软土路基下卧层固结分析

谢李钊，王星华，章敏

(中南大学 土木工程学院，湖南 长沙，410075)

摘 要：以某客运专线项目为研究对象，基于Merchant流变模型，提出软土路基层状黏弹性下卧层一维固结分析方法，得到软土路基下卧层不同时刻有效应力计算公式。采用MATLAB软件将本文计算公式编制成应用程序，作出几个主要影响因素对双层地基固结过程的影响曲线图。研究结果表明：半透水砂垫层的渗透系数对下卧层土体的固结有显著影响，随着渗透系数k₀提高，土体固结进程加快，固结完成的时间缩短；下卧层土层的Kelvin体弹簧的弹性模量和黏滞系数对有效应力都有较大影响，下层土弹性模量E_s2和 E₂越大，有效应力增长速率越大，固结速度越大，达到稳定状态的时间越短；加荷速率对固结的发展有明显影响，加荷速率越大，固结速度也相应越快。

关键词：路基下卧层；黏弹性模型；一维固结

Analysis of consolidation for soft lying-layer soil of roadbed

XIE Li-zhao, WANG Xing-hua, ZHANG Min

(School of Civil Engineering, Central South University, Changsha 410075, China)

Abstract:Based on Merchant rheological model, the analysis method of one-dimensional consolidation for double lying layered of soft soil under the roadbed was put forward, and the formula of the effective stress at different times was obtained. Using MATLAB software, the formula was compiled into the program, and the curves were made by several main factors to affect the consolidation process of the double layered foundation. The results show that the permeability coefficient of the semi-permeable sand cushion has a significant influence on consolidation of the lying layer of soil. With the increase of K₀, soil consolidation process is accelerated and consolidation time is shortened. The elastic modulus of Kelvin spring and viscosity coefficient of the lying layer of soil has great impact on effective stress. With the increase of E_s2 and E₂ of the bottom layer, the effective stress growth rate increases, consolidation speed increases, and the time that reaches a steady state is shortened, and loading rate also increases.

Key words:lying layer of soil under the roadbed; rheological characteristics; one-dimensional consolidation