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Vertical drainage capacity of new electrical drainage board on improvement of super soft clayey ground

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Journal of Central South University 2015年第10期22卷 4027-4034页

作者：沈扬励彦德黄文君徐海东胡品飞 Key Laboratory of Ministry of Education for geomechanics and Embankment Engineering Hohai University Huahong Full Electro-osmosis Technologies Co. Ltd

As an advanced polymer composites electro-kinetic geosynthetics, the electro-osmotic vertical drainage(EVD) board could drain water quickly and accelerate consolidation process. However, the drainage rate was mainly impacted by the vertical drainage capability. Therefore, vertical drainage capability at the top of EVD board was theoretically analyzed. Basic requirements for drainage at the top of the board were summed up, as well as the formula of anode pore pressure when losing the vertical drainage capability. Meanwhile, a contrast test on the top and bottom drainage capacities was conducted. In use of the advanced EVD board, the voltage potential and pore pressure of anode were measured. Moreover, the derived formulas were verified. The result shows that the decrease of electric force gradient had an observable impact on the drainage capability. There was nearly no difference between the energy consumption for the two drainage methods. Although a little less water was discharged, the top drainage method had more advantages, such as high initial drainage velocity, few soil cracks, low anode water content and high soil strength. All of these show that the super soft soil ground could be consolidated quickly in use of the advanced EVD board through the top drainage. The top drainage method could efficiently improve the drainage effect, decrease the energy consumption and speed up the project proceeding.

关键词： electro-osmotic vertical drainage(EVD) board vertical drainage capacity potential gradient pore pressure around anode

Mechanics criterion and factors affecting overburden stability in solid dense filling mining

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International Journal of Mining Science and Technology 2017年第3期27卷 407-413页

作者： Sun Jian School of Energy and Safety Anhui University of Science & Technology State Key Laboratory for geomechanics & Deep Underground Engineering China University of Mining & Technology

The effect of controlling strata movement in solid filling mining depends on the filling rate of the goal. However, the mechanical property of the overburden in the backfill stope and the designed size of the backfill mining workface should also be considered. In this study, we established a main roof strata model with loads in accordance with the theory of key strata to investigate the stability of the overburden in solid dense filling mining. We analyzed the stress distribution law of the main roof strata based on elastic thin plate theory. The results show that the position of the long side midpoint of the main roof strata failed more easily because of tensile yield, indicating that this position is the area where failure is likely to occur more easily. We also deduced the stability mechanics criterion of the main roof strata based on tensile yield criterion. The factors affecting the stability of the overburden in solid dense filling mining were also analyzed, including the thickness and elasticity modulus of the main roof strata, overlying strata loads, advanced distance and length of workface, and elastic foundation coefficient of backfill body. The research achievements can provide an important theoretical basis for determining the designed size of the solid dense filling mining workface.

关键词： Filling mining Strata movement Stability control Influencing factors Size design

Performance of marine clay stabilised with vacuum pressure: Based on Queensland experience

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Journal of Rock Mechanics and Geotechnical Engineering 2019年第3期11卷 598-611页

作者： Buddhima Indraratna Cholachat Rujikiatkamjorn Pankaj Baral Jayantha Ameratunga Industrial Transformation Training Centre(ITTC)for advanced Technologies in Rail Track Infrastructure&Centre for geomechanics and Railway Engineering(CGRE) School of CivilMining and Environmental EngineeringUniversity of WollongongWollongong CityNSW 2522Australia School of Civil Mining and Environmental EngineeringUniversity of WollongongWollongong CityNSW 2522Australia Centre for geomechanics and Railway Engineering University of WollongongWollongong CityNSW 2522Australia Golder Associates Pty Ltd. MiltonQueensland 4064Australia

Stabilising soft marine clay and estuarine soils via vacuum preloading has become very popular in Australasia over the past decades because it is a cost-effective and time-efficient *** recent times,new land on areas outside but adjacent to existing port amenities,the Fisherman Islands at the Port of Brisbane(POB),was reclaimed to cater for an increase in trade activities.A vacuum preloading method combined with surcharge to stabilise the deep layers of soil was used to enhance the application of prefabricated vertical drains(PVDs).This paper describes the performance of this combined surcharge fill and vacuum system under the embankment and also compares it with a surcharge loading system to demonstrate the benefits of vacuum pressure over conventional *** performance of this embankment is also presented in terms of field monitoring data,and the relative performance of the vacuum together with non-vacuum systems is *** analytical solution to radial consolidation with time-dependent surcharge loading and vacuum pressure is also presented in order to predict the settlement and associated excess pore water pressure(EPWP)of deposits of thick soft clay.

关键词： Soft clay Prefabricated vertical drains(PVDs) Vacuum consolidation Membrane-less system Membrane system

Reliability Analysis of Reinforcement Based on GM(1,1)-Markov Semi-immersion Test

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Journal of Wuhan University of Technology(Materials Science) 2024年第5期39卷 1177-1187页

作者： FU Yong QIAO Hongxia HAKUZWEYEZU Theogene School of Civil Engineering Lanzhou University of TechnologyLanzhou 730050China Gansu advanced Civil Engineering Materials Engineering Research Center Lanzhou 730050China State Key Laboratory of geomechanics and Geotechnical Enginering Institute of Rock and Soil MechanicsChinese Academy of SciencesWuhan 430071China Civil Engineering Department University of Chinese Academy of SciencesBeijing 100049China

To investigate the corrosion degradation law and service life of reinforced concrete in various salt solution environments,reinforced concrete specimens were semi-immersed in 3%Na_(2)CO_(3)(N3-0-0),3%Na_(2)CO_(3)+3%NaCl(N3-Cl3-0)and 3%Na_(2)CO_(3)+3%NaCl+3%Na_(2)SO_(4)(N3-Cl3-S3)salt *** electrochemical workstation was used for regular non-destructive testing,and the polarization curve and related electrochemical parameters were used as the macroscopic durability evaluation indicators,while microscopic analysis of steel bar corrosion products was performed in combination with SEM and *** addition,the corrosion current density degradation model of GM(1,1)was established and compared with the modified GM(1,1)-Markov degradation *** results showed that the prediction error of the GM(1,1)-Markov model was smaller and more accurate than that of GM(1,1).The reinforced concrete specimens in the N3-0-0,N3-Cl3-0 and N3-Cl3-S3 solutions reached the failure state in 3.08,1.67,and 2.30 years,respectively,as predicted by the GM(1,1)-Markov *** to ESM and EDS microscopic analysis of reinforcement,carbonate had no significant effect on reinforcement corrosion,chloride ions played a dominant role in reinforcement corrosion,and sulfate ion improved concrete's resistance to chloride ion *** on GM(1,1)-Markov model,the failure and damage of reinforced concrete in saline soil areas can be quantitatively evaluated in the whole life cycle,which provides a theoretical basis for the early maintenance or reinforcing of reinforced concrete.

关键词： salt solution semi-immersion corrosion current density GM(1,1)-Markov

Influence of advanced engineering measures on displacement and stress field of surrounding rock in tunnels crossing active strike-slip faults

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Frontiers of Structural and Civil Engineering 2023年第10期17卷 1477-1501页

作者： Hui ZHOU Jiancheng XIAO Manchao HE Jingjing LU Zhigang TAO Futong XU Congcong HOU State Key Laboratory of geomechanics and Geotechnical Engineering Institute of Rock and Soil MechanicsChinese Academy of SciencesWuhan 430071China School of Engineering Science University of Chinese Academy of SciencesBeijing 100049China State Key Laboratory for geomechanics and Deep Underground Engineering China University of Mining and TechnologyBeijing 100083China School of Mechanics and Civil Engineering China University of Mining and TechnologyBeijing 100083China

Based on significant improvements in engineering materials,three advanced engineering measures have been proposed-super anchor cables,high-strength concrete anti-fault caverns,and grouting modification using high-strength concrete-to resist fault dislocation in the surrounding rock near tunnels crossing active strike-slip ***,single-or multiple-joint advanced engineering measures form the local rock mass-anti-fault(LRAF)method.A numerical method was used to investigate the influence of LRAF methods on the stress and displacement fields of the surrounding rock,and the anti-fault effect was ***,the mechanism of action of the anchor cable was verified using a three-dimensional numerical *** numerical results indicated that the anchor cable and grouting modification reduced the displacement gradient of the local surrounding rock near the tunnels crossing ***,anchor cable and grouting modifications changed the stress field of the rock mass in the modified *** tensile stress field of the rock mass in the modified anchor cable area was converted into a compressive stress *** stress field in the modified grouting area changed from shear stress in the fault slip direction to tensile stress in the axial tunnel *** anti-fault cavern resisted the dislocation displacement and reduced the maximum dislocation magnitude,displacement gradient,and shear *** the three advanced engineering measures,the anchor cable was the core of the three advanced engineering *** anchor cable,combined with other LRAF measures,can form an artificial safety island at the cross-fault position of the rock mass to protect the *** research results provide a new supporting idea for the surrounding rock of tunnels crossing active strike-slip faults.

关键词： anti-fault effect engineering measures LRAF method stress and displacement field tunnel-crossing active faults

An effective method for laboratory acoustic emission detection and location using template matching

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Journal of Rock Mechanics and Geotechnical Engineering 2022年第5期14卷 1642-1651页

作者： Xinglin Lei Tomohiro Ohuchi Manami Kitamura Xiaying Li Qi Li National Institute of advanced Industrial Science and Technology(AIST) Tsukuba305-8567Japan Geodynamics Research Center Ehime UniversityMatsuyama790-8577Japan State Key Laboratory of geomechanics and Geotechnical Engineering Institute of Rock and Soil MechanicsChinese Academy of SciencesWuhan430071China University of Chinese Academy of Sciences Beijing100049China

In this paper, a template matching and location method, which has been rapidly adopted in microseismic research in recent years, is applied to laboratory acoustic emission(AE) monitoring. First, we used traditional methods to detect P-wave first motions and locate AE hypocenters in three dimensions. In addition, we selected events located with sufficient accuracy(normally corresponding AE events of relatively larger energy, showing clear P-wave first motion and a higher signal-to-noise ratio in most channels) as template events. Then, the template events were used to scan and match other poorly located events in triggered event records or weak events in continuous records. Through crosscorrelation of the multi-channel waveforms between the template and the event to be detected, the weak signal was detected and located using a grid-searching algorithm(with the grid centered at the template hypocenter). In order to examine the performance of the approach, we calibrated the proposed method using experimental data of different rocks and different types of experiments. The results show that the proposed method can significantly improve the detection capability and location accuracy, and can be applied to various laboratory and in situ experiments, which use multi-channel AE monitoring with waveforms recorded in either triggering or continuous mode.

关键词： Acoustic emission Template matching and location Waveform cross-correlation Grid search

Simulation of failure process of jointed rock

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Journal of Central South University of Technology 2008年第6期15卷 888-894页

作者：张秀丽焦玉勇赵坚 State Key Laboratory of geomechanics and Geotechnical Engineering Institute of Rock and Soil MechanicsChinese Academy of Sciences Ecole Polytechnique Federale de Lausanne Rock Mechanics Laboratory

A modified discontinuous deformation analysis (DDA) algorithm was proposed to simulate the failure behavior of jointed rock. In the proposed algorithm, by using the Monte-Carlo technique, random joint network was generated in the domain of interest. Based on the joint network, the triangular DDA block system was automatically generated by adopting the advanced front method. In the process of generating blocks, numerous artificial joints came into being, and once the stress states at some artificial joints satisfy the failure criterion given beforehand, artificial joints will turn into real joints. In this way, the whole fragmentation process of rock mass can be replicated. The algorithm logic was described in detail, and several numerical examples were carried out to obtain some insight into the failure behavior of rock mass containing random joints. From the numerical results, it can be found that the crack initiates from the crack tip, the growth direction of the crack depends upon the loading and constraint conditions, and the proposed method can reproduce some complicated phenomena in the whole process of rock failure.

关键词： discontinuous deformation analysis jointed rock rock failure Monte-Carlo technique random joint network advancing front method triangular block system

Universality of slip avalanches in a ductile Fe-based bulk metallic glass

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Journal of Iron and Steel Research International 2017年第4期24卷 366-371页

作者： Jiao-jiao Li Jun-wei Qiao Karin A.Dahmen Wei-ming Yang Bao-long Shen Ming-wei Chen Laboratory of Applied Physics and Mechanics of advanced Materials College of Materials Science and EngineeringTaiyuan University of TechnologyTaiyuan 030024ShanxiChina Key Laboratory of Interface Science and Engineering in advanced Materials Ministry of EducationTaiyuan University of TechnologyTaiyuan 030024ShanxiChina Department of Physics University of Illinois at Urbana-ChampaignIllinois 61801USA State Key Laboratory for geomechanics and Deep Underground Engineering School of Mechanics and Civil EngineeringChina University of Mining and TechnologyXuzhou 221116JiangsuChina School of Materials Science and Engineering Southeast UniversityNanjing 211189JiangsuChina advanced Institute for Materials Research Tohoku UniversitySendal 980-8577Japan

Intermittent serrated flows of a novel ductile Fe60Ni20P13C7 bulk metallic glass（BMG）at variant strain rates were investigated by statistics *** and clutter distribution of slip-avalanche magnitudes are displayed during stable plastic flows at strain rates of 2×10-4 s-1 and 5×10-5 s-1,respectively,which means that serration behavior depends on the strain ***,the remarkable agreement between measured slip-avalanche magnitudes and the scaling behavior,i.e.a universal complementary cumulative distribution function（CCDF）predicted by mean-field theory（MFT）model,indicates that the plasticity of the present Fe-based BMGs can be tuned by imposed strain rates：Smax^6）ε-λ.This tuned plasticity is elucidated with expended free-volume ***,the scaling behavior of serrated flows for other strain rates can be predicted as well.

关键词： Bulk metallic glass Slip avalanche Plasticity Mean-field theory model Strain rate

Influence of bedding structure on stress-induced elastic wave anisotropy in tight sandstones

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Journal of Rock Mechanics and Geotechnical Engineering 2021年第1期13卷 98-113页

作者： Xiaying Li Xinglin Lei Qi Li Dianguo Chen State Key Laboratory of geomechanics and Geotechnical Engineering Institute of Rock and Soil MechanicsChinese Academy of SciencesWuhan430071China University of Chinese Academy of Sciences Beijing100049China National Institute of advanced Industrial Science and Technology(AIST) Tsukuba305-8567Japan Chongqing Dizhiyuan Geology and Engineering Testing Co. LtdChongqing401329China

To understand the evolution of stress-induced elastic wave anisotropy,three triaxial experiments were performed on sandstone specimens with bedding orientations parallel,perpendicular,and oblique to the maximum principal stress.P-wave velocities along 64 different directions on each specimen were monitored frequently to understand the anisotropy change at various stress levels by fitting Thomsen’s anisotropy *** results show that the elastic wave anisotropy is very sensitive to mechanical *** hydrostatic loading,the magnitude of anisotropy is reduced in all three ***,under deviatoric stress loading,the evolution of anisotropic characteristics(magnitude and orientation of the symmetry axis)is bedding orientation *** reversal occurs in specimens with bedding normal/oblique to the maximum principal stress.P-wave anisotropyε0 is linearly related to volumetric strain Sv and dilatancy,indicating that stress-induced redistribution of microcracks has a significant effect on P-wave velocity *** closure of initial cracks and pores aligned in the bedding direction contributes to the decrease of the ***,opening of new cracks,aligned in the maximum principal direction,accounts for the increase of the *** experimental results provide some insights into the microstructural behavior under loading and provide an experimental basis for seismic data interpretation and parameter selection in engineering applications.

关键词： Elastic wave anisotropy Stress-induced anisotropy Anisotropy reversal Bedding orientation Microstructure Tight sandstone