bluuebunny/crossref_metadata_2025 huggingface dataset:
Cyclist test on particleboards and utilization of their liquid disposal for fertilizer
Authors: Nuryawan A , Siringo-Ringo F J , Nasution T I , Banurea R , Hartini K S , Elfiati D
Published: April 2021

Cyclist test on particleboards (PBs) bonded urea-formaldehyde (UF) resin was intended to be carried out in order to predict their degradation thus recycling of these products was possible. In this contribution, PBs bonded by five types of UF resins namely 0.95; 1.05; 1.15; 2.00; and commercial were examined using cyclist test. The test consists of cycles of five treatment steps, i.e., measurement of initial thickness dimension, immersion in water at ambient temperature for 24 h, measurement of swelling thickness dimension, drying in convection oven at (103 + 2)°C for 24 h, and measurement of oven-dry thickness dimension. This cycle was applied until the specimens were not possible to be measured their thickness because of broken-down of the PBs. Further, water disposal in this experiment, then was utilized as fertilizer to Swietenia mahagoni seedlings. Observation on growth parameters (stem height and diameter) and biomass parameters (dry weight of top and root) of the seedlings were conducted for 12 weeks after planted. Result of this study showed PBs bonded by low mole of UF resins (0.95; 1.05 and 1.15) have had faster degradation compare to those of 2.00 and commercial one. Both growth and biomass parameters of the seedlings increased but statistically not different among the samples. These findings suggested that PBs bonded UF resins can be recycled using water-soaking process and the liquid disposal of this activity can be utilized as fertilizer.
Application of Trichoderma sp. to leaf litter decomposition (Rhizophora mucronata) on various salinity levels in Belawan
Authors: Yunasfi  , Aulia S P , Hartini K S
Published: April 2021

Mangroves can be defined as forest vegetation that grows between tidal lines or is affected by tides. Trichoderma sp. is one type of fungus that is found in almost all types of soil and in various habitats which is one type of fungus that can be used as biological agents controlling soil pathogens. The purpose of this research is to know the acceleration of the decomposition rate of R. mucronata leaf litter by Trichoderma sp. at various levels of salinity in Belawan and test the carbohydrate and protein content. The research was conducted in December 2019-March 2020. The technique of placing the sample in a litter bag is placed at 3 points of the observation station based on differences in salinity. Decomposition rate values obtained were 10.20 at station I, 8.50 at station II and 7.05 at station III from the initial weight of observation on the days-15 to the observation period on the 90 day. The highest carbohydrate content was at Station I on the days-60 which was 13% and the lowest carbohydrate yield on the station III on the days-15 was 2.42%. The highest percentage of protein is 9.7% on the days-15 at station III and the lowest percentage of protein is 4.83% on the days-15 at station I.
Spatial distribution characteristics of human-elephant conflict (HEC) in Besitang
Authors: Sulistiyono N , Maulana M I , Patana P , Purwoko A
Published: April 2021

The conflict between humans and wildlife tends to increase lately, especially the human-elephant conflict (HEC). The high level of human activity around the forest causes an increase in the rate of forest destruction. The opening of agricultural land in and around the forest, causing the elephant habitat to become narrow so that the elephant looks for new space to move to community land. HEC occurs when elephants and humans fight over the same resource. The purpose of this study is to obtain information on the characteristics of the spatial distribution of human-elephant conflict in Besitang. The method used in this study is the analysis of HEC points overlay with several biophysical variables using GIS. The results of this study show that the distribution of HEC occurs mostly in sloping areas with low topography and areas relatively close to forests, plantations / agricultural communities, settlements, and rivers.
Endoparasites of cattle raised under intensive and semi-intensive system at Klumpang Kebon Village, North Sumatra
Authors: Tanjung M , Thahira D
Published: April 2021

Endoparasitic infestations tend to occur in all cattle breeding systems with different level of infection at spatial scale. This study aimed to distinguish the prevalence of endoparasites of cattle raised under intensive and semi-intensive systems at Klumpang Kebon Village, Hamparan Perak District, North Sumatra, Indonesia. Fresh dung samples were collected from 40 cattle and pre-treated with glass beads sedimentation method to obtain the endoparasite suspensions. The results showed that majority of cattle (35 out of 40) were infected by four endoparasitic species identified from the dung samples, namely Buxtonella in the class of Ciliata, Dicrocoelium, Fasciola, and Paramphistomum in the class of Trematoda with the absence of Fasciola in the semi-intensive breeding system. The percentage of infected cattle was higher in semi-intensive farm (100%. 20/20) than in intensive farm (75%. 15/20) in which the highest infestation of endoparasites were recorded from Paramphistomum (88.6%), followed by Buxtonella (65.7%), Fasciola (37.1%), and Dicrocoelium (2.8%). Most cattle were mostly found with two co-infecting endoparasites and higher percentage was recorded in semi-intensive breeding system. Based on the highest endoparasites prevalence there is a need to apply a parasitic control program to both breeding systems to prevent further infections.
Effect of duration of illness and lipid profile of type 2 Diabetes Mellitus patients on diabetic retinopathy
Authors: Amelia R , Sari M D , Virgayanti V , Ariga R A , Harahap M S
Published: April 2021

Diabetic retinopathy (DR) is one of complication chronic of Diabetes Mellitus (DM). The purpose of this study is to analyze the impact of duration and lipid profile (dyslipidemia) on the prevalence of DR complications in patients with type 2 DM in Medan. This research is a cross-sectional study. The population was typed 2 DM patients at primary care in Medan with sample of 89 patients. The research data are primary, assessment of lipid profile by taken venous blood and examination by the Enzymatic Colorimetric method, while the determination of DR complications using indirect fundoscopy. Data were processed with SPSS with Independent T-test analysis. The results showed the duration of illness and triglyceride levels had a strong relationship with DR in type 2 DM patients (p <0.05), while total cholesterol, HDL-C, LDL-C levels had a weak relationship (p> 0.05).
Analysis of water quality and nutrient content in the Belawan River
Authors: Yeanny M S , Barus T A , Mawengkang H , Mulya M B
Published: April 2021

The goal of this research was to analyze the water quality and nutrient content in the Belawan River. Activities done by the community such as industries, PLTU, PDAM and aquaculture are found in Belawan River area. This action produce waste straightly discharged into river water, emerging several bad effect on water quality and nutrient content. Retrieval of data with Purposive Random Sampling with five analyses the location. Analysis in the form of measurements of water quality that are temperature, pH, depth, light intensity, light penetration, flow speed, dissolved oxygen (DO), BOD5 and the measurement of nutrient content, which are nitrate, phosphate and nitrogen. The results of water quality measurements indicated that temperature, light penetration, light intensity, flow speed, and depth are still within the water quality standard while pH and BOD5 have passed the water quality standard. Based on nitrate concentration, it is included as eutrophic and mesotrophic waters (1.18 - 7.57 mg/L). Based on phosphate concentrations, it is included as hypertrophic (0.14 - 0.18 mg/L,). Based on nitrogen concentration, it is included as eutrophic and mesotrophic waters (1.54 - 10 mg/L).
The utilization of mushroom growing media waste as raw material for biogas production: energy productivity ratio (EPR) study
Authors: Irvan  , Trisakti B , Nabilah Y
Published: April 2021

Indonesia is one of the countries with the largest crude palm oil (CPO) production. Besides CPO production the mills also produce various type of wastes in large quantity. Oil palm empty fruit bunches (OPEFB) are the largest solid waste produced during the process. One of the OPEFB utilizations that has been done by the community around the mills area is to make mushroom as growing media. However, the rest OPEFB from mushroom media which cannot be degraded becomes a new problem for the community. The technology that can be used to overcome this waste is the anaerobic composting process. This paper describes the utilizing OPEFB waste from the rest of the mushroom growth media into energy through the anaerobic composting process. The energy productivity ratio (EPR) was also calculated and reviewed during the process and utilizing by products in the output. The result revealed that the design of OPEFB waste treatment into biogas and its purification are expected to be applied to the concept of clean production (zero waste) and the productivity ratio of energy values obtained from calculations was > 1. This shows that the needs of energy output in the pilot plant are greater than the input.
Antioxidant activity of liverworts Marchantia paleacea Bertol. from North Sumatra Indonesia
Authors: Siregar E S , Pasaribu N , Sofyan M Z
Published: April 2021

Research on antioxidant activity of Marchantia in Indonesia is still limited. The objective of the study is to investigate the antioxidant activity of Marchantia paleacea from North Sumatera, Indonesia. The method of extraction in this study using maceration with methanol. The antioxidant activity of extracts were evaluated by 1,1diphenyl-2-picrylhydrazyl (DPPH). Vitamin C was used as positive control. The results showed that the extract of M. paleacea has antioxidant content with LC50 value of 25.25 μg/mL. The antioxidant activity of M. paleacea is classified as a strong category. The results obtained in the recent study indicate that M. paleacea is a potential source of natural antioxidant.
Damage Identification of Semi-Rigid Connection in Structures Based on Nonlinear Vibration Characteristics
Authors: Zhuo Debing , Cao Hui , Zhang Xiaobing
Published: April 2021

A damage-detection methodology based on nonlinear vibration characteristics was presented in this paper to identify damage of semi-rigid connections due to looseness of high strength bolts. In various damage cases caused by different loose severity of bolts in different positions, a specimen with semi-rigid connections was test and acceleration signals of free vibration were recorded by sensors placed at its both ends. The recorded signals were then dealt with by wavelet de-noising and blind source separation to get the first vibrational components. By Hilbert transform of these components, the amplitude-frequency curve of each case was obtained. The results showed that vibration of the specimen with semi-rigid connections presented typical nonlinear characteristics. With the increase of connection damage, the nonlinear degree increased accordingly. When one end had larger connection damage than the other one, it exhibited greater nonlinear extent. The results prove that it is valuable to apply the suggested nonlinear vibration characteristics based procedure to identification of semi-rigid connection damage.
Attenuation Zones of Combined Periodic Foundations with Different Combination Patterns
Authors: Liu Xinnan , Ren Yiqiang , Song Xiaoruan , Ji Yingbo
Published: April 2021

One-dimensional periodic foundations with single-size unit cells are difficult to possess attenuation zones with both low frequencies and wide bandwidths. Combined one-dimensional periodic foundations are proposed by combing unit cells with different sizes in tandem in this paper. Attenuation zones of combined one-dimensional periodic foundations with different combination patterns are compared. The present study is useful for the design of one-dimensional periodic foundations to isolate low frequency seismic waves.
Research on Contact Explosion Response of Reinforced Concrete Slab
Authors: Wei Demin , Hu Chenxi
Published: April 2021

In order to compare the contact explosion response of reinforced concrete in the air to that under the water, a FEM model based on multi-material fluid-structure coupling method is constructed to simulate the responses and failure process of two-way reinforced concrete slabs under contact explosion. The model is verified by fellow tests, then used to calculate dynamic responses and damage conditions of two-way reinforced concrete slabs subjected to underwater contact explosion and air contact explosion. It is found that the local destruction area of the slab subjected to underwater contact explosion roughly turned into a circle, while it turned into a rhombus for air contact explosion. Nonetheless, the damage of the reinforced concrete slab subjected to underwater explosion is more serious.
Analysis of Economic Thickness and the Suitable Insulation Thickness of External Wall Insulation Layer
Authors: Shen Tianqing , Shen Xingwei
Published: April 2021

From the view of appropriate technology, this paper compares and analyzes the calculated thickness, feasible thickness, economic thickness, and appropriate thickness of the external wall insulation material with the highest contribution rate from the economic point of view, and obtains the relationship, curve, and model between the economic thickness and the appropriate thickness of the thermal insulation material. The purpose is to provide a reference basis and model for the optimal design of building energy-saving external walls. It inspires the architectural designers to consider the energy conservation of buildings from the economy’s perspectives and environment to get the optimal and environment-friendly energy-saving design method. The purpose is to provide a robust theoretical basis for guiding energy-saving housing investment and reducing the blindness of investment.
Simulation Study on the Influence of Indoor and Outdoor Ventilation on Thermal Comfort in Zero Energy Buildings
Authors: Gao Chunxue , Xiang Jintong , Wu Songlin , Liu Qiuxin
Published: April 2021

Based on the rational utilization of natural wind, it is particularly critical to study the role of natural ventilation convection in zero energy buildings, so as to reduce building energy consumption and lay a good foundation for realizing the goal of zero energy consumption in buildings. The commercial software PHOENICS is used to numerically simulate the outdoor wind environment of the building complex layout and the indoor ventilation of the building itself. After a comparison analysis of simulation models, this paper first points out the main factors that affect the wind environment and indoor natural ventilation of the building complex. Reasonable suggestions were given to the architectural planning and design as well as the living habits of the residents which can save energy to the greatest extent. With these suggestions, the unnecessary energy consumption of air conditioning can be reduced on the premise of ensuring the indoor temperature and humidity environment which is very beneficial to the realization of zero energy consumption of buildings.
Research on BIM Reconstruction Method Using Semantic Segmentation Point Cloud Data Based on PointNet
Authors: Xiong Zhaoyang , Wang Ting
Published: April 2021

As the construction industry is shifting from the construction of new buildings to the maintenance and use of existing buildings in recent years, the demand for automated building information models (BIM) creation is increasing. This paper uses the deep learning network PointNet to perform semantic segmentation on the public S3DIS point cloud data set, which means to assign the same type of point cloud building components in the data set to the same label, and the bounding box algorithm is been used to obtain the outer contour parameters of the segmented point cloud building components. Finally, the Dynamo, which is one of the Revit plug-in, is used to perform parametric modeling according to the obtained parameters, and generates the BIM corresponding to the point cloud data set. The experimental results show that the method proposed in this paper can complete the parametric creation of BIM with high completeness based on the efficient segmentation of point clouds.
Research on the Durability of Composite Pile Made of Ultra-High-Performance and Common Concrete: Finite Element Analysis
Authors: Li Wei , Li Yiping , Shang Jianguo , Chen Yuhong , Zu Jinlong
Published: April 2021

The paper is to study the durability of transmission tower foundation using a combination of ultra-high performance concrete (UHPC) and common concrete (NC) in salinealkali region. The composite pile is made of outer UHPC sleeve and core ordinary concrete. Due to the excellent durability of UHPC, the outer UHPC sleeve can prevent chloride ion and sulfate ion corrosion as well as save cost. Computer research technology was used to construct a corresponding natural environment for artificial simulation, hence accelerate the experimental test of the natural environment. It can more directly and effectively reflect the durability problems of the actual projects. This paper follows the application of classical similarity theorem of UHPC-NC foundation under saline-alkali erosive environment in Gansu, concrete test beams with the same material composition and structural characteristics were poured, an accelerated artificial simulation was designed. Results on the finite element simulation revealed that the outer wrapped ring of UHPC can effectively block the transmission of chloride ions from the external environment to the center of the cross-section. Under the same environment and operation time, the penetration depth of chloride ion in UHPC-NC combined cross-section is much smaller than that in pure normal concrete cross-sections. Therefore, it can be seen that the UHPC-NC combined cross-section can prevent the penetration of chloride ions in a saline-alkali environment, thereby effectively improving the durability of the transmission structure foundation, and hence ensuring the safety and applicability of electricity transmission structure during operation phase.
Experimental Study on the Influence of Vibration Mixing Technology on Engineering Characteristics of Steel Fiber Reinforced Concrete
Authors: Zhang Genhe , Hu Min , Jia Wenyuan , Liu Zhonghua , Li Taotao , Yao Yunshi , Liu Huanjian
Published: April 2021

In order to improve the problems of uneven dispersion, easy agglomeration and insufficient mechanical properties of steel fiber reinforced concrete, vibration mixing and conventional mixing were used to prepare two kinds of test samples. The effects of vibration mixing and conventional mixing on the compressive strength, splitting tensile strength and flexural strength of steel fiber reinforced concrete were compared and analyzed. The results show that, compared with the conventional mixing, vibration mixing compression test can better maintain the integrity of the specimen, only a small number of cracks and small gap, no integral extension cracks appear. Compared with conventional mixing, the average compressive strength of steel fiber concrete for 3d, 7d and 28d under vibration mixing increased by 12.9%, and the splitting strength increased by 12.3%, and the flexural strength increased by 16.8%, and the mechanical properties were strengthened. It provides a reference for the effective application of vibration mixing steel fiber concrete in engineering structure.
Study on Spatial Configuration of Operating Pipe String in Wellbore
Authors: Wang Wenchang , Feng Dajun , Rui Zixiang , Di Qinfeng , Chen Feng
Published: April 2021

The buckling of operation pipe string may occur under complex load in deep well. The serious buckling of the string will lead to partial wear, break or even self-locking, which is detrimental to the downhole operation. At present, most of the studies have focused on the string buckling stability and characteristics of single buckling pattern, and the spatial configuration of entire operation pipe string was seldom studied. In fact, the entire operation pipe string of deep well under complex loads may present a complex configuration consisted of non-buckling, sinusoidal buckling and helical buckling. In this study, the smooth connection condition of different deformation states of pipe string is proposed, and combining the buckling stability analysis and boundary influence characteristics, the spatial configuration of the entire operation pipe string in the borehole could be solved. A field example was given, and the variation of the spatial configuration of the entire operating string with injection pressure is analyzed in detail. The results showed that the calculation method proposed is very useful and important to determine the operation parameters in-situ, to know the working state of the downhole operation string. This works is helpful to avoid the complex situation or accidents in completion practices.
Optimization for Connected Steel Plates of Single-Layer Shaft Wall under Blasting Excavation by Numerical Simulation Method
Authors: Xie Lidong , Gao Xingyuan , Yang Yu , Zhi Youhai , Dong Zhaoxing
Published: April 2021

In order to increase the cross-section utilization rate of the deep shaft, a new type single-layer wall with connected steel plates has been invented. The numerical simulation method is used to analyze the coupling interaction between the steel plate and the concrete. The results show that: there are four vibration strengthening regions in each formwork wall. The order from strength to weakness for the regions is as follows: the concrete outside of vertical steel plate > the concrete at the interface between shaft wall and rock wall > the concrete on the upper side of each formwork > the concrete on the lower side of each formwork. There are two potential leakage channels in the vicinity of the connected steel plate, and the channel under the inclined steel plate is a controlled channel. The thickness of steel plate has an important influence on the damage degree and range of concrete. The concrete damage is affected by vertical steel plate, inclined steel plate and thickness combination of themselves. When the project takes the inclined steel plate 10 mm and the vertical steel plate 6 mm, the phenomenon of crack and leakage of the concrete wall is greatly reduced, and the quality of the project is good.
Application of WBS in Pricing Management of Prefabricated Concrete Construction Project
Authors: Su Jinli , Zheng Xiaolu
Published: April 2021

The standard of measurement and valuation is the main basis for making the bill of quantities and compiling the bidding control price and bidding quotation. In recent years, prefabricated concrete building, as a typical structural form of prefabricated building, has developed rapidly. However, in the actual operation of measuring and pricing of prefabricated concrete construction projects, the existing list system has many shortcomings. Based on this, it is necessary to optimize the measurement specifications of prefabricated concrete buildings in China. At first, this paper USES the principle of the work breakdown structure (WBS) specifications for the measurement of the current prefabricated concrete building structure is analyzed, secondly in jinan city project as an example, to find out its branch, the branch of engineering and engineering subdivisional work on decomposition structure of the preliminary optimization, using WBS to metrological specification for the perfection of prefabricated concrete construction measurement valuation in China to provide the basis.
Research on the Construction Technology for the Reconstruction of Existing Retaining Piles under the Condition of the New and Old Foundation Pits in Close Proximity
Authors: Xie Junkai , Gao Bo , Chen Guanghua
Published: April 2021

In view of the development of the city and the development and utilization of underground space, the new building foundation pit is close to the existing foundation pit. In view of this problem, a common reconstruction technology of existing retaining piles under the condition that the new and old foundation pits are adjacent to each other is proposed. The main construction process includes: primary selection of common pile section, design change, bored pile inspection, construction of steel pipe pile with pilot hole, depth judgment of new and old foundation pit, construction of locking anchor rod, foundation pit construction, monitoring and acceptance, etc. The reconstruction and reuse technology of the existing foundation pit supporting pile has been applied in a foundation pit in Zhuhai, which proves that it is safe and reliable, saves the construction period, reduces the construction difficulty, and improves the construction efficiency, which can provide reference for similar projects.
Study on Mechanical Behavior of Fabricated PC Floor Structure in Construction Engineering
Authors: Lu Qunfu , Zhang Zhengen , Zhou Bingyang
Published: April 2021

In order to obtain the best fabricated floor structure for construction projects, based on the non-linear finite element software ABAQUS, the PC floor and cast-in-place floor slabs of the C30 floor slab scheme of the Jiangyin Jinyi Project were fully simulated. Through the comparison of the two simulation results, it is found that the stress concentration at the center of the cast-in-place floor structure under the full static load is significantly greater than that of the PC floor structure; unlike the uniform force of the PC board, the most vulnerable position of the cast-in-place floor structure is The longer side is not the uniform force of the overall floor structure; after checking the ultimate bearing capacity, strength and deflection of the PC floor structure, it is found that the ultimate bearing capacity of the PC floor structure is 9.187 kN/m and the deflection is 0.049 mm, which are far less than The theoretical value of the design of the floor structure shows that it is feasible to select the PC floor structure in the assembly type of construction engineering, and it is recommended to popularize and apply it in engineering practice.
Strength and Deformation Characteristics of Fiber Reinforced Longdong Loess and Experimental Study of Modified Duncan -Chang Model
Authors: Chu Feng , Luo Jingbo , Yang Wenpeng , Shao Shengjun , Yu Yongtang , Xu Chuanzhao
Published: April 2021

Fiber yarn reinforced loess is prepared through mixing plain loess with a certain proportion of polyester fiber yarn, which is formed by loosening, carding and cutting waste synthetic textile polyester fabric and has rough surface properties and good acid-alkali corrosion resistance. The strength and deformation characteristics of Longdong Loess reinforced by fiber yarn were studied. The test results show that the uniaxial compressive strength of fiber yarn reinforced loess increases with the increase of fiber yarn proportion and fiber yarn length, and decreases with the increase of fiber yarn fineness. Combined with the uniaxial compressive strength data of fiber yarn reinforced loess under the optimal water content and liquid limit water content, an index which can comprehensively reflect the reinforcement performance of fiber yarn reinforced loess is proposed-- Fiber reinforced index. The shear stress-strain relationship of triaxial consolidation drainage of fiber-reinforced loess with different proportion of fiber yarn is strain hardening type. The hypothesis of hyperbolic form is in accordance with Duncan Chang model. By discussing the relationship between the parameters of fiber yarn reinforced loess and plain loess model, the empirical expression of model parameters considering the influence of fiber yarn reinforced loess is obtained. A modified Duncan-Chang E-B model reflecting the influence of different fiber yarn blending ratio was constructed. The rationality of the model is verified by comparing the test curve with the model prediction curve.
Study on Preparation of Saturated Unstructured Loess and Its Strength and Deformation Characteristics
Authors: Chu Feng , Yang Wenpeng , Shao Shengjun
Published: April 2021

In the study of geotechnical damage mechanics, the weighted average of the mechanical deformation states of structurally undamaged and structurally completely damaged soils is used to describe the actual mechanical deformation properties of soils. In the past, when the saturated remolded loess was used to simulate the mechanical deformation of loess, the loess still had some initial structural strength. A method for the preparation of saturated unstructured loess is presented. The strength deformation characteristics of saturated remolded loess were compared by lateral compression test and triaxial shear test. The method of preparing saturated unstructured loess is proved to be reasonable.
Analysis of Low-Temperature Damage of Reinforced Concrete Beams Using Acoustic Emission Parameters
Authors: Li Jianfeng , Ye Zhoujing , Zhao Kang , Yang Zhihao , Gao Zhifei , Wang Linbing
Published: April 2021

Reinforced concrete (RC) beams will be affected by various external environmental in the service process, of which low-temperature is a representative factor. This paper presents a study on using the low-temperature damage test on damage and fracture of RC beams, and an acoustic emission (AE) system is used to monitor the whole process of testing. In the low-temperature damage test, AE hits are used to characterize the damage of each cooling step, and the low-temperature damage of the beam is divided into three processes: initial damage, extended damage and attenuated damage. A damage parameter (DTEM) based on the accumulated energy of AE is used to analyze the whole process of low-temperature damage of the beam, and the percentage of low-temperature damage in each cooling step is obtained. The environment chamber is used to simulate the extreme low-temperature environment, and the damage of RC beam after the sudden temperature drop (process I) and the end of cooling (process II) is obtained. These two processes have important reference value for the damage degree analysis and damage warning of RC beams in the actual extreme low-temperature environment.
Numerical Simulation Analysis of Surrounding Rock Deformation of Expansive Rock Roadway under Humidity Field
Authors: Diao Shichen , Hong Peng , Fu Yu , Mao Xiaobo
Published: April 2021

Based on the measured distribution law of humidity field, according to the humidity stress field theory, the coupling of the humidity field and the ground stress field is realized, and the humidity field is systematically analyzed. Under the conditions, the influence of the expansion of surrounding rock, lining, buried depth, height-span ratio and horizontal pressure coefficient on the deformation of the surrounding rock of the roadway, the general law of the surrounding rock deformation of the swelling rock roadway is obtained. The results show that the five factors have a certain impact on the approaching amount of the two sides of the surrounding rock and the approaching amount of the roof and floor of the swelling rock roadway, but the degree of influence is different. The order of factors affecting the approach of two sides is lining > expansibility > buried depth > horizontal pressure coefficient > height-span ratio; The order of factors affecting the approach of roof and floor is lining > expansibility > height-span ratio > horizontal pressure coefficient > buried depth. The research results provide valuable suggestions and references for the selection of reasonable support schemes and related design and construction of swelling rock roadways.
Deformation and Numerical Simulation Analysis of Deep Foundation Pit Excavation of Nanjing Yangtze River Floodplain Metro Station
Authors: Liu Jiangtao , Nie Meijun , Li Cunjun , Yan Jinpeng
Published: April 2021

Based on the foundation pit excavation construction of a subway station under the soft soil layer of the Nanjing Yangtze River floodplain, Numerical simulation of foundation pit construction process is carried out to study the deformation law of surrounding soil and surrounding structure during foundation pit construction. The research shows that the established finite element numerical model can better predict the structural and stratum deformation caused by the excavation of the foundation pit; the lateral displacement of the ground wall and the ground settlement behind the wall based on different constitutive models are different, but the overall trend is the same. The lateral displacement of the diaphragm wall presents a “bulging” pattern. The surface settlement around the pit shows a settlement trough at a certain distance from the connecting wall. The horizontal displacement of the diaphragm wall increases with the increase of the excavation depth of the foundation pit, and the maximum horizontal displacement occurs above the excavation surface. The conclusions obtained have certain guiding significance for subsequent construction and parameter optimization.
Review on Research Progress and Application of Reinforced Soil
Authors: Cui Meng , Hu Linna , Fu Xiao , Liu Hailin
Published: April 2021

Reinforced soil structure is particularly popular in the field of construction engineering because of its remarkable social, economic and environmental benefits, and is one of the current research hotspots. As a new type of geotechnical structure, reinforced soil has its mechanical characteristic affected by various complex factors, such as the type of reinforced material, the length of the reinforced material, the spacing between the reinforcements, the water content, the drawing directions, the earthquake, the traffic load and so on. Based on studying papers and books, this paper expounds the structural strength characteristic, the interface characteristics and stability of reinforced soil from three aspects, which include basic theory, experimental research and numerical analysis, and the applications of reinforced soil structures in geotechnical engineering are listed. Finally, in view of the current research status and development trend of reinforced soil, the focus and direction that need further research in the future are put forward.
Theoretical Study on One-Dimensional Consolidation of Underconsolidated Marine Clay Induced by Ramp Loading
Authors: Yu Ziye , Wu Wenbing , Zong Mengfan , Zhai Guojun , Xu Meijuan
Published: April 2021

The position of maximum excess pore water pressure is found to be a critical indication in the design of horizontal drainage systems for saturated soil, controlled by the drainage capacity at the boundaries and the self-weight of soil both of which are often ignored. In sea reclamation works, however, the dredged clay used is mostly under consolidated and will undergo the self-weight consolidation. In this paper, an exponentially time-growing drainage boundary condition is adopted, based on which the analytical solution of one-dimensional consolidation of underconsolidated soil under a ramp loading is obtained by using the eigenfunction expansion technique. The obtained solution is verified and a parameter analysis is later carried out. It turns out that when considering the self-weight of the soil subjected to the ramp loading, the variation of the position of maximum excess pore water pressure over time depends heavily on the symmetry of the boundary conditions. The smaller the over consolidation ratio (OCR<1), the shorter the distance of the plane of maximum excess pore water pressure to the bottom surface of the soil layer. Moreover, the larger the loading rate, the higher the plane of maximum excess pore water pressure at the loading stage.
Numerical Analysis of Deep Foundation Pit Excavation Process
Authors: Jiang Xiaoyi , Lu Qingrui , Chen Xiaopeng , Liu Jinling , Li Ping
Published: April 2021

Based on the background of a subway project to be built in a certain city, finite element analysis software Abaqus 6.1.4 was used to simulate and analyze the displacement changes of deep foundation pit excavation, underground diaphragm wall, steel support and other supporting structures. The results show that the maximum horizontal displacement of the diaphragm wall and the vertical displacement (settlement) of soil around the foundation pit occur at the midpoint of the long side of the foundation pit. The maximum horizontal displacement of the underground diaphragm wall reaches 13.9 mm, and the maximum horizontal displacement occurs 16m from the top of the wall. The maximum vertical displacement (settlement) of soil around the foundation pit is 9.5 mm and occurs 8m away from the edge of the foundation pit. For the deep foundation pit with large length and width, the deformation of the middle point and the end section of the long side of the underground diaphragm wall is relatively large compared with other positions, so a reasonable alarm value should be set separately. The axial force of steel support on the excavation layer will increase significantly, which is a focus of close attention in design and construction. The above results can provide some reference for the design and research of deep foundation pit excavation support in soft soil area.
Influence of Shield Tail Clearance on Surface Settlement during Shield Construction in Soft Soil Area
Authors: Li Ping , Lu Qingrui , Chen Xiaopeng , Jiang Xiaoyi , Liu Jinling , Xie Binbin
Published: April 2021

The shield construction process of shield tail gap caused by formation damage, the formation damage caused by the settlement is as long as the part of tunnel subsidence analysis, therefore in the finite element software analysis of shield construction settlement value, the shield tail clearance simulation is an important link in the entire model, this article analyzes three common finite element simulation method, shield tail clearance displacement convergence method based on non-uniform distribution and actual matches are higher than layer such as generation method and stiffness discount subtraction. Finally, the displacement convergence method is used to simulate the grouting effect of shield tail on the surface settlement.
Study on Surface Settlement of Water-Rich Sand Pebble Bed Shield Construction in Nanchang
Authors: Xie Binbin , Lu Qingrui , Chen Shijun , Li Ping , Jiang Xiaoyi , Liu Jinling
Published: April 2021

Water-rich sand layer is a kind of common bad geology that is difficult to control and has great harm. It is easy to cause serious problems such as collapse, water inrush and sand burst, and surface collapse, etc. Through the analysis of shield tunnel of water-rich sand layer in Nanchang city, a numerical model was established to study the influence of different working conditions on surface settlement. The results show that the influence of boundary conditions should be considered more than other soil layers, the influence of different grouting pressures on the surface settlement of the sand and gravel soil layer is not obvious, the surface settlement caused by the water level reduction is greater than that caused by the water level reduction, and increasing the grouting pressure has a certain control effect on the ground settlement after precipitation.
Supporting Condition Evaluation Method of Cable-Stayed Bridges Based on Modal Assurance Criterion
Authors: Ma Yaozong , Zou Qian , Wang Longlin
Published: April 2021

In order to identify the supporting condition of cable-stayed bridges with semi-floating system by using the measured mode shapes, this paper proposed an actual supporting condition evaluation method of cable-stayed bridges based on the indicator of modal assurance criterion (MAC). Firstly, the measured mode shapes and theoretical mode shapes under different supporting conditions could be obtained. Then the corresponding MAC indicator values were calculated, which would be compared to evaluate the supporting condition of bridges. The experiment results revealed that the MAC values between the measured mode shapes and theoretical mode shapes were in good agreement with MAC values above 0.9, which indicated that the actual structural support condition was consistent with the theoretical calculation condition. The experimental results of actual bridges proved that the proposed method in this paper is feasible and effectiveness.
Influence of Subgrade Splicing Mode and Width on Differential Settlement of Pavement Subgrade
Authors: Liu Jiarong , Wang Kai , Cui Shiping , Shu Shiqi
Published: April 2021

In order to study the influence of subgrade splicing mode and width on differential settlement, the large-scale finite element analysis software ANSYS is used to establish the subgrade settlement model, in which the parameters are determined according to the actual subgrade width, widening mode and engineering geological conditions of the widening project of Anxin expressway. The influence of unilateral widening and bilateral widening on the settlement of widened subgrade, the maximum differential settlement on the top of widened subgrade and the influence on horizontal displacement of widened subgrade are systematically evaluated. The results show that for unilateral and bilateral widening, with the increase of widening width, the settlement of the middle line of the old road gradually increases, and the double side widening can make the weight of the widened embankment distribute to both sides of the old subgrade, which greatly improves the settlement coordination of the old and new Subgrade, and is beneficial to the stress of the pavement structure.
Experimental Study on the Characteristics of Air Voids of Asphalt Mixture under Vacuum Compaction
Authors: Hu Min , Jia Wenyuan , Liu Zhonghua , Zhang Jianxiong , Yao Yunshi , Shen Zhenzong
Published: April 2021

In order to improve the compaction quality of asphalt mixture, a vacuum compaction technology is studied. Under different vacuum degrees (0 MPa, -0.04 MPa, -0.06 MPa, -0.08 MPa and negative pressure), the vacuum compaction process was used to prepare asphalt mixture samples and their characteristics of air voids were tested. The test results show, when the vacuum degree increases from 0 to -0.08 MPa, the air voids decrease with the increase of vacuum degree. The middle and upper air voids are small, and between 9-25 layers, average air voids under vacuum degree of -0.08 MPa and negative pressure is 13.2%, which is 41.6% lower than that under non vacuum; The average diameter is controlled at 1.88∼2.19 mm under vacuum degree of 0.08 MPa and negative pressure, which is 43.3% less than that under non vacuum. Those results show that vacuum compaction can effectively improve the characteristics of micro air voids of asphalt mixture, which will also improve the compactness.
Experimental Study on Interlayer Mechanical Properties of Semi-Rigid Base Asphalt Pavement Using Interlayer Treatment Method
Authors: Jia Wenyuan , Hu Min , Liu Zhonghua , Li Taotao , Chen Shibin , Gao Jun
Published: April 2021

In order to improve the interlaminar mechanical properties of semi-rigid layer and asphalt layer in asphalt pavement, the method of the base surface treated pits was studied and their properties at different temperatures were explored. The experimental results show that at 20 °C, compared with the base surface untreated, the interlayer shear strength of the base surface treated 9 pits of q>20 mm was increased by 27.95%, and the tensile strength was increased by 57.51%. Within a certain range, increasing the diameters of the pits can improve the bonding effect between the layers. In the temperature range of 0 °C-40 °C, the interlayer bonding effect of the base surface treated 9 pits of q>20 mm and spread oil is been better than the other three interlayer treatment methods in the experiment. These results show that the base surface treated the pits can form mortise structure, which can improve the mechanical properties between layers and weaken the negative effect of high temperature on the adhesion between layers.
Research on Application of Chinese Codes in Asphalt Pavement Design of French Speaking Countries
Authors: Tang En-kuan , Cai Kang , Qu Lian-feng , Zhang Run-yao , Zhang Peng
Published: April 2021

In this paper, based on the calculation of asphalt pavement of North-South Expressway in Algeria, the applicability of Chinese code in asphalt pavement design of French speaking countries is studied. Although there are differences in pavement design methods between China and France, by adjusting the pavement design parameters and asphalt mixture, it can be transformed into representative indicators applicable to the Chinese code in a targeted manner. The Chinese code was used to design and check the asphalt pavement of the North-South Expressway in Algeria. The results show that it is feasible to design asphalt pavement in French speaking countries by using Chinese codes, which provides basis and reference for the application of Chinese codes in French speaking countries.
Disease Analysis for “Single Plate Bearing” in Plate Girder Bridge and Its Strengthening Scheme
Authors: Zhao Man , Li Yiqiang
Published: April 2021

The phenomenon of “single plate bearing” is one of the diseases in plate girder bridges. In order to study its mechanical characteristics and strengthening schemes, with the help of finite element software ANSYS, “single plate bearing” of plate girder bridge is simulated numerically in this section. Firstly, models are simulated with beam element, and transversal distribution rule of load is analysed. Then according to the mechanical behavior of plate girder bridge and the reason leading to “single plate bearing”, five strengthening schemes are proposed to delay or avoid “single plate bearing” and their spatial models are built with solid element Mechanical behaviors such as displacement, stress are contrasted and analysed. Furthermore, transversal stress at hinged joints is analysed in detail, and it is proposed that the adhesive strength between new and old concrete should be applied to test transversal stress at hinged joints. At last according to the merit and demerit of five strengthening schemes, feasible schemes for “single plate bearing” are given.
The Formation Mechanisms of Road Traffic Noise in Urban Historic Districts: A Case Study of Grand Tang Dynasty Ever-Bright Block in Xi’an, China
Authors: Ding Xin , Li Bofeng , Zhang Qi
Published: April 2021

The formation mechanisms of road traffic noise in urban historic districts are comprehensively studied through analyzing the superposition of influencing factors with the characteristics of historical districts. Then both the gray related theory and spatial syntax theory are used to construct the screening method of road traffic noise causes which can combine accurate quantitative data and spatial structure selection probability, while the empirical study of Grand Tang Dynasty Ever-bright block in Xi’an is conducted then. The research indicates that the formation mechanisms of road traffic noise in urban historical districts are due to complex stratification in which the traffic flow of motor vehicles, non-motor vehicles and pedestrians affect the noise formation by individual or as a whole under different conditions, as well as the disturbances of landscape nodes and road attributes. Moreover, it is believed that accurate identification of non-quantitative factors is the key to design road traffic noise screening method in historical districts rather than motor vehicle traffic flows.