發(fā)布時(shí)間：2018-01-04 20:31

  本文關(guān)鍵詞：茅田界隧道變質(zhì)砂巖動(dòng)力響應(yīng)特性研究　出處：《華中科技大學(xué)》2015年碩士論文　論文類(lèi)型：學(xué)位論文

  更多相關(guān)文章： 變質(zhì)砂巖 動(dòng)力響應(yīng) 卸荷試驗(yàn) 光面爆破 數(shù)值模擬

【摘要】：深埋長(zhǎng)大的山嶺隧道,在爆破荷載作用下,掌子面附近圍巖會(huì)產(chǎn)生劇烈的振動(dòng),易誘發(fā)工程事故,影響工程的安全性。研究巖體的動(dòng)力響應(yīng)特征可以在一定程度上預(yù)測(cè)工程災(zāi)害,避免不必要的經(jīng)濟(jì)損失。本文以二廣高速公路茅田界隧道為工程依托,開(kāi)展變質(zhì)砂巖峰前卸圍壓及聲發(fā)射試驗(yàn),并采用ANSYS/LS-DYNA軟件進(jìn)行爆破荷載作用下的數(shù)值模擬工作,對(duì)茅田界隧道變質(zhì)砂巖的動(dòng)力響應(yīng)特性進(jìn)行分析研究。首先,本文簡(jiǎn)單闡述了巖石的爆破機(jī)理、巖體動(dòng)力擾動(dòng)特性及等效數(shù)值模擬的方法等基本內(nèi)容。結(jié)合峰前卸圍壓試驗(yàn),研究了茅田界隧道變質(zhì)砂巖破壞特征。試驗(yàn)結(jié)果表明:圍壓可以有效抑制巖樣的破壞,提高巖樣的承載力;高卸荷速率下巖樣的破壞存在突然性,巖樣表現(xiàn)出更強(qiáng)的脆性破壞特征,同時(shí)巖樣的極限儲(chǔ)能降低。其次,開(kāi)展掏槽孔塑性區(qū)擴(kuò)展的研究,確定掏槽孔合理的裝藥集度為0.54 kg/m,進(jìn)而確定茅田界隧道III級(jí)圍巖光面爆破的設(shè)計(jì)參數(shù)。通過(guò)定義不同初始時(shí)刻的荷載子步實(shí)現(xiàn)微差起爆的效果,驗(yàn)證了光面爆破參數(shù)的合理性。最后,采用ANSYS/LS-DYNA軟件,分析了茅田界隧道變質(zhì)砂巖動(dòng)力響應(yīng)的基本規(guī)律。數(shù)值模擬結(jié)果表明:質(zhì)點(diǎn)振動(dòng)方向與應(yīng)力波傳播方向一致時(shí),主頻要高于其他方向的振動(dòng)主頻,且主頻隨位移變化的靈敏度較低;質(zhì)點(diǎn)的峰值振速、質(zhì)點(diǎn)的峰值位移和拱頂?shù)谝恢鲬?yīng)力峰值均表現(xiàn)出隨著爆源距的增大而減小的特征;拱頂至邊墻底部的第一主應(yīng)力由主拉應(yīng)力向主壓應(yīng)力轉(zhuǎn)化;茅田界隧道III級(jí)圍巖的合理爆破進(jìn)尺為3~4 m;隧道掌子面1 m范圍內(nèi)的巖體動(dòng)力響應(yīng)最為敏感。
[Abstract]:Deep buried mountain tunnel, under blasting load, surrounding rock near the face of the palm will produce violent vibration, easy to cause engineering accidents. Study on dynamic response characteristics of rock mass can predict engineering disasters to a certain extent and avoid unnecessary economic losses. This paper relies on Maotian Tunnel of Er-Guangzhou Expressway. The tests of unloading confining pressure and acoustic emission in front of metamorphic sandstone are carried out, and the numerical simulation work under blasting load is carried out by using ANSYS/LS-DYNA software. The dynamic response characteristics of metamorphic sandstone in Maotian Tunnel are analyzed and studied. Firstly, the blasting mechanism of rock is briefly described in this paper. Dynamic disturbance characteristics of rock mass and equivalent numerical simulation method. Combined with pre-peak unloading confining pressure test. The failure characteristics of metamorphic sandstone in Maotian Tunnel are studied. The experimental results show that confining pressure can effectively restrain the damage of rock samples and improve the bearing capacity of rock samples. At high unloading rate, the failure of rock samples is sudden, the rock samples show a stronger brittle failure characteristics, and the limit energy storage of rock samples is reduced. Secondly, the study on the expansion of cut plastic zone is carried out. The reasonable charge set of cut hole is determined to be 0. 54 kg/m. Then determine the design parameters of III class wall rock smooth blasting in Maotian boundary tunnel. By defining the load sub-step at different initial time to achieve millisecond blasting effect, verify the rationality of smooth blasting parameters. Finally. The basic law of dynamic response of metamorphic sandstone in Maotian boundary tunnel is analyzed by using ANSYS/LS-DYNA software. The numerical simulation results show that the direction of particle vibration is consistent with the direction of stress wave propagation. The main frequency is higher than the vibration frequency in other directions, and the sensitivity of the main frequency varies with the displacement is low. The peak vibration velocity of the particle, the peak displacement of the particle and the peak value of the first principal stress of the arch all show the characteristics of decreasing with the increase of the distance between the detonation sources. The first principal stress from the arch top to the bottom of the side wall is transformed from the main tensile stress to the main compressive stress; The reasonable blasting scale of III grade surrounding rock of Maotian boundary tunnel is 3 ~ 4 m; The dynamic response of rock mass within 1 m of tunnel face is the most sensitive.
【學(xué)位授予單位】：華中科技大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類(lèi)號(hào)】：U451.2

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相關(guān)碩士學(xué)位論文 前1條

1 王光壯;茅田界隧道變質(zhì)砂巖動(dòng)力響應(yīng)特性研究[D];華中科技大學(xué);2015年

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本文編號(hào)：1379994