Abstract Electroosmotic consolidation effect of electrode configuration and fracture grouting with sodium hydroxide were investigated. In this study, a series of laboratory tests were performed by using a homemade electroosmotic cell. Results indicate that electroosmotic consolidation that uses fracture grouting with sodium hydroxide effectively improved the mechanical properties of dredged clay sediment

Abstract Based on the soil behavior type (SBT) and its parameters (I c) obtained by cone penetration tests (CPTs) in the Yellow River Delta, the standardized shear wave velocity (Vs1), permeability coefficient (k), and fine-grained soil content (FC) were calculated. The fine-grained soil content offshore is higher than that near the coast. The shear wave velocity is primarily distributed in the range

Abstract In this paper, the engineering application of microbial self-healing concrete in ship lock engineering was studied. Researches including the design and batch preparation of microbial self-healing agent, and laboratory tests of microbial self-healing concrete were carried out. A class of self-healing agents containing microbial spores and calcium sources was designed and batch-produced by spray

Abstract The coral reef pores are the main reservoir space of oil and gas resources. Through determining the structural form and distribution characteristics of pores, it can be helpful for scientific and reasonable stratigraphic division and reservoir evaluation, and provide basic data for the efficient development of using coral reefs as oil and gas reservoir sites. The core difficulty of interpretation

Abstract Hydrate reservoirs present numerous challenges due to their occurrence in ultra-deep regions, presence of mud-layers, unconfined boundaries, and complex morphological heterogeneities. Individual effect of some of these reservoir settings on overall production is known, however, a systematic assessment of their mutual impact on gas production and land subsidence is essential from production

Abstract The effect of the initial deviatoric stress direction and magnitude of deviatoric stress q on the strain components and non-coaxial behavior of soft marine clay during principal stress rotation was experimentally examined. The strain components and pore water pressure depended considerably on the deviatoric stress direction and q. Through polar diagrams, a notable non-coaxiality was observed

Abstract This study presents finite element analysis (FEA) results of suction buckets subjected to vertical sustained uplift loads, focusing on the suction pressure and the displacement responses. The accumulative seepage of water and the heave of the soil in the bucket are the key components of the displacement. The accumulative seepage of water is modelled using a layer of soft elastic material (water

Abstract The large-diameter monopile, as one of the most used foundations of offshore wind turbines, is subjected to severe sea conditions, such as the cyclic lateral loads induced by wind and waves, as well as the scour induced by the flushing currents. The combined cyclic lateral loads and scour introduces additional complexity and is encountered in offshore wind turbines as well as other offshore

Abstract Chennai is a major metropolitan city along the southeast coast of India and is popular for its world’s second longest sandy beach called as Marina beach the shoreline of which has been gradually advancing towards the Bay of Bengal over a century. The advance of the shoreline is due to the construction of breakwaters for the formation of the harbor of Chennai port, one of the 12 major ports

Abstract Stick of the deep-sea sediment on the surface of the mining machine can deteriorate its working efficiency. To resolve this issue, this study aims to reduce the adhesion force along the soil-metal interface by adjusting the roughness of the metal surface. During the experimental study, six types of Titanium samples with different surface roughness were first prepared through surface polishing

Abstract During remote monitoring of the Persian Gulf to detect oil spills, conducted from 2017 to 2019, leaking oil on the sea surface was observed at an offshore site. The site was located 26 km west of the Sir Abu Nuyar Island in the waters of the United Arab Emirates. A more detailed analysis was conducted using remote sensing data, particularly synthetic aperture radar and optical images from

Abstract Offshore wind turbines (OWT) subjected to long-term complex marine loads are prone to foundation damages, affecting their regular operation. However, the failure mode of the large-diameter monopile foundation under complex marine loads is not well understood. Hence, failure modes of monopile foundation for OWT in soft-soil seabed under unidirectional and multidirectional loads are investigated

Abstract Recently, many of the world’s major river deltas have been sinking, making them increasingly vulnerable to floods and storm surges, salinization and permanent inundation. For the Yellow River delta, annual subsidence rates of several to dozens of centimeters have been reported in the past few years. The extraction of a considerable amount of groundwater due to continuous pumping is suggested

Abstract The dynamic cone penetration test (DCPT) is a common method for assessing the physical and mechanical properties of cohesionless soils. However, current formulas might not be suitable for carbonate granular soil because of its unique engineering properties. In this study, a series of DCPTs were conducted on carbonate granular soil in the field and laboratory using a light dynamic penetrometer

Abstract Embankment is vulnerable to scouring and erosion during heavy rainfall events in most coastal areas in China. In this study, microbially induced calcium carbonate precipitation (MICP) technique was applied for sand embankments for scouring/erosion control. Three small-scale MICP treated sand embankments and one untreated embankment were first prepared using the injection method. Then, a series

Abstract The mechanical properties of calcareous sands are very different from those of terrestrial sands as the particle crushing occurs under low confining pressure. If the calcareous sand is used as the foundation materials, engineering problems such as the uneven settlement of the foundation are prone to occur. In this paper, the Polyurethane foam adhesive (PFA) is used to improve the calcareous

Abstract Pile foundations are one of the significant marine substructure systems for a variety of offshore and onshore facilities. Thus, optimum and reliable design during their lifetime and under inherent uncertainties is noteworthy. Among various methods for predicting axial pile bearing capacity, cone penetration test (CPT)-based methods enhance geotechnical design to a more satisfying level due

Abstract Taut or semi-taut mooring lines are often used in deep-sea area to connect the floating structures to the anchors in the seabed. In previous studies, the quasi-static analysis method was adopted to assess the load transfer of the mooring line. However, the inertia effect of mooring line and chain–seabed dynamic interaction cannot be neglected in practice. In this paper, the soil strain rate

Abstract This study investigates the effect of combined operational and seismic loads on the dynamic fore-aft, and the side-side response of monopile supported OWT in liquefiable soil under operational and parked conditions. A two dimensional (2 D) coupled soil-pile-structure interaction model is formulated in OpenSees, where the monopile and tower are modeled as Euler-Bernoulli beam elements, the

Abstract This paper performs finite element (FE) analysis to investigate the behaviour of a large geotextile mat offshore dike on clay-overlaying-sand soil deposits, which is reinforced by a new type of non-uniform thick geotextiles technique. A FE model is generated and validated against laboratory centrifuge testing data. A comprehensive parametric study is then conducted to examine the influences

Abstract An experimental investigation was conducted to understand the impact of salinity on the microstructure, phase composition, and shear strength of cement-treated Champlain Sea clay. Based on a scanning electronic microscopy (SEM) analysis, Champlain Sea clay exhibits an open structure fabric with flocculated particles. Leaching results in de-flocculation of the aggregates and leads to an increase

Abstract In this paper, the governing equation of chloride diffusion in reinforced concrete square piles is presented. The deterioration process of a pile caused by chloride-induced reinforcement corrosion is analyzed. The time-varying degradation coefficient of the flexural rigidity of piles induced by reinforcement corrosion is obtained. The time-varying failure probability and reliability index

Abstract Vacuum preloading combined with electroosmosis (VE) has a good drainage effect, but electric vertical drains (EVDs) as the drainage plate and electrode will cause the offset of water flow near the anode. Therefore, there is an alternate time for the optimal use of the two methods. In this paper, some macroscopic indexes were monitored through laboratory tests to explore the optimal alternate

Abstract Based on a self-designed preloading consolidation model test system with vertical drains, saturated marine soft clay drainage consolidation and thermal drainage consolidation model tests were carried out at room temperature and high temperature, respectively. The variations in the soil temperature, excessive pore water pressure and surface subsidence over time were recorded in the tests. The

Abstract The soil around the pile foundations of offshore wind turbines (OWTs) would suffer from earthquakes which are widely believed to undermine the bearing capacity and serviceability of foundations. The non-intermittent lateral environmental loads in the ocean (e.g., wave, wind, and current) continuously act on OWTs. However, the seismic response of pile foundations and the soil around is less

Abstract Submarine telecommunication cables, which carry about 99% of international telecommunications, are usually buried shallowly beneath seabed and vulnerable to seabed movements. In recent years, many submarine cable damages have been observed when significant lateral seabed movements occur due to geohazards, e.g., offsets of strike-slip faults and submarine landslides. However, research on the

Abstract Sub-bottom profiling traditionally uses low-frequency signals (less than 20 kHz) to examine layered structures of the bottom sediment in large depth, but it has some limitations in deep-sea surveying. The surficial sediment within several meters under the water–sediment boundary in the deep sea cannot be distinguished clearly. In this study, a high-frequency sub-bottom profiler (HFSBP) was

Abstract This research aims to study the effect of pile arrangement and inclination on the bending moment of piles as well as the horizontal acceleration of the cap under explosion loadings. Data was obtained from five centrifuge tests, which were performed on a 2 × 2 pile group with various arrangements of vertical and batter piles. The results showed that among all the tested models, the pile group

Abstract In seafloor mining environments, ultrasonic detection is often used for underwater target recognition, and a large number of suspended particles reduce the recognition rate of single-classifier cobalt-rich crusts. In this paper, we propose a recognition method based on multi-classifier fusion (MCF). First, the kernel Fisher discriminant analysis (KFDA) method is used to reduce the multi-class

Abstract A closure on the recent discussion regarding the review on the behavior of helical piles as a potential offshore foundation system by the Authors is presented. Installation torque, uplift capacity, installation effects, model pile, installation speed and results proposed by Discussers are commented.

Abstract Monopiles are popular solutions as the foundation to support offshore wind turbines (OWTs), which suffer from various amplitudes of continuous lateral cyclic wind and wave loading. The accumulation of tilt and change of the natural frequency of OWTs under cyclic loading have become crucial issues for OWT design. Hence the monopile-tower-soil system was established at the small-scale level

Abstract Geosynthetic-encased stone column (GESC) has been proved as an effective alternative to reinforcing soft marine clay soils with low undrained shear strength. In this paper, three-dimensional (3-D) coupled mechanical and hydraulic modeling based on centrifugal model test was carried out to investigate the performance of GESC-supported embankment over soft clay with two different stiffness of

Abstract Marine sandy soils may liquefy under wave loading and/or seismic loading. Current research shows that the presence of fines can significantly affect the liquefaction potential of sandy soils. Thus, a quantitative evaluation of the effect of fines on the undrained behavior of sandy soils can provide useful information on soil liquefaction that can advance the design of foundations of coastal

Abstract Soil liquefaction can be induced by natural events that entail complicated loading directions and magnitudes. To investigate the liquefaction behaviour of granular material under complex loading conditions, a series of strain-controlled cyclic simple shear tests are conducted on the uniform-sized glass beads. These tests include uni-directional and multi-directional loading paths. An energy-based

The degradation of rock mechanical behavior after cyclic wetting and drying could affect the stability of rock slope, embankment, and tunnel significantly. A series of tests were first conducted on sandstone collected from a reservoir bank slope. The results showed that the mechanical parameters (including tensile strength, uniaxial compressive strength, elastic modulus, and internal friction angle)

Aiming at the problems of soil column forming near the plastic vertical drains and soil cracking during electro-osmosis stage in the treatment of dredged slurry by vacuum pre-loading combined with electro-osmosis method, this paper proposed a new method, i.e. vacuum pre-loading combined with electro-osmosis and with dynamic compaction method. Through the laboratory model tests in self-made glass bucket

Under seismic loading, marine soil experiences horizontal shearing in two directions with different shear directions and amplitudes. It is therefore of considerable practical relevance to study the deformation behavior of marine cement soil under bidirectional shear loading. In this study, a series of cyclic simple shear tests were carried out to investigate the undrained deformation behavior of marine

Stabilization/solidification (S/S) has been examined as an effective way to strengthen soft soils. However, the presence of organic matter (OM) in dredged marine silt can substantially weaken the reinforcement effect of S/S. To treat organic silt that is difficult to strengthen by S/S, a new combined application of S/S and electroosmosis (EO) treatments was adopted in this paper to increase the strength

This study investigated effects of initial deviatoric stress state and the orientation of their major principal stresses on the strain components and shear strength of soft marine clay. Hollow cylinder test results demonstrated that the axial and circumferential strain component magnitudes substantially depended on the initial deviatoric stress and the principal stress direction. The octahedral shear

This paper presents a case study on the improvement of thick marine deposits. A new method that combines vacuum pressure and surcharge load with no need for a sand cushion is proposed and evaluated. The main features of this method are as follows: (1) each integrated prefabricated vertical drain (PVD) is connected directly to a branch pipe, which is in turn connected to a main pipe with a T-shaped

Knowledge of the processes governing salt intrusion in estuaries is important since it influences the eco-environment of estuaries as well as its water resource potential in many ways. The aim of this paper is to test the effectiveness of the new 1-D thermodynamic salt intrusion equation proposed by Zhang and Savenije (i.e., is an extreme power theory for the mixing of saline sea water and fresh river

Impulse waves generated by landslides lead to serious secondary disasters. To investigate the effects of impulse waves on a bank slope, a three-dimensional physical model test was conducted considering multiple factors, such as the width, thickness, and volume of the landslide body, inclination angle of the landslide, and bank slope angle. The results show that the wave did not break upon the first

In NGI-type simple shear apparatus, including recently developed NGI-type bi-directional simple shear apparatus, the complete stress state is unknown which limited the interpretation of test results. This study compares the stress state of NGI-type simple shear test obtained by two methods, the stress state determined by an empirical method using test data, and stress state determined by measured values

Investigation of gas migration in saturated soil is of great theoretical and practical significance in marine science and engineering. The transport of gas bubbles in soil and its effects on soil physical and mechanical properties can be further studied. Gas injection and permeability tests were conducted using a self-developed oedometer with gas injection and water infiltration. Before the gas injection

A closure on the recent discussion regarding the review on the behavior of helical piles as a potential offshore foundation system by the Authors is presented. Installation torque, uplift capacity, installation effects, model pile, installation speed and results proposed by Discussers are commented.

The use of complex piers to build bridges has become widespread. In this study the experimental data was obtained to determine scour hole's dimension and its changes versus pile cap elevation. Five models with different geometry were used in experiments under clear water condition and thresholds velocity. The models were made with an appropriate scale from real piers of bridges. A 3D illustration of

Model tests accompanying numerical analyses on the modified suction caissons (MSCs) in saturated marine sand subjected to inclined loading were conducted to investigate the bearing behavior and earth pressure distribution along the embedded depth. Influences of external structure sizes, inclined loading angles and loading point position on the inclined bearing behavior were discussed. Results show

Cement treatment is a promising and effective method to enhance strength of calcareous sand in regions where offshore foundations and coastal facilities are localized. In treatment, the added cement content and curing period influence the strength of cemented calcareous sand. In order to regulate the loading resistance of cemented calcareous sand, effects of cement content and curing period on strength

Monopiles are widely used to support the upper structures of wind turbines in offshore engineering. Due to harsh environmental conditions, they are subjected to long-term lateral cyclic loading from waves and winds during the design life. A robust beam on the Winkler foundation model is presented to analyze the responses of monopile foundation under long-term lateral cyclic load, incorporating cyclic

Submarine pipelines are likely to be impacted by frequently catastrophic landslides, resulting in broken pipelines and causing irreversible economic losses; however, because pipelines located in deep-sea environments are simply laid atop the seabed, effective protective measures have not yet been proposed. In this paper, a pipeline with a uniform distribution of honeycomb holes on the surface, namely

This paper studies a novel CTD sensor (SZQ1-1) which is developed for underwater glider to meet the requirement of autonomous acquisition of high-quality profile hydrodynamic oceanography data. An independently developed electromagnetic induction type conductivity sensor, a quick response thermistor and a high-precision pressure sensor is used to integrate the CTD sensor. Several designs of compact

The hydrodynamic characteristics (wave transmission, reflection, and dissipation) of nine different scrap-tire floating breakwater configurations are studied in a wave flume for a wide range of input wave conditions. The breakwater has 3 different configurations: a) four and b) eight rows of tires as well as c) four rows in two levels. The effect of these configurations is assessed on the hydrodynamic

Cement stabilized clay (CSC) from dredged sediment or sludge is receiving increasing attention for its use as construction material. In this paper, seven CSC mixture samples were tested to investigate the effect of constituent proportion parameters and curing time (T) on strength characteristics. Results illustrate that clay-water/cement ratio (W/C) is significantly related to the unconfined compression

Abstract Helical piles have emerged as an attractive foundation system for offshore applications with renewed interest from the offshore community. Significant research gap currently exists in transferring this technology offshore and this paper discusses how existing and emerging knowledge can be successfully used to bridge some of the gaps. We focus on the Coupled Eulerian Lagrangian (CEL) large

The organic matter within clay soil is one of the important factors affecting its engineering characteristics. In this study, the influence of organic matter on the strength evolution of cement-stabilized marine soft clay is evaluated by scanning electron microscopy (SEM) and unconfined compressive strength (UCS) testing. The experimental results show that the after-curing clay water content of the

Flow liquefaction is a catastrophic failure phenomenon of loose sand when subjected to wave or seismic load, and an instability state can be regarded as the onset of flow liquefaction. Most of the previous studies focused mainly on the static instability state, while the investigations on cyclic instability state (CIS) are very limited and unsystematic. The characteristics of CIS are complex and there

The accurate knowledge of the location and movement of the sand bars is important for the coastal manager to establish correctly the coastal defence elements. This work applies a numerical model of finite elements based on Galerkin's formulation for predicting the location of the start, crest and end of the outer bar. The model that shows the best results is the one that combines the variables wave

Fragile angular-shaped granular materials, such as calcareous sand, rockfill material, and ballast, show complex stress–strain–volumetric relationships due to the effects of particle breakage. This paper presents a proposed constitutive model to simulate the effects of particle breakage on the mechanical response of calcareous sand and rockfill materials in drained triaxial tests previously conducted

The dredged clay (DC) could not be directly reutilized for its extra-high water content. So, the dewatering is needed before further improvement. At present, the commonly used self-weight sedimentation and natural air-drying are often difficult to meet the engineering requirements and time-consuming, thus chemical flocculants are used to improve the dewatering process for their excellent flocculation

The Orange Basin situated offshore South Africa has been subject to various studies as it is gas prone, but limited literature exists on the determination of fluid contacts. The availability of well logs, repeat formation tests (RFT), and drill stem test (DST) results make the Orange Basin an ideal example to carry out studies on the integration of these data to understand the fluid contacts in the