Model tests on interaction between soil and geosynthetics subjected to localized subsidence in landfills

In a landfill, excessive tensile strains or failure of the liner system due to localized subsidence underneath the geosynthetic liner, is a concern in design and operation of the landfill. The localized subsidence can be commonly withstood by reinforcements such as geogrids. A total of nine model tests were carried out to study the influence of soil arching in overburden sandy soil on the geosynthetics and the interaction between the soil and the geosynthetics. The localized subsidence was modeled by a strip trapdoor under the geosynthetic reinforcements. The reinforcement includes several layers of polyvinylchlorid (PVC) membrane or both PVC membrane and a compacted clay layer. Test results show that the vertical soil pressure acting on the geosynthetics within the subsidence zone is strongly related to the deflection of the geosynthetics. The soil pressure acting on the deflected geosynthetics will decrease to a minimum value with respect to its deflection if the final deflection is large enough, and this minimum value is almost independent of the overburden height. Otherwise, the deflection of geosynthetics cannot result in a full degree of soil arching, and the soil pressure within the subsidence zone increases with the increase of overburden height. Deflections and strains of the geosynthetics obviously decrease with the increase of their tensile stiffness. The presence of a compacted clay layer buffer can therefore reduce both deflections and strains of the geosynthetics. Finally, a composite liner structure is recommended for landfills to withstand the localized subsidences.     

基于“理论力学”慕课的混合教学模式的实施

慕课和泛雅平台下的云课程是现代技术教育下的一种新型教学模式。“理论力学”是理工科学生一门重要的技术基础课程,如何提高理论力学的教学质量,一直是困扰高等学校教师的一个难题。重点介绍了在理论力学慕课的基础上使用泛雅网络教学平台,通过该平台学生可以自主观看视频,进行网上自我检测和网上作业。线上学习弥补了理论力学课时严重不足的情况,而课堂教学可以更好地了解学生线上学习情况,相得益彰。通过这两种教学模式的融合,很大程度上提高了理论力学的教学质量,调动了学习力学的积极性和主动性。     

趣味力学通识选修课初探

为了让更多的学生了解生活和工程中的一些力学现象,感受力学的精妙,科普力学知识,开设了趣味力学通识选修课。以理论联系实际的方法,通过选用大量有趣的力学现象,介绍了涉及理论力学、材料力学、流体力学和振动力学相关的知识点,从而开阔了学生视野,增强了学生对力学课程的兴趣和对自然科学的探索精神。     

Automated soil resources mapping based on decision tree and Bayesian predictive modeling

This article presents two approaches for automated building of knowledge bases of soil resources mapping.These methods used decision tree and Bayesian predictive modeling,respectively to generate knowledge from training data.With these methods,building a knowledge base for automated soil mapping is easier than using the conventional knowledge acquisition approach.The knowledge bases built by these two methods were used by the knowledge classifier for soil type classification of the Longyou area,Zhejiang Province,China using TM bi-temporal imageries and GIS data.To evaluate the performance of the resultant knowledge bases,the classification results were compared to existing soil map based on field survey.The accuracy assessment and analysis of the resultant soil maps suggested that the knowledge bases built by these two methods were of good quality for mapping distribution model of soil classes over the study area.     

Predicting writing skill development with word recognition and preschool readiness skills

In this longitudinal study, the writing skill development of154 Finnish-speaking children was followed from preschool to thethird grade. The focus was on predictive associations betweenpreschool writing readiness skills and later mechanics ofwriting, as well as between word recognition skill, mechanics ofwriting, and composition coherence. In addition, comparisons weremade between boys and girls to see to what extent writing skilldevelopment is gender-specific. Multi-group structural equationmodeling was used for statistical analysis. The results indicatedthat both mechanics of writing and composition coherence could bepredicted from performance on the same skill at an earlier pointin time. Preschool measures of phonological and visual-motorskills predicted later mechanics of writing. Word recognitionworked as a predictor of later mechanics of writing andcomposition coherence, but only starting from second grade, whenthe development of the word recognition skill had becomestabilized at a high enough level. Furthermore, first grademechanics of writing predicted second grade compositioncoherence, but only at this early stage of productive writingwhen there were still difficulties in the mechanics of writing.Girls were better at tasks measuring mechanics of writing andwrote more coherent stories than boys. The gender difference inthe mechanics of writing at the first grade level was explainedby the presented model. Educational implications were discussed.     

二维柔性铰链机械设计及特性分析

本文主要对二维柔性铰链驱动平台的运动特性、力学性能进行分析并导出双柔性平行四杆柔性铰链结构的设计与加工方法。     

关于动量概念的建立与动量的表述

动量是物理学中重要的基本概念，动量概念的建立在物理学理论的发展上具有重要的作用和地位。本文阐述了动量概念的建立过程,给出了有关动量的表述。     

“材料力学”课程思政的教学探索

“材料力学”课程思政的教学就是要在教书和育人的各个环节融入思想政治教育元素,不断加强和提高学生的思想政治理念。根据教育部召开的新时代全国高等学校本科教育工作会议提出的立德树人的成效是检验学校一切工作的根本标准,在教学环节增加“思政元素”,不仅提高了学生们的学习兴趣和理解能力,而且对学生的思想政治素养有积极地促进作用。     

水土流失对白莲河库区生态环境的影响及对策

白莲河库区水土流失是导致库区生态环境恶化的主要原因之一,本文主要从库区水土流失的成因、危害和治理措施等几个方面进行了探讨,并提出了治理库区水土流失的措施和建议,对治理库区日益恶化的生态环境具有一定的指导意义。     

与虚拟仿真实验相融合的结构力学课程教学创新与实践

分析目前结构力学课程教学过程中存在的过多关注基础性忽视专业应用性的问题,通过将虚拟仿真实验融合进传统的结构力学理论教学,进行课程教学的创新和实践,探索更灵活有效的教学模式,从而使结构力学成为让学生从土木工程中的力学基本理论过渡到工程实际应用的重要桥梁。