青藏铁路多年冻土区路堑边坡病害特征及防治措施分析
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摘要
青藏铁路格拉段多年冻土区共有路堑边坡78处,长约15.6 km,其稳定性直接关系到线路安全运营。根据现场调查,分析其稳定性状况、病害形式、影响因素及机理,讨论防治措施的合理性。结果表明:先后有15处出现病害,其中4处失稳,病害问题值得重视;病害形式包括坡面冲刷、纵向裂缝、防护结构破坏、滑塌、坡脚鼓胀等;病害位置以边坡上侧为主,而非阳坡侧,堑顶是最薄弱的部位,发育过程表现为周期性和波动性的恶化;地表水和冻结层上水的热侵蚀及活动层冻融作用是病害的主要原因,病害机理包括地表水冲刷、滞水冻胀和冻融循环;经过运营期检验,无防护的坡面容易冲刷变形,封闭式锚喷混凝土面容易滞水冻胀破裂,轻型、柔性的骨架护坡和L型挡墙防护效果较好。
There are 78 cutting slopes in permafrost regions along Qinghai- Tibet Railway,with the length of about 15. 6 km,and the stability of the slopes is directly related to the safe operation of the line. This paper analyzes stability conditions,forms of defects,influencing factors and mechanisms of the slopes based on field surveys. The rationality of the protective measures is also discussed. The results show that the number of defected cutting slopes comes to 15,4 of which lost their stability. The defects are characterized by surface scouring,longitudinal cracks,destruction of protective structures,collapse and toe swollen. The defects are mainly located at the upper part of slopes,rather than the sunny side,and the top of the cutting is the weakest part. The development is characteristics of periodic process and fluctuated deterioration. Thermal erosion of external water and suprapermafrost water,freeze-thaw action of active layer are the main causes of the defects. Defect mechanisms include erosion of external water,frozen expansion of stagnant water and freeze-thaw circulation. The inspection in the operation period shows that slopes without protection are prone to scouring and deformation,closed anchor-spray concretes are likely to be ruptured by freezing expansion force of stagnant water,light and flexible frame structure and L-type retaining wall are effective in protection.
There are 78 cutting slopes in permafrost regions along Qinghai- Tibet Railway,with the length of about 15. 6 km,and the stability of the slopes is directly related to the safe operation of the line. This paper analyzes stability conditions,forms of defects,influencing factors and mechanisms of the slopes based on field surveys. The rationality of the protective measures is also discussed. The results show that the number of defected cutting slopes comes to 15,4 of which lost their stability. The defects are characterized by surface scouring,longitudinal cracks,destruction of protective structures,collapse and toe swollen. The defects are mainly located at the upper part of slopes,rather than the sunny side,and the top of the cutting is the weakest part. The development is characteristics of periodic process and fluctuated deterioration. Thermal erosion of external water and suprapermafrost water,freeze-thaw action of active layer are the main causes of the defects. Defect mechanisms include erosion of external water,frozen expansion of stagnant water and freeze-thaw circulation. The inspection in the operation period shows that slopes without protection are prone to scouring and deformation,closed anchor-spray concretes are likely to be ruptured by freezing expansion force of stagnant water,light and flexible frame structure and L-type retaining wall are effective in protection.
引文
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[11]温智,盛煌,马巍,等.多年冻土区路堑边坡防护试验研究[J].铁道工程学报,2009(7):1-5.
[12]魏智,金会军,张建明,等.主动和被动的冻土地温控制方法和技术[J].铁道工程学报,2008(11):20-26.
[13]魏静,许兆义,葛建军,等.青藏铁路路基预制拼装式骨架护坡试验分析[J].岩石力学与工程学报,2006,25(2):329-333.
[14]刘娟.青藏铁路楚玛尔河地区复合路基地温状况分析[J].铁道标准设计,2013(12):40-42.
[15]熊治文,廖小平,朱本珍,等.多年冻土地区路堑边坡病害及其整治原则[J].铁道工程学报,2010(7):6-10.
[16]梁波,葛建军.青藏铁路多年冻土区L型挡土墙综合特性的试验研究[J].岩土工程学报,2011,33(增1):59-64.
[17]刘桂香,孙常新,梁波.青藏铁路多年冻土区加筋土特性试验研究[J].路基工程,2008(6):133-135.
[18]王申平.柔性护坡在青藏铁路多年冻土区路基的试验[J].路基工程,2008(4):76-77.
[2]周有禄,熊治文,李天宝,等.青藏铁路多年冻土区桥头路基病害成因分析及整治措施研究[J].铁道标准设计,2013(10):40-44.
[3]熊治文,廖小平,徐兵魁,等.青藏铁路多年冻土边坡与斜坡路基研究综述[J].铁道学报,2010,32(4):102-107.
[4]刘建坤,童长江,房建宏.寒区岩土工程引论[M].北京:中国铁道出版社,2005.
[5]刘争平,王连俊.青藏铁路北麓河路堑变形浅析[J].西部探矿工程,2005(4):194-196.
[6]中铁西北科学研究院.运营条件下青藏铁路多年冻土区路基病害调查与整治措施研究[R].兰州:中铁西北科学研究院,2011.
[7]王天亮,卜建清,王扬,等.多次冻融条件下土体的融沉性质研究[J].岩土工程学报,2014,36(4):625-632.
[8]常丹,刘建坤,李旭,等.冻融循环对青藏粉砂土力学性质影响的试验研究[J].岩石力学与工程学报,2014,33(7):1496-1502.
[9]沈宇鹏,许兆义,王连俊.青藏铁路路基中正融土斜坡稳定性分析[J].中国安全科学学报,2005,15(7):97-100.
[10]王永顺.青藏铁路多年冻土区高含冰量路堑边坡挡护结构的探讨[J].铁道标准设计,2008(5):19-22.
[11]温智,盛煌,马巍,等.多年冻土区路堑边坡防护试验研究[J].铁道工程学报,2009(7):1-5.
[12]魏智,金会军,张建明,等.主动和被动的冻土地温控制方法和技术[J].铁道工程学报,2008(11):20-26.
[13]魏静,许兆义,葛建军,等.青藏铁路路基预制拼装式骨架护坡试验分析[J].岩石力学与工程学报,2006,25(2):329-333.
[14]刘娟.青藏铁路楚玛尔河地区复合路基地温状况分析[J].铁道标准设计,2013(12):40-42.
[15]熊治文,廖小平,朱本珍,等.多年冻土地区路堑边坡病害及其整治原则[J].铁道工程学报,2010(7):6-10.
[16]梁波,葛建军.青藏铁路多年冻土区L型挡土墙综合特性的试验研究[J].岩土工程学报,2011,33(增1):59-64.
[17]刘桂香,孙常新,梁波.青藏铁路多年冻土区加筋土特性试验研究[J].路基工程,2008(6):133-135.
[18]王申平.柔性护坡在青藏铁路多年冻土区路基的试验[J].路基工程,2008(4):76-77.