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931.
通过现场工程试验研究,进一步论证了水泥粘结基材替代化学粘结基材的岩质边坡绿化技术的可行性;同时提出了岩质边坡工程绿化应按"循序渐进"来进行植被恢复的理念. 相似文献
932.
通过对水泥厚层基材的直剪试验、无侧限抗压试验和三相分布、养分及pH值测定结果的综合分析,论证了水泥粘结基材替代化学粘结基材进行边坡绿化的技术可行性;同时通过比选优化了基材配比. 相似文献
933.
在反倾层状边坡内,开挖边坡并修筑隧道洞口后,出现岩体从隧道掌子面整体挤出和洞顶塌方现象,并导致边坡出现后缘拉裂、坡体内出现多处裂缝和岩块崩塌等坡体失稳迹象。通过对该边坡失稳和隧道塌方的勘察和机制分析,确定该坡体的变形破坏模式,提出针对性治理方案。 相似文献
934.
935.
936.
Accurate prediction of slope stability is a significant issue in geomechanics with many artificial intelligence (AI) techniques being utilised. However, the application of AI has not reached its full potential because of the lack of more robust algorithms. In this paper, we proposed a hybrid ensemble method for the improved prediction of slope stability using classifier ensembles and genetic algorithm. Gaussian process classification, quadratic discriminant analysis, support vector machine, artificial neural networks, adaptive boosted decision trees, and k‐nearest neighbours were chosen to be individual AI techniques, and the weighted majority voting was used as the combination method. Validation method was chosen to be the 10‐fold cross‐validation, and performance measures were selected to be the accuracy, the receiver operating characteristic curve, and the area under the receiver operating characteristic curve (AUC). Grid search and genetic algorithm were used for the hyperparameter tuning and weight tuning respectively. The results show that the proposed hybrid ensemble method has great potential in improving the prediction of slope stability. Compared with individual classifiers, the optimum ensemble classifier achieved the highest AUC value (0.943) and the highest accuracy (0.902) on the testing set, denoting that the predictive performance has been improved. The optimum ensemble classifier with the Youden's cut‐off was recommended for slope stability prediction with respect to the AUC value, the accuracy, the true positive rate, and the true negative rate. This research indicates that the use of the classifier ensembles, rather than the search for the ideal individual classifiers, might help for the slope stability prediction. 相似文献
937.
Most classical approaches for evaluating the stability of soil slopes with cracks are performed under two-dimensional (2D) condition. Three-dimensional (3D) effect and suction-induced effect of unsaturated soils are generally neglected in assessing the slope stability. This paper develops a 3D limit analysis method to evaluate the stability of an unsaturated soil slope with tension cracks under steady infiltrations. The boundary-value problem is formulated based on the 3D rotational failure mechanism by taking the effects of suction, effective unit weight, and tension crack into account. A simplified method is proposed to calculate the work rate of unsaturated soil weight. A layer-wise summation method is developed based on the divergence theorem to calculate the internal energy dissipation rate. Detailed discussions are conducted to investigate the effects of suction and Poisson's ratio on the stability of unsaturated soil slopes. Examples are given to illustrate the 3D effect, the suction-induced effect as well as the effects of infiltration and water in cracks on the slope stability. 相似文献
938.
In this work, a new analytical solution to describe tide-induced head fluctuations in aquifers of variable thickness is presented. The proposed model assumes a finite and confined aquifer with a thickness that increases or decreases quadratically with the distance to the coast. A closed-form analytical solution is obtained by solving a boundary-value problem with both a separation of variables method and a change of variables method. This solution is a generalization of the solution obtained by Cuello et al., Hydrogeological Journal, 2017, 25, 1509–1515. The analytical solution is expressed in terms of the wedging parameter, a parameter that depends on the length and thicknesses at the coast and at the inland edge of the aquifer. Positive values of the wedging parameter describe aquifers with increasing thickness towards land and negative values describe aquifers with a decreasing thickness in the inland direction. The comparison of the new solution and the solution for a finite aquifer with constant thickness indicates that the sign of the wedging parameter enhances or decreases the amplitude of the tide-induced signal. However, the differences in time-lag between both solutions are negligible near the coast. The slope factor, which quantifies the inconsistencies between aquifer diffusivities estimated from attenuation and time-lag data, is computed and analysed. Near the coast, slope factor values greater than one are obtained for negative wedging parameters while slope factor values less than one are obtained for positive wedging parameters. The analysis of the new solution also indicates that more reliable estimates of the hydraulic diffusivity can be obtained from time-lag data. 相似文献
939.
Infinite slope (IS) method is the simplest limit equilibrium method for slope stability analysis. It gives reliable results for slides where the longitudinal dimension prevails on the depth of the landslide. Usually results are conservative since ignoring the effects of the strength along lateral bounds. Here, starting from the assumption of considering the effects of the shear strength along lateral bounds by a rectangular cross section, a new expression of the safety factor is investigated, based first on an elliptical and then on a parabolic cross section of the landslide mass. The safety factor evaluated in this way can be quite different from those returned by the classic formula of IS model, in particular when the width of the landslide is narrow with respect to its depth and the ratio between the width and the depth of the landslide is lower than 5. An interesting implication of the proposed model is that if cohesion differs from zero, there is a ‘critical depth’, where the safety factor has a minimum value. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
940.
The propagation of long-waves, such as tidal waves from the coastal oceam into shallow estuarine waters,often produces asymmetries of veolcity and water level in time series resulting in long-wave breaking.Tian (1994) studied the mechanism of long-wave breaking in an infinite channel with constant depth,considering nth power bottom friction. This study is for the case of a half infinite channel with bottomslope, taking linear bottom friction into account. The wave breaking time and wave breaking location areestimated and the criteria for long-wave breaking in this particular case are obtained. The results obtainedcan also be e asily applied to the case considering wind stress. 相似文献