青藏高速公路修筑对冻土工程走廊的热力影响及环境效应

The Qinghai-Tibet Engineering Corridor is a strategic channel between the Tibet and central China, in which some major liner infrastructures has been built. The controlling problem of environmental geology within the corridor is permafrost and fragile permafrost environment. For a major infrastructure, its construction and operation will be restricted by the environmental geology considerably. Meanwhile, the infrastructure’s construction and operation will result in significant influences on the environmental geology. This project will conduct a systematic research on the interaction mechanisms and processes between the permafrost environment and the projected Qinghai-Tibet Expressway. Methods including environmental background analysis, field monitoring, remote sensing, numerical simulation, and laboratory model test will be used during the research. The aim of the research is to reveal the thermos-mechanical influences of the expressway on permafrost along the corridor and related environmental effects. Then, the influence of these environmental geology effects on the existing infrastructures within the corridor will be predicted and evaluated, especially the negative influences on the cooling effects and long term thermo-mechanica stability of cooled roadbed along the Qinghai-Tibet Railway. Based on the research of this project, an active control theory and countermeasure system for interaction of engineering and permafrost environment will be constructed and developed. The research will solve the related basic theoretic and key technical problems for the expressway’s building and the existing infrastructures’ maintaining in the corridor. And some original achievements on the interaction of permafrost engineering and permafrost environment elements, and interaction between infrastructures group along the corridor are expected with confidence.

青藏工程走廊是连接西藏与内地的战略通道，廊内控制性环境地质问题是冻土，已建数条重大工程聚集于这一狭窄地质环境脆弱敏感带内。重大工程建设受到地质环境制约的同时，也将产生显著的地质环境效应。项目采用环境背景分析、现场监测、遥感技术、数值模拟及室内模型试验等方法，开展新建青藏高速公路与走廊冻土地质环境相互作用及其环境效应研究，全面揭示和掌握高速公路工程修筑对走廊多年冻土热力格局的影响及引发的小气候、风沙及浅表层径流等环境效应的机制和程度，预测评估新建工程地质环境效应对走廊已建重大工程，尤其对青藏铁路主动冷却路基降温机制及长期热力稳定性的影响及程度，进而发展和完善重大工程与冻土地质环境多要素相互作用的多层次主动调控理论与次生冻融灾害防治体系；解决保证高速公路建设、保障既有重大工程安全运营的基础理论和关键技术问题，有望在工程与冻土地质环境多要素相互作用机理及走廊构筑物群相互作用领域取得独创性成果。

面对拟建青藏高速如何建设以及走廊内已建生命线工程科学维护，项目聚焦“青藏高速公路修筑对冻土工程走廊的热力影响及环境效应”，结合现场监测、模型试验、理论分析和数值模拟手段，取得了如下主要成果：.1）建成了“青藏高原高速公路工程环境效应综合观测系统”，首次获得了完整的高速公路工程近地表风速、风向、空气温湿度、地表辐射/温度、路基阴阳坡面温度、水分、浅层土体热通量、降水、路基横向变形实测数据集。可为高速公路工程环境效应评估及相关研究提供关键数据支撑。.2）建成了冻土路基冻结层上水观测剖面2个；结合已有观测断面和现场调查，研究了地表积水对路基长期热力稳定性影响机制，提出了“三位一体”的冻土路基水致灾害处置方案。建成了高速公路冻土路基侧向变形观测系统，研究了冻土路基侧向变形潜在机理并提出了理论模型，为建立冻土路基二维变形与病害发育理论提供了重要基础。.3）开展了青藏铁路、公路野外病害调查，获得了典型区段工程病害及次生冻融灾害资料，评估了冻土工程病害与次生灾害发育环境、过程及关键致灾因素。.4）揭示了青藏铁路、公路路基横向热影响机制，模拟评估了高速公路修筑对青藏铁路路基的潜在影响，提出了拟建青藏高速的布设原则和并行线路布设间距。结合大型风洞试验，开展了携沙风绕流路基工程的模拟研究，量化了风沙灾害对冻土路基长期热力稳定性影响。.5）建立了青藏工程走廊冻土场地反应分析模型，研究了不同类型多年冻土场地地震特征及关键影响因素，为走廊区带内地震区划、重大冻土工程地震安全评价提供参考。.6）初步形成了重大冻土工程面向地质环境多要素调控理论，明晰了重大工程与冻土地质环境多要素相互作用和线性冻土工程构筑物群间热力相互作用，系统评估了现有主动冷却措施的效能，提出了拟建青藏高速保护冻土的设计原则。.研究成果将有效服务于新建高速公路工程环境效应评估、冷却路基结构选型与优化、线性构筑物合理布局以及青藏铁路、公路等重大生命线工程的科学维护。