Wet winter pore pressures in railway embankments
Wet winter pore pressures in railway embankments
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DOI：
10.1680/geng.11.00106
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发表时间：
2013-02
期刊：
影响因子：
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通讯作者：
K. Briggs;J. Smethurst;W. Powrie;A. O'brien
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文献类型：
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作者：
K. Briggs;J. Smethurst;W. Powrie;A. O'brien
本文利用现场监测数据和数值模拟，论证了冬季极端潮湿天气对铁路粘土填筑路堤孔隙水压力的影响。在2000/2001年潮湿的冬天之后，对伦敦地铁有限公司网络的压力计读数进行了检查，并显示了堤防内静水孔隙水压力的发生，但也有许多读数低于此值。最大孔隙水压力与路堤地基土的渗透性之间存在相关性，高渗透性地基土（白垩或河流阶地沉积物）在上覆粘土路堤填筑物中提供下排水并保持低孔隙水压力。响应气候边界条件的瞬态水流的数值模拟支持这一结论，并已用于证明粘土填充和下伏地基渗透性对极端（100年1摄氏度）和中期（10年1摄氏度）冬季湿降雨期间瞬态孔隙水压力的影响。对于粘土路基，极端潮湿的冬季条件显著增加孔隙水压力，而对于渗透性地层下垫的堤坝，孔隙水压力对极端冬季降雨的敏感性较低。
This paper demonstrates the influence of extreme wet winter weather on pore water pressures within clay fill railway embankments, using field monitoring data and numerical modelling. Piezometer readings taken across the London Underground Ltd network following the wet winter of 2000/2001 were examined, and showed occurrences of hydrostatic pore water pressure within embankments but also many readings below this. A correlation was found between the maximum pore water pressures and the permeability of the embankment foundation soil, with high permeability foundation soils (of Chalk or river terrace deposits) providing underdrainage and maintaining low pore water pressures within the overlying clay embankment fill. Numerical modelling of transient water flow in response to a climate boundary condition supports this conclusion and has been used to demonstrate the influence of clay fill and underlying foundation permeability on transient pore water pressures during extreme (c. 1 in 100 year) and intermediate (c. 1 in 10 year) wet winter rainfall. For clay founded embankments, extreme wet winter conditions increased pore water pressures significantly compared with an intermediate winter, while for embankments underlain by a permeable stratum pore water pressures were less sensitive to the extreme winter rainfall.