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Acoustic emission characteristics of damage evolution of multi-scale fiber reinforced rubberized concrete under uniaxial compression and tension after being subjected to high temperatures

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Frontiers of structural and Civil Engineering 2024年第8期18卷 1237-1266页

作者： Shaoqi ZHANG Yao ZHANG Qianru LEI Yumeng YANG Yichao WANG Fei XU Zhiguo YAN Hehua ZHU Laboratory of Fire Safety School of Safety Engineering and Emergency ManagementShijiazhuang Tiedao UniversityShijiazhuang 050043China Structural Health Monitoring and Control Key Laboratory of Hebei Province Shijiazhuang Tiedao UniversityShijiazhuang 050043China Department of Geotechnical Engineering Tongji UniversityShanghai 200092China

Recently developed multi-scale fiber(i.e.,CaCO3 whisker,polyvinyl alcohol(PVA)fiber,and steel fiber)reinforced rubberized concrete exhibits excellent mechanical properties and spalling resistance at high *** of macro properties such as strength and Young’s modulus cannot reveal and characterize damage mechanisms,particularly those relating to the multi-scale fiber strengthening *** this study,acoustic emission(AE)technology is applied to investigate the impact of multi-scale fiber on the damage evolution of rubberized concrete exposed to high temperatures,under the uniaxial compression and tension loading *** mechanical properties,AE event location,peak frequency,b-value,the ratio of rise time to amplitude(RA),average frequency(AF)values,and AE energy of specimens are *** results show that the number of events observed using AE gradually increases as the loading *** crumb rubber and fibers inhibit the generation and development of the *** is concluded that both the peak frequency and b-value reflect the extension process of *** the cracks develop from the micro scale to the macro scale,the peak frequency tends to be distributed in a lower frequency range,and the b-value decreases *** the peak stress point,the AE energy increases rapidly and the b-value *** specimens without multi-scale fibers exhibit brittle failure,while the specimens with fibers exhibit ductile *** addition,adding multi-scale fibers and crumb rubber increases the peak frequency in the medium and high frequency ranges,indicating a positive effect on inhibiting crack *** being subjected to high temperatures,the maximum and minimum b-values decrease,reflecting an increase in the number of initial cracks due to thermal ***,the RA and AF values are used to classify tensile and shear *** specimens fracture with more shear cracks under compression,and there are more tensile

关键词： multi-scale fibers acoustic emission fracture damage evolution rubberized concrete

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Compensation method and sensitivity analysis of DPHP frozen soil ice content measurement

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Research in Cold and Arid Regions 2025年第2期17卷 85-96页

作者： Cai, YongMing Wang, Meng Li, Xu Chen, WenHua Candidate Key Laboratory of Urban Underground Engineering of Ministry of Education Beijing Jiaotong University Beijing 100044 China Key Laboratory of Structural Health Monitoring and Control Shijiazhuang Tiedao University Hebei Shijiazhuang 050043 China School of Civil Engineering Beijing Jiaotong University Beijing 100044 China

The Duel-Probe-Heat-Pulse (DPHP) ice content sensor can measure the ice content of the soil, but its measurement process is not clear for the disturbance of frozen soil. In this study, the ice content measurement test was carried out for silty clay specimens. Firstly, the influence of heating power was clarified. The variation trends of the temperature rise relaxation area in the respective conditions of the three representative volumetric water content specimens and the degree of compaction of the specimen preparation was compared. Then, the influence of five kinds of heating interval time on the measurement accuracy was explored. Finally, the compensation and analysis method of the temperature relaxation area, based on the temperature of the measuring point and the phase change of ice water, is proposed. The experimental results show that: (1) There is a hysteresis in the temperature rise curve of the probe of the DPHP ice content sensor. In the measurement process, a long enough integral interval should be selected to calculate the temperature relaxation area. (2) For the specimens with the same initial water content, the measured temperature relaxation area increases with the increase of compaction degree, and this trend weakens in the specimens with the increase of water content. (3) The DPHP ice content sensor causes irreversible disturbance to the soil during the measurement process. The temperature relaxation area, obtained by continuous measurement at a short heating interval, is small, and manifests a decreasing trend with the increase of measurement times. (4) It is recommended that the heating interval time should be more than 120 min, and the temperature relaxation area should be compensated when the continuous measurement of short heating interval time is carried out, to offset the influence of the temperature rise of the measuring point. The research results reveals the influence of multiple factors on the measurement of DPHP ice content sensors, whic

关键词： Duel-probe-heat-pulse method Soil ice content Temperature modeling compensation Temperature relaxation area Thermal conductivity

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Full-Scale Cutting Experiments of Different Granite Integrity Using Tunnel Boring Machine Disc Cutter

SSRN

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SSRN 2022年

作者： Sun, Hao-Kai Gao, Yang Chen, Yong Geotechnical and Structural Engineering Research Center Shandong University Jinan250061 China Key Laboratory for Structure Health Monitoring and Control in Hebei Province Shijiazhuang Tiedao University Shijiazhuang050043 China

The complex geological conditions of tunnels with tunnel boring machine make geological exploration very difficult. To explore the method of predicting the rock mass integrity based on the cutterhead vibration signal, the mapping relationship between the rock mass integrity, cutter forces, and cutterhead vibration was studied by the full-scale rotary cutting machine. Our finding is that the mean amplitude, the single peak value of the normal force, and the RMS values of the cutterhead vibration all increase with ascending rock mass integrity. The average amplitude and single peak value decrease, and the RMS value increase with the increase of the rotation speed. The average amplitude increases, the single peak value decreases, and the RMS value increases as the advance speed increase. We demonstrated that there is an obvious corresponding relationship between the normal force and the vibration, and rock mass and operating parameters have significant effects on the vibration characteristics. © 2022, The Authors. All rights reserved.

关键词： Boring machines (machine tools)

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Hpp-Based Evaluation of 17 Thermal Conductivity Models for Frozen Soil

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SSRN 2023年

作者： Zheng, Shuang-Fei Wang, Meng Li, Xu Tai, Bo-Wen Li, Guo-Yu Key Laboratory of Urban Underground Engineering of Ministry of Education Beijing Jiaotong University Beijing100044 China Key Laboratory of Structural Health Monitoring and Control Shijiazhuang Tiedao University Hebei province Shijiazhuang050043 China State Key Laboratory of Frozen Soil Engineering Northwest Institute of Eco-Environment and Resources Chinese Academy Sciences Lanzhou730000 China

Thermal conductivity is a key parameter for coupled thermal-hydro-mechanical calculations, significantly influencing the determination of the water and heat migration in frozen soil. However, during the measurement of thermal conductivity for frozen soil, the accuracy can be affected by the interference of ice and water caused by phase transitions with temperature elevation. Consequently, the experimental data on thermal conductivity for frozen soil is insufficient. In this study, the heat-pulse-probe (HPP) method was adopted to conduct measurements of thermal conductivity in silty clay, sand and sand loam, with the temperature perturbation of less than 0.3°C. Additionally, nuclear magnetic resonance (NMR) experiments were implemented to measure the unfrozen water content, enabling further calculation of the ice content. Furthermore, a literature review was conducted to categorize 17 commonly used thermal conductivity calculation models as normalized and hybrid models. The models were evaluated using the λ-θi-θw experimental data, leading to the following conclusions: Among the seven hybrid models, Zhang model shows the best predictive performance and requires no undetermined parameters, making it easy to apply. Sass model is suitable for soils insensitive to deformation of the frozen volume, such as the sand and sand loam studied in this research. Tian model requires the determination of soil-specific parameters, and when the parameters are appropriate, it demonstrates good predictive performance, as observed for the silty clay. Among the 10 normalized models, Joh, Cot, and Luo models are the three with the smallest errors. The establishment of the Ke function needs to consider variations in ice content during phase transitions and changes in the air volume fraction caused by deformation of the frozen volume. These research findings can provide references for future studies on thermal conductivity. © 2023, The Authors. All rights reserved.

关键词： Thermal conductivity

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Damage evolution analysis of rock under Uniaxial compression and Brazilian splitting based on discrete element method 10

Damage evolution analysis of rock under Uniaxial compression...

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2020 10th Chinese Geosynthetics Conference and International Symposium on Civil Engineering and Geosynthetics, ISCEG 2020

作者： De-Kang, Li Hao-Ran, Li Meng, Liu Zi-Heng, Wang Zheng, Li Structural Health Monitoring and Control Institute Shijiazhuang Tiedao University Shijiazhuang Hebei050043 China Key Laboratory for Health Monitoring and Control of Large Structures Shijiazhuang Tiedao University Shijiazhuang Hebei050043 China Second Geological Team of Hebei Coalfield Geological Bureau Xingtai Hebei054001 China

In order to better analyze the mechanical behavior of rock in uniaxial compression and Brazilian splitting, numerical model was established according to laboratory test by PFC2D particle flow program, and the simulation results were compared with the experimental results. The results show that when the rock reaches the peak stress, the failure curve of cement appears an obvious turning point, and the failure rate of cement *** compressive strength of rock is much greater than the tensile strength under compression condition. The preloading method is more detailed for experimental restoration, and it provides certain reference significance for rock simulation in the future. © The Authors, published by EDP Sciences 2020.

关键词： Rocks

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A long-term vertical displacement prediction method of concrete bridges based on meteorological shared data and optimized GRU model

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Measurement: Journal of the International Measurement Confederation 2025年 253卷

作者： Wang, Xu Xie, Guilin Liu, Wentao Kong, Hu Gao, Yang State Key Laboratory of Mountain Bridge and Tunnel Engineering Chongqing Jiaotong University Chongqing400074 China School of Civil Engineering Chongqing Jiaotong University Chongqing400074 China China Merchants Chongqing Road Engineering Inspection Center Co. Ltd Chongqing400067 China Department of Civil and Transportation Engineering Hohai University Nanjing210098 China Key Laboratory for Structure Health Monitoring and Control in Hebei Province Shijiazhuang Tiedao University Shijiazhuang050043 China

Based on data from the meteorological shared data platform, this study proposes a method for predicting the long-term vertical displacement (VD) of concrete bridges by integrating the Northern Goshawk Optimization (NGO) algorithm with the Gated Recurrent Unit (GRU) network. This method can be employed to safely assess concrete bridges and recover missing VD data. Specifically, it uses historical meteorological information and time information provided by the meteorological shared data platform (European Centre for Medium-Range Weather Forecasts) to generate the input parameters of the GRU model. It then employs the long-term VD data from the concrete bridge structural health monitoring system to produce the output parameters of the GRU model. Moreover, the hyperparameters for the GRU model training are optimized using the NGO algorithm. Four NGO-GRU models with different input conditions are proposed, taking the long-term VD prediction of a prestressed concrete bridge as a case study and considering the correlation between different meteorological factors and VD and the long-term time-dependent effects on concrete structures. Through a comparative analysis of the model's prediction performance of multiple sensors under different conditions, it is found that the NGO-GRU model achieved the best prediction performance when using a combination of air temperature, time information, air pressure, solar radiation intensity, and wind speed as inputs, with a prediction error of less than 6.00%. Furthermore, compared with the benchmark models, the NGO-GRU model demonstrated the highest accuracy in VD prediction. Under the optimal input conditions, the prediction performance of the NGO-GRU model improved by 16.46% to 46.17% compared with the other models, validating the robustness and effectiveness of the proposed method. © 2025 Elsevier Ltd

关键词： Concrete bridges Long-term monitoring Meteorological shared data Northern goshawk optimization-based GRU structural health monitoring Vertical displacement

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Evolution Law of Frost-Heaving Pressure of Frozen Circles in Surrounding Rock around Water-Rich Tunnels in Cold Regions

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Zhongguo Gonglu Xuebao/China Journal of Highway and Transport 2022年第9期35卷 340-351页

作者： Zheng, Xin-Yu Xu, Fei Sun, Hao-Kai Gao, Yang Wei, Li-Yuan Geotechnical and Structural Engineering Research Center Shandong University Shandong Jinan250061 China Key Laboratory of Large Structure Health Monitoring and Control Shijiazhuang Tiedao University Hebei Shijiazhuang050043 China State Key Laboratory for Geomechanics & Deep Underground Engineering China University of Mining and Technology Jiangsu Xuzhou221116 China School of Civil Engineering Southwest Jiaotong University Sichuan Chengdu610031 China

The frost-heaving evolution mechanism of frozen circles in surrounding rock around water-rich tunnel is a key scientific problem that affects the operation safety in cold regions. To explore the evolution law of frost-heaving pressure in frozen circles in such surrounding rock, scaled three-dimensional geomechanical model tests were carried out. In these tests, freezing of a water-bearing surrounding rock at low temperature was considered. The temperature field distribution characteristics of surrounding rock at the tunnel portal section was simulated by introducing ambient air into the tunnel for cooling. Micro-pressure sensors were employed to dynamically monitor the frost-heaving pressure in real time. The spatial and temporal evolution curves of the frost-heaving pressure were obtained for various water content and thickness in surrounding rock. The fitting formulas for parameters such as the frost-heaving rate of surrounding rock, thickness of the frozen circles, and water content were established utilizing multiple regression analysis. Based on this, a theoretical solution for the frost-heaving pressure of the frozen circles in surrounding rock under plain strain state was derived considering the influence of water content and proportion index of surrounding rock. The thermal stress method was used to simulate the evolution characteristics of frost-heaving pressure. Combined with numerical simulations, the test method and theoretical solution were further verified by comparing the predicted frost-heaving pressure with the theoretical and test values. The results indicate that the temperature field of surrounding rock undergoes changes in three stages. This is similar to a regular spoon with a handle-like evolution process;the temperature field of the water-bearing surrounding rock exhibits a non-linear distribution in the descending stage;the temperature field of surrounding rock shows a lagging characteristic relative to the environmental temperature. The sha

关键词： Temperature

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Comprehensive Verification and Analysis of Multi-Scale Remote Sensing Products for Surface Freezing- Thawing Status on the Qinghai-Tibet Plateau

Comprehensive Verification and Analysis of Multi-Scale Remot...

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IEEE International Symposium on Geoscience and Remote Sensing (IGARSS)

作者： Xiaokang Kou Zhaoyang Jia Shuang Yan Mengjie Jin Yuzhi Zhang Tianliang Wang Key Laboratory of Roads and Railway Engineering Safety Control (Shijiazhuang Tiedao University) Ministry of Education Shijiazhuang Hebei China School of Civil Engineering Shijiazhuang Tiedao University Shijiazhuang Hebei China Institute of Geographical Sciences Hebei Academy of Sciences Hebei Engineering Research Center for Geographic Information Application Shijiazhuang Hebei China Key Laboratory for Health Monitoring and Control of Large Structures in Hebei Province Shijiazhuang Tiedao University Shijiazhuang Hebei China

ISBN: (数字)9781728163741

ISBN: (纸本)9781728163758

The surface soil freezing and thawing (F/T) status plays important roles in water and energy exchanges, hydrology cycle and terrestrial ecosystem. Passive microwave remote sensing tends to be one of the most effective ways of monitoring global surface F/T status, due to its strong sensitivity to the changes of liquid water and its short revisiting period. Many surface F/T products have been produced based on the observations from different passive microwave sensors. However, due to the differences in spatial scales, satellite data sources, transit times etc., the accuracy and the consistency of different F/T products need to be well considered in front of the comprehensive utilization. In this study, the surface F/T products with resolutions of 36 km, 25 km, 25 km and 6 km derived from SMAP, SSMIS, AMSR-2, AMSR-2 (downscaling) were validated separately based on the in-situ observations in Ngari prefecture and Maqu on the Qinghai-Tibet Plateau. Then a comparison analysis was conducted on the F/T products derived from SMAP and SSMIS to figure out the consistency between F/T products derived from different sensors. The results show that: 1) the verification accuracy in Maqu is higher than that in Ngari prefecture, which reflects the limited capability of passive microwave in identifying the soil surface F/T status in the arid region. 2) The F/T products with resolutions of 6 km and 25 km, which were both derived from AMSR-2 and have the same transit time, showed similar validation accuracies. 3) There is a good agreement between the F/T products derived from SMAP and that from SSMIS. This study will be conducive to the comprehensive application of multi-scale F/T products in the fields of climate change and ecological environment.

关键词： Microwave radiometry Microwave theory and techniques Satellite broadcasting Land surface Spatial resolution Microwave imaging Orbits

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Main Structure Design and Constructional Safety control of Large-span Gravel Surrounding-Rock Tunnel

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IOP Conference Series: Materials Science and Engineering 2020年第6期780卷

作者： Li De-kang Li Hao-ran OuYang Zuo-lin Yue Zhi-guo Dong Yan-dong Structural Health Monitoring and Control Institute Shijiazhuang Tiedao University Shijiazhuang Hebei 050043 China The Key Laboratory for Health Monitoring and Control of Large Structures Shijiazhuang Tiedao University Shijiazhuang Hebei 050043 China Shuohuang Railway Development Limited Liability Company Yuanping Shanxi 034100 China

As the construction of large-span gravel surrounding-rock tunnel is very difficult which has serious security risks, it is significant to choose a set of reasonable structure design methods and safety control schemes. This paper taked a large-span gravel road tunnel in Jinan Expressway as an example. Through combining theoretical analysis with numerical simulation, the main structure design process of the large-span IV level surrounding-rock tunnel was divided into four steps, meanwhile concrete measure basis and testing methods were given. According to the engineering geological conditions and the structure design schemes, the construction schemes and monitoring measurement projects of large-span gravel surrounding-rock tunnel were determined to ensure the safety of tunnel construction. This paper provides a complete example scheme for the design and construction of the main structure of the large-span IV class surrounding-rock tunnel, which provides a reference for similar projects in the future.

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Erratum to: Analytical Solutions of Cracks Emanating from an Elliptic Hole in an Infinite Plate under Tension (Chinese Journal of Mechanical Engineering, (2014), 27, 5, (1057-1063), 10.3901/CJME.2014.0526.300)

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Chinese Journal of Mechanical Engineering (English Edition) 2019年 1-1页

作者： Liu, Shuhong Duan, Shijie Department of Engineering Mechanics Shijiazhuang Tiedao University Shijiazhuang050043 China The Key Laboratory for Health Monitoring and Control of Large Structures of Hebei Province Shijiazhuang050043 China Department of Adult Education Shijiazhuang Tiedao University Shijiazhuang050043 China

The original version of this article unfortunately contained a mistake. The presentation of the DOI in printed version was incorrect. The corrected DOI is given below. DOI: 10.3901/CJME.2014.0526.300. © 2014, Chi...

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