Marine Soil Research Articles

Geotechnical Properties of Soft Marine Soil at Chan May Port, Vietnam

Soft marine soil deposit is distributed under the sea with many special properties. This type ofsoil is rarely researched in Vietnam because of the difficult geotechnical investigation under the sea level.In this paper, the experimental laboratories were performed to investigate the geotechnical properties ofsoft marine soil at Chan May port, Vietnam. The field investigation results indicate that the thickness ofsoft soil varies from a few meters to more than ten meters. Soft soil has a high value of water content,void ratio, and compressibility and a low value of shear strength. The compression index has a goodrelationship with water content, liquid limit, and dry unit weight. The unit weight, shear strength, and preconsolidationpressure increase with the increase of depth. These results show that the soil in the studyarea is unfavorable for construction activities.

Impact of Colonialism on Environment: A Socio-Ecological Study of Twilight in Delhi

Massive devastation of indigenous social ecology was envisaged during the colonial expansion in almost all parts of the world since the 16th century. This colonial craze resulted in the exploitation of the natural resources of the colonial territories, which leads to environmental degradation. The alarming consequences of economic expansion including depletion of the ozone layer, air pollution, loss of forests and biodiversity, extinction of animal and plant species, loss of marine life, water and soil pollution have occurred at an alarming rate. Substantial destruction has greatly affected the global environment in the shape of global warming, urbanization, and massive industrialization among other grave issues. Modern intelligentsia and academia give rise to environmental consciousness through multiple campaigns including the celebration of “Earth Day”, the emergence of environmental activist organizations like “Friends of the Earth”, “Earth First”, “Sea Shepherd” and the formation of “Association for the Study of Literature and Environment ASLE” in America, the vis-à-vis start of Environmental studies and Ecocriticism at universities all over the world. Soon it prospered into further interdisciplinary and multidisciplinary fields of studies, in addition to the environmental campaigns activated across the world.

Evaluating Biosedimentation for Strength Improvement in Acidic Soil

Marine clay soils are problematic soils in the construction industry when they are subjected to construction loads. When these soils are loaded, they lose their structure. This leads to the soil being unable to withstand loads of any magnitude without exhibiting significant, permanent deformations. In order to stabilize the marine soil, new methods for soil improvement were built upon biogrouting by incorporating physical, biological and chemical treatments into the soil. However, the biggest challenge of this method is the bacteria migration through the soil medium. To overcome this issue, the electrokinetic phenomenon can be utilized alongside biogrouting to prevent the bacteria migration. In this regard, the present study applied electrobiogrouting stabilization to investigate the improvement of acidic marine clay soil with a pH of 3.69. To accomplish this, two large-scale physical models with dimensions of 500 × 300 × 1200 mm were fabricated to examine the influence of two different treated distances between the inlet and outlet—450 mm (D45) and 600 mm (D60)—on the stability of the treated soil. It was observed that the shear strength of the treated soil improved significantly. The shear strength at the D45 treated distance increased from 3.65 kPa (untreated soil) to 28.14 kPa (treated soil). However, the strength increased by increasing the treated distance. In addition, compressibility and soil electrical conductivity were reduced significantly, and the Atterberg limits were significantly enhanced from OH to OL. The reasons for the enhancement of treated soil were the formation of CaCO3, which filled the soil voids, and that the water content was reduced. To address issues with marine clay soil, this study aims to minimize the high cost of a special foundation system and the use of non-environmentally friendly materials such as calcium-based binders, aside from the reduction of deformations caused by loading. The findings of this study can be used for acidic soils and the improvement of soil’s geotechnical behavior in general.

Bearing performance of steel pipe pile in multilayered marine soil using fiber optic technique: A case study

It is important to appraise the performance of the steel pipe pile performance in harbor engineering. The load transfer mechanism and pile-soil interaction could not be clearly understood using the traditional measurement. In this case, fiber Bragg grating (FBG) and Brillouin optical time domain reflectometry (BOTDR) were applied simultaneously at an open-ended steel pipe pile field test in Ganyu Port, China. Results showed that the fiber optic sensing system accurately measured the axial force, side friction, and bearing behaviors of open-ended steel pipe piles based on strain data. During the pile driving stage, the system captured the bending deformation and eccentric load on the upper part of the pile above the mud surface, identifying the relatively large tensile strain at the final stage of driving. For the static load test, the strain and resistance distribution obtained by sensing systems suggested that 80% of pile compression was concentrated in the upper 20 m, and the maximum force was observed at the location of soil surface. The precision of high strain dynamic tests is limited for complex field conditions and model’s parameters-setting.

A new methodology to assess the potential of conjectural trigger mechanisms of submarine landslides exemplified by marine gas occurrence on the Balearic Promontory

The destructive potential of submarine landslides for populated coastal areas and maritime infrastructure has been described many times. However, the geological processes that can trigger such landslide events have not yet been fully established. In order to be able to conclusively assess the trigger potential of these processes, a quantification of the slope stability is indispensable. This requires a precise knowledge of the geotechnical and geological boundary conditions before and after the investigated landslide event, as well as the change in these boundary conditions caused by the alleged trigger mechanism. In order to make these described preconditions and the work process generally applicable, a universally adaptable methodology for the identification of trigger mechanisms was developed. Here, it is successfully applied to marine gas occurrence, which has recently been considered as a trigger mechanism due to the negative influence of enclosed gas bubbles on the shear strength of fine-grained soils. The constitutive model by Sultan and Garziglia (2014) is applied to simulate the gas-influenced undrained shear strength of a marine soil from a sediment starved margin on the Balearic Promontory and a range of Finite Element Limit Analyses (FELA) are conducted to determine the resulting loss of stability of different slope geometries. Within the scope of these calculations, the first set of Modified Cam Clay model parameters for a soil from the western Mediterranean is introduced. Based on the simulations, it can be concluded that marine gas occurrence decreases the overall stability of a slope compared to the saturated state. However, it also becomes obvious that the prevailing slope geometries with low inclinations are stable with a substantial capacity reserve for all simulated scenarios. Conclusively, gassy soil can be designated as a preconditioning factor decreasing the slope stability, as the state of failure can only be reached if the slope was in a precarious state before, or in combination with other impacts.

FLUID DYNAMIC ANALYSIS OF A MARINE SOIL IN JETTING EXCAVATION EMPLOYING RHEOLOGICAL MODELS: INFLUENCE OF DRILLING FLUID ON SOIL DEFORMATION

With the exploration of marine oil fields in deep and ultra-deepwater regions, the need for studying different methods of well construction has increased. Nowadays, the technique of laying conductive casing by jetting is the most widely used for the starting phase of a well in such conditions. In this scenario, in early layers, where the marine soil is in contact with seawater, this material can present itself as a fine mud, characterizing a cohesive non-drained soil, with low shear strength, being considered a material with viscoplastic behavior. Thus, as such, using fluid rheology to analyze it may represent a valid option; being possible to classify it as a Herschel-Bulkley fluid. The use of computational modeling and numerical simulation represent an alternative to understand the behavior of soil during jetting. In this context, this work focuses on developing a computational modeling of the jetting of marine soil, based on the soil fluid dynamics approach, using computational fluid dynamics (CFD - Computational Fluid Dynamics) software SIMULIA XFLOW, version 2020. This work aims to investigate the deformation in the seabed in response to an incident vertical jet using different drilling fluids, also modeled as viscoplastic materials. Drilling fluids suitable for jetting and a fluid with a higher specific mass were considered. For the proposed modeling of the soil and drilling fluids considered, the main parameters used were the yield point, consistency index, behavior index, and the boundary viscosity. The latter was necessary to implement the modified Herschel-Bulkley model used by the software. Results show that the excavated cavity presented a similar behavior for the drilling fluids suitable for jetting, indicating that the rheology of the drilling fluid does not interfere with the deformation of the soil. However, a significant influence on the profile of the excavated cavity was observed when implementing the drilling fluid of higher specific mass in the jetting, which deformed the soil at greater depths.

A new effective thermal conductivity model of methane hydrate-bearing sediments considering hydrate distribution patterns

In this work, a new effective thermal conductivity (ETC) model considering hydrate distribution patterns was proposed to study the effects of hydrate saturation (nh), distribution pattern and pore fluid. The ETC of methane hydrate (MH)-bearing sediments with liquid- saturated state (only water and MH in pores, i.e., “liquid-saturated” sediments), gas saturated state (only methane and MH, i.e., “gas-saturated” sediments) or hydrate-saturated state (only MH in pores, i.e., nh = 100%, “hydrate-saturated” sediments) were calculated by the proposed ETC models with the temperature 263.15∼278.15 K, the pressure 6 MPa and the porosity 47.64%. The calculated results show that the ETC of hydrate-saturated sediments is about 1.44±0.04 W·m−1·K−1; the ETC of liquid-saturated sediments ranges from 1.42 to 2.2 W·m−1·K−1, showing a weak negative correlation with nh, and a positive correlation with temperature. However, the ETC of gas-saturated sediments ranges from 0.15 to 1.45 W·m−1·K−1, which is positively correlated with nh, negatively (or positively) correlated with temperature at low nh (or high nh). Besides, the results suggest that the ETC increment caused by the temperature increase of 1 K is -3.6E-4∼2.34E-3 W·m−1·K−1 under the three hydrate distribution patterns and three above states, which can be seen as a weak dependence on temperature. The influence of distribution patterns on the ETC of gas-saturated sediments (with the same nh) is: cementing model > inclusion model > filling model. Due to the particularity of the structure of the supporting model, the ETC of sediments is mainly affected by sand content (vs), but weakly affected by hydrate content (vh) and hydrate growth mode. Increasing the same value of vs and vh, the ETC increment of the former is about 10 times that of the latter. Finally, the new ETC models are used to predict hydrate content of natural sea sand and marine soil samples, which provides a new idea for resource evaluation.

Experimental Study of the Engineering Mechanical Properties of the Foundation Soil for Offshore Wind Power Platforms

Most of the coastal beach zone in the world is rich in wind energy reserves and has great potential for offshore wind power development. However, the sedimentary environment in the coastal area is complex and changeable, and the nature of the foundation soil of offshore wind power platforms is weak and complex, which is quite different from that in the land areas. In order to systematically study the mechanical properties of marine foundation soils, a series of geotechnical tests are carried out on representative undisturbed seabed soils, such as basic laboratory geotechnical tests, bender element tests, undrained triaxial shear tests, and resonance column tests. The test results show that shear wave velocity (Vs) of marine silt and silty clay increases linearly with the buried depth; the stress-strain relationship curves of silty clay and silt present two different modes of development: strain hardening and strain softening, the undrained shear strength (Sd) of the two types of marine soils decreases with the increase of the void ratio (e), and both present a good single correlation. Based on the relationship between Sd and Vs from the laboratory test of disturbed seabed soils, an undrained strength evaluation method of undisturbed seabed soils under the current stratum conditions incorporating in situ shear wave velocity is established. The dynamic shear modulus (G) in the various strain ranges of undisturbed silty clay and silt increases regularly with the buried depth (H). Meanwhile, the maximum dynamic shear modulus (Gmax) linearly increases with the increase of H, whereas the attenuation relationship of G decreases with the increase of H. The prediction method of G based on buried depth is established with high accuracy.

Effects of underlying gas on formation and gas production of methane hydrate in muddy low-permeability cores

Hydrate reservoirs with underlying gas are generally accepted as the most promising energy resource for commercial exploitation. The underlying gas is an important part of the energy recovery of hydrate reservoirs. However, the gas production characteristics of hydrate reservoirs with underlying gas are rarely discussed. This paper aims to analyze the effects of underlying gas on the formation of hydrate and methane production behaviors by depressurization. In a core holder, marine soil obtained from the South China Sea was used to remold muddy low-permeability cores. The hydrate saturation of the muddy cores ranged from 25.2% to 48.3%. In this work, when the pressure difference between the underlying gas and the hydrate phase equilibrium is less than 2.6 MPa, the underlying gas pressure is the decisive factor for hydrate saturation. Besides, underlying gas can provide a relatively slow pressure drop rate for hydrate decomposition. The low permeability of the core caused by high hydrate saturation weakens the production of underlying gas and leads to the pressure gradient in the core. Hydrate decomposition front advances with the pressure gradient. Therefore, the production of underlying gas and hydrate decomposition are interdependent during depressurization. The experimental results demonstrated the existence of underlying gas could boost the exploitation potential and gas recoverability of hydrate reservoirs. These findings expand the understanding of joint exploitation characteristics and provide guidance in assessing the production potential for further researches and field exploitation of hydrate reservoirs with underlying gas.

Laboratory Evaluation of Undrained Shear Strength of a Soft Fine Grained Soils

The determination of undrained shear strength of soils is commonly achieved using triaxial testing in which specimen is carefully prepared before testing to maintain its original field condition. However, for soft soils preparing and handling specimens without causing any disturbance is a difficult job and may not always be successful. Other laboratory testing techniques can be adopted provided they can produce reliable results for such cases and can overcome the problem of pretest preparation process and hence avoiding any alteration of sample field condition. Extensive laboratory investigation on a soft marine soil recovered from sea bed offshore of Benghazi city, the testing program involves investigation of the basic geotechnical properties, focusing specifically on the determination of the undrained shear strength of such soils as determined by both the conventional unconsolidated undrained triaxial testing (UU) and the simple laboratory vane shear testing device (Miniature shear vane MV). The resulting shear strength obtained by UU-triaxial test, and resulting shear strength measured by Miniature shear vane MV were examined, compared and discussed on the light of other research works. Furthermore, the problems faced during testing soft samples in triaxial apparatus was also presented. The resulting undrained shear strength obtained by UU-triaxial test was found generally lower than that produced by Miniature shear vane MV which is attributed to sample disturbance before testing in triaxial. The study also demonstrates that despite of high scatter, the undrained shear strength obtained by MV can be reasonably comparable with the results of other investigations on soft soils.

Experimental Study of the Dynamic Shear Modulus Ratio and Damping Ratio of the Quaternary Sedimentary Soils in the Offshore Areas of the Yellow Sea

The effects of marine and continental sedimentary environments and geological ages on the dynamic shear modulus ratio and damping ratio of the Quaternary sedimentary soils in the offshore areas of the Yellow Sea were analyzed by using a resonant column device (GCTS, USA). The results show the following: (1) The G max of various marine soils increases with the depth and shows a typical linear relationship. (2) The marine transgression has significantly different effects on the dynamic shear modulus ratio versus the shear strain amplitude curves (i.e., G / G max ~ γ a curves) and the damping ratio versus the shear strain amplitude curves (i.e., λ ~ γ a curves) of the different soil types in the offshore areas of the Yellow Sea. The effects of marine transgression were strong on clays, moderate on silty clays, and minor on silts. (3) The geological ages have noticeable effects on the G / G max ~ γ a curves of the tested marine silty clays, marine silts, and continental silty clays, but the effects of geological ages on the λ ~ γ a curves are minimal. The fitting parameters and recommended empirical equations of the G / G max ~ γ a and λ ~ γ a curves for each type of the tested soils (silty clay, clay, and silt) were obtained mirroring the effects of sedimentary environments and geological ages.

A fluid mechanics approach to evaluating marine soft clay strength by a ball full-flow penetrometer

Ball full-flow penetrometer is widely used for testing the ultimate bearing pressure q of marine soil to evaluate the undrained shear strength su by the proposed bearing capacity factor N, and thus N is one of the primary concerns of marine geotechnical engineers. However, plastic constitutive model solutions of N resolved by using classical rigid-plastic materials described by the Tresca yield criterion are not suitable for evaluating the low-strength marine soft clays with viscous fluid characteristics. In this paper, the validated computational fluid dynamics (CFD) approach is used to simulate the interaction between the ball with smooth and rough surfaces and marine soft clays described by non-Newtonian fluids with shear thinning characteristics and rate effect. Based on this, the effects of the rate effect parameter λ, density and strength of the marine soft clay on N are systematically analyzed. Furthermore, during the ball's deep penetration, the equations of N considering different λ at rough and smooth ball surface conditions are established. Finally, the stress state of the marine soft clays around the ball and the mechanism of the rate effect leading to the variation of N are elucidated by the pressure distribution contours on the ball surface, the shear rate contours of the marine soft clay on the ball surface, and the velocity field contours of the marine soft clay around the ball, which provides a basis for the undrained shear strength su evaluation of low-strength marine soft clays.

Design of a Marine Sediments Resistivity Measurement System Based on a Circular Permutation Electrode

Marine sediments are rich in mineral resources, organic resources, and microbial life. The study of marine sediments is of great significance for the development and utilization of marine resources and understanding the life process. Resistivity is the overall characteristic of the electrical conductivity of marine sediments. Measuring the resistivity of marine sediments is helpful to ascertain the marine geological structure, study the distribution of marine mineral resources, and evaluate the marine soil environment. Measuring the resistivity of marine sediments is of great significance to promote marine exploration. At present, the resistivity measurement device on the market can be directly used to measure soil and water on land, but if used to measure marine sediments, it will be disturbed by seawater temperature and pressure, resulting in large errors. In this paper, a high-precision pressure-maintaining transfer system of marine sediment resistivity measurement instrument based on circular permutation electrode is designed, which can measure the resistivity of marine sediment samples after pressure-maintaining transfer. At the same time, a new type of circular permutation electrode measurement method is proposed, which makes the resistivity value more accurate, reduces the length of the probe appropriately, and saves the cost. By measuring the resistivity of marine sediments, the type of sediments can be inverted, which provides a way of thinking about the promotion of the research and development and utilization of marine resources.

Organicheskoye veshchestvo donnykh otlozheniy krymskogo i kavkazskogo poberezhiy (Azovskoye i Chernoye morya)

As part of the 113th cruise of the R/V “Professor Vodyanitsky”, research was conducted on organic pollution of bottom sediments in the coastal areas of Crimea and the Caucasus, as well as the water area in front of the Kerch Strait. Concentration of chloroformextractable substances was determined by the weight method and that of petroleum hydrocarbons was determined using infrared spectrometry. Both in 2020 and 2016 (the 83d cruise of the R/V “Professor Vodyanitsky”), properties of the bottom sediments of the Crimean and Caucasian coasts were typical of the marine soils of this region. This indicates that the studied water areas are generally in good condition. In accordance with the regional classification of bottom sediment pollution, the maximum concentrations of chloroform-extractable substances obtained for both the Black Sea and the Sea of Azov coast indicate pollution level III (23% of analysed samples). These values were found in bottom sediments in the Sevastopol water area (225 mg·100 g-1), in the coastal area of Cape Tarkhankut (120 mg·100 g-1) and Karadag (120 mg·100 g-1), the southern part of the Sea of Azov (125 mg·100 g-1) and Tuapse (110 mg·100 g-1). The content of chloroform-extractable substances in bottom sediments off the Black Sea coast of the Caucasus and the Sea of Azov coast is slightly lower than that off the Crimean coast. Pollution level II is assigned to bottom sediments in 46 % of the samples, with an average concentration of 72 mg·100 g-1 of air-dry solids. The rest (31 %) of the studied area was classified as conditionally clean (pollution level I, i. e. less than 50 mg·100 g-1). There has been a slight increase in the concentration of petroleum hydrocarbons in the bottom sediments of both the Black Sea and the Sea of Azov and their share in the total amount of chloroformextractable substances. In general, the level of pollution of bottom sediments by organic matter remained unchanged if compared with previous years, in particular with the data from 2016

Statistical Optimization of Prodigiosin Production by Plackett-burman Design for Bacteria Isolated from Indian Marine Soil

The current investigation was conducted to maximise the production of the natural anticancer drug from the microbe isolated from the marine soil sample of the Coromandel Coast of the Bay of Bengal region of India. Yellow to red colour pigmented microbes separated by crowd plate method. Bacteria are producing strong colour product subjected to future study. The isolated strains were detected based on biochemical, morphological, and genetic characteristics. Pigment formation was found to be influenced strongly by conditions of the environment. The water-insoluble pigment extracted by acidified methanol and showed maximum absorbance at 535nm. A statistical screening procedure was adopted to select the optimum condition to produce the pigment. The carbon, nitrogen, medium pH, growth condition temperature and revolution of agitation were screened using the response surface methodology statistical model. The near optimum conditions for the production medium were affected by the concentration of peanut, L-proline, percentage inoculum pH and incubation time. When these conditions were employed yield increased as two-fold as the concentration of prodigiosin 789 mg/l.

Investigations on Presence of Biopolymer Producing Microorganism in Marine Soils & Enhanced Potential of Marine Soil by Using Isolated Microorganism

Gujarat has a very extended coastal belt, and due to type, the properties of available soil in the coastal regions vary from place to place. These soil properties are not suitable for infrastructure development. Many techniques were already developed for the improvement of marine soil strength. Some of them are very costly; some method is not suitable due to high water table in the region. Some have adverse effects on aquatic life. This study has an approach to give sustainable, eco-friendly, and economical techniques to increase the unconfined compressive strength of marine soil of the different regions. The entire colonies available in soil are studied by series dilution and spread plate technique. Microorganisms produce exopolysaccharides (EPS) in excess carbohydrates, which provides by the screening method in nutrient agar broth (N. agar). Microbial Biopolymer such as exopolysaccharides can act as an eco-friendly binder of soil. EPS-producing organisms work as an environmentally sustainable method to improve soil strength. More exopolysaccharides-producing and fastest-growing microorganisms were selected by EPS extraction from all microorganisms found in a survey. The result was also compared with the unconfined compressive strength achieved by bio cement and a mixture of biopolymer and biocement. The biopolymer shows an increase in result (1.625– 1.891) times from 14 days to 28 days. Biocement showed an increase in the result, which ranges from (1.763–1.955), and the mixture of both shows a tremendous increment of (1.635-1.885).

Isolation of antibiotics producing bacteria from marine soil and comparative analysis of same with commercially available drugs

The isolation of antibiotic producing bacteria from marine soil and comparative analysis of same with ciprofloxacin and amoxicillin against staphylococcus aureus and Escherichia coli was carried out in a Microbiology Laboratory of Chukwuemeka Odumegwu Ojukwu University, Uli. This was done to isolate antibiotic producing bacteria and compare same with existing commercially available antibiotics with a view to using marine soil in the treatment of common bacterial infections. Soil samples were collected from Bonny Island Sea, Port Harcourt. One gram of mixed soil sample was serially diluted and spread-plated on nutrient agar plates. The representative isolates obtained were sub-cultured to get a pure culture. Morphological, biochemical, physiological characteristics of the bacteria were analyzed. Agar well diffusion was carried out. One isolate had a substantial antibacterial activity with 3.5mm zone of inhibition against two test bacteria used in the preliminary screening. The isolate was marked as Streptomyces (STR I) and was identified as Streptomyces griseus while other isolates did not show any antibacterial activity. Ciprofloxacin showed the highest antibacterial activity to both Staphylococcus aureus and Escherichia coli of 3.7mm and 4.0mm respectively while Amoxicillin showed antibacterial activity of 3.5mm and 2.7mm respectively. This reveals that antibiotic producing bacteria from marine soil are also effective in antimicrobial activity and could be used for antimicrobial chemotherapy.

Isolation of antibiotics producing bacteria from marine soil and comparative analysis of same with commercially available drugs

Isolation of antibiotics producing bacteria from marine soil and comparative analysis of same with commercially available drugs

Variation in Micro-Pores during Dynamic Consolidation and Compression of Soft Marine Soil

In this study, to explore the microstructure deformation mechanism of marine soft marine soil under cyclic loading, we analyzed the dynamic properties of soft marine soil under cyclic loading via dynamic consolidation compression testing. Then, using Image-Pro Plus (IPP) 6.0 image analysis software, and according to the dynamic consolidation compression test results and the images from a scanning electron microscope (SEM), we determined the weakening effect of soft soils under different consolidation confining pressures, different cyclic stress ratios, and different over-consolidation ratios. After dynamic consolidation and compression, the pore structure of undisturbed soft marine soil tends to compact, the degree of soil particle fragmentation intensifies, small pores increase, large pores decrease, the pores become more regular, and the distribution of pores is directional. Subsequently, for undisturbed soft marine soil, the higher the consolidated confining pressure, cyclic dynamic stress ratio, and over-consolidation ratio, the greater the damage to the pore structure, and the more obvious the structural weakening effect exhibited under cyclic loading.

Thixotropy of a Transparent Clay Manufactured Using Carbopol to Simulate Marine Soil

A transparent clay manufactured using Carbopol® UltrezTM 10 (simplified as U10) was introduced, and its manufacturing processes were briefly described. Both relative transparency (RT) and modulation transfer function (MTF) methods were used to quantify the optical character variation via soil thickness. The transparency of this new transparent clay was analyzed and compared with four traditional transparent materials. The thixotropic properties of this synthetic transparent clay were measured in detail through the laboratory vane test. An exponential function was used to describe the thixotropy and sensitivity of the clay. The results showed that the new transparent clay has a relatively higher optical transparency than the majority of previous materials. Good-fitting results showed a similar development trend in thixotropy for the synthetic transparent clay and the natural ones. Furthermore, the sensitivity of the transparent clay was low to medium, which can simulate marine soil. With higher optical transparency than and similar thixotropy and sensitivity as natural clays, Carbopol® UltrezTM 10 shows great potential as a substitute for natural clay and is expected to be widely used in model tests.