膨胀土地基扩底桩上拔承载力数值模拟

Numerical Simulation of Uplifting Bearing Capacity of Expanded Belled Piles

膨胀土的问题越来越被工程界所重视,尤其是我国有大量的建在膨胀土上的输电线路抗拔基础。利用已有的关于中等膨胀土的实验数据,采用弹性模量折减的方法,同时考虑了膨胀土含水率升高造成的土体强度衰减以及桩土界面摩擦因数的减小,从而模拟现场膨胀土含水率升高对膨胀土桩基上拔承载力的影响。着重对比分析了在浸水前后,扩大头埋深及扩大头直径对扩底桩承载特性的影响规律,从而实现膨胀土中扩底桩桩身尺寸的优化设计。

The problem of expansive soil has been paid more and more attention in the engineering world.There are a large number of transmission lines having been built on expansive soil in China.Using the existing experimental data on the medium-expansive soil,the method of elastic modulus reduction is adopted.With the increase of the expansive soil moisture content,the reduction of soil strength and the friction coefficient of the pile-soil interface are considered.Then the effect of elevated water content on the uplift capacity is simulated.The variation of the bearing characteristics of the expanded piles with different enlarged head depths and enlarged head diameters before and after immersion is calculated.The design of the size of the expanded belled piles in the expansive soil is thus optimized.