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Di Baofeng Katsenis Loukas Stamatopoulos Constantine A. Panoskaltsis Vassilis P. 《Landslides》2021,18(6):2297-2307
Landslides - Earthquake-induced landslides involve excessive movement of slopes, usually along slip surfaces. This seismic movement of slopes may depend crucially on (a) the soil response along the... 相似文献
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Constantine A. Stamatopoulos Eleni G. Velgaki Arezou Modaressi Fernando Lopez-Caballero 《Bulletin of Earthquake Engineering》2006,4(3):295-318
Gravity walls retaining dry soil are modeled as a system of two bodies: (a) the gravity wall that slides along the wall-foundation soil boundary and (b) the critical soil wedge in the soil behind the wall. The strength of the system is defined by both the frictional and the cohesional components of resistance. The angle of the prism of the critical soil wedge behind the wall is obtained using the limit equilibrium method. The model accounts for changes in the geometry of the backfill soil behind the wall by considering the displacements at the end of each time step under limit equilibrium. The model shows that the standard (single) block model is over-conservative for the extreme case of critical-to-applied-seismic acceleration ratios less than about 0.30, but works well for cases where this ratio ranges between 0.5 and 0.8. The model is applied to predict the seismic displacement of gravity walls (a) tested in the shaking-table and (b) studied numerically by elaborate elasto–plastic analyses. 相似文献
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Wu Shaolin Di Baofeng Ustin Susan L. Stamatopoulos Constantine A. Li Jierui Zuo Qi Wu Xiao Ai Nanshan 《地理学报(英文版)》2022,32(5):873-891
Journal of Geographical Sciences - The geospatial distribution pattern in traditional Chinese settlements (TCSs) reflects the traditional harmony between humans and nature, which has been learned... 相似文献
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An experimental study of the liquefaction strength of silty sands in terms of the state parameter 总被引：2，自引：0，他引：2
An elaborate program of monotonic and cyclic triaxial laboratory tests on mixtures of sand and silt with fines content 0%, 15% and 25% was performed to investigate the effect of density, consolidation stress and non-plastic fines on the liquefaction strength. The monotonic tests illustrated that the critical state lines of all mixtures do not cross each other, and are, approximately, parallel to each other. The results of the cyclic tests illustrated that the relationship between the cyclic strength and the state parameter does not depend on the consolidation stress, the soil density and the silt content. Analysis in terms of the state parameter showed that: (i) as the consolidation stress increases, the cyclic strength decreases and this effect is more pronounced as the specimens become denser, especially as the fines content increases and (ii) the cyclic strength decreases as the fines content increases and this effect is more pronounced as the specimens become denser. 相似文献
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Baofeng Di Constantine A. Stamatopoulos Miranda Dandoulaki Eleni Stavrogiannopoulou Meng Zhang Persefoni Bampina 《Natural Hazards》2017,85(2):903-927
The work considers critical slopes located at regions with high danger and proposes a method which approximately predicts the risk of earthquake-induced excessive movement of these slopes, in the case where relevant soil strength data along their slip surface do not exist. The method utilizes (1) simplified constitutive equations predicting soil response along slip surfaces and (2) a multi-block sliding system model, both recently proposed. It involves the following steps: (a) collect relevant topographic information and laboratory test results of past landslides at the region of interest, (b) (i) analyze the relevant laboratory tests to estimate the soil constitutive parameters and (ii) estimate the mobilized residual soil strength by back analysis of relevant past landslides, (c) select constitutive model parameters for future applications at the region based on step (b) and validate them based on analysis of the triggering of the past landslides and (d) apply the selected constitutive model parameters in critical slopes in the region under consideration to predict not only whether triggering occurs, but also the post-triggering slide deformation. The paper, after describing in detail the proposed method, applies it at the Wenchuan region, where the 12th May 2008 earthquake triggered many landslides. During the application, four ring shear test results and twelve landslides of the 12th May 2008 earthquake were considered. The application was successful and the following were observed: (i) in the back analyses, the multi-block model predicted reasonably well the final configuration of all slides, (ii) apart from two significantly larger back-estimated values of the residual soil strength, small scatter existed in the other back-estimated values and (iii) the selected model parameters were duly validated under step (c). Furthermore, as the back-estimated friction angle of most landslides was less than 18°, and the materials along the slip surface have a Liquid Limit value less than 25 %, it is inferred that some, or all of the slip surface during these slides, was sheared in an undrained manner. 相似文献
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Constantine A. Stamatopoulos 《Landslides》2009,6(3):191-207
The paper first proposes and validates a constitutive model simulating the change of resistance along a slip surface of clay
for both the undrained and drained cases. The proposed model is based on (a) the critical state theory and (b) the assumption
that the critical state changes once failure is reached, in terms of the further shear displacement. Under undrained conditions,
the proposed model simulates the excess pore pressure generation and, subsequently, the continuous change of resistance along
the slip surface from its initial value to the peak strength and then, at large displacement, the residual value. The latter
can be measured in constant-volume ring shear tests. Then, the developed constitutive model is implemented in the multi-block
sliding system model for the prediction of the triggering and deformation of slides. The improved model is applied at the
well-documented Fourth Avenue landslide of the 1964 Alaska earthquake. 相似文献
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Concentration of damage of buildings near the edge of cliff-type topographies has been observed during a number of recent
earthquakes and interpreted by numerical dynamic analyses that illustrate the amplification of the horizontal acceleration
and the generation of parasitic vertical acceleration near the tip of slopes. The paper performs a detailed parametric numerical
analysis to investigate the ability of mitigating this topographic effect using anchors and piles. A typical field case, the
Aegion slope of Greece, is considered. Different input motions are applied. The results illustrated that anchors and piles
can be effective in mitigating the topographic effect. The main issue is that if the part of the slope in which topographic
amplification occurs is connected to that at larger depths, in which the acceleration is smaller, then the accelerations at
the top of the slope have to become more uniform and smaller. For typical diameter and material properties of anchors/piles
the effectiveness of the mitigation depends on the length, inclination, location and number of anchors/piles. An optimum configuration
of anchors/piles mitigating the topographic effect is proposed. 相似文献
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C.A. Stamatopoulos M. Bassanou A.J. Brennan G. Madabhushi 《Soil Dynamics and Earthquake Engineering》2007,27(12):1082-1100
Concentration of damage of buildings near the edge of hard or dense cliff-type topographies has been observed during a number of recent earthquakes. These observations have been interpreted by numerical dynamic analyses that illustrate the amplification of accelerations near the edge of slopes. The paper studies the effect of mitigating these accelerations using anchors both experimentally and numerically. The main issue is that if the part of the slope in which topographic amplification occurs is connected to that in which the acceleration is less, then the accelerations have to become more uniform. The experimental study involves dynamic centrifuge tests at the Cambridge University facility both with and without anchors. The numerical procedure was verified by the seismic response of the centrifuge tests. It was then applied to the study of the effect of anchors of a typical field case, the Aegion slope, under two different input motions. In all cases anchors were found effective in mitigating the seismic motion near the edge. 相似文献
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