發(fā)布時(shí)間：2018-01-03 19:10

  本文關(guān)鍵詞：薄層破碎硬質(zhì)巖隧道群施工的壓力拱效應(yīng)及荷載理論模型研究　出處：《西南交通大學(xué)》2014年碩士論文　論文類型：學(xué)位論文

  更多相關(guān)文章： 隧道工程 壓力拱 荷載理論模型 破碎圍巖 離散元法

【摘要】：我國(guó)交通建設(shè)的蓬勃發(fā)展,為隧道及地下工程的發(fā)展帶來(lái)了機(jī)遇與挑戰(zhàn)。薄層破碎硬質(zhì)巖多分布在沉積巖及巖溶地區(qū),我國(guó)云貴川地區(qū)的地下工程施工中將可能遇見這種特殊的圍巖,然而目前對(duì)其工程特性開展的研究并不多。本文采用離散元軟件,對(duì)該圍巖條件下的地下洞室開挖進(jìn)行數(shù)值分析研究,并通過(guò)一定的現(xiàn)場(chǎng)實(shí)測(cè)數(shù)據(jù)進(jìn)行驗(yàn)證,得出如下結(jié)論：(1)薄層破碎硬質(zhì)巖內(nèi)部貫通的層理與錯(cuò)開分布的節(jié)理這幾組軟弱結(jié)構(gòu)面決定了其主要的工程性質(zhì)：易于沿層理發(fā)生順層滑移：可以承受一定的彎矩作用；軟弱結(jié)構(gòu)面的變形將對(duì)整個(gè)地層產(chǎn)生最主要的影響。地下洞室開挖后,洞周的圍巖將由近及遠(yuǎn)的逐層張開、剝離變形。節(jié)理張開變形所引起的洞周收斂位移較順層滑移引起的變形位移量更大,但后者的影響范圍更廣。這兩種位移相互垂直,使得薄層破碎圍巖地下洞室開挖后位移云圖呈“十字形”分布,且“十字”偏斜的角度與貫通的層理面傾角相一致。(2)洞室埋深大于臨界埋深時(shí),薄層破碎硬質(zhì)巖地下洞室開挖后洞周圍巖將產(chǎn)生壓力拱效應(yīng)。提出以不同范圍內(nèi)的圍巖的切向應(yīng)力增加量與該路徑上圍巖總切向應(yīng)力增加量的比值來(lái)確定該范圍內(nèi)圍巖對(duì)壓力拱成拱作用的貢獻(xiàn),并據(jù)此劃分壓力拱效應(yīng)的主要區(qū)域界限。對(duì)比計(jì)算了不同傾角、不同結(jié)構(gòu)面參數(shù)下不同埋深、不同跨度的地下洞室開挖后洞周圍巖的壓力拱效應(yīng)：當(dāng)軟弱結(jié)構(gòu)面力學(xué)性質(zhì)遠(yuǎn)差于巖塊的力學(xué)性質(zhì)時(shí),軟弱結(jié)構(gòu)面的粘聚力和摩擦角對(duì)整體圍巖開挖后力學(xué)狀態(tài)影響不大；層理面傾角較緩時(shí),壓力拱高度隨層理面傾角的變化不明顯,當(dāng)層理面傾角超過(guò)某個(gè)閾值時(shí),壓力拱范圍隨層理面傾角的增大而顯著增加：隧道埋深大于臨界埋深時(shí),洞室埋深的增加對(duì)壓力拱范圍的影響不明顯；洞周壓力拱范圍與洞室跨度呈線性遞增關(guān)系。根據(jù)這些結(jié)論擬合出特定工況下的薄層破碎硬質(zhì)巖地下洞室開挖壓力拱高度公式。(3)考慮薄層破碎硬質(zhì)巖的特性修改了普氏塌落拱理論與巖柱理論使其更好的適用于該圍巖條件。發(fā)展了壓力拱承載結(jié)構(gòu)理論計(jì)算圍巖荷載的方法,并對(duì)比現(xiàn)行鐵路隧道設(shè)計(jì)規(guī)范、修正塌落拱理論與壓力拱承載結(jié)構(gòu)理論,提出各自的適用范圍。(4)結(jié)合貴陽(yáng)龍洞堡機(jī)場(chǎng)隧道的現(xiàn)場(chǎng)實(shí)測(cè)數(shù)據(jù)與離散元軟件數(shù)值模擬計(jì)算結(jié)果,分析該并行近接段施工的圍巖力學(xué)狀態(tài)。后行隧道的開挖將破壞先行隧道形成的壓力拱效應(yīng),形成聯(lián)合壓力拱或拱形梁效應(yīng),對(duì)圍巖受力狀態(tài)及地表沉降位移產(chǎn)生決定性影響。當(dāng)近接隧道中巖柱厚度小于8.5m時(shí),近接隧道間中巖柱可能發(fā)生失穩(wěn),應(yīng)予以注意并采取一定措施以避免發(fā)生事故。(5)通過(guò)數(shù)值模擬結(jié)果與現(xiàn)場(chǎng)實(shí)測(cè)數(shù)據(jù)、已有研究成果對(duì)比,表明離散元方法可以較為準(zhǔn)確地模擬薄層破碎硬質(zhì)圍巖條件的地下洞室開挖狀況。
[Abstract]:The vigorous development of China's transportation construction, brings opportunities and challenges for the development of tunnel and underground engineering. The thin broken hard rock distributed in sedimentary rock and karst area, Guizhou and Sichuan area in China during the construction of underground engineering can meet the special rock, however there is little research on the engineering characteristics of in this paper. Using the discrete element software, the surrounding rock of the underground cavern excavation is numerically analyzed, and verified by field test data, draw the following conclusions: (1) the thin broken hard rock bedding and staggered through internal distribution joints these groups of weak structure plane determines the main engineering properties: easy along the bedding slip layer: can be influnced by moment; weak structure surface deformation will have a main effect on the whole stratum. Underground excavation, tunnel The rock layer will open, the deformation of joints. Peeling from the near to the distant convergence around the tunnel caused by the displacement of deformation is along the displacement caused by the slip layer is larger, but the scope of the latter is wider. These two kinds of vertical displacement, the thin layer of broken surrounding rock of underground cavern excavation displacement was "cross" the distribution, consistent with the cross deflection angle and through the bedding plane angle. (2) the depth of the tunnel is larger than the critical depth, thin broken hard rock after excavation of underground cavern surrounding rock will produce pressure arch effect. The surrounding rock in different range of the tangential stress increases with the path the total amount of surrounding rock increase ratio to stress to determine the range of surrounding rock pressure arch effect, the main regional boundaries and accordingly divided into pressure arch effect. Compare the calculation of different angles, different structural plane parameters In different depth, the arch effect of the surrounding rock pressure of underground caverns of different span after excavation: when the mechanical properties of structural plane is far worse than the weak mechanical properties of rock, little weak structure of the cohesion and friction angle on the impact of the overall mechanical state of surrounding rock after excavation; bedding plane angle is gentle, the pressure arch height change with the bedding plane angle is not obvious, when the bedding angles exceeds a certain threshold, increasing the pressure arch with bedding angles and increase the buried depth of the tunnel is larger than the critical depth, the depth of the tunnel affected by the increase of pressure arch is not obvious; the tunnel pressure arch tunnel span range and linear the relationship between increasing. According to these conclusions fit thin specific conditions of underground cavern excavation of hard rock crushing pressure arch height formula. (3) considering the properties of thin broken hard rock modified collapsing arch theory and rock pillar The theory of making it better for the development of the surrounding rock. The rock pressure calculation method of load bearing arch structure theory, and compared to the existing railway tunnel design specification, revision of arch collapse theory and pressure bearing arch structure theory, put forward the application scope of each. (4) numerical simulated calculation results with measured data of tunnel and Guiyang Longdongbao Airport the discrete element software, analysis the parallel construction of the adjacent rock mechanics. After excavation tunnel will destroy the first tunnel formation pressure arch effect, the formation of joint pressure arch or arch effect on surrounding rock stress and surface subsidence displacement have a decisive impact. When approaching the tunnel rock pillar thickness is less than 8.5m, near the middle rock pillar between the tunnel instability may occur, should pay attention to them and take some measures to avoid the accident. (5) through the numerical simulation results and field measured data, The comparison of the existing research results shows that the discrete element method can accurately simulate the excavation condition of the underground cavern in the thin layer of hard rock.

【學(xué)位授予單位】：西南交通大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2014
【分類號(hào)】：U451.2

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本文編號(hào)：1375200