地鐵車站狹長(zhǎng)基坑支撐異常軸力分析

劉利國(guó) 羅家文 朱碧堂

收稿日期：2023-12-15

基金項(xiàng)目：國(guó)家自然科學(xué)基金項(xiàng)目（52208343，52020105003）

文章編號(hào)：1005-0523（2024）03-0020-09

摘要：【目的】研究地鐵車站狹長(zhǎng)型基坑施工過(guò)程中第一道支撐軸力過(guò)大的問(wèn)題。【方法】通過(guò)土體小應(yīng)變剛度硬化模型（HSS）有限元分析，對(duì)車站基坑土方的開挖方式、鋼支撐安裝質(zhì)量差、鋼支撐未及時(shí)受力等情況進(jìn)行精細(xì)化模擬，分析其對(duì)第一道支撐軸力的影響。【結(jié)果】結(jié)果表明：采用盆式開挖對(duì)第一道支撐的軸力影響顯著，相較分層開挖的情況增大45%，應(yīng)及時(shí)安裝對(duì)應(yīng)位置的鋼支撐；安裝鋼支撐的預(yù)應(yīng)力未達(dá)到設(shè)計(jì)值時(shí)，會(huì)導(dǎo)致開挖到底時(shí)的頂層支撐軸力增大，增大幅度在10%以內(nèi)，底層支撐軸力減小。【結(jié)論】在地鐵車站狹長(zhǎng)基坑開挖過(guò)程中應(yīng)限制盆式超挖；溫度變化對(duì)支撐軸力的影響不能忽視；安裝下層鋼支撐預(yù)應(yīng)力達(dá)不到設(shè)計(jì)值時(shí)，會(huì)導(dǎo)致開挖到底時(shí)的頂部支撐軸力偏大。

關(guān)鍵詞：狹長(zhǎng)型基坑；支撐軸力；土體小應(yīng)變硬化模型；盆式開挖

中圖分類號(hào)：U231.4；TU52 文獻(xiàn)標(biāo)志碼：A

本文引用格式：劉利國(guó)，羅家文，朱碧堂.地鐵車站狹長(zhǎng)基坑支撐異常軸力分析[J]. 華東交通大學(xué)學(xué)報(bào)，2024，41（3）：20-28.

Analysis of Abnormal Strut Axial Forces for Narrow and

Long Deep Excavation of Metro Stations

Liu Liguo1，Luo Jiawen2，3，Zhu Bitang2，3

（1. China Railway No.4 Group Co.， Ltd.， Hefei 230023， China; 2. School of Civil Engineering and Architecture， East China Jiaotong University， Nanchang 330013， China; 3. Engineering R&D Centre for Underground Technology of

Jiangxi Province， Nanchang 330013， China）

Abstract： 【Objective】The purpose of this paper is to address the issue of excessive axial force in the first support of a narrow and long deep excavation of metro stations during construction.【Method】Through the method of finite element analysis using the hardening soil model with small strain stiffness （HSS）， the excavation method of the station pit ， poor quality of steel support installation， and the untimely stressing of the steel support are simulated in a refined way to analyze the influence on the axial force of the first support. 【Result】The results show that the use of basin excavation has a significant effect on the axial force of the first support， which increases by 45% compared with the case of layered excavation， and the corresponding position of the steel support should be installed in time; when the prestress of the installed steel support does not reach the design value， it will lead to an increase in the axial force of the top support at the end of the excavation， with an increase of 10% or less， and a decrease in the axial force of the bottom support.【Conclusion】Basin over-excavation should be strictly limited during excavation of narrow and long deep excavation of metro stations; The effect of temperature changes on support axial forces cannot be ignored; when the prestressing force of the installed lower steel support fails to reach the design value， it will lead to a large axial force of the top support at the bottom of excavation.

Key words： narrow and long deep excavation; strut axial force; hardening soil model with small strain stiffness; basin excavation method

Citation format： LIU L G， LUO J W， ZHU B T. Analysis of abnormal strut axial forces for narrow and long deep excavations of metro stations[J]. Journal of East China Jiaotong University， 2024， 41（3）： 20-28.

【研究意義】近年來(lái)為了滿足工程需要，地鐵車站基坑工程的規(guī)模呈現(xiàn)向“深、大、長(zhǎng)”發(fā)展的態(tài)勢(shì)[1-2]。地鐵基坑為滿足地鐵車輛編組的停靠和乘客上下?lián)Q乘效率的要求，一般長(zhǎng)度大于200 m、寬約20 m，開挖深度17～26 m，屬于狹長(zhǎng)型基坑，長(zhǎng)邊效應(yīng)和坑角效應(yīng)明顯[3]，周圍環(huán)境復(fù)雜，既有建筑構(gòu)筑物易受到基坑開挖引起的土體應(yīng)力釋放影響，已成為目前地鐵施工的突出問(wèn)題[4]。……