Tunnelling and Underground Space Technology最新文献_第6页

Efficient automated method for characterizing discontinuities in tunnel face rock mass point clouds 表征隧道工作面岩体点云不连续性的高效自动方法

IF 6.7 1区工程技术 Q1 CONSTRUCTION & BUILDING TECHNOLOGY

Tunnelling and Underground Space Technology

Pub Date : 2024-10-08 DOI: 10.1016/j.tust.2024.106117

Current methods for identifying discontinuities in rock mass point clouds do not fully consider the unique characteristics of tunnel face rock masses. Excavation profiles reduce the accuracy of discontinuity characterization, and the short exposure time of tunnel face rock masses necessitates more efficient identification methods to guide excavation and support strategies. To address these issues, this paper proposes a new method for quickly characterizing discontinuities in tunnel face rock mass point clouds. This method automatically calculates the optimal tunnel face plane and uses distance thresholds to segment the tunnel face rock mass area from the excavation profile area, eliminating the influence of excavation profiles. Additionally, an optimized fuzzy C-means (OFCM) algorithm is designed to improve the accuracy and efficiency of discontinuity identification. The superiority of this method is demonstrated through three examples: polyhedral point clouds, a slope rock mass, and a tunnel face rock mass. In the slope point cloud test, the proposed method resulted in a dip difference of 2° and a dip direction difference of 0.6° compared with the DSE method, with an identification time of 52 s, compared with 7 min and 15 s for the DSE method. In a real tunnel face application in northwestern China, the proposed method showed an average difference from manual field measurements of 4.8° in the dip direction and 5° in the dip direction, with an identification time of 19 s, compared with 2 min and 52 s for the DSE method. Finally, this paper discusses the impact of distance threshold selection on the segmentation results and further verifies the method’s generality through applications on four other tunnel faces. These results indicate that the proposed method is highly accurate and efficient in identifying discontinuities in tunnel face rock masses and can be effectively applied in practical engineering.

目前在岩体点云中识别不连续性的方法并没有充分考虑到隧道工作面岩体的独特性。开挖剖面降低了不连续性特征描述的准确性，而隧道面岩体的暴露时间较短，因此需要更有效的识别方法来指导开挖和支护策略。为解决这些问题，本文提出了一种新方法，用于快速鉴定隧道工作面岩体点云中的不连续性。该方法可自动计算最佳隧道工作面平面，并使用距离阈值将隧道工作面岩体区域与开挖剖面区域分割开来，从而消除开挖剖面的影响。此外，还设计了一种优化的模糊 C-means (OFCM) 算法，以提高不连续性识别的准确性和效率。该方法的优越性通过三个实例得到了证明：多面体点云、斜坡岩体和隧道面岩体。在斜坡点云测试中，与 DSE 方法相比，拟议方法的倾角差为 2°，倾角方向差为 0.6°，识别时间为 52 秒，而 DSE 方法的识别时间为 7 分钟和 15 秒。在中国西北部的一个实际隧道工作面应用中，所提出的方法与人工现场测量结果相比，在倾角方向上的平均差异为 4.8°，在倾角方向上的平均差异为 5°，识别时间为 19 秒，而 DSE 方法的识别时间为 2 分钟 52 秒。最后，本文讨论了距离阈值选择对分割结果的影响，并通过在其他四个隧道面上的应用进一步验证了该方法的通用性。这些结果表明，所提出的方法在识别隧道工作面岩体的不连续性方面具有很高的准确性和效率，可以有效地应用于实际工程中。

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引用次数: 0

Seizing the opportunity of energy retrofitting of existing tunnels 抓住现有隧道节能改造的机遇

IF 6.7 1区工程技术 Q1 CONSTRUCTION & BUILDING TECHNOLOGY

Tunnelling and Underground Space Technology

Pub Date : 2024-10-08 DOI: 10.1016/j.tust.2024.106109

Energy tunnels have emerged as systems that can contribute to the production of clean, renewable thermal energy. Nevertheless, so far applications have been related almost exclusively to new tunnelling projects. Accordingly, no systematic methodologies for the heat exchange instrumentation of existing tunnels have been proposed up until now. Starting from the valuable experience gained from different energy tunnel testbeds worldwide, this paper proposes two approaches that would allow the thermal activation of the existing heritage of tunnels. Different solutions are conceived for both approaches to fit various existing tunnel decay contexts and diverse levels of refurbishment necessity. These are illustrated, outlining characteristics and advantages, describing expected installation details and issues and analysing the possibility of real implementations. The geothermal potential of such solutions is assessed through thermo-hydraulic numerical modelling. Finally, with the aim of investigating their economic attractiveness and profitability, a brief economic analysis is drawn up, considering the geothermal energy produced and the costs involved in installing and running the systems.

能源隧道是一种有助于生产清洁、可再生热能的系统。然而，迄今为止，其应用几乎只与新隧道项目有关。因此，到目前为止，还没有提出对现有隧道进行热交换测量的系统方法。本文从世界各地不同的能源隧道试验台获得的宝贵经验出发，提出了两种可对现有隧道遗产进行热激活的方法。本文为这两种方法设想了不同的解决方案，以适应各种现有隧道的衰变情况和不同程度的翻新需要。本文对这些方案进行了说明，概述了其特点和优势，描述了预期的安装细节和问题，并分析了实际实施的可能性。通过热-水力数值建模评估了这些解决方案的地热潜力。最后，为了研究这些方案的经济吸引力和盈利能力，考虑到所产生的地热能以及安装和运行这些系统所涉及的成本，还进行了简要的经济分析。

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引用次数: 0

Numerical implementation of a hydraulic interaction creep model and its application to the support reinforcement of water-rich cracked tunnel 水力相互作用蠕变模型的数值实施及其在富水裂缝隧道支护加固中的应用

IF 6.7 1区工程技术 Q1 CONSTRUCTION & BUILDING TECHNOLOGY

Tunnelling and Underground Space Technology

Pub Date : 2024-10-08 DOI: 10.1016/j.tust.2024.106098

To solve the problem of cracks in the secondary lining of the Yanglin Tunnel caused by the creep of water-rich surrounding rock, this study established a rock creep model of hydraulic interaction based on rock creep theory, fractional calculus theory, damage mechanics theory, and effective stress principle. Based on the secondary development module of the numerical computation software, a rock creep model of hydraulic interaction was embedded in the software to verify the model. In addition, a new support scheme was developed using the convergence-confinement and orthogonal experimental methods. Furthermore, a newly developed rock creep model was used to conduct a numerical simulation analysis of the new support scheme for the cracked section of the secondary lining of the Yanglin Tunnel under hydraulic interaction, verifying the long-term stability of the new support. The results were as follows. (1) Under hydraulic interaction, the established rock creep model effectively simulated the creep calculation process of standard rock samples, and the numerical calculation results were consistent with the experimental results. (2) The new support scheme significantly controlled the displacement changes in the surrounding rock and significantly reduced the growth rate of the crown displacement and clearance convergence. The final numerical calculation results converged and the displacement stabilized, indicating that the new support scheme had an ideal controlling effect on the displacement of the surrounding rock. (3) A numerical simulation analysis was conducted to optimize the support for the cracked section of the tunnel lining using a developed rock creep model under hydraulic interaction. The calculation results aligned with the actual engineering requirements, indicating that the rock creep model under the hydraulic interaction of secondary development can effectively simulate the creep calculation process of tunnel construction, thereby reflecting the validity and accuracy of the program. The proposed support scheme was applied to the reconstruction of a cracked section of the secondary lining of the Yanglin Tunnel.

为解决富水围岩蠕变引起的杨林隧道二次衬砌裂缝问题，本研究基于岩石蠕变理论、分数微积分理论、损伤力学理论和有效应力原理，建立了水力相互作用岩石蠕变模型。基于数值计算软件的二次开发模块，在软件中嵌入了水力相互作用的岩石蠕变模型，对模型进行了验证。此外，还利用收敛强化法和正交实验法开发了一种新的支撑方案。此外，利用新开发的岩石蠕变模型，对水力作用下杨林隧道二次衬砌开裂段的新支护方案进行了数值模拟分析，验证了新支护的长期稳定性。结果如下(1）在水力作用下，建立的岩石蠕变模型有效模拟了标准岩样的蠕变计算过程，数值计算结果与试验结果一致。(2）新的支护方案明显控制了围岩的位移变化，显著降低了冠部位移和间隙收敛的增长率。最终数值计算结果收敛，位移趋于稳定，表明新支护方案对围岩位移的控制效果理想。(3) 利用建立的水力作用下岩石蠕变模型，对隧道衬砌开裂段的支护进行了数值模拟分析优化。计算结果与实际工程要求相符，表明二次开发水力作用下的岩石蠕变模型能有效模拟隧道施工的蠕变计算过程，从而体现了方案的有效性和准确性。提出的支护方案被应用于杨林隧道二次衬砌裂缝段的重建。

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引用次数: 0

Rheological characteristics and model applicability of shield tunnel backfilling grouts with supplementary cementitious materials 含有补充胶凝材料的盾构隧道回填注浆的流变特性和模型适用性

IF 6.7 1区工程技术 Q1 CONSTRUCTION & BUILDING TECHNOLOGY

Tunnelling and Underground Space Technology

Pub Date : 2024-10-08 DOI: 10.1016/j.tust.2024.106121

Rheological properties are essential in determining how effective grouting is during the shield tunneling process. Additionally, they form the basis for developing penetration and diffusion models for grout in the surrounding layers. Despite extensive research on the rheological properties of traditional cement-based grouts informing engineering practices, the specific influence patterns and mechanisms related to the rheological properties of grout mixtures containing three industrial solid wastes—fly ash (FA), silica fume (SF), and ground granulated blast furnace slag (GGBS)—as supplementary cementitious materials (SCMs) remain poorly understood. Therefore, this study conducted rheological tests on fresh grout by a new advanced rheometer MCR302e, varying the content of FA, SF, and GGBS.

Results show that the modified Bingham and Herschel-Bulkley models proved more effective than the Bingham model in characterizing the rheological behavior of fresh grout. The modified Bingham model demonstrates superior applicability among these models, while the Herschel-Bulkley model presents better stability. The yield stress and plastic viscosity initially increase and then decrease with the addition of FA and GGBS, whereas, with SF, they show a decreasing trend followed by an increase. The thixotropy initially increases and then decreases with the addition of FA and GGBS while it continuously increases with the addition of SF. Furthermore, experimental results demonstrate that including 60% FA content alone results in the most significant improvement in the rheological properties of fresh grout. Compared to using just 60 % FA, the mix of FA and SF mostly increases the yield stress, while the mix of FA and GGBS mainly increases the plastic viscosity. For shield tunnel construction in Nanning, it is recommended to use more than 60% FA, over 2% SF, and no more than 20% GGBS.

流变特性对于确定盾构掘进过程中的注浆效果至关重要。此外，流变特性也是开发周围地层中灌浆的渗透和扩散模型的基础。尽管对传统水泥基灌浆料流变特性的广泛研究为工程实践提供了参考，但对于含有粉煤灰 (FA)、硅灰 (SF) 和磨细高炉矿渣 (GGBS) 这三种工业固体废弃物作为辅助胶凝材料 (SCM) 的灌浆料混合物，其流变特性的具体影响模式和相关机制仍然知之甚少。因此，本研究使用新型先进的流变仪 MCR302e，在改变 FA、SF 和 GGBS 含量的情况下，对新鲜灌浆料进行了流变试验。结果表明，在表征新鲜灌浆料的流变行为方面，修正宾汉模型和赫歇尔-布克利模型比宾汉模型更有效。在这些模型中，改良宾汉模型的适用性更强，而赫歇尔-布克利模型的稳定性更好。加入 FA 和 GGBS 后，屈服应力和塑性粘度先增大后减小，而加入 SF 后则呈现先减小后增大的趋势。触变性随着 FA 和 GGBS 的添加先增大后减小，而随着 SF 的添加则持续增大。此外，实验结果表明，仅添加 60% 的 FA 就能显著改善新鲜灌浆料的流变特性。与只使用 60% 的 FA 相比，FA 和 SF 的混合主要增加了屈服应力，而 FA 和 GGBS 的混合主要增加了塑性粘度。在南宁盾构隧道施工中，建议使用 60% 以上的 FA、2% 以上的 SF 和不超过 20% 的 GGBS。

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引用次数: 0

The influence of constitutive models for sprayed concrete on the design of tunnel junctions 喷射混凝土结构模型对隧道交界处设计的影响

IF 6.7 1区工程技术 Q1 CONSTRUCTION & BUILDING TECHNOLOGY

Tunnelling and Underground Space Technology

Pub Date : 2024-10-08 DOI: 10.1016/j.tust.2024.106113

This study presents a comprehensive analysis of numerical modelling techniques applied to the design and assessment of sprayed concrete-lined (SCL) tunnel junctions, focusing on the lining performance. The approach integrates advanced constitutive models to simulate both ground and lining responses, aiming to provide a robust understanding of tunnel behaviour under a realistically simulated construction sequence. Notable features of the modelling approach include nonlinear elastoplastic models for ground strata, depth-varying properties, variable K0 and pore pressure profiles, and step-by-step construction of cross-passages. The constitutive models for the ground have been validated against real site data, employing moderately conservative input parameters to ensure realistic comparisons with monitoring data.

Results from numerical modelling offer insights into the lining movements, strains and loads at tunnel junctions. Notably, the choice of constitutive model for the lining significantly influences predicted behaviour, with nonlinear elastic models generally exhibiting larger but more localised movements and strains compared to linear elastic models. Furthermore, the study suggests potential optimisations in tunnel design, such as the reduction or elimination of reinforcement in thickening layers, based on the enhanced understanding provided by 3D numerical modelling. This underscores the value of this approach when considering environmental factors, such as carbon footprint reduction, in the design process.

本研究对应用于喷射混凝土衬砌（SCL）隧道交界处设计和评估的数值建模技术进行了全面分析，重点关注衬砌性能。该方法集成了先进的构成模型，可模拟地面和衬砌的响应，旨在提供对真实模拟施工顺序下隧道行为的可靠理解。建模方法的显著特点包括地层的非线性弹塑性模型、随深度变化的特性、可变的 K0 和孔隙压力剖面，以及交叉通道的分步施工。地层构成模型已根据实际现场数据进行了验证，采用了适度保守的输入参数，以确保与监测数据进行真实的比较。值得注意的是，衬砌构成模型的选择对预测行为有很大影响，与线性弹性模型相比，非线性弹性模型通常表现出更大但更局部的移动和应变。此外，该研究还提出了隧道设计的潜在优化方案，例如在三维数值建模所提供的更深入理解的基础上，减少或取消加厚层中的钢筋。这强调了这种方法在设计过程中考虑减少碳足迹等环境因素时的价值。

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引用次数: 0

Reliable simulation analysis for high-temperature inrush water hazard based on the digital twin model of tunnel geological environment 基于隧道地质环境数字孪生模型的高温涌水危害可靠模拟分析

IF 6.7 1区工程技术 Q1 CONSTRUCTION & BUILDING TECHNOLOGY

Tunnelling and Underground Space Technology

Pub Date : 2024-10-08 DOI: 10.1016/j.tust.2024.106110

In complex mountainous terrains, tunnel construction faces unique challenges from high-temperature water inrush hazards, a systemic risk arising from the interplay of stress, seepage, and temperature fields. Traditional simulation methods, focusing on isolated disaster scenarios, fall short in addressing the multifaceted nature of these risks due to geological ambiguity and data incompleteness. Digital twin technology presents an effective solution to these challenges; however, its core challenge lies in how to utilize digital twin technology for data-model-co-driven simulation analysis of coupled multi-physical fields in situations of incomplete data. This paper introduces a digital twin paradigm for the simulation analysis of water inrush, which significantly enhances efficiency and accuracy through the integration of advanced machine learning and finite element analysis techniques. Specifically, this is achieved by combining a high-precision geological modeling method based on Gaussian Processes (GP) with a parameter calibration method through Gaussian Process-Differential Evolution (GP-DE) back-analysis. Firstly, a voxel structure is utilized to integrate the multi-field attribute features of the tunnel environment. Secondly, through the integration of multi-source advanced geological prediction data, we construct a dynamic digital twin model of the tunnel environment leveraging machine learning techniques. To overcome the issue of low modeling accuracy, the GP is employed, enhancing the exploitation of latent information within multi-source geophysical data. Lastly, we utilize the GP-DE back-analysis method to calibrate the parameters of the tunnel environment, thereby enhancing the precision and reliability of water inrush simulations. The method has been validated through application to a section of an ultra-high-temperature water inrush tunnel in China, featuring a burial depth of 230 meters. The accuracy of the method is corroborated by the monitoring data from the tunnel, supporting dynamic optimization design and safety prevention measures during construction.

在复杂的山区地形中，隧道施工面临着高温水涌入危险的独特挑战，这是应力场、渗流场和温度场相互作用产生的系统风险。传统的模拟方法侧重于孤立的灾害场景，由于地质模糊和数据不完整，无法应对这些风险的多面性。数字孪生技术是应对这些挑战的有效解决方案，但其核心挑战在于如何在数据不完整的情况下，利用数字孪生技术对耦合的多物理场进行数据-模型-协同驱动的模拟分析。本文介绍了一种用于水涌模拟分析的数字孪生范例，该范例通过整合先进的机器学习和有限元分析技术，显著提高了效率和精度。具体来说，这是通过将基于高斯过程（GP）的高精度地质建模方法与通过高斯过程-微分演化（GP-DE）反向分析的参数校准方法相结合来实现的。首先，利用体素结构整合隧道环境的多场属性特征。其次，通过整合多源高级地质预测数据，利用机器学习技术构建隧道环境的动态数字孪生模型。为了克服建模精度低的问题，我们采用了 GP，加强了对多源地球物理数据中潜在信息的利用。最后，我们利用 GP-DE 反向分析方法来校准隧道环境参数，从而提高涌水模拟的精度和可靠性。该方法已通过应用于中国一个埋深 230 米的超高温涌水隧道段进行了验证。隧道的监测数据证实了该方法的准确性，为施工期间的动态优化设计和安全预防措施提供了支持。

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引用次数: 0

A unified constitutive model for salt rocks under triaxial creep-fatigue loading conditions 三轴蠕变-疲劳加载条件下盐岩的统一构造模型

IF 6.7 1区工程技术 Q1 CONSTRUCTION & BUILDING TECHNOLOGY

Tunnelling and Underground Space Technology

Pub Date : 2024-10-07 DOI: 10.1016/j.tust.2024.106116

The salt cavern compressed air energy storage (CAES) reservoir undergoes periodic cyclic gas injection and production, which induce coupled fatigue-creep effects on the surrounding rock during operation. In this work, a new constitutive model was developed for salt rocks, and it uses the traditional Norton model to describe the hardening degree with state variables. The fatigue-creep mechanical properties were investigated, the model was validated, and the model parameters were analyzed using triaxial continuous and interval fatigue tests. The findings were as followed: (1) Increasing the time interval will result in a higher residual strain and a shorter fatigue life; the confining pressures increases the compressive strength of salt rock. (2) The model only needs to adjust two parameters to accurately fit the fatigue-creep deformations behavior of salt rock, and it effectively characterizes the relationship between deformation and stress routes. (3) In the model, parameters m and k play a role through state variables. Parameter m affects the magnitude of the overall deformation and the length of the deceleration stage. Parameter k controls the bending of the curve, and has a more sensitive influence on the model. (4) Compared with that of the continuous fatigue model, the floating range of parameters m and k in the interval fatigue model is less than 10%. The model can adapt to the influence of time interval on rock deformation and more accurately predict the deformations of the salt rock surrounding the salt cavern reservoir.

盐穴压缩空气储能（CAES）储层在运行过程中会经历周期性的循环注气和生产，从而对围岩产生耦合疲劳-蠕变效应。在这项工作中，针对盐岩开发了一种新的构成模型，该模型采用传统的诺顿模型，用状态变量来描述硬化程度。研究了疲劳-蠕变力学性能，验证了模型，并使用三轴连续和间歇疲劳试验分析了模型参数。研究结果如下(1) 增加时间间隔会导致残余应变增加，疲劳寿命缩短；约束压力会增加盐岩的抗压强度。(2）该模型只需调整两个参数即可准确拟合盐岩的疲劳-蠕变变形行为，并有效表征了变形与应力路线之间的关系。 3）在该模型中，参数 m 和 k 通过状态变量发挥作用。参数 m 影响整体变形的大小和减速阶段的长度。参数 k 控制着曲线的弯曲程度，对模型的影响更为敏感。(4) 与连续疲劳模型相比，区间疲劳模型中参数 m 和 k 的浮动范围小于 10%。该模型能适应时间间隔对岩石变形的影响，能更准确地预测盐穴储层周围盐岩的变形。

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引用次数: 0

Anchorage mechanism and parametric analysis of a novel interface-shear-stress-dispersing bolt 新型界面剪应力分散螺栓的锚固机理和参数分析

IF 6.7 1区工程技术 Q1 CONSTRUCTION & BUILDING TECHNOLOGY

Tunnelling and Underground Space Technology

Pub Date : 2024-10-06 DOI: 10.1016/j.tust.2024.106118

Squeezed large deformation of surrounding rock is frequently encountered in high geo-stress soft rock projects. Conventional bolt support often encounters the problems of insufficient anchorage force or anchors being pulled out, which seriously affects the safety of deep soft rock projects. In view of this, this study develops a novel interface-shear-stress-dispersing (ISSD) bolt with high strength and excellent deformability. The ISSD bolt is composed of the smooth rebar, rough rebar, and anchors, where the smooth rebar is further divided into several segments by anchors. The anchor consists of a hollow cylinder with a height of 0.10 m, whose inner diameter is equal to the diameter of smooth rebar (D₁) while outer diameter (D₂) matches the diameter of borehole (D₃). Analysis of the anchorage mechanism of the ISSD bolt confirms that the anchors increase the distribution range of interface shear stress during the load transfer process. In addition, the free stretching of smooth rebar improves the ability of the ISSD bolt to resist the large deformation of surrounding rock, which makes it more suitable for weak surrounding rock with low anchorage interface strength. Optimization analysis of the anchor parameters (i.e., number, shape) reveals that increasing the number of anchors improves the anchorage force and pull-out displacement of the ISSD bolt. However, excessive anchors lead to the risk of progressive failure of anchorage interface, thus weakening the anchorage force of the ISSD bolt and its ability to resist deformation. The 4-m long ISSD bolt with two anchors performs best. An increase in the filling degree F (D₁/D₃) and end inclination angle α of the anchor not only improves the anchorage performance of the ISSD bolt, but also improves the stress uniformity of the grouting layer. The anchor with a F of 0.75 and a α of 45° is the most suitable for the ISSD bolt.

在高地质应力软岩工程中，经常会遇到围岩挤压大变形的情况。传统的螺栓支护往往会遇到锚固力不足或锚杆被拔出的问题，严重影响深层软岩工程的安全。有鉴于此，本研究开发了一种新型的界面剪应力分散（ISSD）螺栓，具有高强度和优异的变形能力。ISSD 螺栓由光滑钢筋、粗糙钢筋和锚杆组成，其中光滑钢筋又被锚杆分成若干段。锚由一个 0.10 米高的空心圆柱体组成，其内径等于光滑钢筋直径（D1），外径（D2）与钻孔直径（D3）相匹配。对 ISSD 螺栓锚固机理的分析表明，在荷载传递过程中，锚固件增加了界面剪应力的分布范围。此外，光滑钢筋的自由拉伸提高了 ISSD 螺栓抵抗围岩大变形的能力，使其更适用于锚固界面强度较低的软弱围岩。对锚杆参数（如数量、形状）的优化分析表明，增加锚杆数量可提高 ISSD 螺栓的锚固力和拉拔位移。然而，过多的锚固件会导致锚固界面逐渐失效的风险，从而削弱 ISSD 螺栓的锚固力和抵抗变形的能力。带有两个锚固件的 4 米长 ISSD 螺栓性能最佳。增加锚杆的填充度 F（D1/D3）和端部倾角 α 不仅能提高 ISSD 螺栓的锚固性能，还能改善灌浆层的应力均匀性。F 值为 0.75、α 为 45° 的锚栓最适合 ISSD 螺栓。

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引用次数: 0

Intelligent detection of underground openings and surrounding disturbed zones 智能探测地下洞口和周围受干扰区域

IF 6.7 1区工程技术 Q1 CONSTRUCTION & BUILDING TECHNOLOGY

Tunnelling and Underground Space Technology

Pub Date : 2024-10-05 DOI: 10.1016/j.tust.2024.106122

This study aims to develop an intelligent method to detect subsurface anomalies for prediction and mitigation of geologic risks. We trained a convolutional neural network (CNN) model using the seismic data from 6 field cases of regular pipes and irregular cavities and a sliding time window technique to augment the datasets, and tested the CNN model using another 2 field cases. We derived probability distribution as an indicator of anomaly existence and validated high-value and low-value probability distributions corresponding to underground openings and surrounding disturbed zones, respectively. We found that the characteristics of subsurface anomalies determines the effective seismic features and influences the CNN model performance. Finally, we applied the CNN model to investigate a circular-bored tunnel and surrounding disturbed zones. Our results demonstrate that the CNN model is fast and accurate to detect the horizontal locations of subsurface anomalies, while the accuracy of vertical locations depends on the estimation of P-wave velocity. The intelligent method has the potential to identify hidden risks at early stages and to mitigate subsequent geologic hazards.

本研究旨在开发一种探测地下异常的智能方法，以预测和降低地质风险。我们利用 6 个野外案例（规则管道和不规则空洞）的地震数据训练了一个卷积神经网络（CNN）模型，并利用滑动时间窗技术增强了数据集，还利用另外两个野外案例对 CNN 模型进行了测试。我们得出了作为异常存在指标的概率分布，并验证了分别与地下开口和周围扰动区相对应的高值和低值概率分布。我们发现，地下异常的特征决定了有效的地震特征，并影响 CNN 模型的性能。最后，我们应用 CNN 模型研究了一个圆形钻孔隧道及其周围的扰动区。结果表明，CNN 模型能够快速、准确地探测到地下异常的水平位置，而垂直位置的准确性则取决于对 P 波速度的估计。该智能方法具有在早期阶段识别隐患并减轻后续地质灾害的潜力。

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引用次数: 0

Numerical analysis of relative density effects on shallow TBM tunnel excavation: Ground behavior and principal strains at surface in greenfield conditions 相对密度效应对浅层 TBM 隧道挖掘的数值分析：绿地条件下的地表行为和主应变

IF 6.7 1区工程技术 Q1 CONSTRUCTION & BUILDING TECHNOLOGY

Tunnelling and Underground Space Technology

Pub Date : 2024-10-04 DOI: 10.1016/j.tust.2024.106104

Tunnel construction in urban areas may result in ground deformations that pose a risk to existing buildings and infrastructure; thus, accurate prediction of these induced ground deformations during the design phase is crucial. The paper focuses on the effects of sandy soil relative density on the ground deformations induced by tunnels excavated with Tunnel Boring Machines (TBMs). The study utilizes the Finite Element Method (FEM) and the NorSand model to simulate the behavior of a sandy ground. The validity of the FEM modeling approach is established by comparing predictions with results from six centrifuge tunnel tests from the literature. The centrifuge tests were performed on sand at different relative densities, tunnel diameters, and tunnel depths. The parameters for the NorSand model were determined based on laboratory tests. Only the state parameter was modified to achieve the desired relative density in the numerical simulations. The effects of relative density observed in centrifuge tests (Franza et al., 2019) have been numerically reproduced with no further adjustments of the model parameters. The rich outputs from the numerical models enabled an in-depth investigation of tunnel behavior, yielding new insights into how tunnels respond under varying relative densities, depths, and diameters. A comprehensive analysis of the induced ground deformations caused by shallow tunnels in sandy ground and the potential to damage buildings is included.

在城市地区修建隧道可能会导致地面变形，从而对现有建筑物和基础设施构成风险；因此，在设计阶段准确预测这些诱发的地面变形至关重要。本文重点研究了砂土相对密度对使用隧道掘进机（TBM）挖掘隧道所引起的地面变形的影响。研究利用有限元法（FEM）和 NorSand 模型模拟砂土的行为。通过将有限元建模方法的预测结果与文献中的六项离心隧道测试结果进行比较，确定了有限元建模方法的有效性。离心机试验是在不同相对密度、隧道直径和隧道深度的沙地上进行的。NorSand 模型的参数是根据实验室试验确定的。在数值模拟中，只修改了状态参数，以达到所需的相对密度。在离心机试验中观察到的相对密度效应（Franza 等人，2019 年）在数值模拟中得到了再现，无需进一步调整模型参数。数值模型的丰富输出有助于深入研究隧道行为，对隧道在不同相对密度、深度和直径条件下的反应有了新的认识。其中包括对砂质地层中浅层隧道引起的诱导地面变形及其对建筑物的潜在破坏的全面分析。

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引用次数: 0