scholarly journals Hydrogeological Characterization of Coastal Aquifer on the Basis of Observed Sea Level and Groundwater Level Fluctuations: Neretva Valley Aquifer, Croatia

Water ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 348
Author(s):  
Veljko Srzić ◽  
Ivan Lovrinović ◽  
Ivan Racetin ◽  
Fanito Pletikosić
Keyword(s):  
Sea Level ◽  
Data Availability ◽  
Problem Analysis ◽  
Clay Layer ◽  
In Situ Tests ◽  
Specific Storage ◽  
Hydrogeological Parameters ◽  
Area Of Interest

Hydrogeological data availability is often limited to local areas where usual in situ tests or methods are applied (slug/bail or pumping tests, Electrical Resistivity Tomography (ERT)). Because most problems (e.g., saltwater intrusion mitigation) require problem analysis on larger scales (catchment or sub catchment), hydrogeological identification of global character is preferable. This work leads to the determination of aquifer hydrogeological parameters on the basis of observed sea level, groundwater piezometric head found inland, and barometric pressure. When applied to observed signals, the approach led efficiently to final hydrogeological characterization. After identification of dominant tidal constituents from observed signals, barometric efficiency was successfully determined. Following available information on geological settings, an appropriate conceptual model was applied and updated to count for polychromatic signals. Final determination of hydrogeological parameters relied on root mean square error (RMSE) minimization and led to determination of (i) presence of three stratigraphic units: unconfined sandy aquifer on the top, a confining layer made of clay, and a confined gravel layer; (ii) existence of the clay layer under the sea with a total length of 1400 m; (iii) a clay layer has been identified as confining one by both spectral analysis and determined leakance value; and (iv) estimated confined aquifer specific storage ranging from 2.87 × 10−6 to 4.98 × 10−6 (m−1), whereas hydraulic conductivity ranged from 7.0 × 10−4 to 7.5 × 10−3 (m s−1). Both range intervals corresponded to previous in situ findings conducted within the area of interest.

scholarly journals Determination of Mining-Induced Changes in Hydrogeological Parameters of Overburden Aquifer in a Coalfield, Northwest China: Approaches Using the Water Level Response to Earth Tides

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Qingyu Xu ◽  
Guangcai Wang ◽  
Xiangyang Liang ◽  
Shen Qu ◽  
Zheming Shi ◽  
...  
Keyword(s):  
Water Level ◽  
Northwest China ◽  
Earth Tides ◽  
Well Water ◽  
Coal Face ◽  
Specific Storage ◽  
Hydrogeological Parameters ◽  
Well Water Level

The determination of changes in hydrogeological properties (e.g., permeability and specific storage) of aquifers disturbed by mining activity is significant to groundwater resource and ecological environment protection in coal mine areas. However, such parameters are difficult to continuously measure in situ using conventional hydrogeological methods, and their temporal changes associated with coal mining are not well understood. The response of well water level to Earth tides provides a unique probe to determine the in situ hydrogeological parameters and their variations. In this study, the tidal responses of well water level were employed to characterize the changes in hydrogeological parameters of the overburden aquifer induced by longwall mining in a coalfield, northwest China. Based on the long-term hourly recorded water level data, two analytical models were used to determine the temporal changes of permeability and specific storage of the overburden aquifer. The results showed that the hydrogeological parameters changed with the longwall coal face advance. When the longwall coal face approached the wells, the aquifer permeability increased several to dozens of times, and the response distance ranged from 80 m to 300 m. The specific storage decreased before the coal face reached wells and recovered after the coal face passed. The results of this study indicate that the hydrogeological parameter changes induced by coal mining are related to the location of the well relative to the coal face and the stress distribution in the overburden aquifer. This study revealed the changes in permeability and specific storage associated with the mining disturbance which could have great significance for quantitative assessment of the impact of mining on overburden aquifer.

scholarly journals Laboratory and In Situ Determination of Hydraulic Conductivity and Their Validity in Transient Seepage Analysis

Water ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1131
Author(s):  
Soonkie Nam ◽  
Marte Gutierrez ◽  
Panayiotis Diplas ◽  
John Petrie
Keyword(s):  
Hydraulic Conductivity ◽  
Field Measurements ◽  
Natural Soil ◽  
In Situ Tests ◽  
Seepage Analysis ◽  
Soil Deposits ◽  
Seepage Modeling ◽  
Sample Disturbance

This paper critically compares the use of laboratory tests against in situ tests combined with numerical seepage modeling to determine the hydraulic conductivity of natural soil deposits. Laboratory determination of hydraulic conductivity used the constant head permeability and oedometer tests on undisturbed Shelby tube and block soil samples. The auger hole method and Guelph permeameter tests were performed in the field. Groundwater table elevations in natural soil deposits with different hydraulic conductivity values were predicted using finite element seepage modeling and compared with field measurements to assess the various test results. Hydraulic conductivity values obtained by the auger hole method provide predictions that best match the groundwater table’s observed location at the field site. This observation indicates that hydraulic conductivity determined by the in situ test represents the actual conditions in the field better than that determined in a laboratory setting. The differences between the laboratory and in situ hydraulic conductivity values can be attributed to factors such as sample disturbance, soil anisotropy, fissures and cracks, and soil structure in addition to the conceptual and procedural differences in testing methods and effects of sample size.

Determination of Hydrogeological Parameters of Aquifer Using the Air Compressor Pumping

2013 ◽  
Vol 448-453 ◽  
pp. 3989-3992
Author(s):  
Xue Jiang ◽  
Xiu Juan Liang ◽  
Chang Lai Xiao ◽  
Chuan Du ◽  
Zhong Kai Wang
Keyword(s):  
Hydraulic Conductivity ◽  
Water Level ◽  
Oil Shale ◽  
Pumping Test ◽  
Comprehensive Analysis ◽  
Graphic Method ◽  
Air Compressor ◽  
Hydrogeological Parameters

When the buried depth of water level is very large, the air compressor is used in pumping test. In the limited conditions, the value of the water level was not measured, but the recovery value of water level could be measured. In this case, the sp value of the water level drawdown was not able to be measured accurately when the pumping test stopped. So the hydraulic conductivity of aquifer could only be determined according to the linear graphic method of the water level recovery test. However, water level recovery characteristics of each period were not the same, and the raising rate of water level were not equal. Thus, there was a deviation when the hydraulic conductivity was solved with the linear graphic method. According to the existing data, the thesis combined the water level recovery fitting of the entire curve fitting with Dupuit formula of artesian well, determining the sp value and hydrogeological parameters of aquifer. After comprehensive analysis, the parameters obtained are more reasonable, which can provide a good reference for in-situ mining of oil shale in this area.

scholarly journals Neural networks and principle component analysis approaches to predict pile capacity in sand

2018 ◽  
Vol 149 ◽  
pp. 02025 ◽  
Author(s):  
A Benali ◽  
A Nechnech ◽  
B Boukhatem ◽  
M N Hussein ◽  
M Karry
Keyword(s):  
Neural Networks ◽  
Bearing Capacity ◽  
Driven Piles ◽  
In Situ Tests ◽  
Pile Capacity ◽  
Significant Development ◽  
Pca Method ◽  
Main Component

Determination of pile bearing capacity from the in-situ tests has developed considerably due to the significant development of their technology. The project presented in this paper is a combination of two approaches, artificial neural networks and main component analyses that allow the development of a neural network model that provides a more accurate prediction of axial load bearing capacity based on the SPT test data. The retropropagation multi-layer perceptron with Bayesian regularization (RB) was used in this model. This was established by the incorporation of about 260 data, obtained from the published literature, of experimental programs for large displacement driven piles. The PCA method is proposed for compression and suppression of the correlation between these data. This will improve the performance of generalization of the model.

Determination of horizontal geostatic stress in clay with self-bored pressuremeter

1988 ◽  
Vol 25 (3) ◽  
pp. 559-573 ◽  
Author(s):  
M. G. Jefferies
Keyword(s):  
Key Words ◽  
Image Matching ◽  
The Self ◽  
In Situ Tests ◽  
Extended Theory ◽  
Computer Aided ◽  
Modelling Procedure

The Gibson–Anderson theory for interpretation of pressuremeter data in clay is extended to include the unloading part of the test for the particular circumstances that prevail with a self-bored pressuremeter (SBP). Incorporation of the extended theory in a computer-aided modelling procedure allows horizontal geostatic stress to be unambiguously determined from SBP data by image matching irrespective of imperfections in the self-boring process. The procedure is illustrated by example on a previously reported test carried out in Beaufort Shelf clay. Key words: clay, in situ tests, self-bored pressuremeter, K0.

scholarly journals PROPOSTA DE APLICAÇÃO DE RESULTADOS DE SONDAGENS COM MARTELO LEVE (DPL) NO CAMPO EXPERIMENTAL DA UNIFOR EM PROJETOS DE FUNDAÇÕES PARA PEQUENAS CARGAS [ Proposal for the Application of Dynamic Probing Light (DPL) Results in the Experimental Field of UNIFOR in Foundations Projects for Small Loads ]

2018 ◽  
Vol 14 (2) ◽  
Author(s):  
Marcos Fábio Porto de Aguiar ◽  
Fernando Feitosa Monteiro ◽  
Francisco Heber Lacerda de Oliveira ◽  
Yago Machado Pereira de Matos
Keyword(s):  
Bearing Capacity ◽  
Standard Penetration Test ◽  
Coefficient Of Determination ◽  
Deep Foundations ◽  
Penetration Test ◽  
In Situ Tests ◽  
Foundation Design ◽  
Experimental Field

RESUMO: Em meio aos diversos métodos utilizados no Brasil para determinação da capacidade de carga de fundações, a grande maioria parte do índice de resistência à penetração (NSPT). Para o caso de pequenas edificações, devido a fatores geralmente econômicos, a experiência ou a prática regional costumam prevalecer. Sendo assim, são elaborados, muitas vezes, projetos sem um procedimento de cálculo fundamentado em parâmetros comprovados por ensaios geotécnicos, podendo ocasionar problemas na edificação, como recalques excessivos, ou, até mesmo, comprometer a segurança da estrutura. Dessa forma, técnicas mais simples e de baixo custo, como o DPL (Dynamic Probing Light), podem ser uma opção para situações de pequenas cargas, viabilizando projetos fundamentados em ensaios in situ. Partindo de investigações com o DPL, este trabalho tem o objetivo de dimensionar fundações superficiais e profundas para edificações de pequeno porte através de algumas das principais metodologias disponíveis na literatura e verificar a sua eficiência. Por meio de resultados de campanhas de sondagens SPT (Standard Penetration Test) e DPL no campo experimental da Universidade de Fortaleza (UNIFOR), determinou-se a capacidade de carga de fundações superficiais e profundas fazendo aplicação dos índices NSPT e NSPT equivalente obtido pela correlação com o DPL. Identificou-se que essa correlação apresentou coeficiente de determinação satisfatório entre os parâmetros obtidos nos ensaios SPT e DPL para o terreno em questão, mostrando-se o DPL ser uma alternativa pertinente, em termos técnicos para projetos de fundações de obras de pequeno porte.ABSTRACT: Among the various methods used in Brazil of the determination of the bearing capacity on foundations, most part uses the standard penetration resistance (NSPT). For small constructions, due to economic factors generally, experience or regional practice usually prevails. Thus, projects without a reasoned calculation procedure in parameters supported by geotechnical tests are often designed, and may cause problems in the building, as excessive settlements, or even compromise the safety of the structure. In this way, simple and low cost techniques such as DPL (Dynamic Probing Light) may be an option for small loads situations, enabling projects based on in situ tests. This paper proposes to calculate the dimensions of shallow and deep foundations for small constructions and check its efficiency using DPL tests. Through the results of SPT (Standard Penetration Test) and DPL tests in the experimental field of the University of Fortaleza (UNIFOR), the determination of the bearing capacity in shallow and deep foundations was done using NSPT index and equivalent NSPT index obtained by the correlation with DPL. A correlation with satisfactory coefficient of determination was obtained between SPT and DPL tests parameters for the analyzed field, showing up the DPL as an appropriate alternative in technical terms for foundation design of small constructions.

scholarly journals Pengaruh Perbedaan Kedalaman Terhadap Fitoplankton dan Zooplankton Di Perairan Pulau Panjang, Jepara

2019 ◽  
Vol 8 (2) ◽  
pp. 181-188
Author(s):  
Deftika Mulyawati ◽  
Raden Ario ◽  
Ita Riniatsih
Keyword(s):  
Sea Level ◽  
Sea Water ◽  
Mesh Size ◽  
Active Method ◽  
Limited Mobility ◽  
Relationship Of ◽  
The Relationship ◽  
Ship Speed

Plankton merupakan sebuah kelompok organisme yang hanyut bebas di dalam lautan. Plankton dapat dibagi menjadi dua golongan, yaitu fitoplankton dan zooplankton. Penelitian ini bertujuan untuk mengetahui hubungan dari kelimpahan fitoplankton dan zooplankton berdasarkan perbedaan kedalaman di perairan timur Pulau Panjang Kabupaten Jepara. Pengambilan sampel dilakukan dengan metode aktif yaitu dengan menarik plankton net dengan mata jaring ukuran 45µ untuk fitoplankton dan 150µ untuk zooplankton. Penarikan dilakukan menggunakan kapal selama 3-5 menit dengan kecepatan kapal 0,67 m/s pada lokasi penelitian. Penentuan stasiun penelitian berdasarkan pada perbedaan kedalaman. Kedalaman air laut yang digunakan pada saat pengambilan sampel ini adalah stasiun 1 dengan kedalaman 0 m atau permukaan air laut, stasiun 2 dengan kedalaman 1-2 m dari permukaan air laut, dan stasiun 3 dengan kedalaman 3-4 m dari permukaan air laut. Pengukuran kualitas perairan dilakukan secara in situ bersamaan dengan pengambilan sampel dilakukan. Hasil dari penelitian ini didapatkan komposisi fitoplankton sebanyak 13 genus dengan kelimpahan berkisar antara 3844,19-10869,80 individu/m3. Komposisi zooplankton di perairan didapatkan sebanyak 12 genus dengan kelimpahan berkisar antara 838,77-3250,24 individu/m3. Hubungan kelimpahan antara zooplankton dan fitoplankton di perairan ini termasuk kedalam golongan hubungan korelasi positif Plankton is a group that drifts freely in the ocean. Plankton has limited mobility. Plankton can be divided into two groups, namely phytoplankton and zooplankton. This study aims to determine the relationship of the abundance of phytoplankton and zooplankton based on rates in the east of Panjang Island, Jepara Regency. Sampling is done by the active method, namely by pulling the plankton net with a mesh size of 45µ for phytoplankton and 150µ for zooplankton. Withdrawals carried out by a ship for 3-5 minutes with a ship speed of 0.67 m/s at the study site. Determination of research stations based on differences in depth. The depth of sea water used during sampling is station 1 with a depth of 0 m or sea level, station 2 with a depth of 1-2 m from sea level, and station 3 with a depth of 3-4 m above sea level. Measurements of water quality were carried out in situ together with sampling. The results of this study obtained phytoplankton compositions as many as 13 genera with abundance ranging from 3844.19-10869.80 individuals/m3. The composition of zooplankton in the waters obtained as many as 12 genera with abundance ranging from 838.77-3250.24 individuals/m3. The relationship of abundance between zooplankton and phytoplankton in these waters is included in the group of positive correlation.

scholarly journals The analysis on the correlation parameters of the embankment compaction under in situ conditions

2013 ◽  
Vol 12 (3) ◽  
pp. 097-104
Author(s):  
Maciej Kumor ◽  
Łukasz Kumor ◽  
Joanna Farmas
Keyword(s):  
Particle Size ◽  
In Situ Tests ◽  
Geotechnical Assessment ◽  
In Situ Conditions ◽  
Wide Range ◽  
Correlation Parameters ◽  
And Control

Geotechnical assessment of the implementation correctness of a road embankment wide range of issues, among which important selection and control of the quality of the earthworks are extremely significant. The article presents results of in situ tests determining correlations between the depending parameters defined by a static plate – VSS test – E1 and E2, and obtained from the study LFG Dynamic Load Plate. Studies indicate that the determination of the correlation between the parameters characterizing the particle size distribution (Cc, Cu, D10, D20, D30, D60), and the compaction parameters obtained by examining the compaction of sand embankment (Evd, E1, E2, I0) is physically complex and hence extremely difficult. 

scholarly journals Improvement of Gas Drainage Efficiency via Optimization of Sealing Depth of Cross-Measure Boreholes

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Pu Li ◽  
Zhiheng Cheng ◽  
Liang Chen ◽  
Hongbing Wang ◽  
Jialin Cao
Keyword(s):  
Stress Concentration ◽  
Drainage System ◽  
Stress Concentration Zone ◽  
Concentration Zone ◽  
Air Leakage ◽  
In Situ Tests ◽  
Gas Drainage ◽  
Drainage Borehole

The sealing depth of a gas-drainage borehole is critically important as it directly affects the efficiency of the whole drainage system. In order to determine the shortest reasonable sealing depth, in this paper, a theoretical drainage model using different sealing depths was proposed. Based on theoretical analysis presented, two parts of the fractures system surrounding the drainage borehole were proposed, i.e. the fractures induced by roadway excavation and the fractures induced by borehole drilling. A series of geological in-situ tests and simulations research were conducted to determine the stress and fracture distributions in the surrounding rock of the borehole. The depths of crushing zones, plastic zones and stress concentration zones were determined as 5 m, 2 m and 12 m, respectively. Meanwhile, stress simulation shows that the depth of the stress concentration zone was 12 m from the roadway wall and the stress peak was located at the depth of 8 m, which can be verified by the results of drilling penetration velocity analysis. To determine the optimum sealing depth, gas drainage holes with different sealing depths were drilled in the field. The field results revealed that the crushing zones were the main area for air leakage, and the stress concentration induced by roadway excavation assisted in the reduction of air leakage. Therefore, the optimized sealing depth should both cover the plastic zone and the stress concentration zone. The research achievements can provide a quantitative method for the determination of optimum sealing depth in cross-measure drainage boreholes.

scholarly journals Determination of the Undrained Shear Strength of Sensitive Clay Using Some Laboratory Soil Data

2021 ◽  
Vol 8 (1) ◽  
pp. 14
Author(s):  
Tahar Ayadat
Keyword(s):  
Shear Strength ◽  
Soil Properties ◽  
Bearing Capacity ◽  
Fine Particles ◽  
Undrained Shear Strength ◽  
Clay Layer ◽  
In Situ Tests ◽  
Sensitive Clay ◽  
Undrained Shear

The undrained shear strength is a paramount parameter in determining the consistency and the ultimate bearing capacity of a clay layer. This resistance can be determined by in-situ tests, such as the field vane test or by laboratory tests, including the portable vane test, the triaxial, the simple compression test, and the consistency penetrometer test (i.e. the Swedish cone). However, the field vane test and the Swedish cone are the most commonly test used by geotechnical experts. In this paper, relationships between the field undrained shear strength of sensitive clay and some laboratory soil properties were developed. The soil properties consisted of the percentage of fine particles (less than 2 µm), the moisture content and the Atterberg limits. Furthermore, a correlation was proposed associating between the undrained shear strength of sensitive clay as obtained by the field vane test and the laboratory cone penetration test (Swedish cone). In addition, some applications of the proposed correlation on some geotechnical problems were included, such as the determination of the consistency and the bearing capacity of a clay layer. Comparison of the results of the developed correlations with the experimental results of the present investigation and the results reported in the literature show acceptable agreement.

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