西安建筑科技大学学报(自然科学版)

超期服役粉细砂基坑变形时效性研究

(1.西安理工大学西北旱区生态水利国家重点实验室,陕西西安 710048; 2.中铁第一勘察设计院集团有限公司,陕西西安 710043; 3.陕西建工第九建设集团有限公司,陕西榆林 719000)

Study on deformation timeliness of excessive service silt fine sand foundation pit

DANG Faning¹,WANG Haiyang²,GAO Cang³,XUE Baoxiang³,LI Yang³,LI Tao³

(1.State Key Laboratory of Eco-hydraulics in Northwest Arid Region, Xi'an University of Technology, Xi'an 710048, China; 2.China Railway First Survey and Design Institute Group Co., Ltd., Xi'an 710043, China; 3.Shaanxi Construction Ninth Construction Group Co., Ltd.,Shaanxi Yulin, 719000,China)

Keywords： fine sand foundation pit; creep model; creep parameters; extended service

DOI: 10.15986/j.1006-7930.2023.01.006

备注

摘要

全文

图/表

参考文献

粉细砂土地区深基坑变形具有显著的时间效应,该土的蠕变特性使护坡桩变形随时间的推移不断增大,支护不及时、施工停止时间过长等原因均可能导致基坑工程事故的发生.本文利用时间硬化蠕变模型反映基坑超期服役时的时间效应.通过粉细砂蠕变试验结果拟合蠕变模型参数,并将确定好的参数用于实际工程中的计算模拟,生成预测模型来计算基坑超期使用下的变形范围及趋势.结果表明:基坑土体变形随时间不断发展,水平变形速率两个月左右趋于平稳,坑外地表沉降速率在一个月左右趋于平稳,沉降值随着距坑边距离增大呈现先增大后减小的分布规律; 所建立的时间硬化蠕变模型能够合理模拟超期服役下粉细砂基坑的变形规律,预测基坑未来稳定性,可以为超期服役基坑工程进度安排及后期管理提供依据.

Deep foundation pit engineering in fine sand soil area has significant time effect. The creep property of the soil makes the deformation of slope protection pile increase with time, and the reasons such as untimely support and long construction stop time may lead to the occurrence of foundation pit engineering accidents. In this paper, the time hardening creep model is used to reflect the time effect of excavation in extended service. The creep model parameters are fitted by the results of the fine sand creep test, and the determined parameters are used in the calculation and simulation of the actual project. The creep parameters are adjusted by using the measured data through parameter inversion, and the prediction model is generated to calculate the deformation range and trend of the foundation pit under the overuse.Results: The soil deformation of the foundation pit develops with time, the horizontal deformation rate tends to be stable about two months, and the surface settlement rate outside the pit tends to be stable about a month. The settlement value increases first and then decreases with the increase of distance from the pit edge. The time-hardening creep model established in this paper can reasonably simulate the deformation law of the foundation pit of fine sand in extended service and predict the future stability of the foundation pit. The research can provide a basis for the schedule and management of the foundation pit in extended service.

引言
1 问题的提出
2 粉细砂土耦合蠕变模型
3 有限元模型建立
4 计算结果分析
5 实测数据与计算结果对比
6 结论

表1 土体强度参数表<br/>Tab.1 Soil mechanical parameters

表1 土体强度参数表
Tab.1 Soil mechanical parameters

表2 5个试样加载情况表<br/>Tab.2 Sample loading condition

表2 5个试样加载情况表
Tab.2 Sample loading condition

图1 90 kPa围压土样的三轴蠕变全过程试验曲线<br/>Fig.1 Triaxial creep test curve of soil samples under 90 kPa confining pressure

图1 90 kPa围压土样的三轴蠕变全过程试验曲线
Fig.1 Triaxial creep test curve of soil samples under 90 kPa confining pressure

图2 90 kPa围压下lnε～lnt曲线<br/>Fig.2 lnε～lnt curve under 90 kPa confining pressure

图2 90 kPa围压下lnε～lnt曲线
Fig.2 lnε～lnt curve under 90 kPa confining pressure

图3 不同时间下lnσ～lnε曲线<br/>Fig.3 curves at different times

图3 不同时间下lnσ～lnε曲线
Fig.3 curves at different times

图4 计算模型图<br/>Fig.4 Calculation model diagram

图4 计算模型图
Fig.4 Calculation model diagram

表3 护坡桩、冠梁设计信息表<br/>Tab.3 Design information sheet of slope protection pile and crown beam

表3 护坡桩、冠梁设计信息表
Tab.3 Design information sheet of slope protection pile and crown beam

表4 锚索设计参数表<br/>Tab.4 Anchor cable design parameters

表4 锚索设计参数表
Tab.4 Anchor cable design parameters

表5 支护结构弹性本构参数<br/>Tab.5 Elastic constitutive parameters of supporting structures

表5 支护结构弹性本构参数
Tab.5 Elastic constitutive parameters of supporting structures

表6 土体参数表<br/>Tab.6 Soil mechanical parameters

表6 土体参数表
Tab.6 Soil mechanical parameters

图5 网格划分后模型图<br/>Fig.5 Model diagram after meshing

图5 网格划分后模型图
Fig.5 Model diagram after meshing

图6 支护体系剖面图<br/>Fig.6 Section drawing of support system

图6 支护体系剖面图
Fig.6 Section drawing of support system

图7 特征点位置图<br/>Fig.7 Location of feature points

图7 特征点位置图
Fig.7 Location of feature points

图8 不同时间基坑土体水平位移云图(单位:m)<br/>Fig.8 Horizontal displacement cloud diagram of foundation pit soil at different times

图8 不同时间基坑土体水平位移云图(单位:m)
Fig.8 Horizontal displacement cloud diagram of foundation pit soil at different times

图9 各特征点水平蠕变变形随时间变化曲线<br/>Fig.9 Curve of horizontal creep deformation at each characteristic point with time

图9 各特征点水平蠕变变形随时间变化曲线
Fig.9 Curve of horizontal creep deformation at each characteristic point with time

图10 各特征点水平蠕变速率随时间变化曲线<br/>Fig.10 Curve of horizontal creep rate at each characteristic point with time

图10 各特征点水平蠕变速率随时间变化曲线
Fig.10 Curve of horizontal creep rate at each characteristic point with time

图11 护坡桩桩身水平位移变化曲线<br/>Fig.11 Curve of lateral displacement of slope protection pile

图11 护坡桩桩身水平位移变化曲线
Fig.11 Curve of lateral displacement of slope protection pile

表7 护坡桩变形统计<br/>Tab.7 Deformation statistics of slope protection pile

表7 护坡桩变形统计
Tab.7 Deformation statistics of slope protection pile

表8 护坡桩变形统计<br/>Tab.8 Deformation statistics of slope protection pile

表8 护坡桩变形统计
Tab.8 Deformation statistics of slope protection pile

图12 不同时间基坑土体竖向位移云图(单位:m)<br/>Fig.12 Cloud diagram of vertical displacement of foundation pit soil at different times

图12 不同时间基坑土体竖向位移云图(单位:m)
Fig.12 Cloud diagram of vertical displacement of foundation pit soil at different times

图13 基坑长边方向地表竖向位移变化曲线<br/>Fig.13 Curves of vertical surface displacement along the long side of foundation pit

图13 基坑长边方向地表竖向位移变化曲线
Fig.13 Curves of vertical surface displacement along the long side of foundation pit

图14 基坑短边方向地表竖向位移变化曲线<br/>Fig.14 Curves of vertical surface displacement along the short side of foundation pit

图14 基坑短边方向地表竖向位移变化曲线
Fig.14 Curves of vertical surface displacement along the short side of foundation pit

图15 各特征点竖向蠕变变形随时间变化曲线<br/>Fig.15 Curve of vertical creep deformation at each characteristic point with time

图15 各特征点竖向蠕变变形随时间变化曲线
Fig.15 Curve of vertical creep deformation at each characteristic point with time

图16 各特征点竖向蠕变速率随时间变化曲线<br/>Fig.16 Curves of vertical creep rate of each characteristic point with time

图16 各特征点竖向蠕变速率随时间变化曲线
Fig.16 Curves of vertical creep rate of each characteristic point with time

图17 竖向蠕变变形随时间变化曲线<br/>Fig.17 Curves of vertical creep deformation with time

图17 竖向蠕变变形随时间变化曲线
Fig.17 Curves of vertical creep deformation with time

图18 护坡桩侧向位移监测结果<br/>Fig.18 Monitoring results of displacement of slope protection pile

图18 护坡桩侧向位移监测结果
Fig.18 Monitoring results of displacement of slope protection pile

图19 实测值与计算值对比<br/>Fig.19 Comparison of measured and calculated values

图19 实测值与计算值对比
Fig.19 Comparison of measured and calculated values

[1] 孙晓涵. 西安地面沉降与砂土蠕变关系初探[D]. 西安:长安大学,2011.
[2]尹建华,顾凯,姜洪涛,等.砂土高压蠕变微观机理分析[J].高校地质学报,2018,24(1):116-121.
[3]王艳芳,蔡燕燕,蔡正银.饱和砂土蠕变特性实验[J].华侨大学学报(自然科学版),2017,38(1):31-37.
[4]杨伟涛,徐进,王少伟.含水层饱和砂土蠕变试验及流变模型辨识研究[J].烟台大学学报(自然科学与工程版),2020,33(3):354-359.
[5]赵文,韩健勇,李慎刚,等.砂土地层深基坑桩锚支护体系的受力与变形[J].东北大学学报(自然科学版),2015,36(4):576-580,595.
[6]门彬.超期服役基坑变形关键影响因素模拟分析[J].交通科学与工程,2020,36(3): 50-55.
[7]MA Fenghai. Research of deformation prediction method of soft soil deep foundation pit[J]. Journal of China Coal Society, 2008,14(4):3.
[8]包旭范. 软土地基超大型基坑变形控制方法研究[D].成都:西南交通大学,2008.
[9]张宇. 超期服役粉细砂基坑支护稳定性研究[D]. 西安:西安理工大学,2021.
[10]杨瑞意. 灰色GM-BP神经网络预测超期服役深基坑变形应用研究[D].广州:华南理工大学,2018.
[11]梅涛涛,王德咏,梁小丛.吹填砂性土长期沉降计算[J].水运工程, 2021(9):182-186.
[12]陈阳,赵文,贾鹏蛟,等.砂土地区深基坑稳定性评价及力学效应分析[J].东北大学学报(自然科学版),2018,39(9):1353-1357.
[13]廖庄. 粉、砂土地层地铁车站支护结构力学与变形特性研究[D].杭州:浙江工业大学,2014.
[14]杨瑞意. 灰色GM-BP神经网络预测超期服役深基坑变形应用研究[D].广州:华南理工大学,2018.
[15]高洲.考虑淤泥蠕变效应的深基坑开挖变形特性分析[D].扬州:扬州大学,2021.
[16]刘燕,刘国彬,孙晓玲,等.考虑时空效应的软土地区深基坑变形分析[J].岩土工程学报, 2006(S1):1433-1436.
[17]HARAHAP Syiril,OU changyu. Finite element analysis of time-dependent behavior in deep excavations[J]. Computers and Geotechnics,2020,119: 103300.
[19]孙钧.岩土材料流变及其工程应用[M].北京:中国建筑工业出版社,1999.
[20]高昳菲. 淤泥质土的流变特性及其工程应用研究[D]. 南京:南京航空航天大学,2018.
[21]范厚彬.基于层叠模型的盾构隧道施工对周围环境的影响[J].岩石力学与工程学报,2005(6):1092.

pdf格式下载

+分享

期刊信息

西安建筑科技大学学报(自然科学版)
（1957年创刊双月刊）

主管单位：陕西省教育厅

主办单位：西安建筑科技大学

主　　编：刘加平（院士）

副主编：史庆轩（常务）张引科张小龙

国内刊号：CN61-1295/TU

I S S N：1006-7930

地　　址：西安市雁塔路中段13号

国内发行：西安建筑科技大学学报编辑部

国外发行：中国出版对外贸易总公司

编辑出版：西安建筑科技大学学报编辑部

备注

引言

1 问题的提出

2 粉细砂土耦合蠕变模型

3 有限元模型建立

4 计算结果分析

5 实测数据与计算结果对比

6 结论

期刊信息