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Enhanced Hoek-Brown(H-B)criterion for rocks exposed to chemical corrosion
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作者 Hao Li Leo Pel +1 位作者 Zhenjiang You David Smeulders 《International Journal of Mining Science and Technology》 SCIE EI CAS CSCD 2024年第5期609-630,共22页
Underground constructions often encounter water environments,where water–rock interaction can increase porosity,thereby weakening engineering rocks.Correspondingly,the failure criterion for chemically corroded rocks ... Underground constructions often encounter water environments,where water–rock interaction can increase porosity,thereby weakening engineering rocks.Correspondingly,the failure criterion for chemically corroded rocks becomes essential in the stability analysis and design of such structures.This study enhances the applicability of the Hoek-Brown(H-B)criterion for engineering structures operating in chemically corrosive conditions by introducing a kinetic porosity-dependent instantaneous mi(KPIM).A multiscale experimental investigation,including nuclear magnetic resonance(NMR),X-ray diffraction(XRD),scanning electron microscopy(SEM),pH and ion chromatography analysis,and triaxial compression tests,is employed to quantify pore structural changes and their linkage with the strength responses of limestone under coupled chemical-mechanical(C-M)conditions.By employing ion chromatography and NMR analysis,along with incorporating the principles of free-face dissolution theory accounting for both congruent and incongruent dissolution,a kinetic chemical corrosion model is developed.This model aims to calculate the kinetic porosity alterations within rocks exposed to varying H+concentrations and durations.Subsequently,utilizing the generalized mixture rule(GMR),the kinetic porositydependent mi is formulated.Evaluation of the KPIM-enhanced H-B criterion using compression test data from 5 types of rocks demonstrated a high level of consistency between the criterion and the experimental results,with a coefficient of determination greater than 0.96,a mean absolute percentage error less than 4.84%,and a root-mean-square deviation less than 5.95 MPa.Finally,the physical significance of the porosity-dependent instantaneous mi is clarified:it serves as an indicator of a rock’s capacity to leverage the confining pressure effect. 展开更多
关键词 hoek-brown(H-B)criterion Instantaneous mi Kinetic porosity-dependency Chemical corrosion Compressive strength
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Three-dimensional limit variation analysis on the ultimate pullout capacity of the anchor cables based on the Hoek-Brown failure criterion
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作者 ZUO Shi ZHAO Lianheng HU Shihong 《Journal of Mountain Science》 SCIE CSCD 2024年第3期1036-1047,共12页
Only simplified two-dimensional model and a single failure mode are adopted to calculate the ultimate pullout capacity(UPC)of anchor cables in most previous research.This study focuses on a more comprehensive combinat... Only simplified two-dimensional model and a single failure mode are adopted to calculate the ultimate pullout capacity(UPC)of anchor cables in most previous research.This study focuses on a more comprehensive combination failure mode that consists of bond failure of an anchorage body and failure of an anchored rock mass.The three-dimensional ultimate pullout capacity of the anchor cables is calculated based on the Hoek-Brown failure criterion and variation analysis method.The numerical solution for the curvilinear function in fracture plane is obtained based on the finite difference theory,which more accurately reflects the failure state of the anchor cable,as opposed to that being assumed in advance.The results reveal that relying solely on a single failure mode for UPC calculations has limitations,as changes in parameter values not only directly impact the UPC value but also can alter the failure model and thus the calculation method. 展开更多
关键词 Anchor cable Ultimate pullout capacity(UPC) Failure model Variation analysis hoek-brown failure criterion
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Analysis on the turning point of dynamic in-plane compressive strength for a plain weave composite
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作者 Xiaoyu Wang Zhixing Li +2 位作者 Licheng Guo Zhenxin Wang Jiuzhou Zhao 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2024年第2期485-495,共11页
Experimental investigations on dynamic in-plane compressive behavior of a plain weave composite were performed using the split Hopkinson pressure bar. A quantitative criterion for calculating the constant strain rate ... Experimental investigations on dynamic in-plane compressive behavior of a plain weave composite were performed using the split Hopkinson pressure bar. A quantitative criterion for calculating the constant strain rate of composites was established. Then the upper limit of strain rate, restricted by stress equilibrium and constant loading rate, was rationally estimated and confirmed by tests. Within the achievable range of 0.001/s-895/s, it was found that the strength increased first and subsequently decreased as the strain rate increased. This feature was also reflected by the turning point(579/s) of the bilinear model for strength prediction. The transition in failure mechanism, from local opening damage to completely splitting destruction, was mainly responsible for such strain rate effects. And three major failure modes were summarized under microscopic observations: fiber fracture, inter-fiber fracture, and interface delamination. Finally, by introducing a nonlinear damage variable, a simplified ZWT model was developed to characterize the dynamic mechanical response. Excellent agreement was shown between the experimental and simulated results. 展开更多
关键词 Plain weave composite dynamic strength Quantitative criterion Turning point Failure mechanism
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Correction of dynamic Brazilian disc tensile strength of rocks under preloading conditions considering the overload phenomenon and invoking the Griffith criterion 被引量:1
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作者 Kaiwen Xia Yuchao Yu +1 位作者 Bangbiao Wu Wei Yao 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2023年第8期1986-1996,共11页
Dynamic tensile failure is a common phenomenon in deep rock practices,and thus accurately evaluating the dynamic tensile responses of rocks under triaxial pressures is of great significance.The Brazilian disc(BD)test ... Dynamic tensile failure is a common phenomenon in deep rock practices,and thus accurately evaluating the dynamic tensile responses of rocks under triaxial pressures is of great significance.The Brazilian disc(BD)test is the suggested method by the International Society for Rock Mechanics and Rock Engineering(ISRM)for measuring both the static and dynamic tensile strengths of rock-like materials.However,due to the overload phenomenon and the complex preloading conditions,the dynamic tensile strengths of rocks measured by the BD tests tend to be overestimated.To address this issue,the dynamic BD tensile strength(BTS)of Fangshan marble(FM)under different preloading conditions were measured through a triaxial split Hopkinson pressure bar(SHPB).The fracture onset in BD specimen was captured through a strain gage around the disc center.The discrepancy between the traditional tensile strength(TTS,determined by the peak load P_(f) of the BD specimen)and the nominal tensile strength(NTS,obtained from the load P_(i) when the diametral fracture commences in the tested BD specimen)was applied to quantitatively evaluating the overload phenomenon.The Griffith criterion was used to rectify the calculation of the tensile stress at the disc center under triaxial stress states.The results demonstrate that the overload ratio(s)increases with the loading rate(σ)and decreases with the hydrostatic pressure(σ_(s)).The TTS corrected by the Griffith criterion is independent of theσ_(s)due to the overload phenomenon,while the NTS corrected by the Griffith criterion is sensitive to both the andσ.Therefore,it is essential to modify the tensile stress in dynamic confined BD tests using both the overload correction and the Griffith criterion rectification to obtain the accurate dynamic BTS of rocks. 展开更多
关键词 dynamic brazilian disc test Overload phenomenon dynamic tensile strength Hydrostatic pressure Griffith criterion
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Two-dimensional face stability analysis in rock masses governed by the Hoek-Brown strength criterion with a new multi-horn mechanism 被引量:2
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作者 Junhao Zhong Xiaoli Yang 《International Journal of Mining Science and Technology》 SCIE EI CAS CSCD 2023年第8期963-976,共14页
The face stability problem is a major concern for tunnels excavated in rock masses governed by the Hoek-Brown strength criterion.To provide an accurate prediction for the theoretical solution of the critical face pres... The face stability problem is a major concern for tunnels excavated in rock masses governed by the Hoek-Brown strength criterion.To provide an accurate prediction for the theoretical solution of the critical face pressure,this study adopts the piecewise linear method(PLM)to account for the nonlinearity of the strength envelope and proposes a new multi-horn rotational mechanism based on the Hoek-Brown strength criterion and the associative flow rule.The analytical solution of critical support pressure is derived from the energy-work balance equation in the framework of the plastic limit theorem;it is formulated as a multivariable nonlinear optimization problem relying on 2m dependent variables(m is the number of segments).Meanwhile,two classic linearized measures,the generalized tangential technique(GTT)and equivalent Mohr-Coulomb parameters method(EMM),are incorporated into the analysis for comparison.Surprisingly,the parametric study indicates a significant improvement in support pressure by up to 13%compared with the GTT,and as expected,the stability of the tunnel face is greatly influenced by the rock strength parameters.The stress distribution on the rupture surface is calculated to gain an intuitive understanding of the failure at the limit state.Although the limit analysis is incapable of calculating the true stress distribution in rock masses,a rough approximation of the stress vector on the rupture surface is permitted.In the end,sets of normalized face pressure are provided in the form of charts for a quick assessment of face stability in rock masses. 展开更多
关键词 Face stability Piecewise linear method hoek-brown strength criterion Multi-horn rotational mechanism Limit analysis
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Strength criterion of composite solid propellants under dynamic loading 被引量:8
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作者 Zhe-jun Wang Hong-fu Qiang +1 位作者 Guang Wang Biao Geng 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2018年第5期457-462,共6页
Based on the dynamic loading(1-100 s^(-1)) experiments under different temperatures(223-298 K) and stress states, uniaxial and biaxial strength criterion of a Hydroxyl-terminated polybutadiene(HTPB)based composite sol... Based on the dynamic loading(1-100 s^(-1)) experiments under different temperatures(223-298 K) and stress states, uniaxial and biaxial strength criterion of a Hydroxyl-terminated polybutadiene(HTPB)based composite solid propellant were further investigated. These experiments were conducted through the use of a new uniaxial INSTRON testing machine, different new designed gripping apparatus and samples with different configurations. According to the test results, dynamic uniaxial tensile strength criterion of the propellant was directly constructed with the master curve of the uniaxial maximum tensile stress. Whereas, a new method was proposed to determine the dynamic uniaxial compressive strength of the propellant in this study. Then uniaxial compressive strength criterion of the propellant was constructed based on the related master curve. Moreover, it found that the uniaxial tensilecompressive strength ratio of the propellant is more sensitive to loading temperature under the test conditions. The value of this parameter is about 0.4 at room temperature, and it reduces to 0.2-0.3 at low temperatures. Finally, the theoretical biaxial strength criterion of HTPB propellant under dynamic loading was constructed with the unified strength theory, the uniaxial strength and the typical biaxial tensile strength. In addition, the theoretical limit lines of the principal stress plane for the propellant under dynamic loading at different temperatures were further plotted, and the scope of the limit line increases with decreasing temperature. 展开更多
关键词 STRENGTH criterion UNIFIED STRENGTH theory Composite solid PROPELLANT dynamic LOADING BIAXIAL tension
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A viscoelastic-plastic constitutive model with Mohr-Coulomb yielding criterion for sea ice dynamics 被引量:10
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作者 JI Shunying SHEN Hung Tao +2 位作者 WANG Zhilian SHEN H Hayley YUE Qianjin 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2005年第4期54-65,共12页
A new viscoelastic-plastic (VEP) constitutive model for sea ice dynamics was developed based on continuum mechanics. This model consists of four components: Kelvin-Vogit viscoelastic model, Mohr-Coulomb yielding cr... A new viscoelastic-plastic (VEP) constitutive model for sea ice dynamics was developed based on continuum mechanics. This model consists of four components: Kelvin-Vogit viscoelastic model, Mohr-Coulomb yielding criterion, associated normality flow rule for plastic rehololgy, and hydrostatic pressure. The numerical simulations for ice motion in an idealized rectangular basin were made using smoothed particle hydrodynamics (SPH) method, and compared with the analytical solution as well as those based on the modified viscous plastic(VP) model and static ice jam theory. These simulations show that the new VEP model can simulate ice dynamics accurately. The new constitutive model was further applied to simulate ice dynamics of the Bohai Sea and compared with the traditional VP, and modified VP models. The results of the VEP model are compared better with the satellite remote images, and the simulated ice conditions in the JZ20-2 oil platform area were more reasonable. 展开更多
关键词 sea ice dynamics constitutive model viscous plasticity viscoelastic-plastic model Molar-Coulomb criterion
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Rockburst criterion and evaluation method for potential rockburst pit depth considering excavation damage effect 被引量:1
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作者 Jinhao Dai Fengqiang Gong Lei Xu 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2024年第5期1649-1666,共18页
Excavation-induced disturbances in deep tunnels will lead to deterioration of rock properties and formation of excavation damaged zone(EDZ).This excavation damage effect may affect the potential rockburst pit depth.Ta... Excavation-induced disturbances in deep tunnels will lead to deterioration of rock properties and formation of excavation damaged zone(EDZ).This excavation damage effect may affect the potential rockburst pit depth.Taking two diversion tunnels of Jinping II hydropower station for example,the relationship between rockburst pit depth and excavation damage effect is first surveyed.The results indicate that the rockburst pit depth in tunnels with severe damage to rock masses is relatively large.Subsequently,the excavation-induced damage effect is characterized by disturbance factor D based on the Hoek-Brown criterion and wave velocity method.It is found that the EDZ could be further divided into a high-damage zone(HDZ)with D=1 and weak-damage zone(WDZ),and D decays from one to zero linearly.For this,a quantitative evaluation method for potential rockburst pit depth is established by presenting a three-element rockburst criterion considering rock strength,geostress and disturbance factor.The evaluation results obtained by this method match well with actual observations.In addition,the weakening of rock mass strength promotes the formation and expansion of potential rockburst pits.The potential rockburst pit depth is positively correlated with HDZ and WDZ depths,and the HDZ depth has a significant contribution to the potential rockburst pit depth. 展开更多
关键词 Deep tunnel ROCKBURST Rockburst pit Excavation damage effect hoek-brown criterion
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Limit load and failure mechanisms of a vertical Hoek-Brown rock slope
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作者 Jim Shiau Warayut Dokduea +1 位作者 Suraparb Keawsawasvong Pitthaya Jamsawang 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2024年第3期1106-1111,共6页
The problem considered in this short note is the limit load determination of a vertical rock slope.The classical limit theorem is employed with the use of adaptive finite elements and nonlinear programming to determin... The problem considered in this short note is the limit load determination of a vertical rock slope.The classical limit theorem is employed with the use of adaptive finite elements and nonlinear programming to determine upper and lower bound limit loads of a Hoek-Brown vertical rock slope.The objective function of the mathematical programming problem is such as to optimize a boundary load,which is known as the limit load,resembling the ultimate bearing capacity of a strip footing.While focusing on the vertical slope,parametric studies are carried out for several dimensionless ratios such as the dimensionless footing distance ratio,the dimensionless height ratio,and the dimensionless rock strength ratio.A comprehensive set of design charts is presented,and failure envelopes shown with the results explained in terms of three identified failure mechanisms,i.e.the face,the toe,and the Prandtl-type failures.These novel results can be used with great confidence in design practice,in particularly noting that the current industry-based design procedures for the presented problem are rarely found. 展开更多
关键词 Bearing capacity Rock slope Vertical slope Finite element limit analysis hoek-brown yield criterion
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Auditory BCI Research Using Spoken Digits Stimulation and Dynamic Stopping Criterion
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作者 Ying Zhang Lei Wang +3 位作者 Miaomiao Guo Lei Qu Huanhuan Cui Shuo Yang 《Journal of Biomedical Science and Engineering》 2016年第10期71-77,共8页
Auditory brain-computer interfaces (BCI) provide a method of non-muscular commu-nication and control for late-stage amyotrophic lateral sclerosis (ALS) patients, who have impaired eye movements or compromised vision. ... Auditory brain-computer interfaces (BCI) provide a method of non-muscular commu-nication and control for late-stage amyotrophic lateral sclerosis (ALS) patients, who have impaired eye movements or compromised vision. In this study, random sequences of spoken digits were presented as auditory stimulation. According the protocol, the subject should pay attention to target digits and ignore non-target digits. EEG data were recorded and the components of P300 and N200 were extracted as features for pattern recognition. Fisher classifier was designed and provided likelihood estimates for the Dynamic Stopping Criterion (DSC). Dynamic data collection was controlled by a threshold of the posterior probabilities which were continually updated with each additional measurement. In addition, the experiment would be stopped and the decision was made once the probabilities were above the threshold. The results showed that this paradigm could effectively evoke the characteristic EEG, and the DSC algorithm could improve the accuracy and communication rate. 展开更多
关键词 Brain-Computer Interface P300 N200 dynamic Stopping criterion
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DYNAMIC TRAVERSAL CRITERION FOR GEOMETRIC FRACTALS
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作者 Zhang Qian Lu Zhenrong Xiao Zhonghui 《Computer Aided Drafting,Design and Manufacturing》 1996年第1期25-31,共2页
This paper presents a new generating criterion for self-similar geometric fractalsDynamic Traversal Criterion (DTC) and the principle to practice it. According to the principle,symbol shifting technique is put forward... This paper presents a new generating criterion for self-similar geometric fractalsDynamic Traversal Criterion (DTC) and the principle to practice it. According to the principle,symbol shifting technique is put forward which can control the traversal symbols dynamically in recursive procession. The Dynamic Traversal Criterion inherits the mechanism for generating self-similar fractals from traditional way and creates more fractal images from one initiator and generator than Static traversal strategy. 展开更多
关键词 ss: geometric fractal SELF-SIMILAR dynamic traversal criterion symbol shifting
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A new three-dimensional Hoek-Brown strength criterion 被引量:10
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作者 Hua Jiang Yong-Li Xie 《Acta Mechanica Sinica》 SCIE EI CAS CSCD 2012年第2期393-406,共14页
The Hoek-Brown (HB) strength criterion has been widely applied to the estimation of strength of intact rock and rock mass, while evolving ever since. However, negligence of the effect of the intermediate principal s... The Hoek-Brown (HB) strength criterion has been widely applied to the estimation of strength of intact rock and rock mass, while evolving ever since. However, negligence of the effect of the intermediate principal stress still remains in the criterion's latest version. At the same time, several three-dimensional (3D) HB strength, which can takes into account the influence of the intermediate principal stress, have already been proposed, among which the 3D HB criterion proposed by Zhang and Zhu seems to be the most reasonable one. However, the Zhang 3D HB criterion may have problems with some stress path close to triaxial extension state because of the non-convexity characteristic of its failure surface. In this paper, a new 3D HB strength criterion is presented based on a generalized form of the HB criterion, which also considers the effect of the intermediate principal stress and inherits all the merits of the original version of the HB criterion. In addition, this new criterion can remedy to some extent the shortcomings observed in the Zhang 3D HB criterion. Polyaxial tests for five different rocks from pub- lished literatures are used for evaluating this new criterion and comparing it with the Zhang 3D HB criterion. The re- sults show that this new criterion may over-predict or under- predict the polyaxial strength of rocks but the errors are rela- tively small, and similar results are also found for the Zhang 3D HB criterion, which one is better depends on the type of the rock under estimation. 展开更多
关键词 hoek-brown criterion Rock strength Merid-ian plane Octahedral plane
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Limit analysis for the seismic stability of three-dimensional rock slopes using the generalized Hoek-Brown criterion 被引量:9
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作者 A.Karrech X.Dong +3 位作者 M.Elchalakani H.Basarir M.A.Shahin K.Regenauer-Lieb 《International Journal of Mining Science and Technology》 SCIE EI CAS CSCD 2022年第2期237-245,共9页
The parameters that influence slope stability and their criteria of failure are fairly understood but over-conservative design approaches are often preferred,which can result in excessive overburden removal that may j... The parameters that influence slope stability and their criteria of failure are fairly understood but over-conservative design approaches are often preferred,which can result in excessive overburden removal that may jeopardize profitability in the context of open pit mining.Numerical methods such as finite element and discrete element modelling are instrumental to identify specific zones of stability,but they remain approximate and do not pinpoint the critical factors that influence stability without extensive parametric studies.A large number of degrees of freedom and input parameters may make the outcome of numerical modelling insufficient compared to analytical solutions.Existing analytical approaches have not tackled the stability of slopes using non-linear plasticity criteria and threedimensional failure mechanisms.This paper bridges this gap by using the yield design theory and the Hoek-Brown criterion.Moreover,the proposed model includes the effect of seismic forces,which are not always taken into account in slope stability analyses.The results are presented in the form of rigorous mathematical expressions and stability charts involving the loading conditions and the rock mass properties emanating from the plasticity criterion. 展开更多
关键词 Three-dimensional slope Seismic stability Generalized hoek-brown criterion Open pit
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New Oscillation Criteria of Second-Order Nonlinear Delay Dynamic Equations on Time Scales 被引量:6
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作者 Quanxin Zhang Li Gao 《Applied Mathematics》 2014年第21期3474-3483,共10页
By using the generalized Riccati transformation and the integral averaging technique, the paper establishes some new oscillation criteria for the second-order nonlinear delay dynamic equations on time scales. The resu... By using the generalized Riccati transformation and the integral averaging technique, the paper establishes some new oscillation criteria for the second-order nonlinear delay dynamic equations on time scales. The results in this paper unify the oscillation of the second-order nonlinear delay differential equation and the second-order nonlinear delay difference equation on time scales. The Theorems in this paper are new even in the continuous and the discrete cases. 展开更多
关键词 OSCILLATION criterion dynamic EQUATIONS Time SCALE
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Unified strength model based on the Hoek-Brown failure criterion for fibre-reinforced polymer-confined pre-damaged concrete columns with circular and square cross sections 被引量:6
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作者 ZHANG Yang LU Zhi-fang CAO Yu-gui 《Journal of Central South University》 SCIE EI CAS CSCD 2020年第12期3807-3820,共14页
Fibre-reinforced polymer(FRP)has the advantages of high strength,light weight,corrosion resistance and convenient construction and is widely used in repairing and strengthening damaged concrete columns.Most of the exi... Fibre-reinforced polymer(FRP)has the advantages of high strength,light weight,corrosion resistance and convenient construction and is widely used in repairing and strengthening damaged concrete columns.Most of the existing strength models were built by regression analysis of experimental data;however,in this article,a new unified strength model is proposed using the Hoek-Brown failure criterion.To study the strength of FRP-confined damaged and undamaged concrete columns,900 test data were collected from the published literature and a large database that contains the cross-sectional shape of each specimen,the damage type,the damage level and the FRP-confined stiffness was established.A new strength model using the Hoek-Brown failure criterion was established and is suitable for both circular and square columns that are undamaged,load-damaged and fire-damaged.Based on the database,most of the existing strength models from the published literature and the model proposed in this paper were evaluated.The evaluation shows that the proposed model can predict the compressive strength for FRP-confined pre-damaged and undamaged concrete columns with good accuracy. 展开更多
关键词 FRP-confined concrete load-damaged fire-damaged unified strength model hoek-brown failure criterion
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A simplified three-dimensional extension of Hoek-Brown strength criterion 被引量:7
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作者 Hangzhou Li Tong Guo +1 位作者 Yalin Nan Bo Han 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2021年第3期568-578,共11页
The Hoek-Brown(HB)strength criterion has been applied widely in a large number of projects around the world.However,this criterion ignores the intermediate principal stress s2.Many evidences have demonstrated that the... The Hoek-Brown(HB)strength criterion has been applied widely in a large number of projects around the world.However,this criterion ignores the intermediate principal stress s2.Many evidences have demonstrated that the rock strength is dependent on s2.Thus it is necessary to extend the HB criterion into a three-dimensional(3D)form.In this study,the effect of s2 on the strength of rocks is identified by reviewing the true triaxial tests of various rock types reported in the literature.A simple 3D strength criterion is developed.The modified criterion is verified by the true triaxial tests of 13 rock types.The results indicate that the modified criterion can achieve a good fit to most of rock types.It can represent a series of criteria as b varies.For comparisons,several existing 3D versions of the HB criterion are selected to predict the strengths of these rock types.It is indicated that the proposed criterion works better than other criteria.A substantial relationship between parameter b and the unconfined compressive strength is established,which guarantees that the proposed criterion can still work well even in the absence of true triaxial test data. 展开更多
关键词 hoek-brown(HB)strength criterion Three-dimensional(3D)strength criterion Intermediate principal stress Failure envelope
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Dynamic failure of dry and fully saturated limestone samples based on incubation time concept 被引量:6
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作者 Yuri V. Petrov Ivan V. Smirnov +3 位作者 Grigory A. Volkov Andrei K. Abramian Anatoliy M. Bragov Stanislav N. Verichev 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2017年第1期125-134,共10页
This paper outlines the results of experimental study of the dynamic rock failure based on the comparison of dry and saturated limestone samples obtained during the dynamic compression and split tests. The tests were ... This paper outlines the results of experimental study of the dynamic rock failure based on the comparison of dry and saturated limestone samples obtained during the dynamic compression and split tests. The tests were performed using the Kolsky method and its modifications for dynamic splitting. The mechanical data(e.g. strength, time and energy characteristics) of this material at high strain rates are obtained. It is shown that these characteristics are sensitive to the strain rate. A unified interpretation of these rate effects, based on the structuraletemporal approach, is hereby presented. It is demonstrated that the temporal dependence of the dynamic compressive and split tensile strengths of dry and saturated limestone samples can be predicted by the incubation time criterion. Previously discovered possibilities to optimize(minimize) the energy input for the failure process is discussed in connection with industrial rock failure processes. It is shown that the optimal energy input value associated with critical load, which is required to initialize failure in the rock media, strongly depends on the incubation time and the impact duration. The optimal load shapes, which minimize the momentum for a single failure impact, are demonstrated. Through this investigation, a possible approach to reduce the specific energy required for rock cutting by means of high-frequency vibrations is also discussed. 展开更多
关键词 dynamic strength Incubation time criterion Split Hopkinson pressure bar(SHPB) test Tensile strength Compressive strength Water-saturated limestone Vibration-assisted rock cutting
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Dynamic mechanical properties and instability behavior of layered backfill under intermediate strain rates 被引量:20
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作者 Yun-hai ZHANG Xin-min WANG +1 位作者 Chong WEI Qin-li ZHANG 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2017年第7期1608-1617,共10页
To obtain dynamic mechanical properties and failure rule of layered backfill under strain rates from10to80s-1,impactloading test on layered backfill specimens(LBS)was conducted by using split Hopkinson pressure bar sy... To obtain dynamic mechanical properties and failure rule of layered backfill under strain rates from10to80s-1,impactloading test on layered backfill specimens(LBS)was conducted by using split Hopkinson pressure bar system.The results indicatethat positive correlation can be found between dynamic compressive strength and strain rate,as well as between strength increasefactor and strain rate.Dynamic compressive strength of LBS gets higher as the arithmetic average cement-sand ratio increases.Compared with static compressive strength,dynamic compressive strength of LBS is enhanced by11%to163%.In addition,theenergy dissipating rate of LBS lies between that of corresponding single specimens,and it decreases as the average cement contentincreases.Deformation of LBS shows obvious discontinuity,deformation degree of lower strength part of LBS is generally higherthan that of higher strength part.A revised brittle fracture criterion based on the Stenerding-Lehnigk criterion is applied to analyzingthe fracture status of LBS,and the average relevant errors of the3groups between the test results and calculation results are4.80%,3.89%and4.66%,respectively. 展开更多
关键词 layered backfill specimen (LBS) split Hopkinson pressure bar (SHPB) dynamic mechanical properties damage characteristic failure criterion
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Elasto-plastic Analysis of Circular Tunnels in Jointed Rock Masses Satisfy the Hoek-Brown Failure Criterion 被引量:11
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作者 SUN Jin-shan LU Wen-bo ZHU Qi-hu CHEN Ming 《Journal of China University of Mining and Technology》 EI 2007年第3期393-398,共6页
The relationship between the Hoek-Brown parameters and the mechanical response of circular tunnels is il-lustrated. Closed-form and approximate solutions are given for the extent of the plastic zone and the stress and... The relationship between the Hoek-Brown parameters and the mechanical response of circular tunnels is il-lustrated. Closed-form and approximate solutions are given for the extent of the plastic zone and the stress and dis-placement fields under axisymmetrical and asymmetric stress conditions. For the same rock masses and under axisym-metrical stress conditions,the radius of the plastic zone in terms of Hoek-Brown criterion is generally an approximation of the radius in terms of the Mohr-Coulomb criterion. The radius in terms of the Hoek-Brown criterion is larger under low stress conditions. For poor quality rock masses (GSI<25),measures (such as grouting,setting rock bolts,etc.) that improve the GSI of rock masses are effective in improving the stability of tunnels. It is not advisable to improve the sta-bility of the tunnels by providing a small support resistance p through shotcrete,except for very poor quality jointed rock masses. Without reference to the quality of the rock mass,the disturbance factor D should not less than 0.5. Meas-ures which disturb rock masses during tunnel construction should be taken carefully when the tunnel depth increases. 展开更多
关键词 jointed rock masses circular tunnel general hoek-brown failure criterion elasto-plastic analysis con-struction measures
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A modified Hoek-Brown failure criterion considering the damage to reservoir bank slope rocks under water saturation-dehydration circulation 被引量:4
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作者 WANG Xin-gang WANG Jia-ding +1 位作者 GU Tian-Feng LIAN Bao-qin 《Journal of Mountain Science》 SCIE CSCD 2017年第4期771-781,共11页
After water is impounded in a reservoir, rock mass in the hydro-fluctuation belt of the reservoir bank slope is subject to water saturation- dehydration circulation (WSDC). To quantify the rate of change of rock mec... After water is impounded in a reservoir, rock mass in the hydro-fluctuation belt of the reservoir bank slope is subject to water saturation- dehydration circulation (WSDC). To quantify the rate of change of rock mechanical properties, samples from the Longtan dam area were measured with uniaxial compression tests after different numbers (1, 5, 10, 15, and 20) of simulated WSDC cycles. Based on the curves derived from these tests, a modified Hock- Brown failure criterion was proposed, in which a new parameter was introduced to model the cumulative damage to rocks after WSDC. A case of an engineering application was analyzed, and the results showed that the modified Hock-Brown failure criterion is useful. Under similar WSDC-influenced engineering and geological conditions, rock mass strength parameters required for analysis and evaluation of rock slope stability can be estimated according to this modified Hoek-Brown failure criterion. 展开更多
关键词 Modified hoek-brown criterion Reservoir bank slope Hydro-fluctuation belt Water saturation-dehydration circulation DAMAGE
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