Soils and Foundations最新文献

{"title":"Energy-based insight into characterization of shakedown behavior of fully weathered red mudstone","authors":"Kang Chen ,&nbsp;Shengyang Yuan ,&nbsp;Shenxin Pan ,&nbsp;Jie Ma ,&nbsp;Xianfeng Liu","doi":"10.1016/j.sandf.2023.101360","DOIUrl":"https://doi.org/10.1016/j.sandf.2023.101360","url":null,"abstract":"<div><p>Weathered Red mudstone is widely distributed in Sichuan basin. The compacted weathered red mudstone has been used as subgrade fill materials of high-speed railway in southwestern of China. Dynamic responses of such materials under cyclic loading are critical to long-term stability of subgrade. Shakedown concept is widely employed in characterizing the permanent deformation behavior of soils. According to the evolution of axial strain (Werkmeister’s theory) or unit dissipated energy (Tao’s theory) with loading cycles, the behavior of unbound granular materials can be classified into three categories: plastic shakedown, plastic creep and incremental collapse. However, both theories are more suitable for the unbound granular materials with some limitations when used to separate the plastic creep and incremental collapse behavior. To overcome the limitations of the current theories, 26 cyclic triaxial tests were conducted on a saturated fully weathered red mudstone (SFWRM) to study the evolution of axial strain and unit dissipated energy during cyclic loading. A clear dependency of axial strain, axial strain rate on the unit dissipated energy level under various cyclic stress states were observed. A new criterion which is based on the responses of unit dissipated energy with cyclic stress ratio, was proposed to determine the limit between plastic creep and incremental collapse. Comparing with Werkmeister’s criterion and Tao’s criterion, the proposed criterion showed a better performance in identifying the incremental collapse behavior of the SFWRM.</p></div>","PeriodicalId":21857,"journal":{"name":"Soils and Foundations","volume":null,"pages":null},"PeriodicalIF":3.7,"publicationDate":"2023-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49744288","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}

{"title":"Excavation analysis of large-scale slope considering effects of folded structure and in-situ stress","authors":"Kaixuan YUAN ,&nbsp;Yuusuke MIYAZAKI ,&nbsp;Wataru KUNIMATSU ,&nbsp;Kohei MIKI ,&nbsp;Tomihiko OHISHI ,&nbsp;Kiyoshi KISHIDA","doi":"10.1016/j.sandf.2023.101373","DOIUrl":"https://doi.org/10.1016/j.sandf.2023.101373","url":null,"abstract":"<div><p>A cut slope in Rajamandala, Indonesia exhibited unexpected large-scale deformation during the excavation process which was revealed by the clinometers attached to the preventive piles. A geological survey indicated that the mudstone layer composing the slope had been folded by tectonic movement and was highly weathered and eroded at the surface. The above internal factors could have resulted in the significant deformation of the slope, although few studies have focused on the influence of folded structures and horizontal in-situ stress on the deformation behavior of cut slopes. Therefore, the objective of this paper is to clarify the influence of the folded structure and anisotropic in-situ stress state induced by tectonic movement on the deformation behavior of the aforementioned cut slope. To achieve this clarification, numerical analyses were performed based on the explicit finite difference method included in the FLAC2D software using different geological structures and in-situ stress states. Consequently, it was revealed that such folded structures can lead to larger displacement in cut slopes when compressive stress concentration occurs at the bottom of the fold. Moreover, an anisotropic in-situ stress state can result in shear failure at the foot of the mudstone and reproduce the displacement of piles that possess shapes as close as possible to those observed at the site. These analytical results confirmed that the folded structure and anisotropic in-situ stress state were the inevitable factors in the large deformation of the cut slope in Rajamandala, Indonesia.</p></div>","PeriodicalId":21857,"journal":{"name":"Soils and Foundations","volume":null,"pages":null},"PeriodicalIF":3.7,"publicationDate":"2023-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49744066","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}

{"title":"Foreword – Special issue on the 3rd International Symposium on Risk Assessment and Sustainable Stability Design of Slopes – ISRSS-Sendai 2022","authors":"Feng Zhang,&nbsp;Shuji Moriguchi,&nbsp;Kazuhide Sawada,&nbsp;Guanlin Ye","doi":"10.1016/j.sandf.2023.101377","DOIUrl":"https://doi.org/10.1016/j.sandf.2023.101377","url":null,"abstract":"","PeriodicalId":21857,"journal":{"name":"Soils and Foundations","volume":null,"pages":null},"PeriodicalIF":3.7,"publicationDate":"2023-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49744169","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}

{"title":"Effects of stabilizers on CO2 fixation capacity in neutralization of alkali construction sludge","authors":"Su Myat Mon ,&nbsp;Aya Sakaguchi ,&nbsp;Shovon Raihan ,&nbsp;Nguyen Duc Trung ,&nbsp;Kimitoshi Hayano","doi":"10.1016/j.sandf.2023.101358","DOIUrl":"https://doi.org/10.1016/j.sandf.2023.101358","url":null,"abstract":"<div><p>Construction sludge, generated from tunneling and piling, is typically in a liquid state. It can be improved via physical treatments, such as dehydration, and/or chemical treatments, using stabilizers, in order to to be recycled as construction material. To adjust the strength of sludge, chemical treatments are often preferred. However, chemical treatments frequently result in alkali leaching. Methods to reduce alkalinity by curing the alkaline sludge under CO₂ gas at a certain concentration have been proposed in Japan. In recent years, technologies that utilize CO₂ to improve the quality of cementitious material have received considerable attention in terms of carbon capture. Therefore, the effects of stabilizers on the CO₂ fixation capacity of alkaline sludge during pH neutralization were investigated in this study. Accelerated carbonation and carbonate content measurement tests were conducted to detect the CO₂ content fixed in alkaline sludge specimens treated with various stabilizers. The test results showed that the fixed maximum CO₂ content per gram of dry mass of sludge, (<em>m</em>_CO2)^max, increased with the calcium oxide (CaO) content of the stabilizer(s) per gram of dry sludge, <em>C</em>_CaO. However, the rate of increase in (<em>m</em>_CO2)^max with <em>C</em>_CaO was significantly affected by the type of stabilizer used. In the case of quicklime (QL), the ratio of (<em>m</em>_CO2)^max to <em>C</em>_CaO was approximately 0.5, whereas, in the cases of fly ash (FA) and steel slag (SS), the ratio was approximately 0.25. The ratios for biomass ash and paper sludge ash were between that for QL and that for FA and SS. Detailed analyses of the test results suggest that the CaO content per gram of stabilizer(s) in the sludge, <em>C</em>*_CaO, can provide an estimate of the fixed maximum amount of CO₂ per gram of stabilizer(s) in the sludge, (<em>m*</em>_CO2)^max. However, other factors, including the amount of water-soluble Ca, should be considered for a precise evaluation. Additionally, the experimental results showed that the decrease in pH owing to neutralization increases with the increasing <em>C</em>_CaO. However, the type of stabilizer did not significantly affect the relationship between the degree of CO₂ fixation and the degree of neutralization.</p></div>","PeriodicalId":21857,"journal":{"name":"Soils and Foundations","volume":null,"pages":null},"PeriodicalIF":3.7,"publicationDate":"2023-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49763920","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}

{"title":"Experimental investigation into effects of lignin on sandy loess","authors":"Gaochao Lin ,&nbsp;Wei Liu ,&nbsp;Jixiang Zhao ,&nbsp;Pengchao Fu","doi":"10.1016/j.sandf.2023.101359","DOIUrl":"https://doi.org/10.1016/j.sandf.2023.101359","url":null,"abstract":"<div><p>Promoted by the international Helin Airplane project where sandy loess is widely distributed, this study investigates the feasibility of improving the mechanical properties of sandy loess by using lignin, an environmentally friendly material. Considering the climatic conditions in the distribution area of sandy loess, such as strong evaporation and large diurnal temperature difference, extensive experiments including curing test, wet-dry cycle test, freeze–thaw cycle test, triaxial test, XRD test and SEM test are conducted to determine the strengthening effect of lignin on sandy loess. Test results show that 21 days are enough for lignin-modified sandy loess to complete curing and obtain maximum compressive strength, which increases with the increase of lignin content. Lignin has insignificant effect on the resistance of sandy loess to wet-dry cycles, but it can significantly improve the resistance to freeze–thaw cycles. Lignin causes significant alterations on the stress–strain relationship and mechanical response of sandy loess by mainly changing the cohesion while maintaining the frictional angle unchanged. SEM results show that lignin gradually plays the role of cementation, bonding, and fiber reinforcement with increasing content, and it mainly affects fine-grained soils while it has less effect on large particles. Good agreement between different experiments is obtained.</p></div>","PeriodicalId":21857,"journal":{"name":"Soils and Foundations","volume":null,"pages":null},"PeriodicalIF":3.7,"publicationDate":"2023-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49743958","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}

{"title":"Mechanism of sampling disturbance for peat ground and its influence on mechanical properties","authors":"Nobutaka Yamazoe ,&nbsp;Hiroyuki Tanaka ,&nbsp;Toshihiro Ogino ,&nbsp;Satoshi Nishimura","doi":"10.1016/j.sandf.2023.101361","DOIUrl":"https://doi.org/10.1016/j.sandf.2023.101361","url":null,"abstract":"<div><p>A soil investigation was conducted in peatlands in Japan, using two types of tube sampling methods, and the quality of the samples was evaluated. Unlike clays, peats easily lose water by compressive actions involved in sampler intrusion and core extrusion, leading to a significant loss of pore water. It was shown that this effect could be minimized by careful thin-wall sampling with a stationary piston, whereas open-drive sampling without a piston led to the significant compression of the sample core. The consequence of this disturbance on the in-situ behavior was interpreted through an examination of the mechanical properties of peat samples subjected to the “strain paths” expected during sampling in laboratory tests. By observing the deformation characteristics through a series of constant-rate-of-strain consolidation, unconfined compression, triaxial compression, and bender element tests, it was demonstrated that, contrary to soft clays, fibrous peats with high initial permeability potentially lead to the underestimation of the settlement during construction and the overestimation of strength due to inappropriate sampling. These results can be explained by the dominance of densification by disturbance over soil structure degradation. It was also noted that the sample quality varied considerably within the sampling tube.</p></div>","PeriodicalId":21857,"journal":{"name":"Soils and Foundations","volume":null,"pages":null},"PeriodicalIF":3.7,"publicationDate":"2023-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49744165","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}

{"title":"Analysis of long-term settlement of road embankment on peat ground during its service period","authors":"Nobutaka Yamazoe ,&nbsp;Hiroyuki Tanaka ,&nbsp;Satoshi Nishimura ,&nbsp;Hirochika Hayashi","doi":"10.1016/j.sandf.2023.101362","DOIUrl":"https://doi.org/10.1016/j.sandf.2023.101362","url":null,"abstract":"<div><p>Roads on peat grounds are subject to stringent requirements in terms of controlling the residual settlement during their service period in order to minimize the post-construction maintenance work. This paper addresses the applicability of the Finite Element Method (FEM) by incorporating a time-dependent model for peats to an evaluation of the residual settlement. The applicability of isotach viscoplasticity, used to describe the peats’ behavior under variable-rate compression, was confirmed in laboratory tests. Long-term consolidation test results and a model simulation revealed the particular importance of two mechanisms in the residual settlement in peat grounds, namely, the stress-dependency of the coefficient of consolidation, <em>c</em>_v, and the viscosity-induced secondary consolidation. A model peat ground, capturing these mechanisms, was implemented for the FEM and applied to a case history of a high-standard road construction in Hokkaido, Japan. The viscoplastic parameters determined from standard oedometer tests successfully reproduced the observed long-term settlement in a peat-dominated section of the expressway. The analysis was extended to address the settlement in the peat ground with the installation of prefabricated vertical drains (PVDs). The results indicate that the delayed primary consolidation due to the stress-induced <em>c</em>_v reduction can be significantly alleviated, while the settlement arising from the secondary consolidation over a longer term is little affected by the PVDs. These insights point to the importance of untangling the two mechanisms of long-term settlement for the sake of making accurate predictions of the residual settlement in different time scales.</p></div>","PeriodicalId":21857,"journal":{"name":"Soils and Foundations","volume":null,"pages":null},"PeriodicalIF":3.7,"publicationDate":"2023-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49744192","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}

{"title":"Effects of seepage flow on liquefaction resistance of uniform sand and gap-graded soil under undrained cyclic torsional shear","authors":"Sanjei Chitravel ,&nbsp;Masahide Otsubo ,&nbsp;Reiko Kuwano","doi":"10.1016/j.sandf.2023.101363","DOIUrl":"https://doi.org/10.1016/j.sandf.2023.101363","url":null,"abstract":"<div><p>Internal erosion is the transportation of soil particles from within or beneath geotechnical structures, caused by seepage flow, that impacts the subsequent mechanical and hydraulic behaviour of the soil. However, it is difficult to predict the liquefaction resistance of eroded soil due to several factors related to the soil fabric. The present study investigates the impact of seepage flow on the undrained cyclic behaviour of two types of soil: uniform sand and gap-graded soil with a fines content of 20%, using a novel erosion hollow cylindrical torsion shear apparatus. From the results for the uniform sand, the soil fabric formed by moist tamping (MT) leads to higher liquefaction resistance than that formed by air-pluviation (AP). However, after applying seepage flow, the liquefaction resistance of the eroded MT specimens becomes even lower than that of the non-eroded AP specimen. Therefore, the liquefaction resistance of soil is expected to decrease due to the rearrangement of the initially stable coarse particles during seepage flow. On the other hand, the liquefaction resistance of the gap-graded soil tends to increase after the removal of fines as the number of stable contacts between the coarse particles is increased. Under these test conditions, the latter effect is found to be greater for the given gradation, leading to a slight increase in the liquefaction resistance of the tested gap-graded soil after internal erosion. Furthermore, the intergranular void ratio and small-strain shear modulus are seen to be well correlated with the liquefaction resistance of the tested soil.</p></div>","PeriodicalId":21857,"journal":{"name":"Soils and Foundations","volume":null,"pages":null},"PeriodicalIF":3.7,"publicationDate":"2023-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49743540","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}

{"title":"A simple continuum approach to predict the drained pull-out response of piles for offshore wind turbines","authors":"Riccardo Zabatta ,&nbsp;Laura Govoni ,&nbsp;Aligi Foglia ,&nbsp;Alessio Mentani","doi":"10.1016/j.sandf.2023.101376","DOIUrl":"https://doi.org/10.1016/j.sandf.2023.101376","url":null,"abstract":"<div><p>The article presents a continuum approach to predict the response of pile foundations for jacket-supported offshore wind turbines. Tensile loading conditions are examined, which may be critical for piles used in combination with this structure type, generally adopted to exploit wind energy in intermediate water depths. The approach is developed to guarantee a simple implementation with a limited number of input data easily attainable from cone penetration tests and laboratory tests, and to ensure computational cost-effectiveness. Data from technical-scale tests on open-ended steel piles driven in dense sand and subjected to drained pull-out are used to assess the performance of the approach. The results are shown to be accurate, approximating rather closely the experimental load–displacement curves. The accuracy of the approach is also compared to that obtained with a recently proposed design method, to investigate the predictive capacity of the approach and its potential to support preliminary design activities.</p></div>","PeriodicalId":21857,"journal":{"name":"Soils and Foundations","volume":null,"pages":null},"PeriodicalIF":3.7,"publicationDate":"2023-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49746998","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}

{"title":"Primary and secondary consolidation characteristics of a high plasticity overconsolidated clay in compression and swelling","authors":"Emil Mejlhede Kinslev ,&nbsp;Ole Hededal ,&nbsp;Irene Rocchi ,&nbsp;Varvara Zania","doi":"10.1016/j.sandf.2023.101375","DOIUrl":"https://doi.org/10.1016/j.sandf.2023.101375","url":null,"abstract":"<div><p>For a reliable prediction of the time-development of soil deformations, a detailed characterization of both primary and secondary deformations is required. Nevertheless, in the current engineering practice the estimation of the primary and secondary deformations relies on the assumption of a constant coefficient of consolidation and a constant creep index respectively. However, high plasticity overconsolidated clays have reportedly complex stiffness and permeability relationships that challenge the validity of those assumptions. Analytical solutions of the one dimensional consolidation have been proposed, accounting for variation in permeability and oedometer modulus. Nevertheless, the methods assume a simplified log-linear and linear relationship with void ratio and effective stress for the two parameters, respectively. One-dimensional oedometer and constant rate of strain testing were employed to investigate the time-deformation development of a particular high plasticity overconsolidated clay. A dependency of the time until the end of primary deformations on the stress path was observed, with the majority of the unloading steps extending well beyond the 24 h typical duration of a load increment. It was revealed that the coefficient of consolidation generally increases during consolidation, and it may vary by more than one order of magnitude at the early stages of the consolidation process. This variation has been attributed to a transient effect noticed in the permeability, which has not been previously reported. The linear relationship between primary and secondary deformation indices was confirmed as an upper bound. In an effort to better characterize the time dependent behaviour a new index, the primary time deformation index, was defined as the slope at the inflection point of the time-curves. This parameter was found to be linearly related to the creep index, presenting thus a potential of better predictions of the duration and magnitude of consolidation deformations for the engineering practice.</p></div>","PeriodicalId":21857,"journal":{"name":"Soils and Foundations","volume":null,"pages":null},"PeriodicalIF":3.7,"publicationDate":"2023-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49746996","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}