發(fā)布時(shí)間：2018-11-25 10:47

【摘要】：本文依托麻崖子隧道，主要研究III、IV、V級(jí)圍巖隧道結(jié)構(gòu)受力特性與安全性評(píng)價(jià)： 首先，通過現(xiàn)場(chǎng)的地質(zhì)預(yù)報(bào)與地質(zhì)素描，認(rèn)識(shí)不同級(jí)別圍巖性質(zhì)，成功預(yù)報(bào)出Ⅴ級(jí)圍巖地段的斷層破碎帶和涌水地質(zhì)災(zāi)害；介紹規(guī)范中BQ圍巖分級(jí)，BQ分級(jí)法關(guān)鍵在于得出圍巖的單軸飽和抗壓強(qiáng)度RC與圍巖的完整性系數(shù)KV，借助現(xiàn)場(chǎng)試驗(yàn)室測(cè)定巖石單軸抗壓強(qiáng)度，通過統(tǒng)計(jì)裸露掌子面突起部位得到節(jié)理數(shù)，介紹BQ分級(jí)方法，使我們能迅速準(zhǔn)確地分辨圍巖的級(jí)別，及時(shí)調(diào)整開挖與支護(hù)參數(shù)。 其次，，通過對(duì)III、IV、V級(jí)圍巖地段各選擇5組斷面進(jìn)行周邊收斂與拱頂下沉測(cè)試得出：其變形值隨圍巖級(jí)別的增大而增大，收斂時(shí)間與巖性、節(jié)理等因素有關(guān)；以極限位移值與位移速率為標(biāo)準(zhǔn)對(duì)圍巖變形做出評(píng)判，判定隧道的安全性；基于監(jiān)控量測(cè)數(shù)據(jù)運(yùn)用位移反分析得出圍巖的力學(xué)參數(shù)，并結(jié)合設(shè)計(jì)規(guī)范給出的圍巖參數(shù)，從而確定有限元模擬時(shí)所用圍巖參數(shù)。 再次，通過在IV、V級(jí)圍巖地段埋設(shè)測(cè)試元件（包括壓力盒、鋼筋計(jì)、表面應(yīng)變計(jì)和混凝土應(yīng)變計(jì)等），對(duì)圍巖和隧道結(jié)構(gòu)受力進(jìn)行量測(cè)試驗(yàn)；基于對(duì)測(cè)試結(jié)果的對(duì)比與分析，找出隧道初支與二襯分擔(dān)的荷載比例，隧道襯砌內(nèi)力變化規(guī)律、受力狀況和受力薄弱部位；通過受力分析和監(jiān)控量測(cè)，對(duì)支護(hù)時(shí)機(jī)的選擇做出判斷；對(duì)V級(jí)隧道的圍巖與初支、初支與復(fù)拱、復(fù)拱與二襯分別所承擔(dān)的荷載比進(jìn)行了對(duì)比。 最后，通過結(jié)合反位移法得出的參數(shù)和規(guī)范規(guī)定的參數(shù)，得出各級(jí)圍巖的模擬參數(shù)。使用有限元對(duì)其結(jié)構(gòu)與圍巖進(jìn)行整體模擬，得出位移云圖和應(yīng)力云圖。利用提取的拱頂下沉值、周邊收斂值、錨桿軸力圖與現(xiàn)場(chǎng)測(cè)試進(jìn)行校核，來分析變形趨；分別求出各級(jí)圍巖中，各施工工法所引起的周邊收斂與拱頂下沉的比例，找出各級(jí)圍巖隧道開挖中最不利工序；提取襯砌軸力、彎矩、錨桿軸力、初支剪力，求得初支與襯砌的安全系數(shù)，進(jìn)而評(píng)價(jià)隧道的安全性。
[Abstract]:Based on Mayazi Tunnel, this paper mainly studies the structural stress characteristics and safety evaluation of III,IV,V class surrounding rock tunnel. Firstly, through the field geological prediction and geological sketch, we know the nature of different grade surrounding rock. The fault fracture zone and water gushing geological hazard of grade V surrounding rock are successfully predicted. This paper introduces the classification of BQ surrounding rock in the code. The key point of BQ classification method is to obtain the uniaxial saturated compressive strength of surrounding rock RC and the integrality coefficient of surrounding rock KV, to measure the uniaxial compressive strength of rock with the help of field laboratory. By counting the joints in the protruding part of the exposed face, the paper introduces the BQ classification method, which enables us to quickly and accurately distinguish the grade of surrounding rock and adjust the excavation and support parameters in time. Secondly, through the test of peripheral convergence and arch roof subsidence of 5 groups of sections selected for III,IV,V grade surrounding rock, it is concluded that the deformation value increases with the increase of surrounding rock level, and the convergence time is related to lithology, joints and other factors; Based on the limit displacement value and displacement rate, the deformation of surrounding rock is evaluated and the safety of tunnel is determined. Based on the monitoring data, the mechanical parameters of the surrounding rock are obtained by using the displacement back analysis, and the parameters of the surrounding rock are given in the design code, so as to determine the surrounding rock parameters used in the finite element simulation. Thirdly, the test elements (including pressure box, steel bar gauge, surface strain gauge and concrete strain gauge) are embedded in the surrounding rock of IV,V class to measure the stress of surrounding rock and tunnel structure. Based on the comparison and analysis of the test results, the paper finds out the load ratio of the first branch and the second lining, the law of the change of the tunnel lining internal force, the force condition and the weak position of the tunnel lining. Through the force analysis and monitoring measurement, the choice of supporting opportunity is judged, and the load ratio of surrounding rock and initial branch, initial support and double arch, double arch and second lining of V class tunnel are compared. Finally, the simulation parameters of surrounding rock at all levels are obtained by combining the parameters obtained by the reverse displacement method and the parameters specified in the specifications. The finite element method is used to simulate the structure and surrounding rock, and the displacement cloud map and stress cloud map are obtained. The deformation trend is analyzed by using the extracted dome subsidence value, peripheral convergence value, anchor shaft force and field test. The ratio of circumjacent convergence and dome subsidence caused by each construction method in surrounding rock of all levels is calculated, and the most unfavorable procedure in excavation of surrounding rock tunnel at all levels is found out. The axial force of lining, moment of bending, axial force of anchor rod and shear force of initial support are extracted, and the safety factors of initial support and lining are obtained, and the safety of tunnel is evaluated.
【學(xué)位授予單位】：長(zhǎng)安大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2014
【分類號(hào)】：U452.12

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