本文選題：隧道　切入點(diǎn)：空間約束效應(yīng)　出處：《重慶大學(xué)》2014年碩士論文　論文類型：學(xué)位論文

【摘要】：隧道是賦存于巖土體中的地下結(jié)構(gòu)物,它和地上結(jié)構(gòu)物的不同之處在于隧道周圍的巖土體是它的主要研究對(duì)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(guān)心的一個(gè)問(wèn)題。由于受到賦存環(huán)境的強(qiáng)烈影響，所以巖土體的物理、力學(xué)、構(gòu)造和時(shí)間性質(zhì)都非常復(fù)雜，因此科學(xué)的認(rèn)識(shí)它的各種性質(zhì)以及隧道開(kāi)挖后它和支護(hù)結(jié)構(gòu)之間的相互作用是一個(gè)比較困難的問(wèn)題，但是國(guó)內(nèi)外的科研工作者和隧道工程設(shè)計(jì)人員通過(guò)大量的理論分析和工程實(shí)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(shè)計(jì)理論。 隧道開(kāi)挖面的存在對(duì)附近的圍巖產(chǎn)生了一個(gè)徑向約束的作用，相當(dāng)于施加了一個(gè)虛擬支護(hù)力，圍巖的位移和應(yīng)力會(huì)隨著開(kāi)挖面的推進(jìn)而發(fā)生變化,我們稱之為開(kāi)挖面的空間效應(yīng)。本文將在隧道空間效應(yīng)理論已取得的研究成果的基礎(chǔ)上，對(duì)以下幾個(gè)問(wèn)題進(jìn)一步研究,論文的主要工作如下: ①對(duì)空間效應(yīng)的產(chǎn)生機(jī)理、反映空間效應(yīng)約束損失的約束損失因子進(jìn)行分析；并且在考慮了空間效應(yīng)的基礎(chǔ)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(guān)系；最后對(duì)考慮空間效應(yīng)的圍巖-支護(hù)作用機(jī)制進(jìn)行分析。 ②采用有限元分析軟件對(duì)淺埋直墻拱形隧道的循環(huán)開(kāi)挖進(jìn)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(yīng)。由于在開(kāi)挖面空間效應(yīng)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(kù)倫強(qiáng)度理論，采用數(shù)值模擬的方法分析巖體的物理力學(xué)參數(shù)以及隧道的埋深比（H/R）對(duì)圍巖位移釋放系數(shù)的影響。 ③在②中研究成果基礎(chǔ)上，確定圍巖位移釋放系數(shù)的影響參數(shù)，以IV級(jí)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(xùn)練BP人工神經(jīng)網(wǎng)絡(luò)；并且對(duì)其進(jìn)行驗(yàn)證，確保網(wǎng)絡(luò)訓(xùn)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(luò)預(yù)測(cè)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(hù)時(shí)機(jī)時(shí)的應(yīng)用進(jìn)行分析。 在實(shí)際工程中，合理的預(yù)估圍巖的位移釋放系數(shù)對(duì)于指導(dǎo)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(guò)理論計(jì)算或數(shù)值模擬來(lái)確定圍巖的位移釋放系數(shù)，而這些方法往往比較復(fù)雜而且需要耗費(fèi)較多的時(shí)間。本文提出采用人工神經(jīng)網(wǎng)絡(luò)方法實(shí)現(xiàn)圍巖位移釋放系數(shù)的預(yù)測(cè)；與傳統(tǒng)方法相比，其簡(jiǎn)單有效并且具有較高的精度，從而具有極高的工程應(yīng)用價(jià)值和實(shí)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(xué)位授予單位】：重慶大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2014
【分類號(hào)】：U451.2

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