scholarly journals Slope stability monitoring from microseismic field using polarization methodology

2003 ◽  
Vol 3 (6) ◽  
pp. 515-521 ◽  
Author(s):  
Yu. I. Kolesnikov ◽  
M. M. Nemirovich-Danchenko ◽  
S. V. Goldin ◽  
V. S. Seleznev
Keyword(s):  
Numerical Simulation ◽  
Shear Stress ◽  
Stress Concentration ◽  
Slope Stability ◽  
Tien Shan ◽  
Polarization Analysis ◽  
Horizontal Polarization ◽  
Stability Monitoring ◽  
Landslide Slope ◽  
Northern Tien Shan

Abstract. Numerical simulation of seismoacoustic emission (SAE) associated with fracturing in zones of shear stress concentration shows that SAE signals are polarized along the stress direction. The proposed polarization methodology for monitoring of slope stability makes use of three-component recording of the microseismic field on a slope in order to pick the signals of slope processes by filtering and polarization analysis. Slope activity is indicated by rather strong roughly horizontal polarization of the respective portion of the field in the direction of slope dip. The methodology was tested in microseismic observations on a landslide slope in the Northern Tien-Shan (Kyrgyzstan).

scholarly journals Numerical Simulation on the Effect of Rock Joint Roughness on the Stress Field

2022 ◽  
Vol 2148 (1) ◽  
pp. 012025
Author(s):  
J Wang ◽  
J Liu ◽  
Y Q Fu
Keyword(s):  
Numerical Simulation ◽  
Shear Stress ◽  
Stress Concentration ◽  
Stress Field ◽  
Compression Test ◽  
Maximum Shear Stress ◽  
Normal Pressure ◽  
Joint Roughness ◽  
Axial Shear ◽  
Joint Plane

Abstract In view of the influence of Joint Roughness Coefficient (JRC), which is for quantitative description of the joint surface roughness, on the stress field of the rock mass, compression test and shear-compression test were simulated on models with different joint roughness. The photoelasticity technique is applied to examine the feasibility of numerical simulation. The results show that numerical simulation results are in agreement with the results of photoelastic experiments. The stress concentration area is distributed near the joint plane. Thus, the joint plane controls the shear strength of the rock. In compression test, the maximum shear stress of the model is proportional to JRC and the normal pressure. In shear-compression test, when the ratio of the axial shear to the normal pressure is small, the maximum shear stress is nonlinearly positively correlated with JRC. When the ratio of the axial shear to the normal pressure is relatively large, the relationship curve between the maximum shear stress and JRC is parabolic. When the JRC is small, as the ratio of the axial shear force to the normal pressure increases, the maximum shear stress changes abruptly, and the maximum shear stress after the mutation decreases significantly. The reason is that the upper and lower parts of the model have slipped, resulting in a redistribution of stress. In addition, when the JRC is 6 to 12, it is more likely to cause stress concentration.

scholarly journals Mathematical modeling study of the landslide state of the slope of the mountain "SHYM BULAK"

2020 ◽  
Vol 77 (3) ◽  
pp. 259-264
Keyword(s):  
Arbitrary Shape ◽  
Strain State ◽  
Physical And Mechanical Properties ◽  
Element Model ◽  
Tien Shan ◽  
The Road ◽  
Soil Deposits ◽  
Landslide Slope ◽  
Lower Slope ◽  
Northern Tien Shan

The data on the main causes of the causing landslide on the mountain slopes, in particular, the pictures of the landslide-collapse that occurred along the road between the Medeu dam and the Shym Bulak ski sports complex in the gorge of the high slopes of the Trans-Ili Alatau in Northern Tien Shan, are given. It also offers some data on the physical and mechanical properties of loess and loamy soils, with which the cover soils of these slopes are mainly composed. A finite-element model for the study of the stress-strain state (VAT) of soil deposits of slopes of an obliquely layered structure is proposed with instructions on the features of using isoparametric elements of a quadrangular shape with four nodes of an arbitrary shape. The landslide slope of the mountain is modeled by finite elements together with the highway and the lower slope at the foot of which the Kishi Almaty River flows. The results of the VAT study are presented and the places of the slope that are vulnerable to a landslide are identified as dangerous.

scholarly journals High Mountain Asian glacier response to climate revealed by multi-temporal satellite observations since the 1960s

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Atanu Bhattacharya ◽  
Tobias Bolch ◽  
Kriti Mukherjee ◽  
Owen King ◽  
Brian Menounos ◽  
...  
Keyword(s):  
Mass Loss ◽  
River Flow ◽  
Tien Shan ◽  
High Mountain ◽  
Glacier Mass Balance ◽  
Temperature And Precipitation ◽  
Multi Temporal ◽  
The 1960S ◽  
Northern Tien Shan

AbstractKnowledge about the long-term response of High Mountain Asian glaciers to climatic variations is paramount because of their important role in sustaining Asian river flow. Here, a satellite-based time series of glacier mass balance for seven climatically different regions across High Mountain Asia since the 1960s shows that glacier mass loss rates have persistently increased at most sites. Regional glacier mass budgets ranged from −0.40 ± 0.07 m w.e.a−1 in Central and Northern Tien Shan to −0.06 ± 0.07 m w.e.a−1 in Eastern Pamir, with considerable temporal and spatial variability. Highest rates of mass loss occurred in Central Himalaya and Northern Tien Shan after 2015 and even in regions where glaciers were previously in balance with climate, such as Eastern Pamir, mass losses prevailed in recent years. An increase in summer temperature explains the long-term trend in mass loss and now appears to drive mass loss even in regions formerly sensitive to both temperature and precipitation.

Visualization of separation and reattachment in an incident shock-induced interaction

2021 ◽  
pp. 095441002098349
Author(s):  
Yun Jiao ◽  
Chengpeng Wang
Keyword(s):  
Numerical Simulation ◽  
Shock Wave ◽  
Shear Stress ◽  
Separation Bubble ◽  
Incident Shock ◽  
Incident Shock Wave ◽  
Bottom Wall ◽  
Surface Shear Stress ◽  
Surface Shear ◽  
Oil Flow

An experimental study is conducted on the qualitative visualization of the flow field in separation and reattachment flows induced by an incident shock interaction by several techniques including shear-sensitive liquid crystal coating (SSLCC), oil flow, schlieren, and numerical simulation. The incident shock wave is generated by a wedge in a Mach 2.7 duct flow, where the strength of the interaction is varied from weak to moderate by changing the angle of attack α of the wedge from 8° and 10° to 12°. The stagnation pressure upstream was set to approximately 607.9 kPa. The SSLCC technique was used to visualize the surface flow characteristics and analyze the surface shear stress fields induced by the initial incident shock wave over the bottom wall and sidewall experimentally which resolution is 3500 × 200 pixels, and the numerical simulation was also performed as the supplement for a clearer understanding to the flow field. As a result, surface shear stress over the bottom wall was visualized qualitatively by SSLCC images, and flow features such as separation/reattachment and the variations of position/size of separation bubble with wedge angle were successfully distinguished. Furthermore, analysis of shear stress trend over the bottom wall by a hue value curve indicated that the relative magnitude of shear stress increased significantly downstream of the separation bubble compared with that upstream. The variation trend of shear stress was consistent with the numerical simulation results, and the error of separation position was less than 2 mm. Finally, the three-dimensional schematic of incident shock-induced interaction has been achieved by qualitative summary by multiple techniques, including SSLCC, oil flow, schlieren, and numerical simulation.

Titanomagnetites and ilmenites from the Early Cenozoic basalts and limburgites of the Northern Tien Shan

2011 ◽  
Vol 47 (6) ◽  
pp. 475-487 ◽  
Author(s):  
A. F. Grachev ◽  
D. M. Pechersky ◽  
V. A. Tsel’movich
Keyword(s):  
Tien Shan ◽  
Early Cenozoic ◽  
Northern Tien Shan

Structure, age substantiation and tectonic setting of the Lower-Middle Ordovician volcanic-sedimentary and plutonic complexes of the western part of the Kyrgyz Range (Northern Tien Shan)

2012 ◽  
Vol 20 (4) ◽  
pp. 317-345 ◽  
Author(s):  
K. E. Degtyarev ◽  
T. Yu. Tolmacheva ◽  
A. V. Ryazantsev ◽  
A. A. Tret’yakov ◽  
A. S. Yakubchuk ◽  
...  
Keyword(s):  
Tectonic Setting ◽  
Tien Shan ◽  
Middle Ordovician ◽  
Northern Tien Shan

Influence of Slope Gradient on Distribution Rule of Geostress Field in River Valleys

2013 ◽  
Vol 404 ◽  
pp. 365-370 ◽  
Author(s):  
Qi Tao Pei ◽  
Hai Bo Li ◽  
Ya Qun Liu ◽  
Jun Gang Jiang
Keyword(s):  
Numerical Simulation ◽  
Stress Concentration ◽  
Principal Stress ◽  
Three Dimensional ◽  
Maximum Principal Stress ◽  
Slope Gradient ◽  
Bank Slope ◽  
Distribution Rule ◽  
River Valleys ◽  
Gradient Change

During the construction of hydropower station, the change of slope gradient in river valleys often takes place. In order to study influence of slope gradient change on distribution rule of geostress field, the three dimensional unloading models under different slope gradients were established by finite difference software (FLAC3D). After numerical simulation, the results were as follows: (1) The phenomenon of stress concentration at the bottom of river valleys was obvious, which appeared the typical stress fold. Both the depth of stress concentration zone and the principal stress values significantly increased with the increment of slope gradient. (2) Maximum principal stress values increased less in shallow part of upper bank slope (low stress zone) but increased more in the nearby slope foot with the increment of slope gradient, causing great difference in geostress field of bank slope. (3) There was some difference in released energy of bank slope due to slope gradient change in river valleys. In order to distinguish the difference, stress relief zone was further divided into stress stably released zone and stress instability released zone. Finally, take Ada dam area of the western route project of South-to-North Water Transfer as an example, the results by numerical simulation were reliable through comparing the distribution rule of geostress field for the dam, which could provide important reference for stability of the design and construction of steep and narrow river valleys.

scholarly journals NUMERICAL SIMULATION OF AN AGRICULTURAL SOIL SHEAR STRESS TEST

2012 ◽  
Vol 38 (1) ◽  
Author(s):  
Andrea Formato ◽  
Salvatore Faugno
Keyword(s):  
Numerical Simulation ◽  
Shear Stress ◽  
Agricultural Soil ◽  
Stress Test
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