考虑变质量的路基沉降应力变形协调分析法

Method of stress-deformation compatibility analysis considering variable mass for roadbed settlement

针对传统分层总和法存在小变形假定和无法考虑地基排水引起的质量变化等缺点,在不同参考构形等概念的基础上,重新解释了应变和压缩模量等度量的内涵,结合分层总和法和有限变形理论的基本思想,提出考虑变质量的应力变形协调分析法,用于计算最终沉降和固结沉降。对于排水和不排水路基的沉降问题,分析了最终沉降量的协调解与两种传统解的计算差别及其相对误差的变化规律,探讨了新方法在预测路基固结沉降中的应用。结果表明:最终沉降量的协调解和两种传统解均随着压缩层厚度的增加近似按双曲线规律增加,随着荷载的增加近似按线性规律递增;常用的不考虑应变历史修正的传统解计算结果偏小;协调分析法能提高预估路基固结沉降的精度等。用新方法可以更准确地计算路基的最终沉降和固结沉降。

The traditional layerwise summation method has such drawbacks as the assumption of small strain and the ignorance of variable mass due to drainage. In order to overcome the drawbacks, with the concept of different configurations, a new method of stress-deformation compatibility analysis considering variable mass due to drainage is developed, which re-explains the measurements of strain and modulus of compression, and which is associated with fundamental ideas of layerwise summation method and finite strain theory. Through the study of the subject of roadbed settlement under drained and undrained condition, the differences among compatibility solutions and two kinds of traditional ones for the ultimate deformation are presented as well as the corresponding regularity of relative errors, and the application of the new method to consolidation settlement of roadbed is also discussed. The results show that solutions of stress-deformation compatibility method and two traditional ones for the ultimate settlement increase approximately in hyperbolic curve with the increase of compression thickness, and increase nearly linearly as load level enhances; the generally-used traditional solution for the ultimate settlement regardless of strain history correction tends to yield a lower value; the new method can improve the accuracy of prediction for the consolidation settlement of roadbed, etc. The new presented method can help for evaluating both the ultimate settlement and the consolidation settlement of roadbed more precisely.