为分析青藏铁路路基高程不规则变形,基于Box-Jenkins建模方法,确定时间序列模型阶数,根据AIC(Akaike information criterion)准则,选取适合的时间序列模型,最后给出批量预测全部路基测点高程的算法步骤。通过建立高程-时间响应模型的方...为分析青藏铁路路基高程不规则变形,基于Box-Jenkins建模方法,确定时间序列模型阶数,根据AIC(Akaike information criterion)准则,选取适合的时间序列模型,最后给出批量预测全部路基测点高程的算法步骤。通过建立高程-时间响应模型的方法,研究了青藏铁路路基高程随时间变形规律问题。以2010—2018年每月青藏铁路K1425+050处左侧路基高程数据为例,建立了ARIMA(2,1,1)模型,并以2019年数据作为验证集。结果表明:模型通过了模型适应性检验,证明了模型的有效性和准确性;总结了青藏铁路沿线各测点至2023年12月预测值中可能出现重大变形以及测点左右两侧路基高程差值出现较大差值的10个危险点;在测点K1476+600附近,路基两侧出现明显长距离的差异。可见本模型能准确预测青藏铁路路基高程的变化,对于工程养护维修具有一定借鉴意义。展开更多
The main factors that influence the temperature field of frozen subgrade were analyzed.The experimental equipment for simulating frozen subgrade was built up,and the declining regulating tubes were placed at the foot ...The main factors that influence the temperature field of frozen subgrade were analyzed.The experimental equipment for simulating frozen subgrade was built up,and the declining regulating tubes were placed at the foot of the embankment. By means of this equipment two simulating experiments of controlling temperature filed of frozen sub- grade were carried out in the laboratory.One method is to collect natural cold energy,and the other one is to collect natural cold energy ccompanied by artificial refrigeration simultaneously.The result indicates that the latter is an ef- fective method for maintaining the stability of the frozen subgrade.展开更多
Ten years of ground temperature data(2003–2013) indicate that the long-term thermal regimes within embankments of the Qinghai-Tibet Railway(QTR) vary significantly with different embankment structures. Obvious asymme...Ten years of ground temperature data(2003–2013) indicate that the long-term thermal regimes within embankments of the Qinghai-Tibet Railway(QTR) vary significantly with different embankment structures. Obvious asymmetries exist in the ground temperature fields within the traditional embankment(TE) and the crushed-rock basement embankment(CRBE). Measurements indicate that the TE and CRBE are not conducive to maintaining thermal stability. In contrast, the ground temperature fields of both the crushed-rock sloped embankment(CRSE) and the U-shaped crushed-rock embankment(UCRE) were symmetrical. However, the UCRE gave better thermal stability than the CRSE because slow warming of deep permafrost was observed under the CRSE. Therefore, the UCRE has the best long-term effect of decreasing ground temperature and improving the symmetry of the temperature field. More generally, it is concluded that construction using the cooling-roadbed principle meets the design requirements for long-term stability of the railway and for train transport speeds of 100 km h?1. However, temperature differences between the two shoulders, which exist in all embankments shoulders, may cause potential uneven settlement and might require maintenance.展开更多
文摘为分析青藏铁路路基高程不规则变形,基于Box-Jenkins建模方法,确定时间序列模型阶数,根据AIC(Akaike information criterion)准则,选取适合的时间序列模型,最后给出批量预测全部路基测点高程的算法步骤。通过建立高程-时间响应模型的方法,研究了青藏铁路路基高程随时间变形规律问题。以2010—2018年每月青藏铁路K1425+050处左侧路基高程数据为例,建立了ARIMA(2,1,1)模型,并以2019年数据作为验证集。结果表明:模型通过了模型适应性检验,证明了模型的有效性和准确性;总结了青藏铁路沿线各测点至2023年12月预测值中可能出现重大变形以及测点左右两侧路基高程差值出现较大差值的10个危险点;在测点K1476+600附近,路基两侧出现明显长距离的差异。可见本模型能准确预测青藏铁路路基高程的变化,对于工程养护维修具有一定借鉴意义。
基金Projects 2002CB412704 supported by the National Key Basic Research and Development Foundation of the Ministry of Sciences and Technology of China KZCX1-SW-04 supported by the Knowledge Innovation Program of the Chinese Academy of SciencesSKLFSE200304
文摘The main factors that influence the temperature field of frozen subgrade were analyzed.The experimental equipment for simulating frozen subgrade was built up,and the declining regulating tubes were placed at the foot of the embankment. By means of this equipment two simulating experiments of controlling temperature filed of frozen sub- grade were carried out in the laboratory.One method is to collect natural cold energy,and the other one is to collect natural cold energy ccompanied by artificial refrigeration simultaneously.The result indicates that the latter is an ef- fective method for maintaining the stability of the frozen subgrade.
基金supported by the National Basic Research Program of China(Grant No.2012CB026101)the Western Project Program of the Chinese Academy of Sciences(Grant No.KZCX2-XB3-19)+1 种基金the Foundation for Innovative Research Groups of the National Natural Science Foundation of China(Grant No.41121061)the National Sci-Tech Support Plan(Grant No.2014BAG05B05)
文摘Ten years of ground temperature data(2003–2013) indicate that the long-term thermal regimes within embankments of the Qinghai-Tibet Railway(QTR) vary significantly with different embankment structures. Obvious asymmetries exist in the ground temperature fields within the traditional embankment(TE) and the crushed-rock basement embankment(CRBE). Measurements indicate that the TE and CRBE are not conducive to maintaining thermal stability. In contrast, the ground temperature fields of both the crushed-rock sloped embankment(CRSE) and the U-shaped crushed-rock embankment(UCRE) were symmetrical. However, the UCRE gave better thermal stability than the CRSE because slow warming of deep permafrost was observed under the CRSE. Therefore, the UCRE has the best long-term effect of decreasing ground temperature and improving the symmetry of the temperature field. More generally, it is concluded that construction using the cooling-roadbed principle meets the design requirements for long-term stability of the railway and for train transport speeds of 100 km h?1. However, temperature differences between the two shoulders, which exist in all embankments shoulders, may cause potential uneven settlement and might require maintenance.
