The Consolidation Behavior of Soft Clay after Setting Prefabricated Vertical Drainage

• Main Authors: Liu, Wei Pin, 劉維斌
• Other Authors: Chang Huei Wein
• Format: Others
• Language: zh-TW
• Published: 1998
• Online Access: http://ndltd.ncl.edu.tw/handle/38251052641818977984

碩士 === 國立中央大學 === 土木工程學系 === 86 === To improve the bearing capacity of soft soils, preloading is the one of most preferable methods. Since most soft soils have very low permeability, dissipation of excess pore water pressure during preloading takes time. Therefore, sand-drain-piles and prefabricated vertical drainage (PVD) methods have been developed to accelerate consolidation process. Essentially, these methods shorten the length of drainage paths from the thickness of clay layers to the spacing of drain wells.The research of the consolidation behavior accelerated by PVD on soft clay divides into three parts: I, The settlement analysis of stratum driven by PVD; II, To study the properties of stratum consolidation after PVD constructed; III, Indoor pit test. According to the results of laboratory experiments, the settlement of soil layers is influenced by the discharge capacity of PVD. Smearing, well resistance, filter blinding, and clogging are the factors influencing the function of PVD, which decrease the permeability of soils and the discharge capacity of PVD. The factors should have to be taken into account in the future.Finally, the results of indoor pit test which includes two zones－ improved zone and untreated zone-reveal that, after setting the load on the pit the settlement of the improved zone is larger than the untreated zone, and the pore water pressure and the earth pressure increase rapidly at the both zones. In the next day, the pore water pressure and earth pressure in improved zone decrease rapidly, but not in the untreated zone.