莘松高速公路软土地基处理及沉降

Ground Treatment and Subsidence of Soft Soil Base of Xin-Song Highway

本文叙述莘松高速公路沿线浅层土的软土特性、构造分类;介绍了软基处理的方法;以试验路段2.5年的沉降为研究对象,收集了近2000个沉降观测数据进行研究。分析了纵向、横向不均匀沉降的影响,低填土段的硬壳层效应和砂井的早期作用、验证了砂井布置密度渐变的设计方法的合理性。在应用双曲线型和指数曲线型公式推算最终沉降量后,提出以残余沉降、固结度、沉降速率作为综合评价地基稳定的条件。结合建设工期提出不同路段的竣工后容许沉降推荐值并建议采用固结沉降量计算法作为计算上海地区的路堤沉降量。

The article describes the characteristics and tectonic classification of superficial soft soil along Xin-Song highway as well as the method of treatment of fiexible base. Based on nearly 2000 settlement observations through two and oue-half years on the frial lot, the influences of vertical and horizontal unegual settlement, the effect of the crust in the low section embankment and the early stage effect of sand well are analysed and the reasonableness of the design method of gradually variable spacings of sand well is also verified. The final settlements have been calculated by using hyperbolic formula and exponential formula, it was pointed out that residual settlement, degree of consolidation and settlement rate can be used to comprehensively evalualuate the stability of the soil base of the highway. The allowable settlement at completion of different sections by taking the construction poriod into consideration has been recommended and a settlementclcalculation method based on cousolidation settlement has been suggested for highway settlement calculation in Shanghai area,