【作者】 何红前；

【导师】 彭建兵；

【作者基本信息】 长安大学 ， 地质工程， 2011， 博士

【摘要】 我国是世界上地裂缝灾害最为严重的国家之一,尤以渭河盆地地裂缝现象最为典型,造成的灾害最为严重。渭河盆地自有历史记载以来,就有多次地裂缝的发生。随着西部大开发战略的实施,大规模的城市建设如西安城市地铁、大同至西安高速客运铁路等工程都已无法避开这种特殊的地质灾害,因此有必要对渭河盆地地裂缝的成因机理展开全面而系统的分析和研究工作。本文在地裂缝野外调查和填图的基础上,广泛收集资料,综合利用多种技术方法和手段,深入了解渭河盆地地质环境背景,全面整理渭河盆地地裂缝的分布情况,揭示地裂缝的分布规律、活动特性,概化地裂缝的发育模式与成因类型,研究揭示地裂缝的成因机理,探索地裂缝的群发机理及预测预报地裂缝的发展趋势。本文主要研究工作和成果如下：(1)通过野外调查和资料收集,首次查明了渭河盆地现有136处共计191条地裂缝。渭河盆地地裂缝的发育在空间上具有明显的区域性和地带性特征,表现为盆地中东部发育,而西部不发育。其分布主要集中于盆地中南部的西安市、盆地北部边缘的泾阳县和三原县、盆地东北部的大荔县以及盆地中部的咸阳市。(2)通过对渭河盆地地裂缝发育状况的分析,首次揭示了渭河盆地地裂缝主要沿断裂带、地貌分界线附近、中小地震活跃区域分布的规律。(3)首次对渭河盆地典型地裂缝进行了精细勘探研究,系统地研究了渭河盆地地裂缝的基本特征,对盆地地裂缝进行了成因和亚类划分,分析总结了盆地地裂缝的成因机理,主要有盆缘断裂牵动模式、黄土构造节理开启模式、湿陷性地裂缝模式、地面沉降地裂缝模式、盆内隐伏断裂蠕动模式、地震地裂缝模式、主伸展断裂伴生+地面沉降耦合模式等不同类型。(4)在GPS观测资料和深部构造资料分析的基础上,建立了渭河盆地大陆变形的动力学模型,结合有限元数值模拟技术,确定了地裂缝群发与大陆变形之间的关系,结果显示渭河盆地NNW—SSE向的区域引张应力场在渭河盆地现代构造变动中占主导地位,是渭河盆地地裂缝群发的主要动力源。(5)首次对渭河盆地地裂缝的发展趋势进行了预测预报研究,找出了渭河盆地未来新地裂缝可能的发育位置,并应用地理信息系统技术,对渭河盆地地裂缝进行了危险性分区评价。更多还原

【Abstract】 China is one of the countries which ground fissure hazards are most serious in the world, especially in Weihe basin the phenomenon of ground fissures are most typical and the disasters caused by ground fissures are most serious. Since recorded history, there were many ground fissures occurred in Weihe Basin. With the implementation of western development strategy, large-scale urban construction, such as Xi’an city subway, Datong to Xi’an high-speed passenger rail and other projects have been unable to avoid this particular hazard, it is essential to carry out comprehensive and systematic analysis and research on the formation mechanisms of ground fissures in Weihe Basin.In dissertation, based on the field investigation of ground fissures and mapping, extensive collection of information, by means of a variety of technical methods, in-depth understanding geological environment background of Weihe Basin, the distribution conditions of ground fissures were arranged, the distribution rules and activity characteristics were revealed, development patterns and genetic types were concluded, the formation mechanism was researched, the group mechanism of ground fissures was studied, and the development tendency of ground fissures was estimated.The major research work and results of this dissertation are as follows:(1) By field investigation and data collection,191ground fissures in136places were ascertained for the first time. The distribution of ground fissures in Weihe basin has obvious regional characteristic and zonality characteristic in the space, which the central and eastern of Weihe basin is more, while the western is less. The distribution mainly focused on Xi’an City central and southern of the basin, Jingyang and Sanyuan County northern edge of the basin, Dali County northeast of the basin and Xianyang City central of the basin.(2) According to analyze the developmental state of ground fissures in Weihe basin, the distribution rules of ground fissures were found out for the first time, distribution along fault zone, landforms near boundary. Small and medium-sized seismic active regions.(3) Fine exploration was carried out to the typical ground fissures in Weihe basin for the first time, the basic characteristics of ground fissures were systematically studied, the formation and subtypes were divided, the formation mechanism was analyzed and concluded. There are several different types, such as basin margin fault breaking mode, loess structural joints opening mode, collapsibility ground fissure mode, land subsidence ground fissure mode, basin buried fault creeping model, seismic ground fissure mode, extensional faults coupling land subsidence mode, and so on.(4) Based on the analysis of GPS observation data and deep tectonic data, the dynamic model of continental deformation in Weihe basin was set up. Combining the finite element numerical simulation technology, the relationship between group ground fissures and continental deformation was determined. The results show that the NNW-SSE direction regional tensile stress field in Weihe basin hold a leading post in modern tectonic changing, which is the main power source of group ground fissures in Weihe Basin.(5) The development tendency of ground fissures in Weihe basin was predicted for the first time, and the development positions of new ground fissures were found out. By means of geographic information system technology, the risk assessment of ground fissures was conducted.更多还原