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Self potential (SP) and electrical resistivity tomography (ERT) methods are used together with the results of groundwater samples hydrogeochemical analysis to assess the impact of the water leak from the landfill garbage site at NamSon located in Northern Hanoi on causing pollution to the surrounding environment and affecting geological structure. Selected survey area covers an area of 180 × 300 m lying in the low land of the NamSon site with a slope ranging about 8 m in direction NW–SE. There are three geophysical measurements lines denoted as T1, T2 and T3. Processing 180 SP data points has allowed to draw maps of equipotential epoch in the two periods in 2015 and 2016. The maps show four zones of SP positive anomalies with maximum amplitudes of about +20 mV where the groundwater flow direction is downward and five zones of SP negative anomalies with minimum values in a range from ?180 to ?260 mV where the groundwater flow direction is upward. Resistivity values of the subsurface layers of soils and rocks have been aquired from 2D inverse model for measuring ERT in March 2015 and March 2016. The results of the ERT allowed to define the low resistivity in the range 15–20 Ωm related to leachate plume from NamSon landfill site. Results of the physico-chemical analysis of groundwater samples from the existing six boreholes show increases in concentration of the measured pollutant parameters indicating contamination of the groundwater as a result of solid waste leachate accumulation. This result is affirmative evidence for the survey results by geophysical technique. The rapid decrease in quality of groundwater over the last year is probably due to the influence of the leachate from the NamSon landfill site. 相似文献
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İrfan Akca Thomas Günther Mike Müller‐Petke Ahmet T. Başokur Ugur Yaramanci 《Geophysical Prospecting》2014,62(2):364-376
Magnetic resonance sounding (MRS) has increasingly become an important method in hydrogeophysics because it allows for estimations of essential hydraulic properties such as porosity and hydraulic conductivity. A resistivity model is required for magnetic resonance sounding modelling and inversion. Therefore, joint interpretation or inversion is favourable to reduce the ambiguities that arise in separate magnetic resonance sounding and vertical electrical sounding (VES) inversions. A new method is suggested for the joint inversion of magnetic resonance sounding and vertical electrical sounding data. A one‐dimensional blocky model with varying layer thicknesses is used for the subsurface discretization. Instead of conventional derivative‐based inversion schemes that are strongly dependent on initial models, a global multi‐objective optimization scheme (a genetic algorithm [GA] in this case) is preferred to examine a set of possible solutions in a predefined search space. Multi‐objective joint optimization avoids the domination of one objective over the other without applying a weighting scheme. The outcome is a group of non‐dominated optimal solutions referred to as the Pareto‐optimal set. Tests conducted using synthetic data show that the multi‐objective joint optimization approximates the joint model parameters within the experimental error level and illustrates the range of trade‐off solutions, which is useful for understanding the consistency and conflicts between two models and objectives. Overall, the Levenberg‐Marquardt inversion of field data measured during a survey on a North Sea island presents similar solutions. However, the multi‐objective genetic algorithm method presents an efficient method for exploring the search space by producing a set of non‐dominated solutions. Borehole data were used to provide a verification of the inversion outcomes and indicate that the suggested genetic algorithm method is complementary for derivative‐based inversions. 相似文献
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In the western part of the city of Zagreb, Croatia, hydrogeochemical and isotopic investigations of the Samobor aquifer were
carried out with the aim of determining the differences in hydrogeochemical characteristics at increasing aquifer depths.
The aquifer comprises 40-m thick gravelly–sandy deposits, with lenses and interlayers of silt and clay. The analyses have
proven that with increasing aquifer depth, there are decreases in groundwater temperature and the values of electrical conductivity
and increases in the sodium, iron and manganese concentrations. The δ13C distribution shows an evident increase in biogenic carbon concentrations with increasing aquifer depth. The measured specific
14C activities showed that the deeper part of the aquifer is characterized by slow water exchange, while the shallower part
is influenced by current recharge, although the pumping wells located on the well-field downstream penetrate the aquifer fully.
A direct exchange of water from the Sava River and groundwater occurs in the near vicinity of the river. This exchange weakens
further away, while the difference in hydrogeochemical characteristics between the Sava River water and groundwater increases. 相似文献
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层状半空间中洞室对平面SH波的放大作用 总被引：1，自引：0，他引：1
利用间接边界元法,求解了弹性层状半空间中洞室对入射平面SH波的放大作用问题,并以基岩上单一土层中洞室对入射平面SH波的放大作用为例进行了数值计算分析。本文模型的特点之一是考虑了层状场地的动力特性,因而更接近于实际工程;特点之二是计算精度非常高。研究表明,层状半空间中洞室对波的放大作用与均匀半空间中情况有着本质的差别;层状半空间中洞室附近地表动力响应由土层动力特性和洞室对波的散射二者共同决定。土层动力特性不仅影响洞室附近地表位移的幅值,还会影响地表位移的频谱。在土层的前几阶共振频率附近,随着基岩与土层剪切波速比的增大,土层的影响随之增大,而随着土层厚度的增加,土层的影响随之减小,并逐渐趋于均匀半空间情况。 相似文献
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Amplification of in-plane seismic ground motion by group cavities in layered half-space (Ⅰ) 
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下载免费PDF全文 Amplification of in-plane seismic ground motion by underground group cavities in layered half-space is studied both in frequency domain and time domain by using indirect boundary element method (IBEM), and the effect of cavity interval and spectrum of incident waves on the amplification are studied by numerical examples. It is shown that there may be large interaction between cavities, and group cavities with certain intervals may have significant amplification to seismic ground motion. The amplification of PGA (peak ground acceleration) and its PRS (peak response spectrum) can be increased up to 45.2% and 84.4%, for an example site in Tianjin, under the excitation of Taft wave and El Centro wave; and group cavities may also affect the spectra of the seismic ground motion. It is suggested that the effect of underground group cavities on design seismic ground motion should be considered. 相似文献
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Bilohuščin Vladimír Uher Pavel Koděra Peter Milovská Stanislava Mikuš Tomáš Bačík Peter 《Mineralogy and Petrology》2017,111(4):643-658
Mineralogy and Petrology - Borate minerals of the ludwigite group (LGM) and szaibélyite in association with hydroxylclinohumite, clinochlore, a serpentine mineral, magnesian magnetite, spinel,... 相似文献