Browsing by Author "Chou, Shih-Hsun"

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Physical simulation of aquifer compression due to groundwater fluctuation
(2017-12-14)
Chang, Wen-Jong
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Chou, Shih-Hsun
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Huang, An-Bin
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土木工程學系
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Department of Civil Engineering
To investigate the compression of granular aquifer induced by fluctuations of pore pressure, series of repeated pore pressure induced loading-unloading tests on specimens made of Ottawa sand mixed with mica were conducted in a K-o-triodal consolidation system. To simulate the stress paths in the field, the vertical displacements of soil specimens were monitored while maintaining a constant total vertical stress and applying sinusoidal fluctuations of pore pressure to specimens under K-o conditions. Shakedown theory is applied to interpret the testing data. The paper describes the laboratory setup, test procedure and findings from the test results. The results reveal that a shakedown behavior existed in saturated granular specimens and the accumulated permanent axial strains are 5 to 56 times of the values for conventional, monotonic loading. The finding evidently proves the significance of aquifer compression to ground subsidence due to repeated ground water fluctuations.
Simplified monitoring and warning system against rainfall-induced shallow slope failures
(2018-10-01)
Wang, Chien-Chih
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Chang, Wen-Jong
;
Huang, An-Bin
;
Chou, Shih-Hsun
;
Chien, Yu-Chun
A system that involves the use of a low-cost microelectromechanical system (MEMS)-based sensor stick and soil-water characteristic curve (SWCC) inferred from grain-size distribution was developed to assess the factor of safety against rainfall-induced shallow slope failure. The system allows water content at multiple depths to be monitored in the field. The corresponding suction and factor of safety against infinite slope failure are derived based on the estimated SWCC. The new system circumvents the use of tedious and often costly field as well as laboratory procedures while providing a quantitative slope stability assessment on a real-time basis. The paper introduces the background of the new development and describes the application of the sensor stick system in a field test.