摘要
近10年来,铁路建设飞速发展的过程中,沿线排水系统的结晶失效给路基基床的稳定性带来了极大的安全问题。鉴于此,2013—2016年间在法国高速铁路Chauconin路段上进行了地质钻探、水化学监测、水力计算和数值模拟来分析排水系统结晶的成因和土工影响。结果表明:在同一地质条件下,U型槽和明沟未监测到结晶,而HPED管周围的表层填土的渗透系数比设计值大,地表水渗流过程中溶解该土层的石膏和石灰石组分(含量超过85%质量比),过饱和(Ω高达270)在HPED管中产生方解石结晶;虽然HPED管和U型槽属于同一湍流范围,但后者冲刷流速是前者的2~3倍,不利于结晶;在同一HPED管中,结晶变化率与水深变化率一致,糙率和倾度对其影响较小(<3%),防治设计应以水深控制为主。研究结论可为我国铁路沿线排水系统结晶问题的防治提供设计及工程参数。
With the rapid development of China’s railway in the past ten years,the clogging of drainage facility along the railway has caused a great potential safety hazard to the stability of track foundation.In view of this problem,the study centered on the current insitu calcite clogging situation,hydrochemical and geotechnical causes of clogging produced in two kinds of commonly used railway infiltration trenches,such as U-groove and HPED pipe,through geological drilling,pipeline endoscope,hydraulic calculation,hydrochemical monitoring and simulation.The data was collected from 2013 to 2016 at the site of Chauconin located on the No.6 high-speed rail line in France.The analysis results show that under the same geological conditions,the calcite precipitates inside the HPED pipe instead of the U-groove and open trench.The hydrochemical causes of the calcite precipitated inside the HPED pipe are that a large amount of calcium and carbon sources(more than 85%mass ratio)contained in the surrounding filling materials of the subballast layer and capping layer,as well as larger insitu permeability than its design value cause the surface water to dissolve the limestone and gypsum components in the process of seepage inside the fill layer,which results in the supersaturation(Ωup to 270),and precipitation inside the HPED pipe.Additionally,although both the HPED pipe and the U-groove are not fully filled,the flow inside both is within the same turbulent range.However,the flow velocity in the U-groove is 2~3 times of that in the HPED pipe,too high to cause calcite precipitation.Furthermore,in the same HPED pipe,the variation ratio of calcite precipitation in each manhole is consistent with the variation ratio of water depth.Whereas,the roughness coefficient and the pipe inclination have less influence on the calcite precipitation(<3%).Based on the above results,in order to prevent the calcite precipitation,the U-groove is recommended instead of HPED pipe to be applied along the new railway line with a deeper water depth.The research conclusion can provide design and engineering parameters for the prevention and treatment of precipitation problems in the drainage system along the railway in China.
作者
贾能
钱会
柴少波
高志华
刘钦
张旭东
JIA Neng;QIAN Hui;CHAI Shaobo;GAO Zhihua;LIU Qin;ZHANG Xudong(School of Civil Engineering,Chang’an University,Xi’an 710061,China;School of Water and Environment,Chang’an University,Xi’an 710061,China;IG,SNCF,Paris 93200,France)
出处
《铁道学报》
EI
CAS
CSCD
北大核心
2022年第8期166-177,共12页
Journal of the China Railway Society
基金
国家自然科学基金(41902277)
陕西省自然科学基金(2021-JQ232)
中央高校基本科研业务费(300102280106)。
