Geotechnics最新文献_第4页

Geogrid-Enhanced Modulus and Stress Distribution in Clay Soil 粘土中的土工格栅增强模量和应力分布

Geotechnics Pub Date : 2023-12-28 DOI: 10.3390/geotechnics4010003

Qiming Chen

{"title":"Geogrid-Enhanced Modulus and Stress Distribution in Clay Soil","authors":"Qiming Chen","doi":"10.3390/geotechnics4010003","DOIUrl":"https://doi.org/10.3390/geotechnics4010003","url":null,"abstract":"A series of laboratory and large-scale field model footing tests were conducted to assess the modulus and stress distribution behavior of a clayey soil foundation, both with/without geogrid reinforcement, deviating from the conventional approach of evaluating the strength performance, such as bearing capacity. The modulus was evaluated at three settlement ratios of s/B = 1, 3, and 5%, while the stress distribution angle α was estimated at three applied surface pressures of 234 kPa, 468 kPa, and 936 kPa. The results indicated a stiffer load-settlement response when geogrid reinforcement was included. The modulus of reinforced clayey soil remained nearly constant for test sections with the same reinforced ratio, with the modulus improvement increasing as the reinforced ratio (Rr) increased. The modulus improvement also increased with the settlement ratio (s/B). These results demonstrated that the stress distribution improvement decreased as the surface pressure increased. Generally, both the modulus and stress distribution improvement exhibited an increase with an increase in the tensile modulus of the geogrid. While laboratory model tests consistently provided a higher improvement in the modulus than large-scale field model tests in this study due to a higher reinforced ratio, the stress distribution improvement was similar for both.","PeriodicalId":505610,"journal":{"name":"Geotechnics","volume":"224 14","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-12-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139153021","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Determination of Constrained Modulus of Granular Soil from In Situ Tests—Part 1 Analyses 通过原位测试确定粒状土的约束模量--第 1 部分分析

Geotechnics Pub Date : 2023-12-21 DOI: 10.3390/geotechnics4010002

K. Massarsch

{"title":"Determination of Constrained Modulus of Granular Soil from In Situ Tests—Part 1 Analyses","authors":"K. Massarsch","doi":"10.3390/geotechnics4010002","DOIUrl":"https://doi.org/10.3390/geotechnics4010002","url":null,"abstract":"Assessing the constrained modulus is a critical step in calculating settlements in granular soils. This paper describes a novel concept of how the constrained modulus can be derived from seismic tests. The advantages and limitations of seismic laboratory and field tests are addressed. Based on a comprehensive review of laboratory resonant column and torsional shear tests, the most important parameters affecting the shear modulus, such as shear strain and confining stress, are defined quantitatively. Also, Poisson’s ratio, which is needed to convert shear modulus to constrained modulus, is strain-dependent. An empirical relationship is presented from which the variation in the secant shear modulus with shear strain can be defined numerically within a broad strain range (10−4–10−0.5%). The tangent shear modulus was obtained by differentiating the secant shear modulus. According to the tangent modulus concept, the tangent constrained modulus is governed by the modulus number, m, and the stress exponent, j. Laboratory test results on granular soils are reviewed, based on which it is possible to estimate the modulus number during virgin loading and unloading/reloading. A correlation is proposed between the small-strain shear modulus, G0, and the modulus number, m. The modulus number can also be derived from static cone penetration tests, provided that the cone resistance is adjusted with respect to the mean effective stress. In a companion paper, the concepts presented in this paper are applied to data from an experimental site, where different types of seismic tests and cone penetration tests were performed.","PeriodicalId":505610,"journal":{"name":"Geotechnics","volume":"26 22","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-12-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139167297","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Study on the Prediction of Slope Failure and Early Warning Thresholds Based on Model Tests 基于模型试验的斜坡崩塌预测和预警阈值研究

Geotechnics Pub Date : 2023-12-20 DOI: 10.3390/geotechnics4010001

M. Fukuhara, T. Uchimura, Lin Wang, Shangning Tao, Junfeng Tang

{"title":"Study on the Prediction of Slope Failure and Early Warning Thresholds Based on Model Tests","authors":"M. Fukuhara, T. Uchimura, Lin Wang, Shangning Tao, Junfeng Tang","doi":"10.3390/geotechnics4010001","DOIUrl":"https://doi.org/10.3390/geotechnics4010001","url":null,"abstract":"In recent years, slope failure caused by heavy rainfall from linear precipitation bands has occurred frequently, causing extensive damage. Predicting slope failure is an important and necessary issue. A method used to predict the time of failure has been proposed, which focuses on the tertiary stage of the creep theory, shown as V = A/(tr − t), where V is the velocity of displacement, A is a constant, and (tr − t) is the time until failure. To verify this method, indoor model experiments and field monitoring were used to observe the behavior of surface displacement. Seven cases of laboratory experiments were conducted by changing the conditions in the model, such as materials, the thickness of the surface layer, and relative density. Then, two cases of field monitoring slope failure were examined using this method. The results show that, in the tertiary stage of creep theory, the relationship between tilt angle velocity and the time until failure can be expressed as an inversely proportional relationship. When the tilt angle velocity has reached the tertiary creep stage, it initially ranges from 0.01°/h to 0.1°/h; when near failure, it was found to be over 0.1°/h, so, combining this with previous research results, this is a reasonable value as a guideline for an early warning threshold.","PeriodicalId":505610,"journal":{"name":"Geotechnics","volume":"656 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-12-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139170015","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Experimental and Numerical Analysis of Laterally Loaded Single- and Double-Paddled H-Piles in Clay 粘土中横向加载单桩和双桩工字桩的实验和数值分析

Geotechnics Pub Date : 2023-12-15 DOI: 10.3390/geotechnics3040072

Abdelrahman Abouziad, M. H. El Naggar

{"title":"Experimental and Numerical Analysis of Laterally Loaded Single- and Double-Paddled H-Piles in Clay","authors":"Abdelrahman Abouziad, M. H. El Naggar","doi":"10.3390/geotechnics3040072","DOIUrl":"https://doi.org/10.3390/geotechnics3040072","url":null,"abstract":"An efficient foundation system of single- or double-paddled H-piles (PHPs), which comprises steel H-piles fitted with specially configured steel plates (paddles), is proposed to support sound walls subjected to wind loading. The lateral responses of single-paddled (SPHPs) and double-paddled H-piles (DPHPs) installed in clay is evaluated using a comprehensive assessment of the foundation performance via a full-scale lateral load testing program, alongside extensive three-dimensional (3D) nonlinear finite element (FE) analysis. The comparison between the calculated and measured responses of the PHPs demonstrates that the developed numerical model accurately depicts the response of the PHPs under lateral load. The validated numerical model is then used to evaluate the effect of the soil consistency on the lateral response and capacity of the PHPs. The influence of the paddles’ configuration on the lateral response and capacity of the PHPs is also evaluated. Furthermore, the change in the PHP lateral stiffness due to adding a second paddle is also examined. Finally, the influence of the plates on the surrounding soil is investigated by analyzing the formation of the strain field around the pile and evaluating the extent of the soil influence zone at different plate-width-to-pile-flange-width ratios (Wp/Wf). The result of this study indicates that adding plates contributes significantly to the lateral capacity of PHPs in clay and reduces the maximum bending moment. The parametric study reveals that the top 5–6 Wp of the soil have a significant effect on the lateral response of the proposed H-pile. Based on the outcomes of the field tests and numerical analysis, optimal geometrical parameters for paddles are proposed.","PeriodicalId":505610,"journal":{"name":"Geotechnics","volume":"404 ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139178078","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Embankments Reinforced by Vertical Inclusions on Soft Soil: Numerical Study of Stress Redistribution 软土上的垂直夹杂物加固路堤：应力再分布数值研究

Geotechnics Pub Date : 2023-11-23 DOI: 10.3390/geotechnics3040069

Minh-Tuan Pham, Duc‐Dung Pham, Duy-Liem Vu, Daniel Dias

{"title":"Embankments Reinforced by Vertical Inclusions on Soft Soil: Numerical Study of Stress Redistribution","authors":"Minh-Tuan Pham, Duc‐Dung Pham, Duy-Liem Vu, Daniel Dias","doi":"10.3390/geotechnics3040069","DOIUrl":"https://doi.org/10.3390/geotechnics3040069","url":null,"abstract":"Constructing embankments over soft soils is a challenge for geotechnical engineers due to large settlements. Among diverse ground-improvement methods, combining piles and geosynthetics (e.g., geosynthetic-reinforced piles, deep cement mixing columns, geotextile-encased columns) emerges as a reliable solution for time-bound projects and challenging ground conditions. While stress distribution within pile-supported embankments has been extensively studied, the load transfer efficiency of piled solutions with geosynthetic reinforcement remains less explored. The novelty in this study lies in the investigation of three different inclusion solutions from a common control case in the numerical model considering the role of geosynthetic reinforcement. This study investigates the load transfer mechanisms in embankments supported by various techniques including geosynthetic-reinforced piles, deep cement mixing columns, and geosynthetic-encased granular columns. Two-dimensional axisymmetric finite element models were developed for three cases of embankments supported by vertical inclusions. Numerical findings allow clarification of the soft ground and embankment characteristics which influence the arching and membrane efficiencies. Rigid piles outperform deep cement mixing (DCM) columns and geotextile-encased columns (GEC) in reducing settlements of soft ground. Geosynthetic reinforcements are particularly helpful for rigid pile solutions in high embankments due to their load transfer capability. Additionally, physical properties of fill soil can impact the inclusion solutions, with high shear resistance enhancing the arching effect and lower modulus subsoils showing better arching performance.","PeriodicalId":505610,"journal":{"name":"Geotechnics","volume":"8 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-11-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139245221","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0