Construction unit of soft soil improvement

Description

Construction unit of soft soil improvement
Soils having poor engineering characteristics now demand more consideration in construction activity, especially in regions where good quality ground is in short supply. Surcharge preloading with prefabricated vertical drains (PVDs) is one of the most popular techniques for ground improvement involving soft soils. The inclusion of the PVDs into the ground artificially reduces the drainage path length, thereby speeding up the consolidation process which may otherwise take many years to achieve substantial completion for soft soil deposits. However, the surcharge loading required to ensure such deposits undergo acceptably low amounts of settlement post-construction are often so large that, in maintaining an adequate factor of safety against slope instability, it may prove rather time consuming to apply the necessary fill layers. In this regard, use of the vacuum consolidation technique in conjunction with surcharge preloading and PVDs can enhance the efficiency of ground improvement works. The vacuum preloading technique, originally proposed by Kjellman (***2), has over the past three decades evolved to become a viable, more cost-effective solution for ground improvement projects worldwide. This has been largely due to improvements in geosynthetic/PVD and vacuum pump technology.


Construction unit of soft soil improvement