bluuebunny/crossref_metadata_2025 huggingface dataset:
Characteristics of Chemical Quality Reduction in Fresh Baung Fish (Mystus nemurus) with Different Methods of Death at Room Temperature
Authors: Karnila R. , Edison  , Fadhlami P. I.
Published: April 2021

Baung fish is a fishery commodity that contains high water content so it is easy to decompose (high perisable product). The purpose of this study was (1) to examine the freshness level of the baung fish, (2) pH level, Total Volatile Base (TVB), and glycogen of the baung fish by different mortality death. This research was conducted using an experimental method, consisting of two steps: (1) preparation and observation of freshness level of fresh baungfish, (2) analysis of chemical reduction of fresh baungfish including pH, TVB, and glycogen content. The treatments of the research were (1) the baungfish died by itself (A1), (2) the fish were stabbed out the medulla oblongata (A2). Chemical reduction of fresh baung fish at room temperature was measured every 4 hours for 12 hours with parameters such as pH, TVB, and glycogen content. The data were analysed descriptively. The results of this research showed that the characteristics of fresh baung fish were move actively, healthy, difficult to catch, the opening and closing movements of the operculum were normal, and normal skin clour (not pale). The results of the chemical reduction test revealed that pH were 6.5 ± 0.05 at 0 hours to 7.0 ± 0.20 at 12 hours for treatment A1, while for treatment A2 was 6.3 ± 0.1 at 0 hours to 6, 6 ± 0.1 at 12 hours. The TVB test results showed 0.14 ± 0.04 at 0 hours to 31.32 ± 0.09 at 12 hours for A1 treatment. Whereas A2 treatment was 0.10 ± 0.03 at 0 hours to 26.30 ± 1.87 at 12 hours. Furthermore, glycogen levels showed at 6.67% ± 0.03 at 0 hours to 0.35% ± 0.13 at 12 hours for A1 treatment. While the A2 treatment was 7.69% ± 0.12 at 0 hours to 1.15% ± 0.26 at 12 hours.
Characteristic of Nano-Calcium Bone from a Different Species of Catfish (Pangasius hypophthalmus, Clarias batrachus, Hemibagrus nemurus and Paraplotosus albilabris)
Authors: Sumarto  , Desmelati  , Sari N I , Angraini R M , Arieska L
Published: April 2021

Fishbone contains mineral components that can potentially be exploited to improve the nutrition of food products. This research was aimed to determine the quality characteristics of nano-calcium bone from a different species of catfish. This research used an experimental method by producing nano-calcium from other types of catfish (Pangasius hypophthalmus, Clarias batrachus, Hemibagrus nemurus, and Paraplotosus albilabris) using 1M NaOH. The production of nano-calcium from the bone of different species of catfish produce a white fishbone nano-calcium color, with the whiteness degree of 90.7% (P.hypophthalmus); 88.9% (C.batrachus), 89.1% (H.nemurus), and 88.4% (P.albilabris). The moisture content in catfish bone nano-calcium in P.hypophthalmus. C.batrachus. H.nemurus, and P.albilabris was relatively similar, Ranging from 5.71%-6.12%. Calcium content of catfish bone nano-calcium very high in P.hypophthalmus, C.batrachus, H.nemurus, and P.albilabris were 87.4%; 89.6%; 89.1%, and 86.1% respectively. While the phosphorus level in P.hypopthalmus fishbone was 11.2%. C.batrachus fishbone was 9.4%, H.nemurus fishbone was 9.8%, and P.albilabris fishbone was 12.7%. The particle size of nano-calcium in P. hypophthalmus fishbone was 248-672 nm, in H.nemurus fishbone 206-594 nm, and nano-calcium in C.batrachus fishbone was 135-573 nm.
Community readiness model for social forestry in Central Sulawesi, Indonesia
Authors: Umar S , Yodo S , Narawi M , Pribadi H , Samudin S , Prianto W
Published: April 2021

Community Readiness Model (CRM) is a research method widely used in the field of public health. The purpose of the paper therefore is to review the implementation of CRM in Social Forestry field (SF) of Central Sulawesi Province, Indonesia by considering the unique intersections between the two concepts. Qualitative Systematic Review was used in this study involving 169 documents obtained through the search of electronic sources. The main result was on combining the dimensions of both the CRM and SF to produce an integration model which intersects and transforms social values, culture, traditions, and behaviour. Social innovation involving network, strategy, solidarity, and collective identity was intersected between the dimensions of CRM and SF to consider the intrinsic values of the village community. These four components were specifically related to partnership, governance, resilience, community and policymaker, livelihood, social cohesion, and integration. The application of CRM to Social Forestry in Central Sulawesi has the ability to optimize local wisdom teaching about the change and harmony of life to provide a balance between humans and nature.
Spatial distribution of water quality in Belawan River, North Sumatra
Authors: Mirandha A , Irvan  , Wahyuningsih H
Published: April 2021

Belawan river is one of the rivers in North Sumatera Province. Belawan river which crosses Deli Serdang District and Medan City is used for the activities of plantation, agriculture, livestock, sand mining, a place for bathing and washing as well as serving as a lavatory, hospital, hotel, settlements, and industry. Utilization of the river as a wastewater disposal site can cause a decrease in the quality of river water. The purpose of this research was to analyze the Belawan river water quality spatially. Water sampling was taken at nine points which included three upstream segment points in Deli Serdang District, three middle segment points in Deli Serdang District and Medan City, and three downstream segment points in Deli Serdang District. Based on the results of the research it can be concluded that the value of Biological Oxygen Demand (BOD) and Chemical Oxygen Demand (COD) at several monitoring points in Belawan river has exceeded the water quality standard limits of class I Government Regulation of Republic of Indonesia Number 82 the year 2001 and North Sumatera Governor Regulation Number 21 the year 2006.
Impact of different salt levels on the seedling growth and root development of Bruguiera sexangula for the regeneration of mangroves
Authors: Basyuni M , Manalu N B , Yunasfi
Published: April 2021

At present mangrove forests have been degraded in North Sumatra, Indonesia. It is therefore the rehabilitation efforts are needed to betterment of mangrove forests. Salinity influences plant growth and development because salinity conditions that are not suitable leading to plant growth and development. This research aims to study the impact of difference salinity concentration on the growth and development of Bruguiera sexangula seedlings. The study was performed using five treatments levels of salinity, namely 0%, 0.5%, 1.5%, 2% and 3%, respectively with ten replications for five months in the greenhouse of Faculty of Agriculture, Universitas Sumatera Utara. There were differences in the growth response of B. sexangula to variations in salinity concentrations. These results indicated that the best growth and development of B. sexangula seedlings at 0.5% salinity concentration of with six best parameters, namely superior height, diameter, number of leaves, number of lateral roots, main root diameter and lateral root diameter.
Species composition and carbon stock estimation in Pulau Sembilan secondary mangrove forests, North Sumatra, Indonesia
Authors: Basyuni M , Simanjutak E O
Published: April 2021

This study aimed to identify the species composition and measure the carbon stock estimation from the secondary mangrove forest. Analysis of vegetation (tree, sapling, and seedling) was carried out at Pulau Sembilan, Langkat, North Sumatra, Indonesia. The development of the seedlings, saplings, and trees was determined from four transect lines. Each transect had 100 m length. Each measured plot of total four transects contained 30 plots. The result showed that Rhizophora apiculata predominated vegetation types of seedlings, saplings, and trees in the mangrove forest, with the highest importance value index (116.13%). On the other hand, Bruguiera parviflora had the highest IVI (71.37%) of saplings, while at seedlings and tree levels were dominated by R. apiculata with IVI, 65.30%, and 75.48%, respectively. The diversity index of Shannon-Weiner ranged 1.11-1.49 at the secondary mangrove forest. In secondary mangrove forests had total biomass of trees at 51,589.83 kg/ha with a carbon potential of 23.73 tons/ha. This study provided a basis for rehabilitation, mangrove management and enrichment information in secondary mangrove forests.
Soil arthropod species and their abundance in different chili management practices in freshwater swamps of South Sumatra, Indonesia
Authors: Herlinda S , Fadli R , Hasbi  , Irsan C , Setiawan A , Elfita  , Verawaty M , Suwandi S , Suparman  , Karenina T
Published: April 2021

The chili management practices can influence the predatory arthropod community. This study aimed to identify soil arthropod species and examine their abundance in different chili management practices in freshwater swamps of South Sumatra. The survey was conducted in three types of chili field, first without mulch and synthetic insecticides, and by fertilizing using manure (EF). The Conventional 1 (C-1) used plastic mulch, synthetic fertilizers, and synthetic insecticides. The Conventional 2 (C-2) used insecticides and synthetic fertilizers but without mulch. The total of all soil arthropod species was found in the different chili management practices of 24 species originating from Insecta, Arachnida, and Diplopoda. The highest number of soil arthropod species was found in EF, while the least number was found in C-1. This survey found species of predatory mites (Macrocheles dispar), spiders (Pardosa birmanica), and predatory insects (Coccinella transversalis) and other important predators such as Pheropsophus occipitalis and Pardosa pseudoannulata. The abundance of soil arthropods either predators, herbivores or neutral insects was the highest in EF, while the lowest one was in the C-1. Overall, different chili management practices affected the number of species and abundance of soil arthropods; the environmentally friendly plot has the highest number of species and the largest abundance.
Analysis of soil physical properties and infiltration rates for various landuses at Gunung Dahu Research Forest, Bogor District, West Java Province
Authors: Saputra N E , Wibowo C , Lisnawati Y
Published: April 2021

Assessment of the ability of the soil to absorb water can be known from the value of the infiltration rate. This study was conducted to examine the physical properties of soils and infiltration rates, analyze the relationship between physical properties of soils and their infiltration rates and determine the best infiltration models for various land uses. The data is processed using the Horton and Kostiakov infiltration model. Correlation analysis and R tests were performed to compare the field infiltration rate with the model prediction results. The results showed that the physical properties and infiltration capacity in the three land uses differed significantly on several parameters of physical properties such as drainage pore, permeability and infiltration with sequential values in the stands of S. leprosula, S. selanica and tourism objects were 3.21%, 2.29%, 3.51% for the parameters of fast drainage pores and 7.84%, 8.67%, 7.49% for slow drainage pore. Whereas the average permeability values are 1.37 cm / hour, 2.13 cm / hour, 3.39 cm / hour. Based on the results of field infiltration measurements, it was found that the S. selanica stands had the highest infiltration rate with a value of 15.5 cm / hour. The results of the correlation test and regression test between the field infiltration rate and the Horton infiltration model rate were not significantly different so that the Horton infiltration model can be used for the infiltration rate of soils in the Gunung Dahu Research Forest.
Physicochemical characteristics of donuts from composite flour (modified sukun, sweet poultry, mocaf, saga seeds)
Authors: Sanjaya N , Nurminah M , Karo-Karo T
Published: April 2021

This research aims to determine the composite flour formulation from modified breadfruit flour, purple sweet potato flour, mocaf and saga seed flour in making good quality donuts. The analysis was carried out using a non factorial complete randomized design, donut with composite flour formulation (modified breadfruit flour, purple sweet potato flour, mocaf and saga seed flour) (P): 10%: 40%: 50%: 0%, 15%: 35%: 45%: 5%, 20 %: 30%: 40%: 10%, 25%: 25%: 35%: 15%, 100% purple sweet potato flour, 100% mocaf, 100% modified breadfruit flour, and 100% wheat flour had a very significant influence on protein content, crude fiber content, fat content, specific volume and L. The final results of the study showed that the formulation of composite flour (modified breadfruit) purple sweet potato, mocaf and saga seeds) (25%: 25%: 35%: 15%) produce the best quality donuts.
Physicochemical characteristics of crackers from composite flour (modified sukun, sweet powder purple, mocaf, and saga seeds)
Authors: Khairatika I , Nurminah M , Lubis Z
Published: April 2021

Crackers are one type of processed food that is very popular with the community. Crackers are usually made from wheat flour and have a layered, dry, and usually salty structure. Among this type of pastry community is much in demand as a snack when relaxed. However, due to the increasing value of imported flour in Indonesia, these crackers can be made using composite flour such as breadfruit flour, purple sweet potato flour, mocaf, and saga seed flour which are found in Indonesia. This research consisted of 8 treatments with the best modified breadfruit flour ratio: purple sweet potato flour: mocaf: saga seed flour ie P1 = 10: 25: 65: 0, P2 = 15: 20: 60: 5, P3 = 20: 15: 55:10, P4 = 25: 10: 50: 15, P5 = 100% modified breadfruit flour, P6 = 100% Mocaf, P7 = Purple sweet potato flour, P8 = 100% flour. The results of the study had a significantly different effect (P <0.01) on the value of specific volume, ash content, fat content, fiber content, and protein content. But no significant effect on the value of L *, a *, b *, oHue, carbohydrate content, color, aroma, texture, taste and general acceptance of crackers produced. And based on the De Garmo test with organoleptic parameters of color, aroma, taste, and texture, general acceptance, moisture content, fat, fiber, protein, and ash content, crackers with treatment P4 = P4 = 25: 10: 50: 15 are the best crackers.
Predicted of a heat shock cognate 70 kDa protein by PHYRE2 and SWISS-MODEL software from Elaeis guineensis and E. oleifera
Authors: Hayati R. , Basyuni M , Lisnawita  , Munir E
Published: April 2021

Protein modeling was obtained from Elaeis guineensis and E. oleifera. The identification of heat shock cognate70 kDaboth very similar to coverage 90% analyzed by SWISS-MODEL. In addition, the data from similarity, identity, range, and Q-mean were distinct. According to the PHYRE2 analysis, we observed the longest residue presenting in E. guineensis (15-348). Wherein the 3D-ligand site prediction confirms that many amino acids were found (GLY, THR, TYR, LYS, GLU, ARG, and SER). Interestingly, the heat shock cognate 70 kDa protein in E. oleifera has a slight residue (15-18), and also have been three amino acids (GLY, THR, TYR). Appropriately, the heat shock cognate-like protein involved in different species, likewise playing a distinct response to kind the defense. The different homology images and templates were identified as different binding site predictions. These models can be used for supporting the E. guineensis and E. oleifera proteins modeling, mainly in the molecular study.
The chemical changes in the total antioxidant status and biological activity of GSTP1 polymorphism on nasopharyngeal carcinoma patients
Authors: Farhat F , Sari M I , Chrestella J , Syari R P
Published: April 2021

Oxidative stress is associated with cancer, including NPC, which is developed by the relation of genetic alteration, EBV infection, and environmental risk. Ile/Val genotype of GSTP1 polymorphism decrease enzyme functions and result in lower total antioxidant status. This study aimed to identify the association of GSTP1 polymorphism and the TAS level. This was a cross-sectional design study. There were 29 NPC patients with their blood as the samples of the study. Blood as the samples for identifying GSTP1 polymorphism by PCR-RFLP-electrophoresis method and measurement of TAS using the ELISA method. There were 21 (72.4%) NPC patients with Ile/Val polymorphism and lower TAS. We found there was no significant association of GSTP1 polymorphism and TAS. Future research with larger samples and adding data about environmental risk such as smoking, alcohol consumption, and toxic substances exposure or multivitamin consumption of the patients can reveal more definitive results. The study may be used as references for determining antioxidant therapy in NPC as well as prevention. The identifying genetic risk factor may help the prevention of NPC.
HSP70 (heat shock protein 70) expression and antioxidant as a protective againts oxidative stress triggered by sub-maximal physical activity
Authors: Harahap N S , Amelia R , Sibuea A , Manalu N , Novita N
Published: April 2021

Sub-maximal physical activity will interfere with the ROS and antioxidants balance, so oxidative stress occurs. Oxidative stress can induce increased expression of HSP70 in cells to produce a cytoprotective effect. Red dragon fruit in biological systems can neutralize free radicals, because it contains flavonoid compounds and polyphenols. There were 20 participants, male, athletes, non-smokers and 2 weeks before and during the study, no consumption of supplements and antioxidants. Participants were randomly divided into 2 teams. Team A had sub-maximal activity and no red dragon fruit given. Team B had activity sub-maximal and was given red dragon fruit juice. Study found that HSP70 expression was lower in the team B than in team A. There was significancy difference between team A and team B in expression of HSP70. We concluded that, HSP70 expression and antioxidants can be the protective function against oxidative stress triggered by sub-maximal physical activity.
Application of ABAQUS on the Research of the Thermal Field of SRC Columns
Authors: Zhang Qingwen
Published: April 2021

According to the basic principles of heat transfer, the thermal field of SRC columns under fire is analyzed by finite element analysis software ABAQUS and the calculated results agree well with experimental data at home and abroad. On this base, the influence of parameters of sectional dimensions, length-to-width ratio of the section, steel ratio and reinforcement ratio to the distributing circumstance of thermal field of SRC columns are analyzed. The results show that parameters of sectional dimensions and length-to-width ratio are the most important factors affecting the distributing circumstance of thermal field of SRC columns. The larger the parameters of sectional dimensions, the lower the component temperature. The greater the length-to-width ratio, the greater the component temperature is. Steel ratio and reinforcement ratio have almost no effect on the distributing circumstance of thermal field of SRC columns. The achievements make it possible to study further the mechanical performance of SRC columns at high temperature.
Analysis on Blasting Effect of Parallel Cut with Empty Hole in Tunnel Construction
Authors: Lai Zhenyu
Published: April 2021

Establishing a calculation model for parallel cut blasting effect has certain practical significance for guiding tunnel blasting construction. A calculation model of cutting blasting effect is established based on the theoretical analysis in this paper. Under certain conditions, the quantitative relationship between the cutting efficiency and the hole diameter, the depth of the cut hole and the hole distance between the cut hole and the empty hole is obtained. The calculation results of the model are consistent with the results of a pure cutting test, which shows that the calculation model is reasonable.
Stress Analysis of Screw-Bored Compaction Cast-in-Place Piles
Authors: Zheng Xianchao , Chen Xiaoxia , Zhang Jiaolei
Published: April 2021

Based on the current research status of screw-bored compaction cast-in-place piles (screw piles for short) and using ANSYS finite element software, in this research, a simulation analysis of the pile axial force and the side friction was conducted for three types of screw piles with different screw length ratios under vertical loading. The modeling analysis results were compared with the engineering data from a practical project in Anyang City, Henan Province, and the finite element model was validated. This research determined the effects of the screw length ratios on the pile axial force and the side friction and provided a theoretical foundation for the engineering design of a screw pile.
Bearing Capability for Mirco-Pile with Concrete-Filled Steel Tubular Reinforced Building Foundation
Authors: Shen Yongkang , Zhong Weiqiu , Qu Guotong , Li Wuxu
Published: April 2021

In general, the bearing capability is strength capability for mirco-pile. The stability bearing capability for mirco-pile with concrete-filled steel tubular becomes important in reinforced building foundation. The theory of buckling stability is applied to study the bearing capability of mirco-pile. According to the character of concrete filled steel tubular, the Euler force and the friction between pile and soil are combined for the buckling bearing capability of mirco-pile with concrete-filled steel tubular. The equation of mirco-pile with concrete-filled steel tubular is confirmed by some test data and numerical simulation. The slenderness ratio and material strength took great effects on the bearing capability of mirco-pile with concrete filled steel tubular. The equation on bearing capability mirco-pile with concrete filled steel tubular is applied for reinforce building foundation and referred to other application of concrete filled steel tubular.
Research on FBG Technology Applied in Highway Soft Foundation Pore Pressure Monitoring
Authors: Liu Youping
Published: April 2021

The pore water pressure monitoring of soft ground pavement is one of the important technical links in highway construction monitoring. The use of traditional electrical measuring instruments to monitor pore water pressure has disadvantages such as low degree of automation, non-real-time data transmission, and high manual monitoring costs. However, fiber grating monitoring technology has developed rapidly due to its advantages of stable data transmission, convenient collection, and dynamic monitoring. . Therefore, relying on the soft foundation pore water pressure monitoring project of Jiujiang Ring Expressway, the monitoring principle of the fiber grating seepage pressure sensor and the buried installation technology in the soft foundation are introduced. Through the long-term monitoring practice on the construction site, it is confirmed that the optical fiber monitoring system is applied to the soft foundation. The stability of base pore water pressure monitoring provides a reference for similar monitoring projects and engineering construction.
Research and Development of Railway Alignment Design System Using FreeCAD Software
Authors: Wang Huansong , Lu Wenlong , Shi Ruichang , Yu Shengli , Wu Fadong
Published: April 2021

This paper explores the functional modules of railway alignment design in the open source FreeCAD software, and makes a foundation development for other railway majors in the open source software. The interactive interface is designed by pyside. The geometric elements of the railway alignment, the coordinates of the main point (ZH, HY, YH, HZ, QZ) and the elevation of end or start point in vertical curve are calculated according to the intersection data, so as to realize the design of the horizontal and vertical section for the alignment. OCC interface is accessed through part module to realize the synthesis of railway baseline. Comparing the baseline generated by FreeCAD with the pile-by-pile coordinates of a project bid section, the coordinate error is less than millimeters, which can well meet the needs of railway construction.
Study on the Influence of Excitation in Sliding Construction of Long Span Steel Structure
Authors: Zhou Qinghui , Zhang Chenlong , Xiao Long , Zhang Xiwang , Xie Yidong
Published: April 2021

There is a safety risk on sliding construction because of the unstable state of large-span steel structure. The core technology of sliding construction is synchronous control. In this paper, a large-span steel structure sliding construction is taken as an example. The span reaches 202.2 m, which is the first case in China. Based on the theoretical analysis of the sliding process, the mathematical sliding model is established, and the main parameters are analyzed. The displacement and synchronization error under the external exciting force are calculated. The sliding motion, mechanical properties are studied. It also provides measures to improve synchronization performance. The result has proved that the scheme effectively guarantees the construction safety and quality. So it is also a reference for the design and development of the synchronous control.
Research on Safety Management of Construction Site Based on BIM
Authors: Yu Zhihong
Published: April 2021

With the development of social economy at this stage, the construction industry has also increased certain progress, in the construction engineering construction, construction safety management is very important. Compared with the traditional construction safety management, BIM Technology can find the hidden danger in the construction project in time, and check the potential safety hazard in time, so as to ensure the safety of construction. In this paper, BIM Technology is used to manage the safety management of construction site in time and space, and the fall protection control based on BIM is studied. Hope to be able to provide a certain reference and reference for future related project safety management, so as to ensure that the overall construction safety management ability and quality of the construction project can meet the requirements to the greatest extent.
Experimental Research on the Vibration Absorption Performance of Medium Damping Fasteners in Metro Shield Tunnel
Authors: Zeng Zhiping , Guo Wuji , Ying Huatuo , Huang Xiangdong , Wu Zhipeng
Published: April 2021

Medium damping fasteners have the advantages of low cost, easy maintenance, and convenient in gauge adjustment, etc., which are gradually and widely used in metro construction. In order to study the performance of medium damping fasteners in a driving environment, we performed measurement on site about the vertical and lateral displacement of the rail, as well as the vertical acceleration of the rail and the tunnel wall on a straight and curved metro cross-section with medium damping fasteners. By comparing with the results of ordinary fasteners, it can be seen that: (1) The medium damping fastener has a vibration reduction effect on the vertical acceleration level of the tunnel wall in the frequency range of 6.3∼31.5Hz and 50∼80Hz; moreover, it has a vibration reduction effect on the lateral acceleration of the tunnel wall in the frequency range of 5∼31.5 Hz and 50∼80 Hz. (2) The vertical and lateral displacement of the rail and the gauge change with the medium damping fasteners are larger than those of the ordinary fasteners. (3) The maximum Z vibration level measured from the tunnel wall is most suitable for evaluating the source strength of the metro, wherein the source strength of this metro line is 88.42 dB.
Comparative Study between Chinese and British Design Codes of Cup-Lock Scaffolding System
Authors: Hao Jianbing , Qu Tianshi , Chang Peng , Bi Xuelin
Published: April 2021

A comparison study between Chinese and British codes for cup-lock scaffolding and formwork system were carried out. The analysis results show significant difference between these national codes regarding falsework management and design methodologies. The difference in the management is mainly focusing on whether the execution should be performed by main contractors or the falsework specialists. The difference in design, however, is the design methodologies of concrete lateral pressure on formwork, wind load and the capacity of the cup lock pipes. Mix use of different design codes can cause unreliable change of system safety margin and negative impact to the project cost. A case study is also provided to show the difference in the safety margin which can leads to opposite results if different codes are adopted in the projects.
Investigation of Structural Stress Monitoring System on Excavator under Impact Loads
Authors: Peng Liang , Chen Zhenlei , Shi Yongkang , Li Ganggang , Zheng Daiwei
Published: April 2021

Displacement and pressure sensors were used to measure the displacement and pressure variations of the hydraulic cylinders in an excavator under impact loads. Taking the measured cylinder displacement as a driven boundary condition, the kinematics simulation is completed in the LMS Virtual Lab. Taking the measured cylinder thrust and the simulation results of the kinematics as driven boundary conditions, the dynamic simulation of the excavator is carried out. The CAE dynamic stress analysis of the boom and arm of the excavator is performed using ABAQUS inertial release approach under the loads on the sub-structure obtained from the above multi-body dynamic simulation and the measured data, it provides a reference for the material selection of each part of excavator boom. The good agreement between the analytical and testing results demonstrates that the present method is accurate, efficient, cost effective, and able to monitor the stress status and access the health of an excavator instead of using field testing techniques.
Numerical Simulation of Borehole Slotter Layout Optimization
Authors: Li Yong-song , Ai Kai , Niu Lin-xin , Liu Wei
Published: April 2021

This paper briefs the basic principle, current methods and test process for measuring in-situ stress by the borehole slotter method. Studies are carried out to optimize the slot’s cutting depth and layout by means of 3D numerical simulation. Such simulation results show that when the original stress field is parallel to the slot, the required cutting depth to fully release the stress on both sides of the slot reaches its peak (16 mm). In order to avoid interaction between slots and enhance reliability, only one slot is arranged at a given drilling depth and the space between slots should generally be greater than 200 mm. Based on such results, the in-situ stress measurement was conducted by means of the borehole slotter method in an underground laboratory in Jinping. The tested rock mass is in stress concentration area in a tunnel face, and the acquired vertical component of the stress is found greater than the self-weight of the overlying rock mass. This field test shows that such test rock mass is under extremely high stress condition, which is in compliance with disked rock cores discovered during tunneling.
Experimental Study on Critical Moisture Content of Octadecylamine Modified Expansive Soil
Authors: Ao Weichao , Wang Maosheng , Liu Jiaming , Li Jie , 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 and initial moisture content were configured. The dripping water penetration time method was used to determine the water repellency grade of the modified expansive soil, and the critical moisture content test of the modified expansive soil was carried out to analyze the relationship between different octadecylamine content and the initial moisture content of the expansive soil. The results show that with the increase of the initial moisture content, the water repellency of the modified expansive soil first increases and then decreases. When the octadecylamine content is 0.8%, the limit moisture content is 33.33%, and the peak moisture content is 29.51%. The bottom water content is 0%, and its interval value is 3.78 times larger than when the octadecylamine content is 0.2%.he above research results can provide a test basis for the engineering application of modified expansive soils.
Influence of Hollow Effect on PPV of Wall Rock under Blasting Load
Authors: Cai Jun , Qiu Xiuli , Su Ying
Published: April 2021

The purpose of writing this thesis is to solve the problem that the hollow effect of blasting construction affects the PPV of tunnel wall rock. Based on the law of energy attenuation and seismic wave propagation, the calculation equation of PPV of wall rock in excavation area and no-excavation area under blasting load is derived, and the variation law of PPV of wall rock under different loads is calculated by FLAC3D software. The results show that: (1) The accuracy of the calculation equation is verified by the calculation results of the software; the error between those is less than 6%; (2) In the range of twice the distance from the Heading Face, the hollow effect of wall rock is directly proportional to the load value; (3) The blasting load of 0.8MPa makes the maximum void effect concentrated in the wall rock 8m away from the face. The difference of PPV between the excavated area and the uncut area caused by void effect is 2.23 cm/s, and the quotient is 1.21 times.
A Study on Constitutive Model of the Cohesive Soil Considering Soil-Structure Interactions
Authors: Wang Haibo , Cheng Yongfeng , Lu Zhicheng , Zhu Zhubing , Xue Yaodong , Zhang Shujun
Published: April 2021

Transformer is key equipment in the power transmission and transformation system. When the seismic calculation is carried out, the foundation soil is generally considered to be absolutely rigid, and the bottom of the structure is considered as the fixed end, the soil-structure interaction is ignored. This paper is aimed to study the soil-structure interaction’s impact on the seismic performance of the transformer and other power facilities by carrying out cyclic shear test on cohesive soil, simulating the dynamic response of clay soil under the seismic load, and get the nonlinear dynamic characteristics parameters of the soil in the loading process of seismic cycles. On the basis of the study, the fitting equation of the dynamic shear modulus and damping ratio of the soil is put forward through analyzing the cohesive soil dynamic hysteresis constitutive model.
Mechanical Modeling of Progressive Failure of Tieshansi Slope
Authors: Kou Huanjia , Lu Yingfa , Liu Gan , Huang Wansong
Published: April 2021

With the rapid development of china economy, the mining environment improvement is a hot research topic. The traditional unbalanced thrust method is generalized, the partial strength reduction method (PSRM), the perfect elasto-plastic model (PEPM) and the complete process constitutive model (CPCM) are employed; the progressive failure process of a slope is simulated by the proposed generalized slice method; the safety factor of the extended slice method is closely related to deformation of a slope, the characteristics of the critical stress state movement can also revealed by the proposed generalized slice method. Taking the Tieshansi slope of Huangshi City as an example, the evolution characteristics of the physical and mechanical variables in progressive failure process of the slope are revealed by the proposed generalized unbalanced thrust method with the two sorts numerical simulations (PSRM with PEPM and CPCM); the search results show that: The proposed generalized slice methods can describe the progressive failure process of the Tieshansi slope.
The Undrained Shear Strength Evaluation of Vinh Chau Clay in Vietnam Coast
Authors: Wang Weilong , Du Wenbo , Wang Kuanjun , Wang Zhenhong
Published: April 2021

In the foundation design, the geotechnical engineering parameters are of great importance. As a case study, the laboratory test results of two locations (Banpu and Lac Hoa) in Vinh Chau coast of Vietnam were analysed to acquire the accurate strength for clayey soil. Due to the sample disturbance, the undrained shear strength s
u from unconfined compression test are not so reliable, while su from direct quick shear tests (DSq) are more representative in Vinh Chau. A regression analysis between the DSq tests and soil depth had been carried out, good linear correlations are provided for all the three clayey layers in Banpu and Lac Hoa, the results are relatively similar for each clay layer, indicating a same sedimentary and stress history. Furthermore, the normalised undrained shear strengths s
u/σ
v0’ presented negative linear correlation of liquidity index, and the regression equations have been provided to rapid and cautious estimation of Vinh Chau clay in the future, using the liquidity index.
The Influence of Steel Bracing on the Stability of Foundation Pit Excavation under Dewatering Condition
Authors: Chen Xiaopeng , Lu Qingrui , Jiang Xiaoyi , Liu Jinling , Li Ping
Published: April 2021

In order to analyze the stability of under the condition of rainfall in tunnel excavation, a Phase of foundation pit in Fuchun River as the research object, according to the engineering quality condition and the excavation depth, using ABAQUS to the groundwater seepage of foundation pit, the process for the process of the change of the bearing capacity of foundation pit excavation, foundation pit precipitation is analyzed under the condition of using steel support and steel support in both cases the stability of foundation pit, to the wall and the interaction of surrounding soils including even the wall deformation of ground surface subsidence It is necessary to set steel support in large deformation area to provide certain basis for the smooth implementation of similar projects.
Effects of Mesoscopic Structure on Crack Resistance of Asphalt Mastic and Calibration of Contact Parameters
Authors: Zheng Chuanfeng , Teng Guocui , Chen Xiangyin , Li Xuan
Published: April 2021

This paper investigated the effects of mesoscopic structure on crack resistance of asphalt mastic basing on the bending failure simulation with discrete element method. A Dynamic Link Library wrote by C++ is proposed for the modelling process of particle filling. Response surface and variance analysis are used to calibrate mesoscopic mechanical parameters of contact model, determine the influence of different parameters on deformation in bending failure test and the relationship between the parameters is fitted by mathematical formula. The effects of air void content and fine aggregate surface texture on crack resistance of asphalt mastic at -10 °C were studied then. It was proved that the adhesive strength and bonding area between fine aggregates co-influence the ultimate bending failure load, and the contact stiffness influences the ultimate bending deflection. Mathematical correlation formula between the radius of binding area and the critical stress that satisfies the ultimate load of asphalt mastic beam can be fitted in same form. The flexural strain energy density of asphalt mastic is increased with the decrease of air void content. The results are of positive significance for improving the mechanical properties of asphalt road in cold regions.
Analysis of Modal Characteristics of Long-Span Suspension Bridges with Ruled Surface Spatial Cables
Authors: Zhang Honglei , Xu Wenping
Published: April 2021

In this paper, new concepts of single-leaf hyperboloid spatial cable suspension bridges and hyperbolic parabolic spatial cable suspension bridges are proposed. Combined with the 4000 m long-span Messina Strait Bridge, dynamic modal analyses of the spatial cable suspension bridges are carried out. The results show that the spatial suspension bridges have a torsional vibration mode appearing much later, a torsional-bending frequency ratio greatly improved, a critical wind speed for flutter greatly improved, and better wind stability, as compared with the parallel suspension bridge.
Layout and Optimization of the External Prestressing Tendons of Hybrid Beam Rigid Frame Bridges
Authors: Xu Guixiu , Zeng Minggen , Su Qingtian
Published: April 2021

External prestressing tendon systems can be set to alleviate the problem of excessive mid-span deflection of hybrid beam rigid frame bridges in the long-term use. Based on the Anhaiwan Bridge in Quanzhou of Fujian province, the effects of external prestressing tendons on reducing the deflection of the main span and improving the stress of concrete sections were studied by the shell- solid finite element models. Then the effects of the external prestressing tendons in the steel beams and the concrete beams were analyzed respectively. The effects of each prestressing tendon were further calculated. The final optimized layout was obtained by these studies, which can be used as a design reference for the external prestressed tendons of the hybrid beam rigid frame bridge. Finally, the deflection of the steel beam of the hybrid beam rigid frame bridge was analyzed under the impact of long-term effects such as shrinkage and creep. The comparative analysis of the different tensioning schemes for the external prestress tendons was carried out in order to provide a reference for the operation and maintenance management of the bridges.
Abrasion Resistance and Rutting Resistance of Micro-Surfacing with Crumb Rubber of Dry Process
Authors: Ye Yali , Hao Yan , Zhuang Chuanyi
Published: April 2021

In order to improve the common micro-surfacing is easy to loose and fall off, and improve the wear-resistance and anti-rutting performance of pavement, this paper uses waste rubber powder as the filler of micro-surfacing mixture, and adopts the method of dry adding. The test of micro-surfacing with crumb rubber of dry process based on APA test was carried out at 40 °C without water. Asphalt pavement analyzer shows that the micro-surfacing with crumb rubber of dry process has better wear-resisting and anti- rutting performance.
The Deterioration Laws of Flexible Base Asphalt Pavement Performance under 1/3 Scale Accelerated Loading Test
Authors: Zhuang Chuanyi , Zhao Shuqian , Wang Baoqun
Published: April 2021

To study the fatigue characteristics and the deterioration laws of asphalt layer under the repeated action of wheel loading, by using 1/3 proportional scale accelerated loading equipment to test the structure of graded crushed stone base asphalt pavement that was paved, tracking, monitoring and collecting the bottom strain of asphalt layer with different wheel loading times. The results show that the bottom strain of asphalt layer undergoes a change course of first compression, then tension and finally stabilization in the process of driving wheel load rolling. Under the repeated rolling action of wheel load, the change of bottom strain of asphalt layer is basically the same as that of temperature. When the asphalt layer is damaged, the bottom tensile strain curve deviates from the temperature curve with the wheel load times. The change of asphalt bottom strain and pavement temperature slope are taken as the basis to judge whether the asphalt bottom cracks or not, which is a beneficial supplement to the long-term performance observation of asphalt pavement.
Seismic Vulnerability Analysis of Isolation Bearing for Curved Continuous Girder Bridge
Authors: Huang Bowen , Li Zhengying , Wu Peitao
Published: April 2021

Based on a curved continuous girder bridge project, this thesis employed the seismic vulnerability method to analyze the isolation bearings which were usually considered as the fragile member of bridge. Laminates rubber bearing (LNB) was selected for analysis. The mechanical model and damage index are determined. The vulnerability curve of the bearings could be formed with the traditional reliability method based on logarithm linear regression analysis. Determined the mechanical model and damage index of the bearing, and the nonlinear dynamic analysis model of the bridge is established. Selected ten records of earthquake and amplitude modulated according to the requirements of incremental dynamic analysis method. Then, respectively formed the bridge - ground motion random sample with the bridge random sampleThe analysis results indicated that the position of isolation bearings and the direction of seismic inputting had different level effect on damage probability of bearings.
Numerical Study on Thermal Insulation of a Roadway Tunnel at Southeast Edge of the Qinghai-Tibet Plateau
Authors: Yu Hong , Zhang Kun , Zhu Xiaoming , Tian Zhizhuo , Mu Yanhu , Bi Guiquan
Published: April 2021

Tunnels in seasonal frost regions are heavily affected by damage related to icing problem and cyclic freeze-thaw of surrounding rock. To mitigate frost related damage, thermal insulation is widely used at entrance and exit section of tunnels. In thermal insulation design, length of the insulated section and thickness of the thermal insulation layer (TIL) are two important parameters. In this study, a coupled mathematical model of heat and moisture transfer was built for tunnels in cold regions. Then, field observed air temperatures at entrance section of a roadway tunnel at Altun Mountain, southeast edge of the Qinghai-Tibet Plateau, were collected and analysed. Based on the mathematical model and field observed inside air temperatures, seasonal freeze-thaw of surrounding rocks of the tunnel entrance was numerically investigated with consideration of the thicknesses and thermal conductivities of insulation layer. The results showed that, within the tunnel, the air has its mean annual temperature increase and the its amplitude decrease with increase in the distance from the entrance. The significant variations mainly occurred within the section 375 m from the entrance. Without the TIL, the maximum seasonal freeze depth of surrounding rocks at the entrance can reach to 1.5 m. To ensure that the surrounding rocks do not experience freezing, the minimum thickness of the TIL with a thermal conductivity of 0.037 W/(m·°C) should be 7 cm. While when the thickness of the TIL is 5 cm, its thermal conductivity should be not greater than 0.014 W/(m·°C).
Research on Waterproof Performance of Prefabricated Utility Tunnel with Different Types of Joints
Authors: Li Liangcheng , Zhang Yongyong , Zhou Wenyan , Song Li , Li Yuankun
Published: April 2021

In the waterproof system of prefabricated utility tunnel, rubber gasket is usually used at the joint of adjacent pipes. The waterproofing effect of prefabricated utility tunnel joint is mostly judged by the field water injection test and the practical effect of former project. In this paper, the finite element software ANSYS is used to carry out the finite element simulation for three types of joint waterproofing of prefabricated utility tunnel. Considering the uneven settlement of utility tunnel foundation, the influence of different staggered joint installation spacing on the waterproofing of the joints is analyzed. Thus, suggestions are provided for the selection of utility tunnel joint. For the prefabricated utility tunnel with side+end face and double-side joint waterproof type, the longitudinal distance between socket joints should be constrained within 3mm after the joint is installed. It is suggested that the end face+side joint waterproof type should be used for the collapsible foundation, and the longitudinal displacement of the control socket and socket should be less than 3mm. For non-collapsible and settled foundation, double-end joint waterproof type or side+end joint waterproof type can be selected.