在确定建筑物基础抗浮设防水位时应注意的一些问题   总被引：4，自引：7，他引：4  

张思远 《岩土工程技术》2004,18(5):227-229

建筑物基础抗浮水压力主要受基底所在地层的地下水位控制。在有多层地下水的场地 ,预测最高地下水位时 ,宜分层预测  相似文献   

干旱区绿洲耕地撂荒与复耕对土壤水力性质的影响     

刘斐耀  尤全刚  吴思渊  黄翠华  潘晶  马绍休  陈小杰  薛娴 《中国沙漠》2021,41(6):169-178

土地利用变化会改变土壤质地与结构,影响土壤水力性质,进而改变土壤水分有效性,影响植物生长。由于区域气候的干湿交替与水资源利用效率的提高,干旱区绿洲耕地普遍存在着撂荒-复耕现象。为了明确干旱区耕地撂荒与复耕对土壤水力性质的影响,以民勤绿洲北部边缘的耕地、撂荒地与撂荒复耕地为研究对象,测定0—40 cm深度土壤理化性质,分析不同土地利用下土壤水力性质差异及其影响因素。结果表明：耕地撂荒导致0—40 cm深度黏粒与粉粒比重增加,有机质含量降低,容重降低（P<0.05）,土壤孔隙度显著增加（P<0.05）,犁底层消失;在高水势阶段,土壤持水与导水能力增强,在土壤有效含水量对应的水势阶段,土壤持水与导水能力变差,有效含水量显著降低（P<0.05）。撂荒地复耕后,0—40 cm深度黏粒与粉粒含量继续增加,有机质含量转而增加,容重增加（P<0.05）,土壤孔隙度降低（P<0.05）,犁底层重新出现,土壤持水与导水能力又逐渐趋向于耕地水平。撂荒对干旱区绿洲土壤肥力与蓄水能力的提升不显著,而留茬免耕、深耕灭茬还田等保护性耕作措施能有效提高持水能力。利用研究区易测的土壤黏粒、砂粒含量与土壤容重,采用多元线性回归方法,可以准确、快捷预测土壤水分常数,这将有利于研究区农田灌溉制度的准确制定与优化,以及耕地利用变化对土壤水力性质影响的快速评估。  相似文献   

Flood assessment and early warning of the reoccurrence of river blockage at the Baige landslide     

GAO Yunjian  ZHAO Siyuan  DENG Jianhui  YU Zhiqiu  RAHMAN Mahfuzur 《地理学报(英文版)》2021,31(11):1694-1712

On 10th Oct.and 3rd Nov.2018,two successive landslides occurred in the Jinsha River catchment at Baige Village,Tibet Autonomous Region,China.The landslides blocked the major river and formed the barrier lake,which finally caused the huge flood disaster loss.The hillslope at Baige landslide site has been still deforming after the 2018 slidings,which is likely to fail and block the Jinsha River again in the future.Therefore the investigation of 2018 flood disaster at the Baige landslide is of a great significance to provide a classic case for flood assessment and early warning for the future disaster.The detailed survey revealed that the outstanding inundations induced bank collapse disasters upstream the Baige landslide dams,and the field investigations and hydrological simulation suggested that the downstream of the Baige landslide were seriously flooded due to the two periods of the outburst floods.On these bases,the early warning process of potential outburst floods at the Baige landslide was advised,which contains four stages:Outburst Flood Simulating Stage,Outburst Flood Fore-casting Stage,Emergency Plan and Emergency Evacuation Stage.The study offers a con-ceptual model for the mitigation of landslides and flood disasters in the high-relief mountain-ous region in Tibet.  相似文献   

The Role of Local Knowledge in the Risk Management of Extreme Climates in Local Communities: A Case Study in a Nomadic NIAHS Site     

WANG Guoping  YANG Lun  LIU Moucheng  LI Zhidong  HE Siyuan  MIN Qingwen 《资源与生态学报(英文版)》2021,12(4):532-542

In the context of climate change, research on extreme climates and disaster risk management has become a crucial component of climate change adaptation. Local communities, which have been facing extreme climates for a long time in their production and daily life, have developed some locally applicable traditional knowledge that has played an important role in their adaptation to extreme climate and disaster risk management. Therefore, this research aims to link Local knowledge (LK) to community extreme climate disaster risk management in order to construct a conceptual model. It then takes the extreme climate adaptation strategy of traditional nomads in a temperate grassland of China as an example to analyze the role of LK in extreme climate adaptation using the proposed theoretical framework. The main research objectives of this study are: (1) To construct a conceptual model to illustrate the relations among extreme climate events, risk management, LK, and farmers' adaptation strategies; (2) To apply the theoretical framework to a field case to reveal context-specific extreme climate adaptation mechanisms with LK as a critical component; (3) To test the framework and provide suggestions for the extreme climates adaptation, and the conservation of LK related to climate change adaptation. The results show that from the perspective of disaster risk management, local communities could manage extreme climates as a disaster risk through adaptation strategies formed from LK, because as a knowledge system, LK contains relevant knowledge covering the whole process of disaster risk management.  相似文献   

The Role of the Important Agricultural Heritage Systems in the Construction of China’s National Park System and the Optimisation of the Protected Area System     

HE Siyuan  DING Lubin  MIN Qingwen 《资源与生态学报(英文版)》2021,12(4):444-452

Conservation-compatible development of rural communities is an important part of nature conservation objectives. Understanding the role of agriculture, which is often practiced in or bordering the protected areas in rural China, is critical for managing conservation networks considering that limited spatial areas are available for enclosed protected areas. Important Agricultural Heritage Systems stand out for their multi-functionality, and some of their values are compatible with nature conservation. This paper examined the concept, management objectives and resource management characteristics of the Important Agricultural Heritage Systems (IAHS) by analysing their interactions with national parks in terms of community development. The results reveal that management strategies of dynamic conservation, integrated protection and adaptive management of the IAHS can contribute to those national park management objectives concerning conservation-compatible livelihood. However, the typology of the protected area system, including the traditional agricultural system as a new type, needs further consideration.  相似文献   

基于安全事件的三维场景自动建模方法     

廖思远  刘雪峰  王伟  陈泽强 《测绘与空间地理信息》2021,44(5):12-16

安全事件具有发生地点随机、范围广、突发性、实时性等特点,传统的手工建模无法满足安全事件在较大区域内任意地点快速搭建三维场景的需要.为了解决上述问题,本文提出了一种基于矢量数据的三维场景快速自动建模方法.主要实现以下功能:1)矢量数据经过矢量数据解析、墨卡托投影、多边形三角化、白模生成、纹理生成等过程,快速生成大规模三维建筑物模型;2)基于Gaea Explorer平台设计并实现了大规模模型数据的瓦片快速调度方法,在三维地球中自动加载当前视角内建筑物模型集合,实现了较大区域内任意地点三维场景的自动快速搭建和场景的流畅切换.实验结果表明,本文提出的基于矢量数据的三维场景自动建模方法可以满足社会安全事件模拟的需要.  相似文献   

Discussion of Grading Evaluation Criteria to Study Shale Oil Resources in Zhanhua Sag     

CHEN Weitao  JIANG Zhenxue  SU Siyuan  CHEN Lei  and JI Wenming 《《地质学报》英文版》2015,89(Z1):12-12

<正>The huge resources potential of shale oil has been paid more and more attention.The method to correctly evaluate the shale oil potential is the key for resources evaluation.Some foreign scholars argued that the amount of hydrocarbon-bearing per unit organic carbon(S_1/TOC)was effective to determine the producible shale oil,known as"Oil crossover",while the method has some limitation  相似文献   

西北干旱农牧交错带地表基质调查成果经验     

张思源  袁帅  邢怡  刘永新  王永亮 《地质论评》2024,70(S1):331-332

  相似文献   

川藏铁路西藏昌都段生态保护重要性评价     

王思源  赵敏敏  闫晶  马鑫  刁玉杰  付雷  罗倩 《现代地质》2021,35(1):234-243

生态系统服务功能与生态系统敏感性是衡量生态系统质量及实现高质量生态文明建设的重要依据。川藏铁路沿途跨越多个自然地理单元,生态环境保护是铁路规划、建设及运行过程中面临的关键问题。以川藏铁路西藏昌都段为研究对象,采取资料分析与野外调查结合的手段,运用生态评价模型对研究区的生态系统服务和生态脆弱性进行分析,并基于研究结果对铁路途经区域的生态保护重要性进行评价。结果表明,当前昌都境内川藏铁路涉及的生态保护极重要区、重要区和一般重要区占比分别为42.19%、52.69% 和5.12%。评价结果有助于在铁路规划、建设及运营过程中对工程活动进行合理布局,有针对性地降低对生态系统的负面影响,达到社会经济效益和生态效益双赢的目的。  相似文献   

Response of a loess landslide to rainfall: observations from a field artificial rainfall experiment in Bailong River Basin,China     

Guan Chen  Xingmin Meng  Liang Qiao  Yi Zhang  Siyuan Wang 《Landslides》2018,15(5):895-911

Rainfall-induced landslides are a significant hazard in many areas of loess-covered terrain in Northwest China. To investigate the response of a loess landslide to rainfall, a series of artificial rainfall experiments were conducted on a natural loess slope, located in the Bailong River Basin, in southern Gansu Province. The slope was instrumented to measure surface runoff, pore water pressure, soil water content, earth pressure, displacement, and rainfall. The hydrological response was also characterized by time-lapse electrical resistivity tomography. The results show that most of the rainfall infiltrated into the loess landslide, and that the pore water pressure and water content responded rapidly to simulated rainfall events. This indicates that rainfall infiltration on the loess landslide was significantly affected by preferential flow through fissures and macropores. Different patterns of pore water pressure and water content variations were determined by the antecedent soil moisture conditions, and by the balance between water recharge and drainage in the corresponding sections. We observed three stages of changing pore water pressure and displacement within the loess landslide during the artificial rainfall events: Increases in pore water pressure initiated movement on the slope, acceleration in movement resulting in a rapid decrease in pore water pressure, and attainment of a steady state. We infer that a negative pore water pressure feedback process may have occurred in response to shear-induced dilation of material as the slope movement accelerated. The process of shear dilatant strengthening may explain the phenomenon of semi-continuous movement of the loess landslide. Shear dilatant strengthening, caused by intermittent or continuous rainfall over long periods, can occur without triggering rapid slope failure.  相似文献