Engineering Failure Analysis最新文献_第3页

Numerical study on the mechanical and deformation behavior of a shield tunnel under different geological conditions 不同地质条件下盾构隧道机械和变形行为的数值研究

IF 4.4 2区工程技术 Q1 ENGINEERING, MECHANICAL

Engineering Failure Analysis

Pub Date : 2024-10-23 DOI: 10.1016/j.engfailanal.2024.108984

Investigating the mechanical and deformation response of a shield tunnel to nearby cavities has a significant importance on the structural safety assessment and protection. Limited to the laborious modelling and analysis barriers, the refined structural model including lining segments and connecting bolts are proposed by the BIM-based parametric modelling technology, using which the geometric properties can be adjusted through one-click operation. The pretreatment algorithm has also been developed to impose springs on the numeric nodes effectively and accurately, forming an elaborate numerical simulation method. Numerical analysis has been exerted and verified considering the homogeneity of the excavation geological condition. Results show that for the shield tunnel excavated in the homogeneous stratum, the mechanical and deformation responses of the lining structure are symmetrical about the vertical central plane. The lining ring deforms from a circle to an elliptic shape. To inquire the effect of the geological cavity, three sceneries for cavity at various positions are studied. Numerical results reveal that the lining segments deform towards the cavity side significantly, leading to over 100 times the deformation increment at the vault and invert, even over 1000 times at the cavity side for the unilateral cavity. At the cavity(ies) side(s), the internal forces of the lining segments increase, and the stress states change from compression on the outer surface to tension. The stress of connecting bolts also indicates the stress concentration for the supporting structures at the cavity side. Reinforced supports are needed for the concrete linings near the geological defects.

研究盾构隧道对附近空洞的机械和变形响应对结构安全评估和保护具有重要意义。受限于繁琐的建模和分析障碍，基于 BIM 的参数化建模技术提出了包括衬砌段和连接螺栓在内的细化结构模型，通过一键操作即可调整几何属性。此外，还开发了预处理算法，可有效、准确地对数值节点施加弹簧，形成精细的数值模拟方法。考虑到开挖地质条件的均匀性，进行了数值分析和验证。结果表明，对于在均质地层中开挖的盾构隧道，衬砌结构的力学和变形响应围绕垂直中心平面对称。衬砌环从圆形变形为椭圆形。为了探究地质空洞的影响，研究了不同位置空洞的三种情况。数值结果显示，衬砌段向空腔一侧的变形非常明显，导致拱顶和反转处的变形增量超过 100 倍，单侧空腔一侧的变形增量甚至超过 1000 倍。在空腔侧，衬砌段的内力增加，应力状态从外表面的压缩变为拉伸。连接螺栓的应力也表明了空腔侧支撑结构的应力集中。地质缺陷附近的混凝土衬里需要加强支撑。

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引用次数: 0

Dynamic characteristics and damage identification with interface damage of slabs in movable point crossing 动点穿越中板坯界面损伤的动态特性和损伤识别

IF 4.4 2区工程技术 Q1 ENGINEERING, MECHANICAL

Engineering Failure Analysis

Pub Date : 2024-10-22 DOI: 10.1016/j.engfailanal.2024.108986

As the operating density of China’s high-speed railway increases, the phenomenon of interlayer debonding in movable point crossing (MPC) is becoming more prevalent, which can lead to failure of the frog’s slab track. Meanwhile, vehicle impacts and interlayer debonding can exacerbate abnormal vibration of the vehicle and even lead to derailment. Therefore, based on the theory of rigid-flexible coupling dynamics, a vehicle-turnout-slab coupling dynamics model is established for the first time. In this model, the crossing rails with variable cross sections is considered and the interlayer debonding between turnout slabs is modelled by nonlinear springs. Then, the characteristics of the debonding is identified by applying a wavelet transform to the dynamic response of the vehicle. Finally, different types and sizes of debonding between the layers are considered. The results show that different debonding can lead to two types of contact, partial contact and complete voiding, which can further lead to detrimental effects on vehicle safety. And the limit of the defect size that causes the track slab to void is 1 mm. On this basis, it was found that when MPC’s slab tracks were voided, longer debonding can cause high frequency vibration acceleration of approximately 700 Hz in the vehicle axle box. The new insights obtained by this study could provide guidance for the maintenance period and avoid the development of the damage. This study not only obtained a mechanism for the effect of interlayer debonding on the dynamic response of the vehicle-track system, but also provides a theoretical basis of detecting interlayer debonding for future study.

随着中国高速铁路运营密度的增加，活动道岔（MPC）的层间脱粘现象越来越普遍，这可能导致蛙板式轨道失效。同时，车辆撞击和层间脱粘会加剧车辆的异常振动，甚至导致脱轨。因此，基于刚柔耦合动力学理论，首次建立了车辆-道岔-板式耦合动力学模型。在该模型中，考虑了横截面可变的道岔钢轨，并用非线性弹簧模拟了道岔板间的层间脱粘。然后，通过对车辆的动态响应进行小波变换来确定脱胶的特征。最后，考虑了层间不同类型和大小的脱胶。结果表明，不同的脱胶会导致两种类型的接触，即部分接触和完全脱胶，从而进一步导致对车辆安全的不利影响。而导致轨道板失效的缺陷尺寸极限为 1 毫米。在此基础上，研究发现，当 MPC 的板式轨道出现空洞时，较长的脱粘会在车辆轴箱中造成约 700 Hz 的高频振动加速度。本研究获得的新见解可为维护期提供指导，避免损坏的发展。本研究不仅获得了层间脱粘对车辆-轨道系统动态响应影响的机理，还为今后的研究提供了检测层间脱粘的理论基础。

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引用次数: 0

Causes and analysis of failure of bearing cage at non-driven end of wind turbine generator 风力发电机非驱动端轴承保持架故障原因及分析

IF 4.4 2区工程技术 Q1 ENGINEERING, MECHANICAL

Engineering Failure Analysis

Pub Date : 2024-10-22 DOI: 10.1016/j.engfailanal.2024.108991

The non-driving end bearing cage of a wind turbine generator experienced a fracture and subsequent failure. In order to understand the reasons behind this failure, various analyses were conducted including examination of the metallographic structure, mechanical properties, fracture surface morphology, bearing vibration, and operating temperature of the cage. Through this analysis, the fracture process of the cage was deduced. The findings indicate that the fracture of the bearing cage was directly caused by the abnormal installation of the spacer. The eccentricity of the axial component resulted in ductile fracture, while the eccentricity of the radial component led to brittle fractures.

一台风力涡轮发电机的非驱动端轴承保持架发生断裂并随后失效。为了了解故障背后的原因，我们进行了各种分析，包括检查保持架的金相结构、机械性能、断口表面形态、轴承振动和工作温度。通过这些分析，推断出保持架的断裂过程。研究结果表明，轴承保持架断裂的直接原因是隔圈安装异常。轴向部件的偏心导致韧性断裂，而径向部件的偏心则导致脆性断裂。

引用次数: 0

Research on the failure mechanisms and preventive actions of tunnels under butterfly load in loess regions 黄土地区蝶形荷载下隧道破坏机理及预防措施研究

IF 4.4 2区工程技术 Q1 ENGINEERING, MECHANICAL

Engineering Failure Analysis

Pub Date : 2024-10-22 DOI: 10.1016/j.engfailanal.2024.108972

The results of surrounding rock pressure measurements from numerous loess tunnels exhibit a butterfly distribution pattern, subsequently referred to as ’butterfly load’. This pattern significantly deviates from the load distribution and magnitude—referred to as ’specification load’—calculated by current Chinese tunnel design specifications. By means of model experimental and numerical simulation, the mechanical behavior, failure cause, failure mechanism and preventive actions of tunnel structure under different load distribution are studied. The experimental results indicate that the ultimate bearing capacity of the tunnel structure under the butterfly load is significantly lower than that under the specification load, with the ultimate bearing capacity decreasing as load unevenness increases. The butterfly load increases the unevenness of the axial force distribution throughout the annular structure and also causes the structure to produce reverse moments in the vault and arch shoulder. Similarly, the morphological characteristics of the cracks show that the butterfly load most significantly influences the tunnel vault and arch shoulder. Under the influence of the butterfly load, the lining structure is prone to developing cracks at the arch shoulder and arch foot positions, with tensile cracks located at the vault position. Aiming at the failure mechanism of tunnel structure under butterfly load, it is suggested to implement advanced small conduit grouting at the tunnel arch to suppress the dislocation of the formation and to lay root piles at the arch foot to improve the bearing capacity of the tunnel bottom. The prevention effect of this technology in different loess regions is sandy loess > general loess > clay loess.

许多黄土隧道的围岩压力测量结果显示出一种蝶形分布模式，随后被称为 "蝶形荷载"。这种模式与中国现行隧道设计规范所计算的荷载分布和大小（即 "规范荷载"）存在明显偏差。通过模型试验和数值模拟，研究了不同荷载分布下隧道结构的力学行为、破坏原因、破坏机理和预防措施。实验结果表明，隧道结构在蝶形荷载作用下的极限承载力明显低于规范荷载作用下的极限承载力，且极限承载力随荷载不均匀度的增加而减小。蝶形荷载增加了整个环形结构轴向力分布的不均匀性，也导致结构在拱顶和拱肩产生反向力矩。同样，从裂缝的形态特征来看，蝶形荷载对隧道拱顶和拱肩的影响最大。在蝶形荷载的影响下，衬砌结构容易在拱肩和拱脚位置产生裂缝，而拉伸裂缝则位于拱顶位置。针对隧道结构在蝶式荷载作用下的破坏机理，建议在隧道拱部采用超前小导管注浆，抑制地层错动，并在拱脚打根桩，提高隧道底部承载力。该技术在不同黄土地区的防治效果分别为砂质黄土、一般黄土、粘土黄土。

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引用次数: 0

Investigating crack evolution, and failure precursor warning in sandstones with different water contents from the perspective of tensile-shear crack separation 从拉伸-剪切裂缝分离的角度研究不同含水量砂岩中的裂缝演变和破坏前兆预警

IF 4.4 2区工程技术 Q1 ENGINEERING, MECHANICAL

Engineering Failure Analysis

Pub Date : 2024-10-22 DOI: 10.1016/j.engfailanal.2024.108997

To investigate the effect of water on the crack evolution and damage mode of sandstone, uniaxial compression experiments were conducted using samples with different water contents. The damage evolution process of sandstones with different water contents was investigated based on acoustic emission (AE) and digital image correlation (DIC) techniques. Further, the crack evolution was conducted using the RA-AF distribution method. The results showed that the brittleness of sandstone weakened with increasing water content, and the uniaxial compressive strength (UCS) and elastic modulus decreased significantly. The percentage of shear cracks increased continuously from 21.1% when dry to 36.53% when saturated and the evolution of these cracks through AE signals correlates closely with DIC observations. However, the influence of water on the development of these cracks differs significantly. Through the separation analysis of the two types of cracks, the damage evolution law of sandstone is clearer. Based on the critical slowing down theory (CSDT), the point at which both tensile and shear crack signals undergo abrupt fluctuation serves as an early warning indicator. The early warning point identification results of the sandstone with different water contents are all in the crack extension stage, the stress levels are all near 0.9 and demonstrate reliable predictive capabilities. Furthermore, the mechanism of water’s impact on the transition of crack types and the differences in damage modes in sandstone during the initial and later loading stages is explained by analyzing the characteristics of tensile and shear crack emergence and expansion.

为了研究水对砂岩裂纹演变和破坏模式的影响，使用不同含水量的样品进行了单轴压缩实验。基于声发射（AE）和数字图像相关（DIC）技术，研究了不同含水量砂岩的破坏演化过程。此外，还采用 RA-AF 分布法对裂缝演变过程进行了研究。结果表明，砂岩的脆性随着含水量的增加而减弱，单轴抗压强度（UCS）和弹性模量显著下降。剪切裂缝的百分比从干燥时的 21.1% 持续增加到饱和时的 36.53%，这些裂缝通过 AE 信号的演变与 DIC 观察结果密切相关。然而，水对这些裂缝发展的影响却大不相同。通过对两种裂缝的分离分析，砂岩的损伤演变规律更加清晰。根据临界减速理论（CSDT），拉伸和剪切裂缝信号发生突然波动的点可作为预警指标。不同含水率砂岩的预警点识别结果均处于裂缝扩展阶段，应力水平均接近 0.9，显示了可靠的预测能力。此外，通过分析拉伸和剪切裂缝出现和扩展的特征，解释了水对砂岩裂缝类型转变的影响机理以及加载初期和后期破坏模式的差异。

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引用次数: 0

Model test study on the dynamic failure process of tunnel surrounding rocks in jointed rock mass under explosive load 爆炸荷载作用下节理岩体隧道围岩动态破坏过程的模型试验研究

IF 4.4 2区工程技术 Q1 ENGINEERING, MECHANICAL

Engineering Failure Analysis

Pub Date : 2024-10-22 DOI: 10.1016/j.engfailanal.2024.108996

The presence of joints can significantly reduce the integrity and stability of an engineering rock mass. Under dynamic loads, such as from blasting excavation, the key blocks divided by joints may be destabilized and prone to sliding, potentially leading to engineering geological disasters like rockbursts. To study the dynamic instability process, similar materials for the rock mass and joints were developed based on the similarity theory, and a tunnel model in the jointed rock mass was constructed. Subsequently, a detonating fuse was used to generate a dynamic load, and the dynamic instability process of the tunnel surrounding rock in the jointed rock mass under explosive load was studied using the geotechnical multifunctional testing device. The deformation characteristics and dynamic instability process of the tunnel surrounding rock were analyzed using acceleration sensors, resistance strain gages, linear variable displacement transducers and motion camera. The study shows that the acceleration at the tunnel vault is significantly greater than at the straight wall and floor under blast loads, with differences reaching an order of magnitude. Acceleration waveforms were classified into three categories based on peak characteristics, explained through the propagation of explosive stress waves. Additionally, strain and displacement at the tunnel arch were also significantly greater than in other areas, indicating more severe stress concentration and dynamic damage at the arch, necessitating reinforced support in tunnel excavation. The entire dynamic instability process of the tunnel surrounding rock was successfully recorded using a motion camera. The dynamic failure process was divided into several phases, the appearance of cracks on the joint surface, particle ejection accompanied by the dropping of jointed blocks, a significant drop of the jointed blocks, and return to calm. The dynamic failure modes include the dropping and rotation of jointed blocks, local particle ejection, and shear cracks on jointed block.

节理的存在会大大降低工程岩体的完整性和稳定性。在动荷载（如爆破开挖产生的荷载）作用下，被节理分割的关键岩块可能会失稳，容易发生滑动，从而可能导致岩爆等工程地质灾害。为了研究动态失稳过程，根据相似性理论开发了岩体和节理的相似材料，并在节理岩体中构建了隧道模型。随后，使用引爆引信产生动荷载，并利用岩土多功能试验装置研究了节理岩体中隧道围岩在爆炸荷载作用下的动不稳定过程。利用加速度传感器、电阻应变计、线性可变位移传感器和运动摄像机分析了隧道围岩的变形特征和动态失稳过程。研究表明，在爆破荷载作用下，隧道拱顶处的加速度明显大于直墙和底板处的加速度，差异达到一个数量级。加速度波形根据峰值特征分为三类，通过爆炸应力波的传播进行解释。此外，隧道拱部的应变和位移也明显大于其他区域，这表明拱部的应力集中和动态破坏更为严重，需要在隧道开挖时加强支护。使用运动摄像机成功记录了隧道围岩的整个动态失稳过程。动态破坏过程分为几个阶段：接合面出现裂缝、颗粒喷出并伴随接合块掉落、接合块明显掉落以及恢复平静。动态破坏模式包括接合块掉落和旋转、局部颗粒喷射和接合块上的剪切裂缝。

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引用次数: 0

Numerical and experimental study on corrosion mechanism of the water-oil two-phase flow in the atmospheric tower top system 大气塔顶系统中水油两相流腐蚀机理的数值和实验研究

IF 4.4 2区工程技术 Q1 ENGINEERING, MECHANICAL

Engineering Failure Analysis

Pub Date : 2024-10-22 DOI: 10.1016/j.engfailanal.2024.108981

The atmospheric tower is the main component of the crude oil refining units and is a critical area of concern due to the risk of corrosion failure. Research on the corrosion mechanism and risk protection of atmospheric tower top systems plays a vital role in the safe operation of refineries. In this paper, the water-oil two phase process flow of the atmospheric tower top system was simulated by Aspen software. A corresponding flow corrosion simulation experiment was designed according to the main characteristic parameters of the simulated stream. The experimental results under varying temperature and impact angle conditions were analyzed by using microanalysis technology and CFD simulation methods. The process and mechanism of corrosion failure of tower top system under ammonia salt and dew point corrosion environment are revealed in physicochemical aspects. The results show that the corrosion rate was highest at the dew point temperature, but as the temperature decreases, the corrosion products adsorbed and accumulated on the surface are more difficult to remove from the surface, which slows down the corrosion rate. When the impact angle increased from 0° to 60°, the increment of the surface fluid impact force and turbulence intensity makes the corrosion products easier to be stripped off, which enhances the mass transfer efficiency between the corrosive medium and the surface to accelerate the corrosion rate. Different phase states and flow modes affected the morphology of corrosion pits on the surface. The depth and size of the pits in only water phase corrosion were larger than those in the two-phase flow corrosion, Additionally, as the impact angle increased from 0°, the morphology of pits changes from a relatively flat pattern to a more undulating shape. The research results reveal the characteristics of the main corrosion types occurring in the atmospheric tower top system of the oil refining industry, and provide a reference for corrosion risk protection methods.

常压塔是原油精炼装置的主要组成部分，由于存在腐蚀失效的风险，因此是一个备受关注的重要领域。研究常压塔塔顶系统的腐蚀机理和风险防护对炼油厂的安全运行起着至关重要的作用。本文利用 Aspen 软件模拟了常压塔顶系统的水油两相工艺流程。根据模拟流的主要特征参数，设计了相应的流动腐蚀模拟实验。利用显微分析技术和 CFD 模拟方法分析了不同温度和冲击角条件下的实验结果。从物理化学方面揭示了氨盐和露点腐蚀环境下塔顶系统腐蚀失效的过程和机理。结果表明，在露点温度下腐蚀速率最高，但随着温度的降低，表面吸附和积累的腐蚀产物更难从表面去除，从而减缓了腐蚀速率。当冲击角从 0°增加到 60°时，表面流体冲击力和湍流强度的增加使腐蚀产物更容易被剥离，从而提高了腐蚀介质与表面之间的传质效率，加快了腐蚀速率。不同的相态和流动模式影响着表面腐蚀坑的形态。此外，随着撞击角从 0°增大，腐蚀坑的形态也从相对平坦的形态变为起伏较大的形态。研究结果揭示了炼油工业大气塔顶系统中发生的主要腐蚀类型的特征，为腐蚀风险防护方法提供了参考。

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引用次数: 0

Failure analysis in pyrolysis furnaces: Impact of carburization and thermal cycles on tube properties 热解炉的失效分析：渗碳和热循环对钢管性能的影响

IF 4.4 2区工程技术 Q1 ENGINEERING, MECHANICAL

Engineering Failure Analysis

Pub Date : 2024-10-22 DOI: 10.1016/j.engfailanal.2024.109000

The dominant failure mechanism in radiation coil tubes in pyrolysis furnaces is the detrimental interaction between carburization and reduced material ductility. This combination results in localized deformations, significant ovalization, and cracking in the tubes. At the same time, a second critical failure mechanism emerges during emergency furnace shutdowns, characterized by brittle fractures that can generate extensive longitudinal cracks in multiple tubes. This work presents a case study on the occurrence of failures that resulted in brittle fracture rupture of several tubes in a pyrolysis furnace that accumulated 43,720 h of operation. This highlights the practical importance of monitoring and managing the integrity of coil tubes. The tube samples were analyzed using optical and scanning electron microscopy, evaluation of carburization through magnetic permeability and NACE Test TM498, identification of carbides by X-ray diffraction (XRD), and dilatometry. Additionally, thermal stress analyses were performed using the finite element method, along with tensile tests at different temperatures. It was found that the tubes of the coil that operated at lower temperatures in their operational cycle did not rupture during the emergency shutdown, unlike other coils whose tubes experienced significant failures. An important contribution from this study is the demonstration of optimized operational cycle management and thermal control are essential in preserving protective oxide layers, minimizing coke formation and the effects of carburization and creep. This can reduce shutdown frequency and maintenance costs, improving the cost-effectiveness of the cracking process.

热解炉中辐射线圈管的主要失效机制是渗碳和材料延展性降低之间的有害相互作用。这种相互作用会导致管子局部变形、严重椭圆化和开裂。与此同时，在紧急停炉时还会出现第二种关键失效机制，其特点是脆性断裂，可在多根管子中产生广泛的纵向裂缝。这项工作介绍了一个案例研究，该案例研究了在一个累计运行 43,720 小时的热解炉中发生的导致多根管子脆性断裂的故障。这凸显了监测和管理线圈管完整性的实际重要性。使用光学显微镜和扫描电子显微镜对钢管样品进行了分析，通过磁导率和 NACE 测试 TM498 对渗碳情况进行了评估，通过 X 射线衍射 (XRD) 和扩张度测量对碳化物进行了鉴定。此外，还使用有限元法进行了热应力分析，并在不同温度下进行了拉伸试验。研究发现，在运行周期中温度较低的线圈管在紧急停机时没有破裂，而其他线圈管则出现了严重故障。这项研究的一个重要贡献是证明了优化运行周期管理和热控制对于保护氧化层、最大限度地减少焦炭形成以及渗碳和蠕变的影响至关重要。这可以降低停机频率和维护成本，提高裂化工艺的成本效益。

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引用次数: 0

Modeling the bond–slip behavior of the interface between a stiffened core and cemented soil based on machine learning approaches 基于机器学习方法的加劲核心与胶结土界面粘结滑动行为建模

IF 4.4 2区工程技术 Q1 ENGINEERING, MECHANICAL

Engineering Failure Analysis

Pub Date : 2024-10-22 DOI: 10.1016/j.engfailanal.2024.108992

The bond–slip behavior of stiffened deep cement mixing (SDCM) piles—which is crucial for their bearing capacity—evolves continuously with curing age. In the study reported here, 20 element tests were conducted on the interface between cemented soil and a stiffened core, analyzing the bond–slip behavior affected by curing temperature and age, and then ensemble learning methods (XGBoost, random forest) were used to establish models for the evolution of the bond–slip behavior considering thermal effects. The constructed models can predict the peak shear strength (τ_max), the residual shear strength (τ_res), and the interfacial shear modulus (G). The test results show that the shear strength of the stiffened-core–cemented-soil interface grows with the increasing curing temperature and age, with faster growth at 0–14 days compared to 60–90 days. To lessen the reliance on ineffective brute-force searching, Bayesian optimization with a tree-structured Parzen estimator is used to select the hyperparameters of the established models. The results demonstrate the superior performance of the chosen approach, with R² > 0.93 for the training set and R² > 0.81 for the test set. The results of the XGBoost model are best for τ_max, with a mean absolute percentage error of less than 5 %, thereby enabling accurate predictions of the mechanical parameters of the stiffened-core–cemented-soil. This research enhances the understanding of the mechanical properties of SDCM piles and provides valuable guidance for projects involving such piles.

加劲深层水泥搅拌桩（SDCM）的粘结滑移行为对其承载能力至关重要，并随着固化龄期的变化而不断变化。在本文所报告的研究中，对水泥土和加劲核心筒之间的界面进行了 20 次元素试验，分析了受固化温度和龄期影响的粘结滑移行为，然后使用集合学习方法（XGBoost、随机森林）建立了考虑热效应的粘结滑移行为演变模型。所建模型可预测峰值剪切强度（τmax）、残余剪切强度（τres）和界面剪切模量（G）。试验结果表明，加劲芯材-加固土界面的剪切强度会随着固化温度和龄期的增加而增加，0-14 天与 60-90 天相比增长更快。为了减少对无效蛮力搜索的依赖，使用了贝叶斯优化和树状结构的 Parzen 估计器来选择已建立模型的超参数。结果表明所选方法性能优越，训练集的 R2 > 为 0.93，测试集的 R2 > 为 0.81。XGBoost 模型对 τmax 的结果最好，平均绝对百分比误差小于 5%，因此能够准确预测加筋芯材加固土的力学参数。这项研究加深了对 SDCM 桩力学性能的理解，为涉及此类桩的项目提供了有价值的指导。

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引用次数: 0

Failure analysis and deformation characteristics of shield tunnel obliquely crossing ground fissure under earthquake 地震下斜交地裂缝盾构隧道的破坏分析与变形特征

IF 4.4 2区工程技术 Q1 ENGINEERING, MECHANICAL

Engineering Failure Analysis

Pub Date : 2024-10-21 DOI: 10.1016/j.engfailanal.2024.108990

In order to study the deformation law and failure characteristics of shield tunnel obliquely crossing ground fissure under earthquake action, taking the shield tunnel of Xi ’an Metro Line 8 crossing f₃ ground fissure as the engineering background, the 1: 20 shaking table model test method was used to analyze the strain of shield tunnel, the contact pressure with surrounding rock soil, the dislocation of segment and the axial force of bolt in detail, and the seismic damage mechanism and failure characteristics of shield tunnel obliquely crossing ground fissure were obtained. The test results show that under the action of earthquake, the shield tunnel has complex three-dimensional deformation characteristics, among which the vertical deformation is the most obvious. The deformation is mainly concentrated in the location of the ground fissure. The tensile strain and contact pressure of the hanging wall of the tunnel segment are greater than the strain value and contact pressure of the footwall. Because the vertical deformation of the tunnel is the largest, the bolts at the vault and the arch bottom are most obviously pulled. Excavation after the test, it can be seen that the tunnel appeared the phenomenon of ring joint opening, lining cracking and other damage. Under the action of the earthquake, the shield tunnel across the ground fissure is mainly subjected to tensile failure. The failure area is within 10 m from the ground fissure in the hanging wall and footwall, and the total length is 20 m. The closer to the ground fissure, the more serious the damage. The research results provide a scientific and reasonable reference for the subsequent construction and disaster prevention and mitigation design of Xi ’an Metro.

为研究盾构隧道斜穿地裂缝在地震作用下的变形规律和破坏特征，以西安地铁八号线盾构隧道穿越f3地裂缝为工程背景，采用1：20振动台模型试验方法，详细分析了盾构隧道的应变、与围岩土体的接触压力、节段变位和螺栓轴力等，得到了盾构隧道斜穿地裂缝的震害机理和破坏特征。试验结果表明，在地震作用下，盾构隧道具有复杂的三维变形特征，其中垂直变形最为明显。变形主要集中在地裂缝位置。隧道段悬壁的拉应变和接触压力大于底壁的应变值和接触压力。由于隧道的垂直变形最大，拱顶和拱底的螺栓受拉最明显。试验后开挖，可以看到隧道出现了环缝张开、衬砌开裂等破坏现象。在地震作用下，穿越地裂缝的盾构隧道主要是受拉破坏。破坏区域在悬壁和底壁距地裂缝 10 米范围内，总长度为 20 米，越靠近地裂缝破坏越严重。研究成果为西安地铁后续建设和防灾减灾设计提供了科学合理的参考。

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