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Search Results: 1 - 10 of 126952 matches for " LI Xibing "
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STATISTICAL PROBABILITY METHOD FOR THE EXTENSION OF A DISCONTINUOUS SURFACE IN ROCK MASS AND ITS APPLICATIONS
岩体弱面延展性的概率估算及其应用

Liu Aihua,Li Xibing,
刘爱华
,李夕兵

岩石力学与工程学报 , 1997,
Abstract: 岩体材料常被各类构造弱面所切割分离,这些弱面的特性严重影响甚至控制着岩体材料的力学及水力学性能。正确地对岩体中各类弱面的空间分布进行描述,对研究不同结构岩体的破坏机制,以及对合理地处理和解决岩体工程中的实际问题都具有重要意义。文章重点介绍了描述弱面的重要参数之一的弱面延展性的概率估算方法及其应用。
A DISTANCE DISCRIMINANT ANALYSIS METHOD FOR PREDICTION OF POSSIBILITY AND CLASSIFICATION OF ROCKBURST AND ITS APPLICATION
岩爆发生和烈度分级预测的距离判别方法及应用

GONG Fengqiang,LI Xibing,
宫凤强
,李夕兵

岩石力学与工程学报 , 2007,
Abstract: 岩爆是深部高地应力区岩石地下工程中的主要工程地质灾害之一,对其发生的可能性及其烈度分级的预测是工程建设过程中所必须解决的重大问题。基于距离判别分析理论,建立岩爆发生和烈度分级预测的距离判别分析模型。选取影响岩爆的主要因素如最大切向应力σθ、小单轴抗压强度σc、单轴抗拉强度σt和弹性能量指数Wet,并把σθ/σc,σc/σt和Wet作为判别因子建立岩爆预测的距离判别分析模型,利用国内外一些重大深部岩石工程实例作为学习的样本进行训练。经过训练后的模型回判估计的误判率为0。利用该模型对国内西康铁路秦岭隧道工程和铜陵冬瓜山深埋硬岩矿山的岩爆情况进行预测,结果与实际情况符合较好,说明该模型在研究岩爆发生可能性及烈度分级预测中具有良好的实用性和有效性。该方法可为深部地下工程岩爆发生可能性及其烈度分级预测提供一种新思路。
CONSTITUTIVE MODEL OF ROCK UNDER COUPLED STATIC-DYNAMIC LOADING WITH INTERMEDIATE STRAIN RATE
中应变率下动静组合加载岩石的本构模型

LI Xibing,ZUO Yujun,MA Chunde,
李夕兵
,左宇军,马春德

岩石力学与工程学报 , 2006,
Abstract: The importance of study on constitutive model of statically loaded rock under dynamic loading is expounded,and the methods of dynamic constitutive model are classified according to the current studying.By way of combining statistic damage model and viscoelastic model,uniaxial and triaxial constitutive models of statically loaded rock under dynamic loading(coupled static-dynamic constitutive model) with intermediate strain rate are established.The verification experiment on 1D coupled static-dynamic constitutive model under different static loadings is designed and performed.It is found that there is a good agreement between experimental stress-strain curves and theoretical stress-strain curves.The 3D theoretical stress-strain curves under different strain rates are verified by test data.
ANALYTICAL ALGORITHM TO ESTIMATE TENSILE MODULUS IN BRAZILIAN DISK SPLITTING TESTS
巴西圆盘劈裂试验中拉伸模量的解析算法

GONG Fengqiang,LI Xibing,ZHAO J,
宫凤强
,李夕兵,ZHAO J

岩石力学与工程学报 , 2010,
Abstract: 提出巴西圆盘劈裂试验中拉伸模量的解析算法。结合圆盘对心受力的理论弹性解和实际试验过程中便于测量的物理参数,基于微积分的原理,通过对试样中心垂直加载方向上每一点拉应变的积分,可以得到该方向上总的变形量,进而推导出岩石拉伸模量和总位移变形量之间的定量关系式。该关系式包含加载力、试样直径、试样厚度、岩石泊松比和试样中心垂直加载方向上总位移变形量5个物理量,其意义明确,运用简便,可为求解巴西劈裂试验拉伸模量提供一种新的方法。
EFFECTS OF SINGLE JOINT WITH NONLINEAR NORMAL DEFORMATION ON P-WAVE PROPAGATION
非线性法向变形节理对弹性纵波传播的影响

WANG Weihua,LI Xibing,ZUO Yujun,
王卫华
,李夕兵,左宇军

岩石力学与工程学报 , 2006,
Abstract: The linear displacement discontinuity model is derived from elastic displacement functions of wave, and then a nonlinear displacement discontinuity model is established by introducing the equivalent displacement hypothesis. Based on the established model, the analytic resolution of transmitted and reflected coefficients is obtained when the normal incident P-wave propagates to the nonlinear normal deformative joint. The effects of parameters such as initial joint stiffness, quantitative ratio of joint closure to allowable joint closure and incident frequency of wave on transmitted and reflected coefficients are investigated. By comparison with the published numerical results, it is found that the analytic results agree well with the numerical calculations.
APPLICATION OF DISTANCE DISCRIMINANT ANALYSIS METHOD TO CLASSIFICATION OF ENGINEERING QUALITY OF ROCK MASSES
距离判别分析法在岩体质量等级分类中的应用

GONG Fengqiang,LI Xibing,
宫凤强
,李夕兵

岩石力学与工程学报 , 2007,
Abstract: Based on the principle of Mahalanobis distance discriminant analysis,a classification model of engineering quality of rock masses is established,including six indexes reflecting the engineering quality of rock masses:uniaxial compressive strength,P-wave velocity in rock,volumetric joint countr,oughness coefficients of joints,weathering coefficients and permeability coefficient of joints.Linear discriminant functions are obtained through training a large set of expansive samples.The results show that the classification model of distance discriminant analysis has excellent performance,high prediction accuracy;and can be used in practical engineering.
CONSTITUTIVE MODEL OF ROCK JOINTS UNDER COMPRESSION LOADS WITH DIFFERENT FREQUENCIES
不同频率载荷作用下的岩石节理本构模型

LI Xibing,WANG Weihua,MA Chunde,
李夕兵
,王卫华,马春德

岩石力学与工程学报 , 2007,
Abstract: Dynamic compression tests of different loading frequencies on artificial joints with different saw-teeth are performed by Instron1342 servo-controlled material testing machine.Based on the analysis of test results,the effect of both the surface topography and loading frequency on the joint closure behavior is discussed.By comparison of the fitting potential of five empirical functions with the closure curves of rock joints under normal loads with different frequencies,it is suggested that the power function is very suitable for expressing the dynamic closure behavior of the joints.By analyzing the quantitative relations between the fitting parameters of power function and strain rates,a new dynamic constitutive model of rock joints is proposed.The test results show that the established model gives reasonable estimations of the deformation behavior of joints under dynamic loads.
RELIABILITY ANALYSIS ON PILLAR STRUCTURE USING A NEW MONTE-CARLO FINITE ELEMENT METHOD
用改进的有限元Monte-Carlo法分析金属矿山点柱的可靠性

Deng Jian,Li Xibing,Gu Desheng,
邓建
,李夕兵,古德生

岩石力学与工程学报 , 2002,
Abstract: Non-pillar continuous mining(NPCM) is briefly introduced in an underground metal mine as an example of a new continuous mining method. The pillar of excavation room plays a critical role in the stability status of NPCM. Therefore,probabilistic method (reliability analysis method) is adopted to deal with the uncertainties in rock mass and ore body. By calculating the strength analytically and stress numerically of the pillar,the implicit limit state equation is established,which is different from general limit state equation. To carry out the reliability analysis of pillar,a new Monte-Carlo finite element method based on neural network is needed and presented. Reliability index is obtained to evaluate the pillars performance. The results are proved to be correct by the mining engineers,and the new method is of good application effect and prospect.
THE RELATIONSHIP BETWEEN THE ELECTROMAGNETIC RADIATION(EMR) AND ROCKMASSES PARAMETERS DURING ROCK FAILURE
岩石破裂电磁辐射幅值与岩石属性参数的关系

WAN Guoxiang,LI Xibing,
万国香
,李夕兵

力学与实践 , 2008,
Abstract: Based on the hypothesis of the EMR created by atom perturbation resulting from propagating cracks during rock fracture, the crack length and area are calculated through fracture mechanics under small yield condition. The expression of the EMR amplitude and rock's attribute parameters is presented according to the relation between EMR amplitude and crack length and area. The dependence of the EMR amplitude on each attribute parameter is discussed. The obtained results show that the EMR amplitude increases with the elastic modulus and the influence of rock dimension on the EMR is greater than its lithology. The results of this paper are in good agreement with many experimental measurements.
A Comparison of the Analgesia Efficacy and Side Effects of Paravertebral Compared with Epidural Blockade for Thoracotomy: An Updated Meta-Analysis
Xibing Ding, Shuqing Jin, Xiaoyin Niu, Hao Ren, Shukun Fu, Quan Li
PLOS ONE , 2014, DOI: 10.1371/journal.pone.0096233
Abstract: Objective The most recent systematic review and meta-analysis comparing the analgesic efficacy and side effects of paravertebral and epidural blockade for thoracotomy was published in 2006. Nine well-designed randomized trials with controversial results have been published since then. The present report constitutes an updated meta-analysis of this issue. Summary of Background Thoracotomy is a major surgical procedure and is associated with severe postoperative pain. Epidural analgesia is the gold standard for post-thoracotomy pain management, but has its limitations and contraindications, and paravertebral blockade is increasingly popular. However, it has not been decided whether the analgesic effect of the two methods is comparable, or whether paravertebral blockade leads to a lower incidence of adverse side effects after thoracotomy. Methods Two reviewers independently searched the databases PubMed, EMBASE, and the Cochrane Library (last performed on 1 February, 2013) for reports of studies comparing post-thoracotomy epidural analgesia and paravertebral blockade. The same individuals independently extracted data from the appropriate studies. Result Eighteen trials involving 777 patients were included in the current analysis. There was no significant difference in pain scores between paravertebral blockade and epidural analgesia at 4–8, 24, 48 hours, and the rates of pulmonary complications and morphine usage during the first 24 hours were also similar. However, paravertebral blockade was better than epidural analgesia in reducing the incidence of urinary retention (p<0.0001), nausea and vomiting (p = 0.01), hypotension (p<0.00001), and rates of failed block were lower in the paravertebral blockade group (p = 0.01). Conclusions This meta-analysis showed that PVB can provide comparable pain relief to traditional EPI, and may have a better side-effect profile for pain relief after thoracic surgery. Further high-powered randomized trials are to need to determine whether PVB truly offers any advantages over EPI.
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