基于超高密度电法的某铁路穿越采空区工程稳定性评价研究

Research on engineering stability evaluation of a railway runs through a goaf based on high density electrical method

为合理评价甘钟铁路某段穿越采空区工程的稳定性,采用宏观识别和详细识别两阶段技术手段进行分析。宏观识别阶段,通过现场测绘、工程地质调查,并收集采空区既有煤矿地质报告后,基本查明采空区大致范围及采煤深度。详细识别阶段,为解决小窑采空区难以高效、精确测定的难题,基于现场地形条件及宏观识别阶段确定的大致范围及埋置深度,首先利用超高密度电法物探技术特有的分辨率高、定位准确、经济、灵活等特点,查明采空区精确分布范围、大小、深度及影响铁路范围。其次针对性地采用地质钻探验证超高密度电法探测结果的准确性,并进一步明确了采空区采动带、采动冒落带及裂隙带特征。基于两阶段技术成果,从地表变形特征、开采深厚比(H/M)和顶板岩土体对场地稳定性影响三方面对采空区稳定性进行了定性评价,结论为两处采空区处于欠稳定状态。定量计算表明,1#采空区地基不稳定,2#采空区地基欠稳定。结合定性与定量评价结果,综合评定2处采空区地基稳定性结果为欠稳定状态。

In order to reasonably evaluate the stability of a section of Ganzhong Railway crossing goaf,two stages of technical means of macro identification and detailed identification are adopted.In the macro identification stage,the general scope of the goaf and the depth of coal mining are found after site surveying and mapping,engineering geological survey,and collecting the geological report of the coal mine in the goaf.In order to solve the problem that small kiln goaf is challenging to measure efficiently and accurately,based on the field terrain conditions and the general range and burial depth determined at the macro identification stage,the precise distribution range,size,depth,and influence railway range of the goaf are identified first by using the characteristics of ultra-high density electrical geophysical exploration technology,such as high resolution,accurate positioning,economy,and flexibility.Secondly,geological drilling was used to verify the accuracy of the detection results of the ultra-high density electrical method,and the characteristics of the mining zone,mining caving zone,and fracture zone in Goaf were further defined.Based on the technical achievements of the two stages,the stability of goaf is qualitatively evaluated from three aspects:surface deformation characteristics,mining depth ratio(H/M),roof rock and soil mass influence on-site stability,and the conclusion is that the two goafs are in an unstable state.The QUANTITATIVE calculation shows that the 1#goAF foundation and the 2#GOAF foundation are unstable.Combined with the qualitative and quantitative evaluation results,the comprehensive evaluation results of the two goaf foundation stability are in an unstable state.