考虑渗透系数随时间变化及固结状态影响的固结计算
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作者单位:

1.华东交通大学;2.江西省港航建设投资集团港航运输有限公司

基金项目:

国家杰出青年科学基金(51725802);国家自然科学基金-高铁联合基金(U1934208);江西省自然科学基金重点项目(20192ACB20001).


Consolidation calculation considering the change of permeability coefficient with time and the influence of consolidation state
Author:
Affiliation:

1.East China Jiaotong University;2.JIANGXI PROVINCIAL PORT&3.amp;4.WATERWAY CONSTRUCTION INVERSTMENT GROUP CO.,LTD;5.JIANGXI PROVINCIAL PORT&WATERWAY CONSTRUCTION INVERSTMENT GROUP CO.,LTD

Fund Project:

The National Science Fund for Distinguished Young Scholars ;Study on Long-term Performance Evolution and Big Date Analysis for Roadbed of High-speed Railways;Study on the influence of vehicle load adjoining deep foundation pit on mechanical properties of soil mass and safety of retaining structure

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    摘要:

    固结系数的不确定性是传统固结理论计算的局限性的根本原因,传统固结理论计算忽略了渗透系数k和孔隙比e在固结过程中随固结状态和时间的变化。基于此,本文基于工程常用的5种渗透系数预测模型,结合固结度和侧限压缩量的关系,推导出了孔隙比et的时间函数,构建了渗透系数与时间及固结应力依赖的计算公式。将所构建的渗透系数计算式代入太沙基理论中,同时考虑固结状态、固结应力及时间的影响,对经典Terzaghi一维固结理论进行修正。利用已有的试验数据进行对比,讨论预测公式的适用性。最后通过工程案例计算,与Terzaghi一维固结方程和其他修正固结理论对比,结果表明:当上覆荷载较大时,需要考虑固结系数Cv的变化;同时对比其他修正固结理论,说明了考虑孔隙比e和渗流系数k随时间变化过程的必要性。本文修正后一维固结方程更吻合工程实际,为预测地基固结提供了一种较精确的计算方法。

    Abstract:

    The uncertainty of the consolidation coefficient is the fundamental reason for the limitation of the traditional consolidation theoretical calculation, which ignores the variation of permeability coefficient K and porosity ratio E with the consolidation state and time during the consolidation. In this paper, the porosity time-history is derived on the basis of five commonly used prediction models of permeability coefficient in engineering, having the relationship between consolidation degree and unconfined compression. Thus, the calculation formula of permeability coefficient related to both time and consolidation stress is constructed. Here the one-dimensional consolidation theory is modified by substituting the permeability coefficient formula into the Terzaghi one-dimensional consolidation equation and considering the consolidation state as well as consolidation stress and time variation. The comparations with the literatures and engineering cases confirm the necessity of the time effect on the porosity. The change of consolidation coefficient Cv cannot be ignored when suffering a larger overlying load. The new version of Terzaghi one-dimensional consolidation equation is much more anastomotic with the engineering practice which provides a more accurate calculation method for predicting foundation consolidation.

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  • 收稿日期:2021-04-10
  • 最后修改日期:2021-04-27
  • 录用日期:2021-06-03
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