冻土路基动力分析模型及青藏铁路地震灾害评估

在大量试验研究成果的基础上,运用冻土物理学、冻土力学、数值传热学、高等土力学及土动力学等基本理论,建立了冻土区道路及铁道工程路基的水-热-动力耦合数学模型(有效应力法),并编制了相应的数值分析程序。最后,以青藏铁路某典型断面为例,对冻土铁路路基在地震荷载作用下的动力响应问题进行了系统分析,并评价了路基的地震安全稳定性。结果表明,提出的冻土路基动力分析模型合理,能较好地模拟冻土铁路路基的地震反应问题。另外,当发生设计烈度以下的地震时,青藏铁路路基不会产生严重破坏,经运营管理部门的维修后即可投入正常生产。

Dynamical analysis model for frozen embankment and seismic hazard assessment of Qinghai-Tibet Railway

Based on lots of experimental studies, a moisture, thermal and dynamic coupled model for frozen embankment is deduced by using fundamental principles of physics of frozen soil, mechanics of frozen soil, numerical heat transfer, advanced soil mechanics and soil dynamics; and then, its corresponding numerical program is written. Lastly, taking a typical section of Qinghai-Tibet Railway for example, the seismic response of frozen embankment is analyzed in detail; and safety stability of the embankment is assessed under the EI Centro earthquake loading. By this study, it is found that the dynamical model for frozen embankment proposed is reasonable and can well simulate the seismic problem of frozen embankment. In addition, the Qinghai-Tibet Railway will not be destroyed heavily under the seismic loading, of which the intensity is less than design value; and it can be immediately put into operation after simple repair.