Acta Geotechnica - Slip zone soils play a crucial role in the evolution of landslides. In this paper, slip zone soils of the Huangtupo Landslide in the Three Gorges Reservoir area, which is an... 相似文献
In this study, two series of physical modeling experiments, with and without a grouting process, were conducted under different grouting pressures to study the effect of compaction grouting on the performance of compaction-grouted soil nails. In addition, a hyperbola-based model was proposed to describe the variation of the pullout forces with and without grouting. Some of the main conclusions drawn are as follows. First, the compaction effect initially influences the mobilized pullout force, but not the final stage of pullout; the large difference between the two series of tests in regard to the pullout force at the initial stage led to the first part of this conclusion. However, the final pullout force results of the tests, both those with and those without grouting, were similar. Second, once the soil condition changes, the compaction effect on the performance of a soil nail depends on the grouting pressure rather than the diameter of the grout bulb. Third, the difference in the soil response (i.e., vertical dilatancy and the vertical and horizontal squeezing effects) derived from the compaction grouting effect will result in the initial difference in the increased rate of the pullout force between the tests with a grouting process and those without. Finally, a hyperbola-based model was proposed to describe the variation of the pullout force of the model tests with and without grouting, through which the pullout force is available of prediction for the given diameter of grout bulb and pullout displacement.
The Longmenshan fault, which defines the eastern edge of the Tibetan Plateau, is one of the steepest margins of the plateau with a sharp elevation drop of about 4 km over a distance less than 100 km across the Longmenshan fault. The mechanism which is responsible for controlling and maintaining the elevation difference is highly debated. Using multiple observations including seismic velocity model, Moho depth, effective elastic thickness of the lithosphere, we conducted a quantitative study for elucidating the contributions from crust and lithospheric mantle by an integrated analysis of lithospheric isostasy and flexure. It is shown that the topography of the Longmenshan fault is supported by both lithospheric isostasy and flexure statically, and lower crustal channel flow and mantle convection dynamically. Different mechanisms have different weights for contribution to the topography of the Songpan-Ganzi block and the Sichuan Basin. The static and dynamic support contribute roughly the same to the topographic difference of ~4 km between the two sides of the Longmenshan fault. The static topographic difference of ~2 km is mainly resulted from the lithospheric isostasy, while the dynamic one of ~2 km is contributed by the uprising of the accumulated material in the lower crust beneath the Songpan-Ganzi block and the downward drag force caused by the upper mantle convection under the Sichuan Basin. It is thus suggested that the lower crustal flow and upper mantle convection are dynamic forces which should be taken into account in the studies on the dynamics in the Longmenshan and surrounding regions. 相似文献
1.Current status Three-dimensional(3D)inversion of geophysical EM data is generally underdetermined,non-linear,and of large-scale that is very difficult to solve by optimization.In the past two decades,with the advancement of computational equipment and numerical algorithms,3D geophysical EM inversion has made great progress.Numerous inversion codes and platforms based on the regularizations have been successfully developed and are being widely used in the industry and scientific research.The development of 3D EM inversions mainly involve the following aspects. 相似文献