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Predicting resilient modulus of recycled concrete and clay masonry blends for pavement applications using soft computing techniques

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Frontiers of Structural and Civil Engineering 2019年第6期13卷 1379-1392页

作者： Mosbeh R.KALOOP Alaa R.GABR Sherif M.EL-BADAWY Ali ARISHA Sayed SHWALLY Jong Wan HU Department of Civil and Environmental Engineering Incheon National UniversityIncheon 22012South Korea Incheon Disaster Prevention Research Center Incheon National UniversityIncheon 22012South Korea Department of Public Works and Civil Engineering Mansoura UniversityMansoura 35516Egypt

To date,very few researchers employed the Least Square Support Vector Machine(LSSVM)in predicting the resilient modulus(Mr)of Unbound Granular Materials(UGMs).This paper focused on the development of a LSSVM model to predict the MT of recycled materials for pavement applications and comparison with other different models such as Regression,and Artificial Neural Network(ANN).Blends of Recycled Concrete Aggregate(RCA)with Recycled Clay Masonry(RCM)with proportions of 100/0,90/10,80/20,70/30,55/45,40/60,20/80,and 0/100 by the total aggregate mass were evaluated for use as UGMs.RCA/RCM materials were collected from dumps on the sides of roads around Mansoura city,Egypt.The investigated blends were evaluated experimentally by routine and advanced tests and the Mr values were detennined by Repeated Load Triaxial Test(RLTT).Regression,ANN,and LSSVM models were utilized and compared in predicting the Mr of the investigated blends optimizing the best design model.Results showed that the Mx values of the investigated RCA/RCM blends were generally increased with the decrease in RCM proportion.Statistical analyses were utilized for evaluating the performance of the developed models and the inputs sensitivity parameters.Eventually,the results approved that the LSSVM model can be used as a novel tool to estimate the Mx of the investigated RCA/RCM blends.

关键词： Least Square Support Vector Machine Artificial Neural Network resilient modulus Recycled Concrete Aggregate Recycled Clay Masonry

High Pressure X-Ray Diffraction Study of a Grossular–Andradite Solid Solution and the Bulk modulus Variation along this Solid Solution

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Chinese Physics Letters 2011年第7期28卷 229-232页

作者：范大伟魏舒怡刘景李延春谢鸿森 Laboratory for Study of the Earth's Interior and Geofluids Institute of GeochemistryChinese Academy of SciencesGuiyang 550002 Institute of High Energy Physics Chinese Academy of SciencesBeijing 100049 Graduate University of the Chinese Academy of Sciences Beijing 100049

In-situ angle-dispersive x-ray diffraction measurements on three samples of Gr14An84,Gr34An64 and Gr63An34 were performed by using a diamond anvil cell instrument with synchrotron radiation at the Beijing Synchrotron Radiation Facility at up to 13.7 GPa.A least−square fit of the pressure-volume to the Birch–Murnaghan equation of state,when fixed K'0=4.0 yields bulk modulus values of K0=166±2,168±3,173±2 GPa for Gr_(14)An_(84),Gr_(34)An_(64 )and Gr_(63)An_(34),respectively.The bulk modulus increases from 166±2 GPa for Gr_(14)An_(84) and to 173±2 GPa for Gr_(63)An_(34) with the increasing An content.Furthermore,by linear interpolation,the bulk modulus of the Gr−An binary system as a function of An content can be expressed as K0(GPa)=176.9(9)−0.12(1)XAn(R^(2)=0.987).

关键词： modulus Solid Bulk

Simultaneous prediction of rock matrix modulus and critical porosity

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Applied Geophysics 2019年第1期16卷 14-24页

作者： Li Nuo Chen Hao Zhang Xiu-Mei Han Jian-Qiang Wang Jian Wang Xiu-Ming State Key Laboratory of Acoustics Institute of AcousticsChinese Academy of SciencesBeijing 100190China University of Chinese Academy of Sciences Beijing 100049China Beijing Engineering Research Center of sea deep drilling and exploration Beijing 100190China

The matrix modulus and critical porosity in rocks are two critical parameters to seismic rock physics models;however, the critical porosity is diffi cult to obtain. Based on the linear relation between the effective bulk modulus and porosity, we propose a fast method for calculating the matrix modulus and critical porosity by least square fi tting of effective bulk modulus and porosity data measured in laboratory or fi eld. The proposed method is well suited for samples with wide porosity range. The calculation results accurately refl ect the differences in clay content, pressure, and saturation state. Samples with high clay content have low matrix modulus and critical porosity. The matrix modulus is independent of pressure, whereas the critical porosity increases with increasing pressure. The calculated matrix modulus for watersaturated samples is higher than that for dry rock samples.

关键词： modulus porosity clay content pressure saturation

EXPERIMENTAL EVALUATION ON modulus OF EQUIVALENT HOMOGENEOUS ETTRINGITE

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Acta Mechanica Solida Sinica 2009年第4期22卷 320-327页

作者： Minghua Zhang Jiankang Chen Jue Zhu Jiangying Chen Department of Mechanics and Engineering Science Ningbo University Ningbo 315211 China

In the present study, the average modulus of delayed ettringite is evaluated by an experimental method combined with theoretical analysis. Firstly, the delayed ettringite crystal is synthesized by chemical reaction of Aluminum sulfate and calcium hydroxide. Secondly, specimens are obtained by compressing the delayed ettringite crystal under different pre-loads. Thirdly, the variation of the modulus of the specimen with different pre-loads is tested using Instron material test machine and the SHPB technique, respectively. It is found that the experimental data may be suitably fitted by Boltzmann Function. Finally, the porosity of the specimen is detected using the saturation method, and the effect of the porosity on the modulus is analyzed by the Eshelby＇s equivalent inclusion method and the Mori-Tanaka＇s scheme. The static and dynamic modulli of the equivalent homogeneous ettringite obtained in present study are approximately 10.64 GPa and 24.61 GPa, respectively.

关键词： ettringite equivalent homogeneous materials Boltzmann Function modulus

Settlement of composite foundation with discrete material pile considering modulus change

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Journal of Central South University 2008年第S2期15卷 8-14页

作者：曹文贵刘海涛李翔张永杰 Institute of Geotechnical Engineering Hunan University

Based on deeply discussing the deformation mechanism of composite foundation with discrete material pile, firstly, the settlement of composite foundation in rigid foundation conditions was assumed to consist of two parts, an expanding part and an un-expanding part. Then, in view of the differences of deformation properties between the expanding part and the un-expanding part, the relationships between the pile modulus and the applied load in these two parts were respectively developed. Thirdly, by introducing the above relationships into settlement analysis, a new method to calculate displacement of composite foundation with discrete material pile was proposed by using the multi-stage loading theory and the layer-wise summation approach. This method is effective not only for accounting for the effect of variations of pores on deformation modulus of the pile body in different depths, but also for describing the characteristics of different deformation mechanisms of the pile body with varying depth. Finally, the proposed method was used to a practical composite foundation problem, whose theoretical results were presented and compared to those of other methods. The rationality and feasibility of this method are identified through comparative analysis.

关键词： discrete material pile composite foundation settlement calculation pores deformation modulus

Random field characterization of uniaxial compressive strength and elastic modulus for intact rocks

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Geoscience Frontiers 2018年第6期9卷 1609-1618页

作者： Huaxin Liu Xiaohui Qi School of Civil and Environmental Engineering Nanyang Technological University

Rock properties exhibit spatial variabilities due to complex geological processes such as sedimentation,metamorphism, weathering, and tectogenesis. Although recognized as an important factor controlling the safety of geotechnical structures in rock engineering, the spatial variability of rock properties is rarely quantified. Hence, this study characterizes the autocorrelation structures and scales of fluctuation of two important parameters of intact rocks, i.e. uniaxial compressive strength(UCS) and elastic modulus(EM).UCS and EM data for sedimentary and igneous rocks are collected. The autocorrelation structures are selected using a Bayesian model class selection approach and the scales of fluctuation for these two parameters are estimated using a Bayesian updating method. The results show that the autocorrelation structures for UCS and EM could be best described by a single exponential autocorrelation function. The scales of fluctuation for UCS and EM respectively range from 0.3 m to 8.0 m and from 0.3 m to 8.4 m.These results serve as guidelines for selecting proper autocorrelation functions and autocorrelation distances for rock properties in reliability analyses and could also be used as prior information for quantifying the spatial variability of rock properties in a Bayesian framework.

关键词： Uniaxial compressive strength Elastic modulus Scale of fluctuation Autocorrelation function Spatial variability Bayesian approach

Cluster-formula-embedded machine learning for design of multicomponent β-Ti alloys with low Young’s modulus

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npj Computational Materials 2020年第1期6卷 824-834页

作者： Fei Yang Zhen Li Qing Wang Beibei Jiang Biaojie Yan Pengcheng Zhang Wei Xu Chuang Dong Peter K.Liaw Key Laboratory of Materials Modification by Laser Ion and Electron Beams(Ministry of Education)School of Materials Science and EngineeringDalian University of TechnologyDalian116024 LiaoningChina School of Mechanical Engineering Dalian University of TechnologyDalian116024 LiaoningChina Analysis and Test Center Guangdong University of TechnologyGuangzhou510006 GuangdongChina Institute of Materials China Academy of Engineering PhysicsJiangyou621908 SichuanChina State Key Laboratory of Rolling and Automation Northeastern UniversityShenyang110819 LiaoningChina Department of Materials Science and Engineering The University of TennesseeKnoxville37996 TNUSA

The present work formulated a materials design approach,a cluster-formula-embedded machine learning(ML)model,to search for body-centered-cubic(BCC)β-Ti alloys with low Young’s modulus(E)in the Ti–Mo–Nb–Zr–Sn–Ta system.The characteristic parameters,including the Mo equivalence and the cluster-formula approach,are implemented into the ML to ensure the accuracy of prediction,in which the former parameter represents the BCC-βstructural stability,and the latter reflects the interactions among elements expressed with a composition formula.Both auxiliary gradient-boosting regression tree and genetic algorithm methods were adopted to deal with the optimization problem in the ML model.

关键词： alloys modulus formula

Establishing time-dependent model of deformation modulus caused by bedrock excavation rebound by inverse analysis method

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Science China(Technological Sciences) 2008年第S2期51卷 1-7页

作者： WU ZhongRu1,2,GU YanChang1,3,GU ChongShi1,2,GUO HaiQing1 & SU HuaiZhi1,2 1 Hohai University,Nanjing 210098,China 2 National Engineering Research Center of Water Resources Efficient Utilization and Engineering Safety,Nanjing 210098,China 3 Nanjing Hydraulic Research Institute,Nanjing 210029,China Hohai University Nanjing China National Engineering Research Center of Water Resources Efficient Utilization and Engineering Safety Nanjing China Nanjing Hydraulic Research Institute Nanjing China

Rock rebound relaxation deformation,or even rock burst,caused by the excavation of dam base and abutment or high rock slope affects their stability and results in the fall of mechanical properties of the rock.So an inverse analysis method was proposed in this paper to establish the time-dependent model of deformation modulus caused by excavation rebound.The basic principle is based on the combination of observed data of the excavation rebound deformation of dam abutment or rock slope,and the calculated rebound deformation by FEM under ground stress at the corresponding time in the excavation process.The norm of the residuals of observed data and calculated data are taken as the objective function.Accordingly,the time-dependent model of bedrock deformation modulus can be established.The method displays its significance in the design of excavation,construction and operation management of dam base and high slope.

关键词： dam base rebound deformation modulus inverse analysis method time-dependent model Xiaowan Hydropower Station

Is a nanorod (or nanotube) with a lower Young’s modulus stiffer? Is not Young’s modulus a stiffness indicator?

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Science China(Physics,Mechanics & Astronomy) 2010年第4期53卷 712-724页

作者： Lim C. W. Department of Building and Construction City University of Hong Kong

It has been a known fact in classical mechanics of materials that Young’s modulus is an indicator of material stiffness and materials with a higher Young’s modulus are stiffer. At the nanoscale, within the scope and under specific circumstances described in this paper, however, a nanorod (or a nanotube) with a smaller Young’s modulus (smaller stress-strain rate) is stiffer. In such a scenario, Young’s modulus is not a stiffness indicator for nanostructures. Furthermore, the nonlocal stress-strain rate is dependent on types of load, boundary conditions and location. This is likely to be one of the many possible reasons why numerous experiments in the past obtained significantly varying values of Young’s modulus for a seemingly identical nanotube, i.e. because the types of loading and/or boundary conditions in the experiments were different, as well as at which point the property was measured. Based on the nonlocal elasticity theory and within the scope of material and geometric linearity, this paper reports the strange and hitherto unrealized effect that a nanorod (or a nanotube) with a lower Young’s modulus (smaller stress-strain rate) indicates smaller extension in tensile analysis. Similarly, it is also predicted that a nanorod (or a nanotube) with a lower Young’s modulus results in smaller bending deflection, higher critical buckling load, higher free vibration frequency and higher wave propagation velocity, which are at all consequences of a stiffer nanostructure.

关键词： nanorod nanotube nonlocal stress nonlocal elasticity stiffness tensile Young’s modulus