Case Study on Safety Assessment of Rockfall and Splash Stone Protective Structures for Secondary Excavation of Highway Slope

Rockfall occurs on the excavation of the slope of highway resulting from excavated rock pieces. In order to solve the problem of rockfall protection during the disturbance of high slope secondary excavation, rockfall analysis program RocFall was used to perform inverse calculation for rockfall path of excavation disturbed rock. Based on a case study of a reconstruction and expansion project, two rockfall movement models were proposed under excavation disturbance. Moreover, the safety of protective structures under five protection schemes and different initial rockfall movement points is evaluated according to the rockfall interceptions rate. The evaluation results were further verified by long-term field observation. The results show that the protective structure at the slope top has a better interception effect to rockfall. It was difficult to intercept the splash stone, which threats to the traffic safety of the existing roads. According to different construction points of mechanical excavation and the interception rate of splash stone by the protective structure, the forbidden region and safety region of mechanical excavation were proposed.

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PLANNING LENGTH OF LONG -TERM FIELD EXPERIMENTS THROUGH DECISION SUPPORT SYSTEMS – A CASE STUDY

Applied Ecology and Environmental Research ◽

10.15666/aeer/0602_6378 ◽

2008 ◽

Vol 6 (2) ◽

pp. 63-78 ◽

Cited By ~ 3

Author(s):

R Kaur

Keyword(s):

Decision Support ◽

Decision Support Systems ◽

Field Experiments ◽

Support Systems ◽

Term Field

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Safety Assessment of Long Term Serviced Pressure Vessels: A Case Study of Typical Refining and Chemical Plants in China

10.1115/pvp2021-61470 ◽

2021 ◽

Author(s):

Zhiyuan Han ◽

Guoshan Xie ◽

Haiyi Jiang ◽

Xiaowei Li

Keyword(s):

Pressure Vessel ◽

Safety Assessment ◽

Failure Modes ◽

Pressure Vessels ◽

Time Dependent ◽

Chemical Plants ◽

Safety Specification ◽

Detailed Assessment

Abstract The safety and risk of the long term serviced pressure vessels, especially which serviced more than 20 years, has become one of the most concerned issues in refining and chemical industry and government safety supervision in China. According to the Chinese pressure vessel safety specification TSG 21-2016 “Supervision Regulation on Safety Technology for Stationary Pressure Vessel”, if necessary, safety assessment should be performed for the pressure vessel which reaches the design service life or exceeds 20 years without a definite design life. However, the safety and risk conditions of most pressure vessels have little changes after long term serviced because their failure modes are time-independent. Thus the key problem is to identify the devices with the time-dependent failure modes and assess them based on the failure modes. This study provided a case study on 16 typical refining and chemical plants including 1870 pressure vessels serviced more than 20 years. The quantitative risk and damage mechanisms were calculated based on API 581, the time-dependent and time-independent failure modes were identified, and the typical pressure vessels were assessed based on API 579. Taking the high pressure hydrogenation plant as an example, this study gave the detailed assessment results and conclusions. The results and suggestions in this study are essential for the safety supervision and extending life of long term serviced pressure vessels in China.

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Urban traffic safety assessment: A case study of six Indian cities

IATSS Research ◽

10.1016/j.iatssr.2016.02.001 ◽

2016 ◽

Vol 39 (2) ◽

pp. 95-101 ◽

Cited By ~ 28

Author(s):

Dinesh Mohan ◽

Geetam Tiwari ◽

Sudipto Mukherjee

Keyword(s):

Traffic Safety ◽

Safety Assessment ◽

Urban Traffic ◽

Indian Cities

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Structural Safety Assessment of Marine Operations From a Long-Term Perspective: A Case Study of Offshore Wind Turbine Blade Installation

Volume 3: Structures, Safety, and Reliability ◽

10.1115/omae2019-96686 ◽

2019 ◽

Cited By ~ 1

Author(s):

Amrit Shankar Verma ◽

Zhen Gao ◽

Zhiyu Jiang ◽

Zhengru Ren ◽

Nils Petter Vedvik

Keyword(s):

Failure Probability ◽

Safety Assessment ◽

Routine Activity ◽

Structural Safety ◽

Offshore Wind Turbine ◽

Structural Failure ◽

Blade Root ◽

Extreme Response

Abstract A marine operation is a complex non-routine activity of limited duration carried out in offshore environment. Due to safety reasons, these operations are normally performed within specific sea state limits, which are derived from numerical modelling and analysis of hazardous events. In view of the uncertainties in the assessment of structural responses under stochastic environmental conditions, these limiting curves correspond to a target structural failure probability recommended in offshore standards (for example, 10−4 per operation as specified by DNV-GL). However, one of the main limitations is that these curves do not reflect site-specific safety assessment. The current paper presents a novel methodology for assessing the structural safety level of marine operations from a long-term perspective. The methodology includes estimation of extreme response distribution under all possible operational sea states (i.e. the operational domain under the limiting sea states) for a given offshore site and is compared to the response limit to obtain an average failure probability. A case study is also presented for a blade root mating process onto preassembled hub using a jack-up crane vessel and risk of impact between root and hub is considered critical. Global time-domain simulations are performed using multibody dynamics, and extreme value distributions for impact velocities are derived for different wind-wave conditions. The allowable impact velocity between the blade root and the hub is determined by an explicit finite element analysis of the damage at the blade root. Finally, the average failure probabilities considering the operational domain are obtained for four different European offshore sites and are compared to the target level of structural failure probability considered for the limiting sea states.

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