The sedimentation mechanism and shear strength of cement treated sand in water

• Main Authors: Shao-min Chang, 張邵民
• Other Authors: Huei-wen Chang
• Format: Others
• Language: zh-TW
• Published: 2009
• Online Access: http://ndltd.ncl.edu.tw/handle/81322735990785887084

碩士 === 國立中央大學 === 土木工程研究所 === 97 === Sandy soil layers formed by hydraulic filling are usually very loose. It may cause liquefaction problems during earthquake. If a kind of non-liquefaction soil material mixed with cement were used in the process of backfill, the latter soil treatment will not be necessary for preventing liquefaction. In order to avoid the separation of cement particles from cement treated sands during the backfilling in water, the cement treated sand was improved by adding various types of coagulant (cation and anion of polyacrylamide) to simulate the backfill of free sedimentation mode. This research focused on the sedimentation mechanism and discussed the effects of cement treated sands with coagulant in water. A series of unconfined compression tests and dynamic triaxial tests were carried out by adding various contents of coagulant and cement. According to the experimental results, the unconfined compression strength of sand tended to be improved while the cement content was increased. The types of content and coagulant influenced the unconfined compression strength of sand. Moreover, the cyclic resistance would be significantly increased by adding 344 mg/kg coagulant, 6 % cement. Therefore, cation and anion of polyacrylamide and cement can improve the dynamic properties of sands.