Soils and Foundations最新文献_第7页

An approach for predicting earthquake-induced permanent displacements of embedded cantilever walls in soils with cohesion 含黏聚土中预埋悬臂墙地震永久位移预测方法

IF 3.3 2区工程技术 Q2 ENGINEERING, GEOLOGICAL

Soils and Foundations

Pub Date : 2025-06-30 DOI: 10.1016/j.sandf.2025.101649

Luigi Pugliese, Antonello Troncone, Andrea Parise, Enrico Conte

Prediction of the earthquake-induced permanent displacements of retaining structures is a key step in the context of a performance-based design approach. For retaining walls with shallow foundations, this issue is usually dealt with using the well-known Newmark sliding block method. However, several studies have shown that this method is unsuitable to provide a trustworthy prediction of the permanent displacements undergone by the embedded cantilever retaining walls under seismic loading. To overcome this drawback, a new method of practical interest is proposed in the present study for a prediction of the earthquake-induced permanent displacement of these structures. In such a method, the wall movements are evaluated solving a simple equation of motion whenever the ground acceleration exceeds a critical value. This latter value is updated during the seismic event by calculating the forces acting on the wall by means of a closed form solution recently derived by the authors. The method is simple to use and requires few conventional parameters as input data. These features make it suitable for current applications. To assess the predictive capability of the present method, comparisons with the results of a centrifuge test documented in the literature and with those of a large number of ideal case studies solved using a finite element code, are presented. The effectiveness of some measures to reduce the wall displacements is also discussed.

在基于性能的设计方法中，地震引起的挡土结构永久位移的预测是关键的一步。对于基础较浅的挡土墙，通常采用著名的纽马克滑块法进行处理。然而，一些研究表明，这种方法不适合为地震荷载作用下预埋悬臂挡土墙的永久位移提供可靠的预测。为了克服这一缺点，本研究提出了一种实用的新方法来预测这些结构的地震引起的永久位移。在这种方法中，当地面加速度超过一个临界值时，墙体的运动是通过求解一个简单的运动方程来评估的。后一个值在地震事件期间通过计算作用在墙壁上的力，通过作者最近导出的封闭形式解来更新。该方法使用简单，需要的常规参数很少。这些特性使其适合当前的应用。为了评估本方法的预测能力，与文献中记录的离心机测试结果以及使用有限元代码解决的大量理想案例研究的结果进行了比较。讨论了减小墙体位移的一些措施的有效性。

{"title":"An approach for predicting earthquake-induced permanent displacements of embedded cantilever walls in soils with cohesion","authors":"Luigi Pugliese, Antonello Troncone, Andrea Parise, Enrico Conte","doi":"10.1016/j.sandf.2025.101649","DOIUrl":"10.1016/j.sandf.2025.101649","url":null,"abstract":"<div><div>Prediction of the earthquake-induced permanent displacements of retaining structures is a key step in the context of a performance-based design approach. For retaining walls with shallow foundations, this issue is usually dealt with using the well-known Newmark sliding block method. However, several studies have shown that this method is unsuitable to provide a trustworthy prediction of the permanent displacements undergone by the embedded cantilever retaining walls under seismic loading. To overcome this drawback, a new method of practical interest is proposed in the present study for a prediction of the earthquake-induced permanent displacement of these structures. In such a method, the wall movements are evaluated solving a simple equation of motion whenever the ground acceleration exceeds a critical value. This latter value is updated during the seismic event by calculating the forces acting on the wall by means of a closed form solution recently derived by the authors. The method is simple to use and requires few conventional parameters as input data. These features make it suitable for current applications. To assess the predictive capability of the present method, comparisons with the results of a centrifuge test documented in the literature and with those of a large number of ideal case studies solved using a finite element code, are presented. The effectiveness of some measures to reduce the wall displacements is also discussed.</div></div>","PeriodicalId":21857,"journal":{"name":"Soils and Foundations","volume":"65 4","pages":"Article 101649"},"PeriodicalIF":3.3,"publicationDate":"2025-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144518750","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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

Seepage pressure distribution of gas jet flow in loess 黄土中气体射流渗流压力分布

IF 3.3 2区工程技术 Q2 ENGINEERING, GEOLOGICAL

Soils and Foundations

Pub Date : 2025-06-26 DOI: 10.1016/j.sandf.2025.101648

Changhui Gao , Songyu Liu , Guangyin Du , Mei Bai , Yankai Wu , Runmin Hao

This study aims to investigate the permeation mechanisms and pressure distribution of gas jets in collapsible loess during pneumatic-vibratory probe compaction (PVPC). Indoor model tests were performed to analyze the behavior of continuous gas jet injection, and a seepage pressure distribution model was developed to characterize gas flow in unsaturated loess. The results show that pulsating gas jets disrupt the soil structure near the nozzle, enabling gas penetration driven by internal pressure differentials and leading to the gradual formation of continuous fractures. Gas pressure measurements at the opposite end of the soil layer indicate an initial pressure rise that stabilizes over time, with thinner soil layers showing more pronounced responses. The proposed model effectively captures the dynamic behavior of gas flow, illustrating a rapid decline in seepage pressure over time and a slow increase in seepage distance. These findings enhance the understanding of gas jet permeation and provide practical guidance for optimizing PVPC parameters, further advancing its application in loess foundation improvement within geotechnical engineering.

研究了湿陷性黄土在气振探测压实过程中气体射流的渗透机理和压力分布。通过室内模型试验分析了气体连续喷射的特性，建立了非饱和黄土中气体流动的渗流压力分布模型。结果表明：脉动气体射流破坏了喷口附近的土体结构，使气体在内部压差的驱动下穿透，逐渐形成连续裂缝；在土层另一端的气体压力测量表明，随着时间的推移，初始压力上升趋于稳定，土层越薄，反应越明显。该模型有效地捕捉了气体流动的动态特性，显示了渗流压力随时间的快速下降和渗流距离的缓慢增加。这些研究结果增强了对气体射流渗透的认识，为优化PVPC参数提供了实践指导，进一步推进了其在岩土工程中黄土地基加固中的应用。

{"title":"Seepage pressure distribution of gas jet flow in loess","authors":"Changhui Gao , Songyu Liu , Guangyin Du , Mei Bai , Yankai Wu , Runmin Hao","doi":"10.1016/j.sandf.2025.101648","DOIUrl":"10.1016/j.sandf.2025.101648","url":null,"abstract":"<div><div>This study aims to investigate the permeation mechanisms and pressure distribution of gas jets in collapsible loess during pneumatic-vibratory probe compaction (PVPC). Indoor model tests were performed to analyze the behavior of continuous gas jet injection, and a seepage pressure distribution model was developed to characterize gas flow in unsaturated loess. The results show that pulsating gas jets disrupt the soil structure near the nozzle, enabling gas penetration driven by internal pressure differentials and leading to the gradual formation of continuous fractures. Gas pressure measurements at the opposite end of the soil layer indicate an initial pressure rise that stabilizes over time, with thinner soil layers showing more pronounced responses. The proposed model effectively captures the dynamic behavior of gas flow, illustrating a rapid decline in seepage pressure over time and a slow increase in seepage distance. These findings enhance the understanding of gas jet permeation and provide practical guidance for optimizing PVPC parameters, further advancing its application in loess foundation improvement within geotechnical engineering.</div></div>","PeriodicalId":21857,"journal":{"name":"Soils and Foundations","volume":"65 4","pages":"Article 101648"},"PeriodicalIF":3.3,"publicationDate":"2025-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144481271","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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

Investigation of acting load and mechanical characteristics of shield tunnel lining in upper-soft and lower-hard stratum 上软下硬地层盾构隧道衬砌作用荷载及力学特性研究

IF 3.3 2区工程技术 Q2 ENGINEERING, GEOLOGICAL

Soils and Foundations

Pub Date : 2025-06-26 DOI: 10.1016/j.sandf.2025.101647

Tao Zhang , Yufeng Shi , Shuying Wang , Menghao Hu , Sijin He

When shield tunnels traverse the upper-soft and lower-hard stratum, the pronounced geological differences lead to uneven stress distribution on the segmental lining, thereby intensifying both construction challenges and safety risks. Investigating the loading conditions and mechanical characteristics of tunnel linings in such strata is imperative. Therefore, field measurements were conducted at two shield tunnel construction sites along Nanchang Metro Line 1, specifically within a silty clay-gravel layer and a homogeneous sand layer. The acting load and internal forces of the segmental lining were monitored over an extended period. By analyzing the monitoring data, the variation patterns of the loads acting on the segmental lining in the upper-soft and lower-hard stratum during the construction stage were summarized. Furthermore, a comparative analysis was carried out between the measured loading conditions and the theoretical analytical solutions. Subsequently, a refined numerical simulation incorporating bolt joints and bolt preload on the segment was performed to further explore the mechanical behavior of the segmental lining, with a comparison to the measured internal force data. The results indicate that synchronous grouting at the shield tail significantly affects the earth pressure in the upper soft soil layer, with the maximum earth pressure induced by synchronous grouting being approximately 1.9 times the final stable value. The vertical earth pressure in the upper part of the segmental lining exhibits a characteristic pattern of being “large in the middle and small at both ends”, with the measured maximum value after stabilization corresponding to approximately 72% of the theoretical value predicted by Terzaghi’s theory. Notably, a sudden change in lateral earth pressure is observed at the stratum interface. The bending moment and axial force at the invert of the tunnel segment are comparatively smaller than those at the vault. Additionally, the development of internal forces within the segment is fairly constrained in the lower hard stratum.

盾构隧道穿越上软下硬地层时，地质差异明显，导致管片衬砌应力分布不均匀，加剧了施工挑战和安全风险。研究此类地层中隧道衬砌的受力条件和力学特性是十分必要的。因此，在南昌地铁1号线的两个盾构隧道施工现场进行了现场测量，特别是在粉质粘土-砾石层和均匀砂层中。长时间监测了分段衬砌的作用荷载和内力。通过对监测数据的分析，总结了上软下硬地层中管片衬砌在施工阶段荷载的变化规律。并将实测载荷条件与理论解析解进行了对比分析。随后，进行了包含螺栓连接和螺栓预紧力的精细化数值模拟，以进一步探索管片衬砌的力学行为，并与测量的内力数据进行了比较。结果表明：盾构尾端同步注浆对上部软土层土压力影响显著，同步注浆引起的最大土压力约为最终稳定值的1.9倍；管片衬砌上部竖向土压力呈现“中间大、两端小”的特征，稳定后的实测最大值约为Terzaghi理论预测的理论值的72%。值得注意的是，在地层界面处观察到侧向土压力的突然变化。隧道段仰拱处的弯矩和轴力相对小于拱顶处。此外，在较低的硬地层中，段内内力的发展受到相当大的限制。

{"title":"Investigation of acting load and mechanical characteristics of shield tunnel lining in upper-soft and lower-hard stratum","authors":"Tao Zhang , Yufeng Shi , Shuying Wang , Menghao Hu , Sijin He","doi":"10.1016/j.sandf.2025.101647","DOIUrl":"10.1016/j.sandf.2025.101647","url":null,"abstract":"<div><div>When shield tunnels traverse the upper-soft and lower-hard stratum, the pronounced geological differences lead to uneven stress distribution on the segmental lining, thereby intensifying both construction challenges and safety risks. Investigating the loading conditions and mechanical characteristics of tunnel linings in such strata is imperative. Therefore, field measurements were conducted at two shield tunnel construction sites along Nanchang Metro Line 1, specifically within a silty clay-gravel layer and a homogeneous sand layer. The acting load and internal forces of the segmental lining were monitored over an extended period. By analyzing the monitoring data, the variation patterns of the loads acting on the segmental lining in the upper-soft and lower-hard stratum during the construction stage were summarized. Furthermore, a comparative analysis was carried out between the measured loading conditions and the theoretical analytical solutions. Subsequently, a refined numerical simulation incorporating bolt joints and bolt preload on the segment was performed to further explore the mechanical behavior of the segmental lining, with a comparison to the measured internal force data. The results indicate that synchronous grouting at the shield tail significantly affects the earth pressure in the upper soft soil layer, with the maximum earth pressure induced by synchronous grouting being approximately 1.9 times the final stable value. The vertical earth pressure in the upper part of the segmental lining exhibits a characteristic pattern of being “large in the middle and small at both ends”, with the measured maximum value after stabilization corresponding to approximately 72% of the theoretical value predicted by Terzaghi’s theory. Notably, a sudden change in lateral earth pressure is observed at the stratum interface. The bending moment and axial force at the invert of the tunnel segment are comparatively smaller than those at the vault. Additionally, the development of internal forces within the segment is fairly constrained in the lower hard stratum.</div></div>","PeriodicalId":21857,"journal":{"name":"Soils and Foundations","volume":"65 4","pages":"Article 101647"},"PeriodicalIF":3.3,"publicationDate":"2025-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144481272","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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

Experimental investigations and sustainability assessments of ground improvement studies of expansive soils 膨胀土地基改良试验研究及可持续性评价

IF 3.3 2区工程技术 Q2 ENGINEERING, GEOLOGICAL

Soils and Foundations

Pub Date : 2025-06-26 DOI: 10.1016/j.sandf.2025.101637

Anand J. Puppala , Nripojyoti Biswas , Md Ashrafuzzaman Khan , Surya S.C. Congress

Expanding and maintaining transportation network assets on shrink-swell soils is a major problem for civil infrastructure owners and agencies across the world. Particularly, lightweight structures such as pavements experience distress due to differential heaving, cracking, shoulder dropping, and others. They can be primarily attributed to non-uniform moisture cycles, which severely impact both the short- and long-term performance of the structures. Among the available ground improvement techniques, both traditional and non-traditional methods are being effectively used to improve soil engineering properties and reduce distress during the service life period of the infrastructure asset. Novel chemical treatment methods and innovative geosynthetics have been employed to mitigate the distresses caused by shrink/swell movements from underlying expansive soils. The research team has studied applications of co-additives such as Geo-polymers and silica fines for stabilizing sulfate-rich expansive subsoils. An overview of stabilization studies using chemical additives, along with comprehensive sustainability analyses of these methods, were discussed in this paper. In addition, case studies on the application of geosynthetic products, including geocells and wicking geotextiles, for improvements of pavement performance built over expansive soils, are provided. Overall, the application of these new ground improvement techniques will be of immense help to infrastructure and transportation sectors and agencies as their usage would promote sustainable benefits with a higher return on investment.

在收缩膨胀土上扩展和维护交通网络资产是世界各地民用基础设施所有者和机构面临的主要问题。特别是，轻质结构，如路面，由于不同的起伏，开裂，肩下垂，和其他的痛苦。它们主要归因于不均匀的水分循环，这严重影响了结构的短期和长期性能。在现有的地基改善技术中，传统和非传统的方法都被有效地用于改善基础设施资产使用寿命期间的土壤工程特性和减少困扰。采用了新的化学处理方法和创新的土工合成材料来减轻下伏膨胀土的收缩/膨胀运动所造成的痛苦。研究小组研究了共添加剂的应用，如土工聚合物和二氧化硅粉，以稳定富含硫酸盐的膨胀底土。本文概述了化学添加剂稳定研究的概况，以及这些方法的综合可持续性分析。此外，还提供了应用土工合成产品的案例研究，包括土工细胞和吸芯土工织物，以改善在膨胀土壤上建造的路面性能。总的来说，这些新的地面改善技术的应用将对基础设施和运输部门和机构有巨大的帮助，因为它们的使用将促进可持续的利益，并带来更高的投资回报。

{"title":"Experimental investigations and sustainability assessments of ground improvement studies of expansive soils","authors":"Anand J. Puppala , Nripojyoti Biswas , Md Ashrafuzzaman Khan , Surya S.C. Congress","doi":"10.1016/j.sandf.2025.101637","DOIUrl":"10.1016/j.sandf.2025.101637","url":null,"abstract":"<div><div>Expanding and maintaining transportation network assets on shrink-swell soils is a major problem for civil infrastructure owners and agencies across the world. Particularly, lightweight structures such as pavements experience distress due to differential heaving, cracking, shoulder dropping, and others. They can be primarily attributed to non-uniform moisture cycles, which severely impact both the short- and long-term performance of the structures. Among the available ground improvement techniques, both traditional and non-traditional methods are being effectively used to improve soil engineering properties and reduce distress during the service life period of the infrastructure asset. Novel chemical treatment methods and innovative geosynthetics have been employed to mitigate the distresses caused by shrink/swell movements from underlying expansive soils. The research team has studied applications of co-additives such as Geo-polymers and silica fines for stabilizing sulfate-rich expansive subsoils. An overview of stabilization studies using chemical additives, along with comprehensive sustainability analyses of these methods, were discussed in this paper. In addition, case studies on the application of geosynthetic products, including geocells and wicking geotextiles, for improvements of pavement performance built over expansive soils, are provided. Overall, the application of these new ground improvement techniques will be of immense help to infrastructure and transportation sectors and agencies as their usage would promote sustainable benefits with a higher return on investment.</div></div>","PeriodicalId":21857,"journal":{"name":"Soils and Foundations","volume":"65 4","pages":"Article 101637"},"PeriodicalIF":3.3,"publicationDate":"2025-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144491129","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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

Role of mineralogy on the undrained monotonic simple shear response of compacted filtered copper tailings 矿物学对压实过滤铜尾矿不排水单调单剪响应的影响

IF 3.3 2区工程技术 Q2 ENGINEERING, GEOLOGICAL

Soils and Foundations

Pub Date : 2025-06-25 DOI: 10.1016/j.sandf.2025.101636

Rodrigo Zorzal Velten , Carina Ulsen , João Paulo Rodrigues da Costa , Carlos Alex Alves Lima , Maiki Mafessoli , João Vítor de Azambuja Carvalho , Nilo Cesar Consoli

Tailings are anthropic materials whose behavior can be greatly affected by the mineralogy of their particles and the fabric formed. This paper focuses on the effects of tailings composition under plane strain conditions. For this, two copper tailings from distinct mines are studied. The tailings present a similar particle grading and morphology, so the main difference between them is restricted to mineralogy. Three compaction degrees and four effective confining pressure values (ranging from 50 to 400 kPa) were adopted. For the first time, the results of copper tailings under plane strain conditions are presented in the light of critical state soil mechanics due to the use of a simple shear apparatus equipped with backpressure and known horizontal stresses. The results revealed the influence of mineralogy on the critical state parameter M and the shape of the v – log p′ critical state lines. This highlights the importance of acknowledging mineralogy influence for properly designing tailings storage facilities.

尾矿是一种人为物质，其行为受其颗粒的矿物学特征和所形成的织物的影响很大。研究了平面应变条件下尾砂成分对尾砂的影响。为此，对两个不同矿山的铜尾矿进行了研究。两种尾矿的颗粒级配和形态相似，主要区别在于矿物学。采用3种压实度和4种有效围压值（50 ~ 400kpa）。利用具有背压和已知水平应力的简易剪切装置，首次从临界状态土力学角度给出了平面应变条件下铜尾砂的剪切结果。结果揭示了矿物学对临界状态参数M和v - log p '临界状态线形状的影响。这突出了认识矿物学影响对合理设计尾矿储存设施的重要性。

{"title":"Role of mineralogy on the undrained monotonic simple shear response of compacted filtered copper tailings","authors":"Rodrigo Zorzal Velten , Carina Ulsen , João Paulo Rodrigues da Costa , Carlos Alex Alves Lima , Maiki Mafessoli , João Vítor de Azambuja Carvalho , Nilo Cesar Consoli","doi":"10.1016/j.sandf.2025.101636","DOIUrl":"10.1016/j.sandf.2025.101636","url":null,"abstract":"<div><div>Tailings are anthropic materials whose behavior can be greatly affected by the mineralogy of their particles and the fabric formed. This paper focuses on the effects of tailings composition under plane strain conditions. For this, two copper tailings from distinct mines are studied. The tailings present a similar particle grading and morphology, so the main difference between them is restricted to mineralogy. Three compaction degrees and four effective confining pressure values (ranging from 50 to 400 kPa) were adopted. For the first time, the results of copper tailings under plane strain conditions are presented in the light of critical state soil mechanics due to the use of a simple shear apparatus equipped with backpressure and known horizontal stresses. The results revealed the influence of mineralogy on the critical state parameter <em>M</em> and the shape of the <em>v</em> – log <em>p′</em> critical state lines. This highlights the importance of acknowledging mineralogy influence for properly designing tailings storage facilities.</div></div>","PeriodicalId":21857,"journal":{"name":"Soils and Foundations","volume":"65 4","pages":"Article 101636"},"PeriodicalIF":3.3,"publicationDate":"2025-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144481273","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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

Effect of fines contents on uplift behavior of underground structures in liquefiable ground 细粒含量对液化地基地下结构上拔性能的影响

IF 3.3 2区工程技术 Q2 ENGINEERING, GEOLOGICAL

Soils and Foundations

Pub Date : 2025-06-20 DOI: 10.1016/j.sandf.2025.101623

Fernaldy Sebastian Santoso , Kenji Watanabe

Research on liquefaction began decades ago, with clean sand being the main material . Recently, as it has been proven that fines-containing materials are also suspected to be liquefied, additional studies, mainly elementary tests, have been conducted. However, few liquefaction model experiments have been conducted in which the fines content is varied. This is because it is difficult to completely saturate a model ground with fines and conduct highly reproducible model experiments. In the present study, therefore, a modified vacuum container sand box and large-size vacuum saturation method were adopted to perfectly saturate model grounds with different non-plastic fines contents. A pipe model was placed in the ground to investigate the uplift behavior of an underground structure induced by liquefaction.

The experiments revealed that a ground with a higher fines content induced a lower total uplift displacement in the pipe model than grounds with a lower or no fines content. Interestingly, these results differ from the liquefaction properties of the fines-mixed sand observed in previous elementary tests. The discrepancy is probably due to the effects of the strength recovery of the ground, low void ratio, low permeability, and high viscous resistance of such a soil with fines.

液化的研究开始于几十年前，以干净的沙子为主要材料。最近，由于已证明含有细颗粒的材料也被怀疑是液化的，因此进行了更多的研究，主要是初级试验。然而，很少进行细粒含量变化的液化模型实验。这是因为很难用细粉使模型地面完全饱和并进行高重复性的模型实验。因此，本研究采用改进的真空容器砂箱和大尺寸真空饱和法对不同非塑性细粒含量的模型地基进行了完全饱和。为了研究液化引起地下结构的隆升行为，在地下放置了一个管道模型。试验结果表明，细粒含量较高的地基比细粒含量较低或不含细粒的地基在管道模型中引起的总上拔位移较小。有趣的是，这些结果不同于在以前的初级试验中观察到的细混合砂的液化特性。这种差异可能是由于地基的强度恢复、低空隙比、低渗透性和高粘阻等因素的影响。

{"title":"Effect of fines contents on uplift behavior of underground structures in liquefiable ground","authors":"Fernaldy Sebastian Santoso , Kenji Watanabe","doi":"10.1016/j.sandf.2025.101623","DOIUrl":"10.1016/j.sandf.2025.101623","url":null,"abstract":"<div><div>Research on liquefaction began decades ago, with clean sand being the main material . Recently, as it has been proven that fines-containing materials are also suspected to be liquefied, additional studies, mainly elementary tests, have been conducted. However, few liquefaction model experiments have been conducted in which the fines content is varied. This is because it is difficult to completely saturate a model ground with fines and conduct highly reproducible model experiments. In the present study, therefore, a modified vacuum container sand box and large-size vacuum saturation method were adopted to perfectly saturate model grounds with different non-plastic fines contents. A pipe model was placed in the ground to investigate the uplift behavior of an underground structure induced by liquefaction.</div><div>The experiments revealed that a ground with a higher fines content induced a lower total uplift displacement in the pipe model than grounds with a lower or no fines content. Interestingly, these results differ from the liquefaction properties of the fines-mixed sand observed in previous elementary tests. The discrepancy is probably due to the effects of the strength recovery of the ground, low void ratio, low permeability, and high viscous resistance of such a soil with fines.</div></div>","PeriodicalId":21857,"journal":{"name":"Soils and Foundations","volume":"65 4","pages":"Article 101623"},"PeriodicalIF":3.3,"publicationDate":"2025-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144331300","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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

Deformation, resistance characteristics, and scale effects of rockfall protection soil embankments under static loading 静力荷载作用下防落石土路堤变形、阻力特性及尺度效应

IF 3.3 2区工程技术 Q2 ENGINEERING, GEOLOGICAL

Soils and Foundations

Pub Date : 2025-06-20 DOI: 10.1016/j.sandf.2025.101634

Yoshiyuki Oguri , Kenichi Maeda , Keisuke Kondo , Takuro Nakamura , Yuji Ushiwatari , Naoto Naito , Masato Komuro

Rockfall protection soil embankments are structures that can effectively reduce rockfall hazards along roads. They are economical and easy to construct and maintain by using locally available soil. However, a performance design method for rockfall protection soil embankments has not yet been established, and is the goal of this study. In the present study, static loading tests were conducted using two different weight shapes to clarify the influence of the weight shape on the deformation behavior of soil embankments. Based on these tests, the punching shear failure mechanism of the soil embankments was investigated. The influence of the model scale (the scale effect) on the deformation failure behavior of the soil embankments was clarified through static loading tests on reduced models at three different scales. From these model experiments, the surface deformation, internal deformation, and load–penetration relationships of the soil embankments were summarized. The results indicated that the spherical weight damaged a wider area than the polyhedral weight, and the maximum and ultimate loads exhibited a constant relationship with the deformation of the soil embankment extension between the model scales.

防落石土路堤是一种能有效减少道路沿线落石灾害的结构。它们经济且易于使用当地可用的土壤来建造和维护。然而，目前还没有建立起防落土路堤的性能设计方法，这也是本研究的目标。本研究采用两种不同重量形状进行静载试验，以阐明重量形状对土路堤变形行为的影响。在此基础上，对土路堤冲剪破坏机理进行了研究。通过对三种不同尺度的模型进行静载试验，阐明了模型尺度（尺度效应）对土路堤变形破坏行为的影响。通过这些模型试验，总结了土路堤的表面变形、内部变形和荷载-侵彻关系。结果表明，球形荷载比多面体荷载的破坏面积更大，最大和极限荷载与模型尺度之间的土路堤延伸变形呈恒定关系。

{"title":"Deformation, resistance characteristics, and scale effects of rockfall protection soil embankments under static loading","authors":"Yoshiyuki Oguri , Kenichi Maeda , Keisuke Kondo , Takuro Nakamura , Yuji Ushiwatari , Naoto Naito , Masato Komuro","doi":"10.1016/j.sandf.2025.101634","DOIUrl":"10.1016/j.sandf.2025.101634","url":null,"abstract":"<div><div>Rockfall protection soil embankments are structures that can effectively reduce rockfall hazards along roads. They are economical and easy to construct and maintain by using locally available soil. However, a performance design method for rockfall protection soil embankments has not yet been established, and is the goal of this study. In the present study, static loading tests were conducted using two different weight shapes to clarify the influence of the weight shape on the deformation behavior of soil embankments. Based on these tests, the punching shear failure mechanism of the soil embankments was investigated. The influence of the model scale (the scale effect) on the deformation failure behavior of the soil embankments was clarified through static loading tests on reduced models at three different scales. From these model experiments, the surface deformation, internal deformation, and load–penetration relationships of the soil embankments were summarized. The results indicated that the spherical weight damaged a wider area than the polyhedral weight, and the maximum and ultimate loads exhibited a constant relationship with the deformation of the soil embankment extension between the model scales.</div></div>","PeriodicalId":21857,"journal":{"name":"Soils and Foundations","volume":"65 4","pages":"Article 101634"},"PeriodicalIF":3.3,"publicationDate":"2025-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144321400","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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

Strengthening the subgrade clay soil using nano chemical stabilisation 利用纳米化学稳定技术加固路基粘土

IF 3.3 2区工程技术 Q2 ENGINEERING, GEOLOGICAL

Soils and Foundations

Pub Date : 2025-06-18 DOI: 10.1016/j.sandf.2025.101638

Kodi Rangaswamy, Regi P. Mohan

Nowadays, non-traditional eco-friendly nanomaterial additives are widely utilized in the geotechnical stabilization of soft soils. The application of materials developed using nanotechnology in stabilizing soils effectively reduces or replaces the utility of cementation products like cement and lime, which leads to environmental pollution. This article evaluates the efficacy of organosilane nano-chemical additive with 1 % cement binder in improving the strength properties of soft soil used for road-based applications. A series of experimental tests were conducted to characterize the geotechnical properties of soft clay and nano-chemical-treated soft soils with 1 % cement binder, including soil gradation, consistency limits, compaction, unconfined compression, and California bearing ratio (CBR) strength, and microstructural and chemical analysis. A small dosage of 1 % cement was added to the parent clay to accelerate the cementitious reactions in soil treated with a nano-chemical additive. The dosage of nano-chemical additives used was varied from 0.03 to 0.05 % for the present study. The treated clayey soil is examined for the optimum dosage corresponding to the highest unconfined compression strength of soil samples cured up to 28 days. Test results show that the soft clay treated with organosilane-based nano-chemical at an optimum dosage of 0.045 % and 1 % cement binder has attained the maximum unconfined compression and CBR strengths. SEM and FTIR results postulate the microstructural and chemical interactions involved in supporting the mechanism of improvement in the strength of treated soils.

目前，非传统的环保纳米材料添加剂在软土的岩土稳定中得到了广泛的应用。利用纳米技术开发的材料在稳定土壤中的应用，有效地减少或取代了水泥和石灰等胶结产品的使用，从而导致环境污染。本文评价了有机硅烷纳米化学添加剂添加1%水泥粘结剂对改善道路用软土强度性能的效果。研究人员进行了一系列实验测试，以表征含有1%水泥粘合剂的软粘土和纳米化学处理软土的岩土力学特性，包括土壤级配、稠度极限、压实、无侧限压缩和加州承载比（CBR）强度，以及微观结构和化学分析。在母质粘土中加入少量1%的水泥，以加速纳米化学添加剂处理过的土壤的胶凝反应。在本研究中，纳米化学添加剂的用量为0.03% ~ 0.05%。对处理后的粘土进行了试验，以确定固化至28天的土样的最高无侧限抗压强度所对应的最佳用量。试验结果表明，有机硅基纳米化学剂在掺量为0.045%、水泥粘结剂掺量为1%的条件下处理软粘土获得了最大的无侧限抗压强度和CBR强度。SEM和FTIR结果假设微观结构和化学相互作用参与支持改善处理土壤强度的机制。

{"title":"Strengthening the subgrade clay soil using nano chemical stabilisation","authors":"Kodi Rangaswamy, Regi P. Mohan","doi":"10.1016/j.sandf.2025.101638","DOIUrl":"10.1016/j.sandf.2025.101638","url":null,"abstract":"<div><div>Nowadays, non-traditional eco-friendly nanomaterial additives are widely utilized in the geotechnical stabilization of soft soils. The application of materials developed using nanotechnology in stabilizing soils effectively reduces or replaces the utility of cementation products like cement and lime, which leads to environmental pollution. This article evaluates the efficacy of organosilane nano-chemical additive with 1 % cement binder in improving the strength properties of soft soil used for road-based applications. A series of experimental tests were conducted to characterize the geotechnical properties of soft clay and nano-chemical-treated soft soils with 1 % cement binder, including soil gradation, consistency limits, compaction, unconfined compression, and California bearing ratio (CBR) strength, and microstructural and chemical analysis. A small dosage of 1 % cement was added to the parent clay to accelerate the cementitious reactions in soil treated with a nano-chemical additive. The dosage of nano-chemical additives used was varied from 0.03 to 0.05 % for the present study. The treated clayey soil is examined for the optimum dosage corresponding to the highest unconfined compression strength of soil samples cured up to 28 days. Test results show that the soft clay treated with organosilane-based nano-chemical at an optimum dosage of 0.045 % and 1 % cement binder has attained the maximum unconfined compression and CBR strengths. SEM and FTIR results postulate the microstructural and chemical interactions involved in supporting the mechanism of improvement in the strength of treated soils.</div></div>","PeriodicalId":21857,"journal":{"name":"Soils and Foundations","volume":"65 4","pages":"Article 101638"},"PeriodicalIF":3.3,"publicationDate":"2025-06-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144308095","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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

Centrifuge model tests on liquefaction-induced settlement of river embankments reinforced by floating-type cement treatment method 浮式水泥加固河堤液化沉降离心模型试验

IF 3.3 2区工程技术 Q2 ENGINEERING, GEOLOGICAL

Soils and Foundations

Pub Date : 2025-06-12 DOI: 10.1016/j.sandf.2025.101633

Masahide Otsubo , Yuta Miura, Kazuya Ueda, Shunsuke Tanimoto, Masanori Ishihara, Tetsuya Sasaki

Loose sandy soil layers are prone to liquefaction under strong earthquakes, causing damage to civil engineering structures inside or upon the liquefied ground. According to the present Japanese design guideline on liquefaction countermeasures for river levees, the entire depth of the liquefiable subsoil below river embankments should be improved. However, this approach is not economical against deep liquefiable subsoil. To rationalize the design approach, this contribution investigated the performance of a floating-type cement treatment method, in which only the shallower part of the liquefiable subsoil is reinforced. A series of centrifuge shaking table model tests was conducted under a 50

g

environment. The depth of improvement (cement treatment) was varied systematically, and the effect of the sloping ground was examined. The experimental results revealed that the settlements of river embankments can be reduced linearly by increasing the depth of improvement. Moreover, the acceleration of embankments can be reduced drastically by the vibration-isolation effect between the cement-treated soil and the liquefiable soil. These effects contribute to the safe retention of the embankment shape even when the liquefied sloping ground causes lateral flows. Towards practical implementation, discussions on the effect of permeability on cement-treated soil were expanded. Furthermore, the stress acting on cement-treated soil during shaking was measured using an acrylic block to explain the occurrence of cracks in the soil.

松散的沙质土层在强震作用下容易发生液化，对液化地面内部或上面的土木工程结构造成破坏。根据日本现行的河堤液化对策设计指南，应提高河堤以下可液化底土的整体深度。然而，对于深层可液化地基，这种方法并不经济。为了使设计方法合理化，本文研究了浮式水泥处理方法的性能，该方法仅对可液化地基的较浅部分进行加固。在50g环境下进行了一系列离心振动台模型试验。系统地改变了改善（水泥处理）的深度，并对倾斜地面的效果进行了检验。试验结果表明，增加堤防加固深度可以线性降低堤防沉降。此外，水泥处理土与液化土之间的隔振效应可以显著降低路堤的加速度。这些影响有助于即使在液化的倾斜地面引起横向流动时也能安全保持路堤形状。面向实际应用，扩展了对水泥土渗透性影响的讨论。此外，使用丙烯酸块测量了震动过程中作用在水泥处理土壤上的应力，以解释土壤中裂缝的发生。

{"title":"Centrifuge model tests on liquefaction-induced settlement of river embankments reinforced by floating-type cement treatment method","authors":"Masahide Otsubo , Yuta Miura, Kazuya Ueda, Shunsuke Tanimoto, Masanori Ishihara, Tetsuya Sasaki","doi":"10.1016/j.sandf.2025.101633","DOIUrl":"10.1016/j.sandf.2025.101633","url":null,"abstract":"<div><div>Loose sandy soil layers are prone to liquefaction under strong earthquakes, causing damage to civil engineering structures inside or upon the liquefied ground. According to the present Japanese design guideline on liquefaction countermeasures for river levees, the entire depth of the liquefiable subsoil below river embankments should be improved. However, this approach is not economical against deep liquefiable subsoil. To rationalize the design approach, this contribution investigated the performance of a floating-type cement treatment method, in which only the shallower part of the liquefiable subsoil is reinforced. A series of centrifuge shaking table model tests was conducted under a 50<span><math><mrow><mi>g</mi></mrow></math></span> environment. The depth of improvement (cement treatment) was varied systematically, and the effect of the sloping ground was examined. The experimental results revealed that the settlements of river embankments can be reduced linearly by increasing the depth of improvement. Moreover, the acceleration of embankments can be reduced drastically by the vibration-isolation effect between the cement-treated soil and the liquefiable soil. These effects contribute to the safe retention of the embankment shape even when the liquefied sloping ground causes lateral flows. Towards practical implementation, discussions on the effect of permeability on cement-treated soil were expanded. Furthermore, the stress acting on cement-treated soil during shaking was measured using an acrylic block to explain the occurrence of cracks in the soil.</div></div>","PeriodicalId":21857,"journal":{"name":"Soils and Foundations","volume":"65 4","pages":"Article 101633"},"PeriodicalIF":3.3,"publicationDate":"2025-06-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144271980","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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

Rheological properties of deep-sea shallow sediments in the Western Pacific mining area 西太平洋矿区深海浅层沉积物的流变特性

IF 3.3 2区工程技术 Q2 ENGINEERING, GEOLOGICAL

Soils and Foundations

Pub Date : 2025-06-01 DOI: 10.1016/j.sandf.2025.101632

Hao Liu , Zongxiang Xiu , Lejun Liu , Jie Dong , Qiuhong Xie , Mu Huang , Chenwei Luo , Yifeng Zeng , Xingsen Guo

Studying the rheological properties of deep-sea shallow sediments can provide basic mechanical characteristics for designing deep-sea mining vehicles driving on the soft seabed, providing anchoring stability of semi-submersible mining platforms, and assessing submarine landslide hazards. Shallow sediment column samples from the Western Pacific mining area were obtained, and their rheological properties were studied. A series of rheological tests was conducted under different conditions using an RST rheometer. In addition, conventional physical property, mineral composition, and microstructure analyses were conducted. The results showed that shallow sediments have a high liquid limit and plasticity, with flocculent and honeycomb-like flaky structures as the main microstructure types. The rheological properties exhibited typical non-Newtonian fluid characteristics with yield stress and shear-thinning phenomena during the shearing process. In contrast to previous studies on deep-sea soft soil sediments, a remarkable long-range shear-softening stage, called the thixotropic fluid stage, was discovered in the overall rheological curve. A four-stage model is proposed for the transition mechanism of deep-sea shallow sediments from the solid to liquid–solid, solid–liquid transition, thixotropic fluid, and stable fluid stages. The mechanism of the newly added thixotropic fluid stage was quantitatively analyzed using a modified Cross rheological model, and this stage was inferred from the perspective of mineralogy and microstructure. The results of this study can be useful for improving the operational safety and work efficiency of submarine operation equipment for deep-sea mining in the Western Pacific Ocean.

研究深海浅层沉积物的流变特性，可以为设计在软海底行驶的深海采矿车、提供半潜式采矿平台的锚固稳定性以及评估海底滑坡灾害提供基本的力学特性。获取了西太平洋矿区浅层沉积物柱样，对其流变特性进行了研究。利用RST流变仪在不同条件下进行了一系列流变试验。此外，还进行了常规物性、矿物组成和微观结构分析。结果表明：浅层沉积物具有较高的液限和塑性，以絮状和蜂窝状片状结构为主要微观结构类型；剪切过程中出现屈服应力和剪切变薄现象，流变特性表现出典型的非牛顿流体特性。与以往对深海软土沉积物的研究相比，在整体流变曲线中发现了一个显著的长时间剪切软化阶段，即触变流体阶段。提出了深海浅层沉积物从固体到液-固、固-液过渡、触变流体和稳定流体四个阶段的过渡机理模型。采用改进的Cross流变模型定量分析了新增触变流体阶段的机理，并从矿物学和微观结构的角度对该阶段进行了推断。研究结果可为提高西太平洋深海采矿潜艇作业设备的作业安全性和工作效率提供参考。

{"title":"Rheological properties of deep-sea shallow sediments in the Western Pacific mining area","authors":"Hao Liu , Zongxiang Xiu , Lejun Liu , Jie Dong , Qiuhong Xie , Mu Huang , Chenwei Luo , Yifeng Zeng , Xingsen Guo","doi":"10.1016/j.sandf.2025.101632","DOIUrl":"10.1016/j.sandf.2025.101632","url":null,"abstract":"<div><div>Studying the rheological properties of deep-sea shallow sediments can provide basic mechanical characteristics for designing deep-sea mining vehicles driving on the soft seabed, providing anchoring stability of semi-submersible mining platforms, and assessing submarine landslide hazards. Shallow sediment column samples from the Western Pacific mining area were obtained, and their rheological properties were studied. A series of rheological tests was conducted under different conditions using an RST rheometer. In addition, conventional physical property, mineral composition, and microstructure analyses were conducted. The results showed that shallow sediments have a high liquid limit and plasticity, with flocculent and honeycomb-like flaky structures as the main microstructure types. The rheological properties exhibited typical non-Newtonian fluid characteristics with yield stress and shear-thinning phenomena during the shearing process. In contrast to previous studies on deep-sea soft soil sediments, a remarkable long-range shear-softening stage, called the thixotropic fluid stage, was discovered in the overall rheological curve. A four-stage model is proposed for the transition mechanism of deep-sea shallow sediments from the solid to liquid–solid, solid–liquid transition, thixotropic fluid, and stable fluid stages. The mechanism of the newly added thixotropic fluid stage was quantitatively analyzed using a modified Cross rheological model, and this stage was inferred from the perspective of mineralogy and microstructure. The results of this study can be useful for improving the operational safety and work efficiency of submarine operation equipment for deep-sea mining in the Western Pacific Ocean.</div></div>","PeriodicalId":21857,"journal":{"name":"Soils and Foundations","volume":"65 3","pages":"Article 101632"},"PeriodicalIF":3.3,"publicationDate":"2025-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144221511","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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