首页|下蜀土降雨入渗光纤感测及渗透系数估算研究

下蜀土降雨入渗光纤感测及渗透系数估算研究

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下蜀土中裂隙较为发育,在降雨时入渗能力强,因此容易诱发浅层滑坡等灾害.为了研究下蜀土的降雨入渗特征,本文采用主动加热光纤光栅(AH-FBG)法开展了地基土水分分布及其动态变化的原位监测研究.基于监测数据,掌握了冬季和夏季土体体积含水率的时空分布特征,并计算得到降雨事件的降雨入渗量及入渗补给系数.在此基础上,通过稳态法计算获取了原位下蜀土的非饱和渗透系数,并与间接法估算值进行比较.结果表明:将AH-FBG法应用于下蜀土含水率的原位监测具有可行性,其中5 cm深度的均方根误差较大,为0.0252 m3·m-3,主要受到浅层土体和空气的热量交换作用以及土体裂隙的影响,其余深度均不超过0.01 m3·m-3.原位监测系统对降雨入渗和蒸发作用引起的含水率变化均具有良好的响应.无论是冬季还是夏季,由稳态法计算得到的原位非饱和渗透系数均大于间接法估算值,表明下蜀土中的裂隙为降雨入渗提供了优先渗流通道.
FIBER OPTIC MONITORING OF RAINFALL INFILTRATION IN XIASHU SOIL AND PERMEABILITY COEFFICIENT ESTIMATION
Cracks are frequently observed in Xiashu soil,which have great infiltration capacity during rainfall and easily induce shallow landslides and other geohazards.In order to study the characteristics of rainfall infiltration of Xiashu soil,in this paper,the actively heated fiber Bragg grating(AH-FBG)method was used to perform field mo-nitoring of moisture distributions and their variations in in-situ soil.Based on the monitoring results,the spatial and temporal distribution characteristics of volumetric water content in winter and summer were obtained,and the rain-fall infiltration and recharge coefficient of rainfall events were calculated.On this basis,the permeability coefficients of Xiahu soil were estimated using the steady-state method,which were compared with those measured by the indi-rect method.The results show that the application of AH-FBG based in-situ monitoring of moisture in Xiashu soil is feasible.The root mean square error of 5 cm depth is larger and 0.0252 m3·m-3.It is mainly affected by the heat exchange between the shallow soil and the air,as well as the soil cracks.The errors for other depths are not more than 0.01 m3·m-3.The in-situ monitoring system has good responses to the change in water contents caused by rainfall infiltration and evaporation.Both in winter and summer,the in-situ unsaturated permeability coefficients calculated by the steady-state method are larger than those estimated by the indirect method,which indicates that the cracks in Xiashu soil provide a preferential seepage channel for rainfall infiltration.

Xiashu soilActively heated fiber Bragg grating(AH-FBG)Water migrationVolumetric water con-tentUnsaturated permeability coefficientRainfall infiltration

李杰、朱鸿鹄、吴冰、刘喜凤、王家琛、曹鼎峰、施斌

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南京大学地球科学与工程学院,南京 210023,中国

南京大学(苏州)高新技术研究院,苏州 215123,中国

中国长江三峡集团雄安分公司,雄安 071700,中国

中山大学土木工程学院,广州 510275,中国

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下蜀土 主动加热光纤光栅 水分迁移 体积含水率 非饱和渗透系数 降雨入渗

国家自然科学基金项目江苏省自然科学基金项目国家重点研发计划

42225702BK202110862023YFF1303501

2024

10.13544/j.cnki.jeg.2022-0092

工程地质学报
中国科学院地质与地球物理研究所

工程地质学报

CSTPCD北大核心
影响因子：1.215
ISSN：1004-9665
年,卷(期)：2024.32(2)
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