The influence of a non‐associated flow rule on the calculation of the factor of safety of soil slopes

This paper presents a method that incorporates a non‐associated flow rule into the limit analysis to investigate the influence of the dilatancy angle on the factor of safety for the slope stability analysis. The proposed method retain's the advantage of the upper bound method, which is simple and has no stress involvement in the calculation of the energy dissipation and the factor of safety. Copyright © 2001 John Wiley & Sons, Ltd.     

Risk Assessment and Disaster Management for Natural and Anthropogenically Induced Geologic Hazards: Application to the Preolkhon Region,Western Lake Baikal,Siberia, Russia

In the Western Lake Baikal, recent Baikal Rift's tectonics control the topography, seismicity, climate, geomorphology, and economy. Scarps, facets, structural terraces, horsts and grabens, and trapezoid valleys can be clearly observed. They have been generated by the recent tectonic movements along the faults and represent a serious geologic hazard. The specific geological conditions predetermine a unique variety of landscapes. Thus, the main type of the economy is tourism. However, unorganized tourism leads to the degradation of the unique landscapes. It increases risk and requires disaster management. Three criteria has been used for risk assessment: (1) degree of geologic hazard; (2) degree of landscape degradation; and (3) degree of the economy's vitality. The high ecological significance and low stability to antropogeneous pressure are typical for landscapes of the Western Lake Baikal. Thus, some special activities of disaster management should be implemented based on our investigation.     

美国板块边界观测(PBO)中的钻孔应变观测设备

介绍美国的板块边界观测(PBO)项目中的钻孔应变观测和钻孔应变观测设备,如钻孔应变仪、钻孔应变仪的辅助观测设备、数据采集、数据传输、电源系统、仪器的防护装置等,并介绍其技术要求.     

南方公益性页岩气调查研究进展

2019—2021年期间,由中国地质调查局油气资源调查中心牵头组织实施的“南方页岩气地质调查工程”,以实现“新区、新层系、新类型、新认识”四新领域油气调查战略发现和突破,推动创建页岩气勘查开发新格局为目标,按照总体部署、分步实施、点上突破、面上评价原则,重点开展了南方复杂构造区页岩气地质调查与评价工作。圈定并优选了一批页岩气远景区和有利区,部署实施了二维地震、参数井和压裂试气工程,实现了长江上游新区新层系页岩气重大突破和发现,完成垭紫罗裂陷槽、皖江、川西南等重点地区页岩气资源潜力评价。这些成果大大提振了南方复杂构造区页岩气油气资源勘查的信心,推动了油气地质调查与科技创新的深度融合,形成了页岩气成藏理论新认识和调查评价新技术,发挥了公益性油气资源调查的引领和带动作用。     

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基于社会属性的北京城市居民居住环境安全性评价

以北京市城八区和外城五个有代表性的地区为调查研究对象,以2005年的大规模调查问卷为基础数据,运用数理统计和GIS分析手段对北京城市居民自身居住环境安全性的评价做出分析.结果显示,北京市居民对自身居住环境安全性总体较为满意,但不同类型人群对居住环境安全性的评价差别明显,其中高知青年和富裕人群的满意度最高,而贫困老年人群满意度最差.从空间差异来看,内城和城北是安全性评价较好的地区,外城和城南地区评价较差,城市东西方向上的评价值无明显空间差别.     

沈阳城市应急避难场所的识别、空间格局与服务功能

以沈阳市为例,运用高分辨率遥感影像识别城市应急避难场所,采用空间插值、波段集统计等方法刻画应急避难场所空间分布及其与人口的空间匹配性,通过栅格成本分析和加权Voronoi图等方法测算空间可达性并划分其服务区范围。研究表明:(1)沈阳市应急避难场所分布呈现出"小集聚、大分散"的基本格局,与人口分布的空间匹配性差;(2)应急避难场所可达性表现出空间异质性,大型用地对整体格局起到主要塑造作用;(3)研究区域可划分为14个较为明确的应急避难场所服务区,不同服务范围在空间上存在大小、数量和构成上的差异。最后,从城市安全视角对沈阳市应急避难场所的空间布局提出优化建议,为政府部门决策提供科学依据与政策参考。     

经济层面和技术层面的碳减排研究

相关资料和事实表明,全球气候发生了很大的变化。二氧化碳是温室效应中最重要的温室气体,碳减排工作是缓解温室效应的一项重要措施,为当前科学研究热点之一。本文主要从经济和技术两个方面,较为系统和全面地介绍了当前碳减排方面的研究进展。经济层面的研究,包括数量化模型、碳税机制和碳减排附加效应几个方面。专业技术方面的研究,包括对碳行为的源汇和贮量的计算研究、碳循环研究、以及减少碳排放的工业技术的运用等。文章还简要提出了中国在碳减排研究方面应采取的几点措施。     

南堡油田保持中深层泥页岩井壁稳定钻井液研究

在南堡油田中深层钻井过程中,东二、东三、沙一段泥页岩的剥落掉块经常造成井壁坍塌掉块、钻具阻卡、电测遇阻等井下复杂情况。分析了中深层泥页岩的理化特性,研究探讨了泥页岩的坍塌机理。在此基础上,提出了选用强封堵抑制型钻井液是有效抑制中深层泥页岩剥落掉块的根本措施。这一研究成果对于在南堡油田中深层开发工程中提高钻速、减少井下复杂情况发生具有重要意义。     

Pesticide-related Food Safety Risks: Farmers’ Self-protective Behavior and Food Safety Social Co-governance

This article investigates the sources of vegetables consumed by farmers, their perception of pesticide-related food safety risks and the behaviors they engage in to protect themselves, and explores the implications for the social co-governance (shehui gongzhi) of food safety emphasized by China’s recent Food Safety Law. The research site is a county in Yunnan Province where vegetable growing is the major source of income and livelihood for local farmers. We surveyed 417 farmers and collected 776 vegetable samples from 377 surveyed farmer households and tested them for organophosphate and carbamate pesticide residues using PR-12N Rapid Detection Instrument for Pesticide Residues. The results showed that farmers know about the risks to food safety caused by pesticides used in vegetable growing and they purposely avoid these risks by mainly consuming vegetables planted in home gardens or private plots that use little or no pesticides. Vegetable samples from these private plots had the lowest positive rate of pesticide residues (6.10%), compared with vegetable samples from commercial farmland (13.73%) and markets (12.66%), and the difference was statistically significant (X²=9.69,0.005相似文献