本文選題：淺埋松散圍巖 + 破壞模式　； 參考：《西安理工大學》2017年碩士論文

【摘要】：隨著公路隧道工程的增多,淺埋松散圍巖隧道的坍塌事故越來越多,而常規(guī)有限元方法(未考慮松散巖體結構面及塌落體的作用)和結構荷載法在計算圍巖壓力和支護設計中均存在一定的弊端。本文基于Peck公式理論和有限元方法提出了淺埋松散圍巖破裂面特征的計算模型,對比驗證了本文方法的合理性,并對其影響因素進行了敏感性數(shù)值分析,提出了一種考慮支護時機的圍巖壓力計算方法。最后基于本文提出的隧道圍巖破裂面模型,建議了一種改進型擬塌落拱離散化有限元方法,并對其適用性進行了數(shù)值分析和工程實際驗證。通過本文研究,得到的主要結論如下:1.經(jīng)過隧道塌方案例調研分析,大多數(shù)圍巖破壞的破壞模式與規(guī)范方法和傳統(tǒng)的破壞模式中假定的破壞位置及破裂角存在較大差異。鑒于此,本文提出了基于peck曲線確定滑裂面的計算模型和方法,并與文獻中的模型實驗、數(shù)值實驗和工程實例進行對比分析,驗證了本方法的合理性。2.基于本文提出的破裂面計算模型,研究了破裂角β及地表破裂點i0與隧道的覆跨比w,彈性模量E,泊松比μ,內(nèi)摩擦角φ,粘聚力c及圍巖類別(Ⅳ、Ⅴ、Ⅵ)的關系,并對其進行了敏感性分析。3.本文根據(jù)隧道的破壞模式提出了可以考慮支護時機的圍巖壓力計算方法,分析了支護時機對圍巖壓力的影響,并與經(jīng)典圍巖壓力計算方法對比,揭示了規(guī)范方法在圍巖壓力計算和支護結構設計中存在的問題。4.基于本文的破裂面模型,提出了改進的擬塌落拱離散化有限元方法,分析了支護時機,滑裂面位置、結構面間距、結構面強度、結構面夾角、巖塊參數(shù)等對圍巖變形和支護受力的影響,并通過工程案例驗證了本方法的適用性。
[Abstract]:With the increase of highway tunnel engineering, there are more and more accidents of shallow buried loose surrounding rock tunnel collapse. But the conventional finite element method (not considering the action of loose rock mass structure plane and collapse body) and the structural load method have some disadvantages in the calculation of surrounding rock pressure and support design. Based on Peck formula theory and finite element method, a calculation model of fracture surface characteristics of shallow loose surrounding rock is proposed in this paper. The rationality of this method is verified by comparison, and the sensitivity numerical analysis of its influencing factors is made. A calculation method of surrounding rock pressure considering the time of supporting is put forward. Finally, based on the fracture surface model of tunnel surrounding rock proposed in this paper, a modified finite element method for quasi-collapse arch discretization is proposed, and its applicability is analyzed numerically and verified in engineering practice. In this paper, the main conclusions are as follows: 1. Through investigation and analysis of tunnel collapse cases, the failure modes of most of the surrounding rocks are different from those of the standard method and the traditional failure modes, such as the assumed failure location and the fracture angle. In view of this, this paper presents a calculation model and method for determining the slip surface based on the peck curve, and compares it with the model experiments, numerical experiments and engineering examples in the literature, and verifies the rationality of the method. Based on the fracture surface calculation model proposed in this paper, the relationship between the fracture angle 尾 and the surface rupture point i0 and the overburden span ratio (w), elastic modulus (E), Poisson's ratio 渭, the angle of internal friction (蠁), the cohesive force (c) and the types of surrounding rock (鈪，

本文編號：2043266