考虑土拱效应的挡土墙空间土压力研究

 研究表明土拱效应是影响挡土墙土压力分布的一个重要因素，但目前关于空间条件下考虑土拱效应的挡土墙土压力研究还很少。通过将土拱效应原理引入顾慰慈等建立的空间土压力计算模型建立了考虑土拱效应的空间土压力计算模型，并将该模型划分为I、II、III、IV四个区域，通过在各个区域内取水平微分单元体，建立各微分单元体的水平和竖向静力平衡方程，推导出了各区相应的挡土墙空间主动土压力计算公式，该公式可以计算出墙背任意位置的主动土压力；并提出了空间土压力合力及其合力作用点的计算方法。通过算例计算可以直观的看出挡土墙后主动土压力的空间分布，由此可以看出，当空间效应存在时考虑土拱效应的挡土墙主动土压力沿墙长的分布与平面应变条件时有很大的不同，此时挡土墙两端附近区域的主动土压力远小于平面应变条件下计算出的主动土压力，同时可以看出考虑空间效应的挡土墙主动土压力合力作用点要比平面应变条件下的位置要高，挡土墙长高比B/H越小空间效应对主动土压力沿墙长的分布和主动土压力合力作用点位置的影响越大。

RESEARCH ON SPACE ACTIVE EARTH PRESSURE BEHIND RETAINING WALL CONSIDERING SOIL ARCHING EFFECTS

Research shows that soil arching effects is an important factor that affect earth pressure distribution of retaining wall，but the studies of space active earth pressure behind retaining wall considering soil arching effects is less. Through introducing soil arching effects principle into the space earth pressure calculation model making by Gu Wei-ci，we build the space earth pressure calculation model that considering soil arching effects，then divide the model into I、II、III、IV four regions，and establish horizontal and vertical static equilibrium differential equation of the level differential element that take in each region，and then deduced the calculation formula of space active earth pressure corresponding to each region，it can calculate active earth pressure anywhere behind retaining wall； also put forward the calculation method of resultant force and the position of it’s active point. We can see the distribution of space earth pressure behind retaining wall intuitively through numerical examples，it can be concluded that the existence of spatial effects will make active pressure behind retaining wall considering soil effects quite different from when retaining wall in plane strain state，meanwhile the active earth pressure behind both ends of retaining wall is much smaller than in plane strain state and it can be seen that the place of resultant force point of space active earth pressure is higher than in plane strain state，and the ratio of length and height B/H is smaller，the affect of spatial effects on the distribution of active earth pressure along retaining wall and the place of resultant force point is more.