基础工程学土拱与土楔效应精品课件.pptx

1、课程团队：徐长节、胡文韬、耿大新、可文海、陈丹华基础工程学华东交通大学土木建筑学院7 土与基础相互作用 7.4 土拱与土楔效应n主讲人胡文韬1948年法国的拱效应发现Feld 1948“筒仓理论”示意图土拱效应在土力学中的发展nTerzaghi 1943If one part of the support of a mass of soil yield while the remainder stays in place the soil adjoining the yielding part moves out of its original position between adjacen

2、t stationary masses of soil.The relative movement within the soil is opposed by a shearing resistance reduces the pressure on the yielding part of the support and increases the pressure on the adjoining stationary part.This transfer of pressure from a yielding mass of soil onto adjoining stationary

3、parts is commonly called the arching effect.土拱的形状描述n拱形方程拱效应在工程中的存在“拱结构”不等于“拱效应”水平土拱土拱存在的条件p土体颗粒间具有足够的黏结力与摩擦力p存在支撑拱脚的条件p土体内部产生不均匀位移或相对位移n Norris（1977）土楔模型n主要参数p底角mp深度Hp伞角mp水平应力增量hp桩侧的剪应力楔模型的几何参数nAshour 1998p桩身位移沿深度呈线性变化p应变楔内土体的应力条件试验可获得应变楔模型基本假设条件n朗肯/库仑土压力适用情况p平面应变模型p变形同步发生n结构非连续/变形异步情况土拱/土楔效应的思考朗肯/库仑群桩土楔效应群桩水平弹簧系数本章小结n土拱效应n土楔效应