浅层固化层应力扩散效果分析及优化设计

Analysis of Stress Diffusion Effect in Shallow Solidified Layer and Optimization Design

摘要:

就地固化技术形成的人造硬壳层的实际处理效果受设计施工影响大。以南京某软基就地固化处理段为工程背景，建立Plaxis 2D有限元模型，通过不同浅层固化层设计参数计算结果对比，分析低路堤荷载作用下地基附加应力系数与路基沉降分布规律，探究固化层的应力扩散效果，同时结合下卧软土层超静孔压的消散特征，对现有固化方案进行优化设计。结果表明，固化层的抗弯刚度是应力扩散效果的主要控制因素，固化层厚度小于1 m、宽度超过路基宽度或与下卧软土接触面Rinter大于0.4，对应的固化层模量或厚度的变化对路基沉降影响很小，同时综合固化层应力扩散效果、路基沉降影响因素及地基孔压消散规律，提出对固化层设计的合理性优化建议。

Abstract:

The actual treatment effect of artificial hard shell formed by the local curing technology is greatly affected by the design and construction. Based on the local curing treatment section of a soft foundation in Nanjing, a Plaxis 2D finite element model is established. Through the comparison of the design parameters of different shallow solidified layers, the distribution of additional subgrade stress coefficient and roadbed settlement under low embankment load is analyzed. The stress diffusion effect of the solidified layer is explored. At the same time, combined with the dissipation characteristics of the superstatic pore pressure in the underlying soft soil layer, the existing curing schemes are optimized and designed. The results show that the bending stiffness of the solidified layer is the main factor to control the effect of stress diffusion. The thickness of the solidified layer is less than 1m, the width exceeds the width of the roadbed or the contact surface Rinter with the underlying soft soil is more than 0.4. The corresponding change of the modulus or thickness of the solidified layer has little effect on the settlement of the roadbed. At the same time, by synthesizing the stress diffusion effect of the solidified layer, the influencing factors of the roadbed settlement and the dissipation law of the subgrade pore pressure, the reasonable optimization suggestions are put forward for the design of the solidified layer.