Different sedimentary zones in coral reefs lead to significant anisotropy in the pore structure of coral reef limestone(CRL),making it difficult to study mechanical behaviors.With X-ray computed tomography(CT),112 CRL...Different sedimentary zones in coral reefs lead to significant anisotropy in the pore structure of coral reef limestone(CRL),making it difficult to study mechanical behaviors.With X-ray computed tomography(CT),112 CRL samples were utilized for training the support vector machine(SVM)-,random forest(RF)-,and back propagation neural network(BPNN)-based models,respectively.Simultaneously,the machine learning model was embedded into genetic algorithm(GA)for parameter optimization to effectively predict uniaxial compressive strength(UCS)of CRL.Results indicate that the BPNN model with five hidden layers presents the best training effect in the data set of CRL.The SVM-based model shows a tendency to overfitting in the training set and poor generalization ability in the testing set.The RF-based model is suitable for training CRL samples with large data.Analysis of Pearson correlation coefficient matrix and the percentage increment method of performance metrics shows that the dry density,pore structure,and porosity of CRL are strongly correlated to UCS.However,the P-wave velocity is almost uncorrelated to the UCS,which is significantly distinct from the law for homogenous geomaterials.In addition,the pore tensor proposed in this paper can effectively reflect the pore structure of coral framework limestone(CFL)and coral boulder limestone(CBL),realizing the quantitative characterization of the heterogeneity and anisotropy of pore.The pore tensor provides a feasible idea to establish the relationship between pore structure and mechanical behavior of CRL.展开更多
坑中坑的开挖对于基坑的稳定性有诸多方面的影响,内坑的开挖会造成土体回弹,引起基坑土体抗力的损失,降低基坑的整体稳定性。运用FLAC^(3D)对合肥恒大中心C地块坑中坑式基坑进行了开挖与支护模拟,计算采用摩尔-库伦本构模型,通过模拟计...坑中坑的开挖对于基坑的稳定性有诸多方面的影响,内坑的开挖会造成土体回弹,引起基坑土体抗力的损失,降低基坑的整体稳定性。运用FLAC^(3D)对合肥恒大中心C地块坑中坑式基坑进行了开挖与支护模拟,计算采用摩尔-库伦本构模型,通过模拟计算得出了基坑应力、桩基应力、桩锚应力,验证了基坑中外坑和内坑最易失稳破坏区域,并对利用负泊松比(negative Poisson s ratio,NPR)锚索对该类基坑进行加密支护的控制效果进行了评价。通过施加位移监测得到了不同开挖阶段基坑地表位移、坑中坑底部位移、以及坑中坑周围土体位移,确定了基坑极易发生破坏的区域以及滑动面位置,建立了坑中坑物理模型,并验证了数值模拟的正确性,研究结论可为类似工程条件基坑的开挖及加固提供理论支撑和实践基础。展开更多
In this paper, the content of rockery protection was discussed through the analysis of a series of documents such as the convention, declaration, and regulations concerning heritage protection in accordance with the p...In this paper, the content of rockery protection was discussed through the analysis of a series of documents such as the convention, declaration, and regulations concerning heritage protection in accordance with the principles of authenticity and integrity. Through the analysis of the influence factors of the rockery and its environment, it is proposed that the rockery protection should strengthen environmental protection on the basis of the protection of the body of a rockery. From the perspectives of structure, skill, materials and function, the contents of the rockery protection and the human settlement environment where the rockery is located, the external environment and internal environment of the rockery space were analyzed, and the contents of the rockery protection were preliminarily proposed.展开更多
By summarizing research status of traditional garden,the obstacles and difficulties of garden rockery research are analyzed,and the breakthroughs and advantages of 3D digital technique in garden rockery surveying and ...By summarizing research status of traditional garden,the obstacles and difficulties of garden rockery research are analyzed,and the breakthroughs and advantages of 3D digital technique in garden rockery surveying and mapping are introduced.The rockery in North China University of Technology is taken as the research object.Using many kinds of digital 3D techniques,3D scanning and modeling analysis of the rockery are conducted.Modeling result and accuracy of each technique are analyzed,and application prospect of 3D digital technique in rockery research of classical garden is explored.展开更多
Zhang Yifan is the son of gardening Master Zhang Nanyuan, and his story can only be found in Qi Biaojia's Diary. Qi recorded his communications with Zhang Yifan and Zhang's transformation over Yu Garden in det...Zhang Yifan is the son of gardening Master Zhang Nanyuan, and his story can only be found in Qi Biaojia's Diary. Qi recorded his communications with Zhang Yifan and Zhang's transformation over Yu Garden in detail, thus the diary shows high documentation value. Zhang's transformation over Yu Garden was important for others exploring and understanding the contents, style, and construction period of Zhangs' rockery gardening, and also for spreading Zhangs' style in Yuezhong(the present Shaoxing City, and Xiaoshan District of Hangzhou, including 8 counties of the former Shaoxing Prefecture). This paper summarized and verified the characteristics, contents and construction period of Zhangs' rockery gardening by analyzing the study case, and elaborated the spreading and development of Zhangs' gardening style in Yuezhong.展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.41877267 and 41877260)the Priority Research Program of the Chinese Academy of Sciences(Grant No.XDA13010201).
文摘Different sedimentary zones in coral reefs lead to significant anisotropy in the pore structure of coral reef limestone(CRL),making it difficult to study mechanical behaviors.With X-ray computed tomography(CT),112 CRL samples were utilized for training the support vector machine(SVM)-,random forest(RF)-,and back propagation neural network(BPNN)-based models,respectively.Simultaneously,the machine learning model was embedded into genetic algorithm(GA)for parameter optimization to effectively predict uniaxial compressive strength(UCS)of CRL.Results indicate that the BPNN model with five hidden layers presents the best training effect in the data set of CRL.The SVM-based model shows a tendency to overfitting in the training set and poor generalization ability in the testing set.The RF-based model is suitable for training CRL samples with large data.Analysis of Pearson correlation coefficient matrix and the percentage increment method of performance metrics shows that the dry density,pore structure,and porosity of CRL are strongly correlated to UCS.However,the P-wave velocity is almost uncorrelated to the UCS,which is significantly distinct from the law for homogenous geomaterials.In addition,the pore tensor proposed in this paper can effectively reflect the pore structure of coral framework limestone(CFL)and coral boulder limestone(CBL),realizing the quantitative characterization of the heterogeneity and anisotropy of pore.The pore tensor provides a feasible idea to establish the relationship between pore structure and mechanical behavior of CRL.
文摘坑中坑的开挖对于基坑的稳定性有诸多方面的影响,内坑的开挖会造成土体回弹,引起基坑土体抗力的损失,降低基坑的整体稳定性。运用FLAC^(3D)对合肥恒大中心C地块坑中坑式基坑进行了开挖与支护模拟,计算采用摩尔-库伦本构模型,通过模拟计算得出了基坑应力、桩基应力、桩锚应力,验证了基坑中外坑和内坑最易失稳破坏区域,并对利用负泊松比(negative Poisson s ratio,NPR)锚索对该类基坑进行加密支护的控制效果进行了评价。通过施加位移监测得到了不同开挖阶段基坑地表位移、坑中坑底部位移、以及坑中坑周围土体位移,确定了基坑极易发生破坏的区域以及滑动面位置,建立了坑中坑物理模型,并验证了数值模拟的正确性,研究结论可为类似工程条件基坑的开挖及加固提供理论支撑和实践基础。
基金Sponsored by 2018 Talented Young People Nourishment Program of North China University of Technology(18XN012-025)2017 Scientific Research Project of Beijing Municipal Education Commission(KM201710009013)
文摘In this paper, the content of rockery protection was discussed through the analysis of a series of documents such as the convention, declaration, and regulations concerning heritage protection in accordance with the principles of authenticity and integrity. Through the analysis of the influence factors of the rockery and its environment, it is proposed that the rockery protection should strengthen environmental protection on the basis of the protection of the body of a rockery. From the perspectives of structure, skill, materials and function, the contents of the rockery protection and the human settlement environment where the rockery is located, the external environment and internal environment of the rockery space were analyzed, and the contents of the rockery protection were preliminarily proposed.
基金Sponsored by Scientific Research Plan Project of Beijing Municipal Education Committee in 2017(KM201710009013)Yuyou Youth Project of North China University of Technology in 2018(18XN012-025)
文摘By summarizing research status of traditional garden,the obstacles and difficulties of garden rockery research are analyzed,and the breakthroughs and advantages of 3D digital technique in garden rockery surveying and mapping are introduced.The rockery in North China University of Technology is taken as the research object.Using many kinds of digital 3D techniques,3D scanning and modeling analysis of the rockery are conducted.Modeling result and accuracy of each technique are analyzed,and application prospect of 3D digital technique in rockery research of classical garden is explored.
基金Sponsored by 2017 Scientific Research Fund of Beijing Department of EducationYuyou Youth Project of North China University of Technology in 2018(18XN012-025)
文摘Zhang Yifan is the son of gardening Master Zhang Nanyuan, and his story can only be found in Qi Biaojia's Diary. Qi recorded his communications with Zhang Yifan and Zhang's transformation over Yu Garden in detail, thus the diary shows high documentation value. Zhang's transformation over Yu Garden was important for others exploring and understanding the contents, style, and construction period of Zhangs' rockery gardening, and also for spreading Zhangs' style in Yuezhong(the present Shaoxing City, and Xiaoshan District of Hangzhou, including 8 counties of the former Shaoxing Prefecture). This paper summarized and verified the characteristics, contents and construction period of Zhangs' rockery gardening by analyzing the study case, and elaborated the spreading and development of Zhangs' gardening style in Yuezhong.
