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Numerical simulation and model test study of stability of surrounding rock for deep tunnel

Yantu Lixue/Rock and Soil Mechanics 2011年第SUPPL.2期32卷 615-620页

作者： Chen, Hao Ren, Wei-Zhong Li, Dan Xia, Bin-Wei State Key Laboratory of Geomechanics and Geotechnical Engineering Institute of Rock and Soil Mechanics Chinese Academy of Sciences Wuhan 430071 China College of Urban Construction Wuhan University of Science and Technology Wuhan 430065 China China Educ. Min. Key Lab. for Exploitation of Southwest Resources and Environ. Disaster Control Eng. Chongqing University Chongqing 400030 China

The physical model test of a tunnel is made on the triaxial model-test machine. The whole failure process is observed by applying full inner-spy photograph technology;with it the deformation and crack extension of key parts are studied. By using the strain measure technology, the strains of key parts of the surrounding rock are measured;according to this, the variability of the stresses of surrounding rock is studied. The measured values of the main physical and mechanical indices of the model material are closed to the theoretical values. Based on the mechanical property of the model material, the Mohr-Coulomb criterion with tension cut-off strain-softening model is established. The numerical simulation are worked with the same boundary condition as the model test;according to this, the plastic zone and the stress field of the surrounding rock are studied. We compare the failure process and the variation of stress of the surrounding rock of the model test with the numerical simulation and draw the conclusion that the two processes coincide with each other.

关键词： Strain

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Numerical simulation of electric field characteristics in response to water in-rush in working face

Numerical simulation of electric field characteristics in re...

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作者： Cheng, Jiulong Sui, Haibo Wang, Yuhe Cai, Mingfeng Jiang, Guoqing State Key Laboratory of Coal Resources and Safe Mining China University of Mining and Technology Beijing 100083 China Key Laboratory of Mine Disaster Prevention and Control Shandong University of Science and Technology Qingdao 266510 China Key Lab. for the Exploitation of Southwestern Rsrc. and the Environ. Disaster Control Engineering Ministry of Education Chongqing 400044 China CPECC East China Design Branch Qingdao 266071 China

ISBN: (纸本)9789078677383

According to the principle of resistivity detecting method and influencing law of resistivity in mining affected floor strata, different geoelectric models were constructed, such as model with water in-rush fractured zone in floor, working face advances to different distances, water in-rush after mining. Based on the "bipole-dipole" device, forward modeling was carried out by three-dimensional finite difference method. Apparent resistivity curves of different models can be obtained through numerical calculation and CT images can be obtained by processing the resistivity data with computerized tomography. Response characteristics of electric field in water in-rush working face can be analyzed by combing apparent resistivity curves with CT images. The results show that: good geological results could be achieved through numerical simulation of electric field response characteristics by using finite difference method and analyzing electric field characteristics of water in-rush in working face. This study provides theoretical basis for water in-rush detection using the resistivity method. © Atlantis Press, 2010.

关键词： Computerized tomography

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Study on anchored red sandstone's creep characteristic test and its constitutive model

Study on anchored red sandstone's creep characteristic test ...

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作者： Zhao, Tongbin Tan, Yunliang Liu, Shanshan Chen, Yunjuan Zhao, Zhigang Key Laboratory of Mine Disaster Prevention and Control Shandong University of Science and Technology Qingdao Shandong 266510 China College of Resources and Environmental Engineering Shandong University of Science and Technology Qingdao Shandong 266510 China Jinan Time Assay Testing Machine Co. Ltd. Jinan Shandong 250000 China Key Lab. for the Exploitation of Southwestern Rsrc. and the Environ. Disaster Control Engineering Ministry of Education 400044 China

ISBN: (纸本)9789078677383

In order to reveal deformation laws of anchored rock under long-term loads, in this paper, creep mechanical characteristics of anchored rock are analyzed, and anchorage constitutive model considering time effect is initially studied based on lab.ratory tests. Red sandstone of good homogeneity is used as anchored matrix, bamboo as the anchor, mixture of barite powder and rosin alcohol as the binder, then anchored red sandstone is made according to the similar criteria. Non-anchored and anchored specimens' indoor long-time (above 100h) creep test is conducted by RLJW-2000 rheology tester, The results show that, creep stress threshold of anchored rock is increased by about 30%σc, creep deformation at different stress level stage is significantly controlled, and anchored specimen's long-term intensity is increased by 5%∼10%σ c, which still has some capacity after destroyed. In addition, starting from the overall mechanical effect of anchor's reinforcement to rock, according to equivalent co-deformation principle, one-dimensional creep constitutive equation of anchored rock is established, the answer of anchored generalized Kelvin (B-K) model is derived and control mechanism on creep deformation of rock by bolt is analyzed. © Atlantis Press, 2010.

关键词： Creep

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DYNAMIC BEHAVIORS OF A FRACTIONAL ORDER VISCOELASTIC TWO-MEMBER TRUSS SYSTEM

DYNAMIC BEHAVIORS OF A FRACTIONAL ORDER VISCOELASTIC TWO-MEM...

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The Third International Conference on Dynamics,Vibration and control(第三届国际动力学、运动与控制学术会议)

作者： LI Yuan-ping ZHANG Wei Key Lab of Disaster Forecast and Control in Engineering Ministry of EducationChina (Jinan University) Guangzhou 510632 China Department of Electronic EngineeringJinan University Guangzhou 510632 China Department of Mechanics and Civil Engineering Jinan University

The dynamic behaviours of a viscoelastic two-member truss system, subjected to sinusoidal excitation, are investigated in this *** viscoelastic material was assumed to obey the fractional calculus constitutive *** dynamic equation and the numerical computation scheme suited for this nonlinear fractional viscoelastic system are deducted;the dynamic behaviours are investigated by means of numerical methods of nonlinear dynamics, such as time domain, phase diagram, Poincare map, and so *** is found that there are plenty of dynamical phenomena, such as periodicity, bifurcation, quasi-periodicity and chaos in the system and the dynamical character is greatly inflected by the varying of material parameters.

关键词： Fractional derivative Viscoelasticity Mises truss Chaos

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Parametric study on PCA-based algorithm for structural health monitoring

Parametric study on PCA-based algorithm for structural healt...

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International Conference on Prognostics and Health Management, PHM

作者： Ling Yu Jun-hua Zhu Liu-jie Cheri Key Lab of Disaster Forecast and Control in Engineering of Ministry of Education P. R. China Jinan University Guangzhou China Department of Mechanics and Civil Engineering Jinan University Guangzhou China Department of Mechanics and Civil Engineering Jinan University China

Using the measured frequency response function (FRF) data, a novel algorithm for structural health monitoring is proposed based on the principal component analysis (PCA) in this paper. First, the measured FRF data for a structure in both the healthy and the damaged states are used as the initial data. A PCA transformation is performed to obtain the features of an intact structure, in which an orthogonal transformation matrix packed by the first few eigenvectors of covariance matrix can be found. Further, the orthogonal transformation matrix is applied to the FRF data of damage structures to extract the features of structure in the damage state. By comparing the features of structure in the two states, a new damage feature index, namely the median values of the principal components (PCs), is proposed for structural health monitoring. Finally, the efficiency and robustness of the proposed method is illustrated and validated by using the real data provided by the Los Alamos National lab.ratory, USA. This paper aims at investigating the effect of parameters, such as training data selection, sample points and so on. The illustrated results show that the PCA-based algorithm is correct and effective for structural health monitoring. The new damage feature index can reflect the structure state as well. The algorithm is purely based on the FRF data and independent of structure model, which makes it applicable for structural health monitoring in situ.

关键词： Parametric study Condition monitoring Principal component analysis Covariance matrix Frequency measurement Frequency response Data mining Feature extraction Personal communication networks Robustness

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Application of Dempster-Shafer evidential theory in rock bolt testing

Application of Dempster-Shafer evidential theory in rock bol...

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作者： Sun, Xiaoyun Cheng, Jiulong Lv, Dandan Liu, Donghui School of Electrical and Electronics Engineering Shijiazhuang Tiedao University Shijiazhuang 050043 China Key Lab. for the Exploitation of Southwestern Rsrc. and the Environ. Disaster Control Engineering Ministry of Education Chongqing 400044 China State Key Laboratory of Coal Resources and Safe Mining China University of Mining and Technology Beijing 100083 China School of Electrical Engineering and Information Technology Hebei University of Science and Technology Shijiazhuang 050018 China

ISBN: (纸本)9789078677383

The basic concept and the fusion reasoning method of Dempster-Shafer evidential theory are introduced in this paper, by which the basic probability assignment testing the rock bolt is gained. The tested signal with different exciting frequencies is decomposed by HHT method, coefficients in useful signal dominative layer are used to be data fusion signal, and the Dempster-Shafer evidential theory is used to solve the rock bolt inspection problem. The result shows the effectiveness of Dempster-Shafer evidential theory method. © Atlantis Press, 2010.

关键词： Rock mechanics

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Analysis of solid-fluid coupling for tunnel excavation in complicated fractured rock masses

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Tumu Jianzhu yu Huanjing Gongcheng/Journal of Civil, Architectural and Environmental engineering 2010年第2期32卷 35-39+52页

作者： Zhao, Yu Lu, Yi-Yu Huang, Cheng Kang, Yong College of Civil Engineering Chongqing University Chongqing 400044 China Key Lab. for the Exploitation of Southwestern Resources and Environmental Disaster Control Eng. Chongqing University Chongqing 400044 China Key Laboratory of Rock and Soil Mechanics Institute of Rock and Soil Mechanics Chinese Acad. of Sci. Wuhan 430071 China

When tunnels are through water-bearing section of fractured rock mass, a complex interaction process between rock mass deformation and fluid transportation is one of the most important reasons for water gushing, water bursting and mud bursting. To study the rock mass deformation and fluid transportation in tunnel excavation under complex geological conditions, a hydraulic model of complex crack rock mass was established from the relationship between the crack growth degree of surrounding rock in deep buried tunnel and the engineering scale, with which fracture network of different levels in rock mass could be considered simultaneously. Furthermore, a computer Fortran program was put forward to simulate the solid-fluid coupling of excavation process of a deep buried tunnel. And it was found that the principal fractures had strong flowing action and network fractures had storage function and lag effect in seepage area. And the yield area of surrounding rock was increased under the coupling of seepage field and stress field.

关键词： Fracture

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THEORETICAL MODEL ON INTERFACE FAILURE MECHANISM OF REINFORCED CONCRETE CONTINUOUS BEAM STRENGTHENED BY FRP

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Acta Mechanica Solida Sinica 2009年第2期22卷 161-170页

作者： Hong Yuan Zifeng Lin MOE Key Lab of Disaster Forecast and Control in Engineering Institute of Applied Mechanics Jinan University Guangzhou 510632 China

Fiber reinforced polymer （FRP） composites are increasingly being used for the re-pair and strengthening of deteriorated concrete structural components through adhesive bonding of prefabricated strips/plates and the wet lay-up of fabric. Interfacial bond failure modes have attracted the attention of researchers because of the importance. The objective of the present study is to analyse the interface failure mechanism of reinforced concrete continuous beam strength-ened by FRP. An analytical solution has been firstly presented to predict the entire debonding process of the model. The realistic bi-linear bond-slip interfacial law was adopted to study this problem. The crack propagation process of the loaded model was divided into four stages （elastic,elastic-softening,elastic-softening-debonded and softening-debonded stage）. Among them,elastic-softening-debonded stage has four sub-stages. The equations are solved by adding suitable stress and displacement boundary conditions. Finally,critical value of bond length is determined to make the failure mechanism in the paper effective by solving the simultaneously linear algebraic equations. The interaction between the upper and lower FRP plates can be neglected if axial stiffness ratio of the concrete-to-plate prism is large enough.

关键词： FRP interface bond-slip law critical length continuous beam ultimate load

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Dynamic FE simulation of large-scale single-layer spherical shell with viscoelastic dampers

Dynamic FE simulation of large-scale single-layer spherical ...

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2009 Joint International Conference on Modelling and Simulation

作者： Yuan, Ping Li Wei, Zhang Key Lab. of Disaster Forecast and Control in Engineering Ministry of Education China Jinan University China Department of Mechanics and Civil Engineering Jinan University Guangzhou 510632 China

ISBN: (纸本)9781846260612

A vibration reduction system of viscoelastic dampers is introduced into Kewitte single-layer latticed spherical shell (D=60m). Through dynamic FE simulation, the stability of controlled shell and the correspondent uncontrolled one is compared. The different vibration schemes with initial geometric imperfection under different earthquake loadings are especially investigated. The results show that Liapunov stability of controlled shell with viscoelastic dampers can be evidently improved when compared with the uncontrolled shell;the vibration reduction is more obvious when considering the initial geometric imperfection of the shell. The damper's parameters have great influence on the vibration control effort.

关键词： Stability

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Studies on wavelet packet-based crack detection for a beam under the moving load

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key engineering Materials 2009年 413-414卷 285-290页

作者： Weiwei, Zhang Zhihua, Wang Hongwei, Ma College of Science and Engineering Jinan University Guangzhou 510632 China The Key Lab of Disaster Forecast and Control in Engineering Ministry of Edu. of China 510632 China Institute of Applied Mechanics Taiyuan University of Technology Taiyuan 030024 China

The objective of this study is to show the potential of the crack detection method based on Wavelet Packet Transform (WPT), which is depending on the response at a single point on a beam subject to moving load. In this paper, an A-SYS model of a cracked beam is established. The moving load is transient analyzed by shifting the point of the concentrated force. The response at mid-span of the beam is calculated and wavelet packet transformed. The crack on the beam can be found by the abnormal signal in WPT branches. The size is also estimated by a defined damage index (Dindex) which relates to the energy of the abnormal signal. Finally, the effects of both crack location and wavelet selection on Dindex are discussed in detail.

关键词： Damage detection

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