【作者】 张英平；

【导师】 石建省； 刘长礼；

【作者基本信息】 中国地质科学院 ， 地质工程， 2012， 博士

【摘要】 本文为城市工程地质环境质量评价引入了一种新的评价模型。由于地质环境对工程建设的敏感性目前难以做出定量预测,工程地质环境质量评价一般通过构建合理的评价指标体系和确定权重来实现。城市工程地质环境质量传统评价方法中,指标权重确定后,无论各指标值如何变化,指标权重值总是固定不变,无法反映各项指标内部差异性对城市工程地质环境质量的整体性影响,进而影响评价结果的客观公正性。为此,将变权原理引入城市工程地质环境质量评价中。城市工程地质环境质量变权综合评价主要包括以下几个步骤：(1)根据城市工程地质环境特点及评价精度要求,构建郑州市区工程地质环境质量评价指标体系,并对评价指标进行等级划分；(2)根据城市工程地质环境质量评价指标体系,求出基础权重,也称“常权权重”；(3)运用MAPGIS图形处理模块将收集的评价指标数据,进行矢量化处理,再经过信息提取、赋值、缓冲区分析和DTM等处理过程,获得评价所需的具有新空间特征和新属性关系的单项指标栅格数据图层,并对它们统一坐标系统和投影方式,统一研究区域边界,建立评估指标体系数据库,同时对指标数据进行标准化处理及网格化剖分；(4)根据城市工程地质环境特点及评价精度要求,通过构建强惩罚—激励型状态变权函数对常权权重进行重新分配,求出基本评价单元的变权权重；(5)以栅格点状单元和矢量面状单元相结合,利用MATLAB关联变权综合评价模型,求出基本评价单元的综合评价值,然后再运用MAPGIS将属于同一工程地质环境质量等级的相邻评价单元合并,得到城市工程地质环境质量综合评价分区图。将变权综合评价模型应用于郑州市区工程地质环境质量评价,取得了如下认识和进展：1.在深入分析研究区工程地质环境特点的基础上,选取地形地貌、水文条件、工程地质条件、工程地质环境问题、地质灾害及人类影响6个影响城市工程地质环境质量的因素作为该评价系统的一级评价指标。再分别选取地貌单元、坡度、地面标高、地下水埋深、距地表水体的距离、地基持力层厚度、地基岩土体的均匀性、地基承载力、黄土湿陷性、砂土液化、软土层厚度、距活动断层的距离、地质灾害、地下水漏斗沉降量及人类工程活动15个因素作为二级指标,建立研究区城市工程地质环境质量指标评价系统,并采用模糊数学划分指标评价等级,利用层次分析法获得基础权重。2.城市工程地质环境质量评价系统是个分层次多指标的综合评判系统,评价时不仅应考虑各项评价指标对城市工程地质环境质量的影响,还应考虑各项评价指标内部差异性对城市工程地质环境质量的影响。根据评价时只要有一个指标值特差,哪怕该指标的常权值很小,最终综合评价值将显著减小；但单项指标值特高却不一定能使最终评价值增加明显的特点,建立了强惩罚—激励型状态变权函数。该函数通过初级惩罚阶段、强惩罚阶段、特强惩罚阶段对指标的“差值”进行惩罚,通过强激励阶段对指标的“优秀值”予以激励,而对于指标的“合格值”既不惩罚也不激励。该函数对于定性指标权重从每项指标只有一个权重调整为五个权重,对于定量指标权重则随着指标数值变化而变化。3.本文中MAPGIS采用了点状栅格单元和面状矢量单元相结合,使指标数据载体与基本评价单元分开实现,便于利用外部软件进行辅助计算。本文利用MATLAB编程解决了目前MAPGIS和EXCEL难以实现的复杂运算。4.运用常权模型和变权模型分别对郑州市深度8～9m的工程地质环境质量进行评价,得出：变权综合评价值域比常权综合评价值域离散性更好,较易划分评价等级；变权法与常权法综合评价结果趋势性较为一致,不同等级工程地质环境质量综合评价面积从多到少依次均为：Ⅲ、Ⅱ、Ⅳ、Ⅴ、Ⅰ。两种评价方法不同等级综合评价面积有所不同,面积变化从大到小依次为：Ⅲ、Ⅰ、Ⅳ、Ⅱ、Ⅴ。通过评价结果分析和实地调查可知,变权综合评价模型提高了城市工程地质环境质量评价等级的可信度和可靠度高,在一定程度上避免了常权法在权重分配中的缺陷,充分体现了各项评价指标内部差异性对城市工程地质环境质量整体性的影响。更多还原

【Abstract】 A new evaluation model was introduced to urban engineering geological environment quality. Geological environment is extremely sensitive to engineering construction, which cannot be predicted under present conditions. Quality evaluation of engineering geological environment is general implemented by constructing the reasonable assessment index system and determining these indexes’weights. Those traditional methods for quality evaluation of urban engineering geological environment can not reflect the effect of each index internal differences on urban engineering geological environment, which result in the final evaluation results lost their objectivities and justices. Once the index weights have been determined, they would never change with the index value variations. In this paper, the variable weight theory was introduced into the assessment system of urban engineering geological environment quality.Quality variable weight comprehensive evaluation for urban engineering geological mainly includes five steps:(1) Based on the characteristics of urban engineering geological environment and the evaluation requirements, the index system for quality evaluation of urban engineering geological environment was constructed, then classifications of the evaluation index was put forth.(2) According to the index system for quality evaluation of urban engineering geological environment, constant weights, also called "basic weights", were obtained.(3) According to the collected evaluation indexes data, those index images were obtained by vectorization processing of MAPGIS graphic processing module.The new spatial features and new relative attribute of grid date graph layer of every index was achieved by extracting information, assignment, buffer analysis and DTM process, while coordinate system, projection mode, study regional boundary were all unified. The database of evaluation index was established, and the data was standardized, then the index images were divided into many grids.(4) Based on the features of urban engineering geological environment and the evaluation precision requirements, the segmented strong penalty-incentive state variable weight function adjusted the constant weight, and the variable weights for every index of basic assessment unit were calculated.(5) Grid punctate units and vector surface units were coupled, the basic unit comprehension valuation values were calculated by association of MATLAB and the variable weight evaluation model. Merged the same quality grades of urban engineering geological environment, and then the comprehension evaluation zone map were finished.The variable weight comprehensive evaluation model applied to quality evaluation for urban engineering geological environment of Zhengzhou, and obtained the following knowledge and progress:1. Based on the analysis of engineering geological environment, topography and geomorphology, hydrogeology conditions, engineering geological problems, geological hazards and human influence were selected as the first level evaluation indexes of engineering geological environment quality. Topography, slope, ground elevation, groundwater depth, distance from surface water bodies, foundation bearing stratum thickness, foundation rock and soil uniformity, foundation bearing capacity, collapsible loess, liquefaction of sandy soil, mucky soil thickness, distance from activity fault, geological hazard, groundwater drawdown funnel and human engineering activity were selected as the second-level indexes, and then evaluation system for urban engineering geological environment quality was established. Classification of the evaluation index was adopted by fuzzy mathematics, and the constant weights were calculated by analytical hierarchy process.2. Urban engineering geological evaluation quality is a level-division and multiple index comprehensive evaluation system. Every index not only influences urban engineering geological environment quality, and every index internal different grades also impact its integrity. During the assessment process, the final comprehensive evaluation values reduce obviously, if one index value is worse, although its weight value is extremely low, but single index value is very high, the final evaluation values could not always increase obviously. Based on aforementioned characteristics, penalty-incentive state variable weight function was established. The function include three stages:primary penalty stage, intense penalty stage and ultra-intense stage, punished index worse values, inspired index excellent values, and index qualified values no punish no inspire. For qualitative indexes, the function adjusted its weight from one to five for each, while quantitative indexes, their weights changed with their values variations.3. Spotty unit and planar vector unit of MAPGIS were combined in this paper. Index data vector and basic evaluation unit were separated during quality evaluation process, easy to calculate. The complicated calculation was solved by using MATLAB programming, which MAPGIS and EXCEL hardly to implement under present conditions.4. The constant weight and the variable weight methods were respectively applied to assess urban engineering geological environment depth8-9m quality in main urban area of Zhengzhou. The analysis indicates that the discreteness of the variable weight comprehensive evaluation result is better than that of constant weight result, which easily distinguishes the quality grades of urban engineering geological environment. Two methods of evaluation result trends are consistent, different grades comprehensive evaluation areas of urban engineering geological environment quality from more to less in order are the third grade, the second grade, the fourth grade, the fifth grade, the first grade. Because index difference of urban engineering geological environment quality, the variable weight method using state variable function punished index worse values, inspired index excellent values, so evaluation areas of two methods are different. Different grade comprehensive evaluation changing areas of two methods from more to less orderly is the third grade, the first grade, the fourth grade, the second grade and the fifth grade. The analysis of two methods and field survey indicate the variable weight method significantly improves the reliability of quality evaluation grades urban engineering geological environment, therefore, the variable weight method avoids the defects of the constant weight distribution for urban engineering geological environment quality. More importantly, the variable weight method emphasizes punishing those indexes’worse values and encouraging those indexes’excellent values, no punishing and no encouraging qualified indexes, and this method fully reflects the influence of every index internal different grades on the comprehensive evaluation results of urban engineering geological environment quality.更多还原