scholarly journals Identification Of Locking Segment In A High-Locality Landslide In Shidaguan, Southwest China

2021 ◽  
Author(s):  
Yuntao Zhou ◽  
Xiaoyan Zhao ◽  
Jiajia Zhang ◽  
Minghui Meng
Keyword(s):  
Surface Displacement ◽  
Field Investigation ◽  
Rock Masses ◽  
Investigation Methods ◽  
Overall Stability ◽  
Formation And Evolution ◽  
Developmental Characteristics ◽  
Identification Analysis ◽  
River Valleys ◽  
Sliding Zone

Abstract Identification of the locking segments is crucial for assessing the potential runout risk and the overall stability of the high-locality landslide. However, during the field investigation, it is difficult to identify the locking segments before landslide failure due to their concealment. Tizicao landslide, a high-locality landslide, is used as the field example for the locking segments identification analysis in this study. Based on the geomorphology and spatial-temporal deformation in the landslide, the identification characteristics of the locking segments of the landslide are analyzed macroscopically, and the location and area of the locking segments are determined based on the analysis results. The field investigation methods are used to verify the identification results, including the monitoring of surface and deep displacement, geological borehole drilling, and oblique photography using drones. The results show that the locking segment of the Tizicao landslide lies at the southern slope toe, which covers an area of about 4.69 × 104 m2, accounting for 15.2% of the total area of the landslide. The significant different developmental characteristics are observed in respect of the surface displacement, deep displacement, surface crack, and sliding zone soil between locking and non-locking segments. It is concluded that the formation and evolution of the locking rock masses in the Tizicao landslide are closely related to the development of local folds and S-shaped river valleys, differential unloading due to river cutting, and earthquake-induced damage to rock masses in the landslide area.

Liquefaction Potential of Clayey Soils from Wenchuan Earthquake-Induced Landslides

2013 ◽  
Vol 639-640 ◽  
pp. 850-853
Author(s):  
Chuan Sheng Chen ◽  
Hong Bin Xiao
Keyword(s):  
Wenchuan Earthquake ◽  
Clayey Soil ◽  
Sandy Soils ◽  
Field Investigation ◽  
Clayey Soils ◽  
Liquefaction Potential ◽  
Ring Shear ◽  
Practical Engineering ◽  
Ring Shear Tests ◽  
Sliding Zone

It is commonly considered that liquefaction of sandy soils is the important reason for earthquake-induced landslides,but it has been reported liquefaction phenomenon can also occur in clayey soils in the recent research. In order to clarify liquefaction potential in clayey soils ,a deeper study was conducted on the basis of field investigation and a series of laboratory tests including undrained cyclic ring-shear tests on the clayey soil samples collected from the sliding zone of the Wenchuan earthquake-induced landslides. Results show that the liquefaction potential of clayey soils is lower than that of sandy soils given the same void ratio; the soil resistance to liquefaction rises with an increase in plasticity for clayey soils; It is useful to estimate the liquefaction potential of soil by means of plasticity index and the liquefaction potential of soil in practical engineering applications.

scholarly journals Study on the Fracture Distribution Law and the Influence of Discrete Fractures on the Stability of Roadway Surrounding Rock in the Sanshandao Coastal Gold Mine, China

2019 ◽  
Vol 11 (10) ◽  
pp. 2758
Author(s):  
Gang Liu ◽  
Fengshan Ma ◽  
Haijun Zhao ◽  
Guang Li ◽  
Jiayuan Cao ◽  
...  
Keyword(s):  
Field Investigation ◽  
Surrounding Rock ◽  
Gold Mine ◽  
Rock Masses ◽  
Distribution Law ◽  
Deformation And Failure ◽  
Roadway Stability ◽  
The Stability ◽  
Fracture Distribution ◽  
Matlab Programming

Cracks are critical for the deformation and failure of rock masses, but the effects of real cracks are rarely considered when evaluating the stability and safety of practical engineering. This paper presents a study on the application of fractures in the Sanshandao Gold Mine. Field investigation and statistical analysis methods were adopted to obtain the distribution laws of the cracks. Laboratory tests, MATLAB programming, and simulation using the software, GDEM (Gdem Technology, Beijing, China, Co., Ltd.), were employed to study the mechanical behaviors of rock masses with real fractures after excavation. The main results are as follows: (1) Three sets of highly discrete cracks were developed in the study area. Their inclination and dip can be approximately considered to follow a Gaussian distribution or uniform distribution. They had close ties to the three faults developed in the mining area. (2) Compared with the model that did not consider cracks and the model processed by the equivalence idea, the surrounding rock deformation caused by excavation of the model that considered real cracks was larger than that of the former and smaller than that of the latter. However, its influence range was larger than that of the other two models. The results show that it is reasonable to use three sets of discrete cracks to characterize the fracture distribution of the surrounding rock. In the evaluation of roadway stability, it is not advisable to use the equivalence method to deal with all the cracks. Considering a part of the cracks that are compatible with the size of the calculation model, a relatively accurate evaluation can be obtained in terms of the deformation, failure, and permeability changes of the surrounding rock.

scholarly journals Analysis of rock mass behavior with Empirical and Numerical method for the construction of diversion tunnel, Laos

2022 ◽  
Vol 1212 (1) ◽  
pp. 012028
Author(s):  
D J W Mboussa ◽  
S Sun
Keyword(s):  
Numerical Modeling ◽  
Rock Mass ◽  
Field Investigation ◽  
Geological Strength Index ◽  
Rock Masses ◽  
Mountain Area ◽  
Diversion Tunnel ◽  
The Stability ◽  
The Cost ◽  
The Impact

Abstract Tunneling construction in the mountain area is a challenge for engineers and geotechnicians because of instability due to the presence of discontinuities. The objective of this paper is the modeling of surrounding rock masses for the stability of the diversion tunnel to predict the behavior of rock masses during the excavation process for the Nam Phoun hydropower station project in Laos. Field investigation and laboratories test was realized; Empirical methods as Rock mass designation and Geological Strength Index were performed, rock masses were classified in three categories (RM-1, RM-2, and RM-3); in situ stresses were obtained from existing equations, numerical modeling was performed by the 2D plane strain finite element code Phase2 developed by Rocscience, using Generalized Hoek-Brown criterion for each type of rock masses. The results of numerical modeling show the strength zones of stresses and deformations around the tunnel and predict the instabilities around the tunnel during excavations processes. Thus, for all rock’s masses, it will be necessary to consider an analysis for the supports design before the excavation’s process. The findings of this study allow a clearer understanding of the importance to assess a predictive analysis of slope stability during the feasibility phase of a project by engineers to have an idea of instabilities and its significant in preventing the impact on the cost of the project.

A Comparison of SASW Survey Results with In Situ Field Investigation Methods

2012 ◽  
Author(s):  
Marshall Lew ◽  
Kenneth H. Stokoe II ◽  
Craig A. Davis ◽  
Hari Ponnaboyina ◽  
Martin B. Hudson ◽  
...  
Keyword(s):  
Field Investigation ◽  
Investigation Methods ◽  
Survey Results

scholarly journals Failure and Remediation of an Embankment on Rigid Column-Improved Soft Soil: Case Study

2020 ◽  
Vol 2020 ◽  
pp. 1-15
Author(s):  
Shaofu Gu ◽  
Weizheng Liu ◽  
Mengyuan Ge
Keyword(s):  
Bearing Capacity ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Soft Soil ◽  
Bending Moment ◽  
Horizontal Displacement ◽  
Field Investigation ◽  
Design Stage ◽  
Overall Stability ◽  
Joint Quality

The south extension line was constructed as a new part of the Xintai Expressway in Guangdong Province, China. The project required the construction of an embankment over soft soil with a thickness of up to approximately 14.0 m, and prestressed pipe pile was selected for reinforcing the soft soil foundation to increase bearing capacity and reduce settlement. Embankment sliding with a length of approximately 110 m and cracking with a length that exceeded 300 m occurred before the construction of the pavement structure. Field investigation and theoretical analysis results indicate that the safety factor of the overall stability calculated by the existing code methods is overly large, thereby resulting in large design pile spacing, low design bearing capacity provided by single pile, and excessive load shared by subsoil between piles. These results all cause the flow sliding of soft soil between the piles and the bending fracture of some piles. The revised density method can be used to check the stability of flow sliding, and the bending moment of piles should also be checked during the embankment design stage. In addition, perpendicularity deviation and poor joint quality of pile construction also contributed to the reduction of the bearing capacity of the pipe piles and the overall stability of embankment. Reconstruction of additional rigid piles and add pile after drilling holes are adopted in the sliding and cracking sections to reinforce the failed embankment, respectively. The remediation effect was validated by the measured excess pore water pressure, subgrade settlement, and horizontal displacement.

scholarly journals Study on the Sustainable Development of Human Settlement Space Environment in Traditional Villages

2019 ◽  
Vol 11 (15) ◽  
pp. 4186 ◽  
Author(s):  
Hai-fan Wang ◽  
Shang-chia Chiou
Keyword(s):  
Field Investigation ◽  
Space Environment ◽  
Human Settlement ◽  
Spatial Form ◽  
Local Conditions ◽  
The Sustainable Development ◽  
Cultural Connotation ◽  
Religious Ecology ◽  
River Valleys ◽  
Human Exploration

The sustainability of the human settlement space environment is an eternal subject of human exploration. There hides the idea of human settlement space in an externally displayed material environment. This paper takes Dai villages in Xishuangbanna, Yunnan as the research object. Dai villages are the place where the ancestors of Dai people live, produce, and collectively construct human settlement, production, and spirit. Taking field investigation data and maps of Dai settlement areas as data sources, this paper explores Dai people’s view of human settlement space, analyzes the spatial cultural connotation of Dai villages, and the concept of sustainable human settlements ecology through the analysis of the factors of the villages’ spatial form. The survey results are as follows: (1) the villages are usually located at river valleys and basin areas, which are characteristic of facing the sun and near the water, embodying the persevering ecological concept of “adapting to local conditions and coexisting with nature”. (2) Dai people are one of the earliest “rice-growing nationalities”. Dai people’s settlements have formed a sustainable human settlement ecological space and the spatial pattern of “water-forest-field-village” is an organic whole. (3) The combination of Dai’s primitive religious ecology and Southern Buddhist culture has formed the characteristic of “advocating nature and Buddhism” and a unique concept of settlement space.

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