scholarly journals Evaluation of Global Safety Factor of Slopes during Rainfall

Landslides ◽  
1998 ◽  
Vol 35 (1) ◽  
pp. 19-23_1 ◽  
Author(s):  
Keizo UGAI ◽  
Fei CAI ◽  
Saiichi SAKAJO ◽  
Akihiko WAKAI
Keyword(s):  
Safety Factor ◽  
Global Safety Factor

Analysis for Drain Design of a Especial Rock Slopes under Rain Infiltration

2011 ◽  
Vol 90-93 ◽  
pp. 410-417
Author(s):  
Peng Yun Li ◽  
Li De Wei ◽  
Yu Bo Liu
Keyword(s):  
Safety Factor ◽  
Rock Slopes ◽  
Stability Of Slope ◽  
Rain Infiltration ◽  
Global Safety Factor ◽  
The Stability ◽  
Better Than

The study is still few for the slopes of rock with low permeation，which has interfaces for rain infiltration and no interface for effusion. The stability of slope with rainfall infiltrating under different drain condition is evaluated by the global safety factor, based on the limited equilibrium methods. The following conclusions are obtained: (1) the two rows of drains don’t enhance the value of safety factor very much, and the layout of only one row of drains is advocated；(2) the effect of the system in which drains beat in marlite is better than the system in which drains beat in the breccia；(3) the effect of the system in which drains are designed in the toe of the slope is best, and the spacing of the drains whose diameter is 0.11 m should be less the 8m .

scholarly journals Installation Time of an Initial Support for Tunnel Excavation upon the Safety Factors of Surrounding Rock

2020 ◽  
Vol 10 (16) ◽  
pp. 5653
Author(s):  
Yan-Jun Zhang ◽  
Kai Su ◽  
Hong-Ze Zhu ◽  
Zhong-Dong Qian ◽  
He-Gao Wu
Keyword(s):  
Safety Factor ◽  
Support System ◽  
Surrounding Rock ◽  
Engineering Practice ◽  
Tunnel Face ◽  
Tunnel Section ◽  
Initial Support ◽  
Global Safety Factor ◽  
The Stability ◽  
Installation Time

In engineering practice, the initial support system is commonly installed in the vicinity of the tunnel face after excavation, whereas the self-capacity of rock mass will fail to be utilized and the cost of the initial support system will be expensive. In this study, a methodology is proposed to determine the appropriate timing of initial support installation to find out the balance of tunnel safety and construction cost. Firstly, the global safety factor is introduced as the critical indicator to evaluate tunnel stability. Then, the comprehensive graphic relationship between the global safety factor and the distance to the tunnel face is established. Once the global safety factor decreases to an admissible value, the stability of the surrounding rock is in a critical state and the corresponding distance is the recommended location for installing the initial support. In these procedures, the installation time of the initial support at the typical tunnel section can be quickly designed and fed back by a direct indicator during construction. Meanwhile, several cases with different conditions have been carried out to discuss the regularity of the method.

Modeling drive wheels of hoisting machines with rubber cables

2020 ◽  
pp. 105-114
Author(s):  
V. E. Perekutnev ◽  
V. V. Zotov
Keyword(s):  
Stress State ◽  
Safety Factor ◽  
Numerical Models ◽  
Design Parameters ◽  
Potential Range ◽  
Capital Costs ◽  
Reducing Gear ◽  
Reduce Risk ◽  
Steel Cables ◽  
Sidewall Surface

Upgrading of hoisting machines aims to improve their performance, to reduce risk of accidents, and to cut down operational and capital costs. One of the redesign solutions is replacement of steel cables by rubber cables. This novation can extend life of pulling members, decrease diameters of drive and guide wheels and, consequently, elements of the whole hoisting machines: rotor, reducing gear, motor. This engineering novation needs re-designing of hoisting machines; thus, the new design should be validated, in particular, strength characteristics of the machine members. This article considers a drive wheel of a hoisting machine with a pulling belt. In order to justify the potential range of design parameters with regard to safety factor, the numerical models of different-design drive wheels are developed and their operation with pulling belt (rubber cable) is simulated in the SolidWorks environment. The data on the stress state of the wheel elements are analyzed, the most loaded points are identified, and the maximal stresses on the sidewall surface and in the spokes of wheels of different designs are plotted.

Integrating Safety-II into Safety Management

2021 ◽  
Author(s):  
Toni Wäfler ◽  
Rahel Gugerli ◽  
Giulio Nisoli
Keyword(s):  
Risk Factor ◽  
Safety Factor ◽  
Safety Management ◽  
Management Systems ◽  
Safety Management Systems ◽  
Safety Science ◽  
Human Failure ◽  
The Given ◽  
Freedom Of Action

We all aim for safe processes. However, providing safety is a complex endeavour. What is it that makes a process safe? And what is the contribution of humans? It is very common to consider humans a risk factor prone to errors. Therefore, we implement sophisticated safety management systems (SMS) in order to prevent potential "human failure". These SMS provide an impressive increase of safety. In safety science this approach is labelled "Safety-I", and it starts to be questioned because humans do not show failures only. On the contrary, they often actively contribute to safety, sometimes even by deviating from a procedure. This "Safety-II" perspective considers humans to be a "safety factor" as well because of their ability to adjust behaviour to the given situation. However, adaptability requires scope of action and this is where Safety-I and Safety-II contradict each other. While the former restricts freedom of action, the latter requires room for manoeuvring. Thus, the task of integrating the Safety-II perspective into SMS, which are traditionally Safety-I based, is difficult. This challenge was the main objective of our project. We discovered two methods that contribute to the quality of SMS by integrating Safety-II into SMS without jeopardizing the Safety-I approach.

Evaluation of Hydraulic Fracturing Models and Their Limitations to Predict No-Drill Zones for Horizontal Directional Drilling

2018 ◽  
Author(s):  
Saeed Delara ◽  
Kendra MacKay
Keyword(s):  
Hydraulic Fracturing ◽  
Safety Factor ◽  
Standard Procedure ◽  
Accurate Determination ◽  
Strength Properties ◽  
Analytical Models ◽  
Alternative Methods ◽  
Directional Drilling ◽  
Horizontal Directional Drilling ◽  
The Impact

Horizontal directional drilling (HDD) has become the preferred method for trenchless pipeline installations. Drilling pressures must be limited and a “no-drill zone” determined to avoid exceeding the strength of surrounding soil and rock. The currently accepted industry method of calculating hydraulic fracturing limiting pressure with application of an arbitrary safety factor contains several assumptions that are often not applicable to specific ground conditions. There is also no standard procedure for safety factor determination, resulting in detrimental impacts on drilling operations. This paper provides an analysis of the standard methods and proposes two alternative analytical models to more accurately determine the hydraulic fracture point and acceptable drilling pressure. These alternative methods provide greater understanding of the interaction between the drilling pressures and the surrounding ground strength properties. This allows for more accurate determination of horizontal directional drilling limitations. A comparison is presented to determine the differences in characteristics and assumptions for each model. The impact of specific soil properties and factors is investigated by means of a sensitivity analysis to determine the most critical soil information for each model.

scholarly journals Analysis of the influence of asymmetric geological conditions on stability of high arch dam

2021 ◽  
Vol 28 (1) ◽  
pp. 426-436
Author(s):  
Zelin Ding ◽  
Xuanyi Zhu ◽  
Hongyang Zhang ◽  
Hanlin Ban ◽  
Yuan Chen
Keyword(s):  
Safety Factor ◽  
Negative Impact ◽  
Decisive Role ◽  
Arch Dam ◽  
Test Method ◽  
Stable Operation ◽  
High Arch Dam ◽  
Reinforcement Scheme ◽  
Structural Plane ◽  
Geological Conditions

Abstract Geological conditions play a decisive role in the stability of arch dam engineering, and the asymmetric geological conditions of the abutment have a very negative impact on the safety of the arch dam. This article takes Lizhou arch dam as the research object, and determines that the arch dam is preliminarily affected by the geological asymmetric characteristics. Through the geomechanical model test method, the overload failure test of the Lizhou arch dam was carried out, and the resistance body, the instability deformation of the structural plane of the two dam abutments, and the influence of each structural plane on the dam body are obtained, and the safety factor is determined. According to the test results under the condition of asymmetric foundation of arch dam, for the structural plane which affects the geological asymmetry of the arch dam, the corresponding reinforcement measures are carried out. The feasibility of the reinforcement scheme is verified by the finite element method, and the safety factor after reinforcement is obtained. According to the results, it is suggested that some engineering measures can be taken to reduce the geological asymmetry between the two banks and ensure the safe and stable operation of the arch dam in the future.

scholarly journals The effect of fillet radius and length of the thick-walled cylinder on Von Mises stress and safety factor for rocket motor case

2020 ◽  
Author(s):  
Lasinta Ari Nendra Wibawa ◽  
Kuncoro Diharjo ◽  
Wijang Wisnu Raharjo ◽  
Bagus Hayatul Jihad
Keyword(s):  
Safety Factor ◽  
Rocket Motor ◽  
Von Mises Stress ◽  
Fillet Radius ◽  
Von Mises ◽  
Walled Cylinder
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