SW—Soil and Water: Construction of an Artificial Perched Watertable, Part 2: Soil Cavity Production by Air pressure

✍ Scribed by K. Araya; G. Guo

• Book ID: 102966007
• Publisher: Elsevier Science
• Year: 2002
• Tongue: English
• Weight: 527 KB
• Volume: 82
• Category: Article
• ISSN: 1537-5110
• DOI: 10.1006/bioe.2001.0041

✦ Synopsis

By constructing an artificial perched watertable which is a horizontal and cylindrical soil cavity with a diameter of 3 m and a height of 0Á3 m, at a depth of about 0Á8 m from the soil surface in the fields, it was envisaged that the runoff caused in the summer could preferably be held in this layer and, hence, the excess moisture loss could be prevented. The water in the artificial soil cavity could be used as capillary water for plants germinating in the spring. The soil failure experiments by the injection of high-pressure air were conducted to form the artificial perched watertable. In this paper, the size of the underground soil cavity produced by the high-pressure air was determined. The gas energy and gas pressure required for the proper size of the soil cavity were also evaluated.

The results show that the energy required for soil-cavity production significantly increased with the larger radius of the soil cavity, the energy of the soil-cavity production being 100 kJ for a cavity radius of 1 m compared with 1000 kJ for a cavity radius of 2 m. When the design point of the soil-cavity radius is 1Á5 m (the diameter of the soil cavity is 3Á0 m), the required energy is about 300 kJ. The height of the underground soil cavity produced by the high-pressure air injection was always 0Á3 m regardless of the working depth of the injector. The radius of the soil cavity produced was 1Á5 m on average when the working depth of the injector was more than 0Á6 m. When a soil cavity is produced at a depth of 0Á8 m in the field of the meadow soil or planosol in China, the tensile strength of 20 kPa is more than the earth pressure of 14 kPa and hence, the air pressure in the charge tank should be at least more than 20 kPa.