【作者】 黄胜；

【导师】 陈卫忠；

【作者基本信息】 中国科学院研究生院（武汉岩土力学研究所） ， 岩土工程， 2010， 博士

【摘要】 我国西部地区具有全球独特、最复杂的地质构造,第四纪以来,新构造运动、地震活动频繁,活动断裂发育,在青藏高原如此复杂的地质条件下,西部地区基础建设过程中不可避免的会遇到在活断层附近和高烈度地震区修建隧道工程的问题。因此,研究高烈度地震区隧道的破坏机制,并提出有针对性的抗震措施,对拟建隧道选址、设计、施工具有重大的现实意义。本文的工作从研究高烈度地震区隧道震害机制出发,首先进行了岩石和研制的新型隔震材料泡沫混凝土的动力学特性研究,然后开展了地震波的合理选取和针对地下工程的合理地震动输入机制研究,进一步,以上述两部分的研究成果为基础,论文开展了高烈度地震下隧道动力响应特性和稳定性评价研究,抗震材料及抗震方法研究,同时还进行了隧道地震作用下动力响应的远程自动监测。论文的主要研究成果如下：1、基于无限元人工边界的地下工程合理的地震动输入方法地下工程抗震分析中一个关键的环节是地震动的合理输入,但是目前不少人沿用地面建筑物的地震动输入方式,这对地下工程是不合适的。为此,本文提出一种新的基于无限元人工边界的合理的地震动输入方法,本方法考虑到了地层的辐射阻尼和地震波在地层中的反射和散射,采用波场分解的方法给出了地震波从底面垂直入射时底边界和侧边界面各自不同的等效地震荷载的计算公式,并基于abaqus进行二次开发编制了相关的程序,同时进行了算例考证。2、一种新型抗震材料泡沫混凝土的研制及其动力特性研究研制了一种新型隔震材料泡沫混凝土,采用正交试验进行了配合比方案比选,遴选出轻质、低强度和较好延性的方案,具有较好的隔震和缓冲性能,然后对优选方案开展了的动三轴试验,分析材料在地震应变率范围内的变形和强度特征,试验结果表明：泡沫混凝土抗压强度均随应变速率的增加而增加；试验中该材料无剪胀现象,这是由于泡沫混凝土多孔隙所致；泡沫混凝土在动态压缩荷载作用下轴向变形明显,但破坏后仍保持完整性,这表明该材料具有较好的延性,地震中可以耗散相当多的地震能量。3、隧道地震反应特性研究研究了隧道动态响应特性,结果表明：地震强度和持时增加,隧道位移增大；低频地震波导致的隧道位移明显高于高频地震,因此低频的地震更易造成隧道的破坏；对剪切波,水平入射时位移响应幅值最小,垂直入射时位移响应幅值最大；随着埋深的增加,隧道位移响应有明显减小的趋势,但是这种趋势只是针对一般地质情况,在围岩质量、地应力和断层的交叉影响下,埋深较大时也会出现震害。4、近场区活断层对隧道安全性的影响研究隧道近场区发震断层引发的地震不同于一般远场地震,具有速度脉冲效应、较大的峰值和较长的周期。由于缺乏实际地震监测记录,本文首先根据近场区地震动参数,采用考虑高频分量叠加的等效脉冲模型,人工合成了近断层脉冲地震动记录,然后采用运动学震源模型,将上述合成波用于模拟隧道进口处走滑断层错动激震,以此来评价隧道的地震安全性。另外,本文还开展了地震引发的次级断层错动对隧道安全性影响的初步研究,同时分析了隧道洞口边坡震害对隧道稳定性的影响。5、高烈度地震下隧道工程抗震方法研究首先归纳出了隧道抗震设计的两个总体思路,即：改变衬砌一定范围内围岩的性能和改变结构本身的性能,接着沿循这两个思路总结了目前隧道采用的各类抗减震措施,然后据此开展了隧道抗震设计方法的一系列研究,包括隧道断面型式优化研究、减震层减震效果研究、加固围岩减震效果研究以及隧道抗错断设计研究。其中减震层研究方面,通过数值试验验证了泡沫混凝土的隔震效果,泡沫混凝土采用crushable-foam率相关本构模型,结果表明泡沫混凝土作为衬砌隔震层具有较好的隔震效果,并针对工程具体情况给出了合理经济的隔震层厚度。另外本文专门比较了采用隔震层抗震和传统的提高刚度抗震两类思路的优劣,最后综合以上的工作,针对隧道工程的抗震设计提出了一些适用性的建议。6、嘎隆拉隧道抗震和现场地震监测研究综合运用上述研究成果,开展嘎隆拉隧道动力响应分析研究,评估近场断层错动激震和高烈度远场地震对包含F7非发震弱断层的进洞口区域的影响,并提出了适合嘎隆拉隧道的抗震措施。同时进行了隧道地震作用下动力响应的远程无线监测,通过在隧道进洞口处埋设加速度仪,获得三个方向的加速度动力时程记录,可以为研究隧道工程在地震动时的真实动力响应特性提供第一手现场资料。更多还原

【Abstract】 China has the most complex geological structure in the west region, which is unique in the world. Since Quaternary Period, tectonic movement and earthquake activity are frequent, active faults develop. In such complicated geological conditions of tibetan plateau, the tunnel may have to be constructed beside active fault and in high seismic intensity area.Therefore, research on tunnel failure mechanism in high seismic intensity area and the proposed aseismic measures accordingly will greatly benefit the project location selecting, design and construction of tunnel engineering.Research work of this paper starts from study of tunnel seismic damage mechanism in high seismic intensity area. Firstly, dynamic mechanical properties of rock and a new vibration absorbing material-foamed concrete are studied in this paper,then, reasonable selection method for seismic wave and a new earthqukae input method in aseismic analysis for underground engineering are both considered, futhermore,on the basis of the above two work,characteristic of tunnel seismic response in high seismic intensity area and stability evaluation are carried out deeply, and the corresponding aseismic methods are summarizd and analyzed,meanwhile, remote earthquake monitoring of the tunnel is also carried out. The main achievements are conducted as follows:1. Study on method of earthqukae input in aseismic analysis for underground engineering based on infinite element dynamic artificial boundaryA crucial link in underground engineering aseismic analysis is appropriate earthquake input method, but now a considerable number of people apply the earthquake input method used in surface buildings, which is not appropriate for underground buildings. Therefore, a new earthquake input method based on infinite element dynamic artificial boundary is proposed by this paper, in this new method, radiation damping of the strata and reflection, scattering of the seismic wave in the strata are both considered, and equivalent earthquake load formulae in different boundary surfaces for seismic waves vertically incident from the bottom of computational domain are deduced, using the wave field separation method. Meanwhile, a numerical example is conducted to verify the validity and accuracy of the method.2. Development of a new vibration absorbing material-foamed concrete and research on its dynamic mechanical propertyA new vibration absorbing material-foamed concrete has been developed, which has light weight, low strength and good ductility, and the formula of which is selected through orthogonal test, then, dynamic triaxial test is carried out on foamed concrete,analysing the deformation and strength characteristics within a seismic strain rate range,the results show that compressive strength of this material increse with increasing of strain rate;the material has no dilatancy phenomenon because of its porosity;the axial deformation of foamed concrete is obvious under dynamic compressive loading, however, it still keeps integrity after failure,which shows that foamed concrete has good ductility and can dissipate considerable seismic energy.3. Research on seismic response characteristics of tunnelSeismic response characteristics of the tunnel is studied in this paper, the results show that the displacements of cavern increase with the increasing earthquake amplitude and duration time; the cavern displacement induced by low-frequency earthquake is larger than high-frequency earthquake, which means that the cavern failure is more easily induced by low-frequency earthquake; for shear wave, the displacement is the smallest when wave incidence is horizontal,and the biggest when wave incidence is vertical; cavern displacement will decrease with the increasing buried depth, however, this trend is just fit for general geological condition, actually, seismic damage can also appear when buried depth is deep under the cross influences of surrounding rock quality,high in-situ stress and fault.4. Research about safety influences of near-field seismic faults on tunnelEarthquake initiated by seismic fault of the engineering near field area is different from general far-field earthquake, which has long period and large velocity pulse. Due to the lack of seismic monitoring records, firstly, a near-fault pulse-type seismic record is generated synthetically using equivalent velocity pulse model combined with high-frequency earthquake compponents and real near-field seismic parameters, and then this artificial wave is used to simulate the quake induced by strike-slip fault movement near the tunnel portal using kinematic seismic source model, which can be applied to evaluated the safety of the tunnel. Besides, a preliminary study is also carried out about safety influences of earthquake-induced secondary fault movement on tunnel. Meanwhile, the safety influence of tunnel slope failure on the tunnel portal is evaluated as well.5. Research on tunnel aseismic methods in high seismic intensity area.Firstly, two general ideas about tunnel aseismic design are concluded,which are property change of rock surrounding of a certain range and property change of tunnel structure itself, and various anti-seismic and seismic-relieving measures of the tunnel now are all summarized according to the two ideas, then a series of studies are carried out on tunnel aseismic design methods, which inlude researches on sectional form optimization, shock absorption effects of seismic isolation layer, shock-reduction effects of surrounding rock strengthening and anti-breaking structural design.Among the research on seismic isolation layer, the shock absorption effect of foam concrete is verified through numerical experiment, using crushable-foam rate-dependent constitutive model. The result shows that foamed concrete has good shock absorption effects as seismic isolation layer of tunnel lining, meanwhile, an economic and areasonable thickness of the isolation layer is proposed according to the specific conditions of practical engineering. Besides, two ideas on earthquake reduction of isolation layer and traditional earthquake resistant of stiffness increment are compared specially. At last, summarizing the above work, some applicable suggestions are proposed on tunnel aseismic design.6. Seismic research and earthquake monitoring for Galongla TunnelUsing the above research results synthetically, research on Galongla Tunnel seismic response is carried out, evaluating the influences of both near-fault pulse-type earthquake and far-field earthquake on inlet region containing non-causative fault, then, anti-seismic and seismic-relieving measures suitable for Galongla Tunnel are proposed. Meanwhile, remote automatic earthquake monitoring of the tunnel is carried out. By burying accelerograph in inlet region of the tunnel, three-direction acceleration records can be obtained, which provide the first hand data about research on real tunnel seismic response.更多还原