Browsing by Author "Shan, HY"

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Construction use of abandoned soils
(1998-02-01)
Shan, HY
;
Meegoda, JN
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土木工程學系
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Department of Civil Engineering
Taiwan is a county under rapid development. Excavation in thousands of construction sites generated a huge amount of soils. In many cases, the soils are disposed randomly such that they are termed abandoned soils. A comprehensive study was conducted to investigate for reuse options of these soils: sub-grade construction, cement block production, structural concrete production, and asphalt concrete production. Five soils, representing predominant soil types in Taiwan were selected in this study. The compaction test results demonstrated that all five soils were suitable for subgrade construction. The compression tests for cement mortar showed that all soils produced mixes with strengths higher then 3.45 MPa and may be used to make cement blocks. The compressive strength test results of soil concrete samples showed that all soils except for the mix having 100% of soil No. 5 produced strengths higher than 17.25 MPa. The wet/dry durability test showed that the pozzolanic action of the soil concrete samples continued beyond 28 days and there seemed to be no detrimental effects. A comprehensive mix design was performed for each soil type and also developed a control mixture to test the use of abandoned soils in hot mix asphalt concrete. The study demonstrated that with proper design even clayey soils can be used to produce construction materials. (C) 1998 Elsevier Science B.V.
Effect of boundary conditions on the hydraulic behavior of geotextile filtration system
(2001-12-01)
Shan, HY
;
Wang, WL
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Chou, TC
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土木工程學系
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Department of Civil Engineering
There are several test methods available for studying the behavior of geotextile/soil filtration systems. However, there has not been a consensus on which one of these methods should be the most appropriate. In this research, gradient ratio (GR) tests and hydraulic conductivity (HCR) tests were performed to evaluate the effects of boundary conditions on the behavior of geotextile/soil filtration systems. The test results show that the hydraulic conductivity of the filtration systems decreased as the effective stress and hydraulic gradient increased. Furthermore, the hydraulic conductivity obtained from GR tests with a hydraulic gradient of 5 could be taken as the lower bounds for HCR test results. Therefore, it is suggested that the GR test can be used to obtain reasonable and conservative design parameters of the filtration systems. (C) 2001 Elsevier Science Ltd. All rights reserved.
Effect of gravel subgrade on hydraulic performance of geosynthetic clay liner
(2003-12-01)
Shan, HY
;
Chen, RH
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土木工程學系
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Department of Civil Engineering
The effect of a gravel subgrade on the hydraulic performance of GCLs is investigated. Laboratory test results show that the GCL specimens exhibit significant variation in thickness when compressed against gravel. The maximum and minimum thicknesses of the specimen were about 20 and 3 mm, respectively, after consolidation by an effective stress up to 138 kPa. However, the permittivity of GCLs remained very low. The permittivity of both needle-punched and adhesive-bonded geotextile-supported GCLs decreased with increasing confining stress, regardless of the type of subgrade materials. In general, larger particles led to more significant migration of bentonite. Nevertheless, there was no significant difference in the degree of bentonite migration between the two GCLs investigated. (C) 2003 Elsevier Ltd. All rights reserved.
Effect of hydrating liquid on the hydraulic properties of geosynthetic clay liners
(2002-02-01)
Shan, HY
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Lai, YJ
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土木工程學系
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Department of Civil Engineering
The engineering properties of geosynthetic clay liners (GCLs) are closely related to the chemistry of pore liquid. For applications in lining systems or cover systems of landfills, covers for remediation sites, and secondary containment systems, GCLs are likely to be permeated by more than one type of liquid. In this study, GCL specimens were hydrated and permeated with different liquids. The hydraulic conductivity of these GCL specimens was determined. The results showed that the hydraulic conductivity of GCLs was controlled by both hydrating and permeating liquid. In addition, even if GCLs were hydrated with aqueous phase liquids other than fresh water, they still have the ability to retard infiltration effectively. (C) 2002 Elsevier Science Ltd. All rights reserved.
Elearning for teachers on water environment education
(2005)
Lee, JG
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Su, F
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Chan, CL
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Shan, HY
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友訊交大聯合研發中心
This paper introduces a 3-year eLearning program for teachers on water environment education co-sponsored by the Ministry of Education, the Environmental Protection Agency, and the Water Resources Agency for the school teachers to disseminate the core knowledge on water environment to facilitate nationwide water education. This is the most extensive eLearning program for teachers on water environment education in Taiwan. A total of ninety hours of eLearning courses will be offered to the school teachers from 2004 to 2007. The first 30-hour eLearning courses offered in year 2004 attracted 1,576 participants, among which 56% are elementary school teachers. On the other hand, 80% of the participants are 21 to 40 years old. Seventy two percent of the participants joined the program by self-motivation to enrich their own knowledge, while another 25% participated in order to improve their teaching performance. With the success of the program in 2004, the Ministry of Education not only continues its support but also set a challenging goal to train more than 160,000 participants from now to year 2008.
Measurement of air permeability of geosynthetic clay liners
(2000-04-01)
Shan, HY
;
Yao, JT
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土木工程學系
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Department of Civil Engineering
Hydraulic barrier layer is the major component in the cover system of a modern landfill. The primary function of the barrier is to limit the amount of water infiltration. Another important function is to minimize the emission of landfill gas. In recent years, geosynthetic clay liners (GCLs) have been used in landfill covers as hydraulic barrier layer. However, in hot and arid areas the bentonite in GCLs may develop desiccation cracks. Before the cracks are closed upon wetting, significant amount of landfill gas might have already emitted into the atmosphere. To address this issue, air permeability tests were performed to assess the effectiveness of GCLs as a gas barrier. The results show that air can hardly pass through hydrated GCL specimens. However, the drying of GCLs induced significant increase of their air permeability. (C) 2000 Elsevier Science Ltd. All rights reserved.