地下工程渗流场有限元模拟研究

在水电、石油、交通等部门的地下工程中,经常会遇到地下水的渗流问题,如果处理不当,可能诱发应力恶化而影响结构稳定。本文以非饱和介质的渗流模型为基础,实现了地下洞室开挖过程中的非稳定渗流场解析。
按分期施工方案,在保持渗流场变化连续性的前提下,对各施工阶段进行了准稳定渗流分析,并在此基础上建立了地下工程非稳定渗流数值模型。其中,对于洞室系统,基于水量平衡原理,采用了子结构模型;对于防渗帷幕,采用了隔水层模型;对于排水井列,采用了杆单元模型。
根据上述模型,采用有限差分法作为数值模拟方法,编写了地下工程非稳定渗流场分析的有限元程序,实现了复杂渗流区域的渗流场的动态模拟。工程实例计算分析表明,用该模型计算的结果是合理的。 

THE STUDY OF FINITE ELEMENT SIMULATING OF SEEPAGE IN THE UNDERGROUND ENGINEERING

In the underground engineerings of waterpower, petroleum and traffic, the problem of seepage often happens. If it is not deal with correctly, worse stress will be induced, which willinfluence the stability of structure. Based on the model of unsaturated seepage, the analysis of unsteady seepage is accomplished.
In this paper, according to the construction by stages, under the continuity premise of seepages variance, the guasi-steady seepage for every stages is analyzed and accordingly a numerical model of three-dimensional unsaturated seepage is constituted. Based on the principle of water quantity balance the excavation is simulated with the model of substructure; the waterproof curtain with the model of interlayer; the drainge with the model of shank element.
According the above models a finite element program of unsaturated and unsteady seepage analysis is compiled using finite differnce method and the dynamical simulating of seepage field in complex region is done. The crnalysis and calculation of engineering case show that the results obtained by calculation of above models are reasonable.