Effect of non-linear soil deformation on the interaction among energy piles

This study investigates the effect of non-linear soil deformation on the displacement interaction among energy piles. The work is based on interaction factor analyses of full-scale pile group tests, whose results are compared with experimental evidence. The results presented highlight the tendency of interaction factor analyses that ignore non-linear soil deformation to overestimate the interaction and the displacement of energy pile groups. This outcome, in accordance with previous studies for conventional pile groups subjected to mechanical loads, may be considered in the analysis and design of energy pile groups subjected to thermal (and mechanical) loads through the interaction factor method.     

Influence of single flaw on the failure process and energy mechanics of rock-like material

This paper investigates the influence of a flaw on crack initiation, the failure mode, deformation field and energy mechanism of the rock-like material under uniaxial compression. The results of laboratory test and numerical simulation demonstrate the flaw inclination effect can be classified into three groups: 0–30°, 30–60° and 75–90°. The characteristic stresses increase as the flaw angle increases. The tensile cracks initiate from gentle flaws (α ⩽ 30°) and shear cracks appear at tips of steep flaws (α ⩾ 45°). The input energy, strain energy and dissipation energy of a specimen show approximate increasing trends as the flaw angle increases.     

季节性放牧对黄河源区高寒草甸植被耗水量及水分利用效率的影响

研究季节性放牧对植被耗水量、水分利用效率的影响,是探索如何提高高寒草甸水源涵养能力的重要内容之一。以青藏高原三江源高寒草甸季节性放牧样地与自然放牧样地为研究对象,分析了季节性放牧和自然放牧条件下高寒草甸植被耗水量、水分盈亏量、水分利用效率（WUE）的动态变化及其与环境因素的关系。结果表明：在植被生长季（5-9月）,季节性放牧样地和自然放牧样地植被耗水量在5月开始增加, 7月达最高,分别为160.94 mm和145.96 mm,季节性放牧样地植被总耗水量（395.52 mm）比自然放牧样地（348.14 mm）高13.61%。生长季平均来看,季节性放牧样地和自然放牧样地5-9月水分正盈余,分别为13.58 mm和70.96 mm,但在植物生长旺季（8月）略有亏缺。季节性放牧样地和自然放牧样地植被耗水量均与降水量呈弱的正相关关系。季节性放牧样地植被地上净初级生产量（ANPP）、地下净初级生产量（BNPP）和总的净初级生产量（NPP）比自然放牧样地分别高32.54 g·m^-2、5.96 g·m^-2、38.50 g·m^-2,季节性放牧样地ANPP的水分利用效率（WUE）比自然放牧样地高53.85%,而BNPP、NPP的WUE比自然放牧样地分别低13.06%和9.97%。这表明,季节性放牧可提高植被生产量和耗水量,但对高寒草甸WUE的影响因放牧方式不同导致地上、地下生物量分配格局不同而有所差异。     

塔里木河干流径流损耗及其人类活动影响强度变化

依据塔里木河干流1957-2008 年的年径流量监测数据,计算出干流年径流损耗量,利用线性回归法,对干流年径流损耗量时间序列变化趋势进行分析,建立影响径流损耗的社会经济指标体系,运用层次分析法和权重加权法剖析人类活动影响强度变化趋势,并探讨人为径流损耗的主要原因。研究结果表明：① 近50 多年来,塔河干流年径流损耗量表现出递减变化趋势,但上、中、下游存在差异,上游增加显著,增速约为2.09×10⁸ m³/10a,而中、下游递减趋势显著,减速分别为1.61×10⁸ m³/10a 和2.30×10⁸ m³/10a;② 干流来水量与径流损耗量之间呈明显的正相关,R² = 0.9996,可认为来水量减少是诱发径流损耗量减少的直接原因;③ 人类活动强度指数与人为径流损耗量之间亦呈显著的正相关,R² = 0.9822,说明自20 世纪70 年代中期开始,随着人类活动强度的逐渐增大,人类活动对径流损耗的干扰就处于一个扩大和加重的过程;④ 人口增长、产业结构调整、居民对物质经济的追求等社会经济活动是引起人为径流损耗量增加的主要原因。     

大城市健身消费与地方建构

随着全球消费社会的到来,消费如何重塑人地关系日渐成为人文地理学研究的选题, 西方学界自20 世纪90 年代即开启了消费实践与地理学的全面联结。这种学术观照自然而然地延展到消费关系中折射出来的地理想象、地方认同和空间生产等主题之中。作为城市化衍生的生活方式,健身消费成为身体地理、空间想象和地方建构等研究交汇的重要议题。研究援引建构取向的地方理论以及行动者网络理论,分析行动者对“健身”的转译过程,指出行动者的消费关系社会性地建构了一个地理想象的“健康天堂”,健身的消费想象,与话语权力的凝视和影响是高度相关的。地理空间生产一种功能性消费关系和节点型人地关系,后者将本土消费关系想象式地嵌入到全球消费文化脉络之中,将人地关系从本土联结和延伸到全球。 通过身体实践的方式,行动者网络下的健身消费关系将微区位建构为多层次的地方。地方是一个现实与虚拟、本土与全球交互的关键节点,一种多向度的节点型人地关系可以在地理微区位中得到体现。     

沙漠腹地乔木状沙拐枣对灌水量的生理生态响应

对不同灌水量条件下塔克拉玛干沙漠腹地乔木状沙拐枣（Calligonum arborescens Litv）的水分生理、生长和土壤水分进行了动态测定与分析。结果表明:①在35、24.5 kg·株-1·次-1和14 kg·株-1·次-1的灌水量下,土壤水分活跃层分别为:0～200、0～160 cm和0～100 cm。根系区土壤水分为3%～4%条件下,沙拐枣能正常生长,低于2.5%就会受到水分胁迫。②早晨和午后,沙拐枣的水势随着灌溉后时间的增加而降低,前期降幅较大。随着灌水量的减小,其水势降低较快,在14 kg·株-1·次-1处理下,灌溉3 d后早晨水势和午后水势分别达到-1.3 MPa和-2.19 MPa。③随着灌水量的减少沙拐枣的日耗水量急剧减小,液流速率也快速降低,灌溉后第15天,在24.5 kg·株-1·次-1和14 kg·株-1·次-1的灌水量下沙拐枣液流速率都为双峰型曲线,第25天3个处理都呈双峰型曲线。④不同灌水量下,沙拐枣的基径、新枝长度以及新枝直径的年增长量都随着灌水量的减少而减小,方差分析表明灌水量对新枝长度的影响非常显著(P=0.05)。     

Energy losses in compound open channels

This paper investigates energy losses in compound channel under non-uniform flow conditions. Using the first law of thermodynamics, the concepts of energy loss and head loss are first distinguished. They are found to be different within one sub-section (main channel or floodplain). Experimental measurements of the head within the main channel and the floodplain are then analyzed for geometries with constant or variable channel width. Results show that head loss differs from one sub-section to another: the classical 1D hypothesis of unique head loss gradient appears to be erroneous. Using a model that couple 1D momentum equations, called “Independent Sub-sections Method (ISM)”, head losses are resolved. The relative weights of head losses related to bed friction, turbulent exchanges and mass transfers between sub-sections are estimated. It is shown that water level and the discharge distribution across the channel are influenced by turbulent exchanges for (a) developing flows in straight channels, but only when the flow tends to uniformity; (b) flows in skewed floodplains and symmetrical converging floodplains for small relative flow depth; (c) flows in symmetrical diverging floodplains for small and medium relative depth. Flow parameters are influenced by the momentum flux due to mass exchanges in all non-prismatic geometries for small and medium relative depth, while this flux is negligible for developing flows in straight geometry. The role of an explicit modeling of mass conservation between sub-sections is eventually investigated.     

Social construction functions of consumption space under stratification: The case of Guangzhou

As Chinese cities rapidly transformed themselves into consumerist societies, the relationship between consumers and consumption space under stratification has become a new research area in the field of urban social geography. Based on a consumer behavior analysis, this study explores the relationship between consumption space and the social strata of consumers in typical shopping malls in Guangzhou where the first shopping mall in China was built. The result shows that shopping malls have performed significant constructive functions of organizing consumers from different social classes into different consumption space. For middle- and upper-class consumers, the function of shopping malls centers on utilitarian consumption, identity recognition, and identity construction; whereas for lower-class consumers, its function revolves around pleasure and enjoyment. The symbolism of consumption space is the underlying reason for shopping malls to have their social constructive function. The findings of this research suggest that: 1) a shopping mall is a productive consumption space and a geographical space with subjectivity; 2) the micro-location of a shopping mall has social construction function; and 3) symbolic consumption is the core of social construction.     

Use of the Acoustic Energy Meter (AEM) for rapid geomorphological field assessment of rock hardness: comparison with Schmidt hammer R‐value

Rapid, field‐based assessments of rock hardness are required in a broad range of geomorphological investigations where rock intact strength is important. Several different methods are now available for taking such measurements, in particular the Schmidt hammer, which has seen increasing use in geomorphology in recent decades. This is despite caution from within the engineering literature regarding choice of Schmidt hammer type, normalization of rebound (R‐) values, surface micro‐roughness, weathering degree and moisture content, and data reduction/analysis procedures. We present a pilot study of the use of an Acoustic Energy Meter (AEM), originally produced, tested and developed within the field of underground mining engineering as a rapid measure of rock surface hardness, and compare it with results from a mechanical N‐Type Schmidt hammer. We assess its capabilities across six lithological study sites in southeast Queensland, Australia, in the Greater Brisbane area. Each rock exposure has been recently exposed in the 20th/21st century. Using a ‘paired’ sampling approach, the AEM G‐value shows an inverse relationship with Schmidt hammer R‐value. While both devices show variability with lithology, the AEM G‐values show less scatter than the Schmidt hammer. We conclude that each device can contribute to useful rock hardness testing in geomorphological research, but the AEM requires further field testing in a range of environments, and in particular on older and naturally‐exposed rock surfaces. Future evaluations can extend this pilot study by focusing on sampling procedures, energy sources, and data reduction protocols, within the framework of a comparison study with other rock hardness testing apparatus. Copyright © 2016 John Wiley & Sons, Ltd.     

中小城市家庭生活用能碳排放空间分异——以开封市为例

利用2015年开封市居民家庭生活用能的大样本问卷调查数据,采用探索性空间数据分析（ESDA）和标准差椭圆（SDE）方法,探索城市居住区家庭生活用能碳排放空间分布特征。结果表明：① 家庭生活用能碳排放存在以热点区为主的空间正相关特性,碳排放高值集聚发生在城市新建开发区和建成区向外扩张较快区域,以2000年以后新建高档商品房小区和机关事业单位家属院为主,低值集聚区则发生在建成时间长、后续开发力度小的区域,以老商品房小区和胡同社区为主;② 开封市家庭电力消耗碳排放占生活用能总碳排放的67%,但人均生活用能碳排放空间格局由供暖碳排放决定,且人均供暖碳排放空间格局又由集中供暖碳排放空间格局决定,故降低集中供暖能耗、缩小居民供暖用能差异成为居民生活用能碳减排工作的重中之重;③ 家庭经济状况、集中供暖设施分布和城市发展的空间格局是家庭生活用能碳排放空间依赖性和空间异质性形成的主要驱动因素。