本文選題：薄層破壞硬質(zhì)巖　切入點：離散元法　出處：《西南交通大學》2015年碩士論文

【摘要】：本文主要研究內(nèi)容依托于貴陽龍洞堡機場隧道項目,該隧道穿越薄層破碎硬質(zhì)巖地層,圍巖中發(fā)育有較多層理、節(jié)理等結(jié)構(gòu)面,而圍巖受擾動后很容易沿結(jié)構(gòu)面發(fā)生位移或破壞。本文采用3DEC離散元法,主要研究了隧道開挖對地表沉降和上部建筑結(jié)構(gòu)的影響。由本文研究內(nèi)容,可以得出如下結(jié)論：(1)在薄層破碎硬質(zhì)巖體中,隧道施工引起的地表沉降的分布規(guī)律除受施工因素的影響外,同時還受巖塊性質(zhì)、結(jié)構(gòu)面力學性質(zhì)和分布形式等環(huán)境的影響,其中結(jié)構(gòu)面的影響主要有：由于結(jié)構(gòu)面強度和穩(wěn)定性要比巖石低很多,隧道開挖后容易沿薄弱結(jié)構(gòu)面發(fā)生變形或破壞；地層層理的傾角不同,則沉降槽中心相對于隧道中心的位置也不同；節(jié)理通縫分布時,地表沉降會在洞周附近節(jié)理面對應(yīng)地表處產(chǎn)生很大的突變,而節(jié)理錯縫分布時,地表沉降變化規(guī)律整體上與連續(xù)介質(zhì)中很相似,地表沉降橫向分布曲線大致可以用正態(tài)曲線描述,符合Peck公式,地表沉降沿縱向大致分為三個區(qū)一一前期沉降區(qū)、快速沉降區(qū)以及沉降收斂區(qū)。(2)隧道開挖引起的地表位移,如地表均勻沉降、地表傾斜、地表曲率和地表水平位移等,都會導(dǎo)致結(jié)構(gòu)的變形和應(yīng)力重分布,影響結(jié)構(gòu)的穩(wěn)定性,嚴重的導(dǎo)致結(jié)構(gòu)開裂,甚至破壞。建筑結(jié)構(gòu)的破壞模式與建筑的結(jié)構(gòu)類型、處于沉降槽的位置等有關(guān)。為了保證建筑結(jié)構(gòu)正常使用和防止結(jié)構(gòu)破壞,一些建筑相關(guān)規(guī)范給出了建筑結(jié)構(gòu)的變形和應(yīng)力的控制標準,而我國城市地鐵項目中通常30mm的地表沉降作為控制標準,但是此標準是根據(jù)工程經(jīng)驗得出的,并且有一定的適用范圍,針對具體工程我們可以通過計算確定地表沉降控制標準。(3)基于龍洞堡機場隧道項目,運用3DEC離散元軟件研究了隧道開挖過程對高架橋和地下停車場的影響。一般來說,建筑基礎(chǔ)距離沉降槽中心的位置越近受到的影響越大；相對CRD法,雙側(cè)壁導(dǎo)坑法對隧道上部結(jié)構(gòu)影響更��；輔助工法能控制地層位移和減小對結(jié)構(gòu)的影響。具體工程中一般應(yīng)根據(jù)工程經(jīng)驗、數(shù)值模擬或模型實驗等方法確定施工措施,并根據(jù)現(xiàn)場監(jiān)測結(jié)果及時調(diào)整。(4)基于龍洞堡機場隧道工程,經(jīng)計算將隧道開挖下穿高架橋的過程中地表沉降的控制標準定為25mm。結(jié)合數(shù)值模擬結(jié)果和現(xiàn)場實測數(shù)據(jù)分析,經(jīng)驗算當采用設(shè)計要求進行隧道施工時,地表沉降、結(jié)構(gòu)變形和應(yīng)力均可滿足控制標準。
[Abstract]:The main research content of this paper is based on the Longdongbao Airport Tunnel Project in Guiyang, which passes through thin layer broken hard rock strata, and there are more bedding and joints in the surrounding rock.But the surrounding rock is easy to displace or destroy along the structure surface after disturbance.In this paper, 3DEC discrete element method is used to study the influence of tunnel excavation on surface settlement and superstructure.From the research contents of this paper, we can draw the following conclusion: (1) in thin layer broken hard rock mass, the distribution law of ground subsidence caused by tunnel construction is not only affected by construction factors, but also affected by the properties of rock block.The influence of mechanical properties and distribution form of structural plane is mainly as follows: because the strength and stability of structural plane are much lower than that of rock, the tunnel is prone to deformation or failure along the weak structural plane after excavation;If the dip angle of stratigraphic strata is different, the position of the center of the subsidence trough relative to the center of the tunnel will be different, and when the joint joint is distributed, the ground subsidence will produce a very big mutation in the joint face of the surface near the hole, and when the joint is staggered,The variation law of surface subsidence is similar to that in continuous medium, and the lateral distribution curve of surface subsidence can be described by normal curve, which accords with Peck formula.The surface displacement caused by the excavation of the tunnel, such as uniform settlement, slope, curvature and horizontal displacement, will lead to the deformation and stress redistribution of the structure, which will affect the stability of the structure.Serious structural cracking, or even damage.The failure mode of building structure is related to the type of structure and the position of settlement tank.In order to ensure the normal use of the building structure and prevent the structural damage, some building codes give the control standard of the deformation and stress of the building structure, and the ground subsidence of 30mm is usually used as the control standard in the urban subway projects in China.However, this standard is based on engineering experience and has a certain scope of application. For specific projects, we can determine the control standard of surface subsidence by calculation. 3) based on the Longdongbao Airport Tunnel Project.The influence of tunnel excavation on viaduct and underground parking lot is studied by 3DEC discrete element software.Generally speaking, the closer the position of building foundation to the center of settlement trough is, the greater the influence is; compared with the CRD method, the double-sidewall method has less influence on the superstructure of tunnel; the auxiliary method can control the displacement of the stratum and reduce the influence on the structure.Construction measures should be determined according to engineering experience, numerical simulation or model experiment, and adjusted timely according to site monitoring results.) based on Longdongbao Airport Tunnel Project,Through calculation, the control standard of ground subsidence in the course of tunnel excavation through viaduct is determined to be 25mm.Based on the analysis of the numerical simulation results and the field measured data, when the design requirements are adopted for tunnel construction, the ground subsidence, structural deformation and stress can meet the control standards.
【學位授予單位】：西南交通大學
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：U451;U455

【相似文獻】

相關(guān)期刊論文 前2條

1 張國翠;;硬質(zhì)巖開挖棄料加工的人工粗骨料的質(zhì)量控制[J];水利水電技術(shù);2009年10期

2 ;[J];;年期

相關(guān)碩士學位論文 前1條

1 徐燈飛;薄層破碎硬質(zhì)巖隧道（群）施工對上部關(guān)鍵結(jié)構(gòu)的影響研究[D];西南交通大學;2015年

，

本文編號：1709456