Installation Of Drains Research Articles

Fully hydro-mechanical coupled analyses of the deep excavation above a multi-aquifer-aquitard system

Deep work shaft excavations have become increasingly common as a preliminary step of tunnel construction. Deep excavation above a multi-aquifer-aquitard system (MAAS) complicates the flow field and stress field surrounding the excavation, inevitably affecting the performance of excavations. However, previous studies with drained or undrained analyses ignored the effects of dewatering-induced groundwater flow on the performance of deep excavations. To better understand this aspect, this study performs fully hydro-mechanical coupled analyses to investigate the performance of a 39.5 m-deep excavation above a multi-aquifer-aquitard system, which considers dewatering in two confined aquifers. A sophisticated three-dimensional (3D) numerical model is developed to simulate the detailed construction processes of drainage, excavation, dewatering, and strut installation. The study presents a comparison of two scenarios (with and without dewatering in a confined aquifer) with respect to wall deflection, stratum deformation, pore pressure, and effective stress path. The analysis results indicate that the effective stress paths are highly dependent on stratum permeability and construction activities. The dewatering behavior significantly reduces the excavation-induced deformation, primarily due to increased effective level and consequently increased resistance on the excavated side. As a result, ground settlements decrease due to less wall deflection.

A comparison of subperiosteal vs subdural drainage in the treatment of chronic subdural haemorrhage

Introduction. Symptomatic chronic subdural haemorrhages (CSDH) continue to be one of the most common diagnoses in modern neurosurgery. The current standard procedure for symptomatic CSDH is a burr-hole craniostomy with irrigation and the installation of close-system drainage. The purpose of this study is to conduct a direct comparison of two surgical procedures for the treatment of symptomatic CSDH that are effective in prior studies. Our main goal was to compare the efficacy of placing a subperiosteal drain (SPD) and a subdural drain (SDD) after a single burr-hole craniostomy and irrigation and to show any significant differences in terms of overall surgical complications, functional outcome and mortality rate at three months, and complications at six months. Materials and methods. From August 2022 to December 2023, the study was conducted in the Department of Neurosurgery at a tertiary care centre, with a total of 25 patients in both treatment groups. Results. Overall, there was no statistically significant difference between the two groups in terms of patient general characteristics, pre-and post-operative symptoms, Markwalder grades, postoperative hematoma volume and recurrence, mortality, and functional outcome at discharge and at three months follow-up. Despite not reaching statistical significance, we found a decreased risk of surgical complications, particularly post-operative cerebral haemorrhage, with SPD system implementation. Conclusions. According to our findings, both therapy modalities are extremely successful in the treatment of CSDH. therapy with a single burr-hole craniostomy, irrigation, and implantation of the SPD system, on the other hand, has a reduced overall surgical complication rate and can be regarded as a therapy of choice for the management of symptomatic CSDH.

Improvement of laparoscopic interventions on the bile ducts in choledocholithiasis

Objective. To improve the technique of laparoscopic choledocholithotomy to improve the results of choledocholithiasis treatment. Materials and methods. The study covers the period from 2012 to 2022, during which 144 patients with choledocholithiasis were treated. In 120 patients, the surgical intervention was successfully performed using a fully laparoscopic approach: in 48 patients (group 1), the common bile duct was drained with a T-shaped drainage; in 34 patients (group 2), the intervention on the common bile duct was completed with a primary suture of the duct; in 38 patients (group 3), a biliary stent was inserted integrally with subsequent suturing of the choledochotomy opening. Results. In group 1, 5 (10.4%) patients had serious complications that required repeated surgical interventions: dislocation of the T-shaped drainage in 1 (2.1%) patient, development of biliary peritonitis in 4 (8.3%) patients. In the treatment of patients in group 2, a number of advantages were noted compared to the treatment of patients with T-shaped drains. The majority of patients with primary common bile duct suture were discharged on the 3rd day after surgery, and they returned to active work in 2 to 3 weeks. At the same time, 3 (8.8%) patients in this group had complications that required repeated surgical interventions: in 1 patient with multiple choledocholithiasis, bile leakage into the abdominal cavity was caused by a residual stone, in 2 patients - by papillitis and partial inflammatory stenosis of the large duodenal papilla. They underwent endoscopic papillotomy. Of the 38 patients in group 3, 32 had biliary stents that migrated to the intestine on their own. These patients had no complaints in the long term. In 6 patients, the stents remained in the ducts for 30 days after surgery. In 5 of them, endoscopic dosed papillotomy with a needle papillotome was performed, after which the stents were easily removed from the ducts. In 1 patient, a stone up to 6 mm in diameter fell out of the common bile duct along with the stent. None of the patients had signs of pancreatitis or elevated blood amylase levels. Conclusions. Laparoscopic interventions on the common bile duct allow successful removal of large and numerous calculi in one stage. Primary suturing of the common bile duct has significant advantages over the installation of T-shaped drains and allows to reduce the treatment time. In case of multiple choledocholithiasis and suspected stenosis of the duodenal papilla, it is advisable to combine primary common bile duct suture with antegrade stenting of the bile ducts.

Study comparison of ground subsidence due to preloading installation of egg tray triangular vertical drains with distance variations on a small laboratory scale

Abstract The approach to infrastructure development is conducted on soft clay soil, which introduces the threat of consolidation-induced subsidence. The construction soil must possess adequate bearing capacity and shear strength to withstand the loads imposed on it throughout the construction process. Soil with low shear strength necessitates reinforcement to enhance its bearing capacity. This study aims to investigate the effects of preloading on the settlement behavior of soft soil. Applying clay-filled test containers, the laboratory implements the method through a small-scale model approach. As preloading, an embankment load is applied to the soil. The supplementary weight was incrementally increased by 1 kg, 2 kg, 4 kg, 8 kg, and 16 kg for five days. The sample experiments that were conducted were EgVD-0, EgVD S-17, and EgVd S-29. Consolidation was observed in the outcomes of the EgVD S-17 and EgVD s-29 investigations, surpassing EgVD-0 by 53.69% and 57.19%, respectively. EgVD S-17 of 3.56 cm and EgVD S-29 of 3.92 cm were present along with an EgVD-0 decrease of 1.65 cm.

The effects of improved subsurface drainage on runoff and nitrogen leaching from a clayey field section

AbstractThe aim of this study was to investigate the effects of improved subsurface drainage installation on nitrogen (N) loss in drain discharge (DD) and topsoil layer runoff (TLR). Data on DD and TLR, as well as on concentrations of total, nitrate and ammonium N in the runoff components, were collected from four sections of an experimental field in southern Finland (June 2007–December 2018). Supplementary drains were installed in one of the field sections in June 2014, and the data from that section were compared with those from three reference sections. Differences between the sections were statistically analysed based on annual and monthly values of runoff components and concentrations, as well as the loads of N fractions. The results revealed that improved drainage increased the N load in the DD, reducing the load in the TLR. Changes in N loads were more clearly driven by changes in the runoff volumes rather than by changes in the N concentrations in the runoff waters. Before the drainage improvement, most of the total N load was nitrate (53%), while the share of rest N (fraction of the total N after the mineral N fractions were subtracted) was 45%. After improved drainage, the percentages of nitrate and rest N were 73 and 26%, respectively. The results demonstrate the importance of agricultural water management as the key driver for controlling nutrient loads.

Development of a finite element groundwater flow model to test drainage management strategies for the expansion of the Dareh-Zar open pit mine, Iran

A finite-element groundwater flow model was developed for the expanding Dareh-Zar open pit mine in southern Iran, to simulate groundwater inflow into the excavation and mine wall pore pressure dynamics. The model was used to test the effectiveness of implementing different drainage management strategies to reduce groundwater inflow rates and mine wall pore pressures, including abstraction wells and horizontal drains. Model predictions suggest the implementation of abstraction wells will reduce groundwater inflow rates by 75% during the first 12 years of mining and 50% during the subsequent 5 years relative to a ‘no drainage’ management scenario, with further reductions in groundwater inflow achieved through horizontal drain installation. Furthermore, the installation of horizontal drains was found to be necessary to reduce mine-wall pore pressures from destabilizing the mine walls. Groundwater management of the decommissioned pit mine was also evaluated, with simulation results suggesting that backfilling the excavation would restore the groundwater level within the open pit mine region to ~2,442 m above sea level, representing a net restoration of ~204 m relative to the water table prior to mine closure.

Soil carbon dynamics in drained prairie pothole wetlands

Drainage leads to trade-offs between crop production efficiency and wetland conservation, with complex impacts on ecosystem services. In North America’s Prairie Pothole Region, wetland drainage is widespread, often to increase the available land for cultivation, prevent crop loss due to flooding, and manage soil salinity. Wetlands are known for providing key ecosystem services such as improved water quality, flood mitigation, and carbon storage. There is limited research on how changes to soil hydrology and soil redistribution through wetland drainage can impact soil carbon storage and persistence in this region. This research evaluates factors that contribute to soil carbon storage in drained prairie pothole wetland based on 33 drained wetlands in Saskatchewan, Canada. These analyses showed regional differences in the response of soil carbon storage to drainage that are driven by environmental factors such as annual precipitation, temperature, and wetland permanence. We observed increasing soil carbon storage from the Dark Brown to Black soil zones, as well as with longer wetland pond permanence. The sampling depth used for calculating soil carbon storage was especially important when comparing geographically across the soil zones as the Black soil zone had greater soil carbon stored at depth. Soil carbon was also intensively monitored over 2 years following installation of surface drainage across a wetland complex (8 drained wetlands) where water was partially directed to a consolidation wetland. We further assessed changes in soil carbon dynamics and protection from microbial decomposition based on three soil organic matter fractions, ATR-FTIR for organic matter functional groups, and phospholipid fatty acid analysis to understand the microbial community abundance and structure. After 2 years following drainage, ephemeral wetlands with short pond permanence were found to be most sensitive to drainage and the only wetland class with decreases in soil carbon. The temporary and seasonal wetland classes showed no significant differences in soil carbon content but there were changes in the organic matter with depth due to soil redistribution during drainage implementation. Jointly, this research provides region-specific estimates of soil carbon storage in drained prairie pothole wetlands that can be used to inform wetland soil carbon management in cultivated fields.

Drainage of irrigated agriculture in Bihar, India—Some issues

AbstractIrrigation development has been taking place for centuries in India. Considerable areas of fertile land under irrigated agriculture have gone out of production due to waterlogging and salt‐related problems. The provision of drains was deferred or postponed in several projects due to shortage of funds during the initial stages. Because of this fact, the productivity of water (t ha⁻¹ mm⁻¹) in India still remains very low. The main reason for the low yields is improper water management, especially lack of drainage in irrigated command areas. There are vast areas in the country urgently requiring drainage works and the present governmental resources are not adequate to cope with the growing demand. Promotion of the private sector in reclamation work and installation of subsurface drains at local level needs encouragement. All these issues together with the research activities inclusive of drainage materials undertaken by different organizations are critically described and discussed in this paper.

Stabilization of Shallow Landslides Induced by Rainwater Infiltration—A Case Study from Northern Croatia

Climate change brings with it phenomena such as large amounts of rainfall in short periods. Infiltration of rainwater into clayey soils is a common trigger for shallow landslides on slopes. In this way, numerous shallow landslides occur in the area of northern Croatia, and a characteristic example is the landslide “Orehovčak”. To stop the sliding of the destabilized slope, it was necessary to solve the drainage of water that infiltrates the landslide body. For this purpose, detailed geotechnical investigations and monitoring were conducted. Many data were collected at the investigation site, especially soil characteristics and groundwater fluctuations. The surface soil on the slope consists of highly plastic clay, and the sliding surface was created in contact with the solid subsoil of marl, the depth of which varies positionally. The analyses confirmed that water is a slip trigger. To solve the problem, excavations and installation of deep drains were performed. The slope safety factor confirms landslide stabilization, whose calculated value after rehabilitation was Fs = 1.645. Inclinometer readings carried out after remediation show that slope slippage stopped. This confirms that the presented remediation method is very applicable to shallow landslides in northern Croatia and similar landslides around the world.

Evaluating Transient Drawdown and Slope Stabilization from Horizontal Drain Installation

Elevated groundwater levels drive slope instability through decreased effective stresses and frictional strength. Consequently, landslide mitigation often relies on a variety of stabilizing techniques, often including dewatering and drainage as a primary control on stability. One of the most effective dewatering techniques for landslides are horizontal drain systems, which consist of arrays of perforated pipes drilled into hillslopes for gravity-driven removal of groundwater. One of the few economical solutions for large-magnitude, groundwater-driven landslides, horizontal drain arrays facilitate groundwater drawdown through gravity-driven flow, consequently increasing effective stress and slope stability within its domain of influence. However, design of horizontal drain systems remain largely observational and there is limited insight towards the transient performance of these drainage systems. This study aims to explore relevant theoretical design criteria for horizontal drain systems and their relative importance as related to drawdown mechanism and magnitude, as well as slope stability.

SURGICAL TREATMENT RESULTS OF PATIENTS WITH PHLEGMONS OF THE NECK USING A PORTABLE SYSTEM FOR TREATING WOUNDS UNDER NEGATIVE PRESSURE

Abstract. The failure of high e ffi ciency of treatment of phlegmons in the deep tissue spaces of the head and neck is to some extent explained by the rapid and sometimes fulminant complications development of that threaten the patient’s life, such as thrombosis of the neck veins, sepsis, erosive bleeding, mediastinitis, and others.Research objective: to study the eff ectiveness of portable systems using for the treatment of wounds under negative pressure in the postoperative period in patients with phlegmons of the neck.Material and methods. The results of the treatment of 54 patients undergoing treatment for deep phlegmons of the neck were analyzed.All patients were divided into two groups. The main group included 30 patients with intraoperative installation of a portable system for the treatment of wounds under negative pressure.The comparison group consisted of 24 patients with the classic installation of glove-tube drains in the anatomical locations indicated below.Research results. In all 54 patients, collar Razumovsky V. I. mediastinotomy was applied. The transition to serous discharge from the wound occurred in both groups: in the comparison group, on average, 267.4 hours after the end of surgery, while in the main group, on average, 38.9 hours after the end of surgery. On the 15th postoperative day, an average of 3.6 ml per group – in the main group, 58.7 ml – in the comparison group.In the postoperative period, 4 (7.4 %) patients developed purulent mediastinitis: 1 (3.3 %) patient from the main group, and 3 (12.5 %) patients from the comparison group. All patients underwent identical intensive treatment measures. Two of these patients from the comparison group died due to the development of acute cardiovascular insu ffi ciency, which made the total mortality for the group, respectively, 2.2 %. There were no fatal consequences in the main group. It should be noted that the average length of hospital stay in the main group was 14 days (336.1 hours), while in the comparison group, it was 27 (657.8 hours) days.In the postoperative period, 3 (13.64 %) patients of the comparison group had cicatricial stenosis of the esophageal anastomosis, in connection with which one of them had an esophageal stent installed, and the other two underwent courses of dilation procedures.Conclusions. In general, in the main group, the use of a mobile portable system for the treatment of wounds under negative pressure refl ects a signifi cantly more favorable postoperative course in patients of the main group and contributes to the prevention of infectious complications after surgical interventions and wounds, improves the drainage process by eff ectively emptying wounds and cavities from the accumulated exudate and allows signifi cantly improve the results of surgical treatment of deep phlegmons of the neck.

Use of navigation technologies in the installation of external ventricular drainage in patients with severe combined traumatic brain injury

The study investigated the possibilities and effectiveness of surgical navigation in the installation of external ventricular drainage in patients with severe combined traumatic brain injury. In total, 41 patients were examined, and in those with urgent indications during the first period of traumatic illness, external ventricular drainage was installed (up to 2 days). All patients were divided into the main group (n = 14) and control group (n = 27). In the main group, external ventricular drainage was installed using surgical navigation. The control group underwent surgery without surgical navigation. According to the treatment results of the main group, the use of surgical navigation during the introduction of ventricular drainage significantly increased the accuracy of its installation and reduced the number of complications and rechecks. The accuracy of ventricular drainage installation was improved by 35%. Thus, out of 13 drainage installations, 12 (92.3%) had an optimal position, and 1 had a satisfactory position because its tip had a deviation of 2 mm; however, this drainage did not require re-examination, performing its function. Moreover, in the control group using the classical free hand technique, out of 21 cases with drainage installed, only 12 (57.1%) had an optimal position, 9 (42.9%) drains were rechecked because of deviation from the specified trajectory over 3 mm, and 4 (19%) required repeated rechecking (p = 0.039). The main causes of errors and complications of the surgical treatment of patients with craniocerebral injuries are related to the difficulties in installing ventricular drainage, namely, inaccurate positioning of the drainage tip, placement of the drainage in the brain substance at a distance from the planned point (28.6%), the drainage is going beyond the ventricular system of the brain (14.3%), re-drainage during the operation (44.4%), which often (42.9%) leads to incorrect introduction of the drainage into the ventricular system of the brain. Thus, the application of the navigation technology technique when installing drains into the ventricular system of the brain is very effective in the treatment of patients with severe combined traumatic brain injury. This innovative technique for ventricular drainage in severe combined traumatic brain injury will reduce the frequency of errors and complications associated with repeated drains, which is fundamentally important in unstable patients with multiple traumas. The navigation system allows for accurate installation of the drainage to the planned location from the first attempt.

Перкутанная нефролитотрипсия у детей с использованием инструментария миниатюрного размера.

Introduction. Currently, percutaneous nephrolithotripsy is the main treatment for large and coral-like kidney stones in children. The purpose of the study was to increase the effectiveness of percutaneous nephrolithotripsy (PCNL) in children using miniature-sized instruments. Materials and methods. For the period from 2008 to 2019, 320 children aged 1 to 17 years underwent nephrolithotripsy in the pediatric department of the N. Lopatkin Scientific Research Institute of Urology. Depending on the size of the instruments used, patients were divided into 3 groups. The first group included children who underwent surgery using the Mini-PCNL technique (n-211), the second group included patients operated on using the Ultra-Mini-PCNL method (n-16) and the third group included children whose percutaneous intervention was performed using a standard-sized nephroscope (n-93). The intervention was carried out according to the standard method; all patients underwent cystoscopy, catheterization of the ureter, access formation, lithotripsy, lithoextraction and installation of nephrostomy drainage. Results. In the first group of children studied, complete elimination of clinically significant stones (residual stones smaller than 4 mm) after the initial intervention was achieved in 169 (80.1%) pediatric patients. In the second group, there was 13 (81.2%) children. And in the third group, getting rid of stones was achieved in 73 (78.5%) patients. The average time required to perform surgery in all three study groups was comparable and amounted to 45 (40-125) minutes in the first group, 40 (25-85) minutes in the second, and 50 (40-180) minutes in the third group. The final efficacy of percutaneous nephrolithotripsy in children using instruments of various sizes in the first group was 89.6%, in the second – 93.7% and 88.1% in the third study group. The hospital stay after surgical treatment was: 4 (3-12) days for the first group, 3.5 (3-7) and 4.5 (3-17) days for the second and third groups, respectively. The need for additional interventions after PCNL in pediatric patients was in 69 (32.7%) children in the first group, 4 (25%) in the second and 41 (44.1%) in the third group. Conclusion. The use of mini-PCNL, ultra-mini-PCNL can reduce the duration of surgical intervention by 10% and 20%, the hospital stay after PCNL by 11.2% and 22.3%, the need for additional interventions by 11.4% and 19.1%. Can reduce the total number of complications by 10% and 12.2%, respectively, compared with the use of standard-size instruments. The use of Mini-PCNL in children is indicated in the younger and middle age groups, Ultra-Mini-PCNL is indicated for single stones up to 2 cm or as an additional access in the multi-accesses formation.

Implementing Vertical Drainage to Reduce Flood Risk at Settlement Area in Medan


 With the increasing number of residents in a city, there will be excessive exploitation of nature, uncontrolled land use changes and a decrease in the carrying capacity of the environment. These various results have a potential to increase the frequency and severity of flood disasters. Flooding is a problem for the town because it leads in losses of property and lives, the emergence of health issues, damage to different infrastructure facilities and infrastructure, among other things. Although the government has been developing a horizontal drainage system for years, it has yet to decrease urban flooding. Consequently, a new technique is required to overcome flooding, specifically the use of vertical drainage. In an attempt to improve the community's living conditions, this activity's goal is to reduce the risk of flooding in Kelurahan Pasar Merah Timur settlement area. The advantages of this program include an improvement in the community's quality of life as a result of less intense flooding following the installation of vertical drainage. According to the test, 2 liters of water can be drained into the aquifer channel every second by the vertical drainage. So it can be assumed that if there is a puddle of water that cannot be drained by horizontal drainage of 4000 liters or 4 m3, it will take 34 minutes to deliver the water into the aquifer layer.

An analytical solution for nonlinear consolidation of composite foundations improved by stone columns and vertical drains

The nonlinear compressibility and permeability of soft soils is a key factor in the consolidation of both composite and natural foundations. However, there are few corresponding consolidation theories for vertical drain-stone column composite foundations in which the nonlinear consolidation characteristics of soils can be taken into account. In this study, a nonlinear consolidation model is established to describe the seepage relations between soft soils, vertical drains and stone columns. Then, a consolidation governing equation is derived, where the total excess pore water pressure (EPWP), u¯, is a variable, and the average consolidation degree defined by strain and stress of the composite foundation is obtained, respectively. Numerous calculations are performed to analyze the consolidation behaviors of such composite foundations. The results show that the installation of vertical drains can enhance the consolidation rate effectively; the external load and the initial modulus ratio of column to soil have an influence on the stress concentration effect of stone columns. Finally, the proposed analytical solution is applied to the settlement calculation for an actual project, and the calculated results are in good agreement with the measured data in the early and late stages of consolidation.

Evolution of pH, redox potential and solute concentrations in soil and drainage water at a cultivated acid sulfate soil profile

Land drainage lowers the soil water table, which triggers enhanced oxidation of iron sulfide minerals in acid sulfate soils, causing acidification of fields and posing environmental hazards to aquatic ecosystems. The objective of this study was to develop a model for investigating the effects of oxidation of iron sulfide minerals and the cation exchange capacity (CEC) on the long-term evolution of pH, redox potential and solute concentrations in soil water and drain discharge. Two electron acceptors (oxygen and ferric iron) were included in the model. The model was implemented in the HP1 modeling platform (coupled HYDRUS-1D and PHREEQC-3) and applied to an acid sulfate soil profile of an agricultural field in Finland. The geochemical part of the model was tested against field observations. A comparison of different model versions showed that CEC had an essential role in mimicking the observed pH profile of soil. The drain discharge water quality was similar in the model versions both with and without CEC, but the buffering effect of CEC could be seen as lower iron concentrations. The oxidation of metastable iron sulfide minerals was three times faster than the oxidation of pyrite. Descriptions for the oxidation of both two minerals and for CEC were required to conduct long-term simulations that reproduce the observed geochemical state of a drained agricultural field. The HP1 modeling platform facilitated the testing of alternative chemical transformation processes of an AS soil profile in response to increased drainage efficiency after subsurface drainage installation.

Обоснование списочного парка насосов и трубопроводных ставов рудничной водоотливной установки

The complex of drainage system of an underground mining enterprise ensures the safety and continuity of mining operations. Deterioration of the level of reliability of the functioning of the mine drainage system can lead to the following serious consequences. The main link of the mine drainage system is a drainage system equipped with pumping units based on the centrifugal pumps. One of the main criteria for the safe operation of a mine drainage system is its equipment with a sufficient number of pumping units. An assessment of the efficiency of the classical methodology for calculating the listed park of pumping units is given, including consideration of the amendment made to it regarding the given water inflow regime. The main drainage installation of the Udachny underground mine, equipped with sectional pumps, was chosen as the object of research. It is established that the list park of pumping units calculated according to the known methods does not allow to ensure a high level of reliability of the operation of the drainage plant. The same picture is typical for the park of discharge pipe sections of the drainage plant. When calculating the list park of pumping units of a drainage system, it is more expedient to consider not the passport performance of the pump, but its average value between major repairs. The number of pumps under repair depends on the average duration of repair work and the average time between failures of the pump. A method is proposed for calculating the optimal number of pumping units and pipe sections of a drainage system from the point of view of ensuring its reliable level of functioning. The results of the performed research will be useful to the specialists responsible for the design of drainage systems for underground mines and coal mines in the Russian Federation.

Improved Mandrel System for Prefabricated Vertical Drain Installation: A Macro to Micro Analysis

Increasing development of infrastructure in Indonesia has driven the need for effective ground improvement methods to accelerate the consolidation of soft soil, which is estimated to occupy around 10% of the country’s land area. A prefabricated vertical drain combined with vacuum preloading is among the most effective methods for this purpose. However, the prefabricated vertical drain creates a smear zone in the surrounding soil area during installation. This study examines the effectiveness of a newly developed mandrel system in reducing the smear zone during prefabricated vertical drain installation. Large-scale consolidation tests at a macro level and microstructure analysis using scanning electron microscopy at a micro level were employed to investigate the effect of soil water content and shear strength. The results show that the water content and shear strength of the soft soil gradually increased in the inner smear zone and transition zone, while both decreased in the radial distance. Furthermore, the soil structure underwent a transformation in which the particle area and pore area became a closed flake structure, and apparent agglomeration occurred. The test results indicate that the newly developed mandrel system can effectively reduce the smear zone. The macro to micro test results demonstrated that the mandrel system is successful in reducing the smear zone effect.

Development of a software tool for economic evaluation of health, safety, and environmental initiatives in a combined cycle power plant

Background: This study aimed to provide a comprehensive tool for the economic evaluation of investments in health, safety, and environment (HSE). Methods: This developmental cross-sectional study was conducted on the costs and benefits of HSE investments in a combined cycle power plant in Gilan province, 2021. The components of preventive measure costs (PMCs) and occupational accidents, diseases, and environmental pollution costs (ADPCs) were determined by an expert panel and review of scientific literature. The HSE economic assessment tool (HSE-EAT) was developed in Microsoft Excel software using macro/visual basic coding. The tool was designed to determine the efficient measures using the cost-benefit analysis (CBA) and the combination of control measures with the highest financial benefits using the cost-effectiveness analysis (CEA). Results: The application of the HSE-EAT in a combined cycle power plant showed the highest return on investment (ROI) for installation of drains for ducts of diesel fuel pipes and the lowest ROI value for renovation of emergency eyewash and shower. The ratio of indirect to direct benefits of implementing the preventive measures in the worst-case and best-case scenarios were 3.0 and 1.3, respectively. Conclusion: The HSE-EAT exhibited the advantages of comprehensiveness, flexibility, being user-friendly, and faster and more accurate calculations and could be also used for economic evaluation of health, safety and environmental initiatives in other industries and organizations.

Developing Systems-Level Criteria for Evaluating Performance of Horizontal Drains toward Landslide Mitigation: Case Study of the US20 Pioneer Mountain-Eddyville Realignment Project

Opened to traffic in 2016, the Pioneer Mountain-Eddyville (PME) realignment was a major highway infrastructure project that began in 2005 and created approximately 9 km of new highway on US Route 20 in the Oregon Coast Range. Due to the renewed activity of a series of paleolandslides that traversed the project right-of-way, deliver of the construction project was significantly delayed. Owing to the size and activity of these slope failures, a large monitoring network of piezometers and other instrumentation was deployed as a precursor to the installation of an extensive system of horizontal drain arrays (176 km of drain length) intended as one means of landslide mitigation through control of in situ groundwater. Because there is limited guidance regarding monitoring the long-term performance or design life of horizontal drains, hydrological data in drained areas were monitored as a means of observing performance during and after project completion. This case study describes observations of groundwater behavior prior to—and after—drain installation, thereafter proposing site planning–level metrics for evaluating the continued function of horizontal drain systems. Drain function is considered through groundwater response to precipitation, but also through a simple evaluation of water storage in the catchment of each landslide. The four paleolandslides—Cougar Creek, Crystal Creek, Eddy A/B, and Eddy C/D—demonstrate different responses to drain installation and long-term performance. Using simple metrics based on monitoring, added indices for evaluating long-term horizontal drain performance at the site scale are proposed. Consistent with the Observational Method, these criteria may serve as additional guidance for a monitoring-based framework for evaluating the life cycle of horizontal drains as a landslide mitigation system and a basis for planning drain maintenance or added mitigation measures.