单点冲击荷载在红砂岩填土中的作用效应及强夯加固研究

发布时间：2018-06-17 12:55

本文选题：单点冲击荷载 + 红砂岩土　；参考：《江西理工大学》2013年硕士论文

【摘要】：红砂岩在我国分布广泛,红砂岩土被大量用于回填地基,强夯等冲击荷载加固地基效果显著,但关于强夯等冲击荷载加固红砂岩填土地基方面的研究相对滞后。本文针对红砂岩土,利用改装的击实仪进行室内冲击试验,研究单点冲击荷载在红砂岩土中的作用效应；通过现场强夯试验研究地基加固效果,得到如下主要结论： (1)强夯对红砂岩填土地基的加固作用效应是压缩波的推拉作用、剪切波的剪胀或剪缩作用和瑞利波的翻滚作用的综合结果。 (2)在冲击荷载作用下,红砂岩土粘聚力的增长幅度远大于内摩擦角的增长幅度；红砂·岩土的空间击实效果,坑底土体好于坑周土体,轻锤高落好于重锤低落。 (3)在冲击荷载作用下,夯坑的累计夯沉量随夯击数增加的变化规律可分为增速较快和增速较慢两个阶段；坑底土体以竖向位移为主,坑周土体以水平位移为主；随着单击夯击能的增加(15、20、25、30N·m),使土体产生显著位移的作用范围,在水平方向从3.0～3.5cm变化至6.0～6.5cm,在竖直方向从9.0～10.0cm变化至18.0～19.0cm；随着系统平衡状态程度的不断提高,夯击能用于提高系统平衡状态程度的能量减少,能量利用率降低,系统趋于某个与夯击能对应的相对稳定的平衡状态,不同的夯击能对应着不同的稳定平衡状态。 (4)以本文的强夯施工参数加固红砂岩填土地基效果良好,达到了工程的设计要求。本文的研究成果对丰富强夯等冲击荷载加固地基理论,指导冲击荷载加固地基实践,提高受冲击荷载作用的地基基础设计水平等有较大意义。
[Abstract]:Red sandstone is widely distributed in China, red sandstone soil is widely used in backfill foundation, dynamic compaction and other impact loads to strengthen the foundation effect is remarkable, but the research on strengthening red sandstone fill foundation with impact load such as dynamic compaction is relatively lagging behind. In this paper, the effect of single point impact load on red sandstone soil is studied by indoor impact test with modified compaction instrument, and the effect of foundation reinforcement is studied by field dynamic compaction test. The main conclusions are as follows: (1) the reinforcement effect of dynamic compaction on the red sandstone fill foundation is the push-pull effect of compression wave. The comprehensive result of shear expansion or shearing shrinkage of shear wave and rolling action of Rayleigh wave. Under impact load, the increase of cohesive force of red sandstone soil is much larger than that of internal friction angle. The space compaction effect of red sand rock is that the bottom soil is better than the surrounding soil, and the light hammer falls better than the heavy hammer. The variation law of the cumulative compaction volume with the increase of the number of compaction can be divided into two stages: the vertical displacement in the bottom of the pit and the horizontal displacement in the surrounding soil. With the increase of click-ramming energy, the range of significant displacement of soil changes from 3.0~3.5cm to 6.0cm in horizontal direction and from 9.0~10.0cm to 19.0cmin vertical direction. Tamping can be used to improve the energy reduction of the system equilibrium state, the energy utilization ratio is reduced, and the system tends to a relatively stable equilibrium state corresponding to the tamping energy. Different tamping energy corresponds to different stable equilibrium state. The research results of this paper have great significance for enriching the theory of dynamic compaction and other impact load strengthening foundation, guiding the practice of impact load strengthening foundation and improving the design level of foundation subjected to impact load.
【学位授予单位】：江西理工大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：TU472.31

【共引文献】