温度变化对粗粒硫酸盐渍土路基变形影响分析  

Influence of Temperature Change on Deformation of Coarse-grained Sulfate Saline Soil Subgrade

作　　者：杨晓华[1] 刘伟[1,2] 张莎莎 肖飞[1] 陈伟志[3] YANG Xiao-hua;LIU Wei;ZHANG Sha-sha;XIAO Fei;CHEN Wei-zhi(School of Highway,Chang'an University,Xi'an 710064,Shaanxi,China;Construction Engineering Department,Taiyuan University,Taiyuan 030009,Shanxi,China;China Railway Eryuan Engineering Group Co.Ltd.,Chengdu 610031,Sichuan,China)

机构地区：[1]长安大学公路学院,陕西西安710064 [2]太原学院建筑工程系,山西太原030009 [3]中国中铁二院工程集团有限责任公司,四川成都610031

出　　处：《中国公路学报》2020年第3期64-72,共9页China Journal of Highway and Transport

基　　金：国家自然科学基金项目(51209006);新疆维吾尔自治区交通运输厅科技项目(2014-08);中国中铁重大科研项目(2017-重大-11-04);中央高校基本科研业务费专项资金项目(300102219219)。

摘　　要：粗粒硫酸盐渍土路基在环境温度变化下易出现盐胀、沉陷等变形问题,其对路基正常使用造成的影响不容忽视。针对此问题,依托伊朗德黑兰-库姆-伊斯法罕高速铁路项目,在施工现场选取试验段,开展路基温度、水分的长期监测,分析路基温度和含水率随时间的变化规律。在此基础上,利用自主设计的温度变化试验装置,采用现场路基填料,开展室内温度变化循环试验,对粗粒硫酸盐渍土的变形特性进行研究。结果表明:监测期间,试验段路基温度的敏感深度为0.22m,深度为1.0m以内的路基含水率变化较大;在9个周期的试验过程中,试样深度在20cm范围内的温度和含水率随时间的变化更为显著,且随着试验温度的变化,试样温度的变化存在一定的滞后性;含盐量为1.5%的土样在第1,2次温度变化循环试验中表现为盐-冻胀变形,其最大盐-冻胀变形量为0.128mm,而含盐量为3%的土样在前6次循环试验中均表现为盐-冻胀变形,其最大盐-冻胀变形量为0.232mm;由于受到温度、冰盐相变、含盐量、土颗粒组成、试验周期等多重因素的影响,9个试验周期后,不同含盐量的试样最终均呈现沉陷变形,其中,含盐量为1.5%试样的最终沉陷变形量为0.585mm,是含盐量为3%试样最终沉陷变形的5.42倍。该研究结果可为相关工程提供一定的技术参考和借鉴。Coarse-grained sulfate soil roadbeds are prone to excessive deformation problems,such as salt expansion and subsidence owing to changes in ambient temperature,and the impact on normal use of the roadbed cannot be ignored.In view of these problems,a test section was selected at the construction site of the Tehran-Qom-Isfahan high-speed railway project in Iran,and long-term monitoring of the roadbed temperature and moisture content was carried out.The variation of temperature and moisture content of the roadbed with time was analyzed.Based on this,a self-designed temperature change test device and field roadbed filling were used to conduct indoor temperature change cycle model tests to study the deformation characteristics of coarsegrained sulfate saline soil.The results show that during the monitoring period,the sensitive depth of the subgrade temperature in the field test is 0.22 m,and the moisture content of the subgrade within the depth of 1.0 mvaries greatly.During the nine-cycle test,the temperature and moisture content of the sample depth in the range of 20 cm become more significant over time.However,with a change of the test temperature,there is a certain hysteresis in the change of sample temperature.The soil sample with 1.5%salt content shows salt expansion deformation and frost heave deformation in the first and second temperature change cycle tests,with a maximum deformation of 0.128 mm.The soil sample with 3%salt content exhibits such deformation in the first six cycles of the test,with a maximum deformation of 0.232 mm.Due to the influence of multiple factors such as temperature,ice-salt transformation,salt content,soil particle composition,and test cycle,specimens with different salt content eventually experience subsidence deformation after nine test cycles.The subsidence deformation of the sample with 1.5%salt content is 0.585 mm,which is 5.42 times the final subsidence deformation of the soil with 3%salt content.The research results can provide certain technical references for related projects.

关 键 词：道路工程 粗粒硫酸盐渍土 温度变化循环试验 变形 

分 类 号：U416.1[交通运输工程—道路与铁道工程]