开采扰动对铁路煤矸石路堤稳定性的影响

INFLUENCES OF MINING DISTURBANCE ON STABILITY FORRAILWAY EMBANKMENTS OF COAL GANGUE

通过三轴常规试验和改装后的侧向卸载加载三轴试验,研究受采动影响地基土的力学性能变化规律。基于模拟开采扰动地基土的力学特性和煤矸石路基填料在自然因素作用下物理力学参数衰变特性,研究在自然因素、软弱地基和采动影响共同作用下铁路煤矸石路堤稳定性演化规律。结果表明:受采动影响,地基土力学参数需进行折减,软土折减系数为0.9~1.0,普通土折减系数为0.6~0.7。整体和局部稳定分析表明:同一种水位高度,正常地基的煤矸石路堤在填筑施工结束后安全系数最大,而受采动影响的软弱地基的煤矸石路堤安全系数急剧降低。同一种地基条件,水位越高,安全系数越小。受采动影响的软弱地基上的路堤,受风化和降雨共同影响,安全系数较小,在水位高5 m时其稳定性不满足TB 10035—2018《铁路特殊路基设计规范》的要求,需要对采动区铁路路基进行加固设计。

The conventional triaxial test and the improved triaxial test are mainly used to study change laws of mechanical properties for soil in mining areas before and after being disturbed by mining. Based on the results of the triaxial tests subjected to lateral unloading or loading and the attenuation characteristics of physical and mechanical parameters for coal gangue under the coupling effects of natural factors,soft foundation and mining influence,the evolution laws of stability for railway embankments of coal gangue in subsidence zones affected by mining were researched. The results showed that under the influences of mining,the mechanical indexes of the foundation soil decreased,the reduction factor for soft soil was about 0. 9 to 1. 0,and the reduction factor was 0. 6 to 0. 7 for other soil. The overall and local stability analysis showed that the safety factors of embankments for coal gangue on conventional foundation conditions were the largest at the same groundwater level,the safety factors of embankments of coal gangue on soft foundation decreased sharply due to being mined. Under the same foundation conditions,the higher the level of groundwater,the samller the safety factors of embankments,the stability to embankments of coal gangue on soft foundation affected by mining was lower when the groundwater level was higher than 5 m,the safety factors of embankments could not meet the Code for Design on special Railway Earth Structure TB 10035-2018.Therefore,under the coupling action of rainwater and weathering,embankments in the subsidence zone should be reinforced.