【摘要】：青島市是我國(guó)國(guó)家沿海重要的中心城市和濱海度假旅游城市,國(guó)際性港口城市。伴隨著青島市的飛速發(fā)展,需要建設(shè)大量的城市地下鐵道以緩解日益緊張的交通狀況,青島地區(qū)的"上軟下硬"地層對(duì)于地鐵隧道修建理論和技術(shù)提出了新的挑戰(zhàn),鑒于青島地區(qū)特有的地層,以往的的理論和其他城市工程經(jīng)驗(yàn)并不能對(duì)青島地鐵的修建提供有效的建議,因此有必要針對(duì)青島地鐵隧道穩(wěn)定性和支護(hù)設(shè)計(jì)進(jìn)行專門的研究。本文以青島R3線為工程背景,基于R3線某區(qū)間沿線地質(zhì)情況及現(xiàn)有隧道結(jié)構(gòu)形式,利用強(qiáng)度折減法計(jì)算洞室圍巖有支護(hù)和無(wú)支護(hù)情況下的穩(wěn)定性,并基于安全系數(shù)對(duì)現(xiàn)有初期支護(hù)形式進(jìn)行了優(yōu)化,本文主要完成了以下工作:1.簡(jiǎn)要地介紹了巖土工程數(shù)值計(jì)算中常用的M-C本構(gòu)、D-P本構(gòu)及MCC本構(gòu)模型,介紹了強(qiáng)度折減法基本原理、失穩(wěn)判據(jù)及其地下工程中安全系數(shù)的定義。2.采用有限元軟件ABAQUS中內(nèi)置的D-P本構(gòu)模型,利用強(qiáng)度折減法對(duì)青島R3線某區(qū)間內(nèi)Ⅲ級(jí)至Ⅵ級(jí)圍巖下1m至20m埋深下的洞室穩(wěn)定性進(jìn)行了計(jì)算分析,得出了該區(qū)間內(nèi)開挖淺埋隧道時(shí)圍巖穩(wěn)定性的空間分布:隨著上覆巖層厚度的增加,圍巖的穩(wěn)定性呈現(xiàn)出先增加后減少的過(guò)程,還得出了上軟下硬地層中圍巖失穩(wěn)而產(chǎn)生破壞形式及塑性區(qū)分布。3.采用有限元軟件ABAQUS中內(nèi)置的D-P本構(gòu)模型,利用強(qiáng)度折減法計(jì)算了現(xiàn)有初期支護(hù)形式在Ⅲ級(jí)至Ⅵ級(jí)圍巖在對(duì)圍巖穩(wěn)定性的加強(qiáng)作用,基于圍巖安全系數(shù)對(duì)現(xiàn)有區(qū)間地鐵隧道初期支護(hù)形式進(jìn)行了評(píng)價(jià),認(rèn)為目前采用的初期支護(hù)過(guò)強(qiáng),具有可優(yōu)化的空間。提出了優(yōu)化后的初期支護(hù)形式,并對(duì)優(yōu)化后的初期支護(hù)形式計(jì)算了圍巖安全系數(shù),保證了優(yōu)化設(shè)計(jì)的安全性。最后基于地層-結(jié)構(gòu)法計(jì)算了優(yōu)化初期支護(hù)后二次襯砌的安全系數(shù),計(jì)算結(jié)果表明:優(yōu)化設(shè)計(jì)不僅可以保持圍巖具有足夠的穩(wěn)定性,還能使隧道支護(hù)結(jié)構(gòu)在使用年限內(nèi)具有足夠的安全裕度保證正常使用。
[Abstract]:Qingdao is an important coastal city and an international port city. With the rapid development of Qingdao, it is necessary to build a large number of urban underground railways to ease the increasingly tense traffic situation. The "upper soft and hard" strata in Qingdao area pose new challenges to the theory and technology of subway tunnel construction. In view of the unique strata in Qingdao area, previous theories and other urban engineering experiences can not provide effective suggestions for the construction of Qingdao subway, so it is necessary to study the stability and support design of Qingdao subway tunnel. Taking Qingdao R3 line as the engineering background, based on the geological conditions along a certain section of the R3 line and the existing tunnel structure, the stability of the surrounding rock of the cavern with or without support is calculated by using the strength reduction method. And based on the safety factor to optimize the existing initial support form, this paper mainly completed the following work: 1. This paper briefly introduces the M-C constitutive D-P constitutive model and MCC constitutive model commonly used in numerical calculation of geotechnical engineering, and introduces the basic principle of strength reduction method, the instability criterion and the definition of safety factor in underground engineering. By using the D-P constitutive model built in the finite element software ABAQUS, the stability of the cavern under the buried depth of 1m to 20m is calculated and analyzed by using the strength reduction method in a certain section of the R3 line in Qingdao. The spatial distribution of surrounding rock stability during excavation of shallow tunnel in this section is obtained. With the increase of overlying rock thickness, the stability of surrounding rock presents the process of first increasing and then decreasing. The failure form of surrounding rock and the distribution of plastic zone in the upper soft and hard strata are also obtained. By using the D-P constitutive model built in the finite element software ABAQUS and using the strength reduction method, the strengthening effect of the existing initial supporting forms on the stability of surrounding rock in grade 鈪，

本文編號(hào)：2192897