强夯法加固高路堤的试验与研究

【作者】 何长明；

【导师】 李亮；

【作者基本信息】 中南大学 ， 道路与铁道工程， 2006， 硕士

【摘要】 强夯法加固地基具有工艺简单、效果明显、施工设备少、费用低、质量控制容易、适用范围广、施工周期短等优点。常吉高速公路为红砂岩高路堤，由于土石混填路基在施工中存在压实度控制困难、施工质量难以保证的特点，这就导致高填土路基的工后沉降大且持续时间长，不利于甚至威胁到行车安全，故设计采用强夯法补强加固高填方路基。为取得强夯加固红砂岩路基的施工参数及加固效果，以优化强夯的施工设计，做了大型的强夯补强加固高填土路基的现场试验。基于上述问题开展了试验研究，开展了大型的现场试验，通过在不同位置处埋设沉降板，得到了不同夯击能下土体周边变形、土体沉降及不同深度处的沉降关系，建立强夯理论模型，分析了夯沉量与孔隙率和压实度的关系；通过在土中不同位置埋设土压力盒，用动态应变仪记录下不同夯击能量下动应力的曲线，分析了动应力的传播与衰减规律，以及连续夯击时动应力的变化；绘制了动应力等值线图，从等值线图上分析了压缩波、剪切波和瑞雷波的作用范围和强夯加固地基的深度和宽度；最后对强夯加固地基的效果用平板载荷试验和密度探坑试验进行了检验，结果显示强夯法加固高填土路堤效果明显。结合该试验和其他工程实例，根据量纲的协调性原则，推导出了强夯加固地基有效深度的计算公式，并根据泊松比的定义，提出了强夯加固地基有效范围的经验公式，为今后强夯施工的设计提供了参考依据。更多还原

【Abstract】 Dynamic compaction is a method for foundation reinforced, which have the simple craft, the remarkable effect, less construction equipment, low expense, easily controlled quality, extensive application, short construction cycle and so on the merits.Changde-Jishou expressway is of red-sandstone high foundation, because the soil-stone filled foundation is hard to control the compactness and to guarantee the construction quality, which caused the large settlement of the high embankment and the duration to be long and disadvantage for traffic safety. Therefore designs use the dynamic compaction to make up the strong reinforcement to fill the foundation. In order to obtain the construction parameter and the reinforcement effect of the dynamic compaction reinforced red sandstone foundation, large-scale field test that is compaction reinforcing the high earth filled foundation was carried out by optimized compaction design.The large-scale field test has been performed in the experimented road section based on the above question. The soil peripheral deformation, the soil settlement and the different depth settlement have been obtained with different compaction strikes energy through embedding ground the settlement board in the different position. The dynamic compaction theoretical model has been established for analyzing the relations between compaction settlement and compaction degree. Through embedding ground the soil pressure cell in different earth position, recording the dynamic stress-time curve under different compaction strikes with the dynamic strain gauge, the dynamic stress spread and attenuation rule, as well as the dynamic stress change under the continuous compaction strikes had been analyzed. Contours of dynamic stress had been drawn up and the effective range, the depth and length of dynamic compaction caused by P-wave, S-wave and R-wave were analyzed from these contours. Finally the reinforcement effect of compaction on the foundation was carried out on the examination with the plane loading test and density test, the result demonstrated that the effect of reinforcing high embankment by dynamic compaction is obvious.Combine the experiment with other engineering examples, the formula that determines the effective depth of consolidation was deduced with dimensions analysis. The experience formula of reinforcement range was established based on the definition of Bossion ratio. All of these afford reference for design of compaction construction.更多还原