多年冻土路基随机热力耦合可靠度研究

The reliability of permafrost subgrade is still challenge to transportation construction and operation management in permafrost region. The deterministic analysis method is not satisfied with the demand of analysis reliability for permafrost subgrade due to the randomness of the thermal and mechanical parameters of frozen soil and complexity of environment surrounding. So, the aim of this project is to build theoretical system of random reliability for permafrost subgrade and work out the software corresponding. The main research content including: firstly, the parameters of permafrost subgrade are considered as random fields to discrete based on the random fields theory and characteristic parameters are calculated. Secondly, the theoretical model of stochastic finite element for permafrost subgrade will be set up based on the thermal and mechanical stochastic variation principle built respectively and the formulations of stochastic finite element derived consequently. According to failure mode of permafrost subgrade and reliability theory, the model of random reliability for permafrost subgrade will be worked out. Finally, the program will be finished and checkout its accuracy by means of comparative analysis. The parameter sensitively analysis, the instability mechanics and reliability index for the permafrost subgrade in site will provide guide and technology support to the permafrost subgrade design,construction and reliability assessment. The complete of this project has important academic value and broad engineering application prospects in permafrost engineering.

在多年冻土地区进行交通建设以及运营中，冻土路基的可靠性是至今未能解决的难题。由于冻土路基环境及冻土本身热力学性质的复杂性、随机性，传统确定性的分析已不能满足冻土路基可靠性分析。因此，本项目旨在研究冻土路基的随机可靠度计算理论中必须解决的两个主要问题。一、从随机场参数离散理论出发，结合试验研究，确定冻土热-力学参数的变异性与相关性理论，揭示其与含水量、温度的关系；二、建立在大扰动随机参数条件下多年冻土路基热力耦合随机变分原理，推求热-力耦合随机有限元列式，建立冻土路基随机热力耦合有限元的理论模型。根据多年冻土路基的失效模式，应用可靠度理论建立多年冻土路基可靠性模型和数值计算模型。通过对多年冻土路基进行可靠度及参数敏感分析，探索、预测冻土路基的失稳机理与可靠度，为多年冻土地区路基设计、施工和可靠度评价提供理论指导和技术支持，项目完成具有重要的学术价值和广阔的工应用前景。

在多年冻土地区进行交通建设以及运营中，冻土路基的可靠性是至今未能解决的难题。由于冻土路基环境及冻土本身热力学性质的复杂性、随机性，传统确定性的分析已不能满足冻土路基可靠性分析。因此，本项目旨在研究冻土路基的随机可靠度计算理论中的两个主要问题。一、从随机场参数离散理论出发，结合试验研究，确定冻土热-力学参数的变异性与相关性理论，揭示其随机场的数字特征；二、建立了随机参数条件下多年冻土路基热力耦合随机变分原理，推求热-力耦合随机有限元列式，建立冻土路基随机热力耦合有限元的理论模型。三、根据多年冻土路基的失效模式，应用可靠度理论建立多年冻土路基可靠性模型和数值计算模型。并通过对多年冻土路基算例对冻土路基的可靠度与稳定性进行分析，为多年冻土地区路基设计、施工和可靠度评价提供理论指导和技术支持，项目完成具有重要的学术价值和广阔的工应用前景。