本文選題：軟質(zhì)片巖 + 蠕變�。� 參考：《華東交通大學》2014年碩士論文

【摘要】：隨著國家基礎(chǔ)建設(shè)不斷發(fā)展，越來越多的公路、鐵路向山區(qū)延伸，為了縮短里程和保護沿線自然環(huán)境，隧道便成為其主要的設(shè)計形式之一。由于地質(zhì)條件的復雜性，使得現(xiàn)有的隧道工程技術(shù)尚不能完全解決工程中所遇問題，例如高地應力、仰拱隆起及軟巖大變形等問題。目前，軟巖大變形規(guī)律已經(jīng)成為軟巖隧道建設(shè)中研究的熱點問題，在軟巖隧道工程施工過程中控制圍巖大變形往往是軟巖隧道修建成功的關(guān)鍵。由于軟巖隧道圍巖變形特征的復雜性，使得軟巖隧道大變形控制技術(shù)仍然處于爭議和探索階段。本文以某軟質(zhì)片巖隧道為工程依托，對軟質(zhì)片巖隧道圍巖變形規(guī)律及其大變形控制技術(shù)進行系統(tǒng)的分析。全文的主要研究內(nèi)容和結(jié)論有： （1）在分析軟質(zhì)片巖的巖性、工程力學特性及軟質(zhì)片巖受力變形特點的基礎(chǔ)上，研究軟質(zhì)片巖隧道圍巖大變形影響因素及其大變形特征。 （2）根據(jù)前人的研究發(fā)現(xiàn)，軟巖具有明顯的流變特性，且其流變主要表現(xiàn)為蠕變變形；本文在分析了軟巖的蠕變變形規(guī)律和本構(gòu)模型的基礎(chǔ)上，結(jié)合該隧道軟質(zhì)片巖圍巖的變形規(guī)律，發(fā)現(xiàn)Burgers蠕變本構(gòu)模型較為符合軟質(zhì)片巖的變形特性。 （3）鑒于FLAC3D數(shù)值模擬軟件在巖土工程上的應用及其在大變形分析上的優(yōu)勢，本文采用FLAC3D軟件對軟質(zhì)片巖隧道進行數(shù)值模擬；由于軟質(zhì)片巖隧道結(jié)構(gòu)面和節(jié)理裂隙發(fā)育，加上施工擾動作用及遇水軟化等特點，將所選取的模擬區(qū)段圍巖簡化為各向同性材料。 （4）在對所選取的五種開挖工況分別進行模擬后發(fā)現(xiàn)：等臺階（5.0m）長度下二臺階法和三臺階法開挖對圍巖的變形和應力影響較��；超短（2.5m）臺階開挖，，能有效減小圍巖的應力和變形；預留核心土能有效控制掌子面和拱頂?shù)淖冃�，增強掌子面的穩(wěn)定性，但其對拱頂部位的塑性區(qū)影響較大。 （5）對超前小導管模擬發(fā)現(xiàn)：超前支護能使拱頂部位形成一個承載拱，有效的控制拱頂?shù)淖冃危欢诔靶Ч苁┕ぶ懈淖冃Ч艿膬A角雖對圍巖的穩(wěn)定性起到一定的作用，但其效果并不明顯。對系統(tǒng)錨桿的模擬發(fā)現(xiàn)：錨桿的長度對于其在軟巖中的作用是非常明顯的，選擇適當長度的錨桿能起到經(jīng)濟高效的效果。 （6）蠕變作用是解釋軟巖隧道圍巖與支護結(jié)構(gòu)相互作用的重要理論，本文從蠕變理論著手，并通過現(xiàn)場隧道圍巖和不同支護構(gòu)件的長期受力變形監(jiān)測，初步分析了支護結(jié)構(gòu)初期的變形受力特點及其受巖體作用下的長期穩(wěn)定狀態(tài)。
[Abstract]:With the continuous development of national infrastructure, more and more highways and railways extend to mountainous areas. In order to shorten mileage and protect the natural environment along the road, tunnel becomes one of its main design forms. Due to the complexity of geological conditions, the existing tunnel engineering technology can not completely solve the problems encountered in the engineering, such as high ground stress, inverted arch uplift and large deformation of soft rock, etc. At present, the law of large deformation of soft rock has become a hot issue in the construction of soft rock tunnel. Controlling the large deformation of surrounding rock in the construction of soft rock tunnel is the key to the success of soft rock tunnel construction. Due to the complexity of surrounding rock deformation characteristics of soft rock tunnel, the large deformation control technology of soft rock tunnel is still in the stage of controversy and exploration. Based on a soft schist tunnel, the deformation law of surrounding rock and its large deformation control technology in soft schist tunnel are systematically analyzed in this paper. The main contents and conclusions of this paper are as follows: 1) based on the analysis of the lithology, engineering mechanical properties and deformation characteristics of soft schist, the factors affecting the large deformation of surrounding rock in soft schist tunnel and the characteristics of large deformation are studied. 2) based on the previous studies, it is found that soft rock has obvious rheological characteristics, and its rheology is mainly characterized by creep deformation. In this paper, the creep deformation law and constitutive model of soft rock are analyzed. According to the deformation law of soft schist rock surrounding rock in this tunnel, it is found that the Burgers creep constitutive model accords with the deformation characteristics of soft schist rock. 3) in view of the application of FLAC3D numerical simulation software in geotechnical engineering and its advantage in large deformation analysis, the soft schist tunnel is numerically simulated by FLAC3D software, because of the development of structural plane and joint fracture of soft schist tunnel, Combined with the characteristics of construction disturbance and water softening, the selected surrounding rock of the simulated section is simplified as isotropic material. 4) after simulating the five kinds of excavation conditions, it is found that two step method and three step method excavation have little influence on the deformation and stress of surrounding rock under equal step length (5.0 m), and ultra-short excavation of 2.5 m) step excavation can effectively reduce the stress and deformation of surrounding rock. The reserved core soil can effectively control the deformation of palm surface and dome and enhance the stability of metacarpal surface, but it has a great influence on the plastic zone of the crown. 5) it is found that the advance support can form a bearing arch at the top of the arch, and control the deformation of the arch effectively, while changing the inclination of the small pipe in the construction of the leading small conduit plays a certain role in the stability of the surrounding rock. But its effect is not obvious. It is found that the length of the bolt is very obvious to the soft rock, and the choice of the appropriate length of the bolt can play an economic and efficient effect. (6) creep is an important theory to explain the interaction between surrounding rock and supporting structure in soft rock tunnel. The deformation and stress characteristics of the supporting structure at the initial stage and the long-term stable state under the action of the rock mass are preliminarily analyzed.
【學位授予單位】：華東交通大學
【學位級別】：碩士
【學位授予年份】：2014
【分類號】：U455.49

【參考文獻】

相關(guān)期刊論文 前1條

1 劉浴沂;隔河巖石牌頁巖工程力學特性研究[J];長江科學院院報;1993年04期

本文編號：1935718