Study on Instability Mechanism of Super-Deep Anchorage Foundation Pit Slope of Tertiary Strong Weathered Basalts

2012 ◽  
Vol 594-597 ◽  
pp. 493-497
Author(s):  
Yue Ma ◽  
Jing Cao ◽  
Jun Xin Shen ◽  
Kai Yu Jiang ◽  
Bing Jun Zhang
Keyword(s):  
Engineering Geology ◽  
Structural Characteristics ◽  
Geological Structure ◽  
Highway Bridge ◽  
Geological Environment ◽  
Instability Mechanism ◽  
Foundation Pit ◽  
Geotechnical Parameters ◽  
Analysis Of Stability ◽  
The Stability

Taking the anchor foundation pit of the super-large highway bridge in Yunnan as an example, the stability is studied. Based on the stratum characteristics of the tertiary strong weathered basalts (TSWB) and analysis principle of engineering geology，many aspects including topography and geomorphology, geological structure, geotechnical interfaces, structural characteristics, geotechnical parameters are considered to analyze the engineering geological environment of the foundation pit. Then, the qualitative analysis of stability and possible instability mode are made.

The Numerical Analysis of Stability against Upheaval of Foundation Pit

2013 ◽  
Vol 353-356 ◽  
pp. 95-99
Author(s):  
Guo Feng Liu ◽  
Ren Wang Liang
Keyword(s):  
Soft Soil ◽  
Natural Soil ◽  
Calculation Methods ◽  
Foundation Pit ◽  
Safety Coefficient ◽  
Geological Conditions ◽  
Analysis Of Stability ◽  
The Stability ◽  
Great Region ◽  
Normal Formula

Great region discrepancy exists in natural soil, while analysis and calculation of stability against upheaval of foundation pit in current specifications is only to soft soil. In order to study the stability against upheaval of foundation pit bottom in different geological conditions, FLAC3D numerical analyzing software is adopted to calculate and visualize the influence that several factors cause to stability safety coefficient, and contrast and checking is also made with current analysis and calculation methods and normal formula of stability against upheaval of excavation. The study shows that : a increase in soil’s cohesion,internal frication angle and embedded depth can develop the stability against upheaval of foundation pit.

scholarly journals Deterministic and probabilistic 3D analysis of slope rupture at BR 116 PR/SP highway in unsaturated soil

2021 ◽  
Vol 337 ◽  
pp. 03014
Author(s):  
Bianca Riselo ◽  
Larissa Passini ◽  
Alessander Kormann
Keyword(s):  
Unsaturated Soil ◽  
3D Modelling ◽  
Water Levels ◽  
3D Analysis ◽  
Geotechnical Parameters ◽  
Stability Of Slope ◽  
Analysis Of Stability ◽  
The Stability ◽  
2D And 3D ◽  
Mass Volume

This research was developed with the purpose of presenting a deterministic and probabilistic assessment of the stability of slope located in state of São Paulo-Brazil, in the area denominated Serra Pelada, BR 116 PR/SP, with the incorporation of different suction scenarios in the unsaturated soil. The methodology was composed by 2D and 3D modelling of the slope, in the SoilVision’s SVSlope software, with the imposition of two water levels on the slope, one of 6.5 meters deep and another of 7.5 meters. The results demonstrate the variability of the probability of rupture, the safety factor, and the quantification of mobilized mass volume, in the six suction scenarios. As a result, it is possible to conclude with the analysis that the greater the surface suction in the unsaturated soil, the greater the safety factors of the slope and the lower the probability of rupture. It is also prudent to add that the incorporation of the variability of the geotechnical parameters in the probability analysis of stability, together with the 3D modelling of the slope, allow a more reliable analysis, presenting results of greater applicability in subsequent analyses. Finally, in conclusion, the studied slope is safe regarding its global stability for rupture.

Nondestructive Test on Typical Roadway Supports of a Mine via Drilling Core and Ground Penetrating Radar

2011 ◽  
Vol 368-373 ◽  
pp. 2411-2416
Author(s):  
Jian Ping Han ◽  
Hai Peng Liu
Keyword(s):  
Ground Penetrating Radar ◽  
Geological Structure ◽  
Surrounding Rock ◽  
Potential Threat ◽  
Real Performance ◽  
Design Requirements ◽  
And Performance ◽  
The Stability ◽  
Ground Penetrating ◽  
Drilling Core

Temporary or permanent supports are necessary in underground construction for maintaining the stability and limiting the damage of surrounding rock. Due to the uncertainty of geological structure, the specificity of the underground environment as well as other factors, the quality and performance of supporting structure are often difficult to satisfy the design requirements, which not only seriously affects the normal construction and operation of mines but also has the potential threat to the safety of underground production. In order to investigate the influence of the unfavorable geologic environment on supporting concrete and evaluate the real performance of roadway supports of a mine, 17 typical projects were chosen and the strength of supporting concrete was detected by nondestructive drilling core method. The result shows that the strength is widely less than the design value. Furthermore, 4 projects of them were investigated by the ground penetrating radar (GPR) in order to evaluate the feasibility of GPR in the performance investigation of the roadway supports of a mine. The results indicate that ground penetrating radar is capable of measuring the thickness of the support, the distribution of rebars and the defects of the surrounding rock.

scholarly journals Stability and Instability in the Lysogenic State of Phage Lambda

2010 ◽  
Vol 192 (22) ◽  
pp. 6064-6076 ◽  
Author(s):  
John W. Little ◽  
Christine B. Michalowski
Keyword(s):  
Intrinsic Rate ◽  
Growth Conditions ◽  
Emergent Properties ◽  
Regulatory Circuits ◽  
Stability And Instability ◽  
Natural Range ◽  
Analysis Of Stability ◽  
Stable Association ◽  
The Stability ◽  
Gene Regulatory Circuits

ABSTRACT Complex gene regulatory circuits exhibit emergent properties that are difficult to predict from the behavior of the components. One such property is the stability of regulatory states. Here we analyze the stability of the lysogenic state of phage λ. In this state, the virus maintains a stable association with the host, and the lytic functions of the virus are repressed by the viral CI repressor. This state readily switches to the lytic pathway when the host SOS system is induced. A low level of SOS-dependent switching occurs without an overt stimulus. We found that the intrinsic rate of switching to the lytic pathway, measured in a host lacking the SOS response, was almost undetectably low, probably less than 10−8/generation. We surmise that this low rate has not been selected directly during evolution but results from optimizing the rate of switching in a wild-type host over the natural range of SOS-inducing conditions. We also analyzed a mutant, λprm240, in which the promoter controlling CI expression was weakened, rendering lysogens unstable. Strikingly, the intrinsic stability of λprm240 lysogens depended markedly on the growth conditions; lysogens grown in minimal medium were nearly stable but switched at high rates when grown in rich medium. These effects on stability likely reflect corresponding effects on the strength of the prm240 promoter, measured in an uncoupled assay system. Several derivatives of λprm240 with altered stabilities were characterized. This mutant and its derivatives afford a model system for further analysis of stability.

scholarly journals Farms as a resilience factors to land degradation in peri-urban areas

2013 ◽  
Vol 44 (2s) ◽  
Author(s):  
Paolo Zappavigna ◽  
Andrea Brugnoli
Keyword(s):  
Urban Areas ◽  
Structural Characteristics ◽  
Labour Force ◽  
Social Characteristics ◽  
The Family ◽  
External Conditions ◽  
Resilience Factors ◽  
The Stability ◽  
Economic Size

The purpose of this study was the analysis of the effects induced by urban pressures on the socio-economic and territorial characteristics of the rural peri-urban areas in order to identify planning and intervention strategies aimed at enhancing the quality of agriculture and landscape. A survey was conducted in the surroundings of Parma on farms located in the vicinity of urban areas. The structural, productive and social characteristics of the family-farm units were analyzed. The survey updated an identical survey, carried out in 1986, in which it was examined a sample of 208 farms. The units surveyed were evaluated in two aspects: the “vitality”, which takes into account the structural characteristics (size, production, labour force, etc.), and the “stability”, in which a crucial role is played by the age of the conductor and the presence of a successor. It was found that only 28% of the original farm sample is still alive, one third has disappeared, 30% was absorbed by existing farms, 8% has been abandoned. The factors most favourable to the survival resulted those referred to the vitality, especially the physical and economic size of the farm, the presence of cattle, the percentage of land in property, the presence of young labour. Among the factors that predispose to the abandonment, the urbanization processes were found to be determinants, in terms of expansion of both the built-up area and of that planned as urbanisable. The research has highlighted the importance of the vitality of the farms together with a context that has maintained its original rural features. These combined aspects can better define what we call the resiliency of the landfarms system i.e. the capability of positively reacting to the variable modifications of the internal and external conditions.

scholarly journals Synthesis and characterization of one-dimensional titanate structure

2008 ◽  
Vol 2 (2) ◽  
pp. 109-114 ◽  
Author(s):  
Ljubica Nikolic ◽  
Marija Maletin ◽  
Paula Ferreira ◽  
Paula Vilarinho
Keyword(s):  
Heat Treatment ◽  
Structural Characteristics ◽  
Hydrothermal Process ◽  
Synthesis And Characterization ◽  
One Dimensional ◽  
Treatment Conditions ◽  
Alkaline Conditions ◽  
The Stability ◽  
Simple Hydrothermal Process

One-dimensional titania structures were synthesized trough a simple hydrothermal process in a highly alkaline conditions. The aim of this work was to elucidate the effect of time on the formation of 1D titanates as well on its structural characteristics (morphology, phase composition, surface area). Apart from that, the effect of heat treatment conditions on the stability of titanate based 1D samples has been investigated. The results have revealed that it is possible to form one-dimensional titanates already after 1 hour of hydrothermal synthesis. Although the composition of titanates is still under debate, the results probably correspond to the layered sodium titanates. The 1D prepared structures show a remarkable stability during heating, remaining the basic morphology and composition even up to 700?C.

scholarly journals Water Softening Mechanism and Strength Model for Saturated Carbonaceous Mudstone in Panzhihua Airport, China

2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Ziwen Wang ◽  
Jifang Du ◽  
Shuaifeng Wu ◽  
Yingqi Wei ◽  
Jianzhang Xiao ◽  
...  
Keyword(s):  
Shear Strength ◽  
Water Saturation ◽  
Structural Characteristics ◽  
Water Immersion ◽  
Analytical Techniques ◽  
Friction Angle ◽  
Mechanical Tests ◽  
Water Softening ◽  
Softening Mechanism ◽  
The Stability

To identify the water softening mechanisms that caused landslides in Panzhihua Airport, China, property and saturation tests of the mudstones extracted from a representative landslide were proposed. In this paper, water saturation tests were carried out on samples of carbonaceous mudstone collected from the east side of the No. 12 landslide at the airport. A number of different analytical techniques and mechanical tests were used to determine changes in chemical composition, mineral assemblages, and mudstone structural characteristics, including shear strength, after the mudstone had been softened. Three kinds of changes caused by water and three mudstone softening stages are proposed. The results show that the water has a significant influence on the properties of the mudstone, so the stability of the mudstone in the watery period is a big threat to the upper structure. A model for water immersion mudstone strength softening is developed. The model incorporates a permeability coefficient, the hydraulic gradient, and time; the model can be used to determine the mudstone’s shear strength and internal friction angle. This study provides a reference for the study of rock softened by water immersion.

Study on Stability of Highway Subgrade Slope in Desert Region

2013 ◽  
Vol 639-640 ◽  
pp. 974-977
Author(s):  
Jing Yu He ◽  
Guo Hua Liu
Keyword(s):  
Rapid Development ◽  
Construction Cost ◽  
Geological Environment ◽  
Highway Infrastructure ◽  
Desert Region ◽  
Environment Characteristic ◽  
Desert Areas ◽  
The Common ◽  
The Stability ◽  
Desert Highway

With the rapid development of economy, highway infrastructure is gradually extended to desert region. But at present, affected by the special engineering geological environment in desert areas, the work must be majorly planned and considered before the highway project is set that how to reduce the construction cost while ensuring the desert highway construction quality, and maximizing the maintainance and further improvement of desert environment. The wind and sand environment characteristic of desert areas is analyzed in this paper, then the common types of desert highway subgrade slope are investigated and the stability of wind-blown sand subgrade slope is studied, finally the theories and methods according to the characteristics of the desert subgrade are proposed.

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