Cutoff Wall Research Articles

Effect of polyanionic cellulose modification on hydraulic and consolidation performance of sand-calcium bentonite slurry trench cutoff walls

Sand-bentonite slurry trench cutoff wall is one of the most common vertical barriers to retard the migration of contaminants. This study aimed to explore the hydraulic and consolidation performance of cutoff-wall materials containing polyanionic cellulose (PAC)-modified calcium bentonite (CaB) through a comprehensive laboratory investigation. First, physicochemical properties tests were conducted to demonstrate the superiority of PAC-CaB over CaB. Subsequently, modified fluid loss tests were conducted to investigate the effects of PAC modification and CaCl2 solution concentration on the chemical compatibility of CaB cake formed during slurry trench protection. Finally, slump, Atterberg limit, oedometer, and rigid/flexible-wall hydraulic conductivity tests were performed to evaluate the effect of PAC modification on the hydraulic conductivity (k) and compressibility of sand-CaB backfill. The results indicate that PAC can significantly enhance the impermeability of CaB cake when permeated with salt solutions. The 4 %PAC-CaB cake in 40 mM CaCl2 solution had the lowest k value (9.3 × 10−10 m/s), and was therefore recommended as the optimum proportion for trench protection. The addition of PAC considerably reduced the consolidation coefficient of CaB backfill and increased its compression index and swell index. Moreover, with the increase of PAC dosage from 0% to 0.2%, 0.4%, and 0.8%, the k values of CaB backfill decreased by 0.75, 0.96, and 1.29 orders of magnitude, respectively. The k values of PAC-CaB materials were lower than those of sodium bentonite materials, indicating that PAC is a promising modifier to achieve a low k value of CaB cake and sand-CaB backfill for slurry cutoff walls.

A meshfree large-deformation analysis method for geotechnical engineering based on the RBF field variable mapping technology

In this paper, a practical meshfree large deformation method (MFLDM) is proposed for numerical analysis in geotechnical engineerings, including: soil foundation, slop, dam, etc. The MFLDM leverages both the flexible nodal distribution in the meshfree method and the high stability in the arbitrary Lagrangian–Eulerian (ALE) framework. In each calculation step, two sets of Gauss points, fixed and moving Gauss points, are generated in the background mesh. In addition, the radial basis function (RBF) is used to map field variables, including stress, stain, and constitutive variables, between the fixed and moving Gauss points to achieve the field variable redistribution during the large-deformation analysis. The proposed MFLDM, which is written in C++ using the object-oriented programming approach, can be completely integrated into the self-development calculating system named GEODYNA and coupled with the finite element method (FEM) at the matrix level, which significantly broadens its practical application. The proposed model is verified by several numerical examples and compared with different constitutive models, including the linear elasticity model, ideal elastic–plastic model, and generalized elastic–plastic model. The comparison results verify the high accuracy, fast convergence, and good robustness of the proposed MFLDM. Finally, the proposed MFLDM is applied to a local large deformation analysis between the cut-off wall and the core wall on a deep overburden.

The cut off efficiency of sheet piles with variation of Water level: Al-hindiya barrage as case study.

Al-Hindiya barrage is an important project to ensure safety of structures is considered as one of the important projects in Iraq, so it’s very important to checking it’s the extent of the efficiency of the cut-off wall can be determined by calculating the amount of seepage flow that occurred under the structure in different conditions, such as the difference in water levels in the upstream and downstream, using the Geo-studio SEEP/W program by taking a natural analysis and a differential analysis. Cut off and a significant drop, and also when the most dangerous flood situation occurs at the greatest level in the Upstream In this case, all the gates must be opened, i.e., a quick descent into the origin. This case was studied, and the efficiency of the cut-off wall was proven in the most dangerous case, and it is considered one of the indicators of peace for the Al-Hindiya barrage The finite element method was used to investigate cutoff walls and downstream filters to control seepage, exit hydraulic gradient, and uplift forces for dams, The Al-Hindiyah Bridge was studied and the error rate was less than 1%, studying the unloading situation at the highest level at a time approved by the executing company, and delaying the unloading process at this time at the start of the project operation This case was analyzed by studying the uplift pressure, seepage rate, seepage velocity, gradient and discharge at the upstream, i.e. from a point close to the face of the sheet pile and a point far from the face of the sheet pile at the downstream we conclude through this case the efficiency of the sheet pile at the point located in the backside, which shows the efficiency of the sheet pile significantly The study proved that when facing the Al-Hindiya Bridge, the state of flooding, all gates must be opened at an average speed for a period of 12 hours to get rid of the water in excess of the permitted storage The study proved the efficiency of the sheet bale when confronting the flood situation and at different times, by calculating the safety factor 2.24 within the permissible limits. Recommendations for suitable combinations of upstream cutoff and downstream filter are provide.Recommendations for suitable combinations of upstream cutoff and downstream filter are provide

Geological and geotechnical characterization of Ziragn Dam sitting, northwestern Ethiopia

The goal of this study was to look at the geological and geotechnical conditions of the Ziragn dam, which would be built across the Ziragn river for irrigation purposes. The objectives of the study were to investigate and characterize the geological, hydrogeological, and seismicity condition, reservoir area, construction materials, and geotechnical situations of the dam site. During the physical investigation, geotechnical interpretations were done using the drilling logged data, laboratory tests as well as drilling core samples. Results of the study revealed that the area is characterized by slightly fractured massive basaltic rocks which are found at the dam axis and spillway area. The reservoir area is also covered by silty clay soils basaltic rocks and silty clay soil. The stream bed and the banks are made up of the same geological materials of basaltic rock. The basaltic rocks at the reservoir area are characterized by low permeability while the abutment areas were moderately fractured and weathered and the silty clay soil is characterized by medium to high plastic impervious soil. Based on the findings, the following recommendations are forwarded: (a) Design a masonry/concrete cut-off wall at the central portion of the dam. (b) On the left bank at the upstream, vertically jointed rocks permitted seepage problems, it needs cement grouting. (c)Rocks at the abutment sides show fractured and weathered which needs the removal of the surface and treatment by cement injection. (d) Even though the dam was micro it needs serious monitoring and follow-up during and after construction.

Analytical Model for the Design of Permeable Reactive Barriers Considering Solute Transport in a Dual-Domain System

A permeable reactive barrier (PRB) is an effective groundwater in situ remediation technology, and the design methods used for PRBs are significant in ensuring that they meet remediation goals. Steady-state analytical solutions are an effective tool to provide conservative and simple design methods. A steady-state analytical solution is proposed to describe organic contaminant transport through the PRB and aquifer in a PRB and cut-off wall system. The proposed analytical solution may serve as an effective tool to provide conservative and simple design methods. The shape factor (S) is introduced at the PRB-aquifer interface to investigate the effects of a PRB’s layout forms on its performance. The results show that the relative contaminant concentration at the point of compliance for a PRB with S=8 is 11 orders of magnitude larger than that without considering the shape factor. Effects of degradation, dispersion, and advection on PRB design are subjected to dimensionless analysis. Dimensionless analysis shows that degradation plays a key role in decreasing contaminant concentration in the PRB. In addition, increasing advection may promote contaminant transport from the source to the aquifer. Simplified solutions to estimate PRB thickness and source remediation time are derived for the practical design and performance evaluation of the PRB system.

Single-factor sensitivity analysis of earth dams with polymer cutoff wall under stress and seepage fields coupling

As a new anti-seepage reinforcement technology for small and medium sized earth dam, polymer cutoff wall has been increasingly used in engineering practice with good anti-seepage performance, strong deformation ability and convenient construction. However, the single-factor sensitivity of earth dams with polymer cutoff wall under stress and seepage fields coupling has not yet been well revealed. In this study, a 3D FE model of earth dam with polymer cutoff wall were established and the influence of polymer cutoff wall parameters on the performance of earth dam was studied by a single-factor sensitivity analysis method. The density, depth, thickness and position of polymer cutoff wall were regarded as the sensitive factors. The safety coefficient of the earth dam, the anti-seepage performance, the von Mises stress, and the horizontal deformation were used as evaluation indicators of the polymer cutoff wall. The sensitivity of the evaluation indicators to the sensitive factors were ranked based upon the sensitivity coefficient. The sensitivity of the aforementioned parameters on the earth dams was presented. The research conclusions may provide some basis for designing the polymer cutoff wall.

Experimental study on suffusion and contact erosion in double-layered alluvial foundation with a cut-off wall

Experimental study on suffusion and contact erosion in double-layered alluvial foundation with a cut-off wall

Hydro-mechanical behavior and microstructure evolution of red clay-bentonite backfills

Soil-bentonite (SB) cutoff walls have been extensively used as vertical engineering barriers to control groundwater flow and subsurface contaminant migration. As the pollution containment capability of the SB backfills is intimately related to the hydro-mechanical behavior, consolidation tests and hydraulic conductivity tests were carried out to investigate the effects of bentonite content on the hydro-mechanical behavior of red clay-bentonite backfills, and the microstructure evolution of backfills under vertical loading was evaluated based on mercury intrusion porosimetry (MIP) tests and field emission scanning electron microscope (FESEM) observations. The results of microstructure analysis also evaluated the influence of bentonite on the clay fabric which changed the relationship between hydraulic conductivity and void ratio. The results indicated that the void ratio and hydraulic conductivity decreased linearly with the increase of the effective consolidation stresses, and the compression index decreased with the increase of bentonite content. Meanwhile, the pore size distribution (PSD) curve of the backfill specimen almost turned into unimodal characteristics with only micropores distributed after consolidation. Additionally, the flow paths became more tortuous under compression which decreased the hydraulic conductivity. The montmorillonite aggregates in red clay-bentonite backfill formed into tortuous network structure which bound the clay aggregates together and effectively increased the tortuosity of flow paths.

Investigating Deformation Mechanism of Earth-Rock Dams with InSaR and Numerical Simulation: Application to Liuduzhai Reservoir Dam, China

Ground deformation is the direct manifestation of the earth-rock dam's hazard potential. Therefore, it is essential to monitor deformation for dam warning and security evaluation. The Liuduzhai Dam, a clay-core dam of a large reservoir in China, was reinforced with plastic concrete cut-off walls between 13 January 2009 and 29 May 2010, as it was subject to leakage and deformation. However, the deformation development and the mechanism of the dam are still unclear. In this study, the deformation fields before and after the reinforcement of the Liuduzhai Dam were yielded by using the Interferometric Synthetic Aperture Radar (InSAR) technique. Furthermore, a numerical simulation method was employed to obtain the dynamic seepage field of the dam during the InSAR observation period. The results indicated that the average deformation velocity and maximum deformation velocity are −11.7 mm/yr and −22.5 mm/yr, respectively, and the cumulative displacement exceeds 100 mm, which shows typical continuous growth characteristics in a time series. In contrast, the dam deformation tended to be stable after reinforcement, with the average deformation velocity and maximum deformation velocity being −0.4 mm/yr and −1.2 mm/yr, respectively, behaving as cyclical deformation time series. According to the results of InSAR and seepage analysis, it is shown that: (1) dynamic seepage was the main mechanism controlling dam deformation prior to reinforcement; (2) the concentrated load caused by construction and the rapid dissipation of pore water pressure caused by the sudden drop of the infiltration line were the reasons for the acceleration of deformation during and after construction; and (3) the plastic concrete cut-off walls effectively reduced the dynamic seepage field, while the water level fluctuations were the main driving factor of elastic deformation of the dam after reinforcement. This study provides a novel approach to investigating the deformation mechanism of earth-rock dams. Furthermore, it has been confirmed that InSAR can identify the seepage deformation of dams by detecting surface movements. It is recommended that InSAR deformation monitoring should be incorporated into future dam safety programs to provide detailed deformation signals. By analyzing the temporal and spatial characteristics of the deformation signal, we can identify areas where dam performance has degraded. This crucial information aids in conducting a comprehensive dam safety assessment.

The Chemical Compatibility of Sand–Attapulgite Cut-Off Walls for Landfills

Soil–bentonite cut-off walls have been widely used to control landfill pollution but they do not have good chemical compatibility with landfill leachate. Attapulgite can be substituted for bentonite in landfill cut-off walls. However, little is known about the chemical compatibility of attapulgite cut-off walls and leachate. This study experimentally investigated the chemical compatibility of attapulgite cut-off wall specimens with organic and inorganic contaminants and found that a sand–attapulgite cut-off wall has good chemical compatibility with organic contaminants. A CaCl2 solution was used to represent inorganic contaminants, and chemical oxygen demand (COD) was used as an indicator of organic content. The hydraulic conductivity of the cut-off wall initially decreased and then increased to become approximately constant as Ca2+ concentration increased. Changes in COD concentration were divided into a decreasing stage (0–10,000 mg/L) and a constant stage (10,000–40,000 mg/L). The increase or decrease in hydraulic conductivity was by no more than one order of magnitude. The increase in the hydraulic conductivity of the sand–attapulgite cut-off wall is explained in terms of bound water content and pore structure. An increase in Ca2+ concentration decreased the bound water content of the cut-off wall while the CaCl2 solution increased macropore and mesopore volume and decreased small pore volume in the sand–attapulgite cut-off wall. The purpose of this study was to elucidate the chemical compatibility of a sand–attapulgite cut-off wall with organic and inorganic contaminants and to increase the understanding of the interactions between the cut-off wall and the contaminants. The results of this research are informative for improving the application, design, and construction of sand–attapulgite cut-off walls.

Two-phase changes in workability of sand-bentonite mixture triggered by seawater and binder during seepage cut-off wall construction in marine environment

Phenomenal sea level rise is exacerbating the risk of seawater intrusion in coastal areas, especially those with sandy soil, causing land erosion. Seepage cut-off walls made of in-situ sand, bentonite and binder can be employed. However, the presence of salts in soil is detrimental to water retention ability of bentonite, which can be aggravated by binder-induced cation exchange reactions, causing constructability issues for two-phase cut-off walls. Therefore, this study aims to evaluate the workability properties, including flowability and bleeding of sand-bentonite-binder mixture in seawater environment. The mechanism of decrease in water retention of bentonite has been investigated using Atterberg limits, X-ray diffration (XRD) and scanning electron microscope (SEM) analyses. In phase-one construction, seawater significantly increased flowability of sand-bentonite mixture. During the second phase, binder inclusion increased flowability even further. Given comparable flowability, the bleeding in sand-bentonite-binder mixture containing seawater was much greater than in the non-seawater environment. This was ascribed to a loss in water retention capacity of bentonite, in which external cations from seawater and binder exchanged with bentonite, resulting in reduction in liquid limit. The Na-based montmorillonite was transformed into Ca-based montmorillonite, causing the morphology of bentonite particles to flocculate. Despite this, the study discovered a feasible sand-bentonite-binder mixture including reactive magnesia (MgO)-activated ground granulated blast-furnace slag (GGBS) and seawater-resistant bentonite, which impeded the increase in workability.

Role of Multidetector Computed Tomography in Differentiation of Benign and Malignant Cavitary Lung Lesions With a Histopathological Correlation: A Retrospective Cross-Sectional Study.

Introduction Cavitary lung disease has a wide range of differential diagnoses, which include both benign and malignant lesions. Imaging differentiation of benign from malignant cavitary lesions has always been a challenge due to overlapping imaging findings. The present study describes the most accurate multidetector computed tomography (MDCT) findings that could help in differentiating benign from malignant conditions in correlation with the histopathological reports. Methods This retrospective study was carried out on diagnosed cases of cavitary lung lesions on MDCTfrom January 2022 to February 2023. We evaluated the number of cavitary lung lesions, their location with respect to lung segment/lobe, the maximum diameter of the largest lesion, the maximum wall thickness of the largest cavity, and additional findings associated with these lesions. Measurements of the maximum wall thickness were plotted on a graph. Statistical analysis was done, and a receiver operating characteristic curve (ROC) was calculated to find the accurate cut-off wall thickness for malignant and non-malignant lesions.These findings were then correlated with the histopathological report. Results A review of the MDCT scans of 47 patients was done; 30 (63.8%) of those were male with a mean age of 47.93±14.68 (SD) years while 17 (36.2%) were female with a mean age of 52.53 ±18.38 (SD) years. Out of 47 patients, 27 (57.4%) had benign lesions and 20 (42.5%) had malignant lesions. Significant differences (p<0.05) were found between benign and malignant lesions while comparing the averages of maximum wall thickness (8.1 mm and 14.5 mm, respectively) and the irregular inner margin of the largest cavitary lesions. The presence of consolidation and centrilobular nodules correlated significantly (p<0.05) with the benign nature of cavitary lung lesions. The maximum cut-off wall thickness was <6 mm and >17 mm for the differentiation of benign from malignant lung lesions, respectively. Conclusions The maximum wall thickness and irregular inner margin of cavitary lung lesions was a good indicator for the differentiation of benign and malignant etiologies on MDCTwhile consolidation and centrilobular nodules favoured the benign etiology more.

Evaluation of fault rupture propagation through earth dams subjected to reverse faulting: Outcomes from centrifuge simulation

Although permanent ground movement can cause devasting damages to the infrastructures, contributions assessing the effect of faulting on earth dams are limited with no notable experimental outcomes. This paper aims to provide conceptual information by investigating the response of earth dams with a clayey core subjected to reverse fault rupture using centrifuge experiments. The influence of the earth dam's location on the fault tip and the effect of alluvial foundation thickness beneath the dam was addressed by eight centrifuge tests at 60-g centrifugal acceleration. One model also explored the fault rupture-earth dam interaction considering a soil-cement cut-off wall beneath the center of the core. Distortion, sliding, and rotation of cores were observed as consequences of reverse faulting depending on the point of intersection between the dam body and fault trace. An increase in the core deformation was also captured for dams on thinner foundation layers. The freeboard height of the dam also decreases by 48%–90% of the vertical fault throw and should be considered in the design phase to avoid overtopping.

A Modified Strain Softening–Hardening Constitutive Model for Plastic Concrete Cut-off Wall

A Modified Strain Softening–Hardening Constitutive Model for Plastic Concrete Cut-off Wall

PbCl2 effects on the strength and permeability of plastic concrete cutoff walls

Plastic concrete walls are widely used in landfill and contaminated site pollution control engineering. Considering the prevalence of heavy metal lead ions contaminating the site, lead ions can affect the strength and permeability of plastic concrete walls. To this end, an experimental study on the effect of PbCl2 concentration on the strength, hydraulic conductivity and physico-chemical property indicators (pH and electrical conductivity) of plastic concrete walls composed of cement, bentonite, sand and PbCl2 solutions was carried out at different mix proportions and curing ages. The results show that the strength and pH of plastic concrete decrease with increasing PbCl2 concentration, and the hydraulic conductivity and electrical conductivity increases with increasing PbCl2 concentration at the same mix proportion and curing age. At the same PbCl2 concentration, the strength of plastic concrete increases with increasing plastic concrete cement content and curing age, and the hydraulic conductivity decreases with increasing plastic concrete cement content and curing age. Meanwhile, both pH and electrical conductivity decrease with increasing curing age, and both pH and electrical conductivity (σ) increase with increasing cement content. Consideration of pH and electrical conductivity (σ) can reflect the type of plastic concrete product and the degree of hydration reaction, which further reflects the degree of compactness and pore size of plastic concrete, thus affecting the strength and permeability of plastic concrete. Therefore, for plastic concrete with three cement contents, the strength of plastic concrete increases with increasing pH/σ, and the hydraulic conductivity decreases with increasing pH/σ at different PbCl2 concentrations and curing ages. In addition, pH/σ shows a good exponential function with plastic concrete strength and hydraulic conductivity.

A Universal Graphical Solution to Calculating Seepage in Excavation of Anisotropic Soils and Non-Limited Scenarios

The interaction between groundwater and civil engineering works is a key aspect in geotechnical design. In the case of excavations confined in sheet pile walls, steel sheeting, diaphragm walls, cut-off walls, or cofferdams, this design requires the estimation, among other soil mechanics properties, of the groundwater flowing into the excavation (seepage) caused by piezometry depletion. Numerical methods, graphical solutions, and analytical procedures are the methodologies traditionally used to solve this issue, solutions of which require an understanding of basic soil mechanical properties, hydraulic conditions and structure geometry. In this work, the discriminated non-dimensionalization technique is applied to obtain, for the first time, the dimensionless groups that govern the seepage, in anisotropic conditions, in large-scale scenarios where groundwater flow is not conditioned by impervious bedrock or the length of the back of the wall: π1=ab,π2=kxb2kyc2 and, π3=T/b. Numerical simulations are carried out to check the validity of dimensionless groups and to develop three sets of type curves that relate to these groups. Once the physical and geometrical data are known, the seepage (Q), the characteristic depth (T*) and the characteristic horizontal extension (L*) can be directly and easily calculated from these abacuses. The influence of anisotropy on the characteristic lengths is also addressed.

Hydraulic Conductivity, Microstructure, and Compositional Changes of Sand–Bentonite Backfill in Cutoff Walls Exposed to Organic Acids

Leachate, consisting of organic acids such as acetic acid (AA) and oxalic acid (OA), commonly is released into groundwater from municipal solid waste dumps and uncontrolled landfills. Slurry trench cutoff walls commonly are used to contain such contaminated groundwater, thereby protect the surrounding public and the environment. However, no studies have assessed comprehensively the effects of organic acid–laden groundwater exposure on the hydraulic conductivity and microscopic characteristics of sand–bentonite (SB) backfill in the cutoff walls. Several series of free swell, liquid limit, and flexible-wall hydraulic conductivity tests were conducted to quantify the effects of AA and OA exposure on the free swell index of bentonite and hydraulic conductivity and liquid limit of SB backfill. Results showed that the free swell index of bentonite and the liquid limit of SB backfill decreased with increasing concentrations of AA and OA. Exposure to AA yielded a lower free swell index of bentonite and liquid limit of SB backfill than those of OA with the same concentration. Increasing concentrations of AA and OA resulted in an increase in the hydraulic conductivity of SB backfills. Exposure to AA yielded higher hydraulic conductivity of SB backfill than OA with the same concentration. Mechanisms for increased hydraulic conductivity under organic acid exposure were ascertained based on the microstructure and compositional changes quantified by field-emission scanning electron microscopy (FESEM), mercury intrusion porosimetry (MIP), X-ray diffraction (XRD), X-ray fluorescence (XRF), cation exchange capacity (CEC), transmission electron microscopy (TEM), and Fourier-transform infrared spectroscopy (FTIR) analyses.

Research on plugging treatment of flooded mine: Determination of plugging location and optimization of anti-washout underwater concrete ratio

A high-quality underground copper sulfide mine in Africa has been flooded for a long time. It is proposed to use underground plugging method and stage drainage to recover underground copper sulfide ore resources. In this paper, 3DMine software is used to establish a three-dimensional mine model, analyze the spatial relationship and connectivity between SS30 safety pillar, roadway engineering and goaf, and then determine the location of water blockage. Then, the anti-washout underwater concrete is proposed for the construction of the cut-off wall. The ratio of anti-washout underwater concrete was designed by a three-factor and three-level orthogonal test, and the optimal ratio of anti-washout underwater concrete was obtained by combining range analysis, variance analysis, SPSS multiple linear regression analysis and MATLAB three-dimensional visualization. The results show that the sealing position is more suitable near the SS30 security pillar (610L, 820L, 1120L, 1440L, 1900L, and 1930L). The optimum proportion of anti-washout underwater concrete is water-binder ratio 0.45, anti-washout content 1.5%, sand ratio 42%. The research results can provide theoretical guidance for the treatment of similar flooded mines, so that the underground flooded mineral resources can be recovered safely and economically.

Finite-difference model for two-dimensional transport of degradable organic contaminants in a buffer layer-cutoff wall-aquifer system accounting for the consolidation behavior

Consolidation changes the geotechnical properties of a cutoff wall with depth. However, current research in transport theory fails to account for this factor. In this paper, a model for two-dimensional transport of degradable organic contaminants in a buffer layer-cutoff wall-aquifer system is developed, which takes the impacts of consolidation behavior into account for the first time. The finite-difference approach is employed to address this model, and its reasonableness is exhibited by the comparative analyses of three-different scenarios. Following this, a case-study on the barrier performance shows that accounting for the cutoff wall’s consolidation behavior prolongs the defined breakthrough time tb compared to when it is neglected. When a change in the cutoff wall consolidation parameter increases the horizontal and vertical effective stresses, its anti-fouling effectiveness is enhanced. Moreover, reducing the depth of the maximum inflow boundary concentration and increasing the concentration distribution range result in a decrease in tb. When the degradation half-life ≤ 400 years, the degradation effect should be considered to provide an accurate assessment of the cutoff wall’s longevity. For the “enclosure” cutoff walls, the appropriate thicknesses of the buffer layer and the cutoff wall can be determined based on the site environment and the construction cost.

Seepage Analysis and the Reservoir Water Pollution Potential under Vertical Dam Structure Planning

A prospective resolution to the intricate predicaments of flooding, sanitation, and the availability of unprocessed water for the populace of Jakarta residents is the implementation of the coastal reservoir paradigm. This paradigm entails harnessing the latent capacity of the Cisadane River flow and its subsequent storage within a retention pond, and then subjecting it to reprocessing to serve as a viable source of raw water. The selection of a vertical seawall design was based on the objective of creating an effective barrier between the reservoir and the sea, while also considering several environmental factors. This design was selected with the aim of minimizing the need for extensive soil excavation and rock placement. However, it is important to note that the risks of construction failure associated with seepage under hydraulic structure and dam stability pose significant challenges. Besides preventing saltwater intrusion and maintaining the integrity of the reservoir as a freshwater source, dam must be designed to mitigate potential seepage failure and intrusion issues. To address these concerns, this study employed numerical simulation using the SEEP/W and CTRAN/W software. The simulation was carried out to analyze seepage discharge under a vertical dam and predict potential seawater intrusion into the reservoir. The dam was examined over a ten-year period, with varying embankment widths of 10m, 20m, and 30m. The analysis considered changes in water level (ΔH) and the addition of a cut-off wall at depths of 5m, 10m, and 15m. The obtained results showed that seepage discharge rates amounted to 3,14x10-4 m3 s-1, 2,67x10-4 m3 s-1, and 2,50x10-4 m3 s-1 for embankment widths of 10m, 20m, and 30m, respectively, under a 1m level difference condition. Following this, the safety factor for piping on vertical embankment was determined as 1.10, 1.34, and 1.39 for widths of 10m, 20m, and 30m, respectively. This factor was found to increase to 4.03 when the embankment distance was widened, and a 15m deep cut-off wall was installed. It is important to note that the seawater intrusion model predicted a seawater concentration of 65,12 g m-3 at the bottom for an embankment width of 10m, while no intrusion was observed at widths of 20m and 30m with ΔH=1m. This study aims to assess potential risks of piping due to seepage and seawater contamination at the Cisadane Estuary.&#x0D;