The size effect on Geosynthetic-Encapsulated Sand Column Specimens
碩士 === 淡江大學 === 土木工程學系碩士班 === 97 === Granular columns were introduced into engineering practice to improve bearing capacity and reduce settlement in a weak or soft soil. This method is considered one of the most versatile and cost effective techniques for improving in-situ ground conditions. Most gr...
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| Format: | Others |
| Language: | zh-TW |
| Published: |
2009
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| Online Access: | http://ndltd.ncl.edu.tw/handle/63266714713457291981 |
| Summary: | 碩士 === 淡江大學 === 土木工程學系碩士班 === 97 === Granular columns were introduced into engineering practice to improve bearing capacity and reduce settlement in a weak or soft soil. This method is considered one of the most versatile and cost effective techniques for improving in-situ ground conditions.
Most granular columns that fail from bulging near the top are due to insufficient lateral support.Skirting the granular column by wrapping a geosynthetic liner around the top section of the column and enveloping the granular column in a membrane were proposed to strengthen the column. When vertical and coincident lateral deformations of the granular column occur under a vertical load, the encapsulating geosynthetic generates additional confining stress to the column.
Because the mechanical behavior of the granular material is usually controlled by the lateral confining pressure, the improvement in bearing capability from the geosynthetic-encapsulated granular column depends upon the mobilization of lateral or confining stresses exerted by the geosynthetic. The reinforcing effect of the granular column thus depends on the size of the specimen and the filled granular material.
Transferred the radial strain rate of sand column to the tensile rate of geosynthetic.Hyperbolic model was used to simulate tensile stress-strain relation of the geosynthetics.
Results from three geotextiles encapsulating sand specimen of three diameter size show: (1) Geotextile encapsulating sand column enhances the axial strength; the reinforced specimen exhibited significant apparent cohesive strength. (2)The size effect clearly increase with lower confining pressure; The small-size samples show significantly higher stress ratio.
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