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Reliability back analysis of shear strength parameters of landslide with three-dimensional upper bound limit analysis theory 总被引:1,自引:1,他引:0
It is essential to determine the shear strength parameters c and φ on the sliding surface for stability evaluation and engineering design of a landslide. In this study, a new parameter back analysis method is proposed by combining the 2D/3D upper bound method of limit analysis and reliability theory to accurately determine the shear strength parameters for a 3D slope with a single failure surface. The proposed reliability back analysis method overcomes the shortcomings of the traditional deterministic analysis method of slope stability that cannot take into account the randomness and uncertainty of geotechnical parameters. Based on the reliability theory, two methods were studied: first-order reliability method (implemented by spreadsheet and Matlab, called spreadsheet method and constrained optimization method, respectively, in this paper) and Monte Carlo simulation. The optimized values of c and φ were obtained by establishing only one balance equation with the consideration of the pore water pressure or other complex conditions, which can solve the problem of the back analysis of strength parameters for a single 3D sliding surface condition. The correlation research showed that the negative correlation between c and φ greatly affected the back analysis results, and the reliability index values were conservative without considering such a negative correlation. A case study for the back analysis of shear strength parameters is conducted based on a practical landslide model with a broken line slip surface slope in Zhuquedong village, Luxi town, Xiangxi County, Hunan Province, China, and a suggestion for the selection of landslide cross section is presented. The results show that the back analysis results determined by the reliability theory coincide well with the survey and experimental results. The proposed method is found to be more accurate and effective in determining the values of shear parameters than that of the traditional deterministic inversion method. 相似文献
275.
Assessing the digital filter method for base flow estimation in glacier melt dominated basins
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Base flow is an important component of streamflow. Although the simple digital filter method is widely used for base flow separation, the applicability in alpine rivers mainly dominated by glacier melt has not been described in detail. To assess and improve the performance of base flow estimates using the filter method for catchments dominated by glacier melt, the enhanced Soil Water Assessment Tool (SWAT) is used to obtain the estimates of streamflow and base flow for three catchments with different glacier melt contribution in arid and cold Northwestern China. The digital filter is then applied to the simulated streamflow to separate base flow and assess how well the base flow by the filter method matches these obtained using the SWAT model. In order to obtain the best match between the base flow by the filter method and those using the SWAT model, the linear regression model is used to estimate the relation between the filtered base flow and the glacier melt. It was found that the filtered base flow was matched well with base flow using the SWAT model during the low‐flow period. However, the base flow based on the digital filter method was overestimated during the high‐flow period, especially for the Manas River and Kumarik River. The base flow indexes by the digital filter estimates were 2.9%, 33.3% and 100% larger than those of the model method for the Gongnaisi River, Manas River and Kumarik River, respectively. The differences are larger with bigger glacier melt contribution. The performance of the digital filter is affected by the glacier melt, and it can be improved significantly by the combination of filtered base flow and the glacier melt. The base flow indexes by the improved filter are 1.5%, 4.4% and 10.7% larger than those of the model method for the Gongnaisi River, Manas River and Kumarik River, respectively. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
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一种恢复岩层初始厚度的新方法——鱼嘴构造研究 总被引:1,自引:0,他引:1
根据发育程度,将鱼嘴构造划分成A、B、C、D、E五种基本类型,研究了鱼嘴构造的形态特点以及鱼嘴的周缘长度与岩层初始厚度之间的关系,利用物理模拟的手段,模拟出B、C两种类型的鱼嘴构造,相应地得出了利用这两类鱼嘴构造恢复岩层初始厚度的系数k1、k2,并成功地运用于实际岩石能干层初始厚度恢复. 相似文献
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蒙古国煤炭资源丰富,但地质基础工作薄弱。位于蒙古国西部的胡硕图井田含煤地层为二叠系胡硕图组,为陆相三角洲体系沉积,含M1、M2巨厚煤层。根据煤质资料分析,区内煤类复杂,M1煤层以低灰、低挥发分、特低硫、高-特高热值、强黏结-特强黏结的焦煤(JM)为主;M2煤层以低灰、低挥发分、低硫、高-特高热值、中黏结-中强粘结的瘦煤(SM)为主;煤的变质作用类型以深成变质作用为主,同时存在动力变质作用。 相似文献
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郑州沿黄水源地地下水资源量评价 总被引:1,自引:0,他引:1
采用水文地质数值法和水均衡法,对郑州市九五滩和北郊水源地近年的运行状况进行模拟,对其满负荷开采的可行性进行评价.结果表明,两大水源地按设计进行开采,水资源量有保证. 相似文献