發(fā)布時(shí)間：2018-03-04 02:02

  本文選題：導(dǎo)流隧洞　切入點(diǎn)：不良地質(zhì)　出處：《天津大學(xué)》2015年博士論文　論文類型：學(xué)位論文

【摘要】：大型水電工程的導(dǎo)流隧洞大多為淺埋、大斷面洞室,在施工過程中,隧洞與進(jìn)口邊坡的施工及安全性相互影響、相互制約,一旦工程發(fā)生圍巖穩(wěn)定事故,不僅造成施工人員生命財(cái)產(chǎn)的損失,而且嚴(yán)重影響施工進(jìn)度,因此大型水電站導(dǎo)流隧洞施工期的隧洞圍巖及洞口邊坡的穩(wěn)定性一直是巖土工程界關(guān)注的重點(diǎn)問題。對(duì)于大型水電站導(dǎo)流隧洞,考慮進(jìn)口洞段邊坡與隧洞相互影響的結(jié)構(gòu)設(shè)計(jì)與施工是一個(gè)受眾多因素影響的復(fù)雜過程,無規(guī)范可循,工程類比少,且不良地質(zhì)洞段的施工技術(shù)及其安全性在隧洞施工過程中直接影響工程的整體進(jìn)度,因此有必要針對(duì)不良地質(zhì)大斷面隧洞的施工技術(shù)及圍巖力學(xué)行為特征進(jìn)行深入研究,以指導(dǎo)工程實(shí)際施工。本文結(jié)合我國西南某大型水電站為工程實(shí)例,采用巖石力學(xué)和數(shù)值分析方法等技術(shù)手段,通過分析不良地質(zhì)大斷面隧洞圍巖及邊坡的力學(xué)行為特征,研究隧洞圍巖與邊坡作用機(jī)制及隧洞施工技術(shù),探討安全、合理的施工方法。具體研究內(nèi)容和成果如下:(1)在依托工程地質(zhì)條件和背景下,分析了大斷面地下洞室中的超前支護(hù)措施、噴錨支護(hù)機(jī)理與效果、拱架及鋼筋網(wǎng)支護(hù)機(jī)理。超前支護(hù)主要改良地層特性和預(yù)支護(hù)作用。噴混對(duì)隧洞圍巖進(jìn)行加固主要有支承圍巖、卸載作用、填平補(bǔ)強(qiáng)圍巖、覆蓋圍巖表面、防止松動(dòng)和分配外力等作用,采用混凝土噴層加固隧洞可有效地控制圍巖變形,能有效遏制巖體塑性區(qū)的發(fā)展,防止圍巖松動(dòng)失穩(wěn)。提高噴層厚度可有效減小隧洞頂拱塑性區(qū)范圍,但厚度過大有可能造成拱腳處塑性區(qū)范圍因應(yīng)力集中而增大,采用標(biāo)號(hào)較高的混凝土作為噴層材料對(duì)于限制圍巖頂拱變形具有一定的作用,但效果不明顯。(2)總結(jié)了隧洞進(jìn)口圍巖—邊坡作用體系類型與力學(xué)模型,考慮隧洞—邊坡的耦聯(lián)作用機(jī)制,深入研究了隧洞施工對(duì)邊坡的影響及邊坡施工對(duì)隧洞圍巖穩(wěn)定性的影響,探討了隧洞圍巖與邊坡體系穩(wěn)定性演化特征,并提出了合理的進(jìn)洞順序。具體內(nèi)容涉及四方面:(1)探討了隧洞進(jìn)口圍巖與邊坡相互作用的平行、正交和斜交三種體系類型,建立了相應(yīng)的地質(zhì)力學(xué)模型,并討論了邊坡與隧洞變形相互作用的順滑型、剪切型、擾動(dòng)型和順滑剪切復(fù)合型等幾種力學(xué)模型;(2)考慮隧洞進(jìn)口圍巖—邊坡正交作用體系,深入研究了隧洞施工對(duì)邊坡的影響及邊坡施工對(duì)隧洞圍巖穩(wěn)定性的影響;(3)考慮隧洞進(jìn)口圍巖與邊坡的三維效應(yīng)及相應(yīng)的動(dòng)態(tài)施工過程,研究了隧洞圍巖與邊坡體系穩(wěn)定性的時(shí)空演化特征;(4)通過擬定多個(gè)隧洞進(jìn)洞方案,研究了隧洞圍巖與邊坡相互作用體系下的進(jìn)洞順序。(3)在總結(jié)不良地質(zhì)大斷面隧洞施工組織過程與施工技術(shù)的基礎(chǔ)上,研究了大斷面隧洞圍巖的力學(xué)行為,提出了隧洞合理的施工方法和斷層穿越順序。在隧洞I層開挖中,研究了左右兩幅開挖法和核心土開挖法下的圍巖力學(xué)行為,綜合考慮左右兩幅開挖法具有施工速率更快,工序更簡(jiǎn)單,塑性區(qū)分布范圍更小等特點(diǎn),建議選擇左右兩幅開挖法。在隧洞II、III層開挖中,對(duì)比研究了半幅薄層和半幅厚層開挖法下的圍巖力學(xué)行為,從結(jié)果來看,選擇薄層開挖方案更利于圍巖穩(wěn)定。結(jié)合數(shù)值模擬方法研究了不良地質(zhì)大斷面隧洞在順層開挖和逆層開挖方式對(duì)圍巖穩(wěn)定性的影響,通過探討不同穿越方式下的圍巖力學(xué)行為特征,提出了合理的不良地質(zhì)斷層穿越方式。在逆層開挖方式下,頂拱、底板和邊墻的變形程度更大,塑性破壞區(qū)范圍更廣,因此選擇順層開挖方式更有利于圍巖穩(wěn)定。(4)考慮隧洞施工過程信息的時(shí)變特性,探索了不良地質(zhì)段大斷面隧洞耦合施工進(jìn)度的實(shí)時(shí)安全分析方法。根據(jù)隧洞工程的二維設(shè)計(jì)信息和工程地質(zhì)信息,建立常規(guī)三維幾何模型(3D模型),以此為基礎(chǔ),考慮施工過程的進(jìn)度信息,利用4D信息建模技術(shù),建立隧洞施工期4D信息模型�；赟QL數(shù)據(jù)庫搜索引擎的強(qiáng)大搜索功能,快速找到隧洞工程信息改變區(qū)域在計(jì)算模型中對(duì)應(yīng)的單元,對(duì)ABAQUS數(shù)值計(jì)算軟件進(jìn)行二次開發(fā),自動(dòng)讀取單元的搜索結(jié)果,并對(duì)其力學(xué)參數(shù)進(jìn)行相應(yīng)修改,實(shí)現(xiàn)隧洞數(shù)值計(jì)算模型信息的實(shí)時(shí)動(dòng)態(tài)更新。利用參數(shù)反演技術(shù)將當(dāng)前的監(jiān)測(cè)信息與相應(yīng)部位的計(jì)算值進(jìn)行對(duì)應(yīng),從而實(shí)現(xiàn)4D監(jiān)測(cè)信息模型與4D仿真模型的耦合。通過數(shù)值的實(shí)時(shí)計(jì)算判定隧洞各部位的安全穩(wěn)定特征,從而及時(shí)判定施工方案的安全有效性和合理性,并對(duì)下一步的安全穩(wěn)定狀態(tài)進(jìn)行預(yù)測(cè)。
[Abstract]:The diversion tunnel of large hydropower projects are mostly shallow and large section tunnels, in the construction process, the construction and the safety of the tunnel and the inlet side of mutual influence, mutual restraint, once the engineering stability accident surrounding rock, not only caused loss of life and property of the construction personnel, but also seriously affect the construction schedule, so the stability of tunnel surrounding rock and slope the diversion tunnel construction of large hydropower station has been the focus of attention in the field of geotechnical engineering. For diversion tunnel of large hydropower station, considering the structural design and construction of tunnel slope and tunnel interaction is a complex process with many factors affecting an audience, no rules to follow, the engineering analogy, construction technology and safety and the bad geological tunnel section directly affects the overall progress of the project in the tunnel construction process, so it is necessary for the construction technology of large section tunnel adverse geological Study on rock mechanics and behavior characteristics, to guide the actual construction project. The combination of China's hydropower station as an example, by using the rock mechanics and numerical analysis techniques, through the analysis of the adverse geological section of tunnel surrounding rock and slope of the mechanical behavior of tunnel surrounding rock and slope, mechanism of action and tunnel construction technology, safety, reasonable construction method. The main research contents and results are as follows: (1) based on the engineering geological conditions and background, analysis of underground cavern with large cross section in advance support measures, shotcrete supporting mechanism and effect of arch and steel net supporting mechanism of forepoling mainly. The formation characteristics of improvement and advance support effect. Spraying mixed reinforcement of tunnel surrounding rock are supporting the surrounding rock, loading, reinforcing surrounding rock fill, covering the surface of surrounding rock, prevent loosening and force distribution etc., The shotcrete tunnel reinforcement can effectively control the deformation of surrounding rock, can effectively curb the development of plastic zone in rock mass, rock loose to prevent instability. To improve the spray layer thickness can effectively reduce the tunnel top arch plastic zone, but the thickness is too large may cause the arch foot of the plastic zone due to stress concentration increases with the higher grade, the concrete spray layer as material for limiting the rock arch deformation has certain effect, but the effect is not obvious. (2) summarizes the tunnel surrounding rock slope system type and mechanical model, considering the tunnel slope coupling mechanism, in-depth study of the influence on the slope and tunnel construction slope construction on tunnel stability, discusses the tunnel surrounding rock and slope stability of the system evolution, and puts forward the reasonable hole sequence. The specific content involves four aspects: (1) to investigate the tunnel surrounding rock imports With slope interaction in parallel, orthogonal and oblique three system types, a geomechanical model is established accordingly, and discussed the slope and tunnel deformation interaction of sliding type, shear type, disturbance type and slip shear composite type several mechanical models; (2) considering the tunnel surrounding rock slope orthogonal import the role of the system, in-depth study of the influence on the slope of the tunnel construction and construction of the slope of the tunnel surrounding rock's stability; (3) considering the three-dimensional effects of tunnel surrounding rock and slope and the corresponding dynamic construction process of tunnel surrounding rock and slope stability of space-time evolution characteristics; (4) through the development of multiple hole tunnel study on the scheme, tunnel and slope interaction system under the hole in order. (3) based on summarizing the process and construction technology of large section tunnel construction geological bad organization, study the surrounding rock of large section tunnel. The mechanical behavior, put forward the construction method and the reasonable order of crossing tunnel in fault. In the I layer in the excavation of tunnel surrounding rock, study on mechanical behavior of about two amplitude excavation method and core soil excavation method, considering about two pieces of excavation method has the construction speed is faster, simpler process, plastic zone distribution range etc. about two pieces of advice, selection of excavation method in tunnel. II, III layer excavation, a comparative study of the half and half thin thick layer excavation of rock mechanical behavior under the law, from the results, the excavation scheme selection layer is more conducive to the stability of the surrounding rock. Based on the adverse geological tunnel large section excavation method for inverse effect the stability of the surrounding rock in the bedding excavation and numerical simulation method, the mechanical behavior of surrounding rock through the characteristics of different modes, put forward reasonable adverse geological fault crossing mode. In the inverse layer excavation method, arch, The degree of deformation of the base plate and the side wall is bigger, plastic zone range, so the choice of bedding excavation method is more conducive to the stability of the surrounding rock. (4) considering the tunnel construction process information time-varying, explore a real-time security analysis method of unfavorable geological section of large section tunnel coupling. According to the construction schedule of tunnel engineering the two-dimensional design information and engineering geological information, establish regular three-dimensional geometric model (3D model), on the basis of considering the progress of information construction process, using 4D modeling technology of information, establish 4D information model of tunnel construction period. The powerful search function of SQL database based on search engine, quickly find the information in the area of tunnel engineering change calculation model the corresponding unit of ABAQUS numerical calculation software development of two times, the automatic reading unit of the search results, and corresponding modification of the mechanical parameters to achieve the numerical model of tunnel Real time dynamic updating of the information. Using the parameter inversion calculation of monitoring information of current and the corresponding parts of the corresponding value, so as to realize the coupling of 4D monitoring information model and 4D simulation model. Through the numerical calculation to determine the safety and stability of the real-time characteristics of various parts of the tunnel, so as to timely determination of construction scheme is safe and effective and reasonable, and to predict the stability of the next step.

【學(xué)位授予單位】：天津大學(xué)
【學(xué)位級(jí)別】：博士
【學(xué)位授予年份】：2015
【分類號(hào)】：TV554
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本文編號(hào)：1563635