Journal of Hebei University of Water Resources and Electric Engineering

Study on Dynamic and Static Mechanics and Fatigue Life of Flexible Pavement Structure

WANG Lei, WANG Zi-kun, SONG Yang, XIN Yuan-yuan, ZHANG Xue-qiang, YU Nan

2023, 33(2): 1-6. DOI: 10.16046/j.cnki.issn2096-5680.2023.02.001

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In order to study the stress response and fatigue life of flexible base asphalt pavement structure, based on the elastic layered system theory, bisar3. 0 calculation software calculates the mechanical response of typical pavement structure, summarizes the calculation data by adjusting the modulus of each structural layer, and analyzes the influence of dynamic and static mechanics on pavement design indexes. The results show that the change of dynamic and static mechanics is an important factor affecting the flexible pavement. With the increase of vehicle wheel set and modulus, the number of axle load actions of the design index decreases, and the fatigue life of the pavement decreases gradually. Therefore, the influence of dynamic and static mechanical changes should be fully considered in road design and construction, so as to lay a foundation for the implementation of flexible pavement in China.

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Application Study on Integrated Geophysical Prospecting to Dam Foundation Survey in a Certain Reservoir

LIU Wen-bo, LIU Sheng, LIU Kang-he

2023, 33(2): 7-11. DOI: 10.16046/j.cnki.issn2096-5680.2023.02.002

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In order to meet the basic requirements of concrete gravity dam for foundation rock(it needs to be built on hard bedrock), it is necessary to find out the thickness and change of overburden above the top surface of foundation rock in the dam site area, and explore whether there are geological defects in the foundation rock. This paper introduces the application of geophysical prospecting techniques such as high-density resistivity method, seismic imaging method and Rayleigh wave method in the survey of dam foundation of a certain reservoir in Shanxi. The variation law of the thickness of the Quaternary overburden is basically found out, the weathering grooves in the rock of the dam foundation are revealed, and detailed technical data are obtained, which provides a reliable scientific basis for the design of the reservoir project. The example proves that rational use of technical advantages of various geophysical methods can achieve the effect of complement each other and mutual verification, so as to improve the reliability and accuracy of geophysical test results and escort engineering construction and safety.

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Major Problems and Countermeasures in Dapo Tunnel Construction of Guizhou Zhangjiakou Changzhou Railway

FAN Zhen-long

2023, 33(2): 12-16. DOI: 10.16046/j.cnki.issn2096-5680.2023.02.003

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The Dapo Tunnel of the Qianzhang Changzhou Railway is a Level I high-risk tunnel, which is quite difficult to construct and has many major construction problems. Many research results of domestic and foreign scholars have been used for reference in the construction process.The engineering background and main geological conditions of the Dapo Tunnel are introduced. And the tunnel construction difficulties and corresponding countermeasures in fault fracture zones, water and mud inrush zones, various lithological contact zones, and shallow buried areas are summarized in the article, which can serve as a reference for the similar projects.

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Effect of Fine Particle Content on Mechanical Properties of Frozen Soil -pile Foundation Interface

MA Jiang-ping

2023, 33(2): 17-22. DOI: 10.16046/j.cnki.issn2096-5680.2023.02.004

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The shear characteristics of the frozen soil pile foundation interface have a significant impact on the stability and long-term service life of traffic engineering in frozen soil areas. This article studies the influence of fine particle content on the mechanical properties of the interface between frozen soil and concrete pile foundation through negative temperature direct shear tests.The research results show that the stress and displacement curve sample all show the stress softening model. The peak interfacial shear strength and ice bonding strength increase with the increase of fine grain content, and the residual strength has little fluctuation with the change of fine grain content. With the increase of fine particle content, the contribution of ice cementation strength to the interfacial shear strength of frozen soil and concrete gradually increases. The peak strength and residual strength of the samples increased linearly with the change of normal pressure, and the intensity of 50kPa to 100kPa increased sharply than that of other pressure intervals. The peak cohesion increases with the increase of fine particle content, and the residual cohesion decreases with the increase of fine particle content. The calculation formula of interface shear strength between frozen soil and concrete is established and its accuracy is verified.

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Support Design and Monitoring Technology of Deep Foundation Pit of adjacent Building

YANG Bin

2023, 33(2): 23-27. DOI: 10.16046/j.cnki.issn2096-5680.2023.02.005

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The deep foundation pit of Xining Street Subway Station of Shenyang Metro Line 1 has a depth of 18m and is close to the office building. Considering the soil layer and the elevation of the groundwater level in the foundation pit area, reinforced concrete retaining piles are selected as the main structure of the foundation pit support. In order to minimize the surface settlement around the foundation pit, scientific design of preload of steel purlin and internal support a detailed monitoring programme has also been developed. Engineering practice shows that the simulation calculation results of Lizheng software are highly consistent with the monitoring results in construction, which ensures the safety of the pit side buildings in the construction process, and also shows that the calculation results are accurate and reliable, which can provide reference for similar foundation pit support and monitoring.

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Study on Wind Resistance of Double Column Bridge Tower with Irregular Section

CHEN Zhen-hua, XIANG Huo-yue, GUO Yu-jia

2023, 33(2): 28-33. DOI: 10.16046/j.cnki.issn2096-5680.2023.02.006

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Based on the practical projects, the wind resistance of the bridge tower with irregular section is analyzed by CFD numerical simulation. The aerodynamic coefficients and Strouhal numbers of single column and double column at different wind angles and spacing ratios are calculated and studied. The variation of time-mean pressure and time-mean vortex streamlines in the flow field near the double column are analyzed. The results show that the drag coefficient and Strouhal number of two tower columns are reduced to different degrees compared with that of a single tower column. With the increase of wind angle, the drag coefficient of single tower column and upstream tower column decreases, while the drag coefficient of downstream tower column increases. Strouhal number is not sensitive to changes in wind angle and spacing ratio. With the increase of the spacing ratio, the resistance coefficient of the upstream column increases and gradually approaches that of a single column. When the spacing ratio is 4, the drag coefficient of the two towers changes greatly, and the Strouhal number is the smallest. In this case, the large vortex between the two towers breaks, and an independent small vortex appears near the two towers.

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Study on Service Life of Reinforced Concrete Structure Based on Reliability

CHEN Hao

2023, 33(2): 34-39. DOI: 10.16046/j.cnki.issn2096-5680.2023.02.007

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Based on main characteristics and failure mechanism of reinforced concrete structure under salt and freeze-thaw action, service life models of reinforced concrete structure are established, which is in the influence of relative dynamic elastic modulus of concrete, chloride ion concentration of reinforced, and denudation degree of concrete. Then, combining the reliability theory and loading capacity design of reinforced concrete structure, the life prediction model of reinforced concrete structure is established. Finally, an engineering case of urban overpass is used to verify the correctness and reliability of service life models, which shows that the durability design of reinforced concrete structures in current specifications is not safe and should be revised in the method of reliability theory.

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Experimental Study on Damping Ratio of Rock Samples Based on Transient Excitation

ZHENG Shi-duo, FAN Qing-shan, ZHANG Shu-qiang, LIU Tao, LIU Wei-ran

2023, 33(2): 40-46. DOI: 10.16046/j.cnki.issn2096-5680.2023.02.008

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The rock damping ratio is one of the important dynamic characteristic parameters in the foundation engineering design of industrial and civil buildings. In order to master the damping ratio of bedrock in the nuclear island area of a nuclear power plant unit, transient excitation is used to make the rock sample generate free vibration in combination with the actual situation of the project. Vibration signals by pasting strain gauges and acceleration sensors on the rock sample are collected, the damping ratio of the rock sample through calculation is obtained, and the damping measured by the two collected signals are compared. This study provides some reference for similar projects.

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Research Status of Application of Waste Circuit Board Powder in Building Materials

CHEN Yao-hua, LIU Jie-sheng, WEI Jing, ZHANG Yi-di, WANG Lei

2023, 33(2): 47-50. DOI: 10.16046/j.cnki.issn2096-5680.2023.02.009

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Waste circuit boards are hazardous wastes, and the accumulation is increasing. It is urgent to solve the pollution of waste circuit boards. The non-metal part of the waste circuit board is ground into powder (waste circuit board powder) and mixed with building materials, which can change its related performance. This article expounds the source of waste circuit boards in our country and the treatment and utilization of non-metallic parts of waste circuit boards, discusses the feasibility and safety of adding discarded circuit boards powder to cement-based materials, summarized the current status of its use in cement-based materials, asphalt, coatings and other construction materials, and summarized other recent utilization of waste circuit boards powder, provides a feasible solution for the disposal of discarded circuit boards powder and their application in building materials.

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Seismic Analysis and Research of Out-of-code High-rise Building D in a Library

LIU Zhong, LIU Huai-bin

2023, 33(2): 51-56. DOI: 10.16046/j.cnki.issn2096-5680.2023.02.010

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Reinforced concrete frame-shear wall structure system of building D of a library, the structure has irregular terms such as plane torsional irregularity, partial discontinuity of floor slab, discontinuity of components and other irregularity(local cross-layer columns), is an out-of-code high-rise structure. Combined with its characteristics, it is necessary to carry out structural seismic analysis and research. PMSAP and Midas Gen software were used to analyze the response spectrum of the structure under the action of multiple earthquakes, the calculation results of period,baseshear,maximum story drift ratio and floor displacement of the two software were very similar.PMSAP software was used to analyze the performance of structural components under earthquake protection, and the shear wall,frame column and frame beam all met the expected performance level of shear elasticity,bending resistance and non-yield.SAUSAGE software was used for dynamic elasto-plastic analysis of the structure under rare earthquake, ensure the seismic safety of the main structure. The research results show that the structure design meets the requirements of the code in combination with strengthening measures and special analysis.

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Cangzhou Section of the Grand Canal Ecosystem Service Function Assessment

WANG Ya-qin, GUO Shao-qi, DONG Xiao-li, LI Lu, WANG Feng-chun

2023, 33(2): 57-62. DOI: 10.16046/j.cnki.issn2096-5680.2023.02.011

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By evaluating the current situation of the ecological service function of the Cangzhou section of the Grand Canal, this paper studied the value of the ecological products provided by the Cangzhou section of the Grand Canal and their transformation ways, and established the evaluation system of the ecological service function of the Cangzhou section of the Grand Canal, including 12 indicators of 4 functions, such as including supply, regulation, culture and supporting. According to the classification method of the United Nations Millennium Ecosystem Assessment, the substitution engineering method, market value method, willingness to pay method and other methods were used to calculate the value status quo. The results showed that the value of the ecosystem services of the Cangzhou section of the Grand Canal would be 41.3862 billion yuan, providing theoretical support for promoting the sustainable development of the ecosystem and economy in Cangzhou city.

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Stability Analysis of Xiejia Dam under Scouring action of South Canal Based on GeoStudio

WEN Yong-fu, WANG Feng-chun, HAN Chao, ZHANG Jing-xiao, LI Jing-jing, WANG He

2023, 33(2): 63-69. DOI: 10.16046/j.cnki.issn2096-5680.2023.02.012

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In order to study the stability change rule of Xiejia Dam under river scouring and the influence of mortar mixed with glutinous rice on the stability of the beach-wall, the calculation theory of river bed scouring and beach-wall erosion retreat is combined to conduct numerical simulation analysis on different beach-wall materials and whether river scouring is considered or not. The results show that:(1)No matter the water level rises or falls, the transverse scour distance of the beach-wall is greater than the longitudinal scour distance of the river bed. (2)The beach-wall becomes higher and steeper due to scouring, which accelerates beach-wall destabilization. (3)The mortar mixed with glutinous rice can improve the stability of beach-wall, and its safety factor is 1.29~1.49 times higher than that of plain soil.

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Solving Layout Problem by Unilateral Lowest Horizontal Line Method on Guillotine Constraint

ZHANG Peng-cheng, WANG Wen-cheng, ZHANG Tie-bi, FENG Han-ping

2023, 33(2): 70-76. DOI: 10.16046/j.cnki.issn2096-5680.2023.02.013

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A single-sided lowest horizontal line method that satisfies the ‘one-size-fits-all’ constraint is proposed, Which is based on the existing lowest horizontal line method. When selecting the placement order and placement position of rectangular parts, the leftmost rectangle is used as the benchmark. All rectangles are layered and densely distributed, so that the layout combination not only meets the high material utilization rate, but also makes the rectangular placement meet the process requirements of ‘one-size-fits-all’, thereby shorten the tool processing stroke and improving the processing efficiency.

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Finite Element Analysis and Safety Evaluation of X80 Steel with Crack Defect

Wang Jing, Yang Bin, SHI Yan

2023, 33(2): 77-82. DOI: 10.16046/j.cnki.issn2096-5680.2023.02.014

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X80 steel is a low carbon alloy steel with controlled rolling and cooling. It has good strength and toughness and is widely used in oil and gas transportation pipelines. In recent years, failure accidents caused by welding cracks have occurred frequently, and the service safety of welded joints has attracted much attention. The safety evaluation of X80 steel welded joints with cracks is of great significance. In this paper, the fracture parameters of X80 steel welded joints under different stress states, different crack locations and different strength matching under the same load are calculated by finite element simulation. The results show that no matter whether the joint is in the plane stress or plane strain state, high matching or low matching, under the same load, when the crack is located in the heat affected zone (hereinafter referred to as “HAZ”) and the fusion line, the J-integral value is larger than that of the base metal and weld, and the J-integral value at the fusion line is the largest, and the joint is the most dangerous.

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