Vertical Drainage System Research Articles

The technology of using a jet pump to increase the efficiency of vertical drainage

Vertical drainage systems, which rely on pumps and tube wells, are widely recognized for their effectiveness despite drawbacks such as high costs and significant energy consumption. In a recent study, the integration of a jet pump into vertical drainage systems was explored to enhance their efficiency. A specialized laboratory setup was developed to examine the use of a jet pump within these systems. The research focused on understanding how the diameter of the pressure pipe affects the jet pump’s suction capabilities. It was found that the jet pump operated at its highest efficiency, 50%, with a pressure pipe diameter of 40 mm. Statistical analysis of the laboratory data led to the formulation of a relationship for estimating both the suction capacity and suction height of the jet pump in the enhanced vertical drainage system.

Flood Risk Reduction Strategy With Vertical Drainage In Medan City, Indonesia

As the population of a city increases, there will be excessive exploitation of nature, uncontrolled land use change, and a decrease in the environment’s carrying capacity. These impacts cause flood disasters to increase in quantity and quality. Floods are still difficult to predict and avoid. Medan City is still haunted by the same problem as other cities in Indonesia, namely flooding. The government has focused on flood management by building a horizontal drainage network system, normalizing rivers, building embankments, but flooding still occurs frequently. Therefore, vertical drainage is needed for flood management. Vertical drainage drains surface water directly into the soil layer that horizontal drainage cannot accommodate. This research aims to study the ability of vertical drainage in Medan City to reduce flood risk. Based on the test results, vertical drainage has a discharge of 0.812 liters/second. Based on technical calculations, vertical drainage can distribute potential rainwater collected on the surface and with the addition of possible water from other sources at the research site within 9 minutes 1 second until it runs out as much as 440 liters. As a result, one vertical drainage system can effectively accommodate an area of 25 m2.

The Integrated Use of Heavy-Metal Pollution Indices and the Assessment of Metallic Health Risks in the Phreatic Groundwater Aquifer—The Case of the Oued Souf Valley in Algeria

In this research, contamination levels and the spatial pattern identification, as well as human and environmental health risk assessments of the heavy metals in the phreatic groundwater aquifer of the Oued Souf Valley were investigated for the first time. The applied methodology comprised a combination of heavy-metal pollution indices, inverse distance weighting, and human health risk assessment through water ingestion on samples collected from (14) monitoring wells. The contamination trend in the phreatic aquifer showed Al > B > Sr > Mn > Fe > Pb > Ni > Cr > Ba > Cu > Zn. Similarly, the enrichment trend was Al > B > Sr > Mn > Ni > Pb > Cr > Ba > Cu > Zn. Ecologically, most of the analyzed metals reflected a low potential ecological risk, except for two wells, S13 and S14, which represented a considerable and high ecological risk in terms of Pb. According to the applied grouping method, the samples in the first group indicated a lower risk of contamination in terms of heavy metals due to their lower concentration compared to the second group. This makes the area containing the second group’s samples more vulnerable in terms of heavy metals, which could affect urban, preurban, and even agricultural areas. All of the samples (100%) indicated the possibility of potential health risks in the case of children. While six samples showed that the non-cancer toxicity risk is considered low, the rest of the samples had high Hazard Index (HI) values, indicating the possibility of health risks occurring in the case of adults. The constructed vertical drainage system is acting as a supporter and accelerator of the pollution levels in the shallow groundwater aquifer. This is due to its contribution to the penetration of different pollutants into this aquifer system, depending on the residence time of the water, which appears to be long within the drainage system.

How energy is consumed in vacuum preloading treatment of soft ground

The vacuum preloading method is commonly used to improve soft soils; however, it has rarely been studied from the perspective of energy consumption. The work done by the vacuum pump in the vacuum system can be consumed in various ways, including seepage consolidation of soil, water discharge along prefabricated vertical drains and horizontal drainage system (i.e. sand blanket or horizontal pipes), extraction of the air sealed in the drainage system and air leakage from the atmosphere. Equations governing these aspects of energy consumption were derived in this study. A theoretical model of the energy consumption of the vacuum preloading method was established and then solved to quantify the specific forms of energy consumption. Theoretical predictions and laboratory results demonstrate that the energy consumptions of seepage consolidation and water discharge are negligibly small compared with the total work by the vacuum pump, and most of the work done by the vacuum pump in the vacuum system is consumed during the extraction of leaked-in air.

Assessment of Spatial Distribution and Temporal Variations of the Phreatic Groundwater Level Using Geostatistical Modelling: The Case of Oued Souf Valley—Southern East of Algeria

Since the beginning of the 1980s, several regions in the northern Sahara of Algeria have been confronting the rising groundwater. Among all these regions, Oued Souf Valley represented one of the most acute affected by this phenomenon. Due to the natural topography and the insufficient/weakness of water management and miscoordination between different sectors that are represented by intensive exploitation of deep groundwater reservoirs which returns to the shallow aquifer, absence of sewage and drainage network, leakage from drinking water supply system, the groundwater has raised to the surface or near to the surface, affecting the traditional cultural environment and urban areas and degrading all socio-economic aspects of the Oued Souf habitants. To preserve the Oued Souf environment, a vertical drainage system has been constructed. Consequently, in this research, an evaluation of the vertical drainage system performance and its impact on groundwater level stabilization has been performed by mapping the water table of the phreatic groundwater level using geostatistical modeling using ordinary kriging (OK) interpolation method, which has been applied to analyze the spatial and temporal structure of groundwater level fluctuation. Meanwhile, hierarchical cluster analysis (HCA) was applied for grouping the wells based on the groundwater fluctuations for 2008, 2009, 2014, 2016, 2018, and 2021. However, the vertical drainage system reflected a significant decline of groundwater from 2009 to 2018 due to the important drained volumes through it but another rising phenomenon might be threatening the region in the near future and this is what was indicated in the 2021 groundwater level data. Cluster analysis has generated four groups based on their fluctuation means that are increasing from the first group to the fourth group ascendingly. The first cluster grouped the drains that have a shallow depth (average mean of 5.91 mbgl) and declined over the clusters. The clusters are spatially combined with significant separation of the fourth cluster which represents the deepest group (12.89 mbgl). Based on this research, several factors are influencing the stability of the phreatic groundwater level and even the performance of the drainage system, the most important of which is the overexploitation from deep groundwater reservoirs such as complex terminal and continental intercalary (in drinking and irrigation) and even the illegal use of the phreatic groundwater with important quantities for irrigation and illegal industries.

Analysis of the Smear Zone Effect due to PVD Installation on the Embankment Consolidation Process with 2D and 3D Plaxis

The method of preloading and vertical drainage is one of the popular methods used to increase shear strength of soft soil. Initial loading is carried out with the aim of consolidating the soil layer with a large or equal load greater than the load that will be carried by the ground both during and after construction. While vertical drainage can speed up the evaluation process. The development of a vertical drainage system is the use of PVD (Prefebricate Vertical Drain). PVD is installed to drain the air that is dissipated in the preparation process. Analysis to compare the settlement that occurred in the Reklamasi Peti Kemas Belawan Fase II project with modeling on Plaxis 2D and 3D with and without using the smear zone effect. From the analysis, the settlement that occurred on consolidation process with Plaxis 2D modeling with and without the effect of the smear zone effect was 2,288 meters and 1,922 meters while the 3D Plaxis modeling obtained 2,077 meters for analysis without changing the effect of the smear zone and 1,930 meters for analysis with calculate the effect of the smear zone.

Laboratory and Field Experimental Study on the Vacuum Preloading Method with Pumping and Discharging

Negative vacuum pressure hardly reaches deep soils due to the drain board bending and serious blockage with the existing vacuum preloading methods (VPMs), thus resulting in poor reinforcement relative to practical engineering applications. To address this issue, this paper proposes a vacuum preloading method with pumping and discharging (a new dredger filling foundation processing technique based on vacuum preloading). This new VPM is developed through technological improvement and plastic drain board innovations in traditional VPMs. The new VPM uses a plastic vertical drainage board with double drainage channels, and the core board is in a “tic‐tac‐toe” shape with a hollow centre and square pipeline channels. It can execute air and water drainage. Vacuum transfer holes were set at two grooves, every 2‐3 m from the central pipeline of the core board. Grooves at two sides of the core board and filter membrane were rolled together to improve drainage. In addition, the vacuum pipe, tube connector, and core board centre of the vertical plastic drainage board were connected directly and securely. A stereoscopic vacuum transmission system composed of a horizontal and vertical drainage system was built. In this vacuum transmission system, the transfer route was shortened, and the loss of vacuum along the route was decreased. The negative vacuum pressure was transferred to different soil depths through the central pipeline of the core board to accelerate the dissipation of pore pressure in soil mass and prevent vacuum pressure loss caused by drainage board bending, thus improving the reinforcement effect. Dredger filling silt foundation reinforcement by VPM and VPM with pumping and drainage were compared in laboratory simulations and field tests with different drainage boards. Test results show that the loss of vacuum pressure along the drainage path was relatively smaller in the new physical vapor deposition (PVD), and the pressure transfer efficiency was increased. Deep soil mass was reinforced effectively by using the new PVD. After reinforcement, the physical and mechanical properties of soil layers were improved. Moreover, soil strengths were remarkably improved, with sharp reductions in natural moisture content and porosity. Then, the transfer law of vacuum on different drainage boards and the reinforcement mechanism of VPM with pumping and drainage were analysed. Research conclusions show the superiority of VPM with pumping and drainage in terms of effectiveness and soft foundation reinforcement. This study provides a theoretical basis for the application and development of the new VPM.

ВЗАЄМОДІЯ ДРЕНАЖНИХ СВЕРДЛОВИН У ПРОТИФІЛЬТРАЦІЙНИХ ЗАВІСАХ

The decrease of water levels in the drainage wells of the coastal anti-filtration drainage system with the siphon method of water intake from them was analyzed. The interaction of water-lowering wells with different depths and located at variable distances from each other is considered, which makes it possible to ensure uniform drainage from each well and to achieve a steady decrease in the level of groundwater over the entire length of the antifiltration drainage system.The results of the performed analytical studies are presented. The example of the Kamyanka-Dniprovska's anti-filtration drainage system shows that the decrease in water levels in wells at the same flow rate of pumped water depends on their hydraulic interaction, hydrogeological conditions of water filtration from the aquifer and the distance of the antifiltration drainage system from the bank-side. The results obtained indicate that the highest level of water depletion of the coastal vertical anti-filtration drainage system line with siphon drainage from wells is achieved at a distance of a number of wells from the Kakhovsky reservoir bank-side a = 100 m, at the same water flow rate from each of the drainage wells (Q = 604,8 m3 /day), located at different distances from each other. The highest rate of additional reduction of water obtained through mutual hydraulic action was obtained in the 7th well, which has a depth of 14,9 m, and it is located at a distance of 100 m from the 6th well and at a distance of 110 m from the 8th well. The lowest indicator of the level of groundwater reductions at different indicators of the distance of a number of drainage wells to the bank-side a (30, 50, 80, 100 m) is observed in the first well, farthest from the water collection well.

Effect of Vertical Drains on Strength and Deformation Characteristics of Lithomargic Clay

During olden days, construction used to be carried out only on the sites having good strength. But now-a-days availability of sites with favourable properties are limited. So, there is a need to modify the properties of subsoil using different types of Ground Improvement Techniques. Depending upon the nature of soil, a suitable economical technique needs to be adopted. Soft soils have weaker strength and they are highly compressible and take a lot of time for settlement. So, these are typically problematic for construction. There is a need to improve the condition by accelerating the rate of consolidation. To achieve higher rate of consolidation, it is important to develop shorter paths for movement of the water. A vertical drainage system can be provided to accelerate the rate of consolidation and help to minimise excess pore pressure in the sub-soil. As a result of this, a stable situation is reached more quickly. Thus to enhance the strength of the soil and to accelerate the consolidation rate, vertical drains of different diameters and with varied spacing are employed. The improvement in properties of soft consolidating lithomargic clay is experimentally tested with vertical sand drains in developed prototype. The vertical sand drains installed with 1.905 (0.75 inch) diameter and 6 cm spacing is more effective in increasing Ultimate Bearing Capacity (UBC) of soil and also the rate of settlement of 35.26 % is significant up to 60 kg of preloads. Thus problematic lithomargic clay can be improved in its strength and settlement characteristics.

Field Test and Numerical Simulation for Coordinated Deformation of New Subgrade and Old Embankment Adjacent to River

With the development of the economy in China, original roads may be unable to cope with the existing traffic. The expansion of the old embankment is the core problem for road expansion. Soft foundation differential settlements and pavement cracking along the joint between the new subgrade and old embankment often emerge after construction, especially during the operational period of the road. The Binjiang Avenue Project in Nanjing, China, is taken as a research example in this paper, and a typical test zone of about 300.0 m in length was selected to conduct research work through in-situ tests. The coordinated deformations of the subgrade combined with the old embankment under conditions of consolidation by drainage were researched using in-situ tests and numerical modeling. During the process of numerical modeling, the vertical drainage system in the compressible soft ground layers was simplified to be represented as the drainage band model and the equivalent sand-wall model. In addition, a soft ground creep model was adopted to calculate the deformation of the subgrade with the construction process. A comparison of the results between field tests and numerical simulations was carried out. The results show that there is good uniformity for both. Based on the results, three indexes for the new and old subgrade, such as the differential settlement, total settlement and post-settlement, should be viewed as the basis for the design and construction of the new subgrade and old embankment. Additionally, it was found that the soft ground model, drainage band model and equivalent sand-wall model are all completely suitable for the numerical modeling of the soft ground reinforcement subgrade. These results also provide a theoretical basis for the construction method of similar projects.

Failure of a Vertical Drainage System Installed to Fight the Rise of Groundwater in El-Oued Valley (SE Algeria): Causes and Proposed Solutions

El-Oued Valley suffers from the problem of rising groundwater which affects agricultural and urban areas and degrades all aspects of the socioeconomic life of its inhabitants. This problem, which appeared in the 1980s, is primarily a result of overexploitation of deep groundwater, lack of sanitation network, and discharge of wastewater directly into the unconfined aquifer. To solve this problem, a megaproject was carried out, based on the principle of sewerage, to drain and evacuate excess water after treatment to a discharge site 70 km north of the region. In this project, the blade of groundwater above elevation of 60 m should be drained through wells of a vertical drainage system. However, the expected results have not been achieved in most affected cities, where the groundwater level continues to rise. Herein, we propose a solution to this problem, based on a new explanation of the hydrogeological structure of the unconfined aquifer that drives the rising groundwater to the surface. The main part of this research is based on interpretation of well tests carried out in wells of the vertical drainage system.

Improvement of Traditional Mining Tailings Storage Facilities

Traditional mining tailings storage facilities may generate calamities and contaminants that cause the infiltration of tailings dam and even lead to dam failures. In view of this, new tailings storage facilities are designed in this paper by combining traditional tailings storage facilities with barrier systems including a vertical drainage system, a compound liner system, a fluid collection system and a caps system. With the vertical drainage system, water in contact with tailings can be transported into the fluid collection system. With the compound liner system, fluid can find a waterproof environment, which prevents the contamination of the environment such as surface water, groundwater, soil and food chain. With the fluid collection system, water in contact with tailings and fluid can be collected and removed to wastewater treatment plants, thus avoiding dam failure and AMD generation caused by the reaction of iron sulphides with water and oxygen.

Results from the Dutch Ecobeach pilot project

Between the beginning of 2007 and the beginning of 2011 a trial was carried out with the innovative vertical beach drainage system Ecobeach at the beach of Egmond aan Zee in the Netherlands. The pilot consisted of a field experiment, in which a statistical analysis was executed for some coastal state indicators, and a scientific part, in which a possible working principle of the system was investigated.

RESULTS FROM THE DUTCH ECOBEACH PILOT PROJECT

Between 2007 and 2011 a trial has been carried out with the innovative vertical beach drainage system Ecobeach at the beach of Egmond aan Zee in the Netherlands. The pilot consisted of a field experiment, for which a statistical analysis of measured coastal state indicators was executed, and a scientific part, in which a possible working principle of the system was investigated. A significant increase in beach volume has been found during the test period. Vertical beach drainage could be applied in combination with foreshore nourishments on eroding coastlines.

Evaluating the PEM passive beach drainage system in a 4-year field experiment at Egmond (The Netherlands)

The PEMs' (Pressure Equalizing Modules) passive vertical drainage system was tested at the coast just south of Egmond (The Netherlands) from November 2006 to December 2010. The present study aims at providing qualitative and quantitative insight into the impact of the PEMs on the nearshore morphological development at Egmond. The evaluation is based on a comparison of the annually observed temporal evolution of the nearshore morphology prior, during and after the PEM installation period. To this end a number of aggregated volumetric profile parameters derived from the surveys were compared for the test area and for an adjacent area which acted as a reference. Besides the PEMs, the study area is also influenced by beach and shoreface nourishments. Therefore, the nourishments carried out just north and south of the Test and Reference areas in 2004 and 2005 prior to the installation of the PEMs were specifically considered in the analysis. From 2008 onward the morphological behavior of the nearshore zone was dominated by the alongshore coherent net offshore migration of the multiple bar system and no obvious feeding of sand from the nourishments toward the Test and Reference areas could be identified. The influence of the nourishments, the PEMs, and the natural variability were difficult to distinguish at the Test and Reference areas. Therefore, the morphological development of the Test area relative to that of the Reference area was adopted as the primary evaluation criteria. Interestingly, the installation period (2007–2010) exhibited statistically significant different CSIs (coastal state indicators) compared with the 4years prior to installation (2003–2006) for both the Test and the Reference areas. Because both the Test and the Reference areas exhibited very similar behavior prior, during and after the PEM installation period, the analysis was unable to identify the impact of the PEMs. No influence of the PEMs on the local beach and dune morphology could be established. Considering the above and given the fact that the PEM system was also not able to induce a measurable accretion at a similar experiment in Denmark we consider it unlikely any efficacy of the PEM system will be identified in future experiments.

Combined reticular blind drainage and vertical hierarchical drainage system for landfills located in areas with high rainfall and high groundwater level

A novel water control technology that combines the features of a reticular blind drainage system and a vertical hierarchical drainage system is developed and applied in the Yanziyan Sanitary Landfill, which is located at an area (Loudi City, Hunan Province, China) with high rainfall and high groundwater level. The reticular blind drain system, which was installed on the bottom and side walls of the landfill site, can conveniently guide the flow of groundwater out of the site while preventing a disorganized flow of groundwater. The vertical hierarchical drainage system was installed to separate rainfall water and leachate in the landfill site, thus efficiently reducing the pressure of leachate treatment. The whole drainage system plays a key role in foundation stabilization by seepage control and separation and in the instant drainage of rainfall water. The leachate reduction efficiency of the drainage technology was calculated in terms of leachate production before (336519 m3) and after (29664 m3) technology application. Over 90% of leachate derived from rainfall water and groundwater inflow was avoided upon installation of the vertical hierarchical drainage and reticular blind drainage systems. The technology can thus be popularized and applied for water control in landfills located in areas with high rainfall and high groundwater level. The proposed technology can be used to alleviate the pressure of leachate treatment and to reduce the risk of instability.

Experimental Research of Soft Soil Ground Treatment in Yangpu Port by Static-Dynamic Drainage Consolidation

Yangpu Port has inhomogeneous soft soil with the properties of high water content, high void ratio, high compressibility and low shear strength. Based on soft soil ground treatment engineering practice, the geological characteristics are summarized, the ground treatment methods are comparatively analyzed, static-dynamic drainage consolidation method is chosen to treat the soft soil ground, the reinforcing mechanism of vertical and horizontal drainage system are discussed, the design of drainage system, preloading and dynamic consolidation are researched and the surface settlement monitoring, pore water pressure monitoring, side piling displacement monitoring, laboratory soil test and plate loading tests are carried out. The results show that average surface settlement is 1170.8 mm, the physical and mechanical properties of soft soil are improved and the characteristic value of foundation bearing capacity is greater than 120kPa.

Quantifying aquifer water balance and salinity dynamics to minimise environmental impacts of a land‐based effluent treatment system in China

AbstractThis paper presents a groundwater modelling framework to assess the hydraulic loading and salinity impacts on the underlying groundwater system of a large‐scale land‐based effluent treatment system for treating urban sewage of Yanggao County in the north of Shanxi Province, China. This land‐based treatment system is called “Filtration and Irrigated cropping for Land Treatment and Effluent Reuse” abbreviated as FILTER. The FILTER operations include intensive irrigation of crops with urban effluent, filtration through the soil matrix, and pumping and reuse of improved quality drainage water. Three sizes of FILTER were simulated using groundwater modelling techniques to (i) upscale the operations and benefits of an experimental FILTER site to a larger FILTER system to handle the larger volume of effluent and to (ii) assess the potential effects on the regional groundwater. The boundary flux analysis carried out to quantify the net impact of FILTER on the surrounding areas indicated that a well‐designed and managed vertical drainage system can be used in a catchment‐scale FILTER system for productive and environmentally friendly management of domestic wastewater in peri‐urban areas. Results of this innovative and cost‐effective technology from the field trials in Australia and China are promising for wider applications. Copyright © 2009 John Wiley & Sons, Ltd.

Soft ground improvement with solar-powered drainage

In this study, raising the temperature of soft Bangkok clay up to 90°C using solar-powered prefabricated vertical drains during a preloading process was investigated in full-scale field tests. Two identical 6 m high, full-scale test embankments for preloading were constructed over the soft Bangkok clay where a conventional vertical drainage system was installed underneath one embankment and a solar-powered system was utilised for the other. Analyses were carried out to determine the flow parameters by back-calculation of field settlements in terms of the horizontal coefficient of consolidation (Ch) and the ratio between the horizontal hydraulic conductivity in the undisturbed zone (Kh) to the horizontal hydraulic conductivity in the smear zone (Ks). The field test analysis based upon the back-calculated results shows that the Kh/Ks values were 6·2 and 4·1 for drainage without and with heat, respectively, with corresponding Ch values of 6·8 and 8·5 m2/year, respectively. Thus, the use of solar heating can increase the drainage performance by reducing the drainage retardation effects in the smear zone around the drain.

An empirical approach to determine peak air pressure within the 2‐pipe vertical drainage stack

Following the massive outbreak of SARS (Severe Acute Respiratory Syndrome) in early 2003, the drainage systems in high‐rise residential buildings have become a major concern. Inappropriate drainage system design may cause pressure fluctuations and depletion of the water trap seal. In Taiwan, most vertical drainage stack pipes serving medium‐height apartment blocks are designed as 2 or more vertical pipe systems. A prediction method to determine the air pressure distribution within the single‐stack vertical drainage system with a single discharge has already been established. This paper expands this prediction method to allow the air pressure distribution of the 2‐pipe vertical drainage and vent system, which is widely used in Taiwan, to be predicted. Comparisons between the measured data and calculated values reveal that the prediction method can reproduce the negative and positive peak air pressure values within the 2‐pipe vertical drainage stack given single point discharge and steady flow conditions. A prediction model based on empirical parameters offers a reference for drainage system designers designing and maintaining water trap functions in buildings. This prediction method can be easily applied to drainage system design.