本文選題：隧道　切入點：空間約束效應　出處：《重慶大學》2014年碩士論文　論文類型：學位論文

【摘要】：隧道是賦存于巖土體中的地下結構物,它和地上結構物的不同之處在于隧道周圍的巖土體是它的主要研究對象，巖土體的穩(wěn)定性和變形規(guī)律是隧道工程人員非常關心的一個問題。由于受到賦存環(huán)境的強烈影響，所以巖土體的物理、力學、構造和時間性質(zhì)都非常復雜，因此科學的認識它的各種性質(zhì)以及隧道開挖后它和支護結構之間的相互作用是一個比較困難的問題，但是國內(nèi)外的科研工作者和隧道工程設計人員通過大量的理論分析和工程實踐，已經(jīng)取得了重大的成果，建立了比較完善的隧道工程設計理論。 隧道開挖面的存在對附近的圍巖產(chǎn)生了一個徑向約束的作用，相當于施加了一個虛擬支護力，圍巖的位移和應力會隨著開挖面的推進而發(fā)生變化,我們稱之為開挖面的空間效應。本文將在隧道空間效應理論已取得的研究成果的基礎上，對以下幾個問題進一步研究,論文的主要工作如下: ①對空間效應的產(chǎn)生機理、反映空間效應約束損失的約束損失因子進行分析；并且在考慮了空間效應的基礎上分析圍巖的位移釋放，建立了位移釋放系數(shù)和約束損失因子之間的關系；最后對考慮空間效應的圍巖-支護作用機制進行分析。 ②采用有限元分析軟件對淺埋直墻拱形隧道的循環(huán)開挖進行數(shù)值模擬,得出圍巖的縱斷面變形曲線和位移釋放系數(shù)曲線,分析隧道的空間效應。由于在開挖面空間效應的影響范圍內(nèi),圍巖主要產(chǎn)生彈塑性變形，因此本文還將基于摩爾-庫倫強度理論，采用數(shù)值模擬的方法分析巖體的物理力學參數(shù)以及隧道的埋深比（H/R）對圍巖位移釋放系數(shù)的影響。 ③在②中研究成果基礎上，確定圍巖位移釋放系數(shù)的影響參數(shù)，以IV級圍巖為例，采用有限元數(shù)值模擬的方法建立樣本集。以影響參數(shù)的取值作為輸入量，，位移釋放系數(shù)的取值作為輸出量，訓練BP人工神經(jīng)網(wǎng)絡；并且對其進行驗證，確保網(wǎng)絡訓練的精度。 ④以重慶兩江橋渝中連接隧道某一區(qū)段為例,采用③中得到的神經(jīng)網(wǎng)絡預測出圍巖的位移釋放系數(shù)曲線,并且就位移釋放系數(shù)在選擇支護時機時的應用進行分析。 在實際工程中，合理的預估圍巖的位移釋放系數(shù)對于指導隧道安全合理的施工具有重要的意義。傳統(tǒng)的方法主要通過理論計算或數(shù)值模擬來確定圍巖的位移釋放系數(shù)，而這些方法往往比較復雜而且需要耗費較多的時間。本文提出采用人工神經(jīng)網(wǎng)絡方法實現(xiàn)圍巖位移釋放系數(shù)的預測；與傳統(tǒng)方法相比，其簡單有效并且具有較高的精度，從而具有極高的工程應用價值和實際意義。
[Abstract]:Tunnel is an underground structure existing in rock and soil. The difference between tunnel and above ground structure is that the rock and soil around the tunnel is its main research object. The stability and deformation of rock and soil are a problem of great concern to tunnel engineers. Due to the strong influence of the environment, the physical, mechanical, structural and temporal properties of rock and soil are very complicated. Therefore, it is a difficult problem to understand scientifically its various properties and the interaction between it and the supporting structure after the excavation of the tunnel. However, through a large number of theoretical analysis and engineering practice, researchers and tunnel designers at home and abroad have made great achievements and established a relatively perfect theory of tunnel engineering design. The existence of tunnel excavation surface has a radial constraint effect on the surrounding rock nearby, which is equivalent to applying a virtual support force, and the displacement and stress of surrounding rock will change with the advance of excavating surface. We call it the spatial effect of excavated surface. Based on the research results of tunnel spatial effect theory, the following problems are further studied in this paper. The main work of this paper is as follows:. The main contents are as follows: (1) the mechanism of spatial effect is analyzed, and the constraint loss factor reflecting the constraint loss of spatial effect is analyzed, and the displacement release of surrounding rock is analyzed based on the consideration of spatial effect. The relationship between displacement release coefficient and constraint loss factor is established. Finally, the mechanism of surrounding rock support with space effect is analyzed. (2) numerical simulation of circular excavation of shallow buried vertical wall arch tunnel is carried out by using finite element analysis software, and the deformation curve and displacement release coefficient curve of surrounding rock are obtained. The spatial effect of tunnel is analyzed. Because the surrounding rock mainly produces elastoplastic deformation in the range of spatial effect of excavating surface, this paper will also base on the Moorl-Coulomb strength theory. The influence of the physical and mechanical parameters of rock mass and the ratio of buried depth of tunnel to the displacement release coefficient of surrounding rock is analyzed by numerical simulation. 3 on the basis of 2 research results, the influence parameters of displacement release coefficient of surrounding rock are determined. Taking class IV surrounding rock as an example, the sample set is established by means of finite element numerical simulation, and the value of influence parameter is taken as the input quantity. The displacement release coefficient is used as the output value to train BP artificial neural network and verify it to ensure the accuracy of network training. 4 taking a section of Yuzhong tunnel connecting Liangjiang Bridge in Chongqing as an example, the displacement release coefficient curve of surrounding rock is predicted by using the neural network obtained in 3, and the application of displacement release coefficient in selecting supporting time is analyzed. In the actual engineering, it is important to estimate the displacement release coefficient of surrounding rock reasonably for guiding the safe and reasonable construction of tunnel. The traditional method mainly determines the displacement release coefficient of surrounding rock by theoretical calculation or numerical simulation. However, these methods are often more complicated and need more time. In this paper, artificial neural network method is proposed to predict the displacement release coefficient of surrounding rock. Compared with the traditional method, the method is simple, effective and has higher accuracy. Therefore, it has high engineering application value and practical significance.
【學位授予單位】：重慶大學
【學位級別】：碩士
【學位授予年份】：2014
【分類號】：U451.2

【參考文獻】

相關期刊論文 前10條

1 張衛(wèi)國,姜椺,張偉;地下工程結構計算方法概述[J];地下空間;2002年03期

2 閆春嶺;丁德馨;崔振東;畢忠偉;;FLAC在鐵山坪隧道圍巖穩(wěn)定性分析中的應用[J];地下空間與工程學報;2006年03期

3 田坤;黃炳仁;王瑞;;考慮滲流效應下的常吉高速公路隧道數(shù)值模擬[J];水利與建筑工程學報;2007年04期

4 李俊鵬;段小強;閆小虎;;開挖過程中隧洞圍巖應力釋放規(guī)律的數(shù)值研究[J];水利與建筑工程學報;2007年04期

5 孫元春;尚彥軍;;巖石隧道圍巖變形時空效應分析[J];工程地質(zhì)學報;2008年02期

6 張俊艷;馮守中;劉東海;;基于RBF神經(jīng)網(wǎng)絡的隧洞圍巖變形預測方法[J];中國工程科學;2005年10期

7 汪成兵;劉豐軍;王士民;;基于三維有限元分析的隧道開挖效應研究[J];公路;2007年02期

8 馬萬權,王新平,程崇國;神經(jīng)網(wǎng)絡技術在陽宗隧道圍巖變形預測中的應用[J];公路交通技術;2003年02期

9 龍浩;高睿;孔德新;劉鵬;;基于BP神經(jīng)網(wǎng)絡-馬爾科夫鏈模型的隧道圍巖位移預測[J];長江科學院院報;2013年03期

10 黃志波;林從謀;黃金山;孟凡兵;付旭;;BP小波神經(jīng)網(wǎng)絡在大斷面隧道變形預測中的應用[J];華僑大學學報(自然科學版);2011年06期

相關博士學位論文 前1條

1 張莉;幾類神經(jīng)網(wǎng)絡的分析與優(yōu)化及其應用研究[D];西安電子科技大學;2012年

本文編號：1569708