ISSN 1000-3665 CN 11-2202/P
    闫星光,卢泽昌,张进才,等. 雄安新区东北部地面沉降成因探讨[J]. 水文地质工程地质,2023,50(4): 173-184. DOI: 10.16030/j.cnki.issn.1000-3665.202207019
    引用本文: 闫星光,卢泽昌,张进才,等. 雄安新区东北部地面沉降成因探讨[J]. 水文地质工程地质,2023,50(4): 173-184. DOI: 10.16030/j.cnki.issn.1000-3665.202207019
    YAN Xingguang, LU Zechang, ZHANG Jincai, et al. A discussion of the cause of land subsidence in the northeast of the Xiongan New Area[J]. Hydrogeology & Engineering Geology, 2023, 50(4): 173-184. DOI: 10.16030/j.cnki.issn.1000-3665.202207019
    Citation: YAN Xingguang, LU Zechang, ZHANG Jincai, et al. A discussion of the cause of land subsidence in the northeast of the Xiongan New Area[J]. Hydrogeology & Engineering Geology, 2023, 50(4): 173-184. DOI: 10.16030/j.cnki.issn.1000-3665.202207019

    雄安新区东北部地面沉降成因探讨

    A discussion of the cause of land subsidence in the northeast of the Xiongan New Area

    • 摘要: 为深入研究雄安新区东北部地面沉降主控因素,以大营镇分层标组为研究对象,利用常规土工试验、高压固结试验与分层沉降观测数据,结合前人研究成果对地面沉降成因进行探讨。结果表明:大营镇分层标组G1孔内第四系松散层总厚度412 m,其中浅部地层(第I、II含水组)厚度约170 m,黏性土占比66.4%~80.2%,结构松散,砂黏互层交替频繁,释水条件较好。浅部黏性土颗粒较细、分选性好、孔隙度大,液性指数多大于0.25,呈软塑、可塑态,自重压缩系数为0.03~0.43,均值0.08,与深部相比压缩性较强。浅部黏性土层以欠固结、正常固结夹欠固结状态为主,0~90 m超固结比均值为0.55,90~280 m超固结比均值为0.89,易于发生塑性变形,形成永久性沉降。雄安新区主要开采浅层地下水,地面沉降与地下水关系密切。2020年12月—2021年12月,大营镇分层标组监测结果显示,第四系松散层总沉降量为61 mm。其中,5~160 m第四系松散层沉降贡献量最大,为42 mm,表现为塑性形变特征;160~415 m第四系地层沉降贡献量小,为19 mm,表现为黏弹塑性形变特征。过量开采浅层地下水引起浅部固结程度低、压缩性高的黏性土层发生塑性变形是发生严重沉降的主要原因。

       

      Abstract: In order to deeply study the main controlling factors of land subsidence in the northeast of the Xiongan New Area, the layered monitoring points of Daying Town are taken as the research object, and the causes of land subsidence are discussed based on the conventional soil test, high pressure consolidation test and layered settlement observation data combined with previous research results. The results show that the total thickness of the Quaternary loose layer in the layered monitoring points of G1 hole in Daying Town is 412 m, and the thickness of the shallow layer is 170 m. The viscous soil accounts for 66.4%−80.2%. The structure is loose and the sand-clay interlayer alternates frequently, and the water release condition is good. The shallow viscous soil has finer particles, good sortability, large porosity, and more than 0.25 liquid index, showing a soft plastic and plasticable state. The dead weight compression coefficient ranges from 0.03 to 0.43, with an average value of 0.07. Compared with the deep soil, the shallow viscous soil is of stronger compressibility. The shallow cohesive soil layer is dominated by underconsolidation, normal consolidation and underconsolidation. The average OCR of a depth of 0−90 m is 0.55, and that of 90-280 m is 0.89. Plastic deformation and permanent settlement are easy to occur. Xiongan New Area mainly exploits shallow groundwater, which is closely related to land subsidence. From December 2020 to December 2021, the monitoring results of the layered monitoring points of Daying Town show that the total settlement of the Quaternary loose layer is 61 mm. Among them, the subsidence contribution of the shallow Quaternary unconsolidated layer at a depth of 5−160 m is the largest, which is 42 mm, showing the characteristics of plastic deformation. The subsidence contribution of the deep Quaternary strata at 160−415 m is 19 mm, which shows the characteristics of viscoelastic-plastic deformation. The plastic deformation of cohesive soil layer with low consolidation and high compressibility caused by the excessive exploitation of shallow groundwater is the main cause of serious settlement.

       

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