切方边坡悬臂桩桩间土稳定性研究

在调查分析切方边坡悬臂桩桩间土破坏模式的基础上，指出在桩间净距不大的情况下，桩间土多表现为局部滑塌现象。通过分析斜坡切方前的初始应力状态及桩间土滑塌失稳的临界判据，结合岩土强度理论建立了考虑三维土拱效应及切方卸荷的桩间土稳定性分析模型。以襄－渝二线施工过程中某路堑边坡为研究对象，通过计算分析，结合现场施工的观测情况，指出桩间土滑塌曲面的后缘线一般位于桩顶土拱作用的拱圈内侧区域，桩间土多呈拉-剪破坏模式。工程实践表明，采用土钉对桩间土进行加固取得了良好的效果。数值模拟发现，土钉的钻进应穿越桩间土拱有效作用的区域，土颗粒的楔紧挤密效应在一定程度上对土钉起到等效锚固的作用。

Study of stability of soil between adjacent cantilever piles in incised slope

The soil mass may appear partial sliding failure under shorter clear-space circumstance, which is based on survey and analysis of cantilever piles in incised slope. Three-dimensional soil arching effect and cutting-unloading stability analysis model of soil between adjacent piles is established based on the geotechnical strength theory and analysis results about initial stress and criterion of sliding failure. An incised slope of Xiang-Yu-Ⅱ Railway project is researched based on its theoretical calculation and field engineering observation. It is indicated that trailing line on sliding curved of soil between piles is usually located just inner side of soil arching effect; the soil appears sliding trend because of tensile-shear yield failure. It is also proved by practical engineering that soil nails accepted to bracing soil mass between piles can produce preferable reinforcement benefit. The soil nails should be drilled into area of soil arching, which is based on results of numerical simulation. Wedge-compact processes from soil grains bring some anchoring effect by a certain extent to soil nails.