bluuebunny/crossref_metadata_2025 huggingface dataset:
Influence of Particle Shape on Mechanical Properties of Coal Measure Soil by Discrete Element Method
Authors: Zhang Bang , Feng Haoran , Zhang Hong
Published: March 2020

On the basis of the discrete element theory, PFC3D was used to generate five particle models of different shapes. The impacts of particle shape on the macroscopic physical and mechanical properties of soil mass were analyzed through the numerical simulation of triaxial test as well as from a microscopic point of view. The results showed that the shear strength of irregularly shaped particles is higher than that of spherical particles, and that among the irregularly shaped particles, the shear strength of cylindrical particles is higher than that of ellipsoidal particles. Since spherical particles are associated with relatively large rotation angles during loading, samples have obvious dilatancy. However, among the irregularly shaped particles, since the inter-particular interlocking is strong and the rotation angles are relatively small, samples does not display significant dilatancy. The more irregular is the particle shape, the greater will be the energy dissipated by damping, indicating that the lesser is the kinetic energy stored in samples, the less likely the particles will move, and the more stable the sample will be.
Strength of Cement Mortar Solidified Soil and Prediction
Authors: Wang M , Yang J J , Zhao M Q , Liu H , Li S C
Published: March 2020

Strength is an important index to evaluate the solidification effect of cement soil and engineering design and construction inspection. The unconfined compressive strength test of cement mortar solidified soil was carried out. The results showed that the strength growth rate of cement mortar solidified soil increased linearly with the sand content, which was the maximum at 7d, and tended to be stable after 14d. The strength of solidified soil increased with age, and the initial growth rate was relatively fast. Compared with cement soil, the coefficient of deformation of cement mortar solidified soil did not slow down obviously in the later period. Taking cement mortar solidified soil as cement soil for strength calculation, the strength prediction equation of cement solidified soft soil at full age could well reflect the strength growth rule of cement mortar solidified soil.
Standardization and Diversification of Precast Concrete Facade Panel
Authors: Li Feng , She Long , Wang Huan
Published: March 2020

Standardization is a major feature of the performance of fabricated building facades, which can achieve high-efficiency construction, reduce costs, and simplify production and construction difficulties. However, excessive standardization restricts the diversification of facades. Through a comparative study of Chinese and foreign completed cases, we seek a balance between standardization and diversification, avoid the limitation on facade diversification of standardization, explore performance potential of precast concrete facade panel in China, and achieve the integration of standardization and diversification of precast concrete facade panel.
Review on The Progress of Expansive Soil Improvement in Ten Years
Authors: Pan Yaosen , Li Mingdong , Dai Renhui
Published: March 2020

In the past ten years, due to the property of expansive soil foundation is worse than the general foundation, a series of new problems have been encountered in the improvement treatment, and the research and solution of these new problems have promoted the sustainable development of technology. The characteristics of various methods and their effects on the improvement effect were summarized. Soil displacement is suitable for projects with high engineering requirements and thin expansive soil layer. For projects with weak expansive soil improvement and high environmental protection requirements, fiber improvement and wind-blown sand improvement can be adopted. The longer the curing period, the better the lime improvement effect. The solid waste improvement should be adopted according to the local waste situation. When the effect of single improvement is not good, compound method can be adopted.
Experimental Studies on Thermo-mechanical Coupled Behavior of Pile-Clay Interface
Authors: Wang Jingkai , Zhang Zhichao
Published: March 2020

The thermo-mechanical coupled behavior of pile-soil interface is very important for the mechanical performance of energy pile. It is studied in this paper by the thermo-mechanical coupled direct shear tests with a temperature controllable concrete specimen in the top shear box and a Kaolin clay specimen in the bottom shear box. The results show that the strength of pile-clay interface significantly depends on the temperature, the temperature cycle number and the over-consolidation ratios of clay. With the heating-cooling cycles, the interface strength can increase and decrease monotonically or non-monotonically depending on the stress state and history of clay, which is generally a thermo-elasto-plastic process. It is shown that the thermo-mechanical coupled pile-clay interface behavior is the net effect of the pore water transportation and the rearrangement of clay particles near the interface as well as the thermal consolidation/expansion of clay.
Effects of Random Variations of Partially Saturated Soils Properties on Site Amplification of Seismic Ground Motions
Authors: Xie Jiang , LI Dan
Published: March 2020

Based on the principle of random vibration and the Tajimi-Kanai spectrum model, a seismic model with a given magnitude and epicenter distance is used to simulate the seismic motion. For the random variation of soil properties such as shear modulus, mass density, damping ratio and saturation of partially saturated soils, it is assumed that the input seismic wave is SH wave. The random dynamic response analysis of the site is conducted by using the linear wave propagation method and the Rosenblueth method, and the digital features of the amplified power spectral density function, the acceleration power spectrum density, the mean value and the standard deviation are obtained respectively. In a numerical example, a clay ground is considered. For the random variation of soil properties and the different of incident angles, the digital features of the amplified power spectral density function, the acceleration power spectral density, the mean value and the standard deviation are analyzed. The results show that the random variation of quasi saturated soils properties and the different of incident angles have great influence on the site amplification effect.
Stability Evaluation of Concrete Structure Considering the Local Damage Using Nondestructive Detection and Numerical Analysis
Authors: Tan Xuyan , Chen Weizhong , Yang Jianping , Wang Luyu
Published: March 2020

Shield tunneling is one of the most important technologies for building of underground engineering. Many grouting holes were prefabricated for the requirement of backfill grouting, which is easy to induce local damages and potential disasters, such as leakage and cracking. Accordingly, an integrated workflow for damage detection and stability evaluation was performed based on nondestructive testing (NDT) and numerical simulation. As a case study, this method was applied to an underwater shield tunnel. Firstly, Ground Penetrating Radar (GPR) was used to detect the conditions in grouting holes. Then, the infrared camera was used to determine the damaged positions induced by grouting holes. According to NDT results, the numerical models were developed to analyze the mechanical behaviors of structure. It indicated the geophysical inversion results are consistent with field conditions. The influence area increases with a significant value of water pressure, and stress magnitude would increase to 45KPa if the increment of water pressure reaches to 10KPa. As a promising application, structure stability was evaluated in the light of analytical results.
The Study of Slope Protection with Gravel-Polymer Composite Porous Material
Authors: Xu Yi , Wang Jun , Wang Maomei , Zhao Gang , Xu Tianhang
Published: March 2020

In this study, strength reduction method, steady state analysis and transient analysis are used to simulate and compare the stability and permeability characteristic of bank slope in three different states: natural, slope protection with concrete and slope protection with gravel-polymer composite material. The result show that the slope with protective surface is more prone to shallow shear failure than the bank slope in natural state and their stability is reduced. For the bank slope of slope protection with gravel-polymer composite material, the appropriate thickness of the surface layer should be selected to give full play to the bending performance. In terms of permeability characteristics, slope protection with gravel-polymer composite material has good permeability and it is more difficult to destroy by percolation when the water level drops rapidly.
Effect of Quality and Replacement Rate on the Double Recycled Aggregate Concrete
Authors: Guo Yuanxin , Li Qiuyi , Yue Gongbing , Zheng Shidong , Wang Liang
Published: March 2020

Recycled aggregate can be used as a substitute for natural aggregate to produce good regenerated concrete, so the text use recycled coarse aggregate and recycled fine aggregate to substitute for natural aggregate with different replacement rates preparing double recycled aggregate concrete, and researching the effect of the quality and replacement rate of recycled aggregate on the mechanical properties of recycled aggregate systematically. The results show that the compressive strength of double recycled aggregate concrete is increased gradually with the improvement of the quality of recycled aggregate, and the effect from weak to strong is class I, class II and class III. On the other hand, the compressive strength of double recycled aggregate concrete is decreased gradually with the increase of the replacement rate of recycled aggregate, and the maximum reduction is up to 57.2%. Therefore, the simultaneous use of recycled coarse aggregate and recycled fine aggregate have an effect of “double weakening” on the compressive strength of recycled concrete, and it can be applied to the concrete products of low strength grade.
Study on Drying Shrinkage Deformation of Metro Lining Concrete
Authors: Gao Song , Wang Shouhui , Li Qiuyi , Yin Xianfeng , Zhou Guiyin , Guo Yuanxin
Published: March 2020

In metro engineering, due to the large amount of lining concrete pouring, it is easy to produce large shrinkage deformation in the maintenance stage, which leads to cracks in lining concrete and seriously affects the operation and safety of metro. Therefore, this paper adopts the test scheme of large dosage of mineral admixtures to compare and analyze the influence of the amount of cementing material, the dosage of mineral admixtures and the binder/water ratio on the dry shrinkage performance of metro lining concrete. The results show that the shrinkage ratio of lining concrete increases with the increase of cementitious material content or binder/water ratio, but decreases with the increase of the dosage of mineral admixtures. When the cement variety is P.I 42.5 and the dosage of mineral admixture is 40%, or the cement variety is P.I 52.5 and the dosage of mineral admixture is 50%, the shrinkage deformation of lining concrete is small, which can meet the needs of subway construction and will have a broad application prospect in practical engineering.
The Threshold Value of Effective Replacement Ratio of Fly Ash Mortar Based on Amount of Calcium Hydroxide
Authors: Liu Guibin , Guo Yuanxin , Li Qiuyi , Wang Liang
Published: March 2020

The effective mineral admixture in mortar can consume the calcium hydroxide produced by hydration reaction because of pozzolanic effect. For high volume mineral admixture mortar, when the replacement ratio exceeds a certain ‘threshold’ value, the supply of Ca(OH)2 amount is insufficient, the superfluous and ineffective mineral admixture will no longer react in mortar but as fine aggregate. This study presents an experiment study on the threshold value of effective replacement ratio of fly ash mortar by the comprehensive analysis of Ca(OH)2 amount and consumption curves. Under the conditions of different curing temperature, the effective replacement ratios of fly ash mortar have been determined ultimately. The results showed that Ca(OH)2 amount and consumption in mortar both decreased with replacement ratio. For fly ash mortar, at 20°C curing temperature, when the replacement ratio was less than 40%, the Ca(OH)2 amount decreased obviously with replacement ratio. However, when replacement ratio was more than 40%, Ca(OH)2 amount at 91d changed slightly with replacement ratio, the Ca(OH)2 amount was consumed to a limit value at this time. Under the condition of 30°C curing temperature, when the replacement ratio exceeded 30%, the change of Ca(OH)2 amount with replacement ratio was close to a straight line, the superfluous fly ash no longer consumed Ca(OH)2 basically. Moreover, the consumption of Ca(OH)2 was not much difference to the Ca(OH)2 amount at the same replacement ratio under the condition of 20°C curing temperature. This result has a great significance on effective utilization of mineral admixtures in engineering application.
Research on Dynamic Perception Algorithm for High Speed Maglev Track Irregularity
Authors: Ding Sansan , Jiang Fujie , Sun Xiangdong , Huang Jingyu , Li Dongshuai , Li Huibai
Published: March 2020

The high-speed maglev track irregularity is an important factor affecting the safety and stability of high-speed maglev trains. Based on the basic principle of high-speed maglev vehicle orbit, the deep neural network is used to establish the relationship between the vibration acceleration of the vehicle body and the track irregularity, so as to realize the real vehicle detection of the track irregularity. The results show that the relative error of the prediction of the track irregularity by the deep neural network is 6.04%, which basically meets the actual measurement requirements in the project. At the same time, it is demonstrated that the model with 8 input nodes has higher prediction accuracy and the high-speed maglev track is not smooth. Measurement provides theoretical support.
Studies on Vibration Response of the Continuous Girder Highway Bridge under Horizontal Multi-Vehicle Loads
Authors: Chen S S , Luo H , Song Y
Published: March 2020

In order to study the vibration response of continuous girder bridges under horizontal multi-vehicle loads, we used ANSYS to build the three-dimensional solid finite element model of continuous girder highway bridge, simulated three-axis self-dumping truck by three-dimensional models, and considered the impact of road roughness to establish the multiple vehicle-bridge coupled vibration equation. We studied the vibration response of bridges under the horizontal two-vehicle, longitudinal two-vehicle and single-vehicle conditions by running MATLAB program. The result shows that the impact coefficients of the bridge under horizontal two-vehicle condition are close to that of single-vehicle condition, and the impact coefficients of the bridge under longitudinal two-vehicle condition fluctuate around that under single-vehicle condition. The vibration response of the bridge under multi-row vehicle loads is related to various factors such as vehicle velocity, bridge span, vehicle spacing, and the quality level of the bridge surface.
Construction Quality Evaluation Framework of CRTS I Double-Block Ballastless Track Applied in Chinese High-Speed Railway: Based on AHP and Fuzzy Extension Element-Matter Model
Authors: Chen Huihua , Li Na , Li Hujun , Mei Min , Tang Rujia
Published: March 2020

The construction quality of CRTS-I double block ballastless track (CRTS-I-DBBT) is the basis of ensuring the comfort, safety and durability of high-speed railway, which helps to promote sustainable development of high-speed railway. This research constructs a quality evaluation framework for CRTS-I-DBBT construction. AHP and Fuzzy Extension Element-matter model were integrated to evaluate the construction quality of CRTS-I-DBBT. Besides, empirical research was carried out to test the applicability of the proposed evaluation system. Besides, the evaluation system will have a wide range of applicability and it will help facilitate the maturation of high-speed railway ballastless track construction quality management.
Intelligent Integral Improvement Technology of Double Block Sleeper Production Line of Zheng-wan High-Speed Railway
Authors: Wang Minghui , Wang Jian , Zhang Qiao
Published: March 2020

Double block sleeper is an important part of high-speed railway. Relying on the sk-2 double-block sleeper production line of Chongqing section in Zhengwan high-speed railway, a set of intelligent integrated lifting sleeper production technology system is designed and put into use. The system provides a safe operation platform for the operators to ensure the production schedule, reduce labor intensity, save costs, improve economic benefits, and has great promotion value.
Stability Analysis of Hollow Thin-Walled High Pier Curved Bridge Without Diaphragms
Authors: Xiang Musheng , Wang Ge , Peng Longfan
Published: March 2020

As the height of bridge increases, more and more high piers are designed with diaphragms to ensure their stability. However, the insertion of the diaphragms will have a significant impact on the speed and efficiency of the pier construction. For the stability problem of hollow thin-walled high piers, the numerical simulation of the model with or without diaphragms is carried out to compare and analyze the force mode, ultimate bearing coefficient and deformation characteristics of high pier of curved bridge from the perspectives of full bridge buckling analysis, high pier integral stability and high pier local stability in this paper. Studies have shown that the effect of installing concrete diaphragms on the stability of such single hollow thin-walled high piers is not obvious. If the wall thickness of the high pier meets the requirements for strength and stiffness and the theoretically calculated maximum allowable width-to-thickness ratio, the long-span continuous rigid frame curved bridge high piers may not be provided with diaphragms.
Numerical Analysis of Wind Loads on Bridges in Sandy Environment
Authors: Jia Ying , Zhan Mei , Zhang Yahui
Published: March 2020

Based on the Euler two-phase model, sand is regarded as a flowing fluid. In the numerical analysis, the sand is simulated as two-phase flow. Wind load variation on the windward side of the bridge under the wind-blown environment is analyzed numerically. Wind load variation on the bridge is studied when the flow velocity, particle size, and sediment concentration are different. This paper’s wind load numerical analysis is compared with the wind load calculated in the Code for Wind Resistance Design of Highway Bridges. Results show that the effect of sand load under wind and sand environment cannot be ignored.
Research on the Application of Full Space Support Construction Technology in Frame Bridge Construction
Authors: Chen Tao
Published: March 2020

The cast-in-situ construction of full space support is a traditional beam bridge construction method. Because of its advantages of simple structure, convenient disassembly, assembly, and transportation, etc., the construction technology of full space support is applied more and more widely. The control of support erection in the construction process plays a key role in the formation of the bridge. Based on the practical experience, this paper makes a detailed study on the construction technology of cast-in-situ bowl-buckle full space support.
Feasibility Study on Application of Full Depth Asphalt Pavement in National Trunk Road
Authors: Yan Xiangpeng , An Ping , Wu Wenjuan , Wang Lin , Wei Jincheng
Published: March 2020

Axial load spectrum survey was carried out on site, and the analysis and calculation of the structure design of full depth asphalt pavement was carried out according to the actual traffic volume. The permanent deformation of the asphalt mixture layer, fatigue cracking of the asphalt mixture, inspection and analysis of design indicators were verified. The test road was paved, and the feasibility of the application of the full depth asphalt pavement in the national and provincial roads was verified through the comparison between the actual measured deflection and the theoretical calculated deflection. The results show that the traffic load level of ordinary national and provincial roads reached the heavy traffic level. The service life of full depth pavement structure calculated can reach more than 40 years. And the designed service life of permanent deformation can reach more than 15 years. The actual measured deflection of the test road satisfies the calculated deflection values of both the subgrade top surface and road surface. The full depth asphalt pavement structure is applicable to national and provincial trunk lines under heavy traffic load conditions.
Study on Dust Movement in Long Tunnel during Blasting Period
Authors: Wang Qingbiao , Ren Guohui , Shi Zhenyue
Published: March 2020

In order to solve problems raised tunnel ventilation and dust removal, grew up in this paper, the tunnel blasting dust migration rule, through theoretical analysis, experiment on site and numerical simulation of the synthetic study method, study of phase grew up in the tunnel blasting dust migration rule, the conclusion is as follows: (1) Based on fluid mechanics, mechanics of elasticity theory, and combining the fick’s second law, in the initial conditions and boundary conditions, that along the longitudinal tunnel dust unsteady diffusion distribution; (2) The experiment found that the dust concentration decreased gradually with the increase of ventilation time, and the dust accumulated with the increase of distance from the palm surface. The dust in the same section was mainly distributed in the arch waist and below, with obvious stratification. (3) By comparing the numerical simulation with the field monitoring data in FLUENT, the accuracy of the numerical simulation results was verified, which provided theoretical guidance for tunnel construction and dust removal design.
Numerical Experiment for Support Effect of Umbrella Arch in Tunnel
Authors: Wang Yuwen , Hu Zhao , Xie Yongli , Wang Chao , Hua Kaicheng , Lai Jinxing , Lai Hongpeng
Published: March 2020

Umbrella arch is often used as pre-support for shallow tunnel and poor surrounding rock. To evaluate the support effect quantitatively, 12 cases by numerical analysis were used to study the effect of cover depth and condition of surrounding rock on the support effect of umbrella arch. Load percentage of umbrella arch was proposed to evaluate the effectiveness of umbrella arch. The umbrella arch could not work when the percentage was less than 50%. When the surrounding rock was poor and the shallower the cover depth, the better the support effect.
Research on Surface Settlement of Subway Station Construction Using Pile-Beam-Arch Approach
Authors: Xu Yushan , Tang Bo , Duan Yanwei
Published: March 2020

The pile-beam-arch (PBA) approach is illustrated as a creative construction method in shallow-buried tunneling excavation of subway construction. Attentions have been paid to this method due to its unique advantages of construction technology. Subway station construction by using PBA approach will make disturbance to the ground surface. Research on surface deformation caused by PBA approach is of great significance to the surrounding environment and its structure. The example of subway construction in Beijing is presented as the research background, a three-dimensional model is established by using the Midas-GTS finite element numerical simulation software to simulate the practical excavation support conditions, and to analyze the surface settlement, the initial support structure settlement and crustal stress caused by PBA construction method.
Research on Assembly Waterproofing Technology of Prefabricated Utility Tunnel
Authors: Li Liangcheng , Lu Tian , Jia Rubin , Li Yuanyuan , Zhou Wenyan , Khater Ahmed , Luo Dong
Published: March 2020

Prefabricated utility tunnel is the key development direction of urban infrastructure in the future because of its greater advantages of quality, construction period, cost and other aspects, compared with cast-in-place method. For prefabricated utility tunnel, both of joint type and waterproofing construction could directly affect its function and normal operation. This paper introduces main types of prefabricated utility tunnels, and compares the performance of frequently-used waterproof materials. Meanwhile, the existing waterproof projects in prefabricated utility tunnel are summarized and analyzed, and the development trend of assembly waterproofing technology in the future is prospected based on the above research.
Study on the Layering Length in a Railway Tunnel with Semi-transverse Extraction Ventilation
Authors: Tu Jiachao , Bi Haiquan , Wang Honglin
Published: March 2020

In this study, the long-distance subway tunnel in Qingdao of China adopted semi-transverse extraction ventilation is taken as the research object. STAR-CCM+ software is used to simulate the smoke movement status and study the influence of different exhaust volumetric flow and heat release rates on the smoke layering length in tunnel with the semi-transverse extraction ventilation. Results show that the layering length has a linear decreasing relation with the natural logarithm of the exhaust volumetric flow under different heat release rates. There is opposite relation between the layering length and the natural logarithm of the heat release rate. Based on dimensional analysis and numerical simulations, the prediction model of the layering length and the critical exhaust volumetric flow in tunnel with semi-transverse extraction ventilation is proposed.
Numerical Simulation Analysis on the Supporting Effect of Different Pre-reinforcement Methods in Portal Section of the Shallow Buried Soft Rock Tunnel
Authors: Shi Shaohua
Published: March 2020

The surrounding rock of shallow buried soft rock tunnel has already been weathered severely, which has a large number of fracture zone, so construction of these tunnel projects is difficult and risk. The tunnel is vulnerable to deformation and collapse during the construction especially in the portal section, so certain advanced support must be used to ensure the tunnel excavation smoothly. Base on the Xikema no.1 tunnel engineering, the numerical simulation using finite difference software (the FLAC3D) was conducted in this paper to model different excavation with pipe-roof and double-row small duct advanced support in the portal section. Some meanful conclusions are drawn by comparative analyzing the support effects of pipe-roof and double-row small duct through stress, displacement, plastic zone of surrounding rock, and inner force of primary support, such as follows: (1) Pipe-roof or double-row small duct advanced support and surrounding rock can form into a complex well, which play a role of load-bearing arch. The complex effectively reduce the disturbance of upper rock, and commendably control the relaxation of surrounding rock in the vault, but for arch feet and arch bottom the control effect is not ideal. (2) Pipe-roof or double-row small duct advanced support make primary support and surrounding rock of tunnel face only beared the deformation pressure caused by the deformation of complex, effectively improve the safety of primary support and tunnel face. The research result will be useful for the design and construction of the pre-reinforcement measure to the project associated.
Numerical Analysis And Research of Entrance Slope of Shallow Buried Karst Tunnel
Authors: Zhong Tao , Ma Qun
Published: March 2020

Based on practical engineering condition of Highway karst tunnel, ANSYS was used to numerical simulate the slope of the tunnel in the entrance, and the result was used to compare with monitoring measurement result. The numerical simulation results showed that the bottom karst cave has a big influence on arc bottom of the tunnel after the excavation. The most influenced part is vault, with 2 times tunnel diameter influence area to the tunnel. At the first 35 m of excavation, there is a relatively greater influence to slope, and measures should be taken; after 35 m of excavation, there is little influence to slope. The result can be a reference to the design, construction and research of the tunnel.
The Calculation Method of Energy Consumption of Air-Conditioning System in Subway Vehicle Based on Representative Operating Points
Authors: Li Ce , Wang Honglin , Bi Haiquan
Published: March 2020

In order to study the standard energy consumption of air-conditioning system of subway vehicle and optimize the performance of air-conditioning system, it is necessary to clarify the air-conditioning representative operating conditions. In this paper, based on the tested data during real operation of subway vehicle in summer, the characteristics of the air-conditioning operating conditions are analyzed, and the construction method of the operating conditions is first proposed. Secondly, taking the tested line as an example, using the constructed operating conditions as sample data, the k-means clustering algorithm is used to identify the representative operating points of the air-conditioning in the cooling season. Finally, the energy consumption based on the representative operating points of the cooling season is calculated by LMS AMEsim software, the error between calculated results and field measurements data is within 10%, which verifies the accuracy of energy consumption calculation method based on these representative operating points.
Influence of Water and Sediment Conditions on Flow Path into Sea Movement in the Huanghe Estuary
Authors: Huang Libing
Published: March 2020

For researching the laws of flow path into sea movement in siltladen rivers, according to the measured topographic data since 1976 to 2015, it analyses the course of the flow path movement during in Qingshuigou path in Huanghe estuary. The results show that current flow paths deposits and extends controlled by runoffs and ocean hydrodynamics. The old flow paths are eroded and dominated by ocean power. The runoffs and sediment into sea reduce by 42% and 78% after 1996, respectively. As a result, the averaged deposition rate reduces by 81%. The avulsion rate of the flow path into sea is also decreased.
Influence of Rainfall Infiltration on Transient Volumetric Water Content of Coal Measure Soil Slope
Authors: Liao Wei , Lin Junbo , Zhang Hong
Published: March 2020

With coal measure soil side slope in Jiangxi’s Pingxiang-Lianhua Expressway selected as the research object, GeoStudio, a finite element seepage analysis application, was adopted for numerical simulation on the variation pattern of volumetric moisture content in the side slope in rainfall as well as its spatial distribution characteristics. The results show that rainfall infiltration mainly influences the surface layer of the side slope and that its influence decreases with the increase of depth. The volumetric moisture content of undisturbed coal measure soil remains basically unchanged under the weathered layer. When soil mass permeability coefficient is less than rainfall intensity, the rainwater permeates quickly in the outermost layer of a weathering zone, but exerts a minor influence. When it is larger than the rainfall intensity, rainfall permeates slowly but exerts a major influence. When rainfall intensity reaches 8.33 ×10−7 m/s, soil moisture contents in the superficial layers of the slope toe and halfway up the slope surface become saturated. The saturation depth is 80% of the weathered layer. When the rainfall intensity reaches 1.1 ×10−6 m/s, it exerts a more extensive influence on the saturation area in the side slope, but the corresponding affected depth is only 50% of that in the weathered layer.
Discussion on the Delimitation of Main River in Anji County under the System of River Chief
Authors: Zhou Jiahong , Chen Qi , Han Haiqian
Published: March 2020

The river chief system has been advanced in all respects, river management is an important part of river chief system. River demarcation refers to the demarcation of river shoreline and the scope of management and protection, which is the premise of water management. Based on the analysis of the present situation, management and demarcation of the river in Anji County, the article puts forward the management problem and necessity of the demarcation of the current situation of the river in Anji County, and puts forward the principles and methods of the demarcation of the river shoreline and the scope of management protection according to different types.
Study on Sedimentation Characteristics and Reduction Measures of Bajiazui Reservoir
Authors: Jiang Chao , Wei Guoliang , Fan Leiran , Zu Anjun
Published: March 2020

The Bajiazui Reservoir is located at the middle section of the Puhe River, a tributary of the Jinghe River. Sediment deposited in the reservoir in a cone shape. The floodplain in the reservoir area is wide and sediment deposited horizontally. In recent years, sedimentation in the Bajiazui Reservoir has consumed 70% of the total storage capacity. As a consequence, the storage capacity has been severely lost, and the operation of reservoirs has become increasingly difficult. The water supply in the Xifeng urban area is getting worse. According to the sedimentation characteristics of the reservoir, an operation method is proposed that the reservoir adopts the operation mode of “storing clear and releasing muddy, emptying reservoir to drain flood” in the normal operation period. Dispatching control conditions are also given to achieve releasing sediment from the reservoir throughout the year during the flooding period, and to achieve a relative balance of erosion and deposition in the reservoir area.
A Review on the Physical Dewatering Methods of Sludge Pretreatment in Recent Ten Years
Authors: Zhen Zheng , Jinxiang Yi , Renhui Dai
Published: March 2020

Due to the increasingly tight land resources and the increasingly intensified ecological environment of pollution, sludge treatment has become an important subject of environmental protection research, among which sludge dewatering is the primary link of sludge treatment. Many researchers have used physical methods to improve the dewatering performance of sludge. Through the distribution of sludge water, this paper analyzes the influence of several important factors of sludge dewatering, and expounds several methods for sludge dewatering pretreatment such as electrolysis, freezing and thawing method, ultrasonic method and activated carbon adsorption method and corresponding dehydration mechanism such as change the sludge particle size, increase the sludge water channel, shatter extracellular polymers and change the charge distribution of sludge.
Flume Test on the Movement Characteristics of Pipeline Oil Spill under Water
Authors: Xiao Hui , Yang Zhiwen
Published: March 2020

In order to understand the movement process and characteristics of oil spill in submarine pipeline, a model test is carried out in the flume. The movement process and shape of oil spill from underwater to water surface are observed through experiments. The relationship between the characteristics of oil spill such as rise time, average movement speed of oil particles at representative point and oil spill diffusion width with different oil spill volume and different flow velocity is analyzed. The experimental results can provide a reference for the oil spill trajectory research and diffusion numerical simulation.
Improve the Luminous Environment in a Classroom
Authors: Liu Guodan , Li Hanlin , Kang Yunxing
Published: March 2020

This paper suggests a lighting design method by advanced software to design for optimizing the luminous environment in a classroom. The luminous environment affects the eyesight health and learning efficiency of students, while uncomfortable glare is an important indicator that affects the quality of classroom light environment. This paper describes the evaluation method of uncomfortable glare, and select a typical classroom light environment field survey and subjective questionnaire survey, which puts forward the optimization and improvement of the lighting layout scheme, and uses DIALux simulation analysis to simulate the illuminance and glare values of different schemes. The findings support the classroom installation of grille lampshades and LED lamps not only meet lighting requirements, can effectively reduce the impact of glare and benefit designers in the strategic design process with further potential for design options and lighting electricity reduction.
Research on Pre-Grouting Technique of Blind Shaft of Metal Mine in Southwest China
Authors: He Wen , Gao Xiaogeng , Feng Xuhai
Published: March 2020

In order to ensure the safe and rapid excavation of the shaft, the blind shaft of MAO PING mine was treated by pre-grouting. The “S” borehole directional drilling was used, and the clay cement grout was selected as the grouting material. After the completion of the construction, the remaining water inflow of the shaft grouting section was measured to be 4.83m3/h by water pressure test. The blind shaft pre-grouting project has been successfully implemented, and its design and construction technology have important guiding significance for the application of water prevention and control in mining areas which located in southwest China.
Investigation and Analysis of Old Houses’ Aseismic Capability in Rural Areas of Jiangxi Province
Authors: Zhou Qiang , Zhao Wenyang , Yang Lingyu , Song Guquan
Published: March 2020

Villages and towns are the most earthquake-prone areas in China, due to the backward economic conditions and the lack of aseismic awareness of residents in rural areas, earthquake damage in these areas tend to be severe. In order to understand the aseismic capability of old houses better in rural areas of Jiangxi province, investigation was carried out in numerous counties of Jiangxi. The structural types, construction time and aseismic construction defects of the old houses were mainly investigated; besides, in view of the old houses’ aseismic construction deficiencies, combined with the existing research, the methods and countermeasures for enhancing the aseismic capability of old houses are given.
Based on the characteristic of different Spaces, the pattern of plant landscape in universities
Authors: Huang Yi , Li Chun , Zhang Le
Published: March 2020

With the rapid development of our social economy and culture, the importance of higher education is growing. A large number of enrollment expansion of colleges and universities across the country, the teaching scale expands unceasingly, also a lot of the old campus and facilities can not support their enrolment, affect the quality of teaching. Therefore, the construction of new campus, rebuilding the old campus is the top priority. At the same time, building a harmonious society in our country, under the premise of ecological environmental protection, and others put forward constructing the campus “urbanization”, “ecological campus”, so it is particularly important to reasonable planning campus construction[1].

Beautiful environment landscape is the spirit of the campus construction, institutions of higher learning campus landscape should have four main functions, namely: meet the needs of the employee’s work and life between teachers and students, by the spirit of good environment edify people sentiment (“people create environment and conditions for people”), to set foot in the campus of teachers and students, quiet and tastefully laid out and pleasant environment, visitors to civilization is a good addition to the urban environment [2]. Through investigation, analysis and practice, from the Angle of campus space characteristics, summarize the characteristics of plant landscape in colleges and universities, and puts forward the existing problems and the expected trend.
Index System of Ecological Planning of Urban Greenspace in Northeast China
Authors: Lin Yutang , Tang Yu
Published: March 2020

Nowadays, scientists generally apply routine index of greenspace system planning in urban greenspace planning and design. Along with its development, the ecological planning plays a more and more important role in urban planning of greenspace. This article attempts to establish a primary ecological index system of urban greenspace in northeast China by extracting some ecological index from the usual quantitative indicators, the ecological planning of greenspace heterogeneity, and diversity of the system and structure of urban greenspace system etc.
An Analysis Study of the Impact of Urbanization on Rainfall in Wuhan
Authors: Luo Tianyue , Liu Xuejun , Zhang Jiacheng , Wei Heyi
Published: March 2020

On the base of the hourly rainfall data of 102 weather stations of Wuhan in 2012, this paper calculates the area rainfall by using the Tyson polygon spatial interpolation method and applies the multiple linear regression model to analyze the impact of urban construction activities on the rainfall. It is concluded that from the perspective of the annual rainfall, rainfall and average temperature show a significant negative correlation, and this effect is also very significant in summer. This effect is also very significant in summer. At the same time, urban construction activities have a certain impact on rainfall in spring, summer, and autumn, which is reflected in the area of green area, water area and road density in the region. Among them, rainfall is most affected in summer.
Study on Climate Adaptation in Architectural Technology in Rural Areas
Authors: Wu Jingjing , Wei Hongyang
Published: March 2020

Climate adaptation in architectural technology, as a communication medium between nature and human beings, has become a new development trend in response to climate change and to encourage energy conservation and environmental protection. This paper aims to deal with the problems from the perspective of architectural technology in modern new rural construction. Based on the theory of climate adaptation, this paper expounds the definition of climate adaptation in architectural technology, and presents two operating mechanisms to guide and to defend. A suitable technical roadmap is thus offered for the development of architectural technology in rural areas, which can be summarized as the better design of fundamental schemes, preferential selection of passive architectural technology, reasonable implementation of low-energy active architectural technology, and efficient use of active architectural technology with high energy consumption, in order to provide reference for sustainable development of new rural construction. The results show that the response of architectural technology to climate change needs not only to focus on the material level, but also to pay attention to the activities of users.
Electronic structures and optoelectronic properties of ATiOPO4 (A = H, Li, Na, K, Rb, Cs, Fr, NH4, Ag) compounds and their applications in water splitting, CO2 reduction, and photo-degradation
Authors: Abdel-Sattar Mohamed K , Taha Mohamed
Published: March 2020

In this paper, we have presented a computational study on the crystal structures, electronic, and optical properties of the titanyl phosphate family (ATiOPO4, where A = H, Li, Na, K, Rb, Fr, NH4 and Ag). The lattice parameters and bandgaps were calculated with the Perdew-Burke-Ernzerhof (PBE), Revised Perdew-Burke-Ernzerhof (RPBE), Perdew Wang (PW91), Wu-Cohen (WC), and Perdew-Burke-Ernzerhof for solids (PBEsol) non-local functionals of the generalized gradient approximations (GAA). The PBEsol functional provided better results and closer to the experimental data of the ATiOPO4 compounds; and thus, this method was used to analyze the band structures, density of states, and optical properties. A comparison between the optical properties (dielectric function, refractive index, absorption coefficient, reflectivity, electron energy loss spectrum, and photoconductivity) of ATiOPO4 compounds were discussed. The potentials of valance band and conduction band edges were calculated and used to investigate the protentional applications of the ATiOPO4 materials in water splitting, CO2 reduction, and photo-degradation processes. The results obtained in our investigations show that many of the investigated ATiOPO4 semiconductors could be used as effective photocatalysts in these photocatalytic reactions.
Numerical modelling of the potential inside the cylindrical shaped nanocrystallite metal oxide semiconductors and its effect on gas sensor response
Authors: Kumar Anil , Kumar Ravi , Kumar Rakesh , B Prasad , Kumar Dinesh , Kumar Mukesh
Published: March 2020

The surface of metal oxide semiconductors exhibits great gas sensing response when the size of the grains becomes much smaller, i.e. in the range of the Debye length. In the presented work, the gas sensing properties of nanocrystalline cylindrical shaped metal oxide semiconductors have been studied. The effect of crystal size and surface states on gas sensor response has been investigated. The electric potential inside the grains has been calculated by solving the Poisson’s equation coupled with electroneutrality condition. The relationship between the electric potential and the size of the nanograins has been established as a function of available surface states, surface temperature and occupied surface states. It has been found that the critical value of available surface state density increases with an increase in the size of nanograins. Total carrier concentration inside the grain volume has been simulated as a function of available surface state density and grain size. Eventually, the sensitivity of the gas sensor has been simulated and compared for different sizes of nanocrystals. From the simulated studies, it is clear that the smaller cylindrical-shaped nanostructured grains could result in better gas sensing performances. Presented model has universal application for all metal oxides (both n-type and p-type) based semiconductors and can be extended for both oxidising and reducing gases with essential modifications.
The Magnus expansion and post-Lie algebras
Authors: Curry Charles , Ebrahimi-Fard Kurusch , Owren Brynjulf
Published: March 2020

We relate the classical and post-Lie Magnus expansions. Intertwining algebraic and geometric arguments allows us to place the classical Magnus expansion in the context of Lie group integrators.
Explicit Coleman integration for curves
Authors: Balakrishnan Jennifer , Tuitman Jan
Published: March 2020

The Coleman integral is a

p
p

-adic line integral that plays a key role in computing several important invariants in arithmetic geometry. We give an algorithm for explicit Coleman integration on curves, using the algorithms of the second author [Math. Comp. 85 (2016), pp. 961–981] and [Finite Fields Appl. 45 (2019), pp. 301–322] to compute the action of Frobenius on

p
p

-adic cohomology. We present a collection of examples computed with our implementation. This includes integrals on a genus 55 curve, where other methods do not currently seem practical.
Direction distribution for nodal components of random band-limited functions on surfaces
Authors: Eswarathasan Suresh , Wigman Igor
Published: March 2020

Let

(

M

,
g
)

(\mathcal {M},g)

be a smooth compact Riemannian surface with no boundary. Given a smooth vector field

V
V

with finitely many zeros on

M

\mathcal {M}

, we study the distribution of the number of tangencies to

V
V

of the nodal components of random band-limited functions. It is determined that in the high-energy limit, these obey a universal deterministic law, independent of the surface

M

\mathcal {M}

and the vector field

V
V

, that is supported precisely on the even integers

2

Z

>
0

2 \mathbb {Z}_{> 0}

.