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采用大尺寸原状黄土与重塑黄土联合制作模型,针对Q2、Q3黄土深堑中超高填方地基在天然含水率及饱和状态时的沉降变形规律开展大型离心模型试验研究,系统模拟了超高黄土填方地基在施工期及工后期的变形规律。结果表明:此类高填方地基的施工期沉降变形是总变形量主要组成部分;地基填筑完毕后表面沉槽轮廓清晰,填筑过程中沉降速率随施工填方高度增加而增大,沉降变形中部大、两侧小,且填方体与原地基结合部位的变形缓坡较陡坡一侧小;天然状态下的地基整体沉降变形较小,差异变形量较大,饱和状态下的地基沉降变形增大,差异变形量较小,稳定性较差,差异变形使得原地基与填方体极易发生错动开裂。根据模型试验的分析规律,建议此类地基施工过程中宜对填方体与原地基接触带进行处理,以改善填方体约束条件,同时,填筑完工前可预留一定高度,待前期变形基本完成后,再施工至设计标高,以防止过大差异变形导致的工后开裂。
Large-scale loess and remolded loess were used to make the model. Large-scale centrifugal model tests were carried out to study the settlement and deformation of super-high filling foundation in Q2 and Q3 loess with natural moisture content and saturated condition. Deformation regularity of filling foundation during construction and in later period. The results show that the settlement deformation of such high-fill foundation during construction is the main component of the total deformation. After the foundation is filled, the outline of the surface sinking is clear. The settlement rate increases with the height of the construction fill during the filling process, The deformation of the middle of the large, small on both sides, and the deformation of the fill body and the original site of gentle slope than the steep slope side of small; natural state of the whole foundation settlement less deformation, large deformation, saturated settlement Increase, the difference of deformation is small, the stability is poor, the difference deformation makes the original ground and fill the body prone to staggered cracking. According to the analysis of the model test, it is suggested that the contact zone between the filling body and the original ground should be treated during the construction of such foundation so as to improve the constraints of the filling body. At the same time, a certain height can be reserved before the completion of filling, After the basic completion, construction to design elevation, to prevent excessive deformation caused by the post-construction cracking.