高水压隧道衬砌混凝土损伤特性研究

发布时间：2018-04-11 06:28

本文选题：高水压 + 衬砌　；参考：《重庆交通大学》2015年硕士论文

【摘要】：很多隧道在投入运营以后会出现不同程度的损伤,如混凝土劣化、钢筋锈蚀、渗漏水严重等现象,影响隧道的正常使用。高水压地段隧道衬砌要承受围岩压力以及外水压力,由于混凝土的渗透性,地下水会在混凝土内的裂纹和孔隙内渗流给混凝土带来内部孔隙水压力。此外,隧道内部环境复杂且地下水中侵蚀性离子较多,会对衬砌混凝土造成腐蚀。隧道衬砌混凝土的碳化和钢筋锈蚀以及裂损可以降低混凝土的强度,增大混凝土的孔隙度,在水压作用下促进水体的渗透,与此同时混凝土的渗流场与应力场相互作用,影响其损伤的发展。本文分析了隧道的复杂环境对衬砌混凝土耐久性损伤的影响;运用断裂力学应力强度因子分析衬砌在拉压应力作用下裂纹深度对其损伤发展造成的影响;研究了水压渗透作用下衬砌混凝土内部渗流场与应力场之间的耦合关系,并利用有限元软件ABAQUS分析渗流—应力耦合作用下对混凝土损伤的影响。本文的主要工作及成果如下:①公路隧道通车量的较多,导致隧道内部堆积的酸性气体增多,加快了衬砌混凝土的碳化损伤,降低混凝土的工作性能。富水区隧道地下水中含有很多侵蚀性离子对混凝土以及钢筋混凝土中的钢筋进行侵蚀,使混凝土与钢筋的有效承载面积减少,损伤量增加。据此建立了混凝土碳化损伤模型以及钢筋锈蚀损伤模型。②运用断裂力学原理,根据应力强度因子针对裂纹深度对衬砌结构损伤影响进行分析。应力强度因子是判断衬砌结构破坏失稳的重要因子,其值与衬砌在拉伸、弯矩作用下的轴力和弯矩成正比。当在裂纹发展初期,其深度对混凝土损伤的影响是很缓慢的,但是到了一定程度后,应力强度因子发生突变,这时裂纹深度很小的扩展都会加剧衬砌混凝土损伤,直至发生贯穿裂缝影响衬砌的承载能力。③混凝土自身带有微裂纹、微孔隙等初始损伤,在外界环境和周围压力的作用下,初始损伤逐渐扩展,在高水压的作用下提高了其渗透性能。隧道衬砌混凝土内渗流场与应力场相互作用,相互演化,影响着损伤的发展。本文建立了衬砌混凝土在高水压下渗流场与应力场的耦合关系,并建立渗流系数与应力、损伤之间的关系。通过ABAQUS有限元软件对高水压下隧道衬砌混凝土进行模拟,得到衬砌混凝土在渗流与应力耦合作用下损伤出现在拱腰部位,并且隧洞内侧衬砌损伤最先发展,损伤与等效塑性应变以及渗流系数具有一定的相关性。本文的研究可以作为在隧道某个位置和时间设置各项装置对损伤进行检测,及时采取有效措施防止衬砌的损伤提供依据。
[Abstract]:Many tunnels will be damaged in varying degrees after they are put into operation, such as deterioration of concrete, corrosion of steel bars, serious leakage of water and so on, which will affect the normal use of tunnels.The tunnel lining in high water pressure area must bear the surrounding rock pressure and the external water pressure. Because of the permeability of the concrete, the underground water will bring the internal pore water pressure to the concrete because of the crack in the concrete and the seepage in the pore.In addition, the inner environment of tunnel is complex and there are more erosive ions in groundwater, which will cause corrosion to lining concrete.The carbonization of tunnel lining concrete, the corrosion of steel bar and the cracking can reduce the strength of concrete, increase the porosity of concrete, promote the permeation of water body under the action of water pressure, at the same time, the seepage field and stress field of concrete interact with each other.Affect the development of its damage.In this paper, the influence of the complex environment of tunnel on the durability damage of lining concrete is analyzed, and the influence of crack depth on the damage development of lining under tension and compression stress is analyzed by using the stress intensity factor of fracture mechanics.The coupling relationship between seepage field and stress field in lining concrete under hydraulic seepage is studied, and the effect of seepage and stress coupling on concrete damage is analyzed by finite element software ABAQUS.The main work and results of this paper are as follows: the traffic volume of the 1% 1 highway tunnel increases the accumulation of acid gas in the tunnel, accelerates the carbonation damage of the lining concrete, and reduces the working performance of the concrete.There are a lot of erosive ions in the groundwater of the water-rich tunnel to erode the concrete and the reinforcement in the reinforced concrete, so that the effective bearing area of concrete and steel bar is reduced, and the damage amount is increased.Based on this, the concrete carbonization damage model and steel bar corrosion damage model .2 are established. According to the stress intensity factor, the influence of crack depth on the damage of lining structure is analyzed according to the principle of fracture mechanics.The stress intensity factor is an important factor in judging the failure and instability of lining structure, and its value is proportional to the axial force and moment of lining under the action of tension and bending moment.In the early stage of crack development, the effect of crack depth on concrete damage is very slow, but after a certain extent, the stress intensity factor changes, and the crack depth will increase the damage of lining concrete if the crack depth is very small.Until the load-carrying capacity of concrete affected by the cracks through the lining itself has microcracks, micro-pores and other initial damage, under the external environment and ambient pressure, the initial damage gradually spread,The permeability was improved under the action of high water pressure.The interaction and evolution of seepage field and stress field in tunnel lining concrete affect the development of damage.In this paper, the coupling relationship between seepage field and stress field of lining concrete under high water pressure is established, and the relationship between seepage coefficient and stress and damage is established.Through the simulation of tunnel lining concrete under high water pressure by ABAQUS finite element software, it is concluded that the damage of lining concrete under the coupling of seepage and stress appears at the arch waist, and the lining damage on the inside of the tunnel develops first.There is a certain correlation between damage and equivalent plastic strain and seepage coefficient.The research in this paper can be used as a basis for the installation of various devices at a certain location and time of the tunnel to detect the damage and take effective measures to prevent the damage of the lining in time.
【学位授予单位】：重庆交通大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U451.4;U455.91

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