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71.
72.
复杂条件下的地下管线探测技术 总被引:6,自引:0,他引:6
以深圳市某大道顶管施工地下管线的探测成果为例,研究了在复杂场地条件下,探测地下管线的地球物理方法和技术,着重研究了电磁感应探测法.认为在复杂条件下,对钢质煤气管,应采用电磁感应探测法;对钢质或铁质给水管,应采用直接法;对电力管和电信管,应尽量采用夹钳法;对排水(管)渠等非金属材质管线,应采用地质雷达探测的方法. 相似文献
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Nicolas Baghdadi Gilles Grandjean Didier Lahondère Philippe Paillou Yannick Lasne 《Comptes Rendus Geoscience》2005,337(8):719-728
The potential of radar imagery in geological exploration was investigated at a study site in Mauritania (Akjoujt region). Compared with optical images, the results obtained show how radar imagery can help not only in detecting surface geological structures such as dykes and veins, but also mapping subsurface structures beneath a shallow layer of sand (palaeochannels). The mapping potential was found to be much better at long wavelengths than at short ones (L-band, compared with C- and X-band). As for optical images, their contribution is much more limited in the mapping of surface geological structures, and inappropriate for detecting subsurface structures. We conclude that spatial remote sensing enables the improvement of existing geological maps and the optimization of cartographic surveying. To cite this article: N. Baghdadi et al., C. R. Geoscience 337 (2005). 相似文献
75.
Including spatial distribution in a data‐driven rainfall‐runoff model to improve reservoir inflow forecasting in Taiwan 下载免费PDF全文
Multi‐step ahead inflow forecasting has a critical role to play in reservoir operation and management in Taiwan during typhoons as statutory legislation requires a minimum of 3‐h warning to be issued before any reservoir releases are made. However, the complex spatial and temporal heterogeneity of typhoon rainfall, coupled with a remote and mountainous physiographic context, makes the development of real‐time rainfall‐runoff models that can accurately predict reservoir inflow several hours ahead of time challenging. Consequently, there is an urgent, operational requirement for models that can enhance reservoir inflow prediction at forecast horizons of more than 3 h. In this paper, we develop a novel semi‐distributed, data‐driven, rainfall‐runoff model for the Shihmen catchment, north Taiwan. A suite of Adaptive Network‐based Fuzzy Inference System solutions is created using various combinations of autoregressive, spatially lumped radar and point‐based rain gauge predictors. Different levels of spatially aggregated radar‐derived rainfall data are used to generate 4, 8 and 12 sub‐catchment input drivers. In general, the semi‐distributed radar rainfall models outperform their less complex counterparts in predictions of reservoir inflow at lead times greater than 3 h. Performance is found to be optimal when spatial aggregation is restricted to four sub‐catchments, with up to 30% improvements in the performance over lumped and point‐based models being evident at 5‐h lead times. The potential benefits of applying semi‐distributed, data‐driven models in reservoir inflow modelling specifically, and hydrological modelling more generally, are thus demonstrated. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
76.
The June 2013 Alberta catastrophic flooding event – part 2: fine‐scale precipitation and associated features 下载免费PDF全文
B. Kochtubajda R. E. Stewart S. Boodoo J. M. Thériault Y. Li A. Liu C. Mooney R. Goodson K. Szeto 《水文研究》2016,30(26):4917-4933
Data obtained from a variety of sources including the Canadian Lightning Detection Network, weather radars, weather stations and operational numerical weather model analyses were used to address the evolution of precipitation during the June 2013 southern Alberta flood. The event was linked to a mid‐level closed low pressure system to the west of the region and a surface low pressure region initially to its south. This configuration brought warm, moist unstable air into the region that led to dramatic, organized convection with an abundance of lightning and some hail. Such conditions occurred in the southern parts of the region whereas the northern parts were devoid of lightning. Initially, precipitation rates were high (extreme 15‐min rainfall rates up to 102 mm h?1 were measured) but decreased to lower values as the precipitation shifted to long‐lived stratiform conditions. Both the convective and stratiform precipitation components were affected by the topography. Similar flooding events, such as June 2002, have occurred over this region although the 2002 event was colder and precipitation was not associated with substantial convection over southwest Alberta. Copyright © 2016 Her Majesty the Queen in Right of Canada. Hydrological Processes. © John Wiley & Sons, Ltd. 相似文献
77.
Water level observations from unmanned aerial vehicles for improving estimates of surface water–groundwater interaction 下载免费PDF全文
Filippo Bandini Michael Butts Torsten Vammen Jacobsen Peter Bauer‐Gottwein 《水文研究》2017,31(24):4371-4383
Integrated hydrological models are usually calibrated against observations of river discharge and piezometric head in groundwater aquifers. Calibration of such models against spatially distributed observations of river water level can potentially improve their reliability and predictive skill. However, traditional river gauging stations are normally spaced too far apart to capture spatial patterns in the water surface, whereas spaceborne observations have limited spatial and temporal resolution. Unmanned aerial vehicles can retrieve river water level measurements, providing (a) high spatial resolution; (b) spatially continuous profiles along or across the water body, and (c) flexible timing of sampling. A semisynthetic study was conducted to analyse the value of the new unmanned aerial vehicle‐borne datatype for improving hydrological models, in particular estimates of groundwater–surface water (GW–SW) interaction. Mølleåen River (Denmark) and its catchment were simulated using an integrated hydrological model (MIKE 11–MIKE SHE). Calibration against distributed surface water levels using the Differential Evolution Adaptive Metropolis algorithm demonstrated a significant improvement in estimating spatial patterns and time series of GW–SW interaction. After water level calibration, the sharpness of the estimates of GW–SW time series improves by ~50% and root mean square error decreases by ~75% compared with those of a model calibrated against discharge only. 相似文献
78.
Measurement of stream cross section using ground penetration radar with Hilbert–Huang transform 下载免费PDF全文
This study presents a new method to measure stream cross section without having contact with water. Compared with conventional measurement methods which apply instruments such as sounding weight, ground penetration radar (GPR), used in this study, is a non‐contact measurement method. This non‐contact measurement method can reduce the risk to hydrologists when they are conducting measurements, particularly in high flow period. However, the original signals obtained by using GPR are very complex, different from studies in the past where the measured data were mostly interpreted by experts with special skill or knowledge of GPR so that the results obtained were less objective. This study employs Hilbert–Huang transform (HHT) to process GPR signals which are difficult to interpret by hydrologists. HHT is a newly developed signal processing method that can not only process the nonlinear and non‐stationary complex signals, but also maintain the physical significance of the signal itself. Using GPR with HHT, this study establishes a non‐contact stream cross‐section measurement method with the ability to measure stream cross‐sectional areas precisely and quickly. Also, in comparison with the conventional method, no significant difference in results is found to exist between the two methods, but the new method can considerably reduce risk, measurement time, and manpower. It is proven that the non‐contact method combining GPR with HHT is applicable to quickly and accurately measure stream cross section. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
79.
利用机器学习的方法,对14个周期HY-2A卫星高度计数据:风速、有效波高和海面高度差值进行训练,探究海况偏差和风速、有效波高之间的关系,创建海况偏差核函数非参数模型(NPSSB),并与参数模型中具有代表性的BM3、BM4模型进行对比。研究表明:(1)核函数NPSSB模型能够很好的反映SSB与U、SWH之间的关系,SSB与U呈二次函数关系,SSB与SWH呈反比例函数关系;(2)核函数NPSSB模型对SSB的模拟能力与训练数据集相关,数据量越多,模拟能力越好;(3)核函数NPSSB模型与BM3、BM4模型都存在0^-0.03 m的差值,随着风速和有效波高的增加,差值的绝对值越大。 相似文献
80.
以巴伦台钻孔倾斜及分量应变辅助观测气压数据为研究对象,运用相关及小波分析研究气压对巴伦台钻孔倾斜的影响特征。结果表明,气压对巴伦台钻孔倾斜影响表现为准线性关系,对NS向的影响大于EW向。气压对NS向影响的显著频段有2 048~8 192、32 768~65 536 min,对EW向影响的显著频段为2 048~8 192 min。探讨了气压对巴伦台钻孔倾斜的影响机制。 相似文献