基于PSR-WSVM模型的边坡位移预测     

李建新  刘小生  肖钢  周文  刘仁志 《大地测量与地球动力学》2020,40(6):577-580

为建立高精度的边坡位移预测模型，采用相空间重构（PSR）将边坡位移时间序列数据转换为多维数据，同时构造小波核函数改进的支持向量机模型，建立PSR-WSVM模型并应用于边坡位移预测。将PSR-WSVM模型预测结果与传统支持向量机（SVM）模型、小波支持向量机（WSVM）模型和基于相空间重构的支持向量机（PSR-SVM）模型预测结果进行对比，通过平均绝对误差（MAE）、平均绝对误差百分比（MAPE）和均方根误差（RMSE）3个精度评价指标验证PSR-WSVM模型的可行性。工程实例结果表明，PSR-WSVM模型预测结果的3个精度评价指标都优于另外3种模型，边坡位移预测的精度明显提升。  相似文献   

Dynamic modelling of retrogressive landslides with emphasis on the role of clay sensitivity          下载免费PDF全文

Xue Zhang  Scott W. Sloan  Eugenio Oñate 《国际地质力学数值与分析法杂志》2018,42(15):1806-1822

This paper presents a detailed numerical study of the retrogressive failure of landslides in sensitive clays. The dynamic modelling of the landslides is carried out using a novel continuum approach, the particle finite element method, complemented with an elastoviscoplastic constitutive model. The multiwedge failure mode in the collapse is captured successfully, and the multiple retrogressive failures that have been widely observed in landslides in sensitive clays are reproduced with the failure mechanism, the kinematics, and the deposition being discussed in detail. Special attention has been paid to the role of the clay sensitivity on each retrogressive failure as well as on the final retrogression distance and the final run‐out distance via parametric studies. Moreover, the effects of the viscosity of sensitive clays on the failure are also investigated for different clay sensitivities.  相似文献   

A multiscale work-analysis approach for geotechnical structures     

Hao Xiong  Zhen-Yu Yin  François Nicot 《国际地质力学数值与分析法杂志》2019,43(6):1230-1250

This paper presents a second-order work analysis in application to geotechnical problems by using a novel effective multiscale approach. To abandon complicated equations involved in conventional phenomenological models, this multiscale approach employs a micromechanically-based formulation, in which only four parameters are involved. The multiscale approach makes it possible a coupling of the finite element method (FEM) and the micromechanically-based model. The FEM is used to solve the boundary value problem (BVP) while the micromechanically-based model is utilized at the Gauss point of the FEM. Then, the multiscale approach is used to simulate a three-dimensional triaxial test and a plain-strain footing. On the basis of the simulations, material instabilities are analyzed at both mesoscale and global scale. The second-order work criterion is then used to analyze the numerical results. It opens a road to interpret and understand the micromechanisms hiding behind the occurrence of failure in geotechnical issues.  相似文献   

Application of micropolar plasticity to post failure analysis in geomechanics     

Majid T. Manzari 《国际地质力学数值与分析法杂志》2004,28(10):1011-1032

A micropolar elastoplastic model for soils is formulated and a series of finite element analyses are employed to demonstrate the use of a micropolar continuum in overcoming the numerical difficulties encountered in application of finite element method in standard Cauchy–Boltzmann continuum. Three examples of failure analysis involving a deep excavation, shallow foundation, and a retaining wall are presented. In all these cases, it is observed that the length scale introduced in the polar continuum regularizes the incremental boundary value problem and allows the numerical simulation to be continued until a clear collapse mechanism is achieved. The issue of grain size effect is also discussed. Copyright © 2004 John Wiley & Sons, Ltd.  相似文献   

浅谈项目投资失败的原因及对策     

梁宗念 《南方国土资源》2002,15(2):69-72

地勘单位在向企业化经营转变的过程中 ,投资兴办了许多企业 ,但不少项目以失败告终。文章分析探讨了失败的原因 ,并提出相应的对策  相似文献   

Relict mountain slope deposits of northern Portugal: facies,sedimentogenesis and environmental implications     

Jean‐Pierre Texier  Jos Meireles 《第四纪科学杂志》2003,18(2):133-150

This paper deals with the formation processes and the palaeoenvironmental significance of relict slope deposits located on the uppermost part of the north Portugal mountains. For this purpose, seven key sites representative of the different lithofacies have been selected and analysed in detail. The data show that three main dynamic processes are responsible for the emplacement of regional fossil slope deposits: runoff, debris flows and dry grain flows. The ubiquity of these processes and the lack of frost‐related features or landforms do not support the existence of severe Pleistocene climates in this part of the lberian Peninsula as postulated by previous work. Pedological data gathered at one of the study sites show that a subalpine environment was probably present at 700–800 m altitude between 29 and 14 kyr. Using data from the Pyrenees Mountains, a 6.5 to 12°C depression in mean annual temperature has been tentatively postulated for this Pleniglacial period. Copyright © 2003 John Wiley & Sons, Ltd.  相似文献   

格网DEM中基于坡度信息的粗差检测与剔除方法试验     

韩玲 《地球科学与环境学报》2003,25(1):74-75

提出了一种基于格网DEM的粗差检测及剔除方法,其基本思想是对每个表面上的点,在坡度上,高程或突变量引起的形状不连续,可能被怀疑有误差,通过坡度上每个点,应用坡度逼近或改变量来计算,考虑坡度变化的相对值,并以这些相对值计算一个统计值为判断该点合法性的阈值,使计算结果更为可靠。  相似文献   

The influence of a non‐associated flow rule on the calculation of the factor of safety of soil slopes     

Yu‐Jie Wang  Jian‐Hua Yin  C. F. Lee 《国际地质力学数值与分析法杂志》2001,25(13):1351-1359

This paper presents a method that incorporates a non‐associated flow rule into the limit analysis to investigate the influence of the dilatancy angle on the factor of safety for the slope stability analysis. The proposed method retain's the advantage of the upper bound method, which is simple and has no stress involvement in the calculation of the energy dissipation and the factor of safety. Copyright © 2001 John Wiley & Sons, Ltd.  相似文献   

基于可靠度理论的黄土高边坡优化设计   总被引：11，自引：2，他引：9  

叶万军  折学森  陈志新  宋建华  邵铁全 《地球科学与环境学报》2005,27(2):82-85

对黄土高边坡进行可靠性分析，应用数学原理和优化原理，建立了黄土高边坡的优化模型，对铜黄一级公路黄土高边坡进行分析验证。结果表明，该方法计算的结果与实际较接近．应用中易操作。  相似文献   

黄土斜坡稳定性的模糊信息分析法     

王家鼎  冯学才  孟兴民 《山地学报》1991,(1)

本文基于黄土斜坡稳定性的实际资料,利用信息分配、模糊一二级近似推论及信息集中等原因建立了一套黄土斜坡稳定性的评价方法。用这套方法对一些黄土斜坡(非母体)稳定性进行了验证,其结果与实际情况一致。本方法已应用于兰州市滑坡防灾规划和皋兰山三台阁北侧几个滑坡及斜坡稳定性的研究中,效果良好。  相似文献