Engineering Geology最新文献_第5页

Cultural activity and impact of extreme weather events revealed by ambient seismic noise and perspective on quick clay failure monitoring in Oslo, Norway

IF 6.9 1区工程技术 Q1 ENGINEERING, GEOLOGICAL

Engineering Geology

Pub Date : 2025-02-01 DOI: 10.1016/j.enggeo.2025.107936

Charlotte Bruland , Anna Maria Dichiarante , Andreas Köhler , Volker Oye , Ivan Van Bever , Eric Larose

The study of urban seismic noise offers various approaches to monitor cities, from source identification to structural investigations. We demonstrate its potential to monitor cultural activity and quick clay failure in Oslo, Norway using low-cost seismic sensors. We identify train passages, a rock concert, construction blasts, local earthquakes and a meteor. To retrieve seismic velocity variations in the near subsurface, we apply seismic interferometry to three years of urban noise (1–4 Hz) recorded at four sensors, two in a quick clay risk area. Despite urban noise variability, we obtain stable noise correlation functions using 1-day-stacks. The extracted velocity variations reveal changes in the ground due to freezing and thawing as well as due to pore pressure variations related to snowmelt and rainfall. Along with anti-correlation of velocity variations and pore pressure, we observe hysteresis associated to the soil’s water retention under different moisture conditions, which could provide insights into potential landslide hazard. A sharp velocity drop accompanying the heavy rainfall associated with an extreme weather event is observed. All these observations give us insights to what subsurface changes can be resolved and expected over longer time periods, which will allow us to identify unusual and permanent changes, e.g., related to quick clay. Theoretical dispersion curve analysis shows that lowering the velocity in a section of the sedimentary layer containing quick clay reduces surface wave velocities within the frequency range of interest. These results suggest that measuring velocity variations at our study site has the potential to detect quick clay instabilities.

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引用次数: 0

Numerical study on the stiffening properties of scour protection around monopiles for Offshore Wind Turbines 海上风力机单桩防冲加固性能数值研究

IF 6.9 1区工程技术 Q1 ENGINEERING, GEOLOGICAL

Engineering Geology

Pub Date : 2025-02-01 DOI: 10.1016/j.enggeo.2024.107835

Carlos Menéndez-Vicente , Susana López-Querol , John M. Harris , Nicholas S. Tavouktsoglou

An active marine seabed causing scour around monopile foundations has to be addressed as a geological hazard. These structures are often protected with rock armour to prevent foundation failure. However, scour protection also increases the confining pressure and embedment length, providing additional stiffness to the soil–pile system. This study focuses on the stiffening effect of scour protection to optimise foundation design. A parametric analysis of the dimensions and materials of scour protection is carried out with more than 100 simulations to assess the stiffening effect of scour protection. Therefore, small-diameter and large-diameter monopiles are investigated. Numerical analysis with the Finite Element method is conducted to estimate the natural frequencies and the static capacity through moment and lateral load (

M - H

) curves and the Load Utilisation method. These methods, which are new to the study of scour protection, are proposed for the quantification and assessment of scour protection in foundation design. The results show that rock fill restores the initial foundation conditions independently of the pile dimensions. While for small-diameter monopiles, scour protection fulfils its double purpose of preventing scour and providing stiffness to the foundation, for large-diameter monopiles the contribution to the stiffness is limited and should only be considered for heavy rock armour and significant scour protection heights. The parametric analysis indicates that a thicker and heavier scour protection increases the static capacity by 10%, whereas the width or a densification through sand accretion have negligible effects (

<

1%). The

M - H

curves and the Load Utilisation method have shown to be effective in assessing the static capacity of monopiles supporting Offshore Wind Turbines.

活跃的海洋海床在单桩基础周围造成冲刷，必须作为地质灾害来处理。这些结构通常有岩甲保护，以防止基础破坏。然而，防冲刷也增加了围压和嵌入长度，为土桩体系提供了额外的刚度。本文主要研究冲刷防护的加劲作用，以优化基础设计。对冲蚀防护的尺寸和材料进行了参数化分析，并进行了100多次仿真，以评估冲蚀防护的加筋效果。因此，研究了小直径和大直径单桩。通过弯矩和横向荷载（M - H）曲线以及荷载利用率法，对其固有频率和静承载力进行了有限元数值分析。这些方法是对基础设计中冲刷防护的量化和评价提出的新方法。结果表明，填石对初始地基条件的恢复与桩身尺寸无关。对于小直径单桩，防冲既能起到防止冲刷的作用，又能起到为基础提供刚度的双重作用，而对于大直径单桩，其对刚度的贡献是有限的，只有在岩甲较重、防冲高度较大的情况下才应考虑防冲作用。参数分析表明，较厚和较重的冲刷防护可使静容量增加10%，而宽度或增砂密度对静容量的影响可忽略不计（<1%）。M - H曲线和荷载利用方法在评估支撑海上风力涡轮机的单桩静容量方面是有效的。

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引用次数: 0

3D high-density ambient noise imaging of the Nankou-Sunhe buried active fault in Beijing 北京南口-孙河隐伏活动断裂三维高密度环境噪声成像

IF 6.9 1区工程技术 Q1 ENGINEERING, GEOLOGICAL

Engineering Geology

Pub Date : 2025-02-01 DOI: 10.1016/j.enggeo.2024.107862

Xu Liu , Ketong Hu , Rongyi Qian , Shuai Zhao , Jun Zhang , Jianyu Ling , Zhenning Ma , Zhiyong Wu , Yinhu Huang , Yongqi Meng , Zhanfei Li , Dongya Zhang

The Nankou-Sunhe fault (NSF) is a vital buried active fault within the Beijing Plain. Investigating the detailed structure of the NSF and the sedimentary structures on both sides is pivotal for urban engineering projects to mitigate geological hazards. Three-dimensional (3D) seismic exploration can provide comprehensive and precise information about subsurface structures, aiding in the identification and characterisation of the spatial geometry, extensional direction, and features of sedimentary structures on both sides of the fault. In this study, we conducted a 3D high-density ambient noise seismic survey covering approximately 40 km² around the NSF. Utilising the Multichannel Analysis of Passive Surface waves (MAPS), we obtained fundamental mode Rayleigh wave phase velocity diagrams in the 0.5–4 Hz range, subsequently inverting them to reveal a 3D shear (S)-wave velocity model extending to a depth of 1 km. The model shows lower velocities in the southwestern region, with shallow S-wave velocities of approximately 400–600 m/s and deep-seated velocities ranging from 1800 to 2000 m/s. The northeastern region is characterised by higher velocities, with shallow S-wave velocities of approximately 900–1200 m/s and deeper velocities reaching 3000–3400 m/s. The NSF is a high angle (50°-70°) normal fault striking northeast and dipping towards the southwest; the dip angle exhibits local variation. An S-wave velocity of 1 km/s was used to estimate sediment thickness on both sides of the fault. The MaChikou Sag (MCKS) on the southwest side of the NSF is approximately 400–600 m thick, while the northeastern JingXi High (JXH) is less than 200 m thick. The NSF was positively correlated with the bedrock surface (1 km/s isovelocity). Moreover, this study ascertained that by employing MAPS with a 200 m station spacing within a complex and noisy urban environment, one can extract accurate fundamental-mode Rayleigh waves, allowing for the subsequent construction of a 3D high-resolution S-wave velocity model.

南口-孙河断裂是北京平原内一条重要的隐伏活动断裂。研究NSF的详细构造及其两侧的沉积构造是城市工程项目减轻地质灾害的关键。三维地震勘探可以提供全面而精确的地下构造信息，有助于识别和表征断层两侧的空间几何形状、伸展方向和沉积构造特征。在这项研究中，我们对NSF周围约40 km2的区域进行了三维高密度环境噪声地震调查。利用被动表面波多通道分析（MAPS），我们获得了0.5-4 Hz范围内的基本模态瑞利波相速度图，随后将其反演，得到了延伸至1 km深度的三维剪切(S)波速度模型。模型显示西南地区速度较低，浅层横波速度约为400 ~ 600 m/s，深层横波速度约为1800 ~ 2000 m/s。东北地区速度较大，浅层横波速度约为900 - 1200m /s，深层横波速度约为3000 - 3400m /s。NSF为一条高角度（50°~ 70°）正断层，走向东北，向西南倾斜；倾角呈现局部变化。采用1 km/s的横波速度估算断层两侧的沉积物厚度。NSF西南侧的马池口凹陷（MCKS）厚度约为400 ~ 600 m，而东北侧的靖西高压（JXH）厚度不足200 m。NSF与基岩面（1 km/s等速度）呈正相关。此外，本研究确定，在复杂和嘈杂的城市环境中，使用200 m站距的MAPS可以提取准确的基模瑞利波，从而允许随后构建3D高分辨率横波速度模型。

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引用次数: 0

Characterization of directionality influence on non-Darcian flow in single rock fractures

IF 6.9 1区工程技术 Q1 ENGINEERING, GEOLOGICAL

Engineering Geology

Pub Date : 2025-02-01 DOI: 10.1016/j.enggeo.2025.107947

Zihao Sun , Liangchao Zou , Jia-Qing Zhou , Liangqing Wang , Yue Zhu , Xunwan Yao , Rui Ke

Significant differences in non-Darcian flow between different directions (i.e., forward and reverse flow directions) exist in rock fractures, and understanding of these differences holds crucial implications for evaluating and characterizing flow within fractured rocks. This study proposes a directional aperture parameter to quantitatively characterize the differences in flow between different directions. Firstly, a directional aperture parameter capable of quantitatively distinguishing geometric information of fractures in different directions is proposed. Then, 900 sets of linear and nonlinear flow numerical experiments based on 90 rough fractures are conducted. The results reveal that the differences between forward and reverse flow are shown in the nonlinear flow regime, with equal viscous permeability but significant differences in inertial permeability between the two flow directions. The main reason for the differences lies in the variations of aperture along the two flow directions. A dual-parameter model characterizing the inertial permeability is established by using the directional aperture parameter based on the numerical experimental data from the 90 rough fractures. The critical condition where the significant differences between the forward and reverse flow starting to appear are identified. The quantitative characterization of differences in three-dimensional rough fractures between different directional flows is discussed. The findings from this study could be helpful in advancing our understanding of fluid flow behaviors in natural rock fractures.

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引用次数: 0

Exploring the relationship between seismic noise signals and modeled river flow data: A case study from Sicily, Italy 探讨地震噪声信号与模拟河流流量数据之间的关系：以意大利西西里岛为例

IF 6.9 1区工程技术 Q1 ENGINEERING, GEOLOGICAL

Engineering Geology

Pub Date : 2025-02-01 DOI: 10.1016/j.enggeo.2024.107872

Alfio Marco Borzì , Federico Castiglione , Mario Valerio Gangemi , Andrea Cannata , Luca Cavallaro , Enrico Foti , Rosaria Ester Musumeci , Francesco Panzera

In this work, we analyze and integrate the seismic data recorded by one seismic station installed close to the Cimia River (Gela, Sicily), the rainfall data recorded by the meteorological stations installed within the Gela hydrological basin, and the flow data estimated using a rainfall-runoff model. We take into account two meteorological events characterized by different features in terms of duration, total rainfall, rainfall intensity, and flow rate: an impulsive short-term thunderstorm that occurred on 13th October 2022, and a long-duration perturbation that took place in February 2023 during the quasi-Medicane Helios. In particular, we explore the relationships between seismic noise (in terms of spectral content, root mean square amplitude time series, and polarization features) and meteorological and hydrological parameters (specifically, rain rate, total rainfall, and net rainfall within the basin, as well as the flow rate at a relevant cross-section along the river). The results show that only the long-duration event (i.e., Helios) leaves a mark on the seismic signals and that the time lag obtained between the root mean square amplitude and rain rate time series matches with the catchment's concentration time. These findings show a clear correlation between seismic noise and hydrological parameters, allowing us to retrieve information about flood events using seismic data when traditional river discharge data are unavailable.

在这项工作中，我们分析和整合了靠近西西里岛的西米亚河（Gela，西西里岛）的一个地震台站记录的地震数据、安装在Gela水文流域内的气象站记录的降雨数据以及使用降雨-径流模型估计的流量数据。我们考虑了两个在持续时间、总降雨量、降雨强度和流量方面具有不同特征的气象事件：一个是发生在2022年10月13日的脉冲短期雷暴，另一个是发生在2023年2月的准美第奇太阳日期间的长时间扰动。特别是，我们探索了地震噪声（频谱含量、均方根振幅时间序列和极化特征）与气象水文参数（流域内降雨率、总降雨量、净降雨量以及沿河相关断面的流量）之间的关系。结果表明，只有持续时间较长的事件（如太阳神）才会在地震信号上留下痕迹，而均方根振幅和雨率时间序列之间的滞后时间与集水区浓度时间吻合。这些发现表明地震噪声与水文参数之间存在明显的相关性，使我们能够在无法获得传统河流流量数据的情况下，利用地震数据检索洪水事件的信息。

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引用次数: 0

Numerical investigation on the response of ground-reinforced embankments under repeated impact 反复冲击作用下加筋土路堤响应的数值研究

IF 6.9 1区工程技术 Q1 ENGINEERING, GEOLOGICAL

Engineering Geology

Pub Date : 2025-02-01 DOI: 10.1016/j.enggeo.2024.107875

Xin Li , Zhiwei Gao , Liang Lu

Ground-reinforced embankment (GRE) is an effective and environmentally friendly technique of rockfall intervention. These earth structures are built with layers of compacted soil alternated with geotextiles, geogrills, metallic wire stripes or nets. GREs are designed to sustain repeated rock impact during their service life, but there is very little experimental or numerical research on the GRE response under such impact conditions. A comprehensive numerical investigation of GRE response under repeated rock impact is carried out. The GRE is built with several layers of sand wrapped by geosynthetics. An advanced elastoplastic constitutive model for sand is adopted. For the GREs built with dense and loose sand, most of the impact energy is dissipated by plastic deformation in the soil. Sand density has a dominant influence on the deformation and failure mechanism of GREs. During repeated impacts, elements near the impact location fail with increasing mean effective stress and Mises stress in dense sand. However, soil elements reach failure as the mean effective stress decreases and the Mises stress increases. There is much less deformation accumulation in GRE when the void ratio is lower as the soil has higher stiffness and shear strength. After multiple impacts, shear bands form in loose sand but strain localisation mainly occurs at the impact point for dense sand.

地基加筋路堤是一种有效的、环保的岩崩治理技术。这些土结构是用夯实的土壤层、土工织物、土工格栅、金属丝条或网交替建造的。GRE的设计初衷是为了在其使用寿命期间承受岩石的反复冲击，但对这种冲击条件下GRE响应的实验或数值研究很少。对岩石反复冲击作用下的GRE响应进行了全面的数值研究。GRE是由几层由土工合成材料包裹的沙子建造的。采用一种先进的砂土弹塑性本构模型。对于用致密松散砂土建造的减振器，大部分冲击能通过土体的塑性变形来耗散。砂石密度对砂石的变形破坏机制有主导影响。在重复冲击过程中，靠近冲击位置的构件随着平均有效应力和密砂中米塞斯应力的增大而失效。然而，随着平均有效应力的减小和米塞斯应力的增大，土元达到破坏状态。由于土体刚度和抗剪强度较高，孔隙率越低，土体的变形积累越少。松散砂土经过多次冲击后会形成剪切带，而致密砂土主要在冲击点处出现应变局部化。

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引用次数: 0

Towards automatic delineation of landslide source and runout 滑坡源与跳动的自动圈定

IF 6.9 1区工程技术 Q1 ENGINEERING, GEOLOGICAL

Engineering Geology

Pub Date : 2025-02-01 DOI: 10.1016/j.enggeo.2024.107866

Kushanav Bhuyan , Kamal Rana , Ugur Ozturk , Lorenzo Nava , Ascanio Rosi , Sansar Raj Meena , Xuanmei Fan , Mario Floris , Cees van Westen , Filippo Catani

Mapping landslide-depleted source areas is pivotal for refining predictive models and volume estimations, yet these critical regions are often conflated with landslide runouts, leading to sub-optimal assessments. The source (or scarp) areas are typically the regions where the actual failure occurs, providing crucial information on the initiation mechanisms and the nature of landslide propagation. Catering to this objective, we built a method based on a landslide’s topology and morphological information to delineate the source and runout margins. We develop and test this method in geomorphologically distinct regions such as Dominica, Turkey, Italy, Nepal, and Japan (Niigata) to showcase the model’s robust adaptive capacity. The model can demarcate the source and runout zones from landslide planforms found in inventories with accuracy deviations under 15%–20%. While distinguishing landslide source and runout areas, the model also considers triggering information and movement types. We also deploy the model in Chile, Japan (Hokkaido), Colombia, Papua New Guinea, and China. In these new regions, we found the mean area of the scarp to be consistently under 30% of the total landslide area. We additionally showcased the application of our model to the area–volume scaling of the coseismic landslides triggered by the 2018 Hokkaido Eastern Iburi Earthquake (

M_{W}

6.6) in Japan. Our analysis revealed that area–volume fitting using the landslide source areas instead of the total landslide planforms or polygons improves the linear fit from R

^{2}

=0.49 to R

^{2}

=0.81. Our work could improve diverse landslide analysis, such as hazard and runout models, and facilitate a deeper understanding of landslide behaviour.

绘制滑坡枯竭源区的地图对于完善预测模型和体积估算至关重要，但这些关键区域往往与滑坡爆发区相混淆，导致评估结果不理想。震源（或陡坡）区域通常是实际发生破坏的区域，提供了关于滑坡发生机制和传播性质的关键信息。为了实现这一目标，我们建立了一种基于滑坡的拓扑和形态信息的方法来划定源和跳动边界。我们在地貌不同的地区开发并测试了这种方法，如多米尼加、土耳其、意大利、尼泊尔和日本（新潟），以展示该模型强大的适应能力。该模型能较好地从库存中发现的滑坡台地中划分出震源区和跳动区，精度偏差在15% ~ 20%之间。该模型在区分滑坡源区和跳动区的同时，还考虑了触发信息和运动类型。我们还在智利、日本（北海道）、哥伦比亚、巴布亚新几内亚和中国部署了该模型。在这些新区域，我们发现陡坡的平均面积一直低于滑坡总面积的30%。此外，我们还展示了我们的模型在2018年日本北海道东伊武里地震（MW 6.6）引发的同震滑坡的面积-体积缩放中的应用。我们的分析表明，使用滑坡源区而不是总滑坡平台或多边形的面积-体积拟合将线性拟合从R2=0.49提高到R2=0.81。我们的工作可以改善各种滑坡分析，如危险和跳动模型，并促进对滑坡行为的更深入理解。

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引用次数: 0

A unified characterization of small-strain shear modulus of sands under triaxial compression stress states 三轴压应力状态下砂土小应变剪切模量的统一表征

IF 6.9 1区工程技术 Q1 ENGINEERING, GEOLOGICAL

Engineering Geology

Pub Date : 2025-02-01 DOI: 10.1016/j.enggeo.2024.107863

Yutang Chen , Jun Yang

In slopes and embankments, soil elements are often anisotropically loaded and the sustained stress ratio SR may vary a lot. The understanding of the influence of SR on the small-strain shear modulus G₀ of sands prior to failure is a practical concern that remains inadequately understood in the existing literature. This study aims to address this knowledge gap through a meticulously designed experimental program. The testing program encompasses three quartz sands with differing particle shapes and a diverse set of principal stress ratios produced via drained triaxial compression. By employing bender elements embedded within the apparatus, elastic shear waves are generated, enabling the measurement of G₀ from isotropic stress states to anisotropic stress states. A careful evaluation and comparison of existing anisotropic G₀ models in the literature is also conducted, and the potential limitations when subjected to elevated SR levels are noted. A new, unified model is proposed to effectively characterize G₀ of different sands subjected to a wide range of triaxial compression states and it is validated using literature data.

在边坡和路堤中，土元经常受到各向异性荷载，持续应力比SR可能变化很大。SR对破坏前砂的小应变剪切模量G0的影响的理解是一个实际问题，但在现有文献中仍然没有得到充分的理解。本研究旨在通过精心设计的实验方案来解决这一知识差距。测试程序包括三种不同颗粒形状的石英砂，以及通过排水三轴压缩产生的不同主应力比。通过在仪器中嵌入弯曲元件，产生弹性剪切波，使G0从各向同性应力状态到各向异性应力状态的测量成为可能。对文献中现有的各向异性G0模型进行了仔细的评估和比较，并指出了在SR水平升高时的潜在局限性。提出了一种新的统一模型，可以有效地表征不同砂在大范围三轴压缩状态下的G0，并利用文献数据对其进行了验证。

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引用次数: 0

Water reactive polyurethane grouting for deep vadose zone contaminant immobilization

IF 6.9 1区工程技术 Q1 ENGINEERING, GEOLOGICAL

Engineering Geology

Pub Date : 2025-01-29 DOI: 10.1016/j.enggeo.2025.107945

Jinhu Song , Drew W. Johnson , Jie Huang , Sarah Saslow

Contaminants in the deep vadose zone (DVZ) pose a long-term threat to groundwater, human health, and the environment. Polyurethane grouting is a type of chemical grouting that is potentially advantageous in immobilizing contaminants in DVZs. Polyurethane resin has low viscosity that makes it feasible to penetrate and fill the pore space between fine particles. In this study a series of laboratory pressure grouting and leaching tests were conducted to simulate and assess the effectiveness of polyurethane grouting for immobilizing contaminants in DVZs. Soil with fine particles was prepared with ¹²⁷I (as iodide) that served as a non-radioactive surrogate for radioactive ¹²⁹I. After grouting and curing, leaching tests were used to measure and compare contaminant diffusivity and leachability index values. Additionally, changes in porosity and saturated hydraulic conductivity of grouted soil were measured. X-Ray Computer Tomography (XCT) results showed that the cured polyurethane was distributed nearly homogeneously and approximately half of the voids were filled with cured polyurethane. Grouting reduced the saturated hydraulic conductivity of soil by 37 %. The effective diffusivity decreased by more than 80 % as compared with the ungrouted soil. The leachability index of the grouted soil was 6.5; meeting the criteria established by the U.S. Nuclear Regulatory Commission (NRC) standard. The results obtained in this study provide a valuable assessment of polyurethane grouting for iodide immobilization in the DVZ and indicate this approach may be a viable method for contaminant remediation in DVZ soils.

{"title":"Water reactive polyurethane grouting for deep vadose zone contaminant immobilization","authors":"Jinhu Song , Drew W. Johnson , Jie Huang , Sarah Saslow","doi":"10.1016/j.enggeo.2025.107945","DOIUrl":"10.1016/j.enggeo.2025.107945","url":null,"abstract":"<div><div>Contaminants in the deep vadose zone (DVZ) pose a long-term threat to groundwater, human health, and the environment. Polyurethane grouting is a type of chemical grouting that is potentially advantageous in immobilizing contaminants in DVZs. Polyurethane resin has low viscosity that makes it feasible to penetrate and fill the pore space between fine particles. In this study a series of laboratory pressure grouting and leaching tests were conducted to simulate and assess the effectiveness of polyurethane grouting for immobilizing contaminants in DVZs. Soil with fine particles was prepared with <sup>127</sup>I (as iodide) that served as a non-radioactive surrogate for radioactive <sup>129</sup>I. After grouting and curing, leaching tests were used to measure and compare contaminant diffusivity and leachability index values. Additionally, changes in porosity and saturated hydraulic conductivity of grouted soil were measured. X-Ray Computer Tomography (XCT) results showed that the cured polyurethane was distributed nearly homogeneously and approximately half of the voids were filled with cured polyurethane. Grouting reduced the saturated hydraulic conductivity of soil by 37 %. The effective diffusivity decreased by more than 80 % as compared with the ungrouted soil. The leachability index of the grouted soil was 6.5; meeting the criteria established by the U.S. Nuclear Regulatory Commission (NRC) standard. The results obtained in this study provide a valuable assessment of polyurethane grouting for iodide immobilization in the DVZ and indicate this approach may be a viable method for contaminant remediation in DVZ soils.</div></div>","PeriodicalId":11567,"journal":{"name":"Engineering Geology","volume":"347 ","pages":"Article 107945"},"PeriodicalIF":6.9,"publicationDate":"2025-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143083367","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Pull-out capacity and failure mechanism of suction anchors in clay considering trench configuration and local scour effects

IF 6.9 1区工程技术 Q1 ENGINEERING, GEOLOGICAL

Engineering Geology

Pub Date : 2025-01-28 DOI: 10.1016/j.enggeo.2025.107942

Min-Hao Zhang , Zhen-Yu Yin , Yong Fu

Seabed trenching is a common geological and geotechnical hazard encountered in offshore engineering, potentially compromising the pull-out capacity of suction anchors and posing risks to mooring systems over time. Currently, to ensure conservative design and facilitate modelling convenience, many relevant studies simplify the trench configurations compared to their in-situ conditions which may lead to inaccurate estimation of trench influence. Moreover, the combined effect of trench and local scour is rarely addressed. Therefore, this paper aims to investigate the impact of various trench transversal and longitudinal geometric configurations on undrained pull-out capacity and failure mechanisms of suction anchors in clay considering local scour phenomena. Two distinct downward trends in the pull-out capacity for trench width expansion and trench depth extension are revealed. Comparisons between simplified and realistic trench configurations are conducted and it is recommended to model the realistic trench configurations for accurate estimation of capacity loss. Scenarios involving simultaneous trenches and local scours result in a more significant reduction in pull-out capacity compared to individual trenches. Based on the analyses results, a systematic calculation framework is proposed to estimate the pull-out capacity during trench development. Furthermore, two design considerations are examined with the conclusions that relocating padeye depth towards shallower positions to reduce trench depth cannot achieve higher capacity and selecting suction anchors with larger aspect ratios should be preferred choices considering material cost. These findings can assist in estimating capacity loss and optimizing anchor design when encountering trench-related issues in engineering practice.

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引用次数: 0