Investigating the effectiveness of deep cement mixing in deep sea: A static load testing case study

Abstract

This research demonstrated a marine reclamation project in Hong Kong's deep-sea region, which employed the economically efficient and environmentally sustainable deep cement mixing (DCM) clusters for the reconstitution of marine sediments. This study offers a detailed introduction to the installation of DCM clusters and the conduction of subsequent static loading tests, providing experiences for forthcoming endeavors in marine reclamation, particularly in regions akin to Hong Kong. To ensure that both compressions and lateral movements do not exceed the acceptance criteria, the finite element method (FEM) was employed to navigate the construction of DCM clusters effectively. Subsequently, static load tests were conducted, with meticulous measurement of compressions and lateral movements. The results show that the maximum vertical compression and lateral movements are approximately 4 mm and 10.8 mm, respectively, which are significantly beneath the corresponding acceptance criteria (i.e., 40 mm and 60 mm for vertical and lateral movements). A comparison between field measurement outcomes and simulation results supported the capability of FEM in identifying the crucial movement characteristics of DCM clusters, albeit a discernible discrepancy, predominantly being attributed to the conservative parameters utilized in the FEM model as per existing specifications. This delineation underscores the imperative need for the development of region-specific guidelines.