沪宁高速公路扩建工程软土地基处理和路基拼接技术研究

为减小路基拼接在新老路基间产生的差异沉降，从减小路堤荷载出发，研究了EPS轻质路堤填料在拼接工程中的应用；在加固地基方面针对传统地基处理方法处理深厚软基的缺陷，将PTC管桩应用于高速公路的拼接工程，设计中应按不同土质条件和工况采用不同的沉降分析计算方法，利用沉降观测资料反演分析所获得的地基参数可使计算获得较高的精度，文中推导的能反映地基层状性质和三维变形特征的带帽疏桩复合地基的桩、土应力比等计算公式，桩长、桩径、桩间距、桩帽尺寸及垫层厚度的优化设计方法，经实践证明具有较好的工程适用性。工程实践表明，采用EPS和带帽PTC疏桩处理地基拼接工程满足设计要求，处理效果明显。

Research on Soft Soil Treatment and Embankment Connection of Huning Expressway Extension Project

To reduce the load of the subgrade and different settlement in connecting,this paper researched the lightweight embankment filling,namely EPS,and analyzed its application in the constrution.Considering the defect of the traditional cement pile in treating deep soft soil ground, the PTC pile is applied in the expressway road widening.Different settlement analysis method of the road widening engineering should be used for different field condition.The parameter gained by the back analysis is used to raise the precision of the calculation.The equation of the stress ratio between pile and soil which shows the characteristic of layered soil and 3D settlement deformation of the rigid pile composite ground, and the optimizing design method of the pile length, the size of the pile cap,the diameter of the pile,the space between two piles and the thickness of the cushion have good engineering applicability.The practice proved that the use of the EPS and sparse rigid pile with cap in the road widening satisfy design request and have good effect.