基于权重反分析的岩溶地面塌陷危险性评价方法研究

Risk assessment method of karst ground collapse based on weight back analysis

为能快速、准确地对覆盖型岩溶发育区进行地面塌陷危险性评价,提出了基于权重反分析的岩溶地面塌陷危险性评价方法。该方法在确定岩溶地面塌陷主要影响因素的基础上,收集整理了唐山地区100个典型工程实例,进而采用权重反分析方法,求得了岩溶地面塌陷各主要影响因素的权重,并建立了岩溶地面塌陷危险性综合评价的评分表。权重反分析结果表明,选取的5个主要因素的权重分别为:岩溶发育程度0.338、第四系底部隔水层隔水能力0.255、覆盖层厚度0.186、基岩水水位埋深0.174、距断裂距离0.047,采用新建立的评分表对100个工程实例的评价结果显示,其评价的正确率达到99%,证明该表具有良好的可行性与有效性。此外,该评分表具有评价因子易于获取、评价过程简单易懂等特点,可准确、快捷地对与唐山岩溶发育区相似区域的岩溶地面塌陷危险性给出评价,因而值得推广和应用。

A new risk assessment method for karst ground collapse is presented in order to quickly and accurately assess the risk of surface subsidence in covered karst area. Firstly, the main factors were identified by mechanism analysis of karst ground collapse, and secondly the weight back analysis method was used to obtain the weights of main factors of karst ground collapse based on 100 typical engineering examples in Tangshan city. As a result, a score sheet of comprehensive hazard evaluation of karst ground collapse was established. Studies have shown that the weights of selected five main factors are as follows： karst development degree-0.338, water-resisting capacity of impermeable layer-0.255, overburden thickness-0.186, depth of bedrock water level-0.174, and distance from the fault-0.047. The karst ground collapse hazard evaluation results of the 100 project examples based on the proposed score sheet have shown that the correct rate is 99%,which can prove that the proposed method has a good performance in feasibility and effectiveness. In addition, the proposed method has the advantage of easy access of evaluation factors and high efficiency, and therefore it is worth popularizing and applying.