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岩溶地质分形预报方法的应用研究

The Applied Study on the Fractal Forecasting Method of Karst Geology

【作者】 李苍松

【导师】 高波; 梅志荣;

【作者基本信息】 西南交通大学 , 桥梁与隧道工程, 2006, 博士

【摘要】 在大量的工程实践基础上,作者根据岩溶隧道施工所存在的问题-复杂的岩溶地质问题,抓住问题的重点和难点进行方法研究。 本论文主要在以下几方面进行了研究:1)岩溶发育分布的宏观规律及分形特征;2)岩溶发育的微观规律及分形特征;3)掌子面前方岩溶分形地质预报模型研究;4)岩溶围岩力学特性及岩溶围岩分级初步研究。 通过试验研究工作所取得的主要成果如下: 1).岩溶发育分布的宏观规律性:主要表现在区域平面分布和垂直剖面分布两个方面。首先在区域平面上,岩溶发育分布主要受岩石性质、地质构造、地下水动力条件及气候等因素的控制,其中岩性、构造和地下水是岩溶发育的三个必要条件。在岩溶垂直剖面三分带理论基础上,借助化学动力学水文地质理论,根据可溶岩的矿物溶沉规律,提出将方解石、白云石、石膏等矿物饱和指数加入到岩溶垂直分带中,增强了岩溶垂直剖面分带的定量化程度。对于岩溶涌水量及水压的预测问题,本文提出建立岩溶涌水的化学动力学水文地质模型,以期实现采用常规的水化学成分资料及可获取的基础地质资料,实现对岩溶隧道的分段涌水量预测。 2).不同的岩溶形态具有自相似性和标度不变性等两个分形图形的最重要特性。 3).提出岩溶元的概念。岩溶元或称溶蚀元(Karst unit),即岩溶形态发育的最小单元。岩溶元沿着微裂隙、节理等结构面或岩石表面按照一定的规律生长,并逐步生长为溶孔、溶缝、溶槽、溶管、以至于最终变为溶洞和岩溶暗河。 论文进行了不同条件下岩溶元的分形生长规律研究。首先,指出岩溶元分形生长的充分必要条件。然后,在宏观和微观控制条件下,岩溶元的分形生长机理按照不同的分形维数生长为不同的岩溶形态。论文指出了岩溶元的分形生长过程,其中的第N级生长结果就反映了特定条件下的岩溶发育程度或岩溶形态。同时,不同阶段的岩溶元生长所形成的不同岩溶形态与相应的岩溶岩体的工程质量级别是对应的,这就为利用岩溶元的分形生长结果进行岩溶分形地质预报奠定了理论基础,并为岩溶围岩分级奠定了理论基础。通过对岩溶分形曲线的相关系数和岩溶分形维数定性分析,可以定性描述被研究区域岩溶发育的可能性。于是提出岩溶发育程度的分形评价指数IKFA(the

【Abstract】 On the basic of large engineering practice, according to the complex karst geology problem of karst tunnel construction, the author grasped the major and difficult problem to research. The following main aspects are researched in the paper:1st, the macro-law and fractal character of karst development and distribution;2nd, the micro-law and fractal character of karst development and distribution;3rd, the forecasting model research of karst fractal-geology in advance of the excavation face;4th, the preliminary research of mechanical characteristic and classification of karst rock mass.From the test and research, the main achievements attained are as following:1).The macro-law of karst development and distribution: it mainly expressed on two aspects, that is, regional distribution and vertical section development. First, karst development and distribution are mainly controlled by factors on regional plane, such as, rock character, geologic structure, dynamic condition of groundwater, and climatic condition, etc. Among these factors, the three necessary factors are rock character, geologic structure and dynamic condition of groundwater. According to the regularity of mineral solution and deposition, it is suggested that mineral saturation index such as calcite, magnesium and gypsum be added to karst vertical section zoning, on the basic research of karst vertical section three-zone and the hydro-chemical kinetics theory, the quantitative degree is increased to karst vertical zoning. For the calculation problem of karst water quantity and pressure, a geo-hydro-chemical kinetics model of karst water is established. By using general water chemical component data and available basic geology data, it can be realized to forecast subsection water quantity in karst tunnel.

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