bluuebunny/crossref_metadata_2025 huggingface dataset:
Model Design and Calculation Analysis of Large Span Space Structure
Authors: Yulin Peng , Jiali Yu , Yang Li
Published: September 2019

In order to work out the problem of insufficient bearing capacity for large span space structure, the structural model optimization design and fabrication process were researched by using Structure Analysis Program 2000(SAP2000) and Finite Element Analysis Software (ANSYS). The model strength, rigidity deformation and stability analysis were calculated respectively according to the software. A series of innovative work during the design and manufacture process of the entire model were carried out, finally by designing and making large-span spatial structure model and loading test, the loading characteristics of large-span spatial structure were gotten, and some design advice were put forward.
Study on Bolt Support Design for Carbonaceous Shale Tunnel of Highway at High Altitude and Cold Region
Authors: Guo Hongyan , Li Ke , Liu Xinrong , Cui Xiangyang , Luo Hao
Published: September 2019

With the large-scale development of road traffic infrastructure, tunnel construction gradually extends to high-altitude areas such as the Qinghai-Tibet Plateau. Under the influence of environmental and climatic conditions and regional geological tectonic movement, tunnel construction in this area cannot copy the technology and experience of low-altitude areas, and special research work should be carried out in accordance with regional geological characteristics. Based on a tunnel of Gongyu Highway, the bolt support design of high-altitude tunnel is studied by numerical analysis with FLAC3D software. The results show that the arch bolt should be cancelled and the side wall and lock foot bolt should be strengthened in the bolt support of highway tunnel in high-altitude cold area. Then through multi-dimensional comparative analysis, the length, circumferential spacing and setting range of anchor rods in the carbonaceous shale highway tunnel system at high altitude and cold region, as well as the number, direction and length of anchor rods at lock feet are put forward, which provides technical support for the design and construction of the relying projects, and also provides reference for similar projects.
Sensitivity Analysis of Dynamic Characteristics of Steel Plate Composite Girder Bridge with Supported Cross Beam System
Authors: Dou Weiyu
Published: September 2019

A steel plate composite girder bridge with support beam system was selected in the case study and the software of SAP2000 was adopted to build its refined seismic finite element model. A sensitivity analysis about the dynamic characteristics of the bridge was carried out and the design parameters included relative stiffness ratio of beam to slab, shear stiffness of shear nails and steel beam. The results show that: the stiffness ratio of beam to plate has little influence on the low-order modes of structure, but more significant influence on the high-order modes. Furthermore, in the high order modes, the effect of the stiffness of concrete slabs on the dynamic characteristics of high order modes of structures is greater than that of the stiffness of steel girders. Large reduction of the stiffness of shear nails significantly affects the natural vibration period, the order of mode shapes and the mass participation coefficient. Its influence on the vertical dynamic characteristics of bridge is significantly greater than the dynamic characteristics in the longitudinal direction and the in the horizontal direction. Steel beams have little influence on the dynamic characteristics of structures.
Research on the Stress Variation Effect of Overburden Loads in Utility Tunnel Roof
Authors: Yao Wen , Ma Jianxun , Xu Xin
Published: September 2019

As an underground structure, the utility tunnel is subjected to the pressure of overburden soil. Calculation of the overburden pressure soil are different when the burial depth changes. In this paper, the calculation methods of soil loads are summarized. In view of utility tunnel, the ANSYS finite element analysis is adopted to analyze the pressure of the roof. When calculating the structural stress, the working condition is considered as the backfill after the excavation of the soil. Considering the stress variation of the roof edge of the structure with different burial depth, it can be found that compressive stress at 1/2 span is about 1.7-2.2 times of the tensile stress at the corner. With the increase of burial depth, the rate of increasing roof stress value decreases. When the burial depth reaches a certain depth, soil arching effect plays a role and the roof stress value tends to be stable. Some suggestions are given to the designers of the utility tunnel which can reduce the waste of building materials.
Numerical Researches on the Optimization of Construction Methods in Tunnels with Super Large Section
Authors: Xiaosong Tang , Yongfu Wang , Yanyan Li
Published: September 2019

At present, the selection of construction methods in the tunnels with super large sections often relies on the experience for lack of a definite and feasible method. Based on the design method of formation-structure tunnels, the paper adopts FEM strength reduction to conduct numerical researches on the optimization of construction methods in tunnels with super large section. Taking a tunnel with super large section in a subway station as example, the paper first carries out numerical simulation on arch-wall method and double sidewall pilot tunnel method. Then it compares and analyzes the calculation results of surrounding rock displacement, stress on anchors and surrounding rock stability during construction. Finally, the paper suggests double sidewall pilot tunnel method. The analysis on the calculation examples shows that numerical method can quantitatively and directly display the difference between various construction methods and realize the optimization of construction methods in tunnels with super large section.
Analysis of Causes of Valve Rod Fracture of Steam Turbine High Pressure Main Steam Valve
Authors: Zhan Tu , Fuhai Lin , zhouquan zhang
Published: September 2019

A 300MW sub-critical coal-fired thermal power plant steam turbine generator set # 1 high pressure steam valve stem is fractured. The turbine unit has been running 46000 hours before the crack happened. The chemical component was examined which was in the standard range. they observed the metallographic structure of the broken stem to find the nitriding treatment of fine grain martensite structure at surface area and lath martensite at central section, healthy structure condition. they also found the existing of circumferential oxidized cracks with white corrosion production. According to that, they believe it was caused by residual stress when grinding. Finally, SEM was used to observe the fracture to further confirm our ideas.
Research on Testing Methods of Inspection of Buckling-Restrained Braces
Authors: Chen Wulong , Lou Guobiao
Published: September 2019

Testing methods of inspection of buckling-restrained braces is specified in many technical specifications, but the existing specifications do not clearly indicate the connection type used for the specimen. There are three main connection types of buckling-restrained braces applied in engineering. This paper has carried out a large number of tests, focusing on the influence of different connection types on the test results. For the welded joints specimen, typical test results of mechanical properties of buckling-restrained braces were obtained. For the bolted joints specimen, slippage is likely to occur during the test; for the pin joints specimen, misalignment is likely to occur during the test and they are not suitable for use. In order to ensure the normal operation of the test and the comparison of the test results, it is not necessary to simulate the connection types when the test of buckling-restrained braces is performed. No matter which connection type of the buckling-restrained braces is used in engineering, the unified connection type is recommended in the test. It is recommended to use the welded joints.
Research and Application of Xin’anjiang Model Parameters Uncertainty Based on GLUE Algorithm
Authors: Chen Ce , Ge Shilei , Liu Lijun , Wu Yi
Published: September 2019

Uncertainty study of hydrological model is an important subject in hydrological science research. Uncertainty analysis of model parameters is one of the important contents of hydrological model uncertainty research. This paper takes Hongjiata watershed as the research object, uses GLUE algorithm to analyze the uncertainty of parameters of Xin’anjiang model, and determines the sensitivity and range of parameters through the distribution law of qualified parameters. The conclusion shows that the GLUE algorithm can improve the calibration efficiency of Xin’anjiang model parameters and narrow the range of values, which can provide reference for model application in other areas.
Summary of Study on Toppling Deformation of Rock Slope
Authors: Xie Xiao , Li Qi , Guowei Zhang
Published: September 2019

The toppling of anti-dip layered rock slope is a typical mode of rock slope failure. Because this kind of deformation phenomenon is very common in hydraulic engineering and highway engineering, it has been paid more and more attention by the engineering community. The deformation mode, factors affecting toppling rock slope and dumping deformation mechanism were described in this paper.
Study on Slip Effects of Simply-supported Composite Beams
Authors: Chen Xu , Zhou Weixia , Kong Luzhi
Published: September 2019

The condition of the rigid shear connector of composite beams hardly exists in practice and interface slip is common due to the elastic shear connector. However, the rigid connector is often assumed in the design. What relationships for slip-induced effects? Is it small enough to be neglected? The classical differential equation is used to calcultae slip effects exactly. Results show that the slip-induced deflection is above 20% and the risk of crack must be considered for the bottom of concrete slab in midspan.
Mathematic Solution of the Differential Equations on Composite Beam Creep
Authors: Peng Zuqiang , Chen Xu , Zhang Shengping
Published: September 2019

The mathematic manual drivation is conducted to solve the classical creep and shrinkage system of differential equations of composite beams. By the differential multipier, the differential system is similar to the algberic system and can be solved analytically. The analytical formulars of the reditributed internal forces are obtained and they are useful for further research although it is complicate. The results of deduced formulars have been compared with those obtained by computer software.
Aerodynamic Load Analysis of Parts of Pantograph under Strong CrossWind
Authors: Zhao Meng , Liu Meiying , Liu Xiaoyu , Jia Yan
Published: September 2019

The pantograph-contact net model is established, and based on the N-S equation of the pressure correction procedure, the SIMPLE algorithm is used to solve the aerodynamic characteristics of different components of the pantograph under strong crosswind conditions. The effects of different crosswind speeds and different deflection angles on the aerodynamic load law of the pantograph components are discussed. Results show that among the various components of the pantograph, the aerodynamic drag and lift of the skateboard are the largest, and the lateral force of the lower arm and the bottom frame is also the largest. The pitching moment of the upper frame is the largest, and the overturning moment and the lateral moment of the sliding plate, the lower arm and the underframe are larger than before, which needs to be taken into consideration when we do calculations and optimizations. The research results can provide a basis for the operational safety and optimal design of high-speed pantograph under strong crosswind conditions.
Research and implementation of FOD detector for airport runway
Authors: Zhongda Yuan , Mingguang Liu , Xiuquan Cheng
Published: September 2019

A foreign object on an airport runway is also called a foreign object, that is, some foreign material, debris or object that may cause damage to the aircraft, such as scattered aircraft parts, luggage parts, wildlife, etc. On airport runway, there are mainly the activities of aircraft, less activities of human. As a result, most of the foreign objects on runway are parts that fall off the aircraft, mostly made of metal. Due to the strong suction of aircraft engines and high speed crushing of tires during take-off and landing, aircraft is relatively fragile compared with foreign bodies, and the presence of foreign bodies on the runway can cause serious damage to the structure of aircraft. A tiny object sucked into the engine could cause damage to the blades, and debris could accumulate in the machinery, affecting the plane’s normal operation. In view of the above problems, the research and realization of the FOD detector of airport runway are carried out in depth.
Assessing Public Satisfaction of Freeway Closure Measures in Fog and Haze Weather: A Questionnaire-Based Study in Hubei Province, China
Authors: Tan Jinhua , Qin Xuqian , Gong Li
Published: September 2019

In the current work, freeway closure measures in fog and haze weather are studied from the perspective of public satisfaction, in order to improve traffic management in Hubei province, China. Through an Internet survey to collect data, a structural equation model of public satisfaction of freeway closure measures in fog and haze weather is developed with public expectations, perceived quality, perceived value, public satisfaction, public complaints, support and understanding as variables. The results show that public’s supporting degree is not very high on the freeway closure measures. However, freeway intermittent release measures are the acceptable measures in fog and haze weather, which not only ensure traffic safety but also reduce economic losses and guarantee sustainable operation of freeway. Even though freeway closure measures are frequently taken due to serious fog and haze weather, intermittent release measures should also be taken into consideration so as to enhance public satisfaction and strengthen adaptive capacity of freeway to adverse weather.
Pile Active Underpinning of Existing Building Foundation with Undercrossing Shield Construction
Authors: Ma Hailong , Zhang Lixin , Ma Yufei , Yang Bilian , Yao Wenhong
Published: September 2019

Undercrossing shield construction of a subway, the tunnel vault is about 3.0m away from the foundation pile tip of the existing building. In order to analyze the influence of shield undercrossing construction on the existing building and the influence of the existing building load on the tunnel structure, the calculation and analysis are carried out for the existing foundation forms, foundation reinforcement into raft, addition of equal length piles and increase of unequal length piles. Using the method of foundation reinforcement into raft foundation and long pile tip exceeding 0.5m below the tunnel floor can transmit the load of the upper building structure to the soil layer below the tunnel floor and reduce the load of the tunnel roof, thereby achieving the underpinning effect. According to the allowable deformation value of existing building, allowable internal force of segment and allowable deformation value of segment, using this underpinning method can meet the requirements of the various of allowable values of existing building, tunnels, etc.
Finite Element Analysis of Bearing Capacity on the Composite Foundation of Group Pile
Authors: Teng Quan , Yao Xianhua , Li Shuguang , Guan Junfeng
Published: September 2019

In order to study the bearing characteristics on the composite foundation of group pile, the influences of variation of pile length, elastic modulus, spacing and cushion thickness on the bearing capacity for the composite foundation of group pile were investigated by finite element method. This paper presented the laws of the displacement and additional stress of pile with different parameters. The results showed that pile length, elastic modulus and spacing had great influence on the composite foundation of group pile; however, cushion thickness had less effective. Finally, this paper gave the optimal parameters, which provide a reference for practical engineering applications.
PFC model parameter calibration using uniform experimental design and a deep learning network
Authors: Zhai Shijie , Zhan Jiewei , Ba Yiding , Chen Jianping , Li Yuchao , Li Zhihai
Published: September 2019

A macroscopic parameter calibration method for the particle flow code (PFC) using a uniform experimental design and deep learning network is proposed to explore the relationship between the micro parameters and macro response of rocks. First, a sensitivity analysis was used to identify which micro parameters influence the macro factors. A uniform experimental design was applied to achieve this goal in this study. Then, a neural network based on batch normalization was constructed. Through a large number of numerical simulation tests, the relationship between the input (micro parameters) and output (macro response) can be obtained by deep neural network (DNN). Finally, the DNN model was used to perform validation by using marble in Jinping. The average error for the best results was only 4.211%. The main advantage of this method is that it can achieve fast parameter calibration compared with traditional calibration methods, and the calibration results can be obtained in only a few seconds through the designed program.
Field Test and Inspection of Large Area Hydraulic Sand Ground Improved by Vibro-compaction
Authors: De-yong Wang , Sheng Chen , Xiao-cong Liang
Published: September 2019

Liquefied Natural Gas (LNG) storage tanks have high requirements for the bearing capacity, settlement, resistance to liquefaction, and compactness of foundation. An LNG site about 500,000 m2 in the Middle East was hydraulic filled by trailing suction hopper dredger and cutter suction dredger, and it was improved by vibro-compaction. A filed test was carried out to optimize the key process parameters and inspection scheme. Field inspection methods included standard penetration test (SPT), cone penetration test (CPT), and zone load test (ZLT). The test results showed that the comprehensive inspection could be effectively inspected by CPT and SPT, the deformation modulus were back-calculated by ZLT and therefore the long-term settlement could be accurately predicted. The research can provide reference for the design, inspection and optimization of large area ground improved by vibro-compaction.
Research of the transfer relationship of the plastic region of the curved bridge based on the auxiliary system method
Authors: Yang Fan , Feng Tao , Wang Yanan , Jiao Xiwang , Xie Yan
Published: September 2019

Based on the member bars of one end fixed and one end free, it is a new method to study the relationship between the two ends of the curved beam by using the principle of virtual work and the balance equation. By analyzing the plastic hinge and the plastic region model of the curved beam, the transfer relation of the plastic hinge and the plastic region model is deduced by using the transfer matrix method of auxiliary system. Compared with the traditional initial parameter method, the transfer matrix method is more accurate and the calculation program is simpler. The results show that the transfer matrix method is correct and effective, and it can simulate the failure process of elastoplastic better and can be used for the initial design and final check-up of the curved bridge structures.
Application of Digital Optimum Design Technology in Mining Design of A Large Gold Mine in Ethiopia
Authors: Hong-gang Ren , Zheng Wei
Published: September 2019

In the decision-making process of mine project research, mining mode, mining method and production scale are the three core contents, which determine the investment and economic benefits of mine project. Based on the study of mining conditions, this paper establishes a digital three-dimensional geological model. By means of qualitative analysis, software optimization, man-machine interaction and multi-scheme comparison, the open-pit mining mode and mining boundary are determined, and the mining production scale is optimized. These methods take into account the influence factors of technology, economy and security, and provide reliable basis and technical guidance for project decision analysis.
Influence of suction chamber profile on flow field of annular jet pump
Authors: Wang X D , Chen Y L , Zhao Y , Xu Y , Wang B
Published: September 2019

Jet pump is a kind of fluid machinery, which uses jet shear and turbulent diffusion to transfer mass and energy. It is widely used in water project, civil engineering and other fields. In order to investigate the influence of suction chamber profile on flow field of annular jet pump, the conical suction chamber and the streamlined suction chamber were compared by applying turbulence numerical simulation method. The performance, pressure characteristics, velocity and turbulent energy distributions of annular jet pumps with two suction chambers are analysed. The calculation shows that compared with the traditional conical suction chamber, the efficiency of annular jet pump with streamlined suction chamber is improved at low flow ratio, and the change is not obvious at high flow ratio. In the same section, the cross sectional area of streamlined suction chamber is slightly larger than that of conical suction chamber, so the primary flow velocity near the wall is slightly lower, which can reduce the friction loss caused by high speed wall-attached flow. In addition, the smooth turning of the primary flow in streamlined suction chamber can weaken the extrusion on the entrained flow field. Different from the conical suction chamber, the streamlined suction chamber is smoothly connected with throat without sudden corner change, which can eliminate the low pressure near the inlet wall of throat, improve the wall pressure distribution and reduce the possible cavitation. The research results of suction chamber profile of annular jet pump can provide scientific basis for the popularization and application of jet pump.
A Multi-Objective Optimization Algorithm for Truss Structures
Authors: Jing Li , Zhuo-qun Zhang
Published: September 2019

For the optimization of multi-objective discrete variable structure optimization in civil engineering, a new improved multi-objective ant colony optimization algorithm for truss structures has been proposed in this paper. The new improved algorithm established two sets, including sets of feasible solutions and non-feasible solutions, and “the repeated solutions” was replaced with “the special solutions” to acquire the Pareto optimal front-end of the multi-objective problems. This algorithm can not only make the multi-objective ant colony algorithm better solve multi-objective problems under discrete variables, but also realize the successful application of multi-objective ant colony algorithm in truss structure. The present paper proposes a new improved multi-objective ant colony optimization algorithm for truss structures, which can provide a good performance in program design, arithmetic speed and generality of the proposed method. It is also a simple and practical, and suitable for projects in the future.
Railway route selection based on entropy weight method-gray correlation improvement TOPSIS
Authors: Zhou Ying , Liu Xixiao , Li Feng , Jiang Wen
Published: September 2019

In order to reasonably select the best railway route design scheme, the paper research the comprehensive evaluation model of TOPSIS based on entropy weight method-gray correlation. The paper establish the comprehensive evaluation index system from four aspects: technology, economy, society and environment. Then set up railway route selection model of gray correlation improvement TOPSISI, and use entropy weight method to determine the weight coefficient of each index. Finally, take the rail connection project as the example for verification. Making comparison of three alternative route design by using this model, respectively obtain the three scheme relative proximity are 0.575/0.543/0.551. The relative proximity of scheme 1 is the largest (0.575), which is the optimal design scheme, and it is consisted with the actual connection scheme. The paper use this model for railway route selection can make full use of objective data information and reduce the influence of subjective factors.
Application of Fuzzy Analytic Hierarchy Process in The Optimization of Railway Schemes
Authors: Yin Zihan , pu linqing , Luo Ruchang , Zhou Ying
Published: September 2019

The rapid development of economy is inseparable from the continuous construction of railways. Railway selection as the most important link in project construction must meet the requirements of national politics, economy and national defense. In this paper, the fuzzy analytic hierarchy process is used to take The Xuyong-Bijie Railway as an example to establish an evaluation system and calculate the evaluation grades of each index. The application of this method in the optimization of railway scheme can provide reference for actual route decision, and also verify the applicability and superiority of fuzzy analytic hierarchy process in railway line selection.
Exploration of Weihe River Fault at the Site of Weihe Bridge on National Highway 310 Xi’an Transit Highway
Authors: Lin Zhuo , Shu Youliang , Bian Jumei , Li Chunfeng
Published: September 2019

In this paper, the Weihe fault on the site of Weihe Bridge on State Highway 310 Xi’an Transit Highway is explored by combining high-density resistivity method with borehole geological section. The specific location of Weihe fault on the site of Weihe Bridge is determined, which provides a basis for seismic fortification and potential seismic source zoning of Weihe Bridge on State Highway 310 Xi’an Transit Highway.
Research on key technology of construction of long span continuous beam of high speed railway
Authors: Zhang Zhe , Yang Qijian
Published: September 2019

After entering the new era, China’s railway transportation industry has developed rapidly, and many high-speed railway projects have been emerging. Compared with ordinary railways, the trains on the high-speed railway have higher running speed, which need higher requirements on the rigidity of the bridge. In response to this situation, long-span continuous beam construction techniques are widely used in high-speed railway projects. Based on engineering cases, this paper analyzes the key technology for high-speed railway long-span continuous beam construction.
Deformation Characteristics of Deep Excavation for an Interchange Station Based on the Model of Hardening Soil
Authors: Wang Xiang-qiu , ZHEN Tu-yong , Liao Zhen-yuan
Published: September 2019

The interchange station of Foshan Metro Line 1 and Line 3 was regarded as the research object, and a three-dimensional finite element model was conducted by the software of Midas GTS to simulate the excavation of the metro station based on the constitutive model of hardening soil. The FEM results show that the diaphragm wall presents two deformation forms those are the kicking at the bottom of the wall and rigid translation into the pit. Comparing the numerical calculation and monitoring results of horizontal displacement of representative monitoring points of diaphragm wall under different excavation conditions, it is proved that the numerical results which based on the model of hardening soil is practicable in Pearl River Delta.
Review of study on post-earthquake stability of soil slopes
Authors: Chen Jinchang , Wang Lanmin , Pu Xiaowu
Published: September 2019

Under the action of earthquake, the slope will be damaged to varying degrees and the stability will be decreased. The stability of these slopes will be further reduced under the action of succedent rainfall and strong aftershocks, which will evolve into landslides. In addition, the damaged slope, even without the influence of external factors, may slip in a period of time after the earthquake, called progressive landslide or delayed landslide. The losses and casualties caused by the above landslides are often more serious than the coseismic landslides. This paper summarized the research results of post-earthquake stability of soil slopes at domestic and abroad. From the aspects of the damage characteristics, the evolve process of instability and the stability evaluation methods of soil slope, three types of landslides which are progressive landslide, post-rainfall and strong aftershocks induced landslide are analysed. The problems existing in the research and the direction of future research are also been discussed, which can provide some reference for related research work.
Seismic input model of high slope and its test verification
Authors: Zhang Boyan , Li Deyu , Li Chunlei
Published: September 2019

The Seismic input model of high slope is proposed, in which the Lagrangian discontinuous deformation analysis (LDDA) is adopted to simulate faults, cracks and structural surfaces, and the viscoelastic boundary is used as the energy absorbing boundary to reflect the influence of infinite foundation radiation damping. Due to employing the wave analysis method, the propagation and amplification effect of seismic waves in the slope can also be included. In order to verify the rationality of this calculated model, a slope dynamic model test of a large earthquake simulation shaking table was also carried out. From the results of experiment and numerical calculation, it can be seen that the acceleration of seismic response and its amplification effect, the slope base frequency and the opening degree of the simulated faults are comparable. The calculation model presented in this paper provides a good tool for correctly evaluating the seismic stability of the high slope near dam.
Static and Dynamic Stability Analysis of the Gravity Anchorage Slope Using the Three Dimensional Finite Element Method
Authors: Dan Luzhao , Tian Ming , Du Wenjie , Du Yuxiang , Fu Xiaodong
Published: September 2019

Stability evaluation of the high and steep slope formed by foundation excavation of a gravity anchorage is a key problem in safe construction and operation of the suspension bridge. Taking the gravity anchorage slope of Taoyuan Jinsha River Suspension Bridge of Dayong Expressway in Yunnan Province as a case study, through the field investigation and geological borehole data, a three dimensional finite element model was established to evaluate the stability of the anchorage foundation slope under the excavation and earthquake actions. The reinforcement effect of the support system including the anti-slide piles, bolts, pre-stressed anchor cable and lattice beam was studied. Using the support system, the maximum displacement of the slope decreased by 41%, and development of the plastic zone of the slope was controlled during the earthquake. The research results are used in the construction and design of this project, and also can be used for reference by the similar projects.
Study on Stability Theoretical of Bank Slope under Coupled Conditions
Authors: Wang Chang hong
Published: September 2019

In view of the factors affecting the soil bank slope of inland waterway and its analysis characteristics, the method of stability analysis of soil bank slope in inland waterway are put forward in the paper. On the basis of that, the soil slope under the influence of water level change, rainfall and ship traveling wave are analyzed, and the stability of the ecological slope after planting is analyzed. In order to consider the soil slope with multi factors, the finite element method should be adopted in the analysis of the stability of the soil bank slope under the combined action of many factors.
Study on the Three Gorges reservoir flood control operation chart considering comprehensive utilization requirements
Authors: Liu Xinyuan , Qu Geng , Guo Xiaohu , Yue Hongyan
Published: September 2019

This paper constructs a multi-objective flood forecasting optimization operation model based on inflow forecasting information considering flood control, power generation, and navigation. The optimization-simulation-test algorithm and modified differential evolution for multi-objective optimization (DEMO) were used. Some non-dominated solutions were derived from optimization of the inflow data of 126 years (1882-2007) and test by 1000-year design floods. The solutions were distributed uniformly and the algorithm was efficient. The flood during August 2009 was also used to test the selected solution. The results show that the optimal schemes can generate extra hydropower energy, and save great flood water resources. The navigation days for all types of ships are also increased greatly. To maximize comprehensive utilization benefits on the premise of flood control safety, the traditional design flood routing method is well combined with the optimization method by reservoir operation chart for flood control based on inflow forecasting, which provides a new way for reservoir flood control operation by considering the comprehensive utilization benefits.
Research on optimal design of slope anti-seepage
Authors: Wang Zhenyu , Yang Lingqiang , Sun Naidong
Published: September 2019

In order to study the seepage problem of the slope, the seep/w module in geo-studio is used to analyze the sluice of the Tanzhuang reservoir dam in Liaocheng, and the finite element simulation analysis of the slope seepage under different working conditions is obtained. A series of physical quantities such as seepage velocity, seepage flow and saturation line under working conditions. At the same time, the influence of different anti-seepage materials on the seepage of the slope is analyzed. The best combination of anti-seepage effect and economic benefit is obtained. The analysis results show: (1) In terms of anti-seepage effect: Compared with no anti-seepage measures, horizontal anti-seepage can reduce the seepage velocity to 81% before, and the anti-seepage effect is ideal. The vertical anti-seepage effect in the joint action with horizontal anti-seepage is extremely significant, and the seepage velocity can be reduced to 78% before. (2) In terms of project cost: The price of the anti-seepage film is relatively low, but the laying area is large, which requires a lot of manpower and material resources. The pouring concrete anti-seepage wall has a higher cost and the construction is more complicated. For this project, laying an anti-seepage film is more economical. (3) Comprehensive view: In order to combine the anti-seepage effect with the economic benefit, the combined action of the anti-seepage membrane and the anti-seepage wall is the best choice, and joint anti-seepage can be carried out at important parts, and only horizontal anti-seepage can be performed at the secondary position. The results of this study can provide reference for the same type of project, reduce construction costs, and further improve the stability of the slope.
Research on transitional pavement structures based on foundation settlement in goafs
Authors: Guo J J , Yang Z Y , Cheng L , Li X Y , Chen K P
Published: September 2019

Based on actual engineering geological conditions, foundation settlements and the effects of goaf’s positions on the settlements were measured to study the effects of underlying goaf on the road construction. Four transitional pavement structures with various base course were designed in goaf-affected areas. Under the soil consolidation settlement and traffic loading, the mechanical response of transitional pavement structures was simulated and analyzed. The critical safety zone of the goaf was obtained along the depth and the horizontal directions, respectively. The results indicate that the transitional pavement structure containing graded gravel base exhibited the minimum uneven settlement and pavement inclination under the condition of soil consolidation settlement. under traffic loading, the minimum tensile stress existed at the bottom of graded gravel base compared with that of the other three transitional pavement structures. Therefore, the flexible pavement with graded gravel base course is proposed as the transition pavement the mined-out areas.
Study on hazard assessment of mountainous flood in riverside country- a case study in Xinshan, Hubei, China
Authors: Li Zhe , Cai Bin
Published: September 2019

Mountainous riverside countries have already become the weaknesses of flood disaster control infrastructure in China, so flood calculation based on hydraulics models plays a key role in urban flood monitoring, warning and prevention. In order to validate the availability of a proposed one-dimension hydraulics flood model, the paper selects Xinshan County, Hubei Province, China as a typical study area. Considering the river distribution system and flood source analysis in Xinshan County, its flood scale and calculation scheme are then proposed. On the basis of HEC-RAS software, the one-dimension hydraulics model is constructed, which is applied to calculating the river flood evolutions and diffusing embankment processes with the designed flood probability of 0.01, 0.02, 0.05, 0.10, and 0.20 respectively. The comprehensive flood process information (such as diffuse area, diffuse duration and water depth) is also retrieved, which is used to calculate flood hazard and map flood hazard distribution. Calculation results reveal that the main parts of Gufu River basically meet the flood prevention standard of 0.05 (probability) in Xinshan County, while the intersection of Gufu River and Wangjia River has lower flood prevention ability than its flood prevention standard, which are basically consistent with local reality and flood estimation. Moreover, this fact proves that the proposed one-dimension hydraulics flood model is effective.
Study on Anti-seepage Effect of Different Schemes for Upper Reservoir of a Pumped Storage Power Station
Authors: kai Zhang , liqun Xu
Published: September 2019

With the development of geomenbrane, geomenbrane has been adopted in more and more hydraulic engineering as anti-seepage arrangement. A three-dimensional finite element model was built to analyze two different anti-seepage schemes for upper reservoir of a pumped storage power station. Under the reinforced concrete face slab & geomembrane anti-seepage scheme or geomembrane anti-seepage scheme, the seepage field and the seepage discharge of the reservoir were calculated and analyzed under normal conditions and local damage of geomenbrane conditions. It is shown that the seepage characteristic was obviously influenced by the fractured zone around right abutment. Moreover, based on the calculation results, seepage discharge under normal working conditions and local damage of geomembrane was analyzed and it was found out that both schemes were able to satisfied requirements of the reservoir under different conditions. After comprehensive consideration, it is recommended that the reinforced concrete face slab & geomembrane anti-seepage scheme should be adopted as the anti-seepage scheme of the reservoir.
Experimental Study on Seismic Performance of Multiple Ecological Composite Wall
Authors: Hou Lina , Huang Wei , Li Xuehua
Published: September 2019

The multiple ecological composite wall is the main force-bearing component of ecological composite wall structure. Its construction and mechanical properties are quite different from those of standard composite wall. In this paper, the low cycle cyclic loading test of multiple ecological wall is carried out, and the failure mode and process of composite ecological wall are discussed. On this basis, the seismic performance such as bearing capacity, deformation, ductility and energy dissipation are analyzed respectively. The Experimental results show that the multiple ecological wall has better seismic performance than the standard wall.
Analysis of Seismic Fragility of Aqueduct Structure Based on Copula Function
Authors: Zhang Yina , Cheng Gege , Zhang Shuai , Zhang Jianwei , Huang Jinlin
Published: September 2019

Establishing the joint probability distribution function directly of the basic components in the aqueduct system is hard, because of the correlation of seismic demand among components in structural vulnerability analysis. This paper proposed a new method for analyzing the vulnerability of aqueduct structure. A two-dimensional Copula function is introduced to describe the related structures of component seismic demands and simplify the modeling process of joint distribution function. The results show that the failure probability calculated based on Copula function is between the upper and lower bounds of the first-order boundary method. The results help to simplify the modeling process of the aqueduct system vulnerability curve, and at the same time, providing a new way to study the correlation between seismic demand of aqueduct components.
Analysis and seismic behavior verifacation of Zipingpu concrete faced rock-fill dam during Wenchuan Earthquake
Authors: Zhao Mengdie , Han Liwei , Zhang Xianlei , Li Zongkun
Published: September 2019

Based on the seismic damage of the Zipingpu dam in Wenchuan earthquake, the stochastic finite fault method with dynamic corner frequency is used to reconstruct the ground motion input acceleration time history of the Zipingpu dam in Wenchuan earthquake, and the dam-base-water seismic response analysis model is established. After analyzing the causes of dam deformation and panel joint dislocation after the earthquake, this paper suggested the comprehensive anti-seismic measures to improve the panel stress. These measures have important theoretical and practical significance for preventing the slab damage caused by extreme earthquakes in the concrete faced rock-fill dam (CRFD).
Study on the Influence of Pore Water Pressure on the Stability of Slope
Authors: Feng Yan , Zhu Feng , Li Senlin , Wu Ye
Published: September 2019

The influence of pore water pressure on slope stability under water drop and seismic action is studied in this paper, taking an embankment as the research object. The temporal changes of seepage field are analyzed first, and then the stability of dam slope is investigated by coupling the stress field with the seepage field. During the process of water drop, the minimum safety factor of slope stability appears at the moment when it stops falling. The greater the falling speed is, the faster the pore water pressure dissipates, and the smaller the safety factor is. Seismic action stimulates the increase of excess pore pressure, and whether to consider the coupling effect of seismic load and pore pressure change will make the results of stability analysis quite different. The cumulative effect of pore pressure may be the crucial factor of the dynamic instability of two-phase media slopes.
Discussion on constitutive relation of concrete creep and shrinkage by numerical calculation
Authors: Han Chunxiu , Shuang Chao , Zhang Jiuchang
Published: September 2019

In order to establish accurate and effective mechanical models of concrete creep and shrinkage by numerical calculation, the problems of parametric finite element analysis by APDL with ANSYS software and constitutive relations of creep and shrinkage by the creep criterion in the software are discussed. The accuracy of calculating creep coefficient and shrinkage strain by theoretical calculation and numerical simulation is analysed with an example. The calculation results show that the results from the two kinds of methods are in good agreement. It can get very good results to simulate the constitutive relationship of concrete creep and shrinkage by the software, achieving the basic function of accurately describing the long-term deformation effects of concrete. This function is the first and most important step in accurately simulating the long-term effects of complex constructions.
Analysis of seismic damage process of high concrete dam-foundation system
Authors: Cheng Heng , Zhang Guoxin , Jiang Chenfang , Liao Jianxin , Zhou Qiujing
Published: September 2019

In the anti-seismic analysis of concrete high dams, only the damage cracking of the dam concrete is usually considered, and the nonlinear characteristics of the dam foundation rock during the earthquake are not considered. Taking the Koyna gravity dam in India and Shapai arch dam in China as examples, this paper adopts the nonlinear time-history analysis method and takes into account the comprehensive influence of the radiation damping of infinite foundation, the hydrodynamic interaction between dam and reservoir, the nonlinear dynamic contact between various joints in the dam body and foundation, and the damage of dam concrete and foundation rock mass in the damage evolution process, analyzes damage evolution process of dam body-foundation system under earthquake action and the influence of foundation rock mass damage on seismic failure mode of concrete dam-foundation system, and compares the numerical simulation results with the actual earthquake situation. The calculation results show that after considering the damage of the dam foundation rock mass, the rock mass of the dam heel firstly appears to be damaged under the action of the earthquake and gradually expands into the interior of the foundation. The dam heel and the foundation surface are not damaged. The numerical simulation results are more in line with the actual situation of earthquake.
Numerical Analysis of Pipeline Vibration Characteristics in Large Pumping Stations
Authors: Cundong Xu , Junjiao Tian , Dongmeng Zhou , Zhipeng Yao , Fengyou Gu , Peng Zhang
Published: September 2019

This paper focuses on the high frequency vibration of the pipeline structure during operation of the large cascade pumping station. In order to explore its causes and inherent vibration characteristics, this paper takes #1 pressure pipeline of No.7 pump of Gansu Province Jingdian Project as the research object. The principle of additional mass method is used to establish a simplified fluid-solid coupling simulation model, and then the model is used to carry out numerical simulation test on the pipeline under different unit opening and closing conditions. After analyzing the numerical results of the simulation, the vibration mode and displacement deformation law are discovered and compared with the DASP field monitoring results. The results show that: under four representative working conditions, the vibration deformation of the pressure pipeline mainly occurs in the elbow section and the connecting section of the large and small tubes; the amplitude of the vibration mode increases with the increase of the modal order; furthermore, the water outlet pipe that is not easily vibrated in the high-order mode is gradually vibrated and deformed; in addition, the numerical simulation results are in good agreement with the field test results. This research can provide reference for the optimization design of pipeline vibration isolation and vibration reduction, and also provide a theoretical basis for the subsequent research on pipeline structural damage diagnosis and its safe operation.
The deteriorated microstructure characteristics of fly ash doped cementitious materials by dissolution
Authors: Li Xiang , Liu Chunfeng , Lu Chao , Peng Ziling , Li Jiazheng , Xingdong LV
Published: September 2019

The microstructure differentia of fly ash doped cementitious materials between before and after dissolution was observed by XRD and MIP to analyze the microstructural deterioration characteristics of different samples. Results showed that there were great changes in hydration products, cement clinker and fly ash particles after dissolution. Pore structure evolution during dissolution indicated that the effect of C-S-H decalcification on pore structure was not negligible and the traditional definition between the harmful pore and the harmless pore was not applicable.