条形荷载下黄土地基沉降基础尺寸效应分析

Analysis on Loess Foundation Settlement Considering the Foundation Size

以均质和层状黄土地基为例就条形荷载下地基沉降的基础尺寸效应问题进行计算研究。在基底压力不变情况下,地基沉降量随着基础宽度的增加呈非线性增加,但随着基础宽度的增加,沉降增量逐渐减小。对上硬下软双层地基,在基底压力和基础宽度一定情况下,基础宽度取值越小,上层厚度变化引起的沉降差异越小,基础宽度越大,宽度增量导致的沉降增量越小。对于上部荷载恒定的条形基础,地基沉降量随着基础宽度的增加呈非线性减小,在基础宽度一定情况下,基础宽度取值越小,双层地基上层厚度变化引起的沉降差异越大,基础宽度较小时地基沉降对其宽度变化较敏感。对于小尺寸基础,采用增大基础宽度减小地基沉降的方法是有效的,但对于大尺寸基础,则不宜采用增大基础宽度减小地基沉降的方法。

As an example of homogeneous and layered loess foundation,studies on foundation dimensional effect on loess subgrade settlement under strip load were carried out.The foundation settlement under uniform loading is nonlinearly increased along with the increase of strip foundation size.However,as increase in foundation width,the settlement is gradually reduced.To the double layer foundation which is formed by hard overlying and soft underlying layers,the differences in settlement which caused by the change of overlying thickness under uniform loading and same foundation size is smaller when the foundation size is smaller,and the settlement caused by the increment of foundation width is also smaller when the foundation size is much larger.The foundation settlement under fixed top loading is nonlinearly reduced along with the increase of foundation width,the difference in settlement which caused by the change of overlying thickness in double layer foundation under the same foundation size is much larger when foundation size is smaller,and the settlement is more sensible when the foundation size is much smaller.For the small foundation,increasing its size in order to reduce the settlement is effective,but for the large foundation,it is inadvisable to use such method.