|Table of Contents|

Influence laws of excavation sequence and early stiffness of inner support on stability of foundation pit in soft soil(PDF)

《建筑科学与工程学报》[ISSN:1673-2049/CN:61-1442/TU]

Issue:
2024年02期
Page:
181-190
Research Field:
岩土工程
Publishing date:

Info

Title:
Influence laws of excavation sequence and early stiffness of inner support on stability of foundation pit in soft soil
Author(s):
GUAN Dagang1; 2;  HU Zhiming1;  ZHENG Pengpeng1;  YUAN Shan2;  CHEN Baoguo2;  ZHANG Yanlin1
(1. Sinohydro Bureau 7 Co., Ltd, Chengdu 610081, Sichuan, China; 2. Faculty of Engineering, China University of Geosciences, Wuhan 430074, Hubei, China)
Keywords:
deep foundation pit;  soft soil;  excavation sequence;  concrete inner support;  early stiffness;  deformation characteristic
PACS:
TU94
DOI:
10.19815/j.jace.2022.03084
Abstract:
Deformation control of deep excavation is a difficult problem for deep foundation pit engineering in soft soil, and dense concrete inner supports are often used in engineering to improve support stiffness. However, the excavation sequence of deep foundation pit in soft soil and the early stiffness of concrete inner support are not reasonably considered in practice, which often cause the actual deformation of the foundation pit greater than the design value. According to the deep foundation pit in the Pearl River delta water resources allocation project, the verified numerical simulation method was used to study the influence laws of different excavation sequences and the early stiffness of concrete inner supports on the stress and deformation characteristics of soft soil foundation pit. The influence laws of asymmetric and/or symmetrical excavation on the diaphragm wall horizontal displacement and ground surface settlement were obtained. The results show that although asymmetric excavation will cause the displacement of diaphragm wall and surface settlement difference on both sides of foundation pit, asymmetric excavation can reduce time significantly compared with symmetrical excavation in the case of dense inner support. Moreover, due to the early stiffness of the concrete inner support, the earlier the next excavation is carried out after the applying inner support, the greater the diaphragm wall horizontal displacement and ground surface settlement will be. Considering the influence of the early stiffness of the inner support, the axial force of the inner support in the upper part of the foundation pit will increase, while the axial force of the inner support in the lower part will decrease, this trend will be more obvious at a lower early stiffness. Meanwhile, it is difficult to dynamically monitor the elastic modulus of concrete in real time during on-site construction, which is easy to cause the distortion of early monitoring data of inner support axial force, and even bring wrong decision-making to the project.

References:

[1] 曹文昭,杨志银,蔡巧灵,等.软土地基超长桩静载试验中桩侧堆载影响分析[J].建筑科学与工程学报,2021,38(6):1-10.
CAO Wenzhao,YANG Zhiyin,CAI Qiaoling,et al.Effect of surrounding load on static load test of super-long pile in soft soil foundation[J].Journal of Architecture and Civil Engineering,2021,38(6):1-10.
[2]王卫东,胡 耘,沈 健,等.软土地基历史建筑地下空间开发的设计与实践[J].岩土工程学报,2023,45(12):2445-2453.
WANG Weidong,HU Yun,SHEN Jian,et al.Design and practice of underground space development of existing historical buildings in soft soils[J].Chinese Journal of Geotechnical Engineering,2023,45(12):2445-2453.
[3]于至海,吴旭君,曹文昭.软土深基坑被动区超前加固变形控制效果研究[J].建筑科学与工程学报,2021,38(6):71-79.
YU Zhihai,WU Xujun,CAO Wenzhao.Research on deformation control effect of passive zone reinforcement before excavation of deep foundation pit in soft soil[J].Journal of Architecture and Civil Engineering,2021,38(6):71-79.
[4]张 楠,李 波,王天成,等.软土地基堤防稳定性离心模型试验研究[J].岩土工程学报,2023,45(增1):222-225.
ZHANG Nan,LI Bo,WANG Tiancheng,et al.Centrifugal model test of embankment stability on soft soil foundation[J].Chinese Journal of Geotechnical Engineering,2023,45(S1):222-225.
[5]李煜峰,傅 怡,徐中华.软土地区紧邻地铁隧道深基坑支护设计与实践[J].建筑科学与工程学报,2021,38(6):128-137.
LI Yufeng,FU Yi,XU Zhonghua.Supporting design and application of deep excavation adjacent to metro tunnels in soft soil area[J].Journal of Architecture and Civil Engineering,2021,38(6):128-137.
[6]陆金钰,舒海港,姜昊瑞.地下结构-软土地基-钢框架结构相互作用体系地震响应数值模拟研究[J].建筑结构学报,2023,44(增2):375-384.
LU Jinyu,SHU Haigang,JIANG Haorui.Numerical simulation study on seismic response of underground structure-soft soil foundation-steel frame structure interaction system[J].Journal of Building Structures,2023,44(S2):375-384.
[7]TERZAGHI K,PECK R B.Soil mechanics in engineering practice[M].2nd ed.New York:Wiley,1967.
[8]TERZAGHI K.General wedge theory of earth pressure[J].Transactions of the American Society of Civil Engineers,1941,106(1):68-80.
[9]程 康,徐日庆,应宏伟,等.杭州软黏土地区某30.2 m深大基坑开挖性状实测分析[J].岩石力学与工程学报,2021,40(4):851-863.
CHENG Kang,XU Riqing,YING Hongwei,et al.Performance analysis of a 30.2 m deep-large excavation in Hangzhou soft clay[J].Chinese Journal of Rock Mechanics and Engineering,2021,40(4):851-863.
[10]李福林.软土地区狭长型深基坑开挖引起深层土体变形分析[J].现代隧道技术,2019,56(6):121-127.
LI Fulin.Analysis on the deep soil deformation induced by construction of narrow long excavation pit in soft ground area[J].Modern Tunnelling Technology,2019,56(6):121-127.
[11]鲁泰山,刘松玉,蔡国军,等.软土地层基坑开挖扰动及土体再压缩变形研究[J].岩土力学,2021,42(2):565-573,580.
LU Taishan,LIU Songyu,CAI Guojun,et al.Study on the disturbance and recompression settlement of soft soil induced by foundation excavation[J].Rock and Soil Mechanics,2021,42(2):565-573,580.
[12]徐 江,龚维明,穆保岗,等.软土区某地铁深基坑施工过程数值模拟及现场监测[J].东南大学学报(自然科学版),2017,47(3):590-598.
XU Jiang,GONG Weiming,MU Baogang,et al.Numerical simulation and monitoring on construction process of deep pit of subway station in soft clay[J].Journal of Southeast University(Natural Science Edition),2017,47(3):590-598.
[13]孙九春,白廷辉.软土地铁深基坑小尺度盆式挖土法研究与应用[J].地下空间与工程学报,2021,17(4):1244-1252.
SUN Jiuchun,BAI Tinghui.Study and application of small scale basin method for deep foundation pit of metro in soft soil[J].Chinese Journal of Underground Space and Engineering,2021,17(4):1244-1252.
[14]CHEN J J,WANG J H,XIANG G W,et al.Numerical study on the movement of existing tunnel due to deep excavation in Shanghai[J].Geotechnical Engineering Journal of the SEAGS&AGSSEA,2011,42(3):30-40.
[15]LONG M.Database for retaining wall and ground movements due to deep excavations[J].Journal of Geotechnical and Geoenvironmental Engineering,2001,127(3):203-224.
[16]FINNO R J,BLACKBURN J T,ROBOSKI J F.Three-dimensional effects for supported excavations in clay[J].Journal of Geotechnical and Geoenvironmental Engineering,2007,133(1):30-36.
[17]刘美麟,房 倩,张顶立,等.深基坑内撑式支护结构综合刚度研究[J].岩土力学,2017,38(7):2059-2064.
LIU Meilin,FANG Qian,ZHANG Dingli,et al.Research on synthetic system stiffness of strutted retaining structure for deep excavation[J].Rock and Soil Mechanics,2017,38(7):2059-2064.
[18]金亚兵,沈 翔,劳丽燕.温度变化对深基坑内支撑轴力和变形的影响研究[J].岩土工程学报,2021,43(8):1417-1425.
JIN Yabing,SHEN Xiang,LAO Liyan.Influences of temperature change on axial force and deformation of inner support in deep foundation pits[J].Chinese Journal of Geotechnical Engineering,2021,43(8):1417-1425.
[19]张 戈,毛海和.软土地区深基坑围护结构综合刚度研究[J].岩土力学,2016,37(5):1467-1474.
ZHANG Ge,MAO Haihe.A new system stiffness of retaining structure of deep foundation pit in soft soil area[J].Rock and Soil Mechanics,2016,37(5):1467-1474.
[20]贺振昭,杨 新,叶 超,等.地铁深基坑内支撑结构优化分析[J].安全与环境工程,2021,28(1):68-78.
HE Zhenzhao,YANG Xin,YE Chao,et al.Optimization analysis of supporting structure in deep excavation of metro[J].Safety and Environmental Engineering,2021,28(1):68-78.
[21]徐昭辰,王 强,章定文,等.基坑混凝土支撑轴力监测值修正方法[J].建筑科学与工程学报,2021,38(6):48-54.
XU Zhaochen,WANG Qiang,ZHANG Dingwen,et al.Correction method of axial force monitoring value of concrete strut in excavation[J].Journal of Architecture and Civil Engineering,2021,38(6):48-54.
[22]肖振烨,李素贞,崔晓强.基于应变监测的基坑钢筋混凝土支撑轴力修正方法[J].重庆大学学报,2018,41(11):8-18.
XIAO Zhenye,LI Suzhen,CUI Xiaoqiang.Study on force correction method of reinforced concrete brace shaft in foundation ditch based on strain monitoring[J].Journal of Chongqing University,2018,41(11):8-18.
[23]张 浩,吴志鸿,张 峰,等.深基坑混凝土支撑轴力精确性分析[J].地下空间与工程学报,2018,14(增1):342-348.
ZHANG Hao,WU Zhihong,ZHANG Feng,et al.Accuracy analysis on axial force of concrete support in deep foundation pit[J].Chinese Journal of Underground Space and Engineering,2018,14(S1):342-348.
[24]张 哲.基坑混凝土支撑轴力监测数据异常情况分析与探讨[J].隧道建设,2016,36(8):976-981.
ZHANG Zhe.Analysis and discussion of monitoring data anomaly of axial force for concrete support of foundation pit[J].Tunnel Construction,2016,36(8):976-981.
[25]建筑基坑支护技术规程:JGJ 120—2012[S].北京:中国建筑工业出版社,2012.
Technical specification for retaining and protection of building foundation excavations:JGJ 120—2012[S].Beijing:China Architecture & Building Press,2012.
[26]朱伯芳.混凝土的弹性模量、徐变度与应力松弛系数[J].水利学报,1985,16(9):54-61.
ZHU Bofang.Elastic modulus,creep and stress relaxation coefficient of concrete[J].Journal of Hydraulic Engineering,1985,16(9):54-61.
[27]朱伯芳.再论混凝土弹性模量的表达式[J].水利学报,1996,27(3):89-91,88.
ZHU Bofang.On the formula for modulus of elasticity of concrete[J].Journal of Hydraulic Engineering,1996,27(3):89-91,88.

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Last Update: 2024-03-25