| 题名 | 大型地震滑坡动力过程与危害研究 |
| 作者 | 孙新坡 |
| 学位类别 | 博士 |
| 答辩日期 | 2012-05-22 |
| 授予单位 | 中国科学院研究生院 |
| 授予地点 | 北京 |
| 导师 | 何思明 |
| 关键词 | 地震滑坡 流固耦合 离散元 有限差分 流体力学 损伤机理 |
| 其他题名 | Large Earthquake Landslide Dynamic Process and Hazards Research |
| 学位专业 | 岩土工程 |
| 中文摘要 | 位于我国一二级地势阶梯的中西部地区因特殊的地质地貌条件和社会经济因素导致滑坡频发，灾害尤其严重。地震滑坡灾害具有面广，规模大，滑速快，突发性强的特点，常造成较其它山地灾害更重经济损失和人员伤亡，对中西部山区的经济和社会发展造成不良影响。目前国内外在认识滑坡机理上还存在诸多问题，已有的相关规范、规程也不能很好的满足安全高效治理滑坡的需求。现有机理研究也相对薄弱，多停留在以调查统计或模型实验为基础的宏观定性描述或半定量理论分析上，而对滑坡机理研究比较少，无法提供科学的判断方法和准则，还远未能满足山区发展对减灾防灾技术的需求。动力学模型则是建立在物理力学基础上的理论方法，能够考虑大型滑坡动力过程中的连续性条件、动量守恒条件以及复杂的边界条件。不仅能预测大型滑坡的运动距离、堆积区域范围，堆积厚度等重要参数，而且能给滑坡的运动速度、冲击能量、冲击力动力学指标，为大型地震滑坡的预测和工程防治提供依据。但大型滑坡的动力学模型的主要困难在于选择合适的物理力学参数，如何适应复杂的地貌条件。由于滑坡体滑动过程中非常复杂，连续模型很难模拟真实过程，而离散元是基于非连续基础上的，对模拟滑坡体滑动过程中的相互碰撞以及破碎很有优势。本文采用数值模拟的多种手段，主要采用离散元法，并结合有限差分，有限元和流体力学手段研究滑坡运动堆积以及和结构物相互作用和结构物破坏等。研究过程中获得的初步成果如下： 1. 基于水平集方程和流固耦合理论，分析滑坡碎屑流动力过程以及和障碍物的相互作用。结果表明，作用在障碍物上面作用力随时间很快达到最大值，随后出现波动。障碍物的变形特性在一定程度上降低了崩滑体的最大作用力，并且在时间上起到了延迟作用。作用在障碍物上面作用力随时间变化曲线以及压力和速度云图可以很好地证明了流体虽然未接触障碍物，但是空气介质对障碍物已经施加了作用力而使得障碍物变形。 2. 离散元程序PFC可以定性和定量地模拟地震滑坡碎屑流以及动力演化过程和堆积过程。通过反演滑坡运动堆积来获得合适的基底摩擦系数等来预测潜在滑坡的运动堆积危害范围。 3. 在本文数值模型中，采用三种模型，第一种模型：崩塌体由颗粒模拟，挡墙由刚性墙模拟；第二种模型：崩塌体由颗粒模拟，挡墙由颗粒模拟；第三种模型：耦合算法，崩塌体由PFC中颗粒模拟，挡墙由FLAC模拟。刚性墙模拟挡墙可以定性分析挡墙上面受力分析，而不能考虑变形影响，从而作用在挡墙上的作用力高于真实值。在PFC-FLAC耦合情况下，耦合情况和颗粒模拟挡墙变形吸收一部分能量，使得模拟结果更接近真实情况。颗粒模拟挡墙受力微观破坏发生的位置。通过受力和破坏分析来设计合理的防护结构。 4. 大型地震滑坡对承灾体的冲击损伤机理研究，崩塌滚石对沿程结构物的冲击破坏，以裂缝数与破坏时裂缝数的比值来定义易损性。设置不同边界条件和崩塌滚石冲击速度，来分析破坏形态，从而为工程结构的设计提供了理论和技术依据。 5. 针对彻底关大桥左侧的危岩体可能再次发生崩塌并严重威胁彻底关大桥的安全。本文提出了一种新型桥墩崩塌滚石防护结构，并对桥墩防护结构在崩塌滚石冲击下的动力过程进行了模拟研究。计算分析表明：桥墩在承受崩塌滚石冲击荷载下，桥墩防护结构降低冲击力30%，桥墩防撞能力显著提高。据此设计的桥墩防护结构已付诸实施，效果显著。按照本文设计方法进行的彻底关桥墩防护已得到实施，并经受了2个雨季的考验，目前运行良好 |
| 英文摘要 | In China the ladder of one and two in the Midwest because of the special geological and geomorphic conditions and social economic factors lead to frequent landslides, disasters especially serious. Because of the earthquake has wide landslide disaster, large scale, sliding speed fast, sudden strong characteristic, which are often cause mountain disaster than other economic loss and more heavy casualties, on the western mountainous area of economic and social development of a bad influence. At home and abroad and in the knowledge of landslide mechanism are still exist many problems, had the relevant specifications and rules also cannot meet the needs of the landslide control safety and efficiency. The existing mechanism study also relatively weak, and stay in the investigation and statistical or model on the basis of the macro qualitative description or half quantitative theoretical analysis, and the mechanism of landslide research is less, can't provide scientific judgment method and principles, but also far from the mountainous area development to meet the needs of disaster prevention and reduction technology. Dynamic model is established in the physical mechanics on the basis of the theoretical method, can consider large landslides in the process of the continuity condition, dynamic momentum conservation condition and complex boundary conditions. Not only to predict the movement of large-scale landslide accumulation of distance, regional, scope, piling up thickness of important parameters, and can give the power of the landslide speed, impact energy, impact dynamics target for large earthquake prediction and prevention and control of engineering of the landslide provides the basis. But the dynamic model of the large-scale landslide the major difficulties in choose the right physical mechanical parameters, how to adapt to the complex topography condition. Due to landslide sliding process is very complicated, and it is difficult to simulate real continuous model process and discrete yuan is based on a continuous basis, to simulate landslide in the process of sliding collision and broken very has the advantage. Based on the numerical simulation of a variety of means, mainly USES the discrete element method, than with finite difference, finite element, fluid mechanics landslide accumulation and means to study movement and structures interaction and structures such as damage, use in the course of the study have preliminary results are as follows: It mainly includes the following 5 points: 1. Based on the level set equation and the fluid-structure coupling theory, the landslide debris flow dynamic process and obstacles and the interaction analysis. The results show that, the function barrier in above with time reach maximum force quickly, then the volatility, the characteristics of deformation of the obstacles to a certain extent the collapse of the largest lower body force, and in the time delay in a role. Role in obstacles force changes with time above curve, the pressure and speed cloud images can be a very good proof, although fluid not contact obstacles, but through the air media on the obstacles have imposed force and make obstacles deformation. 2. Discrete program PFC can qualitative and quantitative simulate earthquake induced landslides and debris flow dynamic evolution process and the accumulation process. Through the inversion landslide accumulation to get the right movement base friction coefficient to predict the potential of such as landslide accumulation movement range of harm. 3. In this paper numerical model, adopt three model, the first model: collapse by particles body simulation, retaining wall by rigid wall simulation; The second model: collapse by particles body simulation, retaining wall by particle simulation; The third kind of model: coupled algorithm, collapse in PFC particles by body simulation, retaining wall by FLAC simulation. Rigid wall retaining wall can simulate the qualitative analysis on retaining wall force analysis, and can not consider deformation, and in the power of the retaining wall role in higher than the real value. PFC-FLAC coupling cases. Coupling and particle deformation part of the energy absorption simulation retaining wall, make the simulation results more close to the truth. The retaining wall force microscopic particles simulation damage occurred position. Through the force and the damage to design the reasonable analysis protection structure. 4. Large earthquakes to the impact of the landslide in body damage mechanism research, collapse of Rolling Stones along the riser structures destroyed the impact to crack number and the destruction of the ratio of the number of crack to define the vulnerability. Set up different boundary conditions and collapse impact velocity in the Rolling Stones, to analyze the damage form, thus for engineering structure design provides the theoretical and technical basis. 5. According to the left of the bridge are completely shut rock can happen again collapse completely shut a serious threat the safety of the bridge. This paper proposes a new bridge collapse a rolling stone gathers protection structure, and to the pier protection structure in the collapse of the Rolling Stones impact dynamic process simulation. Calculation and analysis show that suffered in the rolling stone bridge collapse under impact loading, pier protection structure reduce impact 30%, improved the pier crash. The root of this design of the bridge protection structure has been put into practice, the effect is remarkable. With this design methods of the pier protection has been completely shut implementation, and to withstand the test of two rainy season, the operation is good. |
| 语种 | 中文 |
| 公开日期 | 2013-01-11 |
| 内容类型 | 学位论文 |
| 源URL | [http://192.168.143.20:8080/handle/131551/4800]  |
| 专题 | 成都山地灾害与环境研究所_山地灾害与地表过程重点实验室 |
| 推荐引用方式 GB/T 7714 | 孙新坡. 大型地震滑坡动力过程与危害研究[D]. 北京. 中国科学院研究生院. 2012. |
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