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

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 deformation

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

In recent years, bucket foundations have continuously been developed for offshore wind turbine, and the diameter of the bucket foundation has also increased with an increase in the load subjected to wind and waves. However, the bucket foundation can experience minor inclination during the installation process owing to soil anisotropy, which can largely increase the installation resistance. First, two

The use of vacuum preloading combined with electro-osmosis (VP-EO) to treat dredger fill from seabed has been studied extensively. However, there remain some drawbacks to this method, such as clogging outside of the prefabricated vertical drains (PVDs) and the inhomogeneous consolidation of soil. A novel method for stepped vacuum preloading combined with stepped voltage electro-osmosis (SVP-SVEO) was

This study proposes a methodology to prevent excessive and misuse of polymers in dewatering applications. In this study, to determine the optimum conditions some measurement were performed such as zeta potential measurements to arrange the pH of the slurry, flocculation tests to reduce turbidity and settlement time, particle size distribution analysis to enhance floc size, and Fourier-Transform Infrared

Offshore engineering is facing the challenges of modeling large deformation problems combined with the complexity of spatial variability of soils. This complex large deformation problem has not been extensively investigated, where one reason is believed due to limited practical approaches available. In this paper, the complex problem has been addressed through the in-house developed approach by implementing

Accreting soil system with horizontal drainage layers (HDLs) widely exists in engineering practices. With the existence of HDLs, each soil layer undergoes two stages: layer formation stage and surcharge loading stage. The methods proposed by Gibson and Zheng et al. are adopted to derive the analytical solution for the layer formation stage, while the separation of variables method and Duhamel’s principle

This study examines the effect of the initial fabric on the coefficient of the lateral earth pressure at rest K0, the undrained monotonic loading strength and the liquefaction resistance of a calcareous sand from a reclamation land in Persian Gulf. K0 consolidation, undrained compression and extension and cyclic undrained loading triaxial tests are performed on laboratory samples reconstituted by air

An innovative plate anchor, increasing its bearing section area during uplift is introduced in this paper. In this experimental study, the influence of the embedment ratio (depth of embedment/anchor width) of the plate anchor and anchor width (120, 150, 180, 250 mm) on the anchor pullout capacity and anchor displacement during an uplift test is investigated. Particle Image Velocimetry (PIV) is used

This paper proposes a coupled fluid half-space - strip foundation - poroelastic half-space vibration model to study how dynamic water pressure caused by strip vibration affects foundations operating offshore. Both vertical and rocking vibrations are considered. The governing equations of the problem are obtained using the Biot’s theory and proper boundary conditions at the seawater - seabed interface

A 2 D cross-shore transect model with variable density and saturation was established in FEFLOW to investigate the groundwater dynamics and solute transport under the influences of three tidal conditions. This study resulted in four major conclusions. The phreatic aquifer acted as a low-pass filter accompanied by a longer period in groundwater fluctuations. More obvious stability was observed in the

Piled raft is the most desirable foundation option in the recent era for offshore and onshore structures which are often exposed to combined vertical and lateral (V-L) loads. Due to the scarcity of literature, this study aims to comprehend the response of the piled raft foundation (PRF) under combined vertical and lateral loads. A series of laboratory experiments and finite element analysis has been

The present research investigates the undrained behavior of calcareous sand of Qeshm island in the south of Iran. The study was performed through undrained cyclic and monotonic stain-controlled triaxial tests on two relative densities (40 and 70%) and different effective confining pressures. Five different amplitudes of strains including 0.01, 0.07, 0.14, 0.7, and 1% were applied for cyclic triaxial

Submarine groundwater discharge is the main way to transfer land-based sources to the ocean. To verify the in situ monitoring capability of the multichannel electrical resistivity method for groundwater discharge in the coastal zone during tidal processes, in situ monitoring was carried out in different aquifers of Shilaoren Bay in September 2015 and May 2017. The electrodes were placed on the seabed

A series of oedometer tests were conducted on slurries with three additives (NaCl, CaCl2, and FeCl3) of different concentrations in pore water (0.1–1.0 mol/L) to investigate the effect of the valency of cations and their concentration on the consolidation–compression behavior of slurries. Further laboratory model tests on the vacuum consolidation of a prefabricated vertical drain (PVD) unit cell were

Millions of cubic meter of sediments are dredged annually to open channels for navigation of ships in ports and harbors. Beneficial reuse of these dredgings is typically possible upon their stabilization with calcium-rich amendments. A series of long-term laboratory column leaching tests and contaminant transport models were employed to study metal leaching behavior of bottom-sea dredged material (DM)

Engineering vessels play an important role in offshore engineering operations, and the control of their motion under the effects of sea environments is crucial for the safety and efficiency of the operation. In this study, a real-time monitoring system for vessel motion and sea environment with synchronization function designed at the Harbin Engineering University is introduced. The system consists

Based on limit equilibrium analysis, this paper presents a general pseudo-dynamic solution for the seismic active earth pressure considering anisotropic seepage conditions. The proposed method is applied to a vertical waterfront wall retaining fully submerged backfill with a drainage system along the soil-structure interface. To simplify the calculation, a steady state hydraulic head field satisfying

Aiming at the problem of serious soil cracking during electro-osmosis stage in the treatment of dredged slurry by vacuum pre-loading in combination with electro-osmosis method, this study proposes a new vacuum pre-loading method in combination with electro-osmosis and with dynamic compaction to overcome these drawbacks. Meanwhile, different current ratios are used to characterise the different activation

Based on an analysis of current research regarding dune migration and deformation monitoring methods, high-precision ground-based synthetic aperture radar (GB-InSAR) interferometry was used for continuous dynamic monitoring of the migration and deformation of dunes in Changli Gold Coast in Hebei Province, China, a typical area of coastal dunes. Methods for interpretation and key data processing were

Submarine pipeline was widely used to transport oil and gas in offshore petroleum exploitation. In practice, deep-water pipeline experiences several times of maintenance every year. This periodic open-up and shut-down operation causes cyclic rise and fall in the temperature of a pipeline, resulting in the periodic expansion and contraction of the pipeline. Due to the characteristics of heating-up operation

Sludge contains a little organic matter. Due to the action of microorganisms, organic matter was decomposed, and released humic acid. It can also affect lime or cement solidified sludge. Three categories of pH solution (pH = 4.0, 7.0, and 9.0) were prepared to soaking sludge. The organic matter and pH were observed for 78 days. The results showed that both acidic and alkaline buffer solutions can accelerate

This paper presents an experimental investigation of the impact of leaching on the geotechnical properties of Champlain Sea clay. Champlain Sea clay has a high salinity level in its pore fluid. A leaching apparatus was developed to leach a series of 15-cm diameter undisturbed Champlain Sea clay samples to different salinity levels. A series of geotechnical tests were conducted on leached samples. The

The mechanical characteristics of calcareous silt interlayers play an important role in the stability of island-reef foundations. Direct shear and consolidation tests were performed to study the relationship between the mechanical properties and the physical parameters of calcareous silt. Based on the consolidation test results and analysis of the settling examples, different calculation methods for

Several hundred million cubic meters of sediment are dredged from various U.S. ports, harbors, and waterways annually to maintain and improve the nation’s navigation system for commercial, national defense, and recreational purposes. The United States Environmental Protection Agency mandated containment of dredged sediments in designated containment facilities. The current study aims to explore the

Pile foundations in calcareous sand are often applied to bear vertical cyclic loads. Model tests of a single pile bearing vertical cyclic loads were performed in calcareous sand, and the accumulated settlement and bearing capacity were measured via sensors using a self-designed experimental device. The influences of the dynamic load and number of cycles on the accumulated settlement and bearing capacity

Rock drilling is a significant activity widely used in the exploration of marine mineral resources and offshore civil engineering such as marine mining, petroleum and deep-water drilling. The characteristics of size and shape of particles produced during rock drilling influence drilling efficiency and energy consumption. We report a series of drilling experiments on sandstone, limestone and shale to

This study investigated the feasibility of using lime (L) and carbide slag (CS) to activate ground granulated blast-furnace slag (GGBS), as a potential substitute to Portland cement (PC) for stabilizing dredged sludge (DS). A series of unconfined compressive strength (UCS), scanning electron microscopy (SEM) and X-ray diffraction (XRD) tests were performed to evaluate the strength development and micro-mechanisms

Settlement behavior plays an important role for the stability of underwater tunnel due to the different responses of fractured surrounding rock to external load. In contrast to the traditional analysis method based on continuum mechanics, the presented numerical model using improved hybrid finite element was performed to study the settlement behaviors of structure, and structural health monitoring

The scour observed at the landside ground behind coastal protection facilities, such as seawalls and coastal dikes, due to tsunami overflows is the main reason for failures in such constructions. In this study, we focused on sheet-like (two-dimensional) scour countermeasures, which do not require large-scale excavation of the ground, and experimentally verified the effects of geonet and mesh sheets

Offshore pipelines need to be trenched and backfilled in shallow waters for physical protection against the environmental, operational, and accidental loads. These buried pipelines may encounter lateral pipe-soil interaction in various incidents such as ground movements, landslides, ice gouging, and dragging by embedment anchors and fishing gears. Using the pre-dredged material for backfilling is a

The reuse of scrap and by-product materials in civil engineering applications has increased in recent years due to environmental considerations. Soil-tire mixtures can be used in land reclamation in marine areas. The effects of tire crumbs on the compressibility behavior of a calcareous soil are evaluated in this study. Calcareous soils are generally located in tropical and semi-tropical areas near

This paper comparatively investigates the capability of 10 solo and hybrid Data Driven Models (DDMs) in predicting the pier scour depth. These models include Support Vector Machine (SVM), Adaptive Neuro Fuzzy Inference System (ANFIS), Artificial Neural Network (ANN), Gene-Expression Programming (GEP), improved Group Method of Data Handling (GMDH1 and GMDH2) and two hybrid forms of GMDH in combination

Scour around piles is considered as one of the most important phenomena which could undermine the stability of piles. Data-driven methods are now being used more and more to predict complex phenomena such as scour around of pile groups. In this study, three data-driven methods including multivariate adaptive regression spline (MARS), classification and regression tree (CART) and artificial neural network

This study analyzes a new wharf structure using a method to calculate earth pressure on a covered type sheet-pile wharf. The earth pressure on the riverside of the sheet pile and the landside of the concrete compresol pile is calculated using the earth pressure theories of Coulomb and Rankine. The earth pressure of the landside of the sheet pile and riverside of the concrete compresol pile is deduced

Physicochemical conditions are proper to form gas hydrate and free gas in the Caspian Sea which are considered both for geohazard assessment and future possible source of energy. Gas migration, hydrate formation and decomposition cause different types of features to form in the seabed and sediments which can be affected by geological and physical conditions of sea. In this study, high-resolution marine

Helical piles are used mainly to resist tension forces generated by uplift and overturning moments of various structures, therefore they have been suggested as a potential alternative to driven piles as offshore pile because they provide a large uplift capacity due to the anchor effect of the helix. To date no standards are available for the assessment of the use of helical piles in the offshore environment

The mechanical behaviour of sedimentary marine soils containing diatoms does not follow classical trends usually found in Soil Mechanics, and evidence of geotechnical singularities of undisturbed samples are still scarce. This article presents new insights on the behaviour of natural diatomaceous soil in compression, shearing and cyclic loading, on undisturbed highly plastic diatomaceous silt from

In the present scenario, with much focus on sustainable development worldwide, Microbially Induced Calcite Precipitation (MICP) is a promising biological soil improvement technology. However, only very limited research is reported on the effectiveness of this technique in marine clays. This paper presents the salient features of an experimental study conducted on two typical marine clays stabilised

This is the first attempt to study the effect of debris on the scour at side by side pier and abutment. A large set of experimental tests was carried out at the hydraulic laboratory of Shahid Bahonar University of Kerman, in a tilting flume with 10 m length, 0.8 m width and 0.5 m depth. Effect of debris shape, thickness, position, length, and the distance between abutment and pier was investigated

The current study investigated the effect of the initial static shear stress orientation on the liquefaction behavior of Hormuz Island calcareous sand. An experimental study was performed using nine monotonic and 43 cyclic undrained bidirectional simple shear tests. The experiments were conducted on loose and dense samples having different cyclic shear ratios and initial static shear ratios (α) at

Single particle crushing tests were conducted to investigate the size effect on the crushing behaviors of single calcareous sand particles experimentally and numerically. The particle crushing strengths and fragmentation modes of the calcareous sand particles with six different size groups (5–17 mm) were investigated. Moreover, the numerical simulation based on discrete element method was performed

Grain size, sorting, skewness, and kurtosis studies are of great importance in order to texturally characterize the sedimentary environments. These parameters are useful in order to characterize the dynamic beach environment, which is of potential interest for research on natural resources and to interpret analogous ancient sedimentary environments. The purpose of this paper is to investigate the characteristics

The jacked-in pile method provides a substitute procedure that permits the installation of pre-formed piles with negligible vibration in a noiseless manner, thereby reducing noise impacts in marine and urban environments. This research was carried out by using a small-scale physical modelling approach to examine the movement of soil during pile installation. The model soil was formulated from a mix

This article presents the results of a marine geophysical and sedimentological study carried out around Lesvos Island (NE Aegean) to investigate the potential of exploitable marine aggregate (MA) deposits that could be used for beach replenishment purposes. Sub-bottom profiler data showed a good prospect for potential coarse-grained deposits in two of the three surveyed areas around Lesvos. Grain size

A simplified method for predicting the nonlinear dynamic response of composite caisson-piles foundation (CCPF) under scour conditions is proposed. The Hardin-Drnevich model is employed to represent the nonlinear soil reactions. Stress history is also considered to study the scour effect on the dynamic impedance of foundation. Then, harmonic vibration tests considering scour are conducted on a CCPF

Nowadays offshore wind turbines have been widely used for wind energy exploitation. The lateral bearing capacity of monopile is important to ensuring the safe operation of monopile based offshore wind turbines. As one of the most used forms of foundations for offshore wind turbines, the monopile is subjected to vertical loads induced by its own weight and superstructures, and lateral loads engendered

A monopile is the most widely used foundation type for offshore wind turbines. Long-term cyclic loading from wind and waves creates an accumulated displacement and changes in the stiffness, which are critical in the serviceability limit state. Design codes present little information in this regard. A series of model tests were conducted to further explore cyclic response of a stiff pile in drained

In this paper, a study on whether the use of polymer would affect the engineering properties of marine clay during and after the consolidation stage was carried out. A polymer, polyacrylamide (PAM) was used in this study. Unconfined compressive tests and permeability tests on PAM-treated soil were conducted. The testing results were compared with the results of untreated marine clay. The test results