This study describes the soft ground improvement treated with various vertical drains at a full-scale trial field test site at Yangsan area in Korea. A field test site was constructed to evaluate the performance of vertical drains for soft ground improvement. The test site was heavily instrumented, and good performance data were obtained. Various vertical drains such as paper drains, pack drains and menard drains were installed with different type and spacing at this test site. The key objectives of the test site were the development of specific information regarding the consolidation characteristics of the marine soft clay layer, the behaviour of the clay near limiting equilibrium, and the strength increasing of the foundation layer under embankment. Works are being conducted for three years from 1996 to the present time. This field test site is located Yangsan area near Pusan in Korea. This paper described the performance of the vertical drains in this test site. It presents an analysis of the deformation and pore pressure data recorded, with conclusions regarding the practical effectiveness of the vertical drains installed. The vertical settlements, lateral deformations, and strength parameters were evaluated using the field test data from instrumentation of settlement plates, extensometers and inclinometers, and predicted using finite element method and observational prediction method. In this paper, relationships for vertical settlement and lateral displacement during and after embankment construction, strength changes of foundation clay between before and after drain installation, and etc. were obtained. These relationships can be used effectively for prediction of the rates and magnitudes of the behaviour of the foundation clay treated by vertical drains under embankment on marine soft soil.
This study is concerned with the soft ground improvement by paper pack and menard drains at full-scale trial field test site at Yangsan area in Korea, The location of trial field test site is shown in Figure 1. A comprehensive array of 3 embankment was built in the same field test site with 3 different ground improvement techniques to assess the relative efficiency of various vertical drain schemes.
