标题: 回填土密度对被动土压力之影响
Passive Earth Pressure with Various Backfill Densities
作者: 李纪经
Lee, Chi-Ching
方永寿
Fang, Yung-Show
土木工程学系
关键字: 回填土密度;垂直挡土墙被动土压力
公开日期: 1997
摘要: 本论文探讨回填土密度对作用于垂直挡土墙被动土压力之影响。模型试验采用 31%,60%,与84%相对密度之渥太华砂为回填材料。本研究利用国立交通大学模型档土墙设备研讨由于平移模式墙位移所造成土压力之变化。根据实验结果,得到以下各项结论。当被动墙位移量达到0.14H(H=墙高)时,被动土压力就达到一定值,无论其初始状态为疏松或紧密。这是因土体内之破坏面上已大量剪力变形,达成一“临界状态”(Critical State)。两种类型之土压力可视为被动状态。一者以“尖峰”被动土压合力定义,另一者以大量墙位移引致“临界状态”被动土压合力定义。实验结果显示,传统库仑与德在基理论明显高估了被动土压力。然而,若将由直接剪力实验中所得到之临界状况下之内摩擦角鹩r与墙摩擦角踄r 带入Coulomb公式中,理论值与实验值吻合良好。大地工程师于设计档土墙时,必须将临界状态之观念加入被动土压力之计算。
This paper presents experimental data of earth pressure acting against a veritical wall, which moved toward a mass of dry sand with different densities. Backfills with relative density of 31%, 60%, and 84% are tested. The instrumented retaining-wall facility at National Chiao Tung University was used to investigate the variation of earth pressure induced by the translational wall movement. Based on this study, the following conclusions can be drawn. As the passive wall movement S/H exceeds 0.14, the passive soil thrust reaches a constant value regardless of the initial density of the backfill. This is because at this state the soil along the failure surface has deformed significantly and reached the "critical state". Two types of earth pressure can be defined as passive. One group is defined by the peak passive thrust, and the other group is defined by the critical passive thrust. Experimental results indicate that both Coulomb and Terzaghi theories overestimated the passive soil thrust. However, if the □ and □ angles obtained from direct shear tests at its critical state are used in the Coulomb and Terzaghi solution. The theoretical solutions are found to be in very good agreement with the experimental data. It is important that the concept of critical state should be included by geotechnical engineers during the design of retaining structures.
URI: http://140.113.39.130/cdrfb3/record/nctu/#NT863015023
http://hdl.handle.net/11536/63267
显示于类别:Thesis