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An empirical approach for predicting burden velocities in rock blasting

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Journal of Rock Mechanics and Geotechnical Engineering 2021年第4期13卷 767-773页

作者： zong-xian zhang Li-Yuan Chi Changping Yi Oulu Mining School University of OuluOuluFI-90014Finland State Key Laboratory of Explosion Science and Technology Beijing Institute of TechnologyBeijingChina Division of Mining and Geotechnical Engineering Lulea University of TechnologyLuleaSweden

An analytical relation between burden velocity and ratio of burden to blasthole diameter is developed in this *** relation is found to be consistent with the measured burden velocities of all 37 full-scale blasts found from published *** blasts include single-hole blasts,multi-hole blasts,and simultaneously-initiated blasts with various borehole diameters such as 64 mm,76 mm,92 mm,115 mm,142 mm and 310 *** boreholes were fully *** agreement between measured and calculated burden velocities demonstrates that this relation can be used to predict the burden velocity of a wide range of full-scale blast with fully-coupled explosive charge and help to determine a correct delay time between adjacent holes or rows in various full-scale blasts involved in tunnelling(or drifting),surface and underground mining production blasts and underground opening slot *** addition,this theoretical relation is found to agree with the measured burden velocities of 9 laboratory small-scale blasts to a certain *** predict the burden velocity of a small-scale blast,a further study or modification to the relation is necessary by using more small-scale blasts in the future.

关键词： Burden velocity Rock blasting Kinetic energy Delay time Tunnelling Minin

Empirical equations between characteristic impedance and mechanical properties of rocks

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Journal of Rock Mechanics and Geotechnical Engineering 2020年第5期12卷 975-983页

作者： zong-xian zhang De-Feng Hou Adeyemi Aladejare Oulu Mining School University of OuluOulu90014Finland College of Resources and Safety Engineering China University of Mining and TechnologyBeijing100083China

Based on a great number of experimental data on various mechanical properties of rock in the literature,six empirical equations between the characteristic impedance(product of density and P-wave velocity)and mechanical properties of rock are *** properties include uniaxial compressive strength,tensile strength,shear strength,mode I fracture toughness,Young’s modulus,and Poisson’s *** empirical equations show that the values of the aforementioned properties increase with increase in characteristic *** also implies that the characteristic impedance of rock may be considered as an index to represent the main properties of *** this sense,it is possible to consider using characteristic impedance to classify rock masses for studies in the future.

关键词： Characteristic impedance Mechanical properties Rock mass Classification Strength

Predicting dynamic compressive strength of frozen-thawed rocks by characteristic impedance and data-driven methods

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第7期16卷 2591-2606页

作者： Shengtao Zhou zong-xian zhang Xuedong Luo Yifan Huang Zhi Yu Xiaowei Yang Faculty of Engineering China University of GeosciencesWuhan430074China Oulu Mining School University of OuluOulu90570Finland Zijin School of Geology and Mining Fuzhou UniversityFuzhou350116China Department of Earth Science&Engineering Imperial College LondonLondonSW72AZUK

In cold regions,the dynamic compressive strength(DCS)of rock damaged by freeze-thaw weathering significantly influences the stability of rock ***,testing the dynamic strength under freeze-thaw weathering conditions is often both time-consuming and ***,this study considers the effect of characteristic impedance on DCS and aims to quickly determine the DCS of frozen-thawed rocks through the application of machine-learning ***,a database of DCS for frozen-thawed rocks,comprising 216 rock specimens,was *** external load parameters(freeze-thaw cycle number,confining pressure,and impact pressure)and two rock parameters(characteristic impedance and porosity)were selected as input variables,with DCS as the predicted *** research optimized the kernel scale,penalty factor,and insensitive loss coefficient of the support vector regression(SVR)model using five swarm intelligent optimization algorithms,leading to the development of five hybrid *** addition,a statistical DCS prediction equation using multiple linear regression techniques was *** performance of the prediction models was comprehensively evaluated using two error indexes and two trend indexes.A sensitivity analysis based on the cosine amplitude method has also been *** results demonstrate that the proposed hybrid SVR-based models consistently provided accurate DCS *** these models,the SVR model optimized with the chameleon swarm algorithm exhibited the best performance,with metrics indicating its effectiveness,including root mean square error(RMSE)﹦3.9675,mean absolute error(MAE)﹦2.9673,coefficient of determination(R^(2))﹦0.98631,and variance accounted for(VAF)﹦*** suggests that the chameleon swarm algorithm yielded the most optimal results for enhancing SVR ***,impact pressure and characteristic impedance emerged as the two most influential parameters in DCS *** research is

关键词： Freeze-thaw cycle Characteristic impedance Dynamic compressive strength Machine learning Support vector regression

Sidewall rockburst of highly stressed D-shape hole tunnel triggered by impact load: An experimental investigation

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Rock Mechanics Bulletin

Rock Mechanics Bulletin 2024年第1期3卷 64-80页

作者： Wuxing Wu Fengqiang Gong zong-xian zhang School of Civil Engineering Southeast UniversityNanjing211189China Oulu Mining School University of OuluOulu90570Finland

This study aims to clarity the failure mechanism of sidewall rockburst of highly stressed D-shape tunnel triggered by impact *** the biaxial Hopkinson pressure bar(BHPB)system,we have developed experimental capabilities to study the sidewall rockburst of D-shape tunnel by applying various prestresses,including horizontal and vertical static stresses,to sand prefabricated D-shape hole specimen,followed by impact ***-speed(HS)camera and digital image correlation(DIC)were used to tracked the process and strain field of the sidewall *** test results reveal that the process of sidewall rockburst can be summarized as:calm stage,crack initiation,propagation,and coalesce stage,spalling stage and rock fragments ejection *** the rockburst process,the surrounding rock experienced spalling and violent ejection,involving both tensile and tensile-shear *** mechanism of sidewall rockburst under the coupled of static stress and impact loads has been elucidated,i.e.,the static prestress determines the initial stress and strain distribution,and the horizontal prestress influences the affected range and strain values of strain concentration zone;the impact load disrupts the original static stress equilibrium,inducing alterations in the stress and strain of the surrounding rock and triggering sidewall rockburst.

关键词： impact rock load

Prediction of uniaxial compressive strength of rock based on lithology using stacking models

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Rock Mechanics Bulletin

Rock Mechanics Bulletin 2023年第4期2卷 56-69页

作者： Zida Liu Diyuan Li Yongping Liu Bo Yang zong-xian zhang School of Resources and Safety Engineering Central South UniversityChangsha410083China Nickel Cobalt Research and Design Institute Jinchuan Group Co.Ltd.Jinchang737104China Oulu Mining School University of OuluOuluFinland

Uniaxial compressive strength(UCS)of rock is an essential parameter in geotechnical *** load strength(PLS),P-wave velocity,and Schmidt hammer rebound number(SH)are more easily obtained than UCS and are extensively applied for the indirect estimation of *** study collected 1080 datasets consisting of SH,P-wave velocity,PLS,and *** datasets were integrated into three categories(sedimentary,igneous,and metamorphic rocks)according to *** models combined with tree-based models and linear regression were developed based on the datasets of three rock *** evaluation showed that the stacking model combined with random forest and linear regression was the optimal model for three rock *** of metamorphic rocks was less predictable than that of sedimentary and igneous ***,the proposed stacking models can improve the predictive performance for UCS of metamorphic *** developed predictive models can be applied to quickly predict UCS at engineering sites,which benefits the rapid and intelligent classification of rock ***,the importance of SH,P-wave velocity,and PLS were analyzed for the estimation of *** was a reliable indicator for UCS evaluation across various rock types.P-wave velocity was a valid parameter for evaluating the UCS of igneous rocks,but it was not reliable for assessing the UCS of metamorphic rocks.

关键词： Uniaxial compressive strength Point load strength P-wave velocity Schmidt hammer rebound number Stacking models

Insights into spinal muscular atrophy from molecular biomarkers

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Neural Regeneration Research 2025年第7期20卷 1849-1863页

作者： Xiaodong Xing Xinzhu Liu xiandeng Li Mi Li xian Wu Xiaohui Huang Ajing Xu Yan Liu Jian zhang Department of Clinical Pharmacy Xinhua HospitalShanghai Jiao Tong University School of MedicineShanghaiChina College of Pharmacy Chongqing Medical UniversityChongqingChina

Spinal muscular atrophy is a devastating motor neuron disease characterized by severe cases of fatal muscle *** is one of the most common genetic causes of mortality among infants aged less than 2 *** research is currently receiving more attention,and new candidate biomarkers are constantly being *** review initially discusses the evaluation methods commonly used in clinical practice while briefly outlining their respective pros and *** also describe recent advancements in research and the clinical significance of molecular biomarkers for spinal muscular atrophy,which are classified as either specific or non-specific *** review provides new insights into the pathogenesis of spinal muscular atrophy,the mechanism of biomarkers in response to drug-modified therapies,the selection of biomarker candidates,and would promote the development of future ***,the successful utilization of biomarkers may facilitate the implementation of gene-targeting treatments for patients with spinal muscular atrophy.

关键词： biomarkers disease progression gene-targeting therapy neurofilaments Nusinersen spinal muscular atrophy(SMA) survival motor neuron therapeutic evaluation treatment outcomes

GPIO-Based Continuous Sliding Mode Control for Networked Control Systems Under Communication Delays With Experiments on Servo Motors

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IEEE/CAA Journal of Automatica Sinica 2025年第1期 99-113页

作者： Kamal Rsetam Zhenwei Cao Zhihong Man xian-Ming zhang the School of Software and Electrical Engineering Swinburne University of Technology the Department of Automated Manufacturing Al Khwarizmi College of Engineering University of Baghdad IEEE

To handle input and output time delays that commonly exist in many networked control systems(NCSs), a new robust continuous sliding mode control(CSMC) scheme is proposed for the output tracking in uncertain single input-single-output(SISO) networked control systems. This scheme consists of three consecutive steps. First, although the network-induced delay in those systems can be effectively handled by using Pade approximation(PA), the unmatched disturbance cames out as another difficulty in the control design. Second, to actively estimate this unmatched disturbance, a generalized proportional integral observer(GPIO) technique is utilized based on only one measured state. Third, by constructing a new sliding manifold with the aid of the estimated unmatched disturbance and states, a GPIO-based CSMC is synthesized, which is employed to cope with not only matched and unmatched disturbances, but also networkinduced delays. The stability of the entire closed-loop system under the proposed GPIO-based CSMC is detailedly *** promising tracking efficiency and feasibility of the proposed control methodology are verified through simulations and experiments on Quanser's servo module for motion control under various test conditions.

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石质丘陵山地水土流失时空变化初步研究

水土保持研究 2004年第2期11卷 24-26页

作者：方天纵张贤瑞刘秀芹天津市水利局农水处天津300074

根据蓟县白马泉小流域资料,对水土流失规律进行初步研究。降雨是该地区水土流失产生的主要动力成因之一,在同一降雨条件下,试验小区产流量的顺序为,荒坡>松树>梯田>紫穗槐;年降雨量与径流量呈线性相关关系;有效降雨量与径流量呈幂指数关... 详细信息

根据蓟县白马泉小流域资料,对水土流失规律进行初步研究。降雨是该地区水土流失产生的主要动力成因之一,在同一降雨条件下,试验小区产流量的顺序为,荒坡>松树>梯田>紫穗槐;年降雨量与径流量呈线性相关关系;有效降雨量与径流量呈幂指数关系;年降雨量与输沙量亦呈幂指数关系。

关键词：小流域降雨径流模拟方程

基于GIS的天津市水土流失监测信息系统建设

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水土保持研究 2004年第2期11卷 36-38,62页

作者：方天纵张贤瑞刘秀芹天津市水利局农水处天津300074

结合3S技术概念内涵及技术集成特点对水土流失监测与管理信息系统建设特点及一般要求进行论述。以天津市蓟县水土流失监测实践为例,对系统建设科学性与重要性进行叙述。

关键词： 3S技术水土流失监测系统