为建立科学系统的“地质−工程”一体化地质风险评估模式，解决煤炭地下气化(UCG)选址选层难题，提出了一种以“建炉可行性、过程易控性、气化安全性、开发经济性”四性认识为基础，利用FAHP模糊层次分析法创建的包括4项一级指标、10项2级指标、26项3级关键地质参数的地质评价要素层次结构模型。该模型引入“阈值”概念，对断层指数、奥亚膨胀度、黏结指数、上覆含水层距离4项指标的超“阈值”情况实施“一票否决”，充分重视特定地质参数对UCG控制的关键作用；通过“两两判断矩阵”确定各指标权重向量，根据隶属函数厘定指标层隶属度；并提出了相应地质评价技术方法，配套建立了权重积、综合权重积以及最优3段分割等算法，将所涉及指标量化分析，精准判断资源类型与级别；同时基于矩阵结构混合编码方式，提出了“四性四级”五位编码的UCG资源类型表征系统。最终形成了以“四性”理论为基础，“算法”为骨架，“四性四级”五位编码为灵魂的科学化、系统化UCG选址选层地质评价体系。该评价体系可在多场耦合的UCG生产过程相关风险识别机制的前沿探索方面发挥关键作用，有效改善现有UCG风险识别理论局限于地质单方面，缺乏工程联系的问题，实现大区域的UCG量化选址选层，为省级乃至国家级煤炭地下气化战略规划提供解决途径，从而提出可供分步实施的典型地质条件先导性试验区建议，推动煤炭地下气化产业化进程。

In order to establish a scientific and systematic “geology-engineering” integrated geological risk assessment model, so as to solve the problem in the site and layer selection of underground coal gasification (UCG) project, a new hierarchical structure model of geological evaluation elements including 4 first-level indicators, 10 second-level indicators and 26 third-level key geological parameters is established using the FAHP fuzzy analytic hierarchy process based on the four characteristics of 'feasibility of furnace construction, easy control of process, safety of gasification and economy of development'. The model introduces the concept of “threshold”, and implements “one-vote veto”when exceeding the thresholds of the four indicators including fault index, Oya expansion degree, bond index and distance of overlying aquifer, and pays full attention to the key role of specific geological parameters in the UCG control. The weight vector of each index is determined by “pairwise judgment matrix”. According to the membership function, the membership degree of the index layer is determined. The corresponding geological evaluation techniques and methods are put forward, and the algorithms of weight product, comprehensive weight product sum and optimal three-segment segmentation are established, so as to quantitatively analyze the indicators involved and accurately assess the type and level of resources. In addition, based on the mixed coding method of matrix structure, a UCG resource type representation system of “four properties and four levels”five-bit coding is proposed. Finally, a scientific and systematic geological evaluation system of UCG site and layer selection is formed, which is based on the understanding of “four properties”, “algorithm” as the skeleton, and “four properties and four levels” five codes as the soul. This evaluation system can play a key role in the frontier exploration of risk identification mechanism related to UCG production process with multi-field coupling. It can effectively overcome the problem that the existing UCG risk identification theory is limited to geological unilateral and lacks engineering connection. In order to realize the UCG quantitative site and layer selection in a large area, it provides an efficient solution for the strategic planning of underground coal gasification at the provincial and even national levels. The study puts forward the suggestions for the pilot test area of typical geological conditions that can be implemented step by step, and effectively promote the industrialization process of underground coal gasification.