【正文】 atio are obtained from this value. Moreover, the ? value can also be calculated as well as the average consolidation coefficient Cv. Proposed Design Philosophy, Construction, Installation and Monitoring Method As per of Section of ITB 4 4 According to the requirement of the owner, the static peration test should be carried out at the 10 specified points and the peration instruments should be buried through the whole depth of the pressible soil layers. Preliminary geotechnical design for vertical drains and soil discharge The type SPB plastic drainage plate is adopted as the vertical drains in this project. The vertical drains would be distributed accordingly to an equilateral triangle pattern. Based on our previous experiences of soft soil improvement in the Mekong delta area and according to the work requirements from the project, we believe that the bearing capacity of processed foundation soil can be reached. However, it is arduous to reach the same requirement for the deformation. It needs a paratively long period to attain a stable state of foundation soil settlement. In accordance with the tender document for the general area, the filling materials have to be well pacted to meet the building standard. Still, there are no relevant requirements of bearing capacity, so the inserting depth of the vertical drains should be less than the thickness of the soft soil layers to avoid the occurrence of extreme settlement. In the opposite case, that would imply a large additional quantity of loading materials and a soaring construction cost. Combining vacuum technique with loading method, the different requirements of bearing capacity of process area can be firmly met. Obviously, the airtight condition during vacuum prepression is a critical factor to ensure a sufficient vacuum level. The depth of vertical drains in the process area is estimated to be 10m to ensure that the end of vertical drains is within the soft soil layer which is about 14m depth. This will avoid any leakage from lower sand layer. The interval of the vertical drains in general area: L = For process area: f =5 t/m2, L = . f = t/m2, L = . f =10 t/m2, L = . The initial geotechnical design is shown in two tables: “ Geotechn ical Design of Vacuum Prepression Method of Process Area” and “ Geotechnical Design of Preloading Method of General Area” in page 11, 12. 5. Proposed vertical drains materials The SPB0II type vertical drain is adopted from CHINA. The proprieties of the production meet the requirements of Chinese standard DB3201Q1887 (details is shown below in table “ Quality Standard of SPB Vertical Drains “ ). Proposed Design Philosophy, Construction, Installation and Monitoring Method As per of Section of ITB 5 5 uality Standard of SPB Vertical Drains Parameter Unit Type Remarks SPB1 SPB2 SPB3 Materials Plastic strip core coated with a membrane filter Section dimensions Width mm 100?2 100?2 100?2 Thickness mm ? ? ? Longitudinal drain capacity m3/s 15*106 25*106 Side pressure 350KN/m2 Tension strength KN/10cm Elongation is 100% Elongation 10 10 Permeability coefficient cm/s 5*104 5*104