本文關(guān)鍵詞：北京地鐵大紅門車站基坑變形特征研究　出處：《中國地質(zhì)大學(xué)(北京)》2017年碩士論文　論文類型：學(xué)位論文

  更多相關(guān)文章： 地鐵基坑 基坑變形 基坑監(jiān)測(cè) FLAC3D 數(shù)值模擬

【摘要】：隨著我國1978年改革開放以來,經(jīng)濟(jì)的飛速增長,城市化進(jìn)程帶來的交通擁堵問題愈加突出,地鐵建設(shè)是解決此問題行之有效的方法之一。但是,地鐵建設(shè)會(huì)對(duì)周圍環(huán)境產(chǎn)生很大的負(fù)面效應(yīng),最近幾年地鐵車站基坑施工引發(fā)的工程事故時(shí)有發(fā)生,這也警示我們對(duì)基坑變形的研究時(shí)時(shí)不能松懈。因此,基坑穩(wěn)定性研究成為許多學(xué)者研究的一個(gè)熱點(diǎn)課題。本文主要介紹了基坑工程目前的研究發(fā)展?fàn)顩r,該工程的工程概況、工程地質(zhì)條件、開挖支護(hù)方案以及監(jiān)測(cè)方案,然后對(duì)所得到的監(jiān)測(cè)數(shù)據(jù)進(jìn)行分析歸納,得出基坑的周圍地表沉降、圍護(hù)結(jié)構(gòu)的變形以及內(nèi)支撐軸力在時(shí)間上、空間上變化規(guī)律。最后簡(jiǎn)單介紹了數(shù)值模擬軟件FLAC3D原理,詳細(xì)介紹了基坑數(shù)值模擬模型的建立:包括計(jì)算范圍、本構(gòu)模型、結(jié)構(gòu)單元、計(jì)算參數(shù)、邊界條件以及施工開挖步驟,采用FLAC3D有限差分程序?qū)Υ蠹t門地鐵車站基坑在開挖深度2.3m,10.3m,16.8m,20.1m,24.3m,27.0m處周圍地表沉降,基坑支護(hù)結(jié)構(gòu)水平方向上的位移和鋼支撐軸力變化規(guī)律進(jìn)行了模擬,最后與實(shí)際監(jiān)測(cè)結(jié)果相比較,驗(yàn)證基坑變形普遍規(guī)律。本文的主要研究結(jié)果如下:空間上沉降曲線呈“煙斗狀”;在距離基坑邊緣相同距離情況下,基坑長邊附近地面沉降值普遍大于短邊附近地面沉降值;根據(jù)一級(jí)基坑變形控制標(biāo)準(zhǔn)地表沉降控制值應(yīng)為30mm,本次監(jiān)測(cè)結(jié)果顯示地表沉降最大變形值為11.90mm,遠(yuǎn)低于控制值,基坑安全性較好。圍護(hù)結(jié)構(gòu)變形曲線整體上由“前傾型”逐漸向“弓形”發(fā)展,最后變化趨于穩(wěn)定;基坑連續(xù)墻最大水平位移為13.52mm,發(fā)生在深度18m左右的位置,明顯小于地連墻墻體水平位移累計(jì)變化控制值20mm,說明基坑明挖法開挖以及地連墻+內(nèi)支撐支護(hù)體系能夠較好地控制基坑的側(cè)向變形,保證基坑工程的安全�？傮w上鋼支撐的軸力會(huì)不斷增大,并且第三道鋼支撐的變化幅度最大。數(shù)值模擬計(jì)算結(jié)果同現(xiàn)場(chǎng)實(shí)際監(jiān)測(cè)數(shù)據(jù)做對(duì)比總體上相對(duì)于實(shí)際值偏小,但是數(shù)值模擬計(jì)算得到的變形規(guī)律與實(shí)際監(jiān)測(cè)得到的基坑變形規(guī)律基本一致,本文的模擬結(jié)果可為日后該地區(qū)其他工程設(shè)計(jì)和施工提供指導(dǎo)和參考。
[Abstract]:With the rapid growth of economy since the reform and opening up in 1978, the problem of traffic congestion brought by the process of urbanization has become more and more prominent. Subway construction is one of the effective methods to solve this problem. Subway construction will have a great negative effect on the surrounding environment. In recent years, engineering accidents caused by subway station foundation pit construction have occurred from time to time, which also warns us that the study of foundation pit deformation can not be relaxed. The research of foundation pit stability has become a hot topic for many scholars. This paper mainly introduces the current research and development of foundation pit engineering, the general situation of the project and the engineering geological conditions. Excavation support scheme and monitoring scheme, and then analysis and induction of the monitoring data, the ground subsidence around the foundation pit, the deformation of the retaining structure and the internal support axial force in time. Finally, the principle of numerical simulation software FLAC3D is briefly introduced, and the establishment of numerical simulation model of foundation pit is introduced in detail, including calculation range, constitutive model, structure element and calculation parameters. The boundary condition and the construction excavation procedure are used to excavate the excavation depth of the excavation depth of the excavation depth of 2.3m10. 3mand 16.8mb / m by using the FLAC3D finite difference program for the foundation pit of the Dahongmen subway station. The surface settlement around 24.3mm or 27.0m, the horizontal displacement of foundation pit support structure and the variation law of steel support axial force are simulated. Finally, the results are compared with the actual monitoring results. The main results of this paper are as follows: the settlement curve in space is "pipe shape"; In the case of the same distance from the edge of the foundation pit, the value of the ground settlement near the long edge of the foundation pit is generally larger than that near the short side. According to the first class foundation pit deformation control standard surface settlement control value should be 30 mm, this monitoring result shows the surface settlement maximum deformation value is 11.90 mm, is far lower than the control value. On the whole, the deformation curve of the retaining structure develops from "forward tilting" to "bow", and the change tends to be stable at last. The maximum horizontal displacement of the continuous wall of foundation pit is 13.52 mm, which occurs at a depth of about 18 m, which is obviously smaller than the cumulative control value of 20 mm in the horizontal displacement of the wall connected to the ground. The results show that excavation of foundation pit and bracing system can control the lateral deformation of foundation pit and ensure the safety of foundation pit engineering. In general, the axial force of steel braces will increase continuously. And the change of the third steel bracing is the biggest. Compared with the actual monitoring data, the numerical simulation results are smaller than the actual values. But the deformation law obtained by numerical simulation is basically consistent with the deformation law of foundation pit obtained by actual monitoring. The simulation results in this paper can provide guidance and reference for the design and construction of other projects in this area in the future.
【學(xué)位授予單位】：中國地質(zhì)大學(xué)(北京)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2017
【分類號(hào)】：U231.3;TU433
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本文編號(hào)：1441097