西北寒冷地区道路冻胀翻浆防治技术研究

发布时间：2018-03-13 19:17

本文选题：冻土　切入点：冻胀翻浆　出处：《兰州交通大学》2015年硕士论文　论文类型：学位论文

【摘要】：甘肃省地处西北,处于冬季季风性气候区、西北干旱区及青藏高寒气候区的交汇地带,冬季严寒,道路冻胀翻浆病害普遍,严重影响了我省的道路工程建设与发展。甘肃省春融期间大量的道路工程会发生季节性翻浆病害,影响行车安全及产生道路畅通问题,在甘南、合作、临夏、陇南、定西及乌鞘岭等地尤其严重,即使是新修的道路工程也经常有路基冻胀翻浆病害发生。甘肃省每年都要投入大量的人力、物力和财力到道路翻浆病害整治中去。在季节冻土地区,伴随着土中水的冻结和融化,发生着一系列奇异而独特的冻土现象,如随着大气温度的下降,土体温度降到土中孔隙水结晶点时,土体便发生冻结,出现冰晶体,导致土体发生冻胀。到了春季,随着气温的上升,冻结后的土体从上层开始融化,但冻土层的下层尚未消融,水分无法下渗,使土体含水量增大,导致强度降低。一旦土体中冰侵入体消融成水,而土体又未能完全排水固结,在上部荷载作用下产生的孔隙水压力大到足以使路基土体发生流动时,就会以泥浆形式向上部粗颗粒运动及从路面裂缝中冒出,使上部结构发生沉陷变形及道路翻浆冒泥等现象。翻浆的出现极大地降低了路基的稳定性和增加了道路变形。现在防治路基冻胀翻浆较为常用的措施是换填冻胀性较小的粗颗粒土。但是,现有室内外试验和实际工程均已证明:通过换填粗颗粒土的方法只能减少冻胀,不能消除水分迁移。在反复冻融的情况下,路基中发生竖向及侧向水分迁移和积聚,路基中仍然会有较大的含水量,在冻融作用及上部荷载作用下仍有翻浆现象的发生。现在普遍使用的路基结构不能从根本上消除路基冻胀翻浆病害的发生,迫切需要寻求新的路基结构型式,改变路基中的水分迁移条件,防止路基冻胀翻浆的发生。本文通过理论分析及室内试验,研究季节冻土区道路翻浆破坏机理及影响因素,通过室内模型试验研究季节冻土区路基内的水分迁移规律及路基变形规律,提出防止道路翻浆破坏的新型双向防隔水路基结构型式。对季节冻土区道路工程的建设、运营及维护有着重要的现实意义。
[Abstract]:Gansu Province is located in the northwest, is located in the winter monsoon climate area, the northwest arid area and the Qinghai-Tibet alpine climate area intersection area, the winter cold, the road frost heaving and mudding disease is widespread, It has seriously affected the construction and development of road engineering in our province. A large number of road projects in Gansu Province during the spring melt period will have seasonal mudding disease, which will affect the safety of driving and the problems of road unblocked, in Gannan, cooperation, Linxia, Longnan, Dingxi and Wushaoling are especially serious. Even new road projects often suffer from roadbed frost heaving and slurping. Gansu province spends a lot of manpower every year. Material and financial resources go to the treatment of road ploughing disease. In seasonally frozen soil areas, with the freezing and melting of water in the soil, a series of strange and unique frozen soil phenomena occur, such as as the temperature of the atmosphere drops. When the soil temperature drops to the crystallization point of pore water in the soil, the soil is frozen and ice crystals appear, which results in the frost heaving of the soil. In spring, the frozen soil begins to melt from the upper layer as the temperature rises. However, the lower layer of the frozen soil has not been ablated, and the water can not be infiltrated, which increases the water content of the soil and leads to the decrease of the strength. Once the ice intrusion in the soil melts into water and the soil fails to be completely drained and consolidated, When the pore water pressure under the upper load is large enough to cause the subgrade soil to flow, it will move to the upper thick particles in the form of mud and emerge from the cracks in the pavement. Causes the superstructure to take place the subsidence deformation and the road muddy and so on phenomenon. The appearance of the slurry greatly reduces the roadbed stability and increases the road deformation.Now the common measure to prevent the roadbed frozen-heaving is to replace the fill frost-heave. Coarse grained soil with less property. However, The existing indoor and outdoor tests and practical projects have proved that the method of replacing coarse granular soil can only reduce frost heaving and can not eliminate water migration. In the case of repeated freezing and thawing, vertical and lateral water migration and accumulation occur in the roadbed. There is still a large water content in the roadbed, and there is still the phenomenon of overturning under the action of freezing and thawing and the upper load. The commonly used subgrade structure can not fundamentally eliminate the frost heaving and overturning disease of the roadbed. It is urgent to seek new subgrade structure form, change the water transfer condition in subgrade, prevent the frost-heaving and churning of roadbed. Through theoretical analysis and laboratory test, this paper studies the mechanism and influencing factors of road churn failure in seasonal frozen soil area. Through indoor model test, the law of water migration and subgrade deformation in the subgrade of seasonal frozen soil region is studied, and a new type of bidirectional waterproof subgrade structure is proposed to prevent the road from being damaged by slurry. The construction of road engineering in seasonal frozen soil region is studied. Operation and maintenance have important practical significance.
【学位授予单位】：兰州交通大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U418.53

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