上海地区沉桩阻力估算方法分析探讨

Study of Pile-sinking Resistance Estimation in Shanghai Region

分析了估算沉桩阻力的必要性。在简单介绍了上海地区土层特性的基础上,按照桩端持力层土层性质和桩侧土性质的不同组合,将上海地区地基土分为4类进行研究。选择了4个具有代表性的已有计算沉桩阻力的计算公式,针对不同地基土类型,分别利用大量工程实测数据对各公式进行了分析研究,结果表明没有一个公式普遍适用于各种地基土。在分析各公式在不同地基土中的优缺点的基础上,提出了推荐使用的以静力触探比贯入阻力PS值为主要参数,同时考虑土体灵敏度和侧阻力、端阻力深度修正的沉桩阻力估算公式。运用大量的工程实测数据对该公式进行了验证,结果表明对不同的地层组合都比较适合。推荐公式对判定静压桩沉桩可能性和施工设备选型具有参考价值。

The necessity of the resistance of pile-sinking estimation was analyzed. The soil properties in Shanghai region were introduced, and the foundation soils were separated into four classes based on the soil properties around pile. Four representative formulae on the estimation of pile-sinking resistance were selected, and their applicability was evaluated with a great deal of measured data of projects. It shows that none of the formulae is available to the foundation soils of all four classes. With the analysis of the advantages and disadvantages of the formulae, a more suitable estimation formula was proposed. The main parameter of the proposed formula was static penetration resistance (Ps), meanwhile the soil sensitivity and the depth amendment of soils resistance were considered. The evaluated results from many-measured data of projects prove that the proposed formula is available to the foundation soils of all classes. The formula can guide to judge the possibility of pile sinking and select the construction equipment.