scholarly journals Deformation Characteristics of Tianjiaba Landslide Induced by Surcharge

2021 ◽  
Vol 10 (4) ◽  
pp. 221
Author(s):  
Longju Zhang ◽  
Xingang Wang ◽  
Tangdai Xia ◽  
Baocun Yang ◽  
Bingqi Yu
Keyword(s):  
Surface Displacement ◽  
Guizhou Province ◽  
Deformation Characteristics ◽  
Surface Cracks ◽  
Sliding Surface ◽  
Maximum Displacement ◽  
Fracture Group ◽  
The North ◽  
Surface Slopes ◽  
Management Area

The Tianjiaba landslide on the Hang Rui expressway was located in the south of Sinan County, Tongren City, Guizhou Province. From the night of 2 July to the morning of 3 July 2011, numerous house cracks, foundation subsidence, and surface cracks suddenly occurred in the Tudiwan and Tianjiaba villages on the north and south sides of the management area. Based on the field geological survey, drilling, pit exploration, surface displacement, fracture observation, and deep displacement monitoring data analysis the deformation characteristics and causes of the Tianjiaba landslide were comprehensively analyzed. In this study, the landslide was divided into three areas, in which fracture group 3 was the most severe. Among the ten inclinometer holes, the sliding surface displacement of No.8 inclinometer hole was the largest, i.e., 25 mm. The sliding surface slopes of fracture groups 1, 2, and 3 were small, i.e., 12.25°, 4.97° and 6.62° to 4.64°, respectively. The results showed that the displacement values of different positions of the landslide were different, and the ground displacement value was larger than the sliding surface displacement value. The maximum displacement of the ground was 242.68 mm, which is larger than the maximum displacement of the inclinometer hole. Because the displacement of the upper part was greater than that of the lower part, bulging cracks formed in the lower part of the landslide. When the displacement of the upper part was less than that of the lower part, tension cracks formed in the lower part of the landslide. According to the surface cracks and displacement values of inclinometer holes on the sliding surface, the landslide was in the initial sliding stage and filling the platform of the management area on the hillside was the main cause of the landslide.

scholarly journals Optimization of Rocky Desertification Classification Model Based on Vegetation Type and Seasonal Characteristic

2021 ◽  
Vol 13 (15) ◽  
pp. 2935
Author(s):  
Chunhua Qian ◽  
Hequn Qiang ◽  
Feng Wang ◽  
Mingyang Li
Keyword(s):  
Learning Algorithm ◽  
Vegetation Type ◽  
Research Area ◽  
Classification Model ◽  
Guizhou Province ◽  
Model Accuracy ◽  
Spatiotemporal Evolution ◽  
Rocky Desertification ◽  
The North ◽  
Svm Model

Building a high-precision, stable, and universal automatic extraction model of the rocky desertification information is the premise for exploring the spatiotemporal evolution of rocky desertification. Taking Guizhou province as the research area and based on MODIS and continuous forest inventory data in China, we used a machine learning algorithm to build a rocky desertification model with bedrock exposure rate, temperature difference, humidity, and other characteristic factors and considered improving the model accuracy from the spatial and temporal dimensions. The results showed the following: (1) The supervised classification method was used to build a rocky desertification model, and the logical model, RF model, and SVM model were constructed separately. The accuracies of the models were 73.8%, 78.2%, and 80.6%, respectively, and the kappa coefficients were 0.61, 0.672, and 0.707, respectively. SVM performed the best. (2) Vegetation types and vegetation seasonal phases are closely related to rocky desertification. After combining them, the model accuracy and kappa coefficient improved to 91.1% and 0.861. (3) The spatial distribution characteristics of rocky desertification in Guizhou are obvious, showing a pattern of being heavy in the west, light in the east, heavy in the south, and light in the north. Rocky desertification has continuously increased from 2001 to 2019. In conclusion, combining the vertical spatial structure of vegetation and the differences in seasonal phase is an effective method to improve the modeling accuracy of rocky desertification, and the SVM model has the highest rocky desertification classification accuracy. The research results provide data support for exploring the spatiotemporal evolution pattern of rocky desertification in Guizhou.

scholarly journals The 31 March 2020 Mw 6.5 Stanley, Idaho, Earthquake: Seismotectonics and Preliminary Aftershock Analysis

2020 ◽  
Author(s):  
Lee M. Liberty ◽  
Zachery M. Lifton ◽  
T. Dylan Mikesell
Keyword(s):  
Surface Displacement ◽  
Volcanic Belt ◽  
Normal Fault ◽  
Fault System ◽  
Basin And Range Province ◽  
Ground Shaking ◽  
The North ◽  
Show Evidence ◽  
Tectonic Framework ◽  
Tectonic Belt

Abstract We report on the tectonic framework, seismicity, and aftershock monitoring efforts related to the 31 March 2020 Mw 6.5 Stanley, Idaho, earthquake. The earthquake sequence has produced both strike-slip and dip-slip motion, with minimal surface displacement or damage. The earthquake occurred at the northern limits of the Sawtooth normal fault. This fault separates the Centennial tectonic belt, a zone of active seismicity within the Basin and Range Province, from the Idaho batholith to the west and Challis volcanic belt to the north and east. We show evidence for a potential kinematic link between the northeast-dipping Sawtooth fault and the southwest-dipping Lost River fault. These opposing faults have recorded four of the five M≥6 Idaho earthquakes from the past 76 yr, including 1983 Mw 6.9 Borah Peak and the 1944 M 6.1 and 1945 M 6.0 Seafoam earthquakes. Geological and geophysical data point to possible fault boundary segments driven by pre-existing geologic structures. We suggest that the limits of both the Sawtooth and Lost River faults extend north beyond their mapped extent, are influenced by the relic trans-Challis fault system, and that seismicity within this region will likely continue for the coming years. Ongoing seismic monitoring efforts will lead to an improved understanding of ground shaking potential and active fault characteristics.

scholarly journals Deformation Characteristics of the Surrounding Rock of a Six-Lane Multiarch Tunnel under Different Excavation Conditions

2021 ◽  
Vol 2021 ◽  
pp. 1-16
Author(s):  
Lina Luo ◽  
Gang Lei ◽  
Haibo Hu
Keyword(s):  
Three Dimensional ◽  
Class Ii ◽  
Surrounding Rock ◽  
Displacement Rate ◽  
Construction Technology ◽  
Deformation Characteristics ◽  
Highway Traffic ◽  
Maximum Displacement ◽  
Element Analysis ◽  
Secondary Lining

Highway tunnel plays an increasingly prominent role in the development of high-grade highway traffic in mountainous countries or regions. Therefore, it is necessary to explore the deformation characteristics of the surrounding rock of a six-lane multiarch tunnel under different excavation conditions. Using the three-dimensional indoor model test and finite element analysis, this paper studies the dynamic mechanical behavior of a six-lane construction, reveals the whole process of the surrounding rock deformation process of class II surrounding rock under different excavation conditions, and puts forward the best construction and excavation method. The results show that the maximum displacement rate of excavation scheme III is the largest, and the maximum displacement rate of excavation scheme I is basically the same as that of excavation scheme II. Therefore, in terms of controlling the displacement rate of the surrounding rock, the effect of excavation scheme I is basically the same as that of excavation scheme II, while that of excavation scheme III is poor. In terms of construction technology, scheme II is simpler than scheme I and can ensure the integrity of the secondary lining. Therefore, in class II surrounding rock of the supporting project, it is recommended to adopt scheme II for construction.

scholarly journals Research on the Deformation Characteristics and Support Technology of a Bottom Gas Extraction Roadway under Repeated Interference

2019 ◽  
Vol 2019 ◽  
pp. 1-14
Author(s):  
Rongkun Pan ◽  
Zhihui Ma ◽  
Minggao Yu ◽  
Shuaidong Wu
Keyword(s):  
Coal Mine ◽  
Maximum Shear Stress ◽  
Mechanical Analysis ◽  
Gas Extraction ◽  
Deformation Characteristics ◽  
Maximum Displacement ◽  
Multiple Disturbances ◽  
Mining Disturbance ◽  
Mining Face

Taking Pingbao Coal Mine as the engineering background, the stress distribution, surrounding rock displacement, and plastic zone distribution characteristics of a bottom gas extraction roadway are simulated by FLAC3D under multiple disturbances. The mining disturbance due to the overlying coal seam is obtained: the deformation of the roof subsidence and lower rib closure of the bottom gas extraction roadway are larger than the floor heave and upper rib closure, respectively. According to the mechanical analysis of the bottom gas extraction roadway, the equations for calculating the displacement at each point on the surface of the bottom gas extraction roadway and the methods for calculating the maximum displacement, the maximum normal stress, and the maximum shear stress are obtained to reasonably explain the deformation of the bottom gas extraction roadway under multiple disturbances. Then, the bolt-mesh-anchor and ladder beam support mode are designed. After onsite observation of the bottom gas extraction roadway of the 12030 coal mining face of the Pingbao Coal Mine, it is concluded that the deformation characteristics of the bottom gas extraction roadway basically conform to the abovementioned equations and that the support is effective. This paper can provide a reference for the optimization of bottom gas extraction roadway positioning, the determination of support parameters, and the deformation prediction around a bottom gas extraction roadway under similar conditions.

scholarly journals On the Segmentation of the Cephalonia–Lefkada Transform Fault Zone (Greece) from an InSAR Multi-Mode Dataset of the Lefkada 2015 Sequence

2019 ◽  
Vol 11 (16) ◽  
pp. 1848
Author(s):  
Nikos Svigkas ◽  
Simone Atzori ◽  
Anastasia Kiratzi ◽  
Cristiano Tolomei ◽  
Andrea Antonioli ◽  
...  
Keyword(s):  
Fault Zone ◽  
Surface Displacement ◽  
Interferometric Synthetic Aperture Radar ◽  
Transform Fault ◽  
Earthquake Relocation ◽  
The North ◽  
Available Information ◽  
Multi Mode ◽  
Additional Constraints ◽  
Transform Fault Zone

We use Interferometric Synthetic Aperture Radar (InSAR) to study the Cephalonia–Lefkada Transform Fault Zone (CTF) in the Ionian Sea. The CTF separates continental subduction to the north from oceanic subduction to the south, along the Hellenic Subduction Zone. We exploit a rich multi-modal radar dataset of the most recent major earthquake in the region, the 17 November 2015 Mw 6.4 event, and present new surface displacement results that offer additional constraints on the fault segmentation of the area. Based on this dataset, and by exploiting available information of earthquake relocation, we propose a new rupture process for the 2015 sequence, complementary to those published already. Our modelling includes an additional southern fault segment, oblique to the segment related with the mainshock, which indicates that the CTF structure is more complex than previously believed.

scholarly journals Probabilistic Fault Displacement Hazard Analysis for North Tabriz Fault

2021 ◽  
Author(s):  
Mohamadreza Hosseyni ◽  
Habib Rahimi
Keyword(s):  
Return Period ◽  
Hazard Analysis ◽  
Probabilistic Approach ◽  
Surface Displacement ◽  
Return Periods ◽  
Surface Rupture ◽  
Slip Mechanism ◽  
The North ◽  
North Tabriz Fault ◽  
Fault Displacement

Abstract. The probabilistic fault displacement hazard analysis is one of the new methods in estimating the amount of possible displacement in the area at the hazard of causal fault rupture. In this study, using the probabilistic approach and earthquake method introduced by Youngs et al., 2003, the surface displacement of the North Tabriz fault has been investigated, and the possible displacement in different scenarios has been estimated. By considering the strike-slip mechanism of the North Tabriz fault and using the earthquake method, the probability of displacement due to surface ruptures caused by 1721 and 1780 North Tabriz fault earthquakes has been explored. These events were associated with 50 and 60 km of surface rupture, respectively. The 50–60 km long section of the North Tabriz fault was selected as the source of possible surface rupture. We considered two scenarios according to possible displacements, return periods, and magnitudes which are reported in paleoseismic studies of the North Tabriz fault. As the first scenario, possible displacement, return period, and magnitude was selected between zero to 4.5; 645 years and Mw~7.7, respectively. In the second scenario, possible displacement, return period and magnitude were selected between zero to 7.1, 300 years, and Mw~7.3, respectively. For both mentioned scenarios, the probabilistic displacements for the rate of exceedance 5 % in 50, 475, and 2475 years for the principle possible displacements (on fault) of the North Tabriz fault have been estimated. For the first and second scenarios, the maximum probabilistic displacement of the North Tabriz fault at a rate of 5 % in 50 years is estimated to be 186 and 230 cm. Also, mentioned displacements for 5 % exceedance in 475 years and 2475 years in both return periods of 645 and 300 years, are estimated at 469 and 655 cm.

Contact Analysis of Multilayered Elastic/Plastic Solids With Rough Surfaces for Decreasing Friction and Wear

2005 ◽  
Author(s):  
Shaobiao Cai ◽  
Bharat Bhushan
Keyword(s):  
Surface Roughness ◽  
Contact Area ◽  
Yield Criterion ◽  
Rough Surfaces ◽  
Three Dimensional ◽  
Surface Displacement ◽  
Maximum Displacement ◽  
Elastic Plastic ◽  
Perfectly Plastic ◽  
Von Mises

A numerical three-dimensional contact model is presented to investigate the contact behavior of multilayered elastic-perfectly plastic solids with rough surfaces. The surface displacement and contact pressure distributions are obtained based on the variational principle with fast Fourier transform (FFT)-based scheme. Von Mises yield criterion is used to determine the onset of yield. The effective hardness is modeled and plays role when the local displacement meet the maximum displacement criterion. Simulations are performed to obtain the contact pressures, fractional total contact area, fractional plastic contact area, and surface/subsurface stresses. These contact statistics are analyzed to study the effects of the layer-to-substrate ratios of stiffness and hardness, surface roughness, and layers thickness of rough, two-layered elastic/plastic solids. The results yield insight into the effects of stiffness and hardness of layers and substrates, surface roughness, and applied load on the contact performance. The layer parameters leading to low friction, stiction, and wear are investigated and identified.

scholarly journals Field monitoring on deformation of high rock slope during highway construction: A case study in Wenzhou, China

2019 ◽  
Vol 15 (12) ◽  
pp. 155014771989595 ◽  
Author(s):  
Ya-Qiong Wang ◽  
Shao-Bing Zhang ◽  
Long-Long Chen ◽  
Yong-Li Xie ◽  
Zhi-Feng Wang
Keyword(s):  
Rock Mass ◽  
Rock Slope ◽  
Surface Deformation ◽  
Surface Displacement ◽  
Vertical Displacement ◽  
Internal Displacement ◽  
Maximum Displacement ◽  
Slope Excavation ◽  
Surface Monitoring ◽  
Slope Rock

In order to study the deformation stability of rock slope during the excavation of cutting slope and ensure the safety of rock slope during construction and operation period, this article analyzed the deformation law of a typical slope excavation by monitoring the surface deformation and the internal displacement of the rock mass. The surface deformation of the slope is monitored by setting monitoring points, and the internal deformation of the slope is monitored by installing multipoint displacement meters and inclinometers. Therefore, the relationship between slope excavation and deformation is obtained. The analysis of monitoring results shows that the slope is stable before excavation, and the displacement of the slope is gradually increased with the slope excavation. After the excavation, the displacement of each slope tends to converge. The maximum displacement in surface monitoring points is 12.30 mm, and the displacement parallels to the direction of the expressway. The maximum vertical displacement in surface monitoring points is 10.60 mm which occurred in the third step; the maximum internal displacement is 11.02 mm which mainly occurs in the weak structural plane of the rock boundary. During the excavation of the weak rock slope, the slope rock mass is prone to large displacement deformation. After the excavation, the slope surface displacement and internal displacement tend to converge in a short time.

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