黄土滑坡的人工振动促渗促滑机理研究

With the development of the large west construction, the effect on environment of loess plateau caused by human engineering activities is more and more serious, which caused so many geo-hazards and environmental degradation. Therefore, in this project we choose the natural.test field, in which the nature and human interaction so frequent that we could conduct the study on the mechanism of the effect induced by human engineering activities. This project will start from the landslides along the high-speed railway, hill city and airport’s track which built on loess ridge. The problems that puzzled researches for long time in the loess landslides research will be talked and analyzed deeply. Based on the in-situ wave monitoring, model test and the numerical computing, and the elastic-plastic theory, mechanics of vibration, percolation theory and vibrational principle will be used in the study on mechanism of loess landslides induced by the promoting penetrative and sliding effect of artificial vibration, which induced by the blend effect of the train vibration (long-duration and small aptitude) or dynamic compaction vibration (heavy weight and multiple repetition). The influence factors of these landslides will be explained, and the full-process evolution model will be established. Based on the aforementioned research, several new formation and evolution mechanisms of loess landslides will be given. All these study will be applied on the geo-hazards prevention and control in loess plateau, and can also provide scientific and theoretical basis for the sustainable development of local economy.

随着西部大规模基础建设的开展，人类工程活动对黄土高原的影响日益剧烈，导致了地质灾害频发、环境不断恶化。为此，本申请选择黄土高原这一人类与自然交互作用的天然试验场来研究人类工程活动对环境的影响机理。项目实施拟以黄土高速铁路沿线、山城和机场移山填沟周边等滑坡为突破口，选择长期困扰人们的黄土滑坡特殊症结，层层解剖、深入探讨。以现场监测、模型试验及数值计算为手段，利用弹塑性理论、振动力学、渗流理论及变分原理等探索滑带黄土在高速列车“长持时、小振幅”和强夯振动“大吨位、多重复”等特殊人工动力荷载下的促渗促滑机理；揭示黄土滑坡在其作用下的各种变形破坏规律（振松振裂效应和促渗促滑效应）；摸清这些黄土滑坡的影响因素；建立这些类型滑坡的全过程演变模型，提出其形成与运动机理的几种新观点。为黄土高原灾害防治、环境保护及地方经济可持续发展提供科学依据和理论基础。

随着西部大规模基础建设的开展，人类工程活动对黄土高原的影响日益剧烈，导致了地质灾害频发、环境不断恶化。针对黄土区工程建设的两种重要的人工振动（机车振动和强夯振动）诱发的黄土地质灾害的影响因素和机理，项目组五年来紧紧围绕这两个方面开展研究，取得了一系列的成果。.代表性成果包括：①项目组首次探究了强夯振动和机车振动在斜坡的动力响应规律，揭示了不同夯锤直径、能级的组合下不同含水率、压实度等土层中动土压力和加速度的变化规律，提出了机车振动在不同地貌单元的衰减规律；②自主研发了振动促裂仪和振动促渗仪，首次通过室内试验验证了机车振动与水联合作用下“四促效应”的科学性，发现了机车振动导致黄土的抗拉强度和粘聚力显著降低，揭示了机车振动加快水在黄土中的渗透与提高饱和程度的振动促渗效应；③开展岩土本构关系与数值模拟、边坡稳定性及土的动力分析研究工作；探讨含水状态变化对黄土结构的损伤效应；从宏细观角度探索含水状态变化对黄土边坡促渗促滑机制；④结合土动力学试验，在黄土的静动三轴试验基础上，研究人工振动荷载作用下黄土结构损伤效应，结合弹塑性力学、损伤理论和统一强度理论，建立黄土的损伤本构模型；⑤基于室内试验和数值分析的方法，提出了不同影响因素下强夯振动的安全距离的加速度临界值，揭示了机车振动与水联合作用下黄土促滑机理，并发现了机车振动与水联合作用下“四促效应”之间的关联性。通过本项目的顺利开展，一方面为黄土区铁路、高山机场和移山填沟工程提供了科学理论依据；另一方面丰富、完善和提高了黄土区人类工程活动诱发的黄土地质灾害的理论和技术。因此，本项目的研究成果具有很强的理论和实践意义，并对今后的黄土区工程建设和黄土地质灾害前沿科学问题的研究起到了良好的示范和推动作用。