坚硬顶板综采工作面推进速度对矿压规律影响研究

以顾桥煤矿坚硬顶板综采工作面工程地质条件为背景,运用理论分析、数值模拟和现场实测手段,分析了开采速度对工作面覆岩运动、围岩破坏、应力分布和液压支架承载特性的影响。研究结果表明:1个周期来压内工作面落煤引起的岩梁刚性回转下沉量是一定的,工作面作业循环时间引起的岩梁蠕变下沉量与岩梁刚性回转下沉量呈正比,加快工作面推进速度仅减少围岩体蠕变引起的岩梁下沉部分。工作面开采速度增加,覆岩塑性区发育范围减小,煤壁应力集中位置变浅、应力集中系数变小。工作面快速推进时,液压支架承载多为2次増阻和3次増阻,支架工作阻力较小;缓慢推进时,液压支架承载多为1次急增阻,载荷近似呈线性增长,支架工作阻力较大。     

尾矿坝溃决泥浆运动机制及其预测模型研究

以尾矿溃坝砂流下游演进动力学过程为研究重点,综合运用水文学及水动力学等运动理论和数值计算方法,建立描述尾矿坝溃决泥浆运动的数学模型,采用VOF模型对溃坝后的砂流运动过程进行数值模拟。以某溃决尾矿坝为例,对溃坝后下泄砂流演进过程进行模拟,模拟得到的最终影响范围及泥深均与该溃决尾矿坝溃后的现场观测结果相吻合,证明了模拟的有效性和正确性。     

煤壁应力峰值动态移动诱发封孔漏气机理研究

基于有效应力原理分析了煤体吸附瓦斯对煤体强度的影响,提出应用煤体单轴抗压强度衰减比k_σ表征瓦斯压力变化对煤体强度的影响;应用数值分析方法研究了煤体瓦斯抽采前后煤壁前方煤体应力、屈服破坏范围的变化。结果表明,抽采期间,煤壁前方煤体应力峰值处于"动态移动"状态,致使煤壁前方的屈服破坏区间同时发生移动,水泥封孔段由受压转为应力卸载状态而发生膨胀破坏,在封孔段水泥与煤壁之间形成松动漏气通道,孔外空气将沿该漏气通道进入孔内,使抽采浓度降低。为提高带压封孔方法的封孔效果,应科学判定抽采前期煤体应力峰值区间,并考虑抽采期间煤体"应力峰值移动"的影响,在应力峰值区间适当向两侧延伸封孔段长度,注重封孔器材和封孔材料的研制和选择。     

Seeding agroecology through new farmer training in Canada: knowledge,practice, and relational identities

As a concept, agroecology emphasises the interweaving of scientific and traditional ecological knowledge and is evolving in conjunction with farmer-led social movements from around the world addressing the health, equity and ecological sustainability of food systems. In Canada, many new agroecological farmers come from non-farming backgrounds and are finding limited training opportunities and support structures. While there is a growing literature on the evolution of agroecology, there is limited research on the existence and impact of training programmes on the subject-formation of new farmers. In this paper, we consider the subject-formation of new agroecological farmers through a case study of the Everdale Community Learning Centre, one of Canada’s only agroecological farm schools. In particular, we explore how the knowledge, practice, and relational identities of participating graduates are informed by and build on the science, practice, and movement of agroecology. Drawing on a survey and interviews with past participants, we found that Everdale’s education programme contributes to an agroecological subject-formation by promoting the co-creation of place-based agricultural knowledge; teaching the complexities of agroecology practice through both experiential and theoretical training; and, building a supportive community of peers. We conclude with reflections on ways to encourage a greater diversity of new farmer entrants and opportunities to support training programme graduates in establishing successful farms. These findings provide insight into developing new agroecological farmers and supporting the growing agroecological movement in Canada.     

邦多-措麦地区新构造运动特征及其演化简析

文章将邦多—措麦地区新构造运动划分为冈底斯北缘稳定上升区、冈底斯掀斜上升区和纵贯南北的当惹雍错—许如错地堑区。概述了研究区新构造运动以垂直运动、水平运动和火山、地震活动等为主要表现形式。从现代地貌格局、活动构造形迹、近代岩浆作用和地热、地震等方面，阐述了研究区新构造运动的基本特征。根据中新世以来的构造作用、沉积特征、岩浆活动等特征，对区内的新构造运动的演化作了初步总结，大致划分为4个强烈活动期，即中新世晚期、上新世末—早更新世初、早更新世末和中更新世末—晚更新世。     

从新构造运动观点论钱塘江阶地古红土资源

阶地古红土在华南分布很广,是一项重要资源。本文以钱塘江中下游为例,查明:阶地古红土分布决定于局部新构造运动升沉量与构造断块活动;愈到下游,古红土土层愈厚;在每一地段,阶地愈高,红壤化作用愈深,表现在铁的活化度（Fe_o/Fe_d）减低,粘粒的 SiO₂/Al₂O₃变小,酸性与粘性增强等。按新构造运动抬升时间与幅度,古红土还可划分为Q₂与Q₃两类,其上土壤的理化性质、作物的适种性及开发条件都不相同。二者的面积比（Q₂/Q₃）则与各区域新构造运动特点有关。     

Aftermath of natural disasters: Coping through residential mobility

Most studies of population movement have concentrated on the more developed nations and on trends that have not been influenced by man-made or natural disasters. The experience of developing countries in the Caribbean basin, as studied after the Guatemalan earthquake of 1976 and the impact of Hurricane David in the Dominican Republic of 1979, highlights the importance of socio-economic factors in the decision to make permanent migrations after a disaster, regardless of whether the migrant had personally suffered losses. In many cases the opportunities for personal betterment created by the disaster acted as a catalyst and accelerated a previously-existing trend of migration.     

轮南地区奥陶系天然裂缝的发育机理及其对流体活动的控制

地下天然裂缝是导致地质灾害的主要原因之一 ,其机理研究是防灾的基础。轮南地区奥陶系天然裂缝的埋深在 5 0 0 0m以下 ,其发育受多种因素控制 ,且在地质演化过程中经历了多期发育而成 ,发育机理非常典型、复杂。笔者通过观察、描述岩心的裂缝发育特征 ,分析了深度、温度、围压等的变化以及剥蚀、裂缝充填对地下岩体力学性质的影响 ;进而建立综合数学模型 ,对裂缝发育概率分布和发育特点做出预测 ;根据计算结果 ,分析了轮南地区奥陶系天然裂缝的发育机理 ;通过天然裂缝分布与井内流体测试结果的对比分析 ,探讨了裂缝分布对地下流体活动的控制作用。     

喷雾液滴在容器气流中的运动分析与计算

对喷雾干燥脱硫中液滴在具有气流的竖立容器内的运动情况进行了分析，提出了有关计算式，为喷雾干燥脱硫容器和其他类似容器的设计提供了较为科学的计算依据。     

采空区对地表建筑物的影响评价方法研究

为研究金属矿山采动灾害影响,论述了金属矿山采空区上覆岩层移动对地表建筑物影响评价理论和技术方法,即"三带理论"、岩石移动带理论和数值模拟方法;指出了金属矿山空区稳定性和岩石移动的主要影响因素。结合某铁矿采空区的实际情况,综合应用这3种方法对该铁矿进行了定性、定量评价。分析3种评价方法的特点,旨在探索金属矿山的采动影响评价方法,以便保护矿区附近建筑物的安全,减小采动灾害对矿山企业及附近居民生命财产损失。