高速铁路采空区地基活化判据与工程实例分析

Analysis on Activation Criterion and Engineering Example of High-speed Railway Foundation in Goaf Site

为探究高速铁路采空区地基活化问题,基于附加应力分析法,以引起叠加附加应力值等于5%岩土层自重应力的深度为附加应力影响深度,推导出高速铁路有砟轨道双线路堤段及路堑段在无列车、有列车情况下的附加应力影响深度计算公式,提出了以附加应力影响深度与垮落断裂带深度大小关系为依据的采空区地基活化判别标准,并分析了高速铁路采空区稳定性影响程度的评价标准。以沁水煤田太焦高速铁路为工程实例,研究结果表明:高速铁路在采空区地基附加应力影响深度从大到小分别是列车交会、单车、无车;路堤段在采空区地基中附加应力影响深度大于路堑段;路堤段与路堑段在采空区地基中附加应力随深度衰减规律相同;随着路堤高度的增加,附加应力影响深度几乎成线性增加。

In order to investigate the activation of the goaf ground under a high-speed railway,based on the additional stress analysis method,considering the depth where the superimposed additional stress value equals 5%of the self-weight stress of the geotechnical layer to be the additional stress in-fluence depth,formulas for the additional stress influence depth of the embankment section and the graben section of the double-line ballast track of high-speed railway in the case of with or without train are derived.The standard for activation criterion in the goaf ground based on the size of the relation-ship between the influence depth of additional stress and the depth of collapse fracture zone is pro-posed.The evaluation criteria for the impact degree of the stability of the goaf under the high-speed railroad are analyzed.The results of an engineering example study on the Taijiao high-speed railroad in the Qinshui coalfield show that:the influence depths of additional stress in the goaf ground caused by high-speed railroad varying from large to small are train meet,single train and no train;the additional stress influence depth in the goaf ground of embankment section is greater than that of road graben sec-tion;the decay law of additional stress along depth is the same in embankment section and road cut-ting section in the goaf ground;with the increase of embankment height,the additional stress influ-ence depth increases almost linearly.