scholarly journals About the influence of the injection mode on tracer test results

2020 ◽  
pp. 11-17
Author(s):  
S. Brouyère ◽  
C. Rentier
Keyword(s):  
Tracer Test ◽  
Test Results ◽  
Injection Mode

Hydraulic Conductivity and Scale Effects Investigation in Basalt in the Dam Area of Xiluodu Hydroelectric Station, Jinshajiang River, China

2013 ◽  
Vol 405-408 ◽  
pp. 2123-2129
Author(s):  
Yuan Yao Li ◽  
Rong Lin Sun ◽  
Ren Quan Chen
Keyword(s):  
Hydraulic Conductivity ◽  
Scale Effects ◽  
Fractured Rock ◽  
Water Pressure ◽  
Hydroelectric Station ◽  
Tracer Test ◽  
Test Results ◽  
Hydraulic Test ◽  
Water Seepage ◽  
Pressure Tests

Hydraulic conductivity (K) and scale effects in basalt in the dam area of Xiluodu hydroelectric station were investigated by three kinds of field hydraulic tests with different test scale, 2608 water pressure tests in single borehole, 54 water seepage tests in adit and groundwater tracer test. Statistical results show the high heterogeneity of fractured rock and K difference between two neighboring test intervals are often more than two orders of magnitude. However, there is a strong decreasing trend of hydraulic conductivity with the increase of vertical depth. Moreover, these three kinds of hydraulic test results demonstrate that hydraulic conductivity increases with the increase of test scale in heterogeneous basalt and the heterogeneous degree of K decreases with the increase of test scale. K from water seepage test in adit, with the test scale of 1-2 m, is dispersed from 0.00024 m/d to 3.46 m/d. K from water pressure test in single borehole, with the test scale of 4-7 m, is 0.0002-1.04 m/d. K from groundwater tracer test, with the test scale of 70-145 m, is concentrated between 0.46 m/d and 2.1 m/d. High heterogeneity of fractured rock and multi-level of fractures are thought as the major reason resulted in scale effects of hydraulic conductivity.

scholarly journals Groundwater circulation and earthquake-related changes in hydrogeological karst environments: a case study of the Sibillini Mountains (central Italy) involving artificial tracers

2020 ◽  
Vol 28 (7) ◽  
pp. 2409-2428 ◽  
Author(s):  
T. Nanni ◽  
P. M. Vivalda ◽  
S. Palpacelli ◽  
M. Marcellini ◽  
A. Tazioli
Keyword(s):  
Central Italy ◽  
Tracer Tests ◽  
Tracer Test ◽  
Breakthrough Curves ◽  
Water Circulation ◽  
Test Results ◽  
Flow Rates ◽  
Aquifer System ◽  
Structural Framework ◽  
Groundwater Circulation

Abstract Using artificial tracer tests, this study confirms the presence of a single basal aquifer feeding the springs in the wide and complex hydrogeological boundary of the Sibillini Mountains of central Italy. The tracer was introduced into the sinkhole of the Castelluccio di Norcia plain. The tracer test results, observed at the studied springs, highlight the changes induced by the 2016/2017 earthquake in the water circulation of the aquifer system. In particular, the seismic events increased the hydraulic conductivity of the basal aquifer, with a consequent increase in the springs’ flow rates at the western hydrogeological boundary and a decrease in the flow rates at the eastern Adriatic hydrogeological boundary. This phenomenon is in accordance with the hydro-structural framework of the area. The study also investigated the relation between groundwater circulation and tracer behaviour in the springs during the pre- and post-earthquake periods. The tracer test results led to the formulation of hypotheses about water circulation of the area. The trend of the tracer breakthrough curves demonstrates that the upper portion of the basal aquifer is characterised by fast water circulation similar to that in the epiphreatic area of karst aquifers, while a slow circulation due to fissures with interconnected drains occurs in the deepest portion of the aquifers. The obtained results highlight how tectonics and karst can affect the hydrogeological setting of the Apennine carbonate chain; in particular, the seismicity of central Italy may alter groundwater circulation for a long period of time when great magnitude earthquakes occur.

scholarly journals Biased Estimation of Groundwater Velocity from a Push-Pull Tracer Test Due to Plume Density and Pumping Rate

Water ◽  
2019 ◽  
Vol 11 (8) ◽  
pp. 1558 ◽  
Author(s):  
Hong-Hyun Kim ◽  
Eun-Hee Koh ◽  
Seong-Sun Lee ◽  
Kang-Kun Lee
Keyword(s):  
Numerical Simulations ◽  
Drift Time ◽  
Tracer Tests ◽  
Tracer Test ◽  
Linear Velocity ◽  
Test Results ◽  
Groundwater Velocity ◽  
Pumping Rate ◽  
Laboratory Test Results ◽  
Pumping Rates

The single-well push-pull tracer test is a convenient and cost-effective tool to estimate hydrogeological properties of a subsurface aquifer system. However, it has a limitation that test results can be affected by various experimental designs. In this study, a series of laboratory-scale push-pull tracer tests were conducted under various conditions controlling input tracer density, pumping rate, drift time, and hydraulic gradient. Based on the laboratory test results, numerical simulations were performed to evaluate the effects of density-induced plume sinking and pumping rate on the proper estimation of groundwater background linear velocity. Laboratory tests and numerical simulations indicated that the actual linear velocity was underestimated for the higher concentration of the input tracer because solute travel distance and direction during drift time were dominantly affected by the plume density. During the pulling phase, reasonable pumping rates were needed to extract the majority of injected tracer mass to obtain a genuine center of mass time (tcom). This study presents a graph showing reasonable pumping rates for different combinations of plume density and background groundwater velocity. The results indicate that careful consideration must be given to the design and interpretation of push-pull tracer tests.

Studies on Sealing Performance of Clay Plug by the Tunnel Sealing Experiment

2006 ◽  
Vol 932 ◽  
Author(s):  
S. Kawakami ◽  
T. Fujita ◽  
K. Masumoto ◽  
M. Yui
Keyword(s):  
Numerical Analysis ◽  
Tracer Test ◽  
Test Results ◽  
Transport Pathway ◽  
Sealing Performance ◽  
In Situ Experiments ◽  
Total Data ◽  
Underground Research Laboratory ◽  
Canada Limited

ABSTRACTTo establish sealing performance suitable for geological environmental conditions of Japan, it is necessary to obtain basic data related for the sealing function through laboratory and in-situ experiments. These data are to be used for practical design and to establish the method for analysis of the sealing performance.Japan Nuclear Cycle Development Institute (JNC) has joined the international project, the Tunnel Sealing Experiment (TSX), to demonstrate the sealing performance of full scale plugs in-situ, and to develop analytical method of the sealing performance of the plugs at Underground Research Laboratory (URL) of Atomic Energy of Canada Limited (AECL) in Canada [1]. This experiment is in the final stage and fundamental data for the sealing function of clay and concrete plugs have been obtained.This paper presents the total data handling and interpretation of the sealing experiment, as well as the numerical analysis and interpretation for clay plug performance based on tracer test results. As a result of the numerical analysis, the sealing performance of the clay plug was confirmed and it was shown that the excavation disturbed zones (EDZ) around the clay plug and the tunnel could be a dominant transport pathway for radionuclides.

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