红砂岩路基强夯处理大变形数值模拟方法与效果分析

Large-strain numerical simulation and experimental result reseach about improving red-sandstone embankment by dynamic compaction

针对红砂岩路基难以压实的特性,采用强夯方法,提高红砂岩路基压实度。基于强夯处理红砂岩路基的现场试验,采用显示动力有限元程序LS-DYNA建立强夯三维模型,对强夯的动力响应进行了数值模拟,研究了强夯作用下红砂岩碎石土路堤的应力-应变变化规律,得到了强夯后土体的应力场、位移场,并与现场试验结果进行了对比,分析了强夯加固红砂岩路基的作用机制及有关夯击参数的取值方法,认为直径为2 m的夯锤在1 200 kN.m夯击能作用下的有效影响深度为4～6 m,锤间距(中心距)不宜大于3.5 m。

Since the uncompressible for red-sandstone embankment, the dynamiic compaction method is used and the 3D FEM model about improving red-sandstone embankment by dynamic compaction is established. The numerical simulation of whole dynamic compaction process is carried out; and the coutours of displacement ＆ stress are obtained with explicit dynamic finite element program ANSYS/LS-DYDA. The results show that the orderliness of stress ＆ strain is quite consistant with the experimental results. The mechanism of improving red-sandstone embankment via dynamic compaction as well as how to determine compaction parameters is also analyzed.Meanwhile,the results show that the effective influence depth is about 4-6 m, and the hammer＇s contact distance is about 3.5 m, for hammers with tamping-energy is 1 200 kN · m and diameter is 2 m.