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The Influence of Rockfill Material's Particle Breakage on Long-Term Time-Dependent Settlement of Embankment dams 堆石料颗粒破碎对路堤坝长期随时间沉降的影响
IF 2.2 4区 工程技术 Q2 Earth and Planetary Sciences Pub Date : 2022-01-31 DOI: 10.1680/jgeen.21.00005
Saber Alidadi, R. Alipour, M. Shakeri
The current research was implemented to monitor and rehabilitate the structural health of Masjed-E-Soleyman, M.E.S., dam with 177 m height, one of the highest Iranian rockfill dams. This dam suffers from extensive and unpredictable settlements and related cracks. In order to investigate the nonhomogeneous (Conglomerate) rockfill's brittle behavior in Before-After and During the triaxial tests, a series of laboratory tests in conventional stress paths were carried out using a large-scale triaxial apparatus. A numerical time-dependent model was introduced inside the laboratory tests to find a relationship between particle breakage and the time-dependent settlement of the embankment dam. The core of this paper aimed to investigate the particle breakage of Conglomerate material in the M.E.S. dam and to modify the nonhomogeneous relative particle breakage index, by establishing a relationship between relative particle breakage index for this material and the plastic work. The conclusions of this research were categorized into three significant steps. The Breakage Index (Before-After tests) was calculated in the first step. Secondly, a relationship between Breakage Index and plastic work (During tests) was introduced. Finally, a predictable pattern of dam's crest settlement was presented using numerical Viscoelastic Burgers model and its calibration with accurate monitoring data of the M.E.S. dam.
目前的研究是为了监测和恢复Masjed-E-Soleyman, m.e.s.大坝的结构健康,该大坝高177米,是伊朗最高的堆石坝之一。这座大坝受到广泛和不可预测的沉降和相关裂缝的影响。为了研究非均质(砾岩)堆石料在三轴试验前后和试验过程中的脆性行为,采用大型三轴试验装置,在常规应力路径下进行了一系列室内试验。在室内试验中引入了一个随时间变化的数值模型,以寻找颗粒破碎与堤防坝随时间变化的沉降关系。本文的核心是通过建立砾岩材料的相对颗粒破碎指数与塑性功之间的关系,研究砾岩材料在M.E.S.坝中的颗粒破碎情况,修正非均匀相对颗粒破碎指数。本研究的结论分为三个重要步骤。第一步计算破损指数(前后试验)。其次,介绍了断裂指数与塑性功(试验期间)的关系。最后,利用数值粘弹性Burgers模型,给出了坝顶沉降的预测模式,并与M.E.S.大坝的精确监测数据进行了标定。
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引用次数: 3
Observed Responses of a Saturated Sand under Constant Deviatoric Stress Path in Drained Triaxial tests over a Range of Applied Shear Stress 恒定偏应力路径下排水三轴试验饱和砂土在施加剪切应力范围内的响应观察
IF 2.2 4区 工程技术 Q2 Earth and Planetary Sciences Pub Date : 2022-01-31 DOI: 10.1680/jgeen.21.00086
Zhiyi Zhao, Yanli Dong, Zhaopeng Zhang, Ying Gao, Xiaoshuang Zhang
The soil in embankment dams and slopes may accumulate irreversible deformation due to variation of water level. During that process, soil skeleton experiences constant deviatoric stress path, along with cyclic mean effective stress. In this work, triaxial drained tests were conducted under low rate of strain on saturated sand to investigate the strain response along such stress path, considering the influence of loading amplitude. Test results demonstrated that volumetric strain of saturated sand was diverse, when the consolidation stress conditions were different. When consolidation deviatoric stress was increased from 300 kPa to 900 kPa, the effect of amplitude of cyclic on the volumetric strain is strengthened, while the cumulative effect is weakened. The shear strain curves under different loading amplitudes were parallel to each other, no matter what the consolidation stress condition was. However, the cumulative shear strain showed great differences. Motivated by the effect of loading amplitude, the accumulation of shear strain was increased. While the consolidation deviatoric stress was held constant at a low stress level, the effect of loading amplitude on volumetric strain was greater than that on shear strain. However, with the enhancement of stress level, the effect on shear strain would be significantly enhanced.
由于水位的变化,堤防、坝体和边坡中的土体会发生不可逆变形。在此过程中,土骨架经历了恒定的偏应力路径,并伴随着循环平均有效应力。本文在饱和砂土上进行了低应变速率下的三轴排水试验,考虑加载幅值的影响,研究了该应力路径下的应变响应。试验结果表明,在固结应力条件不同的情况下,饱和砂土的体积应变是不同的。当固结偏应力从300 kPa增加到900 kPa时,循环幅值对体应变的影响增强,累积效应减弱。无论固结应力条件如何,不同加载幅值下的剪切应变曲线都是平行的。但累积剪切应变差异较大。受加载幅值的影响,剪切应变的累积量增大。在低应力水平下固结偏应力保持不变时,加载幅值对体应变的影响大于对剪切应变的影响。但随着应力水平的提高,对剪切应变的影响会显著增强。
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引用次数: 0
Resistance and Swellability of Stabilized Samples of Marl Problematic Soils Using Nano-silica and Nano-alumina 用纳米二氧化硅和纳米氧化铝稳定泥灰岩问题土样品的阻力和膨胀性
IF 2.2 4区 工程技术 Q2 Earth and Planetary Sciences Pub Date : 2022-01-31 DOI: 10.1680/jgeen.21.00016
R. Alipour, Heshmati R. Ali Akbar, Jafar Karimiazar, Narges Isazadehfar, E. Asghari-Kaljahi, S. H. Bahmani
This study investigates the effects of Nano-silica and Nano-alumina on the Marl soil as a problematic soil in Tabriz, Iran. These soils, which are among the swellable soils, constitute the foundation of most projects in Tabriz. Due to water absorption, these soils are liable to volume change and instability risks in the foundation of projects. Consequently, various physical and chemical methods have been employed to stabilize these soils. In the present study, for the first time, the reconstructed samples of Tabriz Marl were stabilized with various percentages of Nano-silica and Nano-alumina, which have fewer environmental effects in comparison with ordinary additives such as Portland cement or lime. In addition, soil swelling behaviors have been evaluated by various experiments including Atterberg limits, density, free swelling, swelling pressure, California Bearing Ratio (CBR) tests, direct shear tests, Field Emission Scanning Electron Microscopy (FESEM), and X-ray powder diffraction (XRD) analyses which were conducted at 1, 7, and 28 days of curing times. The results show that Nano-alumina has a greater effect on reducing the swelling of stabilized samples than Nano-silica. However, the effect of Nano-silica has been more than Nano-alumina on increasing the strength CBR.
本研究调查了纳米二氧化硅和纳米氧化铝对伊朗大不里士灰泥土的影响。这些土壤属于可膨胀土壤,构成了大不里士大多数项目的基础。由于吸水,这些土壤在工程基础中容易发生体积变化和失稳风险。因此,人们采用了各种物理和化学方法来稳定这些土壤。在本研究中,首次使用不同百分比的纳米二氧化硅和纳米氧化铝来稳定大不里士泥的重建样品,与普通添加剂(如波特兰水泥或石灰)相比,纳米二氧化硅和纳米氧化铝对环境的影响更小。此外,通过各种实验,包括阿特伯格极限、密度、自由膨胀、膨胀压力、加州承载比(CBR)试验、直接剪切试验、场发射扫描电镜(FESEM)和x射线粉末衍射(XRD)分析,对土的膨胀行为进行了评估,这些实验分别在固化1、7和28天进行。结果表明,纳米氧化铝比纳米二氧化硅对稳定样品的溶胀有更大的抑制作用。然而,纳米二氧化硅在提高CBR强度方面的作用大于纳米氧化铝。
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引用次数: 4
Influence of compaction on small-strain shear modulus of iron ore tailings 压实对铁矿尾矿小应变剪切模量的影响
IF 2.2 4区 工程技术 Q2 Earth and Planetary Sciences Pub Date : 2022-01-17 DOI: 10.1680/jgeen.21.00036
J. P. Silva, P. Cacciari, L. F. Ribeiro, M. Jefferies
Understanding the geotechnical properties of iron ore tailings is one of the biggest challenges that the mining industry currently faces. The brittle behaviour of these tailings has brought the importance of small strain stiffness to the geotechnical forefront. However, lack of knowledge and information about the behaviour of iron ore tailings still exists. This paper presents the results and analysis of a laboratory program that aimed to assess the small strain stiffness of tailings materials. These materials were produced during the iron ore treatment process. Bender elements were used to measure shear wave velocities and evaluate dynamic shear moduli at different effective stress levels resulting from isotropic consolidation tests. Three types of iron ore tailings were used: (1) flotation, (2) slimes, and (3) blended with different grain-size distributions. Reconstituted specimens were prepared at different densities (loose and dense conditions) to assess initial density effects (percent compaction) upon the shear modulus. The laboratory results were compared with empirical correlations with other soil types. Nevertheless, these equations were ineffective in representing tailings materials that contain large amounts of fines (slimes). The advantages and limitations of these equations are discussed, and a new empirical equation that includes the degree of compaction is suggested.
了解铁矿尾矿的岩土力学特性是目前矿业面临的最大挑战之一。这些尾矿的脆性特性使小应变刚度的重要性上升到岩土工程的前沿。然而,对铁矿尾矿特性的认识和信息仍然缺乏。本文介绍了尾矿材料小应变刚度试验程序的结果和分析。这些材料是在铁矿处理过程中产生的。本德尔单元用于测量剪切波速,并评估由各向同性固结试验产生的不同有效应力水平下的动态剪切模量。采用3种不同类型的铁矿尾矿:(1)浮选尾矿,(2)泥尾矿,(3)不同粒度分布的混配尾矿。在不同密度(松散和致密条件)下制备重建试样,以评估初始密度对剪切模量的影响(压实百分比)。将实验室结果与其他土壤类型的经验相关性进行了比较。然而,这些方程对于含有大量细粒(泥)的尾矿材料是无效的。讨论了这些方程的优点和局限性,并提出了一个新的包含压实度的经验方程。
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引用次数: 1
On some uncertainties related to static liquefaction triggering assessments 关于静态液化触发评估的一些不确定因素
IF 2.2 4区 工程技术 Q2 Earth and Planetary Sciences Pub Date : 2022-01-05 DOI: 10.1680/jgeen.21.00054
D. Reid, Simon Dickinson, U. Mital, R. Fanni, A. Fourie
Static liquefaction has been identified as the cause of several recent tailings storage facility (TSF) failures. Partially based on the investigations carried out, significant advances on the analysis of static liquefaction triggering have been made. This includes application of critical state-based models in a stress-deformation framework to identify if in situ conditions are approaching a level where triggering could occur. However, several important uncertainties remain. The current work investigates three of these uncertainties and their effect (both independently, and in conjunction) on the identification of static liquefaction triggering and slope failure: geostatic stress ratio K0, intermediate principal stress ratio, and principal stress angle from vertical. These uncertainties are examined through a series of numerical analyses of an idealised TSF. Various values of K0 are used to examine their effect on triggering, while different approaches to the potential effect of intermediate principal stress ratio and principal stress angle from vertical on instability are taken. This work shows that current state of knowledge in these areas is such that significant uncertainty seems unavoidable in attempting to identify exactly when a particular slope may undergo static liquefaction triggering. Experimental and in situ test programs that may be useful in reducing this uncertainty are outlined.
静态液化已被确定为最近几起尾矿储存设施(TSF)故障的原因。部分基于所进行的研究,在静态液化触发分析方面取得了重大进展。这包括在应力变形框架中应用基于临界状态的模型,以确定原位条件是否接近可能发生触发的水平。然而,一些重要的不确定性仍然存在。目前的工作研究了这些不确定性中的三个及其对静态液化触发和边坡破坏识别的影响(包括独立的和联合的):地静应力比K0,中间主应力比和垂直方向的主应力角。通过对理想TSF的一系列数值分析来检验这些不确定性。利用不同的K0值考察了它们对触发的影响,并对中间主应力比和垂直方向主应力角对失稳的潜在影响采取了不同的方法。这项工作表明,目前在这些领域的知识状况是这样的,在试图准确确定特定斜坡何时可能经历静态液化触发时,显着的不确定性似乎是不可避免的。概述了可能有助于减少这种不确定性的实验和原位测试程序。
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引用次数: 4
Precise grading of surrounding rock based on the numerical calculation of the jointed rock mass 基于节理岩体数值计算的围岩精确分级
IF 2.2 4区 工程技术 Q2 Earth and Planetary Sciences Pub Date : 2022-01-05 DOI: 10.1680/jgeen.21.00155
Dan Huang, Xiao-qing Li, Wenfeng Song
In this study, grading of surrounding rock was based on rock mass basic quality (BQ) values according to the specifications in China. Numerical approach was to construct synthetic rock mass (SRM) model to represent the jointed rock mass, and obtain the strength of the rock mass. It represented intact rock by the bonded particle model (BPM), and represent joint behaviour by the smooth joint model (SJM) to construct the discrete fracture network (DFN). In the Hongtuzhang Tunnel, the micro properties of granite cores with different weathered degrees were determined by the validation process, and the calculation representative elementary volume (REV) of surrounding rock was 15 m×15 m. Five slightly weathered, three slightly to moderately weathered, and two moderately weathered granite surrounding rock mass models were established based on the probability distribution of joint sets in each borehole, the conversion BQ value was acquired according by the calculated strength of rock mass model. It was discussed the differences of surrounding rock grades between the geological survey method and the numerical calculation method, and then found that the geological survey report is higher than the numerical calculation method predicted. And the numerical calculation is consistent with the actual excavation of rock mass at borehole A1388.
在本研究中,根据中国规范的岩体基本质量(BQ)值对围岩进行分级。数值方法是建立综合岩体(SRM)模型来表示节理岩体,得到岩体的强度。用结合颗粒模型(BPM)表示完整岩石,用光滑节理模型(SJM)表示节理行为,构建离散裂缝网络(DFN)。在红土章隧道中,通过验证过程确定了不同风化程度花岗岩岩心的微观性质,计算得到围岩的代表性基本体积(REV)为15 m×15 m。根据各钻孔节理集的概率分布,建立了5个轻度风化、3个轻度至中度风化和2个中度风化花岗岩围岩模型,并根据计算得到的岩体模型强度获得转换BQ值。讨论了地质调查方法与数值计算方法在围岩品位上的差异,发现地质调查报告比数值计算方法预测的要高。数值计算结果与A1388钻孔岩体开挖实际吻合较好。
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引用次数: 1
An analytical model for predicting the shear strength of unsaturated soils 非饱和土抗剪强度预测的解析模型
IF 2.2 4区 工程技术 Q2 Earth and Planetary Sciences Pub Date : 2022-01-05 DOI: 10.1680/jgeen.21.00135
T. Pham, M. Sutman
The prediction of shear strength for unsaturated soils remains to be a significant challenge due to their complex multi-phase nature. In this paper, a review of prior experimental studies is firstly carried out to present important pieces of evidence, limitations, and some design considerations. Next, an overview of the existing shear strength equations is summarized with a brief discussion. Then, a micromechanical model with stress equilibrium conditions and multi-phase interaction considerations is presented to provide a new equation for predicting the shear strength of unsaturated soils. The validity of the proposed model is examined for several published shear strength data of different soil types. It is observed that the shear strength predicted by the analytical model is in good agreement with the experimental data, and get high performance compared to the existing models. The evaluation of the outcomes with two criteria, using average relative error and the normalized sum of squared error, proved the effectiveness and validity of the proposed equation. Using the proposed equation, the nonlinear relationship between shear strength, saturation degree, volumetric water content, and matric suction are observed.
由于非饱和土具有复杂的多相特性,其抗剪强度预测一直是一个重大挑战。在本文中,首先回顾了先前的实验研究,以提出重要的证据,局限性和一些设计考虑。接下来,对现有的抗剪强度方程进行概述和简要讨论。在此基础上,建立了考虑应力平衡条件和多相相互作用的细观力学模型,为非饱和土抗剪强度预测提供了新的公式。本文用几种已发表的不同土型抗剪强度数据验证了该模型的有效性。结果表明,分析模型预测的抗剪强度与试验数据吻合较好,与现有模型相比具有较高的性能。用平均相对误差和归一化误差平方和两个标准对结果进行评价,证明了所提方程的有效性和有效性。利用所提出的方程,观察了抗剪强度、饱和度、体积含水量和基质吸力之间的非线性关系。
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引用次数: 9
Stiffness matrix method for analysis of torsionally loaded piles in multi-layered soil 多层土中抗扭桩分析的刚度矩阵法
IF 2.2 4区 工程技术 Q2 Earth and Planetary Sciences Pub Date : 2021-12-08 DOI: 10.1680/jgeen.21.00140
C. A. Vega-Posada
A new, simple, and practical method to investigate the response of torsionally loaded piles on homogeneous or non-homogeneous multi-layered elastic soil is developed. The soil non-homogeneity is accounted for by assuming for each layer a shear modulus distribution that fits a quadratic function. The analysis of piles in multi-layered soil is carried out by subdividing the pile, at the soil-soil layer and soil-air interfaces, into multiple elements, and then using conventional matrix methods -such as those commonly implemented in structural analysis- to connect them. The governing differential equation (GDE) of an individual structural element is solved using the Differential Transformation Method (DTM). Next, the stiffness matrix is derived by applying compatibility conditions at the ends of the element. Piles partially or fully embedded in multiple layers and subjected to torsion can be analyzed in a simple manner with the proposed formulation -a tedious endeavor with other available solutions. Finally, explicit expressions for the coefficients of the matrix are provided. Four examples are presented to show the simplicity, accuracy, and capabilities of the proposed formulation.
提出了一种新的、简单实用的方法来研究均匀或非均匀多层弹性土上扭转荷载桩的响应。土的非均匀性是通过假设每一层的剪切模量分布符合二次函数来解释的。多层土中桩的分析是通过将桩在土-土层和土-气界面处细分为多个单元,然后使用传统的矩阵方法(如结构分析中常用的方法)将它们连接起来进行的。采用微分变换法求解了单个结构单元的控制微分方程。其次,通过在单元的两端应用相容性条件推导出刚度矩阵。部分或全部嵌入多层并受到扭转的桩可以用所提出的公式以简单的方式进行分析-与其他可用的解决方案相比,这是一项繁琐的工作。最后,给出了矩阵系数的显式表达式。给出了四个例子来说明所提出的公式的简单性、准确性和能力。
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引用次数: 1
Geostatic stress in oilsand tailings 油砂尾矿中的地静应力
IF 2.2 4区 工程技术 Q2 Earth and Planetary Sciences Pub Date : 2021-11-03 DOI: 10.1680/jgeen.21.00114
D. Shuttle, Scott Martens, M. Jefferies
{"title":"Geostatic stress in oilsand tailings","authors":"D. Shuttle, Scott Martens, M. Jefferies","doi":"10.1680/jgeen.21.00114","DOIUrl":"https://doi.org/10.1680/jgeen.21.00114","url":null,"abstract":"","PeriodicalId":54572,"journal":{"name":"Proceedings of the Institution of Civil Engineers-Geotechnical Engineering","volume":null,"pages":null},"PeriodicalIF":2.2,"publicationDate":"2021-11-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89961151","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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: 1
Discrete Element Modeling of Underground Tunnel Response to Reverse Fault Rupture in Sand 砂土中地下隧道逆断层破裂响应的离散元模拟
IF 2.2 4区 工程技术 Q2 Earth and Planetary Sciences Pub Date : 2021-10-18 DOI: 10.1680/jgeen.21.00134
Ronak Mehrabi, M. Baziar, A. Nabizadeh, W. Hung
{"title":"Discrete Element Modeling of Underground Tunnel Response to Reverse Fault Rupture in Sand","authors":"Ronak Mehrabi, M. Baziar, A. Nabizadeh, W. Hung","doi":"10.1680/jgeen.21.00134","DOIUrl":"https://doi.org/10.1680/jgeen.21.00134","url":null,"abstract":"","PeriodicalId":54572,"journal":{"name":"Proceedings of the Institution of Civil Engineers-Geotechnical Engineering","volume":null,"pages":null},"PeriodicalIF":2.2,"publicationDate":"2021-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85464128","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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
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Proceedings of the Institution of Civil Engineers-Geotechnical Engineering
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