Tardigrades Research Articles

Three‐Dimensional Simulation of Shoaling Internal Solitary Waves and Their Influence on Particle Transport in the Southern Red Sea

AbstractThe shoaling process of a group of internal solitary waves (ISWs) in the southern Red Sea is simulated with a three dimensional, nonhydrostatic, high‐resolution MIT general circulation model. The breaking and dissipation processes are well reproduced, in which a positive tail forms behind and locally moves the interface upward, causing the transformation of wave polarity as it moves onshore. With the step‐like structure followed, the wave eventually evolves into smaller water bores. Combined with the parameters of the leading wave slope (Sw) of about 0.07 and topography slope (S) of about 0.01, the shoaling is suggested to follow a mild breaking process. The particle transport during the shoaling process is further examined quantitatively using the Connectivity modeling system (CMS). About 38,400 particles are released at six different vertical layers in the main shoaling domain. Most of the particles are transported up‐and‐down following the wave oscillation process then settle within 10–20 m around the original released depth. For the particles inside the breaking area, the oscillation process becomes more complex and intensified, and eventually a great portion of these particles settle far away from their released locations. The time‐integrated transport distance, Ti, and the direct transport distance, Ts, are also analyzed. With Ti almost 20 times to Ts in vertical, continuous up‐and‐down movements are suggested during the shoaling process.

CONTAMINATION ASSESSMENT OF WATER RESOURCES AROUND WASTE DUMPSITES IN ABAKALIKI, NIGERIA; A MINI REVIEW

Monitoring of water quality is needed from time to time to avoid outbreak of severe water borne disease. This article review previous literature on impact of waste dumpsites on water quality around Abakaliki and its environs, with emphasis on active and non-active dumpsite. Findings from reviewed article revealed that waste dumpsite sites close to water bodies or ways has altered water quality in Abakaliki urban, while groundwater is contaminated through leaching process. This groundwater contamination occurs mostly when waste dumpsite is sited close to borehole or hand-dug well. Based on reviewed literature it is advised that waste dumpsite should be sited distance away from residential buildings as the state government should also endeavor to continually monitor water quality for domestic use to avoid outbreak of various kind of water related disease.

Pola Spasial Daya Dukung Sumber Daya Air Di Kecamatan Driyorejo Kabupaten Gresik

The Regional Disaster Management Agency (BPBD) of Gresik Regency in 2019 stated that some villages in the Driyorejo District, Gresik Regency experienced drought, this condition is in contrast to the availability of water in 2012. The purpose of this study is to determine the spatial pattern of the carrying capacity of water resources. and direction of control policies for the carrying capacity of water resources. The research method used quantitative and qualitative descriptive analysis with the analysis technique of Water Bearing Capacity (DDA), Analytical Hierarchy Process (AHP) and spatial analysis using Arcgis 10.1 Software. Data collection techniques in the form of observation, documentation, questionnaires and agency surveys. The results showed that the water carrying capacity in Driyorejo District was 99.7% surplus and 0.3% deficit. The status of deficit water carrying capacity is in Petiken and Mojosarirejo Villages, especially in the industrial and service trade sectors. The main priority for the direction of the water carrying capacity control policy based on AHP is to improve land rehabilitation, development of infrastructure and improve the quality and quantity of water sources with scores of 161.4, 98 and 40.6, respectively.

Fabrication of graphene oxide microcapsules based on Pickering emulsions for self-healing water-borne epoxy resin coatings

Metallic iron oxide nanoparticle-modified graphene oxide (GO) sheets were well applied for stabilizing oil-in-water (O/W) Pickering emulsion, because they were easy to fabricate via a redox reaction between metal salt and GO nanosheets. A systematical investigation was conducted on the impacts of metal salt concentration for preparing the nanoparticle-modified GO, GO aqueous dispersion concentrations and the mass ratios of GO/oil phase on the characteristics of Pickering emulsion. As revealed from the outcomes, the graphene oxide encapsulated GMA microcapsules (GMA@GOMCs) exhibited high loading capacity and thin shell thickness. Then, the microcapsules were embedded into water borne epoxy matrix and fabricated the coating which were capable of healing themselves over surface of hot-dip galvanized steels, as only supplementing a less amounts of microcapsules might achieve almost repaired completely. It’s expected that the GOMCs based on Pickering emulsions can be applicable in a wide range of applications, such as automotive field, weather and marine environments.

Assessment of Physicochemical and Bacteriological Quality of Well Water Samples in Ido Community, Nigeria

This study was carried out to investigate the physicochemical and bacteriological quality of well water samples in Ido community. Thirty water samples were collected from five different wells ( six samples from each well) and subjected to standard microbiological and physicochemical analysis. All physicochemical properties showed difference (p<0.05) in all the wells analyzed except temperature and turbidity. Temperature ranged between 25.3±3.50C and 26±2.350C; pH, 6.3±0.7 and 6.9±0.3; electrical conductivity, 127.6±1.9 and 157.8±7.7μs/cm; total suspended solids, 25.2±8.9 and 53.2±1.8mg/l; turbidity, 0.15±0.7 and 1.20±1.4NTU; dissolved oxygen, 4.40±2.8 and 5.35±2.1 mg/l; Biological Oxygen Demand, 9.40±2.8 and15.4±2.8mg/l; Chemical Oxygen Demand, 177.2±1.6 and 260.3±1.6mg/l; chloride, 59.8±8.5 and 101.2±2.6mg/l and total hardness, 246.6±1.9 and 395.6±2.7mg/l. All values fell within WHO standards except Chemical Oxygen Demand (WHO Standard 40mg/l) and total hardness (WHO Standard 100mg/l). Results of microbial population did not show any difference (p>0.05) across the wells. However, Total Heterotrophic Bacteria ranged from 2.15±0.91×104 to 5.3±0.86×104cfu/ml; total coliform, 3.00±0.77×104 to 6.18±0.73×104 cfu/ml; Total feacal coliform, 2.61±0.71×104 to 4.39±0.76×104 cfu/ml; Total vibrio count, 2.68±0.81× 103 to 4.4±0.86×103 cfu/ml; Total salmonella shigella count. 2.02±0.84×103 to 4.8±0.95×103 cfu/ml. Total coliform bacteria ranged from 220 to > 1600 coliform MPN index /100ml-1, while thermo tolerant coliform bacteria ranged from 220 to 1600 coliform MPN index /100ml-1. A total of forty bacterial isolates belonging to ten genera were identified. They include species of Bacillus 22 (26.4%), Staphylococcus 14(16.8%), Vibrio 13(15.7%), Serratia 6(7.3%), Enterobacter 6(7.3%), Chromobacterium 4(4.8%), Salmonella 4 (4.9%), Shigella 4(4.8%) and E. coli 4(4.8%). This result highlights the fact that well water in Ido community are not safe microbiologically for drinking without additional treatment such as boiling or disinfection and this could lead to outbreak of water borne diseases. Good and proper environmental and personal hygiene is advocate especially by the users of those wells to prevent their contamination with bacterial pathogens.

Covariance distributions in single particle tracking.

Several recent experiments, including our own experiments in the fission yeast, Schizosaccharomyces pombe, have characterized the motions of gene loci within living nuclei by measuring the locus position over time, then proceeding to obtain the statistical properties of this motion. To address the question of whether a population of such single-particle tracks, obtained from many different cells, corresponds to a single mode of diffusion, we derive theoretical equations describing the probability distribution of the displacement covariance, assuming the displacement itself is a zero-mean multivariate Gaussian random variable. We also determine the corresponding theoretical means, variances, and third central moments. Bolstering the theory is good agreement between its predictions and the results obtained for various simulated and measured data sets, including simulated particle trajectories undergoing simple and anomalous diffusion, and the measured trajectories of an optically trapped bead in water, and in a viscoelastic polymer solution. We also show that, for sufficiently long tracks, each covariance distribution in all of these examples is well-described by a skew-normal distribution with mean, variance, and skewness given by the theory. However, for the experimentally measured motion of a gene locus in S. pombe, we find that the first two covariance distributions are wider than predicted, although the third and subsequent covariance distributions are well-described by theory. This observation suggests that the origin of the theory-experiment discrepancy in this case is associated with localization noise, which influences only the first two covariances. Thus, we hypothesized that the discrepancy is caused by locus-to-locus heterogeneity in the localization noise, of independent measurements of the same tagged site. Indeed, simulations implementing heterogeneous localization noise revealed that the excess covariance widths can be largely recreated on the basis of heterogeneous noise. Thus, we conclude that the motion of gene loci in fission yeast is consistent with a single mode of diffusion.

Integration of Magnetic Data and Geo-Spatial Analysis for Characterising Aquiferious Yields in New Estate, Covenant University, Ota, Ogun State

This study was conducted to understand the possible causes of abortive boreholes along the New Estate in Covenant University. The conceptual model predicted the two groundwater characteristics of weathered and the unweathered zones. The V-shape curve revealed two groundwater anomalies with high and low curves. The peak anomaly indicates the higher resistivity, presumed to be the geological structures of unsaturated features in the area. The sink V-shape curve indicate an anomaly with groundwater features, presenting low resistivity values attributed to be water bearing formation that will be viable for groundwater potential. The Iso-resistivity contour map identified possible groundwater features. The first Iso-resistivity column is a region of aquitard with a semipervious in nature that could transmit water in a slower rate. The second groundwater feature in column 2 is a perch aquifer that could enhance the main aquifer due to interconnectivity and pore pressure of downward-upward migration in confined hydrogeological aquifer setting. Column 3 depicts a complete impermeable feature of aquifuge or aquiclude of subsurface structure with rich in clay sediments or stratum of sediments found at the depth range of 30 m to 270 m. The forth groundwater column indicates a promising water bearing formation, probably sandy in nature with a depth range of 210 to 300 m and thickness of about 90 m. The spatial analysis identified the two locations along the survey areas to be suitable for productive boreholes as well as the trending of the groundwater in the area to be Northwestern Southeast direction. Consequently, the model could be a guide to organize site data, understand site processes and screen for applicability of drilling. These multiple methods of geophysical, spatial analysis and conceptual model could be used a tool for mapping hydrocarbon bearing formation.

Monitoring of Water Quality the Need of Present Day House Hold Water Management

WHO 2019 report on drinking water says that In 2017, 71% of the global population (5.3 billion people)used a safely managed drinking-water service – that is, one located on premises, available when needed, andfree from contamination.. Most countries, the proportions of piped and other-improved water supplies arefaecally contaminated sources due to lack of basic sanitary protection against contamination. Contaminatedwater is an important contributor to water borne disease including hepatitis A,cholera, typhoid, andpoliomyelitis.1 For people with enough water supply can treat their water at home after testing water qualityto ensure microbiological quality. Treating water at the household level or other point of use also reduces therisk of waterborne disease arising from recontamination during collection, transport, and use in the home.This article mainly focuses on need for water quality monitoring,water quality, types of water quality testingthe importance of water quality monitoring and reviews related to water quality testing.

Green synthesis of a silver nanoparticle using Moringa oleifera seed and its applications for antimicrobial and sun-light mediated photocatalytic water detoxification

Natural water resources are rapidly being polluted because of improper treatment of sewage from industrial facilities; accordingly, there is an urgent need for environmentally friendly methods of treatment for this type of waste. Here, synthesis of cost effective, green silver nanoparticles (AgNPs) using Moringa oleifera seed (MOS) as a reducing/capping agent and their applications in antimicrobial and photocatalytic oxidation for water treatment are reported. The results revealed that the MOS-AgNPs were crystalline and spherical, with an average size of 4.0 nm. The MOS-AgNPs showed excellent antimicrobial activity against Gram positive (Staphylococcus aureus; 14.6 mm) and Gram negative (Escherichia coli; 30.6 mm, Salmonella enterica typhimurium (29 mm), and Pseudomonas aeruginosa; 22.8 mm) bacteria. Moreover, the MOS-AgNPs showed remarkable photocatalytic activity toward organic dyes (methylene blue (> 81%), orange red (> 82%), and 4-nitrophenol (> 75%)) under sunlight irradiation. In addition, > 80% of the toxic Pb metal ions were removed from the treated water by MOS-AgNPs. Under similar conditions, the synthesized MOS-AgNPs retained their photocatalytic efficiency after 10 photocatalytic cycles. Overall, these findings indicate that MOS-AgNPs may be a powerful antimicrobial agent against water borne pathogens as well as a promising and economic agent for use in the treatment of waste generated by industrial dyeing processes.

Geo-electric assessment for groundwater potential at permanent site of Waziri Umaru Federal Polytechnic, Birnin Kebbi, Kebbi State North Western, Nigeria

Vertical Electrical Soundings (VES) afford fast and economical measurements used in geophysical exploration. VES was used for groundwater exploration at the permanent site of Waziri Umaru Federal Polytechnic, Birnin Kebbi. Eighteen (18) Vertical Electrical Sounding (Schlumberger array, maximum AB/2 distance 100 m) were performed, data were acquired using ABEM terrameter (SAS 300c), to determine the geoelectric units in the subsurface stratigraphy as well as to delineate groundwater potential in the area via electrical resistivity soundings. Field data collected was analyzed using computer software (IPI2win) which gives an automatic interpretation of the apparent resistivity in ohm-meter. Data was interpreted in terms of the resistivity and thickness of subsurface layers. Results indicates that three to five (3-5) distinct layers in the study area namely; top soil which is mainly sand, clayey sand/loose sand, sandy clay/fine sand and clay unit were delineated. The result also revealed that water bearing formation exists in the third layer in some identified VES locations i.e VES 3, VES5, VES13 and VES14 with very good aquifers, with thickness and corresponding resistivity values of 40.5, 37.5, 45.8, 60 m and 173, 148, 222 and 432 Ωm respectively. The electrical resistivity data, therefore gives reasonable accurate results that can be used to understand stratigraphy and sedimentary configuration in ground water exploration.

Water‑Borne ZnO/Acrylic Nanocoating: Fabrication, Characterization, and Properties.

This work aims to explore how ZnO nanoparticles enhance the mechanical, photoaging, and self cleaning properties of water borne acrylic coating. Micro/nano ZnO particles (at 2 wt.% of total solid resin) were dispersed into the acrylic polymer matrices using ultrasonication to understand the effect of the size of the coating properties. The effect of ZnO particles on the properties of composite coatings (25 µm of thick) have been evaluated through various tests, such as abrasion measurement, ultraviolet/condensation (UV/CON) weathering aging, and methylene blue self cleaning. Experimental data indicated that the incorporation of ZnO particles enhanced both abrasion resistance and methylene blue removal efficiency of the water borne acrylic coatings, with nano ZnO particles being the best. However, the weathering degradation of nanocomposite coatings was more severe as compared to the coating with micro ZnO (at the same ZnO content).

Identification and Comparison of Microbial Load of Different Water Products Available in Ekiti State

The quest for a safe drinking water free from any form of contamination cannot be overemphasized. People around the world do not have safe drinking water and that has resulted into myriad of water borne diseases. A total of twenty-two (22) samples were collected from twelve (12) different brand and subjected to microbiological analysis. From the results obtained, pH of the analyzed samples had ranges from 6.5 to 7.5, which fall within the normal standard range of 6.5 to 8.5.

Evaluation of potential immunotoxic effects of iron oxide nanoparticles (IONPs) on antioxidant capacity, immune responses and tissue bioaccumulation in common carp (Cyprinus carpio)

Nanoparticles can be toxic and put human and animals' life at risk. The present work was carried out to evaluate the possible immunosuppressive effects of water borne iron oxide nanoparticles (IONPs) and the FeCl3 on immune components of common carp (Cyprinus carpio). Fish were exposed to a series of chronic levels of 25%, 50%, and 75% of IONPs LC50 96 h concentration (referred to as control, NP1, NP2, and NP3 respectively) or FeCl3 (same concentrations as IONPs referred to as S1, S2, and S3 respectively) for 21 days. Results revealed alterations in blood parameters, where IONPs significantly decreased number of white blood cells at all concentrations. Glucose and cortisol increased in all exposed fish after 21 days, suggesting activation of the maintenance mechanism cascade against a chronic stressor. IONPs or FeCl3 significantly accumulated in liver tissue of exposed fish. Immune responses were remarkably decreased in serum and skin mucus in response to IONPs or FeCl3. These components were at lowest levels in fish exposed to the highest concentrations of IONPs and FeCl3. The findings of the present study suggested that IONPs is accumulated in fish liver and intestine, where they may exhibit immunotoxicity.

Experimental study of a string-based counterflow wet electrostatic precipitator for collection of fine and ultrafine particles

ABSTRACT Wet electrostatic precipitators (WESP) have been widely studied for collecting fine and ultrafine particles, such as diesel particulate matter (DPM), which have deleterious effects on human health. Here, we report an experimental and numerical simulation study on a novel string-based two-stage WESP. Our new design incorporates grounded vertically aligned polymer strings, along which thin films of water flow down. The water beads, generated by intrinsic flow instability, travel down the strings and collect charged particles in the counterflowing gas stream. We performed experiments using two different geometric configurations of WESP: rectangular and cylindrical. We examined the effects of the WESP electrode bias voltage, air stream velocity, and water flow rate on the number-based fractional collection efficiency for particles of diameters ranging from 10 nm to 2.5 μm. The collection efficiency improves with increasing bias voltages or decreasing airflow rates. At liquid-to-gas (L/G) as low as approximately 0.0066, our design delivers a collection efficiency over 70% even for fine and ultrafine particles. The rectangular and cylindrical configurations exhibit similar collection efficiencies under nominally identical experimental conditions. We also compare the water-to-air mass flow rate ratio, air flow rate per unit collector volume, and collection efficiency of our string-based design with those of previously reported WESPs. The present work demonstrates a promising design for a highly efficient, compact, and scalable two-stage WESPs with minimal water consumption. Implications: Wet Electrostatic Precipitators (WESPs) are highly effective for collecting fine particles in exhaust air streams from various sources such as diesel engines, power plants, and oil refineries. However, their large-scale adoption has been limited by high water usage and reduced collection efficiencies for ultrafine particles. We perform experimental and numerical investigation to characterize the collection efficiency and water flow rate-dependence of a new design of WESP. The string-based counterflow WESP reported in this study offers number-based collection efficiencies >70% at air flow rates per collector volume as high as 4.36 (m3/s)/m3 for particles of diameters ranging from 10 nm – 2.5 μm, while significantly reducing water usage. Our work provides a basis for the design of more compact and water-efficient WESPs.

Review of Abrasion Mechanisms and Influential Variables on The Disintegration Resistance of Concrete

In many hydraulic constructions such as dams, spillways and stilling basins, large of amounts concrete can be damaged depending upon the long-term activity of water-borne solids. To a great extent, for hydraulic structures, the durability relies upon the resistance that the concrete surface offers to mechanical wear. The surface damage caused by the uninterrupted material removal process, induced by the impact of the water borne solid particles, is termed hydro-abrasion. In nearly all hydraulic structures, this kind of progressive deterioration of the concrete surfaces is observed, to different intensities. Obviously, such hydro-abrasive concrete wearing normally results in a reduction in the service life of the hydro-technical facility, and consequently because of the repairs necessitated, the non-functioning of the facility during the repair period results in an expenditure spike. The objective of this article is to: understand the mechanisms of concrete abrasion-erosion followed by brief iscussion about the factors remarkably impact the rate of abrasion erosion also through these studies, it was concluded the improvement of the abrasion resistance needstomodify the concrete characteristics also increase the compressive strength.

U(VI) adsorption by sodium alginate/graphene oxide composite beads in water

Graphene oxide was encapsulated into sodium alginate to prepare SA-GO composite hydrogel for U(VI) adsorption, which characterized by SEM, FTIR, and XPS. The effects of pH, reaction time, initial U(VI) concentration and adsorbent amount on U(VI) adsorption were studied by batch adsorption experiments. The results showed that the maximum adsorption capacity was 149.76 mg/L when pH 5.0, adsorbent 0.1 g/L, 30 °C and initial U(VI) concentration 15 mg/L. The adsorption process accords with pseudo-second-order kinetic models and Langmuir isotherm. After five cycles of desorption and reuse experiments, the adsorption capacity of SA-GO for U(VI) was still higher than 85%.

Ground Water Contamination: Effects and Remedies

Studies on “ground water contamination : effects and remedies” have been conducted, in the light of these, field work studies in Obudu and Obanliku local Government Areas of Cross River State, South Eastern Nigeria, was conducted. Fifteen (15) locations of water for drinking and other domestic uses were carefully studied in the area, with their surface to water depth values recorded. Five(5) of the locations were at surface saturated water depressions(SWD), seven(7) were Hand dug wells(well), while three(3) were bore holes(BH). The physiochemical composition data compared with world Health Organization (WHO) standard shows that, the bore water was safer for drinking than the hand dug wells and surface water in saturated water depressions. Coliform count unite per 100ml of water, were detected in most of the locations in the saturated water depressions and hand dug wells, showing evidence of biogenic interference with the water. Coliform count unite per 100ml of water was not detected in any of the three bore holes, probably due to their depth distance from Biogenic activities. Phosphate and Nitrate levels were significantly above WHO standard in saturated water depressions and Hand dug wells, probably due to erosional and leaching actions of inorganic fertilizers from farm lands and waste from near dump site. It is important to note that most water borne diseases are as a result of ground water communication with contaminant, such as heavy metals, leachate from dump sites, pollutants from inorganic fertilizers, pith toilets sea water intrusion etc., most boreholes are contaminated by these processes. This is one of the reasons for the increase in the rate of cancer in most developing countries. Hence, heavy metals are known to be carcinogenic to the human cells, and also can cause mutation. The remedies to these include:
 
 The process of exploiting and storing ground water should be done with all safety precautions, such as making sure biochemical parameters in water are in line with WHO standard
 Thorough biochemical analysis and test for the presence of heavy metal contamination and coliform count and other contaminants should be done on ground water, before use for domestic and industrial purposes.
 Surface depth measurement of recharge zones in boreholes should be carried out to ensure that borehole water is from confined aquifers that are safe for domestic and industrial uses.
 Proper waste disposing system such as engineered toilet pits, engineered dump sites and effective management of electronic waste should be monitored and implemented
 Where the purity of the water is not satisfactory, such water should be properly treated before used for drinking and other domestic purposes.

ENVIRONMENTAL AND HEALTH EFFECTS OF CLIMATE CHANGE IN KADUNA METROPOLIS

This study examined environmental and health effects of climate change in Kaduna metropolis. Primary data were obtained through randomly administered 184 structured and semi structured survey questionnaires to purposefully selected groups of people, workers and students in the metropolis. Secondary data were obtained from desk reviews of other literatures and interviews of staff of Nigerian Metrological (NiMET) Agency and Ministry of Environment Kaduna. Descriptive statistics using Likert rating scale was employed for the analyses of the data. Findings revealed percentage range of strongly agree and agree of 80% - 59.8% that climate change has negative environmental and health effects in Kaduna metropolis. The environmental effects identified are: flooding, desert encroachment, drought, land degradation, run-off, soil erosion, loss of water resources and biodiversity and poor agricultural productions while the health effects are: hyperthermia, vector and water borne diseases (cholera, malaria), heart ailments, dehydration and diseased crops. The study also discovered that the comprehension of the concept climate change in the metropolis is limited. Finally, the study recommends intensive public education and enlightenment on the causes and effects of climate change, strong legislations and enforcement of environmental laws and adaptation measures.

Assessment of Physicochemical and Microbiological Quality of Table Water Sold in School Campuses of the University of Port Harcourt, Nigeria

Water is the elixir of life which is essential for proper metabolic processes to take place. The quest for cheap and readily available source of potable water has led to the emergence of sachet and bottle water which the sale and consumption continue to grow astronomically and rapidly in most countries of the world. This study was aimed at assessing the microbial and physicochemical water quality of table water sold on School campuses. Standard microbiological procedures were used to isolate and identify various microbial genera associated with the water samples using morphological, microscopic and biochemical characterization method. The bacterial genera identified were Escherichia sp., Streptococcus sp., Micrococcus sp., Vibrio cholera., Staphylococcus sp. and Bacillus sp. with Choba campus having the highest microbial contamination of packaged water. However, the results of the physicochemical properties from this study were all below the WHO recommended limits. The temperature and pH ranged between 26-27°C and 6.98-7.08, respectively. The values of the electrical conductivity ranged from 0.080 to 0.150 µs/cm; turbidity ranged between 0.40-1.40 NTU; chloride ranged between 1.187-2.103 mg/l, nitrate was within the range of 0.01 to 0.14 mg/l; BOD ranged from 0.02-0.04 mg/l, COD was between 0.00-0.08 mg/l and the total soluble solids were between the ranges of 0.04-0.10 mg/l. Therefore, this study suggests the improvement of water-borne disease preventive and control measures, and monitoring of water quality by the regulatory agencies to ensure good manufacturing practices by the water bottling companies which will result in reduction of health hazards associated with water borne diseases.

Groundwater Inrush Control and Parameters Optimization of Curtain Grouting Reinforcement for the Jingzhai Tunnel

Based on the systematic study on the characteristics of water and mud inrush during the excavation of Jingzhai tunnel, the mechanism of water inrush seepage transformation caused by excavation disturbance is analyzed. By means of electromagnetic geophysical prospecting, the potential water bearing area of the tunnel was analyzed. The constitutive model of rock mass and grouting parameters are considered in the numerical simulation. The law of tunnel crack initiation and expansion under different curtain grouting parameters is proposed. The characteristics of seepage water inrush caused by excavation are described. It is considered that there are three stages in the seepage characteristics of tunnel: incubation, sudden, and stable. Numerical simulation was used to analyze the crack propagation track and water inflow characteristics under the grouting thickness of 3 m, 5 m, and 7 m. When the curtain grouting thickness was 3 m, the fracture field penetrated the curtain grouting area. The dominant seepage channel is formed, which greatly increases the probability of water inrush. When the curtain thickness is 5~7 m, the expansion of the crack zone can be controlled basically, so that the fracture and water bearing rock layer cannot form a seepage channel. At last, the grouting scheme of 6 m thick grouting and 20 m advanced grouting was selected, and the water seepage was reduced by 83%.