黄土隧道地层浸水劣化机理及结构承载理论研究

隧道工程尤其是城市隧道周边管线众多，人工水域修建频繁，由于管网渗漏、地表蓄水引起的地层局部浸水和地下水位抬升对湿陷性黄土隧道安全影响明显，加之黄土工程性状特殊性及相关理论不完善，使其存在较大安全隐患。目前对黄土隧道地层浸水劣化机理、浸水条件下结构承载理论及计算方法的科学认识尚不明确。本项目拟结合工程实例，在申请者已开展的黄土隧道系列研究基础上，采用以理论分析为基础，室内试验、物理模型试验、数值模拟、现场测试相结合的方法，借助CT数字全息动态显微技术、高精度微传感技术和局部离散耦合解算技术，进行浸水过程土体微观动态剖析、高精度监测物理模型试验、离散介质本构模型开发和局部离散数值计算，建立水流运移扩散与黄土湿陷性态模型，揭示黄土隧道地层湿陷演化机理及地层响应规律，提出适用于黄土隧道浸水工况下的结构承载理论及计算方法，并完善黄土隧道地基变形评价体系，提升我国黄土隧道建造理论水平及容灾能力。

There are many pipelines around the tunnel project, especially the urban tunnel project, and the artificial water area is built frequently, leakage of pipe network, local stratum flooding caused by surface water storage and rise of underground water have obvious influence on the safety of collapsible loess tunnels. In addition, the particularity of loess engineering properties and the imperfection of theoretical research make it have great potential safety problems. At present, the scientific understanding of the mechanism of water degradation in loess stratum, the theory of structural bearing capacity and the calculation method of tunnel under the condition of water immersion in loess stratum tunnel is not clear. Combining with the engineering example, this project plans to adopt the method of combining the indoor geotechnical test, physical model test, numerical simulation, field test and theoretical analysis, based on the applicant's series theoretical research of the loess tunnel. In the research process, CT digital holographic dynamic microscopy technology, high-precision micro-sensing technology and local discrete coupling calculation technology will be used to analyze the micro-dynamics of soil in the process of flooding, high-precision monitoring model test, discrete element constitutive model development and local discrete numerical calculation. The model of water flow migration and diffusion and loess collapsibility will be established, and the evolution mechanism and response law of strata in loess tunnel will be revealed. This project will put forward the theory and calculation method of structural load bearing applicable to the loess tunnel under the flood condition, and will improves the evaluation system of the deformation of loess tunnel foundation, so as to improve the theoretical level and disaster capacity of loess tunnel construction in China.