Computers and Geotechnics最新文献_第5页

Ground-boundary scatter method for wavefield analysis of layered sites with single-faced arbitrarily stepped topographies 用于分析具有单面任意阶梯地形的层状场地波场的地界散射法

IF 5.3 1区工程技术 Q1 COMPUTER SCIENCE, INTERDISCIPLINARY APPLICATIONS

Computers and Geotechnics

Pub Date : 2024-10-30 DOI: 10.1016/j.compgeo.2024.106858

Zhewen Hu , Jianbo Li , Gao Lin , Shukai Ya

This study proposes a ground-boundary scatter method for calculating wavefields in layered sites with stepped topographies. The total wavefield is decomposed into the free field of the flat site and the reflected wavefield from the ground. The wave-reflection equivalent forces are calculated through a dynamic analysis of the ground-boundary substructure intercepted from a full-domain site model. In the scattering analysis, a scaling-line-based scaled boundary finite-element method in the time domain is developed for the high-accuracy simulations of semi-infinity in an asymmetric layered half-space. A domain reduction method based on accurate wavefield solutions is used to analyze the soil–structure interaction. The proposed method makes complex topography-dependent wavefield calculations more flexible and practical, thus overcoming the limitations of traditional methods for seismic input. It can be used for localized arbitrarily shaped stepped topographies based on near-field finite-element models, thereby satisfying engineering requirements. The detailed implementation steps are described. For validation, numerical examples of wave propagation are for in homogeneous and layered stepped half-space containing valleys and irregular stepped terrains under different plane-wave incidence directions. The engineering applicability of this method is benchmarked through the seismic analyses of a nuclear structure built on different single-faced stepped-topography sites, revealing its potential adverse effects on structural response.

本研究提出了一种地面边界散射法，用于计算具有阶梯状地形的层状场地的波场。总波场分解为平坦场地的自由场和来自地面的反射波场。波反射等效应力是通过对从全域场地模型中截取的地面边界子结构进行动态分析计算得出的。在散射分析中，开发了一种基于缩放线的时域缩放边界有限元方法，用于非对称分层半空间中半无限的高精度模拟。基于精确波场解的域缩减方法用于分析土壤-结构相互作用。所提出的方法使复杂的与地形相关的波场计算更加灵活实用，从而克服了传统地震输入方法的局限性。它可用于基于近场有限元模型的局部任意形状的阶梯状地形，从而满足工程要求。本文介绍了详细的实施步骤。为了验证其有效性，在不同平面波入射方向下，对包含山谷和不规则阶梯地形的均质和分层阶梯半空间进行了波传播数值示例。通过对建在不同单面阶梯状地形上的核结构进行地震分析，揭示了该方法对结构响应的潜在不利影响，从而确定了该方法在工程上的适用性。

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引用次数: 0

An insight into the effect of gas on pore clogging using a resolved CFD-DEM coupling model 利用解析的 CFD-DEM 耦合模型深入了解气体对孔隙堵塞的影响

IF 5.3 1区工程技术 Q1 COMPUTER SCIENCE, INTERDISCIPLINARY APPLICATIONS

Computers and Geotechnics

Pub Date : 2024-10-30 DOI: 10.1016/j.compgeo.2024.106866

Tuo Wang , Zhenming Shi , Ming Peng , Mengli Li

Pore clogging phenomena are commonly encountered in porous media and have been extensively investigated. However, with the increasing prominence of fields like hydrate extraction and carbon dioxide (CO₂) sequestration, which involve gas–liquid two-phase flow, the effect of gas on pore clogging remains largely unexplored. This study employed a coupled resolved computational fluid dynamics and discrete element method (CFD-DEM) in conjunction with the volume of fluid (VOF) method to simulate gas–liquid two-phase flow. In addition, scanned real particles and a truncated-cone pore are employed to simulate pore clogging process under fluid flow. The results indicate that the presence of gas intensifies the turbulence within the fluid field. Additionally, the interaction among gas, fluid, and particles increases the variability of the drag forces acting on the particles. These two factors lead to a decrease in particle pile stability and reduce the possibility of pore clogging. Moreover, the parameters study shows that with the increase of gas fraction, the fluctuation of particle drag force increases and the velocity of particles passing through pore increases. With the increase of constriction diameter, the velocity of particles passing through pore is accelerated, and the influence of gas is reduced.

孔隙堵塞现象是多孔介质中常见的现象，并已得到广泛研究。然而，随着涉及气液两相流的水合物提取和二氧化碳（CO2）封存等领域的日益突出，气体对孔隙堵塞的影响在很大程度上仍未得到探讨。本研究采用耦合解析计算流体动力学和离散元素法（CFD-DEM），结合流体体积法（VOF）模拟气液两相流。此外，还采用了扫描真实颗粒和截顶锥孔隙来模拟流体流动下的孔隙堵塞过程。结果表明，气体的存在加剧了流体场内的湍流。此外，气体、流体和颗粒之间的相互作用增加了作用在颗粒上的阻力的可变性。这两个因素导致颗粒堆稳定性下降，并降低了孔隙堵塞的可能性。此外，参数研究还表明，随着气体成分的增加，颗粒阻力的波动会增大，颗粒通过孔隙的速度也会增加。随着收缩直径的增大，颗粒通过孔隙的速度加快，气体的影响减小。

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引用次数: 0

A state surface model of unsaturated soil considering thermal and adsorptive effects 考虑热效应和吸附效应的非饱和土壤状态面模型

IF 5.3 1区工程技术 Q1 COMPUTER SCIENCE, INTERDISCIPLINARY APPLICATIONS

Computers and Geotechnics

Pub Date : 2024-10-30 DOI: 10.1016/j.compgeo.2024.106869

Shuang Liu , Yang Xiao , Yue Sun , Hao Cui , Guoliang Ma , Hanlong Liu

Constructing soil water retention curve model involving thermal, mechanical, and hydraulic hysteresis is essential for accurately predicting the retention characteristics of unsaturated soils under complicated conditions. A novel model depicting the retention of capillary and adsorbed water under the impact of thermal, mechanical, and hydraulic hysteresis, has been proposed. In which, the variations of void ratio-dependent capillary water have been captured based on the incremental relationship of a three-phase porous material and an empirical relationship. The impact of temperature has been described by incorporating two distinct non-isothermal functions for the matric suctions of capillary and adsorbed water. The disparity in soil water retention curves under drying and wetting branches is illustrated by leveraging the combined effect of contact angle and entrapped air. The comparisons between the predicted and measured results showed that the new model can reasonable predict the retention behaviors of unsaturated soils under different temperature, void ratio, and drying-wetting cycles.

要准确预测复杂条件下非饱和土壤的滞留特性，必须构建涉及热滞后、机械滞后和水力滞后的土壤水分滞留曲线模型。我们提出了一个新模型，描述了毛细管水和吸附水在热滞后、机械滞后和水力滞后影响下的滞留情况。其中，根据三相多孔材料的增量关系和经验关系，捕捉了毛细管水随空隙率的变化。通过对毛细管水和吸附水的母吸力采用两种不同的非等温函数来描述温度的影响。通过利用接触角和夹带空气的综合效应，说明了土壤在干燥和湿润分支下的保水曲线差异。预测结果与实测结果的比较表明，新模型可以合理预测非饱和土壤在不同温度、空隙率和干湿循环条件下的保水行为。

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引用次数: 0

Remote hydraulic fracturing at weak interfaces 弱界面远程水力压裂

IF 5.3 1区工程技术 Q1 COMPUTER SCIENCE, INTERDISCIPLINARY APPLICATIONS

Computers and Geotechnics

Pub Date : 2024-10-30 DOI: 10.1016/j.compgeo.2024.106830

Tao You , Keita Yoshioka

Many hydraulic fracturing experiments suggest that low-viscosity fluid tends to generate a complex fracture network, which may be beneficial for geo-energy production. However, the precise impacts of low-viscosity fluid on the fracture nucleation and propagation are unknown. This study focuses on the stress jump at weak interfaces (e.g., grain boundaries or natural fractures) caused by the contrast in Biot’s coefficient, which is prevalent in hard rocks, and how failure may develop. We found that fracture nucleation at weak interfaces becomes favorable under certain Biot’s coefficient contrast and fluid viscosity. Our numerical simulations of fluid injection through a borehole demonstrate that low-viscosity fluid injection can nucleate isolated fractures at remote interfaces without connecting to the main propagating fracture. These findings imply the necessity to consider Biot’s coefficient variations within a rock mass in applications such as hydraulic fracturing or induced seismicity, especially when a diffused pressure gradient persists due to the low-viscosity fluid.

许多水力压裂实验表明，低粘度流体倾向于生成复杂的裂缝网络，这可能有利于地质能源生产。然而，低粘度流体对裂缝成核和扩展的确切影响尚不清楚。本研究的重点是在坚硬岩石中普遍存在的由比奥特系数对比引起的弱界面（如晶界或天然裂缝）的应力跃迁，以及破坏是如何形成的。我们发现，在一定的比奥系数对比和流体粘度条件下，弱界面处的断裂成核变得有利。我们对通过井眼注入流体进行的数值模拟表明，低粘度流体注入可在偏远界面处形成孤立的断裂核，而不会与主传播断裂相连。这些发现表明，在水力压裂或诱发地震等应用中，尤其是在低粘度流体造成的扩散压力梯度持续存在的情况下，有必要考虑岩体内部的 Biot 系数变化。

引用次数: 0

Fully coupled large-strain radial consolidation analysis for dredged marine slurry treated by prefabricated vertical drain with vacuum and heat preloading 采用预制垂直排水器处理疏浚海水泥浆的全耦合大应变径向固结分析

IF 5.3 1区工程技术 Q1 COMPUTER SCIENCE, INTERDISCIPLINARY APPLICATIONS

Computers and Geotechnics

Pub Date : 2024-10-29 DOI: 10.1016/j.compgeo.2024.106852

Yang Liu , Peichen Wu , Penglin Li , Jian-Hua Yin , Jun-Jie Zheng

The use of prefabricated vertical drain (PVD) in conjunction with vacuum and heat preloading is an effective improvement approach for dredged marine slurry. Despite it being a typical large-strain thermal-hydro-mechanical (THM) problem, there is currently a lack of reliable large-strain analysis methods for this problem. This study therefore develops a large-strain radial consolidation model, considering a thermal elastoplastic constitutive model of soft clays, self-weight of dredged slurry, radial and vertical flows, nonlinear hydraulic conductivity, nonlinear compressibility during the consolidation process, heat conduction, and heat convection process. The modified alternative direction implicit (ADI) difference approach is used to solve the proposed model. The numerical algorithm is then verified by degraded verification with a well-established radial-large strain consolidation model. A laboratory experiment has been employed to show the effectiveness of the proposed model in predicting the consolidation behavior. A graphical user interface (GUI) has been programmed for potential users based on the proposed model and numerical algorithm. The results indicate that heat preloading improves the permeability of soil, resulting in a larger settlement of soil. Heat preloading serves as an effective method to enhance the efficiency of PVD.

使用预制垂直排水器 (PVD) 并结合真空和热预载是一种有效的疏浚海水泥浆改进方法。尽管这是一个典型的大应变热-水-机械（THM）问题，但目前缺乏可靠的大应变分析方法。因此，本研究开发了一种大应变径向固结模型，考虑了软粘土的热弹塑性构成模型、疏浚泥浆的自重、径向和垂直流、非线性水力传导、固结过程中的非线性可压缩性、热传导和热对流过程。该模型采用修正的替代方向隐式（ADI）差分法求解。然后，利用成熟的径向大应变固结模型对数值算法进行降级验证。实验室实验证明了所提模型在预测固结行为方面的有效性。根据所提出的模型和数值算法，为潜在用户设计了图形用户界面（GUI）。结果表明，热预载可改善土壤的渗透性，从而使土壤产生更大的沉降。热预载是提高 PVD 效率的有效方法。

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引用次数: 0

Torsional dynamic response of rigid footings and pile foundations for various end-conditions 各种端部条件下刚性基脚和桩基的扭转动态响应

IF 5.3 1区工程技术 Q1 COMPUTER SCIENCE, INTERDISCIPLINARY APPLICATIONS

Computers and Geotechnics

Pub Date : 2024-10-28 DOI: 10.1016/j.compgeo.2024.106857

Bipin K. Gupta

An analysis for torsional dynamic response of rigid footings and pile foundations with various end-conditions: half-space, soil stratum, and end-bearing is demonstrated. The interaction adjacent to footing/pile is simulated through the Vlasov-Leont′ev foundation model. Because of stress singularity at the pile/footing base, the end-conditions (half-space and soil stratum) at the foundation base are incorporated in the boundary conditions of the analysis through expressions in literature. The expressions are obtained from the torsional dynamic response of a rigid disk welded to the surface of the viscoelastic media. Several expressions, from various formulations, are employed, and the degree of accuracy of each expression is assessed through an extensive comparative study with rigorous and simplified solutions in the literature. The expression that is most accurate and captures the mechanics of the interaction problem in a half-space/soil stratum is extracted and proposed. The accuracy of the Vlasov-Leont′ev foundation model is also assessed for end-bearing pile foundations. For each end-condition, parametric studies are also performed for a wide range of frequencies, and pile-slenderness and stiffness ratios, and appropriate conclusions derived from the studies are reported. Comparisons with experimental results are shown to demonstrate the applicability of the analysis to geotechnical engineering practice.

对刚性基脚和桩基的扭转动力响应进行了分析，其端部条件各不相同：半空间、土层和端部承载。通过 Vlasov-Leont′ev 地基模型模拟了邻近基脚/桩的相互作用。由于桩基/基脚基底存在应力奇异性，因此通过文献中的表达式将基底的端部条件（半空间和土层）纳入分析的边界条件中。这些表达式是从焊接在粘弹性介质表面的刚性圆盘的扭转动态响应中获得的。通过与文献中的严格解法和简化解法进行广泛的比较研究，评估了每个表达式的准确程度。提取并提出了最准确、最能反映半空间/土层中相互作用力学问题的表达式。此外，还评估了 Vlasov-Leont′ev 地基模型对端承式桩基的准确性。对于每种端部条件，还针对各种频率、桩斜度和刚度比进行了参数研究，并报告了研究得出的适当结论。报告还显示了与实验结果的比较，以证明该分析适用于岩土工程实践。

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引用次数: 0

Polynomial response surface-informed neural network for implicit slope reliability analysis and uncertainty quantification 用于隐式边坡可靠性分析和不确定性量化的多项式响应面信息神经网络

IF 5.3 1区工程技术 Q1 COMPUTER SCIENCE, INTERDISCIPLINARY APPLICATIONS

Computers and Geotechnics

Pub Date : 2024-10-26 DOI: 10.1016/j.compgeo.2024.106832

Jian Ji , Xin Yin , Tong Zhang , Bin Tong , Shigui Du

In slope reliability analysis, surrogate models are usually designed to replace the computationally expensive performance functions. For slope reliability problems considering high dimensional simulation of soil spatial variability, the surrogate model must be constructed using sufficient sampling points in order to cover the high dimension domain of model parameters, potentially making its robustness sensitive to the sample size. This paper proposes a novel surrogate modelling framework, the PRS-informed NN (alternative to the physics-informed neural network, PINN), which integrates a polynomial response surface (PRS, representing a small-scale physical law indicator) with a neural network surrogate model (NN, representing a large-scale model performance) to enhance the modelling performance across various sample sizes and reduce uncertainty. Based on the Karhunen-Loeve expansion technique, the dimension of variables involved in random field discretization is firstly reduced, simplifying the computation for probability of slope failure (P_f). The PRS that plays a role of basic physical law of slope stability model, is integrated into the neural network by adjusting the training loss function. The feasibility of the proposed method is demonstrated through a synthetic slope model and a real-world slope case study. Results show that the proposed framework improves the accuracy of neural network surrogate models, especially with smaller sample sizes. At last, both aleatory and epistemic uncertainties in the surrogate modelling are quantified, followed by a detailed discussion of the confidence interval for the P_f estimation.

在边坡可靠性分析中，通常设计代用模型来替代计算成本高昂的性能函数。对于考虑土壤空间变异性高维模拟的边坡可靠性问题，必须使用足够多的采样点来构建代用模型，以覆盖模型参数的高维域，这可能会使其稳健性对采样大小非常敏感。本文提出了一种新的代用建模框架--PRS-informed NN（物理信息神经网络的替代方案，PINN），它将多项式响应面（PRS，代表小尺度物理规律指标）与神经网络代用模型（NN，代表大尺度模型性能）集成在一起，以提高不同样本量下的建模性能并降低不确定性。基于卡尔胡宁-洛夫扩展技术，首先降低了随机场离散化所涉及的变量维度，从而简化了边坡坍塌概率（Pf）的计算。通过调整训练损失函数，将作为边坡稳定性模型基本物理规律的 PRS 集成到神经网络中。通过合成斜坡模型和实际斜坡案例研究，证明了所提方法的可行性。结果表明，所提出的框架提高了神经网络代用模型的准确性，尤其是在样本量较小的情况下。最后，量化了代用模型中的不确定性和认识不确定性，并详细讨论了 Pf 估计的置信区间。

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引用次数: 0

Prediction of TBM cutter wear in heterogeneous ground under high ambient pressure 高环境压力下异质地层中隧道挖掘机铣刀磨损预测

IF 5.3 1区工程技术 Q1 COMPUTER SCIENCE, INTERDISCIPLINARY APPLICATIONS

Computers and Geotechnics

Pub Date : 2024-10-24 DOI: 10.1016/j.compgeo.2024.106837

Nan Zhang , Shui-Long Shen

To prevent tunnel face collapse in heterogeneous ground, the applied face pressure in the excavation chamber can be increased to stabilise the tunnel face, which may hinder cutter rotation during tunnel boring machine (TBM) tunnelling. This study proposes a TBM cutter wear prediction model that considers the impact of the variation in the cutter normal force on the cutterhead owing to the high applied face pressure and low penetration rate. First, the cutter motion mode in heterogeneous ground is investigated. The cutter is found to slide when cutting soft rock based on an analysis of the field data. The evolution process of the cutter wear morphology under heterogeneous ground conditions is summarised. A method for calculating the cutter normal force when the cutter slides on the tunnel face is proposed by referring to the cutting mechanism of the drag bits. The cutter hardness is measured on-site using a portable hardness tester. A semi-empirical model considering the variation in the cutter normal force on the cutterhead is proposed to predict the cutter wear in heterogeneous ground. Wear prediction is compared with other predictive models and field data for validation, and the discrepancies between the different models are discussed. The results show that the proposed model is effective for predicting TBM cutter wear under complex geological conditions.

为防止异质地层中的隧道工作面坍塌，可增加挖掘室中的工作面压力以稳定隧道工作面，但这可能会阻碍隧道掘进机（TBM）在隧道掘进过程中的铣挖机旋转。本研究提出了一种 TBM 刀盘磨损预测模型，该模型考虑了高施加工作面压力和低贯入率导致的刀盘法向力变化对刀盘的影响。首先，研究了铣挖机在异质地层中的运动模式。根据对现场数据的分析，发现铣挖机在铣挖软岩时会发生滑动。总结了异质地层条件下铣挖机磨损形态的演变过程。参照拖曳钻头的切割机制，提出了一种计算铣挖机在隧道面上滑动时铣挖机法向力的方法。使用便携式硬度计现场测量了铣挖机的硬度。考虑到刀盘上刀盘法向力的变化，提出了一个半经验模型来预测异质地层中的刀盘磨损。磨损预测与其他预测模型和现场数据进行了比较验证，并讨论了不同模型之间的差异。结果表明，所提出的模型可有效预测复杂地质条件下的 TBM 刀盘磨损。

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引用次数: 0

GeoLLM: A specialized large language model framework for intelligent geotechnical design GeoLLM：用于智能岩土工程设计的专用大型语言模型框架

IF 5.3 1区工程技术 Q1 COMPUTER SCIENCE, INTERDISCIPLINARY APPLICATIONS

Computers and Geotechnics

Pub Date : 2024-10-24 DOI: 10.1016/j.compgeo.2024.106849

Hao-Ruo Xu , Ning Zhang , Zhen-Yu Yin , Pierre Guy Atangana Njock

Large language models (LLMs) have achieved remarkable success in various industrial and research fields, enhancing work efficiency by assisting machines in comprehending human language. In geotechnical design where extensive repetitive cross-checking of design codes consumes considerable time and labour, the utilization of LLMs to enhance design procedures has not been explored before. The challenge is to ensure that LLMs accurately comprehend professional geotechnical information from text and execute mathematical calculations correctly. This study makes the first attempt at developing a specialized LLM framework, GeoLLM, integrated with an innovative prompt engineering strategy to extract professional information from text and enable accurate mathematical calculations. GeoLLM is applied to the design of single piles involving bearing capacity and settlement calculations. The results reveal that GeoLLM exhibits excellent performance in single pile cases. Additionally, compared with LLMs of varying architectures and sizes, commercial LLMs with over 100 billion parameters presented outstanding comprehensive capacities, while those with 1.8 ∼ 72 billion parameters degraded relatively. These findings indicate the promising capacity of GeoLLM to address professional tasks in geotechnical design.

大语言模型（LLMs）通过辅助机器理解人类语言，提高了工作效率，在各个工业和研究领域都取得了显著的成就。在岩土工程设计中，设计规范的大量重复性交叉检查耗费了大量的时间和人力，而利用 LLMs 来改进设计程序则是前所未有的。如何确保 LLM 能够准确理解文本中的专业岩土工程信息并正确执行数学计算是一项挑战。本研究首次尝试开发专门的 LLM 框架--GeoLLM，并将其与创新的提示工程策略相结合，以从文本中提取专业信息并实现准确的数学计算。GeoLLM 被应用于涉及承载力和沉降计算的单桩设计。结果表明，GeoLLM 在单桩案例中表现出卓越的性能。此外，与不同结构和规模的 LLM 相比，拥有超过 1000 亿个参数的商用 LLM 具有出色的综合能力，而拥有 180 ∼ 720 亿个参数的 LLM 则相对较差。这些发现表明，GeoLLM 在解决岩土工程设计中的专业任务方面具有广阔的前景。

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引用次数: 0

A new three-dimensional strength criterion considering the transverse isotropy based on the α-Spatial Mobilized Plane 基于 α 空间移动平面的考虑横向各向同性的新三维强度准则

IF 5.3 1区工程技术 Q1 COMPUTER SCIENCE, INTERDISCIPLINARY APPLICATIONS

Computers and Geotechnics

Pub Date : 2024-10-24 DOI: 10.1016/j.compgeo.2024.106853

Kun Wang, Daofei Tang, Tian Fang, Changhong Wang

Natural geotechnical materials are affected by sedimentation and exhibit significant anisotropy. To study the transverse isotropy characteristics of soil, the influence of intermediate principal stress and loading direction must be considered. Currently, research on transverse isotropy primarily focuses on the modified stress space, which is cumbersome to apply in multi-yield surface constitutive models. To describe the three-dimensional mechanical properties of geomaterials in real stress space, the α-Spatial Mobilized Plane strength criterion is introduced. Then, combined with the structure tensor, the transverse isotropic three-dimensional strength criterion can account for the effect of the loading angle. Finally, the three-dimensional strengths of Fukakusa clay, unsaturated SP-SC soils, uncemented Monterey sands, Yamaguchi marble, San Francisco Bay mud, Toyoura sand, and Santa Monica Beach sand are predicted on the π-plane. The results show that the

α_{m}^{n} - S M P

criterion, in the context of transverse isotropy, can describe the three-dimensional mechanical properties reasonably, and it can provide an accurate strength criterion for geotechnical engineering practice.

天然岩土材料受沉积作用影响，表现出明显的各向异性。要研究土的横向各向异性特征，必须考虑中间主应力和加载方向的影响。目前，有关横向各向异性的研究主要集中在修正应力空间，而修正应力空间在多屈服面构成模型中的应用比较麻烦。为了在真实应力空间中描述土工材料的三维力学性能，引入了 α 空间移动平面强度准则。然后，结合结构张量，横向各向同性三维强度准则可以考虑加载角度的影响。最后，预测了深草粘土、非饱和 SP-SC 土、未加固蒙特雷砂、山口大理石、旧金山湾泥、丰浦砂和圣莫尼卡海滩砂在π平面上的三维强度。结果表明，在横向各向同性的情况下，αmn-SMP 准则能够合理地描述三维力学性能，并能为岩土工程实践提供准确的强度准则。

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引用次数: 0