含偏置裂纹的三点弯曲梁破坏过程颗粒流模拟     

丁永政  邓清海  刘兆冰  李宏 《高校地质学报》1997,25(4):519

为研究三点弯曲梁在荷载作用下的破坏模式，采用颗粒流程序PFC2D对含不同位置和高度的预置裂隙的三点弯曲 梁破坏过程进行了模拟。结果表明：预制裂隙的长度与位置共同影响梁的破坏；当预置裂隙的位置离加载点较远时，主 要是预置裂隙的高度对梁的破坏产生影响，当裂隙高度超过70 mm时，试件的破坏模式发生变化；当预置裂隙高度一定 时，预置裂隙的位置是试件发生破坏的主要影响因素，当距离支撑点的距离超过100 mm时，试件的破坏模式发生了改 变；试件的破坏过程伴随着能量的积累和释放。相比较于有限元法和有限差分法，离散元法能更好的模拟出材料裂隙产 生和发展的过程。  相似文献   

A two-stage model of fracture of rocks   总被引：7，自引：0，他引：7  

V. Kuksenko  N. Tomilin  E. Damaskinskaya  D. Lockner 《Pure and Applied Geophysics》1996,146(2):253-263

In this paper we propose a two-stage model of rock fracture. In the first stage, cracks or local regions of failure are uncorrelated and occur randomly throughout the rock in response to loading of pre-existing flaws. As damage accumulates in the rock, there is a gradual increase in the probability that large clusters of closely spaced cracks or local failure sites will develop. Based on statistical arguments, a critical density of damage will occur where clusters of flaws become large enough to lead to larger-scale failure of the rock (stage two). While crack interaction and cooperative failure is expected to occur within clusters of closely spaced cracks, the initial development of clusters is predicted based on the random variation in pre-existing flaw populations. Thus the onset of the unstable second stage in the model can be computed from the generation of random, uncorrelated damage. The proposed model incorporates notions of the kinetic (and therefore time-dependent) nature of the strength of solids as well as the discrete hierarchic structure of rocks and the flaw populations that lead to damage accumulation. The advantage offered by this model is that its salient features are valid for fracture processes occurring over a wide range of scales including earthquake processes. A notion of the rank of fracture (fracture size) is introduced, and criteria are presented for both fracture nucleation and the transition of the failure process from one scale to another.  相似文献   

边坡失稳系统的岩体与水固流耦合作用机理研究   总被引：4，自引：0，他引：4  

梁冰  薛强  王起新 《中国地质灾害与防治学报》2001,12(1):18-21

将边坡失稳问题作为一个系统来考虑，以岩体水力学为基础，研究了地下水对岩体物理力学性质的影响以及岩体受力后孔隙、裂隙改变而使其渗透性质发生变化即岩体与水耦合作用下边坡的失稳机理，建立了该系统的应力场和渗流场的数学模型，并对具体实际问题进行了数值分析。结果表明，研究岩体与水固流耦合作用下的边坡失稳问题克服了以往仅考虑渗流场或应力场而带来的缺陷，具有一定的理论意义和实际应用价值。  相似文献   

近水平双层岩基极限承载力的理论计算方法   总被引：1，自引：0，他引：1  

宋建波  刘汉超  于远忠 《地质灾害与环境保护》2001,12(2):66-68

针对上硬上软近水平双层岩基的破坏过程，考虑软弱下伏岩层对应力分布的扩散效应，提出双层岩基极限承载力的计算方法。最后，演算算例。  相似文献   

Automatic Dem Generation for Antarctic Terrain     

Andrian J. Fox  & Michael J. Gooch 《The Photogrammetric Record》2001,17(98):275-290

Automatic digital elevation model (DEM) generation has become an established technique within mapping agencies. This paper assesses the effectiveness of automatic DEM generation using area-based matching for glaciated terrain in Antarctica. DEM accuracy is assessed by comparison with check data acquired using analytical photogrammetry and independent field measurements.An optimum DEM collection strategy is identified. DEM success is linked to ground terrain type and it is found that areas of a DEM which can be collected successfully are relatively insensitive to changes in the collection strategy. A method of isolating unsuccessful areas of a DEM for manual editing is tested for Antarctic terrain. In this example, over 90% success is achieved in identifying erroneous DEM results measured against check data.  相似文献   

岩石破裂滑动过程及其声发射数值模拟   总被引：3，自引：0，他引：3  

芮勇勤  唐春安 《工程地质学报》2001,9(4):357-361

运用岩石破裂与失稳过程分析RFPA2D系统, 对滑动形成过程进行了数值模拟研究。滑动岩体似为非均匀弹 -脆岩石材料, 模拟结果再现了滑动形成从变形到破坏直至失稳的全过程及其声发射规律。  相似文献   

Research on seismic stress triggering   总被引：6，自引：0，他引：6  

万永革  吴忠良  周公威  黄静  秦立新 《地震学报(英文版)》2002,15(5):559-577

Introduction What is called seismic stress triggering refers to that stress change tensor produced by previous earthquake projected on the fault plane and slip direction of subsequent earthquakes, taking into account normal stress, pore pressure and friction coefficient, and Coulomb failure stress change DCFS can be obtained. If the direction of Coulomb failure stress changes are consistent with slip direction of subsequent seismic mechanism, e.g., Coulomb failure stress changes are positive…  相似文献   

最大往返剪切作用面上应变破坏标准的应力条件   总被引：3，自引：0，他引：3  

李刚  陈正汉  王权民 《岩土力学》2002,23(1):90-92

通过一系列的动三轴试验，探讨以应变为破坏标准的最大往返剪切作用面上的破坏应力条件。试验结果表明：破坏应力条件仍符合张克绪提出的公式，参数k,c是破坏振次与破坏应变标准的二元线性函数。  相似文献   

用弹性板理论分析顺层岩质边坡的失稳   总被引：10，自引：2，他引：10  

刘小丽  周德培 《岩土力学》2002,23(2):162-165

根据弹性板的稳定理论，利用能量法对缓倾角顺层岩质边坡的弯曲失稳机理进行了探讨，特别考虑了边坡长度的影响，推导了相应的计算公式，并通过计算实例，将文中的方法与用平面应变问题的弹性梁分析得出的结果做了对比，验证了文中方法的可行性。  相似文献   

建筑物震陷预测新方法研究   总被引：1，自引：0，他引：1  

刘义建  刘勇建 《地质灾害与环境保护》2002,13(3):47-50

利用人工神经网络的基本原理，本文修正了经典BP型神经网络的激励函数，并对学习率和训练样本进行了动态调整等多方面改进。根据70个多层建筑震陷的实测资料，在分析了建筑物震陷的影响因素基础上，提取了9个指标；采用改进后的BP算法，建立了多指标的建筑物震陷预测模型。研究结果表明，改进的BP网络性能良好，所建立的模型预测精度高，具有一定的工程实用价值；神经网络法是一种有效可行的预测新方法，人工神经网络技术具有广泛的应用前景。  相似文献