【作者】 孙炜锋；

【导师】 谭成轩； 雷伟志；

【作者基本信息】 中国地质科学院 ， 地质工程， 2009， 博士

【摘要】 近年来,地质灾害危险性评价已经成为人们普遍关心的主要问题之一。地质灾害危险性评价以地质灾害的防治为目的,在区域经济发展规划决策中具有特殊的重要性。地质灾害危险性评价研究成果具有广泛的应用价值,开展定量化地质灾害危险性评价研究是地质灾害研究今后发展的方向。目前地质灾害危险性分析理论还不完善,需进一步加强跨学科、跨领域的综合性研究,把地质灾害危险性分析与减灾规划、防治工程及社会经济紧密结合起来。伴随着人类不断的拓展生存空间的进程,今后更多的工程建设将会在各类斜坡体上进行,积极开展地质灾害危险性评价理论的研究具有重要的理论意义和实用价值。对于如何评价地质灾害危险性,目前还没有统一的理论方法。本文在全面分析宝鸡千阳典型粘黄土区地质灾害危险性主要影响因素的基础上,以地质灾害易发性评价为核心,按易发性评价—危险性评价的层递性顺序,对千阳县展开千阳县地质灾害危险性评价(区域)和千河谷地地质灾害危险性评价(重点地区)两个层次的地质灾害危险性评价,并结合千阳县典型黄土滑坡(塌山滑坡)稳定性评价为例,进行地质灾害危险性评价探索。主要研究结论如下:1.地质灾害易发性评价是地质灾害危险性评价的基础和核心。地质灾害易发性评价和地质灾害危险性评价都着重于考虑地质灾害的自然属性,区别之处在于易发性评价是对地形地貌、气象水文、地质环境条件、覆被等基础孕灾条件的综合评估,着重于解决滑坡等地质灾害发生的空间概率问题。而危险性评价更侧重于滑坡等地质灾害发生时会产生何种类型的破坏(毁损、掩埋等),以及地质灾害的规模、影响范围等问题。显而易见地质灾害易发性评价更注重于数学模型或专家经验的分析,因此在进行地质灾害危险性评价时,宜采取从易发性评价—危险性评价的层递性顺序。2.地质灾害易发性评价模型有各自的优点和局限性,在进行地质灾害评价时要综合运用各种方法进行整合分析,避免受到单个分析模型局限性的限制。层次分析法适用于对区域地质灾害有一定认识,但缺乏调查数据和定量分析,这时就可以用层次分析法得出仅是基于专家经验的地质灾害易发性评价;神经网络模型适用于对区域地质灾害缺乏调查资料,但有一定宏观认识和分析,这时就可以用神经网络法得出基于样本训练的有监督分类的地质灾害易发性评价;信息量法适用于对较大区域范围的地质灾害有大量调查数据,但缺乏定量分析,这时就可采用信息量法进行基于统计分析的地质灾害易发性评价;极限平衡条分法是较为严格的数学模型方法,对任何情况都适用。对比分析各数学计算模型的地质灾害易发性评价结果,可以看出,不同数学模型的评价结果不尽一致,这与各评价模型的简化假设和算法有关。在进行地质灾害易发性整合分析时,要综合考虑各评价方法的优缺点,对其地质灾害易发性评价结果进行合理性分析。不同的数学计算模型的评价结果在理论上都“包含”了“部分”的“真实解”。3.用于地质灾害危险性评价的最小单元既要反应出地形、地貌的基本特征,又要能体现斜坡的自然地质工程环境,因此地质灾害评价单元宜采用自然斜坡边界、地层岩性和断层共同圈闭的面域。4.塌山黄土滑坡在天然状态下较为稳定,但在饱水状态下有失稳的可能,各分析方法的安全系数最小值为1.26,接近欠稳定斜坡的临界值,沿指定滑面发生滑动的失稳概率为0.281%。塌山黄土滑坡在天然状态和饱水状态下失稳时的破坏形式相同,局部发生剪切破坏,滑动面位于滑坡后缘,剪出口位于滑体中部的居民开阔地,并未切入前缘沟底。更多还原

【Abstract】 Geological hazard assessment has become one of important problems that are popularly concerned with since 90s. Geological hazard assessment, aimed at hazard renovation, has special importance in planning and decision about economic development. The achievements in the risk analysis of geological hazard have widely practical value. It is a goal for the development of geological hazard study in the future that carryout the study quantitatively At present, the theory for the hazard analysis of landslide is not perfect, and it is needed to strengthen the comprehensive research cross subjects and fields, so that the risk analysis is combined with the planning of hazard reduction, protective construction and social economy. With the increasing need for land use in urban area, more constructions will be set on different kinds of slopes in future. So it is urgent to carryout positively the study on theory for geological hazard, which has important and realistic significance.There is no uniform theory system in the means of geological hazard assessment. Through the comprehensive studies on the factors influencing geological hazard, this paper established a case study on the geological hazard assessment in Qianhe valley and Qianyang County respectively. This paper also analyzed the stability of typical loess landslide (Tashan Landslide). Researches in the paper mainly include the following aspects:1. Based on the analysis of definition in geological hazard assessment, this paper taken geological susceptibility assessment as the core and basic study in geological hazard assessment. Geological susceptibility assessment is same to the geological hazard assessment in the point of analysis of nature background of geological hazards. Geological susceptibility assessment emphasized in comprehensive analysis of the geological hazards factors: landform, meteorological condition, hydrological geology, etc.. Geological hazard assessment emphasized in the style of the crash (damaged or buried), the scale of the hazard, the run out of hazard, etc.. It is appropriate to appraise the geological susceptibility assessment before geological hazard assessment in the process of geological analysis. In this sequence, we could distinguish the differential factors in the process of geological analysis.2. There are AHP method, information value method, ANN model and limited equilibrium slice method in the process of geological susceptibility assessment. Every method has its merit and deficiency. The AHP method is based on the analysis of experts, and is suitable in case of absence of investigation data but cognition of geological environment; ANN model is based on the method of monitoring classification, and is suitable in case of absence of investigation data but cognition of geological environment; Information value method is based on the statistic method, and is suitable in case of abundance investigation data of large-scale area. Limited equilibrium slice method is a rather strict mathematical technique, and is suitable in most cases. It is sound that to make an integration analysis in the process of geological susceptibility assessment, avoiding the deficiency of single method. It is reasonable to take the integration conclusion of different method as the better one because that every result of method comprised "partial" "real solution".3. The unit for the geological hazard assessment should have the properties of landform and the geological engineering of a single slope. Therefore, it is appropriate to take the surface of nature slope boundary, rock boundary and fault as the unit of geological hazard assessment.4. Tashan loess landslide is rather stable in nature state. In saturated state, Tashan loess landslide is unstable. The minimum FOS of Tashan loess landslide is 1.26 when saturated, approached the critical value of unstable slope, and the crash probability is 0.281%. Tashan loess landslide crashed in local part of the slide mass: the sliding zone located in the back of the landslide, leading edge is on the middle of settlement place, which is same whether in the state of nature or saturated.更多还原