bluuebunny/crossref_metadata_2025 huggingface dataset:
Turmeric Potency in Preventing Aeromonas hydrophila Infection in Clarias batrachus
Authors: Riauwaty Morina , Siregar Y I , Mulyani I
Published: April 2021

A study on clinical signs of Clarias batrachus that was fed with turmeric enriched pellets and was infected with Aeromonas hydrophila has been conducted from May to August 2020. This study aims to understand the effects of turmeric in preventing the disease due to A. hydrophyla infection. There were 5 treatments applied, namely Po (no treatment) and Pp (infected with A. hydrophyla, no turmeric), the fishes were fed with 0.5 g/Kg turmeric enriched pellets (P1), 0.7 g/Kg (P2) and 0.9 g/Kg (P3). The fishes used in this study were 10-12 cm (TL) and 13-15 g (BW) and were distributed in 15 aquaria of 50 L (n=10 fishes/aquaria). The fish was fed with turmeric enriched pellets and by the 30th day, the fishes were infected intramuscularly with 0.1 ml of A. hydrophila suspension. In the 14th day after injection, any clinical signs occur were noted. Results shown that the Pn was normal, the Pp shown very bad condition with ulcers, skin lession, frantic swimming, haemorrhage spots and exopthalmia. The fish that were fed with turmeric enriched pellets shown lighter signs. In P3, ulcers occur in the 3th, but it became better by the 12th day. Based on data obtained, it can be concluded that the provision of turmeric enriched pellet is effective to cure the clinical signs of A. hydrophila attack.
Length-Weight Relationship and Condition Factor of Macrobrachium rosenbergii in Kuala Cenaku River, Indragiri Hulu Regency, Riau Province
Authors: Fauzi M. , Efizon D. , Windarti  , Hermawita A.
Published: April 2021

The aim of this research is to understand the length-weight relationship and condition factor of Macrobrachium rosenbergii from the Kuala Cenaku River, Indragiri Hulu Regency. The samples were collected monthly from Mei-July 2020. A total of 297 of M. rosenbergii was caught by fish trap and nets in 4 stations. The average lengths of M. rosenbergii at each station are: 127.2, 151.1, 130.9 and 120.9 mm. The factor conditions range from 0.829345 to 0.93729392. The relationship between length and weight has a determinant value (R2) ranged from 82%-93%. The condition factor of M. rosenbergii at each station is 1.10, 1.16, 1.11, 1.13 respectively and the value of the factor condition was more than 1, indicates that the giant prawns found in the waters of the Kuala Cenaku River is rather fat. This fact indicates that there is a correlation between conditions environment and food availability in the body shape of M. rosenbergii.
Analysis Strength Structure Fising Vessel of Composit Sandwich Plate System Using Finite Element Method
Authors: Romadhoni  , Santoso Budhi , Nasution Polaris
Published: April 2021

Fiberglass composite material is currently widely used as an alternative material or substitute material for metal and wood materials for the manufacture of fishing boats, because it has its own advantages, among others, easily formed in accordance with needs, has good strength and stiffness. However, in the operation of the ship the bow section often experiences a collision or collision so that when the ship is operating and leaning on the dock which causes a collision where the kinetic energy of the boat turns into a collision energy absorbed by the boat’s hull that is hit by a collision. The energy damaged the hull of the boat that was hit, so the front of the ship needs to be done by adding a new material that is a composite sandwich made with the aim of optimal weight efficiency, but has high rigidity and strength. There are many variations in the definition of sandwich composites, but the main factor of the material is the lightweight core, thus reducing the specific gravity of the material and the strength of the skin layer which gives strength to the sandwich composite. This research was carried out a static structural analysis of composite sandwich material using Ansys Workbench 14.5 software. A model is designed and analyzed using 3D CAD software, which is fore ships that have the potential to experience collisions. From the simulation results of the Fenite element method, the maximum principal stress of the model shows that the maximum point is 11.6 MPa. The maximum stress occurs at the ivory bottom, which is 6.9759 kN/m2 or 6.97 kPa, this occurs due to the bow of the fishing boat experienced a great imposition.
Design of Submerged Fixed Bed Filter for High Density Shrimp Culture in Recirculating Aquaculture System
Authors: Thesiana L. , Adiyana K.
Published: April 2021

Shrimp is Indonesia’s the leading export commodities from Indonesia, but in recent years the shrimp industry has been threatened by disease outbreaks due to environmental quality decline. To overcome these challenges, there is a need for a cultivation technology which provides opportunities for intensive shrimp culture in a narrow area, resulting high productivity and having less environmental impact. Recirculating aquaculture systems (RAS) was the best option to provide high density shrimp culture without leading to environmental damage due the system equiped with water treatment unit. This study aimed to design a submerged filter which can be used in commercially recirculating systems for high density shrimp culture. Submerged filter as water treatment unit for ammonia conversion, it was designed based on organic load mass balance derived from feeding regimes. A RAS with 8 m3 volume capacity use for rearing 400 shrimps m−3, has dissolved oxygen levels range between 6-7 mg L−1, nitrification rate 0.45 g TAN m−2day−1 and TAN levels <1.8 mg L−1, based on spreadsheet calculation will require submerged filter media with 0.07 m3 in volume, media depth 0.3 m, and filter media specific surface area 1200 m2 m−3. Submerged filter design for high density shrimp culture in a narrow place must have a compact design. It can be achieved by selecting filter media type with large specific surface area values. Filter media with a large specific surface area makes biofilter design has smaller dimensions. Submerged filter as water treatment unit in recirculating system for high density shrimp culture will reduce TAN level in water. Waste water in this system is reuse for shrimp culture, no waste water disposal to the environment which leading to sustainable aquaculture practice.
Effect of Thyroxine Hormone on Growth and Survival Rate of Bronze Featherback (Notopterus notopterus, Pallas 1769)
Authors: Sukendi  , Thamrin  , Putra R M , Yulindra A
Published: April 2021

Bronze featherback (Notopterus notopterus, Pallas 1769) is an Indonesia’s endemic fish that has high economic value. This study was conducted from July to August 2020 in Sungai Geringging Village, Kampar Kiri District, Riau Province to determine the effects of thyroxine (T4) on growth and survival rate of bronze featherback for 40 days. The experiment lasted for 40 days and used a completely random design with four treatments and four replications. Treatment were P1 (0 mg thyroxine/kg feed), P2 (2 mg thyroxine/kg feed), P3 (4 mg thyroxine/kg feed) and P4 (6 mg thyroxine/kg feed). The fish caught from the Kampar river were reared for 40 days in 1x1x1 m3 with five individuals. per cage. Fish treated in P4 demonstrated high growth in terms of absolute weight (10.05 ± 0.53 g), absolute length (5.27 ± 0.96 cm), daily growth rate (2.97 ± 0.22%) and larval survival rate (95 ± 10%).
The Influence of Coastal and Marine Ecosystem Conditions on Fisheries and Socio-Economic Activities of Local Fishermen
Authors: Hidayati D.
Published: April 2021

Fisheries and socio-economic activities of fishermen, especially traditional local fishermen, largely rely on coastal and marine ecosystem condition. Degradation of coastal and marine resources, particularly coral reefs and fish, is widespread as a result of the increase in pressures on these resources, which tends to continue in parallel with the increase of economic activities in the coastal areas. The high potential of coastal and marine resources has triggered fishermen from outside to utilize these resources for profit without paying attention to their sustainability. This situation creates high competition over resources, leading to conflict of interests and overlapping fishing areas between local and domestic fishermen, as well as those from neighbouring countries. The local fishermen are in a weak position; their fleet, fishing equipment and bargaining position are much worse than the outsiders. Meanwhile, climatic conditions, especially the more frequent extreme weather, also have a major impact on fisheries activities, production and fishermen incomes. This paper discusses these issues in Natuna District, Riau Islands Province, Indonesia. It uses empirical data from Indonesian Institute of Sciences (LIPI) and my related research activities in this location. Data is also collected from secondary sources, including related books, papers, documents, and research results.
Growth of Microalgae Spirulina platensis on Media Containing Palm Oil Mill Effluent
Authors: Effendi I. , Nurrachmi I. , Tarigan A. N. F.
Published: April 2021

Spirulina platensis, a Cyanobacteria, is used as a natural food in fish hatcheries and a food supplement for humans. These microalgae are very nutritious, containing 63-68% protein, 18-20% carbohydrates, and 2-3% fat. Increased production of palm oil has serious side effects on the aquatic environment due to the disposal of palm oil mill effluent (POME). POME are thought to be suitable as nutrients and media to microalgae. This study aimed to determine the effect of POME with different nutrient variations on the growth of these microalgae. This study used a randomized block design (RBD) with 2 factors, namely factor A (POME concentration) which consisted of 3 levels, namely 20 ppm (A1), 40 ppm (A2), and 60 ppm (A3) and factor B (media) namely Walne (B1), and Guillard (B2) with 3 repetitions. The results showed that the addition of POME had positive effect on the growth of S. platensis. The higher the POME concentration the better the growth rates obtained for both types of media. For Walne medium, the best growth was obtained on day 10 of A3B1 (69,447.98 sins/ml). Meanwhile, for Guillard medium, the highest growth was achieved on day 8 of A3B2 (82,027,6 sins/ml).
The Occurrence and Distribution of Microplastic in Sediment of the Coastal Waters of Bengkalis Island Riau Province
Authors: Amin B. , Febriani I. S. , Nurrachmi I. , Fauzi M.
Published: April 2021

The presence of microplastics, which was defined as small pieces of plastic less than 5 mm in size, in the aquatic environment has become a global concern these days. Once in the aquatic environment, microplastics might float in the water column or sink to the bottom sediment, depending on the particle density. This study was conducted in the coastal waters of Bengkalis Island in early 2020 with the aim to determine the occurrence and distribution of microplastics in sediment from six stations with suspected different sources of pollutant input. Sediment samples were taken using the PVC pipe at the depth of 0-10 cm, brought back to laboratory, observed the types and calculated their abundance. The results of the study showed that the highest abundance of microplastics was found at station 6 (83.33 and 26.67 particles/kg for fiber and film) and the lowest abundance was at stations 2 (30.00 particles/kg for fiber) and station 3 (10.00 particles/kg for films). The abundance of fiber type between stations was significantly different (p<0.05), but not for film type (p>0.05). The abundance of microplastics based on colour in each type showed that the highest abundance was in blue colour for fiber and white colour for film type. The abundance of microplastics in the northern part was found to be significantly (p<0.05) higher than in the southern part of Bengkalis Island which was assumed to be due to differences in oceanographic characteristics in both areas such as differences in the type and size of the sediment substrate.
Growth and Enzyme Production of Proteolytic Bacteria from Mangrove Sediment
Authors: Nursyirwani N. , Samiaji J. , Tanjung A. , Effendi I. , Claudia K. M.
Published: April 2021

Accumulation of organic component in mangrove ecosystem results in diversity of microorganisms producing extracellular enzymes. Two species of proteolytic bacteria had been isolated and identified from sediment of mangrove ecosystem in the Dumai Marine Station of Riau Province, Indonesia. This research aimed to assess the activity and enzyme production of the proteolytic bacteria, i.e. Bacillus manliponensis (isolate code P.Az6) and B. toyonensis (P.Az20). The growth of bacteria in tryptic soy broth (TSB + skimmed milk) was observed by using spectrophotometer at λ 610 nm and by analysis the total plate counts on Zobell Marine Agar at 0, 6, 12, 18 and 24 hours. Production of enzyme protease was measured from the absorbance values of bacterial supernatant, then were conversed to the protease concentration by using the Bovine serum Albumin Standard. The highest bacterial growth and optimal enzyme production was observed at 6 hours incubation, and period after that showed decrease in growth enzymatic activity. Bacillus toyonensis showed higher bacterial growth and enzyme production than B. manliponensis.
Characteristics of Oil Mixed Red Palm Oil with Catfish Oil (Pangasius hypothalmus)
Authors: Dewita  , Syahrul  , Irasari  , Sumarto
Published: April 2021

Riau Province is the region that has the largest plantation area in Indonesia with 2.4 million hectares of land in 2017 and production contributes 6 million tons per year and contributes 28.2 percent of Indonesia’s total CPO exports. On the other hand, the Kampar and Pelalawan districts are centers for the production of special freshwater fish for catfish (Pangasius hypoptalmus), where from year to year they have increased rapidly. This study aimed to charaterized oil mixed of red palm oil and catfish oil byproduct of catfish fillet. This research was conducted using a one-factor factorial experimental method, namely the difference in the ratio of the mixture between red palm oil and catfish oil. Red palm oil and catfish are stirred in a ratio of 70: 30 (B1), 60: 40 (B2), and 50:50 (B3). A serial of organoleptic and chemical test (saponification rate, iodine number, number acid, and fatty acid profile) were carried out. The results showed saponification rate was - 295.36, iodine concentration was 80.33 and acid number was 0.05. Furthermore, the fat content of each ratio B1 (14.28%, B2 (16.21% and B3 (17.11%), while the types of fatty acids obtained are saturated fatty acids (SAFA), unsaturated fatty acids single (MUFA) and polyunsaturated fatty acids (PUFA). The quality of the mixture of red oil and catfish oil produced in this study meets the FDA (Food and Drug Administration) standards, in which the best one was B3 (50: 50). It can be interpreted that the mixture can be used as a source of fatty acids needed by the body which contains omega-9 fatty acids, omega-6 and omega-3.
Fortification of Rebon Shrimp Protein Hydrolysate (Acetes erythraeus) in Sago Flour as a Nutritious Food
Authors: Suparmi S. , Warningsih T. , Dahlia D. , Sidauruk S.W.
Published: April 2021

Rebon shrimp protein hydrolyzate as a non-conventional processed product has a high protein content which is the potential to be used to enrich the nutritional value of food ingredients such as sago flour. This study aims to determine the appropriate concentration of rebon shrimp protein hydrolyzate for enriching the nutritional value of sago flour. The addition of protein hydrolysate used 3 levels of concentration, those were 10% (F1), 15% (F2) and 20% (F3). The best treatment is F3. Fortification of rebon shrimp protein hydrolyzate in different amounts has an effect on the proximate value of sago flour, the best treatment is a concentration of 20%. with a water content of 10.49%, 4.85% ash, 24.56 protein and levels. fat 1.76%. Hedonic test indicated the taste value of 8.7, aroma 8.6, appearance value 8.7 and texture value 8.6. The content of amino acids is 17 types with 9 essential amino acid. The essential amino acids are histidine, arginine, threonine, valine, methionine, isoleucine, leucine, phenylalanine and lysine. The 8 types of non-essential amino acids are aspartic acid, glutamic acid, serine, glycine, alanine, proline, tyrosine and cysteine. The highest essential amino acid content was leucine at 2.75% and the highest non-essential amino acid content was glutamic acid at 4.52%. Based on the research results, it can be suggested for the enrichment of the nutritional value of sago flour to add 20% protein hydrolyzate of rebon shrimp and it can be used as a nutritious food.
Comparison of land cover classification in Pakpak Bharat Regency using Landsat 8 OLI and Sentinel 1A satellite imagery
Authors: Slamet B , Gaol M L L , Samsuri  , Rauf A
Published: April 2021

The increase in population impacts the need for land as a source of living that is increasing. The area of forest in Pakpak Bharat District decreased by 17.4% for the period 2011 to 2015. This study aims to identify land cover in Pakpak Bharat District by using Landsat 8 OLI Optical Imagery and Citra Radar Sentinel 1A. Sentinel SAR images 1A are converted first to be visually analyzed, and classification can be performed using the maximum likelihood method. The analysis carried out is a separability test, kappa accuracy test, and validation test. The calculation of kappa accuracy and validation shows that Landsat 8 OLI imagery has higher accuracy, which for Landsat 8 OLI and Citra Radar Sentinel 1A were 95.26% and 4.92%, respectively. Validation test results for Landsat 8 OLI and Citra Radar Sentinel 1A were 83.87% and 18.28%. The results indicate that the classification of land cover from Citra Sentinel 1A using the maximum likelihood supervised classification method does not provide satisfactory classification results. Although constrained by clouds, Landsat 8 OLI imagery for land cover classification using the maximum likelihood method is still better.
Effect of altered salinities on the growth and root performance in Ceriops tagal seedlings
Authors: Basyuni M , Lubis M U , Utomo B
Published: April 2021

Mangrove forests degradation caused by anthropogenic activities leads to a decrease in the composition of mangrove forests. Mangrove forest rehabilitation activities, therefore, are needed to improve mangrove forest ecosystems. Research on the growth and development of true mangrove seedling roots of Ceriops tagal on various salinity was examined in a greenhouse, Faculty of Agriculture, Universitas Sumatra Utara. This study used a non-factorial Complete Randomized Design with 5 treatments salinity (0%, 0.5%, 1%, 2%, and 3% concentrations) and repeated with ten replications. Results showed that 0.5% salinity concentration dominated the observed parameters, such as seedling growth height, seedling diameter, number of leaf count, leaf area, leaf thickness, root diameter, canopy water content 0.5%, and root and shoot ratio. By contrast, the highest shoot water content was at 0% salinity and root length at 2.0% salt concentration. This study indicated that the best growth of C. tagal seedlings was at 0.5% salinity concentration because more than 80% of parameter measurements were at 0.5% salinity concentration.
Molecular identification, characterization, and antimicrobial activity of isolated lactic acid bacteria from dali ni horbo
Authors: Siburian I R R , Lister I N E , Ginting C N , Fachrial E
Published: April 2021

Various dairy products come from Indonesia and are fermented that leading to the growth of lactic acid bacteria. According to bataknese culture, water buffalo milk can be fermented to form Dali ni Horbo. This study was aimed to isolate, characterize, molecular identification, and evaluate the antimicrobial effect from the lactic acid bacteria in Dali ni horbo. Dali ni horbo as the sample was encoded D1, D2, and so on. The lactic acid bacteria were isolated from Dali ni Horbo by MRSA. Moreover, the colonies of bacteria were enriched into some isolates. After that, the isolates were characterized by gram staining, catalase, and type of fermentation. Meanwhile, to evaluate the antimicrobial activity, this study used the disc diffusion test against two different pathogens. At last, the selected isolate was molecularly identified from the 16S rRNA marker. Dali ni horbo contain 4.3 x 108 CFU/ml. of Lactobacillus fermentum strain A1753 The isolated bacteria were bacilli-shaped, positive gram, homofermentative, and heterofermentative bacteria without catalase activity. The isolated bacteria have potent antimicrobial activity against the negative pathogen (ranged from 9.8 mm – 12.15 mm) than positive gram pathogen (ranged from 7.15 mm – 11.05 mm). Hence, Dali ni horbo contain lactic acid bacteria that can be natural preservative and potential probiotic.
Application of pumping and rice planting patterns to improve the productivity of fresh water swampy rice fields in South Sumatra, Indonesia
Authors: Hasbi  , Tunggal T , Herlinda S , Irsan C , Huljanna R M
Published: April 2021

Productivity of the fresh water rice fields is currently relatively low due to various factors such as cropping patterns and water factors. This study aimed to compare four cropping patterns in cultivation of swampy fresh water rice. The four cropping patterns consisted of the cropping patterns of Farmer Entrepreneurs, Conventional Farmers, Fostered Farmers of Jajar Legowo Super, and Fostered Farmers of Tegel Diairi. The study used descriptive method by collecting primary data presented in tabular forms. The primary data were the plant height (cm), maximum number of tillers (stems/clumps), productive tillers (stems/clumps), panicle length (cm), number of grains/panicles, dry weight of biomass and grains of rice, weight of 1000 grains (g), and land productivity (tons/ha). The study was conducted in Pemulutan Subdistrict, Ogan Ilir District of South Sumatra. The cropping pattern of Fostered Farmers of Jajar Legowo Super with the pumping was the best treatment viewed from the agronomic performance, namely the highest number of grains per panicle of 115.72, the number of pithed grains per panicle of 110.53, weight of 1,000 grains (g) of 22.07 and grain productivity of dry harvest of 7.33 tons/ha. The treatment of conventional farmers’ cropping pattern was the lowest one in terms of the lowest number of grains per panicle which was 72.24, the number of pithed grains per panicle which was 67.43, the weight of 1,000 grains (g) which was 18.55, and the productivity of dry grains which was 1, 69 tons/ha.
Exploration of data on the formation of two mangrove seedling species to establish a growing stability point
Authors: Bimantara Y , Basyuni M , Selamet B
Published: April 2021

Avicennia alba is one of the best mangrove colonies. A. alba seems to adapt well to grow stably on dynamic flat mud. A. alba species through their root growth, vare able to rely on sediments quickly, resist the hydrodynamic force of waves and tidal currents within a few days and then withstand the movement of sediments in the upper sedimentary layers. While from Ceriops tagal propagules and Rhizophora mucronata, after falling from the mother tree, certain dehydration levels stimulate the initiation of root formation as a sign to show dormancy propagules. As a result, root formation cis delayed when propagules float in the sea during dispersal. Meanwhile, the formation phase of mangrove propagules is faster in conditions of low salinity than in conditions of high salinity, and if during the rainy season, conditions for propagules’ information are better. However, these two species follow different strategies for the distribution and formation of mangrove zoning, and these findings contribute to the explanation of the distribution of different species.
Natural regeneration potential of red meranti (Shorea leprosula Miq.) in 20-years-old man-made hilly dipterocarp forest
Authors: Pamoengkas P , Rachmat H H , Nurkhaeni W , Susilowati A
Published: April 2021

Shorea leprosula Miq is one of major tropical timber within the dipterocarp family and known as red meranti in global trade. The species has been subjected to intensive timber extraction due to their high economic value and natural abundance in primary tropical forest. Timber supply of this species has been known to only from natural forests and none have been reported from commercial plantation. Thus, population decline, habitat contraction and local extinction become the major issues related to the species. This research was conducted to determine the natural regeneration potential of S. leprosula in 20-years-old man-made hilly dipterocarp forest. The research was located at Gunung Dahu Research Forest (GDRF), a 250 Ha-mixed dipterocarp forest established since 1997 in Bogor-West Java as landscape restoration together with native biodiversity conservation program. Five S. leprosula plots were chosen consisting from different spacing distance of 2 m x 2 m, 3 m x 3 m, and 4 m x 4 m. Result showed that each plot has been experiencing different total number of fruiting times, ranging from 1-3 times, with total numbers of natural juvenile reached 652 stocks. Among them, seedling were the most stocks available at GDRF, with the most dominant occupied at height class of 11 cm – 33 cm and 34 cm – 55 cm. Natural stocks were absent from 2 observed plots due to high human alteration at those area. Canopy openness, altitude and human intervention/disturbance are among the factors that affecting the regeneration potential at GDRF.
The properties of particleboards made from corn stalks and bagasse at various compositions
Authors: Iswanto A H , Tarigan I G , Nuryawan A , Oktaviani F
Published: April 2021

Corn stalks and bagasse are materials that contain lignocellulose and have the opportunity to be used as raw material for particleboard manufacturing. This study aims to analyze the effect of the composition of corn stems and bagasse on the physical and mechanical properties of particleboards. The composition of corn stalk and bagasse as raw material for making particleboard in this study consists of several ratios, namely 100/0, 80/20, 60/40, 40/60, 20/80, and 0/100. The adhesive used in this research was isocyanate. The thickness and target densities were 1 cm and 0.70 g/cm3, respectively. The results showed that the board density value did not reach the target, and the thickness swelling of the board was still quite high. Board with a composition of a mixture of corn stems and bagasse at an 80/20 ratio is a board that has better properties compared to other ratios.
Effect of Water Film Thickness (WFT) on the Fluidity, Rheology, Cohesiveness and Segregation Resistance of Multi-Mineral Cement Paste
Authors: Tian Zhenghong , Liu Hengrui , Sun Xiao , Ma Yuanshan
Published: April 2021

The main purpose of this paper is to investigate the effect of water film thickness (WFT) on grouting performance. To this end, the relationship between WFT and rheological parameters, flow parameters, segregation resistance and cohesiveness was established by mathematical statistical methods and regression analysis. The results show that the WFT is the most significant factor in determining the fluidity and rheology of the cement paste. In engineering, WFT can be used to characterize the fluidity and rheology of the grout. WFT is not the only factor that determines the cohesiveness of cement paste, but there is a good dynamic correlation between WFT and cohesiveness. The correlation between WFT and bleeding rate increases with time, which is caused by the physical sedimentation process of the particles.
Application of Secant Piles for Excavation Pit in Complicated Environment
Authors: Cui Meng , Fu Xiao , Hu Linna , Liu Hailin
Published: April 2021

In order to study the application of secant pile in deep foundation pits in complex environments, this paper takes an actual foundation pit project as the research background, and combines the characteristics of the deep excavation of the foundation pit and the large influence of the groundwater level. Propose the design scheme of partition and segment and use finite element analysis method for numerical calculation. By calculation it is known that the overall displacement of the foundation pit support system is 13.11 mm, the maximum horizontal displacement is 11.8 mm, and the ground settlement is 5.7 mm. All indexes meet the requirements of foundation pit specifications. The research results show that the secant pile has its unique advantages and applicability, which can effectively stabilize the overall performance of the foundation pit and the surrounding environment. The design philosophy in this article can provide references for similar foundation pit projects.
Analysis of Obstacle in Promotion of Smart Construction Site Based on ISM- MICMAC Model
Authors: Lin Peng
Published: April 2021

As the “last kilometer” of building information management, Smart Construction Site has not landed successfully. It is significance to accurately identify and analyze the obstacles in popularization. Based on the eight obstacle factor indicators defined by factor analysis, we set up an interpretation structure model (ISM) for the promotion of barriers in smart construction sites, and obtain the three-level hierarchical relationships among various factors. Then, MICMAC analysis method was used to calculate the dependency and driving force of each factor, and the interaction between each factor is obtained. Combining ISM and MICMAC analysis results, the obstacles to implementation are the deep-rooted obstacles in the promotion of smart construction sites, while it is linked with economic and target barriers, and has strong relevance. Therefore, three obstacles should be considered as a whole for comprehensive and effective monitoring to ensure the stability of smart construction sites used by construction enterprises.
Dynamic Performance of High Liquid Limit Clay under Vehicle Load
Authors: Miao Lei , Wu Wenjuan , Hu Peiqing , Zhang Xiaomeng , Yang Yongfu , Chen Tingting
Published: April 2021

High liquid limit clay is widely distributed in China with its special properties. GDS dynamic triaxial test was carried out to investigate its dynamic response under vehicle load in the article. The response law of the accumulative strain and plastic modulus of the high liquid limit clay under different dynamic stress amplitude, cycle times, compaction, water content and confining pressure was attained. The research results have important reference value for the design of high liquid limit clay subgrade.
Experimental Study on Physical Properties of Octadecylamine Modified Expansive Soil
Authors: Wang Maosheng , Liu Jiaming , Ao Weichao , Qi Shoudong , Wu Junhua
Published: April 2021

Taking weak expansive soil as the research object, octadecyl primary amine (octadecylamine) was mixed into remolded expansive soil as a water repellent, and modified samples with different octadecylamine content were configured. The water-repellent grade of the modified expansive soil was measured by the dripping water penetration time method, the boundary moisture content test of the modified expansive soil was carried out, and the change law of the liquid plastic limit of the modified expansive soil with different octadecylamine content was analyzed. The results show that with the increase of the octadecylamine content, the liquid limit of the expansive soil gradually decreases, the plastic limit gradually increases, and the plasticity index gradually decreases. The above research results can provide a test basis for the engineering application of modified expansive soils.
Analysis of Fractal Features of Blasting Vibration Signal Based on EEMD Decomposition
Authors: Song Xiaolong , Gao Wenxue , Li Jingyan , Wang Lintai , Cao Xiaoli
Published: April 2021

In order to study the propagation characteristics of blasting seismic waves by using the analysis and research of blasting vibration monitoring data of Urumqi subway tunnel excavation, the blasting vibration signal has been decomposed into several IMF components by EEMD decomposition and fractal theory has been used to calculate the correlation dimension in this paper. The results show that the IMF component can reveal the frequency characteristics in the blasting vibration signal clearly. As the measuring point is far away from the explosion source, the complexity of the frequency component of the vibration signal gradually decreases. The seismic wave interacts with the rock and soil medium in the propagation process, make it shown non-linear characteristics, which are not easily to be observed by conventional measure methods. This paper introduces fractal dimension to study the nonlinear characteristics of blasting vibration signals and achieves the purpose of analysing the law of blasting seismic wave propagation. This study achieves a quantitative description of the effects of site media on seismic waves, and at the same time, it lays a theoretical foundation for predicting the vibration effect analysis of seismic waves reaching the target position.
Strength Characteristics of Reinforced Granular Soils in Three-Dimensional Space
Authors: Dong Qi , He Yuqi , Liao Hongjian , Niu Bo , Zhang Liang
Published: April 2021

A series of true triaxial numerical tests were carried out on reinforced granular soils based on DEM method, effects of reinforcement layers and intermediate principal stress ratio on the strength characteristic of granular soils were conducted. The simulation results show that the shear strength of reinforced soils can be improved with the increase of reinforcement layers. However, the improvement effect becomes weak with increase of the intermediate principal stress ratio. Furthermore, the shear strength of granular soils will decrease with the increase of intermediate principal stress ratio b under constant P stress path, the maximum shear strength can be obtained in case of b=0 test, while the minimum shear strength appears under b=1.0 condition.
Numerical Analyses on Geogrid-Reinforced Cushion in Pile-Supported Composite Foundation
Authors: Zhang Wen-bing , Shu Wei-peng
Published: April 2021

A numerical analysis is conducted on the performance of geogrid-reinforced cushion in PCC pile-supported composite foundation for highway embankment applications. The finite element method is employed to simulate the behavior of cushion under loads. Soil arching effect and tensile membrane effect are two factors affecting cushion behavior. Two parameters, i.e. geogrid tensile strength and laying arrangement, are found effective in measuring soil arching and tensile membrane effects. Numerical analyses indicate that an increased geogrid tensile strength contributes to a reduced embankment settlement. The effect of geogrid laying arrangement on settlement is relatively small.
Measured Deformation of Pipe-Roof during Box Culvert Jacking in Soft Ground
Authors: Cheng Chihao , Liu Mengbo , Liao Shaoming
Published: April 2021

RBJ method is suitable for shallow covering and micro-disturbed underpassing project. In this paper, the pipe deformation induced by box culvert jacking is analyzed. The research shows that: (1) The closed pipe-roof frame presented a phenomenon of expanding outward, namely the uplift of top pipe and the settlement of bottom pipe. (2) Along the jacking direction, the deformation of pipes was positioned over the box culvert structure and about 10m in front of the excavation face. (3) Due to the bounded constraint of diagram wall, it’s prone to be a reverse deformation at joint between pipe and diagram wall, and resulting in a wave-type deformation pattern.
Experimental Study on Vibration Platform under the Coupling Action of Soil-Metro Upper Cover Structure
Authors: Han Xuechuan , Tao Lianjin , An Shao , Zhang Yu
Published: April 2021

In order to study the seismic response law of the Upper Cover Structure station system, the shaking table test was carried out on the silty sand site with the subway superstructure system and single subway station structure as the research objects. Firstly, the general situation of shaking table test is introduced. Then, the seismic response of subway station structure is studied from two aspects including acceleration and strain, and the test results are compared. The test data show that: (1) With the increase of input seismic intensity, the acceleration peak value of soil and monitoring points of the same structure increases gradually, while the acceleration amplification coefficient decreases gradually. (2) With the increase of earthquake intensity, the tensile strain amplitude of the superstructure-subway station structure increases gradually. In the model, the tensile strain amplitude at the end of the column is the largest, followed by the side wall and the floor is the smallest. (3) The acceleration and strain of the superstructure-subway station system are less than those of the single subway station structure, in which the acceleration variation law is roughly the same. The difference of strain amplitude gradually increases with the increase of earthquake intensity, and the change rate of strain peak value gradually increases and converges.
Wind Stability Analysis of 4000m-Span Suspension Bridge with Carbon Fiber Spatial Cable System
Authors: Yuan Weiwei , Xu Wenping
Published: April 2021

In order to solve problems of the low utilization ratio of the material of main cable and wind instability of suspension bridges with super-long-span steel main cables, ANSYS is used in this paper to establish models of a spatial cable suspension bridge and a parallel cable suspension bridge respectively. The dynamic mode, static wind stability and flutter stability of the models are compared by the software. The results show that the spatial suspension bridge has tensional vibration appearing much later, a higher frequency of the cable system, and a higher critical wind speed and a higher critical wind speed for the flutter, compared with the parallel cable suspension bridge. Therefore, the spatial suspension bridge has better wind stability.
Traffic Accident Risk Factor Identification Based on Complex Network
Authors: Chen Yang , Deng Yuanchang
Published: April 2021

Identifying the risk characteristics of traffic accidents is of great significance for in-depth understanding and promotion of traffic safety. 85 serious traffic accidents were selected from the road traffic accident liability certification and serious accident reports issued by the traffic police department, and 110 risk points and 218 triggering relationships were abstracted based on network theory analysis to establish a traffic accident risk network. Analyse and compare indicators such as network density and network diameter to reveal the overall nature of the traffic accident risk network. The key risk factors of the risk network are analysed and identified using node indicators such as degree and betweenness. The results show that most traffic accidents are triggered by human factors, among which the driver factor is the main factor. Speeding and improper emergency measures are the two most important factors that need to be controlled. Based on the results of this analysis, this article puts forward management suggestions to improve the level of traffic safety.
Research Progress on Safety Control of Surrounding Rock-Support System in Deep Buried Soft Rock Tunnels
Authors: Li Jianhe , You Wanmin , Wu Song , Li Jian , Han Jian
Published: April 2021

The deep-buried soft rock tunnel has large deformation degree and long duration, which makes the surrounding rock-support very difficult. How to formulate effective design countermeasures to control soft rock deformation is one of the important technical problems in the design and construction of deep-buried soft rock tunnels. There are three critical problems in the research of soft rock deformation control, i.e. the bearing mechanism of the surrounding rock-supporting system of the soft rock tunnel, the safety control indexes and control standards of the surrounding rock-supporting system, and the reasonable support timing and support rigidity. Remarkable achievements have been made in the deformation control of deep-buried soft rock tunnel by theoretical analysis, field tests and numerical simulation over the past decades. By summarizing the research progress related to these three critical problems, the form of surrounding rock pressure is discussed, and the safety control indexes and standards for surrounding rock-supporting system are established. It is believed that based on the load-bearing law of the surrounding rock-support system and its safety control standards, an in-depth study of the reasonable support timing and reasonable support rigidity of the surrounding rock under different geological conditions is the critical and difficult problem for the safety control of deep-buried soft rock tunnels.
Experimental Investigation on the Sand Deposit Foundation of an Immersed Tube Tunnel by Using a Sand Flow Model
Authors: Li Bo , Fang Yingguang , Li Wei
Published: April 2021

Sand flow is a mainstream construction method to treat the foundation of immersed tunnel. The characteristics of the sand deposit foundation, including its size and compactness, as well as fullness degree, are key indicators for estimating the effect of foundation treatment on the immersed tube tunnel. In this study, three series of model tests were conducted. The characteristics of fullness degree and compactness were elaborated. In addition, tunnel uplift and its prevention, the effect of surface roughness of tunnel on the compactness and size of sand deposit, and the effects of different injection sequences on the fullness degree were investigated. Valuable practical suggestions were drawn from the test results. First, the incidence of tunnel uplift can be avoided by monitoring the hydraulic pressure under the bottom of tunnel with water pressure gauges. Second, the surface roughness of tunnel should be decreased to allow for a sand deposit with a large radius and consequently enhance construction efficiency. Third, the difference in injection sequences barely influences the fullness degree of sand deposit; therefore, injection sequences can be flexibly designed to provide convenience for construction.
Nonlinear Numerical Analysis on Seismic Performance of New-type Outer Hoop Box Column Joints
Authors: Pan Xiuzhen , Dou Tong , Li Hao , Chen Shiwei
Published: April 2021

The connection between the upper and lower structure is the key to seismic design of RC frame-lightweight steel mixed structure. This paper proposes a new type of outer hoop box column joint for this kind of mixed structure, which aims to strengthen the connection between exiting and new building, reduce the stiffness mutation and facilitate construct. In order to study the seismic performance of the new type of joint, the ABAQUS finite element software was used to carry out the numerical analysis of the new type of joint under the action of low-cycle cyclic loading with a 1/2 scale model, and the factors that affect the seismic performance were discussed in-depth. The results show that the hoop effect of the outer hoop steel plate strengthens the restraint on the core area of the joint and its surrounding members, which causes the plastic hinge position of the concrete beam to move outward, effectively protects the core area of the joint, and is beneficial to the bearing capacity of the new joint. Appropriately increasing the axial compression ratio can increase the bearing capacity, initial stiffness and yield displacement of the new joints to a certain extent.
Analytical Solution for Monopile Supported Offshore Wind Turbines Considering Soil-Pile-Water Interaction
Authors: Wang Piguang , Chang Yifu , Zhao Mi , Xi Renqiang , Zhang Chao
Published: April 2021

Offshore wind turbines (OWTs) are dynamically sensitive systems and vulnerable to external excitations such as aerodynamic and hydrodynamic loadings. These loadings may lead to excessive oscillation for the support structure of OWTs. Therefore, it is essential to evaluate the natural frequencies of the system to keep them away from excitation frequencies of external vibration sources. This paper investigates the natural frequencies and seismic responses of the OWT system. The soil-structure interaction (SSI) is modelled by three coupled springs and fluid-structure interaction (FSI) is simulated by the added mass. Then a closed-form solution of the natural frequencies is derived to consider the variation of cross-section. Furtherly, seismic responses of the system are obtained by mode superposition method. Effects of SSI, substructure mass and axial loading are finally investigated. The results indicate that substructure mass can significantly decrease the frequencies of the structure while axial loading plays only a small part in the process. SSI has an important effect on the seismic responses of OWTs. It is essential to consider the cross-coupling spring to analyze the seismic responses for accuracy.
Numerical Analysis on the Effect of Vital Design Parameters on the Seismic Performance of Shear Walls with Horizontal Ring Connection
Authors: Zhou Jian , Zhang Tao , Li Liming , Guo Zhipeng , Shi Qiancheng
Published: April 2021

Prefabricated shear walls are currently widely applied in mid-to-high-rise structures. As a new type of structural form of assembled shear walls, the ring connection assembled concrete shear wall has clear mechanical mechanism, easy construction and better performance and other significant advantages, which are gradually being applied in actual engineering. However, few systematic studies are carried on this new type of shear wall structure, and a complete theoretical system for guiding the design could not be given, especially in terms of mechanical mechanism and seismic performance, more detailed research work is needed. This paper uses numerical simulation as the main method to study the influence of different design variables such as shear span ratio, buckle size, axial compression ratio on the mechanical properties of the connection area in shear wall and the overall seismic performance of the structure. In this way, the theoretical basis for further optimizing the structural performance of the shear wall connection with ring connection.
Comparative Study on Layout Scheme of High Head Diversion Power Station----Taking the Yamu River-I Hydropower Station as an Example
Authors: Pan Shaohong , Wu Yunen , Ding Fengfeng
Published: April 2021

The small hydropower stations on most tributaries in the middle reaches of Salween River are mostly high-head diversion hydropower stations, and the choice of hub arrangement scheme is an important content of the preliminary construction project. Taking Yamu River-I Hydropower Station as an example, this paper compares and analyzes the layout scheme of the main hub of the project from the aspects of dam site, dam type, regulation scheme, diversion route and site selection, and summarizes the optimization ideas and characteristics of the layout scheme of the main hub of the project, so as to be helpful for the preliminary design of similar hydropower stations.
Influence of Seawards Water and Sediment Conditions on the Turbidity Maximum Zone in Yangtze Estuary
Authors: Huang Libing , Zheng Baoqiang
Published: April 2021

On the combined influence of runoff and tide, seawards sediment forms the turbidity maximum zone (TMZ) nearby the sandbar of Yangtze estuary. The water and sediment transport of the sandbar has important theoretical and practical significance for ecosystem, waterway regulation, and so on. According to the situation of seawards water and sediment variation, and based on the ECOMSED simulation of flow and suspended sediment dynamic process, the relation of the seawards water and sediment and the TMZ, and the law of water and sediment motion after the Three Gorges Project are discussed. It enhances the comprehension of suspended sediment concentration (SSC) variation law of the TMZ always seawards discharge. As the lower seawards sediment concentration, the SSC of the TMZ center is gradually decreasing with the increasing discharge. As the sediment concentration is higher than some critical value, the SSC of the TMZ center is gradually increasing with the increasing discharge.