發(fā)布時間：2018-05-08 21:04

  本文選題：隧洞圍巖 + 長期強度　； 參考：《大連理工大學》2015年碩士論文

【摘要】：基于對巖石長期強度的認識,從巖石的強度、彈模等物理力學性質受環(huán)境因素影響隨時間劣化以及巖石內(nèi)部細觀損傷積累的角度出發(fā),通過引入巖體細觀表征單元體的強度退化方程,應用RFPA數(shù)值模擬方法,研究隧洞圍巖的損傷演化與時效破壞機制。首先,模擬了巖石的單軸壓縮蠕變試驗和隧洞的時效變形破壞過程,并分別與相應的物理試驗結果進行了對比,數(shù)值模擬結果很好地反映了軟弱巖石典型蠕變的三階段：初始、穩(wěn)定和加速階段；隧洞數(shù)值模擬試驗得到了拱頂、拱底以及兩側幫的時效變形特征曲線,與實際物模試驗結果表現(xiàn)出了較好的一致性。作為參數(shù)分析,進一步模擬分析了側壓系數(shù)對隧洞時效損傷破壞特性的影響,模擬結果顯示,隨著側壓系數(shù)的增大,隧洞左右邊墻間的收斂位移逐漸增大,而隧洞拱頂拱底間的閉合位移隨側壓系數(shù)的增大逐漸減小,并對隧洞圍巖的局部的細觀損傷演化過程及宏觀時效破壞模式做出了清晰的解釋。其次,研究了軟弱夾層的分布對隧洞圍巖損傷演化和時效破壞的影響,發(fā)現(xiàn)隧洞周圍應力場和位移場分布的對稱性在軟弱夾層的影響下發(fā)生明顯的改變,出現(xiàn)向軟弱夾層附近“遷移”的現(xiàn)象,使得洞室與軟弱夾層之間形成高應力集中區(qū),進而造成臨近軟弱夾層一側巖體的位移和破壞程度明顯增大；由于軟弱夾層分布位置的不同,隧洞圍巖的時效損傷破壞模式也出現(xiàn)明顯的差異。作為參數(shù)分析,進一步模擬分析了軟弱夾層厚度對隧洞圍巖時效損傷破壞特性的影響,模擬結果顯示,隨著軟弱夾層厚度的增加,隧洞的拱頂、兩側邊墻位移不斷地增大,隧洞的破壞程度也越來越嚴重,夾層厚度對隧洞時效損傷破壞的影響顯著增大。進而,模擬分析了節(jié)理分布傾角對隧洞圍巖的損傷演化和時效破壞機制的影響,發(fā)現(xiàn)在節(jié)理的影響下,隧洞開挖后,圍巖的應力分布規(guī)律發(fā)生明顯的改變；節(jié)理為水平節(jié)理時,隧洞以兩側邊墻片幫破壞為主；隨著節(jié)理面傾角的變化,隧洞圍巖的的時效損傷破壞模式也發(fā)生了明顯的變化,隧洞損傷破壞區(qū)隨節(jié)理傾角的增大相應旋轉；當節(jié)理方向豎直時,隧洞破壞主要集中于拱頂和拱底部位,出現(xiàn)了嚴重的冒頂和底鼓現(xiàn)象。同時,在節(jié)理面的影響作用下,隧洞周圍圍巖的位移發(fā)生明顯的變化,并且隨著節(jié)理傾角的增大,隧洞位移呈現(xiàn)出先增后減的大致趨勢。最后,以伊朗Taloun公路隧道的服務隧洞為工程背景,對其進行了損傷演化和時效破壞特性的實例分析。
[Abstract]:Based on the understanding of the long-term strength of rock, the physical and mechanical properties such as rock strength and elastic modulus are affected by environmental factors and the accumulation of meso damage in rock. By introducing the strength degradation equation of the rock mass characterization unit, the damage evolution of the tunnel surrounding rock is studied by the RFPA numerical simulation method. First, the uniaxial compression creep test of rock and the aging deformation and failure process of the tunnel are simulated, and the results are compared with the corresponding physical test results respectively. The numerical simulation results reflect the three stages of the typical creep of the soft rock: initial, stable and accelerating stages; the numerical simulation test of the tunnel has been obtained. The aging deformation characteristic curve of the vault, arch bottom and both sides shows good consistency with the actual model test results. As a parameter analysis, the influence of the side pressure coefficient on the damage characteristics of the tunnel aging damage is further simulated and analyzed. The simulation results show that the convergence displacement between the left and right side walls of the tunnel is increased with the increase of the lateral pressure coefficient. Gradually, the closure displacement between the arch top and the arch of the tunnel gradually decreases with the increase of the lateral pressure coefficient, and makes a clear explanation for the local mesoscopic damage evolution process and the macroscopic aging failure mode of the tunnel surrounding rock. Secondly, the influence of the distribution of the weak interlayer on the damage evolution and the aging damage of the tunnel surrounding rock is studied, and the tunnel surrounding the tunnel is found to be around the tunnel. The symmetry of the distribution of stress and displacement fields is obviously changed under the influence of weak intercalation, and the phenomenon of "migration" to the weak intercalation causes the formation of high stress concentration zone between the cavern and the weak intercalation, and the displacement and damage degree of the rock mass near the weak intercalation is obviously increased, and the weak interlayer is divided into the weak intercalation. As a parameter analysis, the influence of the thickness of the weak interlayer on the damage characteristics of tunnel surrounding rock is further simulated and analyzed. The simulation results show that the displacement of the vault and side wall of the tunnel increases continuously with the increase of the thickness of the weak interlayer. The damage degree of the cave is becoming more and more serious, and the influence of the thickness of the interlayer on the damage and damage of the tunnel is significantly increased. Then, the influence of the joint dip angle on the damage evolution and the aging failure mechanism of the tunnel surrounding rock is simulated and analyzed. It is found that the stress distribution law of the surrounding rock changes obviously after the tunnel excavation. In the case of horizontal joints, the tunnel is mainly damaged by the side wall of the tunnel. With the change of the angle of the joint, the damage failure mode of the tunnel surrounding rock has also changed obviously. The damage zone of the tunnel rotates with the increase of the joint dip. When the joint direction is vertical, the tunnel failure is mainly concentrated on the vault and the bottom of the arch. There is a serious roof and bottom drum phenomenon. At the same time, under the influence of the joint surface, the displacement of the surrounding rock around the tunnel is obviously changed, and with the increase of the joint inclination, the tunnel displacement presents a general tendency to increase first and then decrease. Finally, the damage performance of the service tunnel of the Iran Taloun highway tunnel is taken as the engineering background. Case analysis of chemical and aging failure characteristics.

【學位授予單位】：大連理工大學
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：TU45

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本文編號：1863047