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Shear mechanical properties and frictional sliding responses of rough joint surfaces under dynamic normal displacement conditions

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Journal of Central South University 2024年第7期31卷 2393-2410页

作者： ZHU Qiang YIN Qian TAO Zhi-gang HE Man-chao ZHENG Bo-wen JING Hong-wen REN Shu-lin ZHANG Qiang MENG Bo BAI Dong-feng WU Sai-sai WU Jiang-yu State Key Laboratory of Intelligent construction and Healthy Operation and Maintenance of Deep Underground engineering Xuzhou 221116China State Key Laboratory for Geomechanics&Deep Underground engineering China University of Mining and Technology(Beijing)Beijing 100083China Key Laboratory of Shale Gas and Geoengineering Institute of Geology and GeophysicsChinese Academy of SciencesBeijing 100029China cccc First highway Survey and Design Research Institute co. Ltd.Xi’an 710075China

A comprehensive understanding of the dynamic frictional characteristics in rock joints under high normal load and strong confinement is essential for ensuring the safety of deep engineering construction and mitigating geological *** study conducted shear experiments on rough rock joints under displacement-controlled dynamic normal loads,investigating the shear behaviors of joints across varying initial normal loads,normal loading frequencies,and normal loading *** results showed that the peak/valley shear force values increased with initial normal loads and normal loading frequencies but showed an initial increase followed by a decrease with normal loading *** normal loading can either increase or decrease shear strength,while this study demonstrates that higher frequencies lead to enhanced *** initial normal loading and normal loading frequency result in a gradual decrease in joint roughness coefficient(JRC)values of joint surfaces after *** correlations existed between frictional energy dissipation and peak shear forces,while post-shear joint surface roughness exhibited a negative correlation with peak shear forces through linear regression *** study contributes to a better understanding of the sliding responses and shear mechanical characteristics of rock joints under dynamic disturbances.

关键词： dynamic normal displacement shear strength variations phase lag phenomenon stick-slip

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Mechanical responses of underground carriageway structures due to construction of metro tunnels beneath the existing structure:A case study

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Deep Underground Science and engineering 2024年第2期3卷 231-246页

作者： Xin Han Fei Ye Xingbo Han Chao Ren Jing Song Ruliang Zhao School of highway Chang'an UniversityXi'anChina Shandong Province Transportation Planning and Design Institute JinanChina China Water Resources Beifang Investigation Design and Research Co.Ltd.TianjinChina

To understand the mechanical response pattern of the existing structure and ground due to the construction of metro tunnels underneath,the finite difference method is adopted to study the torsional deformation and stress variation of the existing structure and the effect of underground carriageway structures on the surface *** curves of the maximum differential subsidence,torsion angle,and distortion of the cross-section of the existing structure show two peaks in succession during traversing of two metro tunnels beneath *** torsion angle of the existing structure changes when the two tunnels traverse beneath it in opposite *** first traversing of the shield tunnel mainly induces the magnitude variation in torsional deformation of the existing structure,but the second traversing of the subsurface tunnel may cause a dynamic change in the magnitude and form of torsional deformation in the existing *** shielding effect can reduce the surface subsidence caused by metro tunnel excavation to a certain extent,and the development trend of subsidence becomes slower as the excavation continues.

关键词： metro tunnel numerical simulation structural deformation surface subsidence underground carriageway structure

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Undrained Bearing Capacity of Spudcan Under combined Loading

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China Ocean engineering 2011年第1期25卷 15-30页

作者：王立忠舒恒李玲玲国振 college of Civil engineering and Architecture Zhejiang University cccc second highway consultants co.ltd.

The bearing capacities of spudcan foundation under pure vertical （/1）, horizontal （H）, moment （M） loading and the combined loading are studied based on a series of three-dimensional finite element analysis. The effects of embedment ratio and soil non-homogeneity on the bearing capacity are investigated in detail. The capacities of spudcan under different pure loading are expressed in non-dimensional bearing capacity factors, which are compared with published results. Ultimate limit states under combined loading are presented by failure envelopes, which are expressed in terms of dimensionless and normalized form in three-dimensional load space. The comparison between the presented failure envelopes and available published numerical results reveals that the size and shape of failure envelopes are dependent on the embedment ratio and the non-homogeneity of the soil.

关键词： soft clay spudcan bearing capacity combined loading finite element

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Ultraviolet Radiation Aging of Tafpack-Super Modified Porous Asphalt concrete

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武汉理工大学学报 2010年第17期32卷 206-209页

作者： HONG W H WU S P XIE J cccc second highway engineering co.ltd Xi'an 710000China Key Laboratory of Silicate Materials Science and engineering Wuhan University of TechnologyWuhan 430070China

Ultraviolet aging of porous asphalt concrete is more serious than that of dense-grade concrete,attributing to its relatively high air void structure. And Tafpack-Super (TPS) is widely used as an asphalt viscosifier. For the purpose of determining the effect of TPS content on resistance to ultraviolet aging,TPS powder was added to base asphalt in various weight ratios (0%,4%,8%,12% and 16%). After mixing,the loose mixtures were short-term aged and then put in the Indoor Accelerated Ultraviolet Radiation Aging Oven for several particular times and then were compacted by Gyratory compactor at 20%±2% air void. The specimens were tested and recorded by means of indirect tensile strength (ITS) to quantify the aging extent. The results show that 8% TPS by weight is the optimum content of base asphalt on resistance to ultraviolet aging. And the ITS of mixtures with different binder reach a peak value for approximately 2 h ultraviolet irradiation.

关键词： tafpack-super ultraviolet radiation ageing indirect tensile strength

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Seismic response analysis of road vehicle-bridge system for continuous rigid frame bridges with high piers

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Earthquake engineering and engineering Vibration 2012年第4期11卷 593-602页

作者： Li Yongle Chen Ning Zhao Kai Liao Haili Department of Civil engineering Southwest Jiaotong University cccc highway consultants co. Ltd.

The objective of this study is to investigate the effects of earthquakes on road vehicle-bridge coupling vibration systems. A two-axle highway freight vehicle is treated as a 13 degree-of-freedom system composed of several rigid bodies, which are connected by a series of springs and dampers. The framework of the earthquake-vehicle-bridge dynamic analysis system is then established using an earthquake as the extemal excitation. The equivalent lateral contact force serves as the judgment criteria for sideslip accidents according to reliability theory. The entire process of the vehicle crossing the bridge is considered for a very high pier continuous rigid frame bridge. The response characteristics of the vehicle and the bridge are discussed in terms of various parameters such as earthquake ground motion, PGA value of the earthquake, incident angle, pier height, vehicle speed and mass. It is found that seismic excitation is the most influential factor in the responses of the vehicle-bridge system and that the safety of vehicles crossing the bridge is seriously impacted by the dual excitations of earthquake and bridge vibration.

关键词： vehicle-bridge system coupling vibration seismic effects safety dynamic response

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Improved plane layout of stabilizing piles based on the piecewise function expression of the irregular driving force

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Journal of Mountain Science 2018年第4期15卷 871-881页

作者： LIU Wen-qiang LI Qun LU Jian LI Chang-dong YAO Wen-min ZENG Jiang-bo Faculty of engineering China University of Geosciences cccc second highway consultants co. Ltd. Shenzhen Geotechnical Investigation & Surveying Institute co. Ltd.

The paper presents an improved plane layout for stabilizing piles based on a proposed piecewise function expression for the irregular driving force. Based on the specific morphological characteristics of a highway landslide, the piecewise function is used to calculate the irregular driving force by dividing the landslide into several ***, the reasonable layout range and pile spacing can be obtained based on the piecewise function expression of the irregular driving force and on relevant research results of the plane layout for stabilizing piles. Therefore, an improved plane layout of stabilizing piles is presented in consideration of a piecewise function expression of the irregular driving force. A highway landslide located in eastern Guizhou Province, China, is analyzed as a case study using the proposed method. The results demonstrate that the theory presented in this paper provides improved economic benefits and can reduce the requirednumber of stabilizing piles by 28.6% compared with the conventional plane layout scheme.

关键词： highway landslide Driving force Piecewise function Stabilizing pile Plane layout

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Hurricane damage assessment for residential construction considering the non-stationarity in hurricane intensity and frequency

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Acta Oceanologica Sinica 2016年第12期35卷 110-118页

作者： WANG Cao LI Quanwang PANG Long ZOU Aming ZHANG Long Department of Civil engineering Tsinghua University cccc highway consultants co. Ltd.

Natural hazards such as hurricanes may cause extensive economic losses and social disruption for civil structures and infrastructures in coastal areas, implying the importance of understanding the construction performance subjected to hurricanes and assessing the hurricane damages properly. The intensity and frequency of hurricanes have been reported to change with time due to the potential impact of climate *** this paper, a probability-based model of hurricane damage assessment for coastal constructions is proposed taking into account the non-stationarity in hurricane intensity and frequency. The nonhomogeneous Poisson process is employed to model the non-stationarity in hurricane occurrence while the non-stationarity in hurricane intensity is reflected by the time-variant statistical parameters(e.g., mean value and/or standard deviation), with which the mean value and variation of the cumulative hurricane damage are evaluated explicitly. The Miami-Dade county, Florida, USA, is chosen to illustrate the hurricane damage assessment method proposed in this paper. The role of non-stationarity in hurricane intensity and occurrence rate due to climate change in hurricane damage is investigated using some representative changing patterns of hurricane parameters.

关键词： hurricane damage assessment intensity frequency non-stationarity climate change

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Different Curing Systems on Mechanical Properties of Ultra-High Performance concrete with coarse Aggregate

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Journal of Donghua University(English Edition) 2017年第4期34卷 492-497页

作者：赵秋杨明庄一舟聂宇 college of Civil engineering Fuzhou University cccc second highway consultants co. Ltd.

High durability and high tensile strength makes ultra-high performance concrete( UHPC) an ideal material for bridges,while its early shrinkage in the construction of cast-in-situ mass concrete leads structure crack-easily,which restricts the application of UHPC in deck system. Whether reasonable amount of coarse aggregate can influence the strength of UHPC and improve the shrinkage performance or reduce the cost is still in doubt. Besides,in order to improve its constructability and workability, whether autoclaved curing system of UHPC can be changed remains to be further researched. In response to these circumstances, a systematic experimental study on the strength of UHPC mixed with coarse aggregate in different ratios has been presented in this paper. The three curing systems,namely standard curing,180-200 ℃/1. 1 MPa autoclaved curing,and hot water curing were tested to reveal the relationship between UHPC's properties and curing systems,and the UHPC ' s microstructure was also preliminarily studied by scanning electron microscope( SEM). The experimental research can draw the following conclusions. Under the condition of the same mix ratio, autoclaved curing guarantees the highest compressive strength,followed by hot water curing and standard curing. The compressive strength of concrete increases with the temperature in the range of 25 to 90 ℃ hot water curing,and high temperature in precuring period can speed up the strength development of UHPC,but the sequence of precuring period does not obviously affect the results. In 90 ℃ hot water and autoclaved curing,the strength is over 150 MPa,and it has little relation with gravel ratio. While the value increases first and then decreases in a lower temperature curing with the increasing of gravel amount,even only about 80 MPa at room temperature. The strength increases moderately along with the increase of the curing age by standard curing,especially in the initial stage.

关键词： ultra-high performance concrete(UHPC) coarse aggregate curing system strength microstructure

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Structural damage assessment using improved Dempster-Shafer data fusion algorithm

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Earthquake engineering and engineering Vibration 2019年第2期18卷 395-408页

作者： Ding Yijie Yao Xiaofei Wang Sheliang Zhao Xindong School of Civil engineering Xi'an Univ.of Arch.& Tech. cccc First highway consultants co. Ltd.

As an efficient tool in handling uncertain issues, Dempster-Shafer evidence theory has been increasingly used in structural health monitoring and damage detection. In applications, however, Dempster-Shafer evidence theory sometimes leads to counter-intuitive results. In this study, a new fusion algorithm of evidence theory is put forward to address various counter-intuitive problems and manage the reliability difference of the evidence. The proposed algorithm comprises the following aspects:(1) Dempster's combination rule is generalized by introducing the concept of evidence ullage. The new rule allows classical Dempster's rule and can resolve counter-intuitive problems cause by evidence conflict and evidence compatibility;(2) a reliability assessing method based on a priori and posterior knowledge is proposed. compared with conventional reliability assessment, the proposed method can reflect the actual evidence reliabilities and can efficiently reduce decision risk. Numerical examples confirm the validity and utility of the proposed algorithm. In addition, an experimental investigation on a spatial truss structure is carried out to illustrate the identified ability of the proposed approach. The results indicate that the fusion algorithm has no strict request on the accuracy and consistency of evidence sources and can efficiently enhance diagnostic accuracy.

关键词： Dempster-Shafer evidence theory damage detection evidence confl ict evidence reliability spatial truss structure

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Intelligent feedback analysis on a deep excavation for the gravity anchorage foundation of a super suspension bridge

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岩石力学与工程学报 2019年第A1期38卷 2898-2912页

作者： RAN Tao LIU Daan MEI Songhua WANG Weiwei TAN Lihua Institute of Geology and Geophysics Chinese Academy of Sciences University of Chinese Academy of Sciences Zhongnan engineering co. Ltd. cccc First highway engineering co. Ltd.

In order to ensure the construction safety of the 38.5 m deep excavation for the gravity anchorage foundation of Fuma Yangtze River Bridge, an intelligent feedback analysis was applied to this excavation project. First, a three-dimensional numerical model that simulating the construction process of the excavation was built,and the deformations of the supporting structures were calculated by the finite difference program FLAC3 D. Then,the non-linear mapping relationship between the geomechanical parameters and the excavation-induced displacements was established by the back-propagation neural network(BPNN). Last,the geomechanical parameters were optimized intelligently by the genetic algorithm(GA) based on the developed BPNN model and the measured displacements,and the deformations during the subsequent excavation stages were predicted based on the back-calculated parameters. The research results showed that:the back-calculated values of E1,μ1,c1,and φ1 of the completely weathered stratum,and E2 of the heavily weathered stratum were greater than the initial values,while the inversion value of E3 of the moderately weathered stratum was smaller than the initial value. The magnitudes and the variation tendencies of the predicted displacements were in good accordance with the measured displacements. At the end of the excavation,the retaining piles and the top beams had a maximum displacement of 15–20 mm,exhibiting a quite small magnitude as comparing with other case histories. Local concentration of shear stress mainly occurred at the soil-pile interface and at the toe of the excavation slope,and the plastic zones mainly appeared in the completely weathered stratum. After the completion of the excavation,there were no yielding elements in the model,and the convergence of the numerical computation was achieved,indicating the excavation was in a stable state. This study lays the basis for the subsequent construction and operation of the bridge,and offers a significant refe

关键词： foundations suspension bridge anchorage deep excavation parameter inversion deformation prediction intelligent feedback analysis

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