Volume 18, Issue 70 (winter 2015)                   jwss 2015, 18(70): 47-58 | Back to browse issues page

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Dept. of Agric. Machinery Eng., College of Agri., Isf. Univ. of Technol., Isfahan, Iran , ahemmat@cc.iut.ac.ir
Abstract:   (10815 Views)

Flood irrigation after planting induces wetting and drying cycles in arable soils. For this reason, the effect of this process on load-bearing capacity (pre-compaction stress pc) of a fine textured soil (silty clay) was studied. In this research, large air-dry disturbed soil specimens were prepared and some of them were exposed to five wetting and drying cycles. Next, the large soil specimens with/without wetting and drying cycles were compressed under three preloads (0, 100 or 200 kPa) and then the centre section of the preloaded soil specimen was firstly submitted to a plate sinkage test (PST). Then immediately one cylindrical sample was cored for confined compression test (CCT). The results showed that for reconstructed soil samples without wetting-drying cycles, the predicted pc using PST didn't significantly differ from the applied preload. Therefore, the PST can be used to determine the load-support capacity of the tilled soils. In PST, with an increase in soil water content from 0.9PL to 1.1PL, the amount of over-prediction in pc decreased. However, wetting-drying process significantly increased over-prediction in pc at the same water content. Hence, soil compressibility does not simply depend on the actual soil water content but also on the previous history of water content changes (i.e., wetting-drying cycles).

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Type of Study: Research | Subject: Ggeneral
Received: 2015/03/9 | Accepted: 2015/03/9 | Published: 2015/03/9

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