bluuebunny/crossref_metadata_2025 huggingface dataset:
Value of domestic water economy and sustainability of regional cross water resources management
Authors: Burhanudin H , Akliyah L S , Kurniasari N
Published: March 2020

Water resources has economic, political, social and cultural values becomes a commodity desired by many people. On a cross-border administrative scale, the struggle for water can be a problem and is a source of conflict between communities, regions and even countries. A view of water resources as a public commodity that is not subject to prices is time to change especially for water use in a business. Water companies need to take into account the water value in relation to the cost of supply, in order to create sustainable water resources. The principle of paying users is applied to obtain compensation for the benefits received. Costs charged to water users need to be calculated through a reasonable payment mechanism in order to cover the costs of managing water resources that have been spent. The value of water benefits is the basis of the application of economic instruments to help the calculating process of water prices. This paper discusses the case of cross-regional water resource management in Indonesia Kuningan Regency – Cirebon City by emphasizing the value of water benefits as a basis for calculating water prices. Thus this paper will examine how the contribution of water resources if used for domestic water business (drinking water) based on the value of economic benefits and how the implications for the continuity of water resources management. Based on the results of the analysis it has been shown that if the raw water source is used for domestic water business, PDAM in Cirebon City is able to return 75% of the total cost of managing water resources that have been spent. Considering regulations where users of water sources outside the administrative boundaries are required to pay water prices, with this capability, water resources management across the Kuningan Regency -Cirebon City area has the opportunity to continue. On a global scale, the application of economic benefit values as a basis for calculating water prices can be used as a lesson for resolving cases of water resources conflict with characteristics similar to regions in Indonesia. By ensuring sustainable water resource management, at least the completion of cross-regional water resources in Indonesia can reduce the burden to resolve the problem of the water crisis in Southeast Asia.
The monozukuri concept as the right 5S implementation tool in Jakarta Vocational High Schools
Authors: Siahaan F S , Purba J , Buwono A , Ratih R , H Refendi
Published: March 2020

The concept of monozukuri as the implementation of 5S will have an impact on changes in the environment and work procedures towards a better direction. This development can also affect the mindset of ignorance of the environment itself. In general, the dream of every society expects a clean, neat, safe, comfortable environment to be maintained around. In achieving a clean and healthy environment, one of the patterns of approach that will be taken is to apply the 5S lifestyle that will improve the performance of the Vocational High School teachers in Jakarta. How does the monozukuri concept with the implementation of 5 S affect the performance of teachers in Vocational High Schools which aims to create a work environment that is free of obstacles and produces work effectiveness. The work method is carried out starting with creating a questionnaire Likert scale based on 5S implementation variables. Provisions on the judge’s approach to the number of respondents and then the pre-questionnaire test and the results will be tested for validity for the validity of each questionnaire as a parameter of actual data collection. The results of actual data collection will be tested for validity and then analyze the effect of dominant 5S / R by multiple regression methods.
Mathematical creative thinking ability in middle school students’
Authors: Sahliawati M , Nurlaelah E
Published: March 2020

The mathematical creative thinking ability in this study is the ability to think which involves elements of fluency, flexibility, originality, or elaboration, in the process of solving mathematical problems. This study aims at determining the mathematical creative thinking ability of junior high school students in solving the problem of the plane figure. To do so, first, 28 students in the 7th grade (12-13- years-old) from a junior high school in Indonesia were given four plane figure problems. The problems were developed based on indicators of creative thinking ability. Then, three of the students were selected based on the prior mathematical ability to represent the creative thinking ability of all students. The interviews were conducted to confirm the students’ answers. Finally, the results of student answers were analyzed based on indicators of creative thinking ability. The results of the study show that overall students were able to make new problems from the information presented, although the solution they wrote has not been systematically structured. In this case, the most visible students’ creative thinking element is flexibility.
Mathematical reflective thinking strategy in problem-solving viewed by cognitive style
Authors: Salido A , Suryadi D , Dasari D , Muhafidin I
Published: March 2020

Mathematical reflective thinking is a mathematical thinking activity involving the persistent consideration process of the use of knowledge and decision making in solving a problem. This study aims to describe mathematical reflective thinking strategy of students based on impulsive and reflective cognitive styles in solving the mathematical problems. To do so, first, we developed three tasks about the linear programming problems. Next, 35 students of senior high school in the 11th grade (16-17 years-old), were given tasks and continued with the giving one set of Familiar Figures Figure Test (MFFT). Then four students were selected as representatives of the other students. In-depth interviews were conducted with students to confirm the findings of the task’s answers. Finally, the data were analyzed to explain the mathematical reflective thinking strategy of students based on cognitive styles. We found that students with impulsive cognitive styles have a tendency to think reflectively on the stage of understanding and reflection, using inefficient strategies, not completing answers, and give up easily in the face of a difficult task. Whereas the students with reflective cognitive style have a tendency to think reflectively on the stage of reflection and critical reflection, using expert strategies, concluding answers, and solving difficult problems in accordance with logic; and trial and error.
Mathematical connection ability in 7th grade students viewed from self-regulated learning
Authors: Putri E R , Budiyono B , Indriati D
Published: March 2020

The purpose of this research is to determine which mathematical connection ability is better; students with high, medium or low self-regulated learning. This research was descriptive quantitative research. The instruments used in this research were questionnaire of self-regulated learning and written test of mathematical connection ability. The research samples consisted of 186 students who were studying at a state Junior High School in Sukoharjo Regency, Indonesia, with heterogeneous abilities. The data analysis technique used was one-way Anova with unbalanced cell and post hoc test using the Scheffe method. The results show that students with high self-regulated learning have better mathematical connection ability than students with medium and low self-regulated learning. Students with medium self-regulated learning have better mathematical connections ability than students with low self-regulated learning. In order to connect to each mathematical problem, students must first remember the problem, while to understand the problem, students must be able to make connections with topics related to the problem so that students’ efforts in finding solutions to mathematical problems are through self-regulated learning activities. When students have self-regulated learning, they will significantly improve their mathematical connection ability.
Analysis of mathematical creativity in the field of geometry in junior high school students
Authors: Permatasari S D A , Budiyono B , Pratiwi H
Published: March 2020

Nowadays, world civilization has entered the 21st century. One of the challenges of education in the 21st century is the development of human resources that have mathematical creativity. With mathematical creativity, students are trained to solve problems related to mathematics, students can facilitate their abilities, discuss various ways to find solutions, and make combinations of new knowledge or new problem solving techniques. This research has an aim to analyse mathematical creativity in the field of geometry in junior high school students in Surakarta. The research method used in this research is quantitative descriptive. The sample of this research is 56 students from 8th grade student of junior high school in Surakarta were taken by random sampling method that represent the population. The results of this research indicated that out of 56 students of junior high school in Surakarta have 2 students who are on level 3 of mathematical creativity, 17 students who are on level 2 of mathematical creativity, and 37 students who are on level 1 of mathematical creativity. These result can be used as preliminary data to determine the level of mathematical creativity students in Surakarta.
The effect of differentiated instruction on student mathematical communication ability
Authors: Nurasiah L , Priatna B A , Priatna N
Published: March 2020

This study aims to analyze: (a) mathematical communication ability of students before and after learning with Different Instruction; (b) difference between students’ mathematical communication ability using Differentiated Instruction and conventional learning. The research method used in this study is a quantitative research. 70 Junior High School students of the 8th graders, participate in this study. The first class sample is learning with Differentiated Instruction approach and the second class with the conventional learning. Data obtained using research instruments consisting of pre-test and post-test. Based on the results of data processing, it was obtained: (a) the mean achievement of communication ability of the students of Differentiated Instruction class is 77.37 in the medium level and the student of conventional class (75.87) in the medium level too; (b) to improve students’ mathematical communication ability, Differentiated Instruction approach is better to use. From the data that has been obtained, the effect of Differentiated Instruction is to improve students’ mathematical communication ability.
Analysis of higher order thinking skills 8th grade students in math problem solving
Authors: Rohman F M A , Riyadi R , Indriati D
Published: March 2020

This study aims to describe the higher order thinking skills of 8th grade students in mathematics problem solving. The sample used was one class consisting of 29 students and the class was selected based on purposive random sampling. Data collected through tests and interview. Data analyzed by descriptive analysis. The students are given mathematics problem solving test which includes HOTS level of analyze, evaluate and create. The result in the analyze level as many as 86.2% of students be able to differentiating, 48.3% of students be able to organizing, and 48.3% of students be able to attributing. In the Evaluate level as many as 72.4% of students be able to checking and 68.9% of students be able to critiquing. In the Create level, as many as 37.9% of students be able to generating, 31% of students be able to planning and 27.6% of students be able to producing.
Effect of geometric parameters on the performance of motorcycle catalytic converters
Authors: Lapisa R , Halim A G , Sugiarto T , K Arwizet , Martias M , Maksum H , Krismadinata K , Ambiyar A
Published: March 2020

The critical environmental issues of the Indonesian automotive market growth are the increase in air pollution. Vehicle exhaust emission can cause significant problems for the human health and the environment. Therefore, vehicle emission control is indispensable to mitigate the environmental problem. One of the most widely used methods to reduce automotive emission is utilization of catalytic converter in exhaust system. In fact, the catalyst performance in the reduction of noxious gases depends on its material and geometric design. This study aims to evaluate the effect of geometric parameter on the performance of motorcycle catalytic converters. In this experimental study, the catalytic converter made of brass foil plate is mounted on motorcycle muffler. The effectiveness of three catalyst geometry models namely flat perforated plate, folded perforated plate and rolled brass sheet, will be evaluated in relation to the reduction of hydrocarbon (HC) and carbon monoxide (CO) content. HC and CO emission levels are measured by four gas analyzers. The results show that the geometric parameter has a significant effect on HC and CO’s composition in the exhaust gas. For idle speed test, the second geometry model of catalyst presents the best performance in reduction of Hydrocarbon and CO2 concentration.
Peculiarities of electron emission from high-density deep levels of nanodefects in oxygen-implanted silicon
Authors: Danilov D V , Vyvenko O F , Loshachenko A S , Sobolev N A
Published: March 2020

The peculiarities of electron emission from electronic states of nanodefects formed at the early stages of oxygen precipitation in oxygen-implanted silicon annealed at 700°C were investigated with a combination of capacitance and current transient spectroscopy of the space charge region (SCR) in semiconductors. It was established that the particular properties of acceptor-like states are due to their high density and their localization at the back side of the implanted region. A model is suggested that explains an apparent emission rate slowdown and the appearance of an unexpected sign of capacitance relaxation signal as a result of the non-monotonic shape of the potential of the Schottky-diode.
Analysis of the 7x7 to 5x5 superstructure transition by RHEED in the synthesis of Ge on Si (111) in an MBE installation
Authors: Dirko V V , Lozovoy K A , Kokhanenko A P , Kukenov O I
Published: March 2020

In this paper, we consider the 7×7 to 5×5 superstructure transition during the synthesis of Ge epitaxial layers on a Si (111) surface in its temperature range from 250 to 700 °C. This transition is investigated by reflection high-energy electron diffraction (RHEED). As a result, the dependences of the critical thickness of the 7×7 to 5×5 superstructure transition on the substrate temperature are obtained for the first time.
Influence of plasma on electrophysical properties of the GaP/n-Si isotype heterojunction grown by PE-ALD
Authors: Baranov A I , Uvarov A V , Kudryashov D A , Morozov I A , Gudovskikh A S
Published: March 2020

The work is devoted to studying the influence of an additional step of argon plasma treatment on the quality of the GaP/n-Si isotype heterojunction grown by plasma-enhanced atomic-layer deposition (PE-ALD). Deep-level transient spectroscopy measurements demonstrated that argon plasma leads to the formation of defects with a high concentration in silicon wafers, unlike the PE-ALD mode without a step of hydrogen or argon plasma treatment. In addition, GaP layers obtained by PE-ALD have defects with an activation energy of 0.40 eV and 0.62 eV for processes with and without argon plasma treatment, respectively.
2D electrons and 2D plasmons in AlGaN/GaN nanostructure under highly non-equilibrium conditions
Authors: Loginov L A , Shalygin V A , Moldavskaya M D , Vinnichenko M Ya , Firsov D A , Maremyanin K V , Sakharov A V , Zavarin E E , Arteev D S , Lundin W V , Kauppinen C , Suihkonen S
Published: March 2020

We report on studies of electrically excited non-equilibrium 2D electrons and 2D plasmons in an AlGaN/GaN nanostructure. Optical access to 2D plasmons is provided by means of a metal grating fabricated at the nanostructure surface, while the properties of 2D electrons are examined in the samples without metal grating. The paper focuses on the creation of highly non-equilibrium conditions when the effective temperature of 2D electrons is much higher than the crystal lattice temperature. Such conditions are realized by applying short electrical pulses with a low repetition frequency. A method has been developed for independently determining the temperature of hot electrons and the temperature of the crystal lattice under an applied electric field. It has been shown that under highly non-equilibrium conditions the spectral density of terahertz electroluminescence of 2D plasmons can significantly exceed that of 2D electrons at a certain frequency.
Modelling of dielectric properties of non-linear optic materials based on linear molecules
Authors: Bulatov V Yu , Smirnov M B , Sukhomlinov S V
Published: March 2020

Dependence of polarizability (LP) and hyperpolarizability (HP) of linear oligomers on the number of monomers in the chain is analyzed. A critical review of previous studies revealed two main issues. Firstly, the specific (per one chain unit) values of both LP and HP monotonously increase along with the chain length, and secondly, both dependencies approach the limit values in sufficiently long chains. A model describing such behavior is proposed. The model parameters are LP and HP of an isolated chain unit and a cross-term, which couples the dipole moments of neighboring units. These parameters have a clear physical meaning. It is shown that the theoretical predictions provided by the model agree well both with the results of accurate quantum-mechanical calculations and with experimental data.
Integrated food assurance system
Authors: Fajri M
Published: March 2020

A good food is a food which is good at quality, safe and halal. A system is needed to ensure that quality, the safety, and its halal labeled. In Indonesia, quality assurance system, safety assurance system, and halal assurance system have not been integrated into one system. A food assurance certification in the form of GMP certificate, HACCP certificate, and also Halal certificate is carried out individually by the authorized institution (certification body, LPPOM MUI and BPOM). An individual certification costs a separate fee. This insignificant cost is certainly burdensome for small and medium enterprises (SMEs) which have a limited fund. This will certainly hamper the development of Food SMEs to compete in national or international market. The aim of this study was to produce recommedation for an integrated food quality, safety and halal assurance system. The research method applied was review of the requirements contained in ISO 9001, ISO 22000 and HAS 23000. The quality assurance system refers to ISO 9001 and GMP, the safety assurance system refers to ISO 22000 and HACCP and the halal assurance system refers to HAS 23000. The integrated system is expected to reduce cost of food assurance certification, especially for Food SMEs.
Effect of Groove Setting for Additional Reinforcement on the Seismic Performance of Precast Shear Wall-slab Joint with No Outer Longitudinal Reinforcement
Authors: Wang Minling , Guo Haishan , Qian Hongliang , Wang Dongyan , Wang Huajie
Published: March 2020

The superimposed slab with no outer longitudinal reinforcement at the bottom is a new slab for the assembled shear wall structure, which has a simple detailing and is easier to be transported. To improve the joint performance, the additional reinforcements were often used, but the effect of groove setting at the position of contact between the precast slab and casting slab has not been known clearly. A cyclic loading test was designed and conducted to investigate the influence of groove setting to seismic performance of precast shear wall-slab joint with no outer longitudinal reinforcement. The hysteretic curves and key indexes for the seismic performance of these joints were gained. Also, the influence rule of groove setting to the seismic performance of the joint was studied, and the result showed that groove setting could improve the seismic performance of the joint effectively.
Experimental Study on CFRP Strengthening Hollow Wooden Column and Strengthening Effect
Authors: Chen Qiang , Chen Chaoyun , Yu Fang , Shen Bo , Tan Cong
Published: March 2020

Historically, timber, as a main construction material has been applied in the field of construction, timber structure is building in the middle part of a very large proportion, but the wood will happen after a long time after the use of decayed, cracking, crispy and other diseases, result in loss of structure strength and buckling problems of influence continue to use, has quite a number of ancient architecture of China is a wooden structure, at the same time many wooden structure has important historical significance and research value, at the same time, for building a timber of strengthening the study of the problems of the less, to solve the problem of building a timber reinforcement, In this paper, a model is proposed to improve the bearing capacity of the damaged wooden columns by reinforcing them with carbon fiber sheets to limit the lateral displacement. In the test, three pillars with basically the same materials, structural dimensions and processing methods were used to repair and reinforce the damaged logs, and the bearing capacity of the hollow columns under axial compression was tested. The experimental results show that the bearing capacity of the building columns strengthened by CFRP is significantly increased: the average ultimate bearing capacity is 1003.33kn, the lateral displacement is reduced to a certain extent, and brittle failure occurs, which proves that the research results provide a certain practical and theoretical reference for the field of building column reinforcement.
Comparative Analysis of the Structure and Construction of the Central-Column Drum Tower and the “Hui” Type Drum Tower of Dong Nationality in the Southeast of Guizhou Province
Authors: Pu Shuang , Fan Langbo , Liang Bo , Huang Chuanteng
Published: March 2020

Dong is a minority in China. The drum tower is the representative architecture of Dong culture and also is the traditional cultural symbol of the region of Southeast of Guizhou Province. This paper mainly compares the structure and construction features of the central-column drum tower and the “Hui” type drum tower, taking the Shudong drum tower in Liping County and the Zengchong drum tower in Congjiang County as examples. Both of the drum towers are in the Southeast of Guizhou Province. By analyzing the drum tower classification, planar form, column layout, structural components and construction technique, the differences between the two types of drum towers in the structure and construction were compared. This article could contribute to understand the drum tower in a clearer and more intuitive way.
Parametric static analysis of a new type of fabricated plate grillard thin shell roof structure
Authors: Liu Kai , Wu Xuewen , Zhao Xueying , Hong Cheng , Yi Shuai
Published: March 2020

The new fabricated slab ribbed shell roof structure is a new structure based on a large-span steel-concrete composite thin shell roof. An assembly unit composed of a thin-walled steel ribbed plate, a base plate, and concrete provided with bolt holes, and a plate-grid thin shell roof structure formed by the assembling and connecting assembly units. Considering the influence of the structure’s rise span ratio, five groups of rise span ratios were used for finite element analysis and compared with single-layer cylindrical reticulated shells. The analysis shows that the mean value of the ultimate load of the new prefabricated panel latticed thin shell roof structure is increased by 5.3% on average compared with the single-layer cylindrical reticulated shell structure. When the rise span ratio is 1/5, the structure has the largest stiffness and the smallest deformation; when the rise span ratio exceeds 1/5, the growth trend in the ultimate load that the structure can withstand will become smoother, and the average maximum displacement will decrease by 4.3% compared with the single-layer cylindrical reticulated shell, which shows that the grid lattice structure has better stiffness.
Parameter Analysis for Seismic Performance of Prestressed Fabricated Frame Joint Based on Opensees
Authors: Wang Chenchen , Xu Hongjun , Zhang Jingdong
Published: March 2020

Aiming at the characteristics of prestressed fabricated frame joints, proposes a finite element modelling method based on OpenSees. Then, verify the correctness of the finite element model combining experiment of prestressed fabricated frame structure. it shows that the proposed joint finite element model can predict the seismic performance of the structure accurately. Detailed parameter analysis is performed to study the general law of seismic performance evolution of joint from five aspects, namely, prestressed tendon area, energy-dissipating tendon area, concrete strength, axial compression ratio, and tensile control stress. Analysis results show that prestressed tendon area, axial compression ratio and tensile control stress should be constrained to some extent, otherwise the performance of joint would deteriorate.
Experimental Study on Seismic Behavior of K-type Eccentrically Braced Steel Frame with Semi-rigid Joints
Authors: Shi Qiang , Su Jin , Wang Xinwu , Shilin Yan
Published: March 2020

In order to study how different connection types and floor height affect the seismic behavior of eccentrically braced steel frame, there has been processing 4 pseudo-static tests for eccentrically-braced steel frame, including two one-layer specimen and two three-layer specimen. The seismic behavior of the specimen has been analyzed according to hysteresis curve, carrying capacity, stiffness degeneration, ductility, and energy dissipation ability etc. The experiments’ results show that the connection types have greater impact on seismic behavior, adopting specimen destruction model of high-strength bolts connection as beam segment end-plate weld or web fracture. The rest of components do not appear significant yielding deformation and crack, which caters for post-earthquake restoration and replacement of energy dissipation beam segment. The carrying capacity of high-strength bolts connection specimen is slightly lower than welded connection specimen, but the ductility of the former is far beyond the welded specimen. Because of the slippage between components, hysteresis curves of bolts-connected eccentric braced steel frame structure appear to have pinned phenomenon with various degrees.
Reliability Analysis and Safety Improvement Measures Research of Transmission Line Tower-Line Structure under Ice-Wind Conditions
Authors: Shi Tianru , Hu Danhui , Zhou Xueming , Zhang Yaodong , Feng Zhiqiang
Published: March 2020

The tower-line structure system of transmission line is a whole composed of tower structure, insulator, fittings and grounding wire and other components or subsystems. Its reliable operation is of great significance to the safe and stable operation of power system. In this paper, the reliability analysis method of transmission line tower-line structure system under the combination of ice and wind is modeled. Firstly, the reliability index of pole-tower structure, insulator, fittings and grounding wire is calculated by checking point method of first-order second-moment method. Then, the reliability calculation method of series structure system is used to calculate pole-tower structure, insulator, fittings and grounding wire. Finally, taking a straight tower and tension tower as examples, the system reliability indices of pole-tower structure, insulator, fittings and ground wire under ice-wind combination are calculated and analyzed, which can provide reference and guidance for disaster prevention of transmission lines.
Monitoring Construction Progress Based on 4D BIM Technology
Authors: Chen Jingjing , Wu Juan , Qu Yan
Published: March 2020

With the development of building information model (BIM), the new theory and technology of project management are developing continuously. The purpose of this project is to combine BIM and 4D technology on the basis of existing construction management theory and intelligent construction concept, and effectively solve the “information island” phenomenon in the construction process. Realize the optimization of construction progress and real-time perception and control of actual construction progress. Using database theory to study the innovation of this technology will enrich the theory and method of project process management and promote the research and application of new information technology in construction industry. Using new methods to improve the level of project management is conducive to improving the construction efficiency of the project.
A Comparison of the Mechanical Vibration Evaluation Standards of Steam Turbine Generator Foundation
Authors: Zhang Qian , Chen Jie , Lu Zhicheng
Published: March 2020

In the paper, the basic design standards (GB50040-96 and ISO10816-2) of various mainstream steam turbine generators at home and abroad were reviewed and their similarities and differences were analyzed in detail. Moreover, the paper also provides the vibration test data on the disturbing points of the foundation and corresponding bearing bracket of three typical 600MW turbine generator units during normal operation so as to search for the relationship between vibration of bearing brackets and vibration of the foundation. The safety coefficient of the chosen foundations using GB50040-96 and ISO10816-2 were also given to compare the severity of each standard. It is hoped to provide designers with accurate grasp of various standards.
An Improved Model on Pipe Soil Vertical Interaction
Authors: Li Kai , Qian Jing , Lei Chengbin
Published: March 2020

The existing three typical models on pipe soil vertical interaction mainly consist of RQ model, AB model and ABY model. Without exception, each model comprises four fundamental phases of pipe soil interaction: no contact, initial penetration, uplift and re-penetration. Both RQ model and AB model can describe the above four phases, however, they give no idea of the cyclic weakening effect on soil mass. For ABY model, it can reflect the soil mass weakening changes and the pipeline slotting process, yet it may greatly underestimate the soil mass strength and then overestimate the buried depth of pipelines. This thesis proposes an improved model on pipe soil interaction. It adopts a more rational method to consider the weakening effect of soil strength. Furthermore, this model can take the pipeline slotting effect into account. Therefore, it is an optimized model to reflect the dynamic buried-depth change in the process of interaction between pipeline and soil mass.
Research status of distinct element method particle flow analysis method and its application in deep sea core drilling
Authors: Ren Yugang , Yu Kaiben , Zheng Sen , Yang Lei , Qi Haibin , Zhang Jianhua , Liu Yanjun
Published: March 2020

Discrete element particle flow method (DEM) is a numerical simulation method aimed at the discontinuity, non-uniformity and non-linear mechanical properties of rock mass. It analyzes the damage and fracture mechanism of materials and structures from the perspective of micromechanics. It has been widely applied in different disciplines and engineering fields. This paper firstly introduces the basic principle of discrete element particle method and its calculation theory, the second review conducted extensive research, the method of this paper expounds in detail the progress at home and abroad, and analyses the application in the field of rock drilling medium, the final mechanical properties of the deep core drilling analysis apply to imagine thinking and research.
Numerical Simulation Study on Fully-Mechanized Top Coal Caving in Extra-Thick Coal Seam
Authors: Lei Wu-lin , Li Xingliang , Chen Yanfeng , Duan Weihua , Chen Jianhua
Published: March 2020

Three working face of a mine 250203, 250205, 250206 as the research object, the establishment of a geomechanical model according to the actual situation of the project. FLAC3D using numerical simulation method to analyze section coal pillar width in 20 m, 10 m, when 0 m, Face sequential mining process key strata caving stride, the instability from the pillar damage induced rock burst dangerous. The results showed that: (1) the reasonable width of coal pillars can effectively reduce the occurrence of rock burst; (2) a composite key layer of destruction and instability is the main mine rock burst occurred.
Prediction of V
s30 in Datong Basin and Amplification Effect of Site Ground Motion Based on Typical Geological Characteristics Analysis
Authors: Zhang Longfei
Published: March 2020

Shear wave velocity of soil layer is an important dynamic parameter, which is of great significance for site classification, determination of ground motion parameters and prediction of ground motion. Based on the analysis of shear wave velocity data of 1429 geological boreholes in Datong Basin, this paper studies the relationship between V
S and geological characteristics such as soil type, geological unit type, SPT blow number and compactness degree. Based on the correlation analysis of shear wave velocity ratio of soil, soil compactness coefficient and thickness of Quaternary upper overburden, this paper presents a soil V
S30 prediction model. The goodness of fit R
2 > 0.90 and the prediction accuracy is very high under the overall sample condition. Based on the abundant strong earthquake records and drilling information of KiK-net and K-net networks in Japan, V
S30 and site period T
S are selected as the two quantitative indexes of the amplification effect of site ground motion. The correlation between V
S30 and PGA amplification coefficient and site period T
S is established. The distribution characteristics of PGA amplification coefficient and site period T
S based on V
S30 distribution are given. The results show that the maximum values of PGA amplification coefficient and TS distribution characteristics of site period are consistent with the geological location of the earthquake swarm with M6.1 in 1989 in Datong Basin. It shows that the characteristics of the site ground motion effect estimated by V
S30 can indicate the occurrence of earthquakes. The occurrence of earthquakes is affected by active faults and local conditions of the site at the same time, which fully proves the feasibility of this research method and the accuracy of the research results. The shear wave velocity ratio and the soil compactness coefficient are proposed for the first time, and they are applied to the prediction of V
S30 with the thickness of the upper overburden of the quaternary system. This paper provides a good research idea for V
S30 prediction of non-shear wave velocity test site, study of amplification effect of site ground motion, study and judgment of earthquake location. The research results can provide important technical support for urban earthquake prevention and mitigation planning, large earthquake scenario construction, earthquake risk analysis, earthquake damage prediction and regional earthquake safety evaluation in Taiyuan Basin.
A New Method of Modeling Shield Tunnel in Mixed Strata Based on FISH Language
Authors: Qiu Yuefeng , Chen Jian , Yi Shun
Published: March 2020

In order to solve the problem specific to modeling shield tunnel in mixed strata with FLAC3D, a new method based on FISH language is proposed. By means of the new proposed method, the shield tunnel as well as the stratum inside and outside the tunnel are precisely modeled in FLAC3D. Compared with the traditional way, the new method in the paper is both convenient and accurate. Then the new method is proved to be reasonable through the numerical result of an instance. Consequently, the new method in the paper can be applied to further numerical analysis in FLAC3D.
Discussion on the Review and Outlook of Microbial Geotechnical Mineralization Technology
Authors: Lang Chaopeng , Li Mingdong , Dai Renhui , Pan Yaosen
Published: March 2020

Microbially Induced Calcite Precipitation (MICP) has grown up to be a hot topic in geotechnical engineering. MICP is a technology that controls and utilizes microbial reactions to produce calcium carbonate cement. It can be used to solve problems in geotechnical engineering, such as improving rock and soil strength, reducing permeability, treating the polluted soil. Microbial mineralization involves a series of biochemical reactions, and the curing process is of particular importance. Therefore, the curing effect of MICP is restricted and impacted by many factors. Built on the factors of microbial mineralized calcium carbonate reaction and microbial mineralization, the principles of urea hydrolysis, denitrification and sulfur reduction were summarized. The effects of air conditions, environmental factors, fiber addition amount, soil water content, and treatment solution concentration on microbial mineralization technology were analyzed. The conclusion is as follows: in the aerated state, the calcium carbonate content is the highest; the low urease concentration, the natural climatic temperature (the best in summer), the pH value between 7-9 produces the most calcium carbonate and the compressive strength is the largest; When soil fiber content is 3%-5%, MICP technology works best; the low concentration treatment liquid is more suitable for the MICP technology; the microbial mineralization technology is suitable for the sand, but it can also produce good effects for other complex soil.
Research on Fatigue Bending Stiffness Degradation of Prestressed Concrete Beams Considering Size Effect
Authors: Zhou Hongyu , Zhou Yun , Liu Yanan , Ma Quanzhou
Published: March 2020

Based on the fatigue damage development law and damage model of concrete, considering the crack propagation of ordinary steel bars and prestressed reinforcement under fatigue load, the residual useful section area of reinforcement was used to reflect the fatigue damage of steel bars. Further, we considered the correction coefficient of the size effect of concrete and steel bars and derived the formula for calculating the section stiffness of prestressed concrete beams of different sizes after fatigue damage. A multi-stage variable amplitude fatigue load test was carried out on prestressed concrete beams. The test results were analyzed, and the accuracy of the equation was verified based on experimental data. The results show that the stiffness degradation of prestressed concrete beams and the development of concrete damage under the multi-stage variable amplitude fatigue loading test have similar laws. According to the theoretical derivation formula, the deviation between the calculated results and the experimental results is small, which has reference value for the study of the fatigue bending stiffness degradation of prestressed beams considering the effect of size effect.
Experimental Investigation on the Behaviour of Non-reinforced Ultra-High Performance Concrete Slabs
Authors: Zheng Hui , Zhou Dongdong , Liao Zhenhao
Published: March 2020

Ultra-high-performance concrete (UHPC) is expected to provide solutions for the development of lightweight, high-strength, and rapid construction of concrete bridges due to its excellent material properties. In order to study the influence of steel fiber on the bending performance of non-reinforced UHPC (NR-UHPC) slabs, the bending failure test of 8 NR-UHPC slabs was completed with the steel fiber content as a parameter, and the failure mode, load-deflection, crack widths and load-strain curves of the test slabs were analyzed. The test results show that the destruction process of the NR-UHPC slabs can be divided into three stages: elastic stage, cracking stage and failure stage. The load-deflection curve and load-strain curve of the specimen with steel fiber content of 0.5%-1% change linearly during the elastic phase. In the elastic phase, the load-deflection curve and the load-strain curve of the test piece with a steel fiber content of 2%-3% were not smooth after the linearity begins; the strain of the UHPC slab was almost the same within 0-10 kN. However, as the load increased, the larger the amount of steel fiber was, the smaller the strain was, that is, the UHPC slab had good crack resistance. According to the regression analysis of test results at home and abroad, recommended design formulas for the bending bearing capacity of NR-UHPC slab were put forward, which tally well with the test results.
Numerical Analysis of Bolt Support at Roadway Intersection in Yanghui Mine, Vietnam
Authors: Li Pengfei , Cao Chen , Van Cong Tran
Published: March 2020

The stress of surrounding rock at roadway intersection is complex. U-shaped steel support has been used at the roadway intersection of Yanghui Mine in Vietnam, but there are many problems, such as blocked ventilation and limited passing capacity. In this paper, FLAC3D numerical simulation software is used to simulate the support effect of U-shaped steel and bolt based on the field data of Yanghui Mine. The deformation of roof, floor and two sides are compared. The results show that the bolt support can be applied to the intersection of roadways in the mine to improve the support of the mine.
Experimental Research on the Deformation and Failure Characteristics of Coarse-Grained Soil Slopes in Seasonal Frozen Region along Sichuan-Tibet Railway
Authors: Zhao Mengyi , Xie Qiang , Ren Xinhong , Zhu Lei , Chen Pengfei
Published: March 2020

The field investigation of the seasonal coarse grained frozen soil slopes along the eastern section of the proposed Sichuan-Tibet railway shows that the deformation and failure of the slopes are widespread. In order to explore the deformation characteristics and failure mechanisms of the slopes in this area and provide a basis for the design and protection of the slopes along Sichuan-Tibet railway, laboratory model tests on the seasonal coarse grained frozen soil slopes under snowfall conditions were conducted. The results show that, the deformation and failure of the seasonal coarse grained frozen soil slope are caused by the repeated alternation of the failure of the surface soil structure caused by frost heave and the surface soil saturation caused by snow thaw infiltration, and the reduction of the shear strength of the surface soil under repeated freezing and thawing conditions. The deformation and failure of the seasonal coarse grained frozen soil slopes along the eastern section of the Sichuan-Tibet railway are mainly characterized by creep-flowed, topsoil slip and slippage on slope surface. The emphasis of slope protection in this area are slope thermal insulation and waterproof.
A Study on the Friction Dynamic Response of Asphalt Pavement Considering the Unevenness
Authors: Zhang Endong
Published: March 2020

In order to quantitatively analyse the influence of pavement unevenness on the stress of asphalt pavement, a tire-road coupling model with stable rolling was established. Sinusoidal wave is used to describe the pavement unevenness, and based on the established tire-road coupling model, different conditions of axle load and base elastic modulus are used to analyse the influence of unevenness on the dynamic response of asphalt pavement. The results show that the influence of unevenness on vertical stress of asphalt pavement increases with the increase of axial load. As the elastic modulus of base increases, the vertical stress of asphalt layer will decrease, while the vertical stress of base layer increases. But the influence of unevenness on dynamic response of asphalt pavement cannot be eliminated. Therefore, the unevenness should be taken into account in the simulation of real road surface.
Research on On-Site Monitoring and Measurement Technology of Tunnel
Authors: Li Chongxue , Wang Mingfei , Gao Xuekai , Yang Bin
Published: March 2020

The frequent occurrence of tunnel safety accidents threatens the safety of people’s lives and property, and the research on the on-site monitoring and measurement technology of tunnels is very necessary. Practical applications of tunnel on-site monitoring and measurement technology include electronic total station and micro-deformation monitoring radar. Among them, radar interferometry technology is used for deformation monitoring in on-site monitoring and measurement, such as vault settlement. The built millimeter wave radar deformation measuring instrument can complete the vault settlement monitoring of the tunnel on-site monitoring. During the tunnel construction period, it is necessary to make a selection according to the specific engineering objectives, adopt appropriate observation and test methods, obtain new deformation displacement information, and analyze and predict the deformation of the construction.
A Model Calculation of the Air Flow Regimes and Thermal Patterns in a Subway Station Using STESS Software: The Case of Iran
Authors: Zhi Yansheng
Published: March 2020

This study examines the impact of mode of ventilation and equipment operation on air flow regimes and thermal patterns of subway stations and channels to provide actionable guidance for selecting design tactics that are based on the normal and accident conditions. A case analysis and STESS software were conducted utilizing a station without platform edge doors and the two lines channel with slopes up to 50‰ to access the impact of ventilation and equipment operation on occupant exposure. As such, the results of the case in Iran analysis emphasized the application of STESS software is suitable for simulating the ventilation tactics and improving the air flow regimes and thermal patterns of the stations and channels in normal and accident conditions.
The Design and Study on Long-Span Road-Rail Cable-Stayed Bridge
Authors: Zhang Xianqing , Guo Shulun , Lei Junqing
Published: March 2020

The main content of this paper is to study the Steel Road-Rail Cable-stayed Bridge with a main span of 1200m. The finite element model is established by large-scale analysis software to calculate the response of the structure under load. Based on the calculation results, the rationality of long-span cable-stayed bridge are preliminarily researched in this paper.
Study on Ground Motion Intensity Measures for Seismic Response Evaluation of Circular Tunnel
Authors: Zhang Chengming , Zhong Zilan , Zhao Mi
Published: March 2020

Ground motion intensity measure (IM) is a key link between the seismic hazard analysis and structural seismic response analysis, which play an important role in the performance-based earthquake engineering framework. In order to find suitable IM for seismic response evaluation of circular tunnel, nonlinear dynamic time-history analyses are conducted on a two-dimensional finite element model of tunnel-surrounding rock interaction in this study. The near field ground motions without velocity pulse and far field ground motions as recommended by FEMA-P695 are used as the input ground motions for the numerical model. Besides, the overall lining damage indices in compression and in tension are used as engineering damage measures (DMs) to estimate the lining damage state. The applicability of 20 existing ground motion IMs commonly used in engineering practice are investigated in this study. Statistically regression analysis is carried out for results obtained from nonlinear time-history analyses. Based on the criteria of efficiency and sufficiency, Arias intensity is identified as the optimal IM for seismic response prediction of circular tunnel structure.