川藏公路溢流型涎流冰影响因素试验与分析  

Experimental Study on Influencing Factors of Extruded Ice in Sichuan-Tibet Highway

作　　者：罗为国 LUO Weiguo(Guangzhou Branch of China Huaxi Engineering Design and Construction Co.,Ltd.,Guangzhou Guangdong 510061,China)

机构地区：[1]中国华西工程设计建设有限公司广州分公司,广东广州510061

出　　处：《广东公路交通》2023年第5期1-7,17,共8页Guangdong Highway Communications

摘　　要：涎流冰是川藏交通廊道区普遍存在的一种地质灾害。通过卫星图像判识和现场调查表明,川藏公路涎流冰以坡面溢流型为主。通过室内模拟试验分析了地形、透水层厚度、含水层厚度及渗透性等对涎流冰形成的影响。试验分析表明,负温条件下当地下水出露或地下水浅埋(一般地下水位小于冻深)时涎流冰就会形成。负地形因利于地下水汇集而更易于形成涎流冰。涎流冰形成过程中,孔隙水压力的变化具有明显的阶段性。冻结过程中冻结层逐渐封闭为整体,孔隙水压力呈先线性增长、后增长速率逐渐变缓直至稳定。地下水位越深,冻结形成涎流冰的时间越长;孔隙水压力越大,间接说明涎流冰的形成与冻深有关。含水层渗透性越好,相同条件下形成涎流冰的时间越短,形成的涎流冰规模越大,地下水孔隙水压力越高。含水层厚度越大,涎流冰规模也越大,但地下水孔隙水压力相对降低。试验结果表明,负地形、地下水浅埋、含水层厚且渗透性好,是形成大规模涎流冰的有利条件。Extruded ice is a common geological disaster in Sichuan-Tibet Traffic Corridor Region.Through satellite image identification and field investigation,it has been shownthat the extruded ice in the Sichuan-Tibet Highway is mainly of slope-overflow type.The effects of topography,permeable layer thickness,aquifer thickness and permeability on the formation of extruded ice have been studied by indoor simulation experiments.The experimentresults haveshown that extruded ice will form when groundwater is exposed or buried shallow(generally the groundwater level is less than the freezing depth)under negative temperature conditions.Negative terrain is more conducive to the accumulation of groundwater and is more likely to form extruded ice.During the formation of extruded ice,the pore water pressure is changed in obvious stages.During the freezing process,the frozen layer is gradually closed as a whole,and the pore water pressure increases linearly at first,and then the growth rate gradually slows down until the pore water pressure is stable.By increasing the thickness of permeable layer,the influence of groundwater level on the formation of extruded ice has been studied.It has shown that the deeper the groundwater level is,the longer the time of freezing and forming extruded ice is,and the greater the pore water pressure.It hasindirectly shown that the formation of extruded ice is related to the freezing depth.If the buried depth of groundwater is less than the maximum freezing depth in the region,extruded ice is easy to form.The better the permeability of the aquifer,the shorter time to form extruded ice under the same conditions,the larger the scale of extruded ice,and the higher the pore water pressure of groundwater.The larger the thickness of the aquifer,the larger the scale of extruded ice,but the pore water pressure of groundwater is relatively reduced.The comprehensive experimentresults have shown that negative terrain,shallow groundwater,thick aquifer and good permeability are the favorable conditions for the form

关 键 词：涎流冰 公路 模型试验 现场调查 孔隙水压力 含水层 

分 类 号：U213.1[交通运输工程—道路与铁道工程]