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Investigations on pullout behavior of geogrid-granular trench using CANAsand constitutive model

Journal of Rock Mechanics and Geotechnical Engineering 2017年第4期9卷 726-740页

作者： ali noorzad Ehsan Badakhshan Faculty of Civil Water and Environmental Engineering Shahid Beheshti University Tehran Iran

Experimental and numerical investigations have been carried out on behavior of pullout resistance of embedded circular plate with and without geogrid reinforcement layers in stabilized loose and dense sands using a granular *** parameters have been considered,such as the number of geogrid layers,embedment depth ratio,relative density of soil and height ratio of granular *** showed that,without granular trench,the single layer of geogrid was more effective in enhancing the pullout capacity compared to the multilayer of geogrid ***,increasing the soil density and embedment depth ratio led to an increase in the uplift *** soil was improved with the granular trench,the uplift force significantly *** granular trench improved the uplift load in dense sand more,as compared to the same symmetrical plate embedded in loose *** it was observed that,in geogrid-reinforced granular trench condition,the ultimate pullout resistance at failure increased as the number of geogrid layers increased up to the third layer,and the fifth layer had a negligible effect in comparison with the third layer of *** element analyses with hardening soil model for sand and CANAsand constitutive model for granular trench were conducted to investigate the failure mechanism and the associated rupture surfaces *** response of granular material in the proposed model is an elastoplastic constitutive model derived from the CANAsand model,which uses a non-associated flow rule along with the concept of the state boundary surface possessing a critical and a compact *** was observed that the granular trench might change the failure mechanism from deep plate to shallow plate as the failure surface can extend to the ground *** ultimate uplift capacity of anchor and the variation of surface deformation indicated a close agreement between the experiment and numerical model.

关键词： Anchor Pullout test Geogrid Granular trench CANAsand constitutive model

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Seismic analysis of dam-foundation-reservoir system including the effects of foundation mass and radiation damping

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Earthquake Engineering and Engineering Vibration 2019年第1期18卷 203-218页

作者： Hamid Mohammadnezhad Mohsen Ghaemian ali noorzad Department of Civil Engineering Sharif University of Technology Faculty of Civil Water and Environmental Engineering Shahid Beheshti University

One of the main concerns in using commercial software for finite element analyses of dam-foundation-reservoir systems is that the simplifying assumptions of the massless foundation are unreliable. In this study, an appropriate direct finite element method is introduced for simulating the mass, radiation damping and wave propagation effect in foundations of damfoundation-reservoir systems using commercial software ABAQUS. The free-field boundary condition is used for modeling the semi-infinite foundation and radiation damping, which is not a built-in boundary condition in most of the available commercial software for finite element analysis of structures such as ANSYS or ABAQUS and thus needs to be implemented differently. The different mechanism for modeling of the foundation, earthquake input and far-field boundary condition is described. Implementation of the free-field boundary condition in finite element software is verified by comparing it with analytical results. To investigation the feasibility of the proposed method in dam-foundation-reservoir system analysis, a series of analyses is accomplished in a variety of cases and the obtained results are compared with the substructure method by using the EAGD-84 program. Finally, the massed and massless foundation results are compared and it is concluded that the massless foundation approach leads to the overestimation of the displacements and stresses within the dam body.

关键词： dam-foundation interaction radiation damping free-field boundary condition massed foundation

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Predicting crest settlement in concrete face rockfill dams using adaptive neuro-fuzzy inference system and gene expression programming intelligent methods

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2013年第8期14卷 589-602页

作者： Danial BEHNIA Kaveh AHANGARI ali noorzad Sayed Rahim MOEINOSSADAT Department of Mining Engineering Science and Research Branch Islamic Azad University Faculty of Water and Environmental Engineering Power and Water University of Technology

This paper deals with the estimation of crest settlement in a concrete face rockfill dam （CFRD）, utilizing intelligent methods. Following completion of dam construction, considerable movements of the crest and the body of the dam can develop during the first impoundment of the reservoir. Although there is vast experience worldwide in CFRD design and construction, few accurate experimental relationships are available to predict the settlement in CFRD. The goal is to advance the development of intelligent methods to estimate the subsidence of dams at the design stage. Due to dam zonifieation and uncertainties in material properties, these methods appear to be the appropriate choice. In this study, the crest settlement behavior of CFRDs is analyzed based on compiled data of 24 CFRDs constructed during recent years around the world, along with the utilization of gene ex- pression programming （GEP） and adaptive neuro-fuzzy inference system （ANFIS） methods. In addition, dam height （H）, shape factor （St）, and time （t, time after first operation） are also assessed, being considered major factors in predicting the settlement behavior. From the relationships proposed, the values ofR2 for both equations of GEP （with and without constant） were 0.9603 and 0.9734, and for the three approaches of ANFIS （grid partitioning （GP）, subtractive clustering method （SCM）, and fuzzy c-means clustering （FCM）） were 0.9693, 0.8657, and 0.8848, respectively. The obtained results indicate that the overall behavior evaluated by this approach is consistent with the measured data of other CFRDs.

关键词： Concrete face rockfill dam (CFRD) Crest settlement Adaptive neuro-fuzzy inference system (ANFIS) Geneexpression programming (GEP)

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Load eccentricity effects on behavior of circular footings reinforced with geogrid sheets

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Journal of Rock Mechanics and Geotechnical Engineering 2015年第6期7卷 691-699页

作者： Ehsan Badakhshan ali noorzad Faculty of Civil Water & Environmental EngineeringShahid Beheshti University

In this paper, an experimental study for an eccentrically loaded circular footing, resting on a geogridreinforced sand bed, is performed. To achieve this aim, the steel model footing of 120 mm in diameterand sand in relative density of 60% are used. Also, the effects of depth of first and second geogrid layersand number of reinforcement layers （1e4） on the settlement-load response and tilt of footing undervarious load eccentricities （0 cm, 0.75 cm, 1.5 cm, 2.25 cm and 3 cm） are investigated. Test results indicatethat ultimate bearing capacity increases in comparison with unreinforced condition. It is observed thatwhen the reinforcements are placed in the optimum embedment depth （u/D ？0.42 and h/D ？0.42）, thebearing capacity ratio （BCR） increases with increasing load eccentricity to the core boundary of footing,and that with further increase of load eccentricity, the BCR decreases. Besides, the tilt of footing increaseslinearly with increasing settlement. Finally, by reinforcing the sand bed, the tilt of footing decreases at 2layers of reinforcement and then increases by increasing the number of reinforcement layers.

关键词： Model test Circular footing Eccentric load Reinforced sand Bearing capacity

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A worldwide SPT-based soil liquefaction triggering analysis utilizing gene expression programming and Bayesian probabilistic method

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Journal of Rock Mechanics and Geotechnical Engineering 2017年第4期9卷 683-693页

作者： Maral Goharzay ali noorzad Ahmadreza Mahboubi Ardakani Mostafa Jalal Faculty of Civil Water and Environmental EngineeringShahid Beheshti University Zachry Department of Civil Engineering Texas A & M UniversityCollege Station

In this context,two different approaches of soil liquefaction evaluation using a soft computing technique based on the worldwide standard penetration test(SPT) databases have been *** expression programming(GEP) as a gray-box modeling approach is used to develop different deterministic models in order to evaluate the occurrence of soil liquefaction in terms of liquefaction field performance indicator(LI) and factor of safety(FS) in logistic regression and classification *** comparative plots illustrate that the classification concept-based models show a better performance than those based on logistic *** the probabilistic approach,a calibrated mapping function is developed in the context of Bayes’ theorem in order to capture the failure probabilities(PL) in the absence of the knowledge of parameter *** results obtained from the proposed probabilistic models,compared to the most well-known models,indicate the robustness of the methodology used in this *** probability models provide a simple,but also efficient decision-making tool in engineering design to quantitatively assess the liquefaction triggering thresholds.

关键词： Liquefaction Soft computing technique Gene expression programming(GEP) Deterministic model Bayes' theorem

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包裹式土工格栅-砂土相互作用对条形基础承载力-沉降特性的影响研究

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岩土力学 2022年第9期43卷 2550-2567页

作者： AHMAD Hussein MAHBOUBI Ahmad noorzad ali HOSEINI Mohammad Hosein 蒂什林大学土木工程学院岩土工程学系拉塔基亚叙利亚沙希德·贝赫什提大学土木、水和环境工程学院德黑兰伊朗

高质量材料的使用以及土层的处理是保持建筑结构稳定并保证其设计寿命的重要因素,尤其是在垫层较差的地区。对未加筋、土工格栅加筋和折叠土工格栅加筋细砂上方的条形基础进行试验研究,以评估平面土工格栅层数、折叠土工格栅在土中的位... 详细信息

高质量材料的使用以及土层的处理是保持建筑结构稳定并保证其设计寿命的重要因素,尤其是在垫层较差的地区。对未加筋、土工格栅加筋和折叠土工格栅加筋细砂上方的条形基础进行试验研究,以评估平面土工格栅层数、折叠土工格栅在土中的位置、土工格栅折叠层的厚度、折叠土工格栅的搭接长度、土工格栅折叠层的间距以及土工格栅的层数等因素的影响。与平面土工格栅加筋砂相比,折叠土工格栅加筋砂在静载作用下的性能更好。此外,在基础下方一定深度处存在一个临界区域。在该区域内,折叠土工格栅会导致基础沉降量增加。这一临界区域会影响较小基础宽度处的砂土特性。试验结果表明,折叠土工格栅的最优埋置深度为基础宽度的0.41,厚度为基础宽度的0.20。增加折叠土工格栅的层数可以明显减少沉降比。该试验表明,包裹式加筋可以显著提高结构框架的承载能力,减少沉降,并使得它们可以在狭小的空间中使用。

关键词：土工合成材料条形基础包裹式土工格栅平面土工格栅砂土承载力沉降特性

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The Effect of Alluvial Foundation on the Earth Dams Settlement

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Open Journal of Geology 2017年第3期7卷 360-373页

作者： Masoud Ghaemi Kaveh Ahangari ali noorzad Kamran Goshtasbi Department of Mining Engineering Science and Research Branch Islamic Azad University Tehran Iran Faculty of Water and Environmental Engineering Shahid Beheshti University Tehran Iran Faculty of Mining Engineering Tarbiat Modares University Tehran Iran

Careful monitoring in the earth dams, to measure deformation caused by settlement and movement has always been a concern for engineers in the field. In order to measure settlement and deformation of earth dams, usually the precision instruments of settlement set and combined Inclinometer that is commonly referred to IS instrument, will be used. In some dams, because the thickness of alluvium is high and there is no possibility of alluvium removal (technically and economically and in terms of performance), there is no possibility to place the end of IS instrument (precision instruments of Inclinometer-settlement set) in the rock foundation. Inevitably, have to accept installing pipes in the weak and the deformable alluvial foundation that this leads to errors in the calculation of the actual settlement (absolute settlement) in different parts of the dam body. The purpose of this paper is to present new and refine criteria for predicting settlement and deformation in earth dams. The study is based on conditions in three dams with a deformation quite alluvial (Agh Chai, Narmashir and Gilan-e Gharb) to provide settlement criteria affected by alluvial foundation. To achieve this goal, the settlement of dams was simulated by using finite difference method with FLAC3D software and then the modeling results were compared with reading IS instrument. In the end, the caliber of the model and validate the results, by using regression analysis techniques and scrutinized modeling parameters with real situations and then by using MATLAB software and Curve Fitting Toolbox, a new criteria for the settlement based on elasticity modulus, cohesion, friction angle, density of earth dam and alluvial foundation was obtained. The results of these studies show that, by using the new criteria measures, the amount of settlement and deformation for the dams with alluvial foundation can be corrected after instrument readings and the error rate in reading IS instrument can be greatly reduced.

关键词： Earth Dam Alluvial Foundation Settlement Finite Difference FLAC3D MATLAB Curve Fitting Refine Criteria IS Instrument

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