深厚软土地基上振动沉入钢护筒机理研究

Study on Mechanism of Steel Tube Drived by Vibration Method in Deep Soft Soil Foundation

利用三维有限差分法进行数值计算并结合现场实测资料,研究在深厚软土地基上振动沉入钢护筒过程对周围土层的挤压效应,分析挤压应力和超孔隙水压力随时间的发展变化过程以及对地表沉降的影响。数值计算给出不同的钢护筒沉入深度、离开钢护筒不同的径向距离以及沿不同的地层深度的孔隙水压力分布特征。此外,还将数值计算结果与现场实测资料进行了比较。研究表明,振动过程中孔隙水压力的发展过程可以分为三个阶段,即急剧增长阶段、缓慢增长阶段及平稳变化阶段;振动过程中孔隙水压力随着沉入深度的增加而向深处推进。

Using numerical calculation results and measured data in-situ, the disturbance effects caused by the steel tube drived in deep soft soil foundation by vibration are studied, and the development and change of the extruding pressure, pore water pressure and ground surface settlement with time are analyzed. Considering the depths of steel tube driving, some typical numerical results are given, which show the distribution characteristics of pore water pressure along the different depth of soil layer at different radial distance. The numerical results are also compared with field test results, which show a good accordance. The studies show that the development processes of pore water pressure can be considered as three stages, namely rapidly increasing stage, continually developing stage and steady stage. Besides, it can be observed that the pore water pressure increases with driving depth increasing in the process of vibration.