基于Mindlin-Geddes法计算桩基沉降

近年来,我国很多城市发生了大面积地基沉降问题,其影响因素是多方面的,如由于填海造地,沿海地区地基处于欠固结状态,以及大规模的密集高层建筑物群等因素。基于Mindlin-Geddes应力解,并根据叠加原理计算群桩内任一点处的应力,采用分层总和法计算桩-箱基础内任一点处的沉降量。该方法考虑了桩与土,桩与桩之间的相互作用,能够计算复杂基础形式的群桩沉降问题,尤其是由于复合桩侧摩擦阻力造成的地基沉降。并以深圳某办公楼为算例,考虑周围两栋建筑物对其沉降的影响,应用此方法计算的最终沉降量与实际的沉降量很接近,达到计算精度要求,可为群桩设计提供指导。

THE APPLICATION OF MINDLIN-GEDDES METHOD IN THE CALCULATION OF PILED FOUNDATION SETTLEMENT

In recent years,a number of large land subsidence events have occurred in many cities of China. Factors affecting land subsidence are multifaceted. Because of land reclamation in coastal areas,the foundation is under-consolidation state,as well as large-scale intensive high-level group of buildings and other factors. Based on the the Mindlin-Geddes stress solution,this paper calculates the stress of the pile group at any point,according to the principle of superposition,and the layer-wise summation method is used to calculate the pile-box foundation settlement at different points. The method takes into account the interaction between piles and soil,and that between piles and piles,thereby being able to calculate the settlement of group piles of a complex foundation,especially the foundation settlement caused by the side friction resistance of composite piles. Taking an office building in Shenzhen for example,the influence by two buildings arround on its settlement is considered. The calculated results are very close to the actual settlement,which is up to the computational accuracy,which can provide guidance for the pile group design.