本文選題：淺埋段隧道 + 雙側(cè)壁��； 參考：《華南理工大學(xué)》2015年碩士論文

【摘要】：隧道洞口淺埋段一般巖體破碎,穩(wěn)定性差,施工風(fēng)險(xiǎn)高,大斷面隧道一般均采用雙側(cè)壁導(dǎo)坑法開(kāi)挖,以控制圍巖變形與松弛,確保隧道整體穩(wěn)定與支護(hù)受力安全。雙側(cè)壁導(dǎo)坑法首先源自德國(guó),曾在德國(guó)地鐵中成功應(yīng)用,目前是我國(guó)在淺埋地形、軟弱地層中修建大斷面地下工程時(shí)普遍采用的一種工法,已經(jīng)在公路、鐵路、城市地鐵隧道建設(shè)中獲得廣泛應(yīng)用,積累了大量實(shí)踐經(jīng)驗(yàn)。盡管如此,我國(guó)在采用雙側(cè)壁導(dǎo)坑法進(jìn)行洞口淺埋段施工時(shí)仍出現(xiàn)了許多安全事故,如隧道冒頂坍塌、掉塊、噴射混凝土開(kāi)裂、錨桿失效、地表開(kāi)裂與下沉、鋼拱架嚴(yán)重扭曲變形等。這些安全事故的發(fā)生,一方面與施工管理與安全措施不到位有關(guān),另外一方面則與雙側(cè)壁導(dǎo)坑法的工藝流程與標(biāo)準(zhǔn)不統(tǒng)一有密切關(guān)系。本文結(jié)合工程實(shí)例中大斷面扁平隧道的實(shí)際洞形大小與圍巖狀況,采用大型巖土工程軟件FLAC3D進(jìn)行數(shù)值模擬,重點(diǎn)對(duì)中隔壁曲率半徑、側(cè)壁導(dǎo)坑的大小(中隔壁位置)、中導(dǎo)洞分塊大小等三個(gè)關(guān)鍵工序參數(shù)進(jìn)行平面應(yīng)變模式下的標(biāo)準(zhǔn)化施工研究,分別將中隔壁曲率半徑分為R=11.6m∠52°、R=5.76m∠106°、R=5.46m∠104°以及R=+∞∠180。四種工況；將側(cè)壁導(dǎo)坑的大小(中隔壁位置)分為L(zhǎng)=1/3B、L=1/4B和L=1/5B三種工況；將中導(dǎo)洞分塊大小分為h1=1/2H(兩臺(tái)階)、h,=1/3H(兩臺(tái)階)、h1=3/5H(跟最大斷面處、兩臺(tái)階相對(duì)應(yīng))、h1=h2=1/3H(三臺(tái)階)四種工況進(jìn)行仿真模擬分析,通過(guò)對(duì)圍巖沉降、水平位移、圍巖塑性區(qū)、圍巖最大壓應(yīng)力、圍巖最大拉應(yīng)力、初期支護(hù)最大壓應(yīng)力、初期支護(hù)最大拉應(yīng)力七個(gè)指標(biāo)的比較進(jìn)行綜合必選,確定最優(yōu)的參數(shù)取值,從而提出雙側(cè)壁導(dǎo)坑法標(biāo)準(zhǔn)化施工方案。
[Abstract]:In order to control the deformation and relaxation of surrounding rock and to ensure the overall stability and safety of the tunnel, large section tunnels are generally excavated by the method of double-sidewall diversion pit with poor stability and high construction risk. The method of double-sidewall pit guide first originated in Germany and was successfully applied in the German subway. At present, it is commonly used in the construction of large cross-section underground projects in shallow buried terrain and soft strata in China. It has already been used in highways and railways. Urban subway tunnel construction has been widely used, accumulated a lot of practical experience. However, there are still many safety accidents such as tunnel roof collapse, falling block, shotcrete cracking, bolt failure, surface cracking and subsidence, when using double-side wall guide pit method to carry out shallow burying section construction of the tunnel, such as tunnel roof collapse, block fall, shotcrete cracking, bolt failure, ground surface cracking and subsidence, etc. Severe distortion of steel arch, etc. The occurrence of these safety accidents is related to the lack of construction management and safety measures on the one hand, and to the disunity of the technological process and standard of the double-sidewall guide pit method on the other hand. Combined with the actual hole size and surrounding rock condition of large section flat tunnel in engineering example, the numerical simulation of large geotechnical engineering software FLAC3D is carried out in this paper, with emphasis on the radius of curvature of the middle and next section. Three key process parameters, namely, the size of the sidewall guide pit (the middle adjoining position and the block size of the middle guide tunnel), are studied in the standardized construction under the plane strain mode. The radius of the curvature of the middle wall is divided into two categories: r = 11.6m ~ 52 擄, R ~ (5.76 m) ~ 106 擄~ (?) ~ (5.46m) ~ 104 擄and R = 鈭，

本文編號(hào)：2004614