环形沉井刃脚斜侧面基础地基极限承载力分析

Analysis of ultimate bearing capacity of ring cutting curbs on open caisson foundation bevels

首先探究了沉井下沉时刃脚踏面下土体的滑移方向,并以此为基础,基于Mohr-Coulomb准则,利用更有利迭代收敛的有限差分公式将滑移线理论的α和β两族特征线方程进行差分并建立刃脚斜侧面承载力数值计算模型;然后根据刃脚侧斜面边界条件,利用Matlab软件编制计算程序对下沉过程中环形沉井刃脚斜侧面基础的地基极限承载力进行了分析,得出了环形沉井刃脚斜侧面土压力分布特性和变化规律;同时对不同的参数c,,γ,堆载及结构尺寸等因素进行极限承载力分析.结合工程实例,把该理论计算结果和现场实测结果进行对比分析,研究结果表明:使用滑移线理论计算刃脚斜侧面的地基承载力方法,对于沉井结构设计及类似工程能取得良好效果.

The direction of soil slip under the cutting curb was analyzed.On the basis of Mohr-Coulomb principle,the more iterative convergence finite difference method was applied to discrete the α,β two family characteristics equation deduced from the slip line theory.A numerical model for the bearing capacity of cutting curb bevel was built.According to the cutting curb bevel boundary conditions,the ground ultimate bearing capacity was analyzed through Matlab software program and the soil pressure distribution characteristics and change law of cutting curb bevel foundation were obtained.At the same time,the ultimate bearing capacity was studied while different influencing factors,including c,,γ,loading,structure size,and the edge foundation roughness were adapted.The results show that the calculational method of ultimate bearing capacity about catting curb bevel foundation which deduced from the slip line theory was of grat significance with ragard to the open caisson structural design and similar projects.