Engineering and environmental aspects of offshore soil mixing

Abstract

The increasing number of near-shore and offshore projects for commercial, residential or energy-generation purposes has led to the accelerated development of marine construction technologies. Some of these methods have been conceived to improve the geotechnical properties of soft seabed deposits. Cutter soil mixing (CSM) is a recent deep mixing method for the stabilisation of soils. This mixing procedure was initially developed for on-shore projects, but a few near-shore applications have been carried out. The research in this paper is on the possible use of CSM as an environmentally friendly offshore ground improvement technique. A specific full-scale trial was performed simulating offshore conditions. The complete process and the main production parameters were continuously monitored during the installation sequence. A comprehensive monitoring and sampling campaign was conducted at the site, and laboratory analyses were carried out on the collected water samples to investigate the water quality throughout the test. Finally, unconfined compression tests were undertaken to determine the geomechanical performance of the improved soil achieved after 28 curing days. The results suggest how CSM may be regarded as a valid technology for improving the physical properties of seabed soils, limiting the risk of negative environmental impact on the surrounding water.

The effect of curing conditions on the hydromechanical properties of a metakaolin-based soilcrete

“…In DSM applications (e.g. Larsson, 2003;Rutherford et al 2005;Topolnicki, 2012;Bruce et al 2013;Spagnoli et al, 2014;Bellato et al, 2015;Doherty et al, 2016;Bellato et al, 2020) treatment units such as columns or panels of soilcrete are combined to form structural elements (slabs, walls, foundation blocks…). To date the large majority of DSM treatments are formed using Ordinary Portland Cement (OPC) as binder.…”

Model Tests and Numerical Simulations of Grouted Connections in Offshore Wind Turbines Under Low Circumferential Repeated Loads

“…Offshore wind energy is a clean renewable energy source, and the promotion of offshore wind farms in Europe has achieved great economic value [5][6][7][8] . The marine platform and foundation connection part supporting the wind turbine is one of the key parts to ensure the normal operation of the wind farm [9][10][11][12] . At present, many scholars at home and abroad have used numerical simulation to study the stress state near the shear keys of grouted connection sections and formed clear design speci cations to guide the design [13][14][15][16][17] .…”

First Deployment of the Underwater Drill Rig MeBo200 in the North Sea and its Applications for the Geotechnical Exploration

“…For instance 25-30kPa at 45m depth was measured in the Quaternary deltaic clay off Borneo (Gemeinhardt and Wong 1978). Micic et al (2003) and Bellato et al (2015) also state that typical values of such sediments ranging between 5 and 40kPa may cause some problems when offshore platforms have to be founded in these soft marine deposits. Particularly challenging is handling the samples of these sediments, therefore in situ tests are preferred.…”