【作者】 胡辉；

【导师】 仇文革；

【作者基本信息】 西南交通大学 ， 桥梁与隧道工程， 2013， 博士

【摘要】 本文以国家自然科学基金重点项目《长大隧道地震响应机理与抗震》为依托,综合运用调查研究、理论推导、数值模拟、模型试验等方法,对隧道震害突出问题进行了归纳总结,并针对隧道穿越活动断层进行了重点研究,建立了以模型试验方法研究隧道穿越断层破坏形态及抗减震措施的可靠手段,给出了不同减震措施的试验效果,并提出了隧道运用新型吸能减震结构的建议和办法。主要研究结论和成果如下：(1)在现场调查及资料调研等基础上,将长大隧道震害严重区段分为三大类：洞口段、洞身软弱破碎段及穿越活动断层段。(2)对隧道洞身段远场地震波作用下动力响应特征进行了数值模拟分析,结果表明,洞身穿越软弱破碎带远场地震波动力响应明显大于硬岩段,隧道容易发生震害破坏。在考虑波的绕流特性及松动圈理论基础上,推导了硬岩隧道洞身深埋段的衬砌结构内力计算公式。(3)提出了一种合理可靠的隧道穿越活动断层模型试验方法,通过与实际震害调查进行比较,认为试验得出的结果是可靠的,试验装置以及试验设计能够满足模拟隧道穿越活动断层力学行为特征的基本要求,隧道破坏特征明显,与实际隧道震害基本吻合。(4)模型试验通过对隧道衬砌纵向设置不同间距减震缝,分析了设缝对隧道穿越活动断层的减震效果,试验表明：与不设缝相比,设置减震缝能够有效的控制隧道受断层错动影响的纵向破坏距离以及受断层错动作用产生的内力增量；减小设缝间距能够进一步控制隧道受断层错动影响的纵向破坏距离。但断层处衬砌由于纵向长度很小,单环承受荷载的能力下降,中心处衬砌环发生了非常严重的破坏,抗减震问题更为突出：通过对比试验,认为初期支护应设置减震缝。在初支不设减震缝情况下,初支自身在断层带附近严重破裂剥离失效,同时加重了二次衬砌的破坏。(5)采用扩大断面并设置纵向减震缝能有效保证断层错动后隧道有效净空面积,扩大断面的设计应与工程所在地点的预计最终静态滑动量相关,通过与减震缝组合的方式达到保证净空的效果。断层与隧道轴向夹角越大,相同错动位移下隧道净空损失越大,在保证震后净空设计值需要的情况下,扩大断面尺寸越大；断层与隧道轴向夹角越小,相同错动位移下断层对隧道的影响范围越大,所需要的设缝范围也越大。工程抗震设计时应根据断层的走向及错动量合理安排扩大断面的尺寸以及减震缝设缝距离,达到保证减震效果与控制工程造价的双重目标。(6)隧道穿越活动断层时采用减震缝设计是一种有效的减震方法,但由于混凝土衬砌本身的材料特性不足,不能抵抗断层错动瞬时产生的剧烈作用和荷载,不具备缓冲和吸能的能力,迫切的需要改进材料特性以解决设缝后断层带衬砌自身稳定能力。(7)提出了一种新型柔性吸能减震结构,即橡胶衬砌。与传统衬砌相比,在相同的错动作用下,橡胶衬砌自身能发生较大的变形,但无任何裂缝及破坏情况,结构处于良好的弹性变形状态；橡胶衬砌能够缓冲断层错动时产生的动力响应作用；橡胶衬砌设置减震缝能大大减小断层范围以外衬砌的内力增量；橡胶衬砌设置较小间距减震缝能减小断层错动对衬砌的影响范围：随着减震缝间距的减小,断层处衬砌错动趋于均匀,错台变小；从断层影响范围来看,减震缝间距为20cm、10cm、5cm和2.5cm时衬砌错动的范围分别为60cm、40cm、30cm、25cm,基本在断层附近。(8)通过断层错动数值模拟,认为地震的能量级别与破裂面的强度有关,破裂面强度越高,震前积聚的能量越高,地震时越剧烈,隧道只能通过纵向设缝的办法适应断层错动,环向采取柔性吸能的衬砌材料减震。影响隧道结构环向动力附加荷载因素为震级和刚度比,地震的震级越高,活动断层的错动越剧烈,隧道震害越严重。刚度比越大,衬砌的内力响应越剧烈,刚度比小于1时,隧道结构比围岩更柔性,与围岩一起变形,动力响应很小。(9)橡胶衬砌的弹性较好,相同荷载下其持续变形的能力远大于普通衬砌,隧道在较大荷载及变形的情况下能够保持不垮塌,当荷载消失后,橡胶衬砌仍能够恢复受力前的状态,不会发生永久破坏。从能量的角度来讲,橡胶衬砌的吸能水平远大于普通衬砌(s2>>s1),是一种吸能的新型减震结构。(10)橡胶衬砌的使用应根据断层可能发生的错动量及自身的刚度决定,同时配合扩大断面的设置,按照最终错动量与自身变形量之和设计预留净空,按最大位移量确定橡胶衬砌的材料性能要求。更多还原

【Abstract】 Based on major project (No.51038009) of National Natural Science Foundation of China, by using methods of field investigation, theoretical analysis, numerical analysis and model test, the prominent problem of tunnel damage by earthquake is summarized. Focused research is aimed at tunnel passing through active fault, reliable methods as model test to simulate tunnel damage when passing through active fault and study aseismic measures are established, test result of different aseismic measures is give. Finally, a new type energy absorption lining structure for tunnel is proposed and studied. The main conclusions and outcomes are as following:(1) Based on field investigation and document research, serious seismic damage zone of long and large depth tunnel are three categories:portal section, week and broken zone of tunnel body and tunnel passing through active fault.(2) Numerical analysis of tunnel body dynamic response by seismic load is made, indicating dynamic response of tunnel passing through week and broken zone is obviously larger than that in hard rock zone, tunnels are more likely to earthquake damage.(3) A reliable method as model test to simulate tunnel damage when passing through active fault and study aseismic measures is established, test result is reliable, testing apparatus and design fulfil basic requirements of simulating mechanical behavior when tunnel passing through active faults, tunnel damage characteristics are obviously coincided with actual damage.(4) By measures of setting aseismic joint, damping effect by aseismic joint for tunnel passing through active fault is analyzed. The test shows setting aseismic joint may control longitudinal damage distance influenced by fault movement and control internal force increment. By reducing aseismic joint separation distance, different damping effect of different joint separation distance are studied, the test shows that reducing aseismic joint separation distance may further control longitudinal damage distance influenced by fault movement, but monocyclic ring in the centre may more likely to damage, due to short longitudinal length, the seismic problem may be more prominent. By contrast test, primary support is expected to set aseismic joint, rather than serious fracture and peeling phenomenon, as well as aggravating secondary lining damage. (5) Adopting expanded section and setting aseismic joint are able to guarantee tunnel effective clearance after fault movement, the design of expanded section should be related to estimated final static slippage and combined use with setting aseismic joint to guarantee tunnel effective clearance. The bigger intersection angle between fault and tunnel axial, the bigger loss of tunnel clearance. To guarantee designed tunnel clearance after earthquake, the expanded section should be bigger. The smaller intersection angle between fault and tunnel axial, the bigger range of influence by fault in the same fault displacement, the range of aseismic joint should be greater. The expanded section dimensions and aseismic joint distance should be reasonable arrangement due to the fault direction and fault displacement to guarantee damping effect and control engineering cost of projects.(6) Setting aseismic joint design is a effective damping method for tunnel passing through active fault, but due to material characteristics defect of concrete lining, the lining cannot bear severe impact and load during fault movement, and possess not the ability of buffer and absorbing energy. Material characteristics is in urgent need to be improved to solve lining homeostasis.(7) Compared with tradition lining, rubber lining can bear larger deformation in the same fault movement, growing no crack or damage, the lining structure is in favourable elastic deformation state. The rubber lining has the buffer of dynamic response during fault movement. Cooperated with setting aseismic joint, internal force increment of lining near fault zone may greatly reduced. Cooperated with short distance aseismic joint, influence region is more reduced, faulting of slab ends is less. When aseismic joint distance are20cm,10cm,5cm and2.5cm, lining slide60cm,40cm,30cm,25cm, the zone is more tend to fault zone.(8) Dynamic additional load on tunnel structure in section are influenced by earthquake magnitude and stiffness ratio, based on simulation of fault movement, the higher the earthquake magnitude and the severer the fault movement, the more serious the tunnel earthquake damage. The bigger the stiffness ratio, the severer the internal force response of lining. When the stiffness ratio is less than1, the tunnel is more flexible than surrounding rock, dynamic response is less.(9) elasticity of rubber lining is good and has larger deformation in same load, compared with common lining, continuous deformation capability is far larger than common lining. Tunnel can keep no collapse in large load and deformation, when the load is gone, the rubber lining is even able to recover and will have no permanent damage. From the energy point of view, energy absorption capability of rubber lining is far larger than common lining, being a new type endergonic and flexible aseismic structure.(10) The use of rubber lining should in accordance with possible fault movement and lining stiffness, and cooperate with setting expanded section. Obligate clearance design is sum of final fault movement and self-deformation, material performance requirement of rubber lining is according to maximum displacement during fault movement.更多还原