Analysis of the Influence of PVDs on Ground Consolidation by Using PLAXIS

• Main Authors: Yu-Chih Lo, 羅于智
• Other Authors: T.W Feng
• Format: Others
• Language: zh-TW
• Published: 2006
• Online Access: http://ndltd.ncl.edu.tw/handle/54262970419409783281

碩士 === 中原大學 === 土木工程研究所 === 94 === ABSTRACT Both preloading and Prefabricated Vertical Drain (PVD) are methods of ground improvements. Thy are widely used for improving soft clay. The purpose of this research is to simulate the behavior PVD in soft clay layer by using Finite Element code PLAXIS. The vertical drain function has not been built-in in PLAXIS. The main topics of study include: 1) the influence of PVD installation depth upon consolidation settlement; 2) the influence of PVD spacing on consolidation settlement; 3) the influence of smear effect on consolidation settlement; 4) the influence of well resistance on consolidation settlement; 5) case study of preloading and vertical drain in Second Bangkok International Airport (SBIA). The findings indicate: 1) provided the installation depth of PVD is over 85% of the thickness of improving ground, shortening the distance of PVD can increase the consolidation rate; but if the PVD installation depth is below 85% of the thickness of improving ground, there is no remarkable effect by shortening the spacing of PVDs; 2) concerning with the influence of smear effect, when kh/ks=2, the influence caused by increasing s is limited; but when the kh/ks =10, the influence caused by increasing s will increase; 3) the excess pore water pressure inside the PVD does not equal to zero, and the higher the well resistance , the higher is the excess pore water pressure; 4) the estimated consolidation settlement curve and excess pore water pressure dissipation curve of the case study are consistent with the observed curve.