土体中应力分布基本规律的探讨

Discussion on Basic Law of Stress Distribution in Soil

摘要:

基于土体的颗粒结构和只有颗粒接触传递应力的特性，对不同姿态颗粒接触中应力传递的机理分析，揭示了土体在相对静态下存在主动力的应力扩散效应和强被动力的应力集中效应，及其形成的土体中应力分布基本规律。主动力的应力场是以其所在土层的应力扩散角θ向外扩散的园锥形应力范围，在应力场内应力扩散分布，主应力方向不变，且伴有与之垂直的法向应力，应力分布均衡了应力场内颗粒和支承面的位移趋势。强被动力的支承面上存在以θ角向外扩散倒锥台形的应力平衡范围，在此范围内反向应力集中作用到强支承面，强支承面主导了其所在应力场的应力分布。土拱效应是应力集中效应的衍生效应，是相邻的同向强支承反力的应力平衡范围发生重迭时产生的现象。

Abstract:

Based on the particle structure of soil and the characteristics of stress transfer only by particle contact, the mechanisms of stress transfer in the different attitudes of particle contact are analyzed. The stress dispersion effect of the main force and the stress concentration effect of strong driven force existing in the soil under the static state are revealed as well as the basic law of stress distribution in its formed soil. The stress field of the main force is a conical stress range that diffuses outward at a stress diffusion angle θ of the soil layer in which it is located. The stress diffusion and distribution is in the stress field. The main stress direction does not change and is accompanied with normal stress perpendicular to it. The stress distribution equalizes the particles in the stress field and the displacement trend of bearing surface. There is a stress equilibrium range of the inverted cone-shaped platform which diffuses outward at an angle θ on the bearing surface of strong driven force. In this range, the reversal stress is concentrated on the strong bearing surface. The strong bearing surface dominates the stress distribution of the stress field in which it is located. The soil arch effect is a derivative effect of the stress concentration effect, and is a phenomenon occurring when the stress balance range of adjacent strong bearing reaction overlaps.