial yielding surface increased to the maximum load surface ; Under single half sine loading, the stress is maximal at the loading point, the maximal displacement and unrecoverable displacement increased with the decrease of damping parameters, elastic modulus, cohesion, inner friction angle ; Under cyclic loading, the de- formation is obvious during the early cycles of loading. With the loading number increasing, the growing rate of soil deformation decreases. The results have important theoretical and practical meanings for highway engineering.
出处
《地下空间与工程学报》
CSCD
北大核心
2009年第5期1013-1019,共7页
Chinese Journal of Underground Space and Engineering
基金
国家自然科学基金(40872173)
关键词
粉土
路基
交通荷载
动力响应
silt
subgrade
traffic loading
dynamic response
