本文選題：襯砌背后空洞 + 圍巖壓力分布　； 參考：《北京交通大學》2014年碩士論文

【摘要】：摘要：隨著隧道運營數(shù)量的不斷增加,運營時間的不斷增長,已有大量的隧道出現(xiàn)了不同程度的病害現(xiàn)象,如襯砌變形、裂損、道床損壞、結構滲漏水等,嚴重威脅著隧道內(nèi)的行車安全。造成隧道出現(xiàn)病害的原因有很多,其中,襯砌背后存在空洞是主要原因之一。襯砌背后存在空洞改變了襯砌與圍巖的相互作用關系,惡化了襯砌的受力狀態(tài),造成了襯砌病害的產(chǎn)生。準確的確定襯砌的受力狀態(tài)對隧道病害的預防及治理具有重要的意義。 為明確空洞存在下襯砌的受力狀態(tài),本文采用數(shù)值模擬的方法對襯砌背后存在空洞時圍巖壓力分布規(guī)律、諸如隧道埋深、圍巖級別等因素對圍巖壓力分布的影響規(guī)律及空洞存在時襯砌安全系數(shù)計算的模型等進行了研究,得出以下主要研究結論： (1)襯砌背后存在空洞,改變了荷載的傳遞路徑,改變了圍巖壓力的分布規(guī)律,在空洞兩側形成了圍巖壓力增大區(qū)和圍巖壓力減小區(qū)。 (2)定義了壓應力平均增大系數(shù)及壓應力增大范圍兩個參數(shù)來表征圍巖壓力增大區(qū)的特征,得出壓應力平均增大系數(shù)隨圍巖級別、隧道埋深及襯砌厚度的增加,而呈逐漸減小的趨勢,隨開挖范圍及釋放系數(shù)的增加而呈逐漸增大的趨勢；壓應力增大范圍隨空洞范圍、圍巖級別、隧道埋深及襯砌厚度的增大而呈逐漸增大的趨勢,隨釋放系數(shù)的增大呈逐漸減小的趨勢。 (3)對于空洞組合而言,當空洞范圍較小,空洞相距較遠時,空洞群之間疊加效應較小,圍巖壓力分布及襯砌變形規(guī)律與單空洞相同；當空洞范圍較大或相距較近時,兩空洞間存在疊加區(qū)域,會改變疊加區(qū)域內(nèi)的圍巖壓力分布,降低疊加區(qū)域內(nèi)襯砌的安全系數(shù)。 (4)基于以上所得規(guī)律,提出了考慮空洞兩側圍巖壓力增大區(qū)影響的荷載-結構模型中的荷載加載模式,并通過算例對比分析了考慮與不考慮圍巖壓力增大區(qū)兩種情況下襯砌的安全性,計算結果表明考慮圍巖壓力增大區(qū)的影響時,襯砌安全系數(shù)普遍降低,最危險位置由空洞中心向空洞兩側轉(zhuǎn)移。
[Abstract]:Absrtact: with the increase of tunnel operation quantity and operation time, a large number of tunnel diseases have appeared in different degrees, such as lining deformation, crack, road bed damage, structural leakage and so on. It is a serious threat to the traffic safety in the tunnel. There are many causes of tunnel disease, among which, the hole behind the lining is one of the main reasons. The existence of cavity behind the lining changes the interaction between the lining and the surrounding rock, worsens the stress state of the lining, and causes the lining disease. It is of great significance to accurately determine the stress state of lining for the prevention and treatment of tunnel diseases. In order to make clear the stress state of lining under the existence of cavities, this paper uses numerical simulation method to analyze the pressure distribution law of surrounding rock when the cavity exists behind the lining, such as the depth of tunnel burying. The influence of surrounding rock grade and other factors on the pressure distribution of surrounding rock and the model for calculating the safety factor of lining are studied. The main conclusions are as follows: (1) there are voids behind the lining. The load transfer path is changed, and the distribution of surrounding rock pressure is changed. Surrounding rock pressure increasing zone and surrounding rock pressure decreasing zone are formed on both sides of the cavity. (2) two parameters are defined to characterize the characteristics of the surrounding rock pressure increasing area, namely, the average increase coefficient of the compressive stress and the range of the compressive stress increase. The results show that the average increase coefficient of compressive stress increases gradually with the increase of surrounding rock level, the depth of tunnel and the thickness of lining, and increases with the increase of excavation scope and release coefficient, and the range of compressive stress increases with the cavity range. The surrounding rock level, the depth of tunnel and the thickness of lining increase gradually, and decrease with the increase of release coefficient. (3) for cavity combination, when the cavity range is small and the cavity is far away, The distribution of surrounding rock pressure and the deformation of lining are the same as that of single cavities, and when the voids are large or close to each other, there is a superposition area between the two voids, which will change the pressure distribution of surrounding rock in the superimposed area. (4) based on the above law, the load-loading mode in the load-structure model considering the influence of surrounding rock pressure on both sides of the cavity is proposed. The safety of lining is analyzed with and without considering the increase of surrounding rock pressure. The calculation results show that the safety factor of lining decreases when considering the influence of surrounding rock pressure increasing zone. The most dangerous position shifts from the center of the cavity to the side of the cavity.
【學位授予單位】：北京交通大學
【學位級別】：碩士
【學位授予年份】：2014
【分類號】：U451.2

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本文編號：2071939