路堤荷载下碎石桩处理软基沉降计算

以沉降控制为目的的碎石桩复合地基,其沉降计算在设计、施工中具有重要地位。本文基于典型的桩土单元体模型,建立了复合地基体积压缩系数与复合地基弹性模量的关系,考虑施工中的时间因素及相应的固结度对沉降的影响,提出相应的沉降计算公式,并结合四川省遂-资高速公路软基变形监测的数据进一步验证其可行性。研究表明本算法计算值比实测沉降约大10% ～20%。填筑过程中,计算沉降历时曲线与实测曲线拟合较好,更接近实测值;在此基础上,初步探讨了影响路堤荷载下碎石桩处理软基沉降变化的因素,得出桩径、桩间距对其影响较为明显。同时结合本例,建议布桩时桩间距与桩径比值最好控制在2～4之间。

SETTLEMENT EVALUATION OF SOFT SOIL FOUDATION REINFORCED WITH STONE COLUMN DUE TO EMBANKMENT LOAD

Composite foundation aims at controlling settlement. Settlement calculation plays an important role in soft soil foundation design and construction stages. Based on the typical unit cell model of piles and soil, the relationship between composite foundation compression coefficient and elasticity modulus has been established. The factors such as time and consolidation have been taken into consideration. The settlements have been evaluated to verify the formula proposed in this paper. The formula is applied to the settlement deformation observation data of the soft ground distributed along the Suining-Ziyang expressway in Sichuan province. The formula's feasibility is further verified. The research shows that the calculation data are 10-20 times higher than the observed data. During the filling stage, the result calculated by the proposed method is in accordance with the observed results of the project. Based on these, the paper discusses primarily for the influential factors of the settlement such as pile diameter and the pile spacing. The best ratio of pile diameter and pile spacing is from 2 to 4.