Mechanism on progressive failure of a faulted rock slope due to slip-weakening

1 Introduction The damage or failure of faulted rock slope is a quite difficult problem in geotechni- cal engineering, and attention has been drawn from researchers for a long time. Apart from the toppling damage of steep slopes, most of the failure pattern of faulted rockslopes is shear-typed. The failure process of such a slope includes: initiation and devel- opment of a single micro-crack, breakthrough of two or more cracks, formation of fail- ure zones, and even shear damage in large scale…     

顺倾向层状岩质边坡溃屈破坏分析

为了解顺倾向层状岩质边坡的溃屈破坏特性,根据多层层状岩质边坡的溃屈破坏模式,并考虑静水压力和地震的影响,建立了相应的力学模型.采用特殊函数理论进行分析,得出各层岩体溃屈曲线的理论公式,对此类边坡溃屈破坏的临界坡长和破坏位置进行了求解.分析了岩石弹性模量、层间滑动面强度、岩层厚度、层面倾角等因素对此类边坡溃屈破坏临界坡长的影响.针对工程实例的分析结果与实际情况符合较好,证明了该理论的正确性.     

崩塌堆积体的渐性破坏及稳定性分析

崩塌堆积体是我国西南高山峡谷区常见的不良地质体,该类边坡的失稳破坏呈现渐进性破坏特征,由于传统的边坡稳定性计算的条分法无法反映它的破坏过程和机理,也无法确定其长期稳定性,因此,分析崩塌堆积体稳定性影响因素的基础上,采用FLAC内嵌fish程序语言对崩塌堆积体边坡的渐进性破坏过程进行仿真模拟分析,其中,数值模拟时考虑了崩塌堆积体边坡物料抗剪强度的非线性等堆积特点对其稳定性的影响.通过FLAC数值模拟仿真分析,清晰地揭示了崩塌堆积体边坡渐进破坏的演化过程,证实了崩塌堆积体边坡的稳定性随时间推移逐渐降低的趋势.     

高陡顺向岩质人工边坡治理研究

在工程地质评价基础上,应用数学力学模拟方法进行切坡稳定性定量评价.结合切坡特点,对深层结构面采用推力传递系数法进行稳定性计算,基本荷载仅考虑岩体自重,组合荷载包括重力、静水(渗水)压力和地震力的组合作用.该切坡是由破碎岩体的块状多次多向块体滑移与深层层面滑移结合的破坏模式.考虑局部滑移与整体滑动的危险,暴雨与风化作用下,边坡变形破坏可能进一步发育,提出预应力锚索+地梁的措施进行治理是合适的.     

岩质高边坡岩体力学参数确定及稳定性研究

以云南某露天矿采场岩质高边坡工程为研究对象,阐述了岩体力学参数在边坡稳定性分析中的重要性,因原位试验对于坚硬岩体或极软岩体的不适用性,对坚硬岩体,以室内试验得出的岩石物理力学参数和岩体质量评价RMR评分值为依据,并综合考虑岩体中节理裂隙、岩体结构、地下水的影响,运用霍克-布朗(Hoek-Brown)强度准则将岩石力学参数进行折减修正后换算成岩体力学参数,并与现场原位试验所得软弱岩体力学参数结果相结合得到最终岩体力学参数.在上述调查、研究基础上,采用有限差分法(FLAC数值分析软件)对现状边坡进行静态的稳定性分析,提出合理的最终边坡角及总台阶高度,保证矿山正常生产和经济效益的提高.     

裂隙及卸荷对岩体边坡的影响

应用弹塑性力学及断裂力学的相关理论,分析讨论了裂纹的分形特性及裂隙面的压剪起裂破坏机理;分析了静载、动载和不同类型裂隙的相互作用对边坡稳定性的影响规律。结合工程实际问题,研究了边坡开挖前后其应力应变的分布规律,提出了由于开挖卸荷而引起裂纹扩展的作用机理。     

岩质边坡稳定性分析方法研究

岩质边坡稳定性研究是一个具有重大现实意义的课题,一直是岩土工程的一个重要研究内容.近年来,随着工程建设数量的增加和规模的加大,岩质边坡失稳破坏的灾害频繁发生,造成的损失也逐年增加.因此,对岩质边坡稳定性进行研究显得越来越重要.介绍了边坡稳定性分析的各种方法,并且简要阐述了各种分析方法的特点,最后对边坡稳定性分析方法的发展趋势作了简要的论述.     

裂隙及卸荷对岩体边坡的影响

应用弹塑性力学及断裂力学的相关理论,分析讨论了裂纹的分形特性及裂隙面的压剪起裂破坏机理;分析了静载、动载和不同类型裂隙的相互作用对边坡稳定性的影响规律.结合工程实际问题,研究了边坡开挖前后其应力应变的分布规律,提出了由于开挖卸荷而引起裂纹扩展的作用机理.     

岩质边坡在降雨条件下的稳定性分析

雨水入渗改变了岩质边坡非饱和区渗流场的分布,是引发边坡滑坡的主要因素之一.在极限平衡理论和非饱和土抗剪强度理论基础上,引入了渗透力的概念,利用有限单元法进行了降雨条件下岩质边坡稳定性的分析.最后,利用编制的边坡稳定程序进行了算例分析,结果表明,岩体边坡的稳定安全系数随着雨水的不断渗入在逐渐地降低,即降雨入渗对边坡的稳定具有不利影响.     

Practical assessment of rock damage due to blasting

Blasting is the most cost effective methodology to break rock for mining or civil engineering applications.A good production blast will break only the rock that is needed to be removed, leaving the host rock with minimal damage. The control of rock damage due to blasting is very important when it comes to mine or construction design, safety, and cost. Damage to the host rock due to a production blast could result in failures, overbreak and unstable ground. Knowing how far the fractures generated by a production blast will go into the host rock is a valuable tool for engineers to design a safe highwall while keeping the actual excavation close to the design. Currently, there are several methods available to predict damage due to blasting. The accuracy of many of these methods is questionable, and in most cases, the methodologies over predict the results. This often leads to inefficient mines and poor construction works. When the current methodologies are reviewed, each one presents sound approaches, but in many cases they also lack consideration of other variables that, according to the authors, need to be included when predicting blast damage. This paper presents a practical methodology to assess the rock damage from blasting by combining other methodologies. The proposed method allows consideration of more variables when compared to available methods, resulting in a more accurate rock damage assessment. The method uses the estimation of the generated levels of peak particle velocity with the distance from a production blast presented by Persson and Holmberg, the peak particle velocity damage ranges proposed by Forsyth and the relationship between the static compressive strength and dynamic compressive strength of rocks from Liu. The new methodology was validated using the data published in a large-scale study performed in granite by Siskind.     

岩质高边坡治理初探

岩质高边坡，因其缺乏生物赖以生存的环境，既使经过传统的加固措施，却因暴露于地表，受到风吹、日晒、雨淋等各种破坏性侵蚀作用，表层岩石很容易降低强度，发生剥蚀脱落，降低边坡稳定性，危及工程的安全性．针对岩质高边坡的特点，探讨了岩质高边坡的治理措施，介绍了一些新的边坡治理技术．高边坡治理既要注重稳定性，还要考虑生态环境问题，景观设计应成为边坡治理中的一部分．     

Numerical study on rock fracture and vibration due to blasting

Fracture and ground vibration of rock subjected to different decoupling decked charges are investigated based on the numerical simulation.The dynamic pressure value is studied,which demonstrates that simulation of fracture zone is feasible.Attenuation index of dynamic pressure is 2.06,2.05 and 1.93 for air,water and sand intervals respectively.The small attenuation of sand interval results in the large ground vibration.The predicted vertical vibration waveform and peak particle velocities(PPV) in far-field are in agreement with the monitoring results.The results show that the air and water decked charges can improve the effect of rock fracture in near-field and reduce ground vibration in far-field.     

岩质边坡楔形体破坏的稳定性分析

为了更准确地判断岩质边坡发生楔形体破坏时的稳定性,利用极限平衡原理,分析楔形体受力的平衡条件,推导得出了楔形四面体的安全系数.通过对典型边坡计算分析,得出边坡稳定系数.该方法适用性强,计算简单,结果与工程实际相符,可以在工程实践中推广应用.     

Influence of blasting on the properties of weak intercalation of a layered rock slope

A precondition for correctly analyzing the stability of a slope and designing its bracing structure is to study and determine the influence of excavation blasting on the properties of weak intercalation in the layered rock slope.On the basis ofin-situ stratifica-tion-cracking blasting tests,the properties of weak intercalation were investigated using the LS-DYNA3D program.The displace-ment distribution and compactness of weak intercalation at different positions away from the charge center and their various laws are discussed.The critical displacement of stratification-cracking (0.1 mm) was obtained,and an approximate expression of compactness were deduced.Furthermore,through the simulation of a layered rock blasting under the same geological conditions,the stratifica-tion-cracking effect of deep-hole blasting on the properties of weak intercalation was compared with that of short-hole blasting,and the influencing differences,in addition to their causes,were analyzed.The results indicated that the blasting cavity of weak intercala-tion in short-hole blasting with a radius of 40 mm was nearly a circle,whose radius was about 28.7 cm;whereas in deep-hole blasting with a radius of 150 mm,the shape of the blasting cavity was different from that in short-hole blasting,the radius of the cavity be-hind the charge (89.1 cm) was further smaller than those of the other three (138.7 cm),and there were sharp crinkles on the surface of weak intercalation.When the distance from the charge center (DCC) was less than 40 and 150 cm in short-hole and deep-hole blast-ing,respectively,the displacement of weak intercalation was reduced remarkably with the increase in DCC.     

边坡工程中卸荷岩体的探讨

岩体卸荷是水利水电工程建设中常见的工程地质问题,岩体卸荷裂隙是影响边坡岩体稳定性的重要因素.文章介绍了边坡工程中卸荷岩体的形成机理、裂隙类型、分带依据及卸荷岩体加固时应注意的问题.     

急倾斜多煤层开采地表沉陷分区与围岩破坏机理——以木城涧煤矿大台井为例

为了研究急倾斜多煤层开采条件下地表及围岩移动变形特点,以木城涧煤矿大台井急倾斜多煤层开采为研究对象,进行了相似材料模拟研究.揭示了地表移动变形规律和围岩垮落、破坏机理,得出了不同区域移动变形的大小及主要特点,并与实地观测数据进行了对比分析.结果表明:该条件下开采,地表沉陷盆地可分为露头塌陷区、整体沉陷区、渐变沉陷区和轻微沉陷区,浅部开采形成的地表分区格局对整个采动影响区的地表移动变形起到了控制作用,浅部开采覆岩破坏以陷落和张裂为主要特征,深部开采以离层带裂隙顺层通达地表和台阶错落下沉为主要特征.     

流固耦合作用下节理岩质边坡失稳过程的RFPA模拟分析

利用基于强度折减法的RFPA-Slope对渗流与应力耦合作用下的软弱互层岩质边坡稳定性进行了数值模拟分析,数值模拟不但直观形象地给出了边坡的渗流场、应力场、破坏区分布,而且得到了边坡滑移破坏面的萌生、扩展、贯通以及坡体整体失稳的渐进破坏过程,同时求得安全系数。并与无地下水的稳定性作了比较,结果表明,地下水渗流的作用使坡体位移增大,边坡安全系数减小,明显加大了滑坡范围。对实例的分析说明,RFPA-Slope能够较为准确地预测边坡潜在破坏面的形状与位置及计算相应的稳定安全系数,本文方法对于边坡,特别是对于复杂边坡的稳定性分析具有实用性。     

确定岩质边坡地震安全系数的新方法

地震作用下岩质边坡安全系数是一个随时间变化的函数,如何依据岩质边坡安全系数时程给出边坡在地震作用下的稳定性评价指标,这是一个尚未很好解决的工程难题.基于显式波动有限元方法,给出了岩质边坡动力安全系数时程的计算方法,并引入可靠度的概念,提出了新的边坡动力稳定性评价指标-可靠度动力安全系数,给出了相应的计算方法,即边坡的可靠度动力安全系数等于边坡安全系数时程的平均值减去边坡安全系数时程的标准差与工程可接受的可靠度的乘积,使边坡的动力稳定性评价与工程可接受的风险紧密结合起来.将其应用于某岩质边坡,并与拟静力法的结果进行了比较.结果表明,所提出的边坡动力稳定性评价指标能够较好地考虑工程风险,其计算方法是可靠的,可直接应用实际工程.     

含硬性贯通结构面的岩质边坡稳定性研究

选取典型的具有硬性贯通结构面的岩质边坡模型,采用有限元强度折减法并应用岩土数值模拟软件对其进行详细的数值模拟,得到边坡在不同位置结构面、坡角及倾角下的安全系数和潜在滑移面。这说明将含贯通结构面的岩体总体特征予以反映并使之模型化是可行的。结果表明,随着结构面与坡脚距离的增大,安全系数也逐渐提高;边坡坡度越大,剪应力向坡脚集中,继而易发生破坏;坡角一定时,安全系数随倾角呈U形抛物线变化;潜在滑移面不一定沿着结构面发生破坏,也可能在岩体内滑动。上述各项岩土参数对岩质边坡稳定性的影响规律,可用于指导工程实践,有一定的推广价值。     

基极注入HPM导致的双极型晶体管失效分析简

In order to determine the influence of HPM on BJT, the physical process and model are proposed based on the experimental phenomena of BJT injecting HPM from the base. Simulation results by using the model and process proposed in the paper show that the main mechanism of failure and degradation of BJT caused by HPM is that the induced voltage pulse generated by HPM leads to the burn-up and the formation of the fuse element and defect in the base. The burnt area and the number of defects which vary with the power and time of HPM on the devices cause the device failure and the change of DC characteristics.The simulation result is in good agreement with the phenomena of the BJT HPM effect experiment, which indicates that the analysis in this paper is correct.